// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
// SPDX-License-Identifier: MIT

//go:build linux || freebsd

package handler

import (
	"bytes"
	"encoding/json"
	"errors"
	"fmt"
	"mime/multipart"
	"net/http"
	"net/http/httptest"
	"net/url"
	"path/filepath"
	"strings"
	"sync"
	"testing"
	"time"

	"sourcedock.dev/petrbalvin/nuntius/internal/config"
	"sourcedock.dev/petrbalvin/nuntius/internal/contactform"
	"sourcedock.dev/petrbalvin/nuntius/internal/storage"
)

// ---------------------------------------------------------------------------
// mocks
// ---------------------------------------------------------------------------

type mockSender struct {
	mu      sync.Mutex
	sent    []contactform.Request
	sendErr error
	acks    []string
	ackErr  error
}

func (m *mockSender) Send(req contactform.Request) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	m.sent = append(m.sent, req)
	return m.sendErr
}

func (m *mockSender) SendAcknowledgement(to string) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	m.acks = append(m.acks, to)
	return m.ackErr
}

func (m *mockSender) sentCount() int {
	m.mu.Lock()
	defer m.mu.Unlock()
	return len(m.sent)
}

func (m *mockSender) ackCount() int {
	m.mu.Lock()
	defer m.mu.Unlock()
	return len(m.acks)
}

type mockStore struct {
	mu        sync.Mutex
	appended  []storage.Subscriber
	appendErr error
}

func (m *mockStore) Append(sub storage.Subscriber) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	m.appended = append(m.appended, sub)
	return m.appendErr
}

type mockArchive struct {
	mu        sync.Mutex
	appended  []storage.Submission
	appendErr error
}

func (m *mockArchive) Append(sub storage.Submission) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	m.appended = append(m.appended, sub)
	return m.appendErr
}

type mockTelegram struct {
	mu        sync.Mutex
	notes     []string
	notifyErr error
}

func (m *mockTelegram) Notify(formName string, req contactform.Request) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	m.notes = append(m.notes, formName)
	return m.notifyErr
}

// ---------------------------------------------------------------------------
// helper functions
// ---------------------------------------------------------------------------

//go:fix inline
func intPtr(i int) *int { return new(i) }

//go:fix inline
func strPtr(s string) *string { return new(s) }

func testForm() *config.Form {
	return &config.Form{
		Name:             "test",
		Path:             "/test",
		Type:             "contact",
		AllowedOrigins:   []string{"https://example.com"},
		RateLimitPerHour: new(100),
		HoneypotField:    new("website"),
		From:             "noreply@test.com",
		To:               "owner@test.com",
	}
}

func testNewsletterForm() *config.Form {
	f := testForm()
	f.Type = "newsletter"
	return f
}

// testLimiterSettings mirrors the server defaults for tests that build a
// limiter without a full config.
func testLimiterSettings(perHour int) limiterSettings {
	return limiterSettings{
		perHour:      perHour,
		maxBuckets:   32768,
		cleanupEvery: time.Hour,
		maxBucketAge: 2 * time.Hour,
	}
}

// newTestRateLimiter builds a limiter with the default mechanics and no
// running cleanup goroutine.
func newTestRateLimiter(perHour int) *rateLimiter {
	s := testLimiterSettings(perHour)
	return &rateLimiter{
		perHour:      s.perHour,
		maxBuckets:   s.maxBuckets,
		cleanupEvery: s.cleanupEvery,
		maxBucketAge: s.maxBucketAge,
		buckets:      make(map[string]*bucket),
		stopCh:       make(chan struct{}),
	}
}

func newTestHandler(form *config.Form, sender formSender, store subscriberStorer) *ContactHandler {
	h := &ContactHandler{
		maxBodyBytes: 1 << 20,
		forms:        map[string]*config.Form{form.Path: form},
		senders:      map[string]formSender{form.Path: sender},
		rateLimits:   map[string]*rateLimiter{form.Path: newTestRateLimiter(form.RateLimit())},
		stores:       map[string]subscriberStorer{},
		archives:     map[string]archiveStorer{},
		notifiers:    map[string]telegramNotifier{},
	}
	h.stats = newFormStatsRegistry(h.forms)
	if store != nil {
		h.stores[form.Path] = store
	}
	return h
}

func newTestHandlerMux(t *testing.T, form *config.Form, sender formSender, store subscriberStorer) http.Handler {
	t.Helper()
	h := newTestHandler(form, sender, store)
	mux := http.NewServeMux()
	h.Register(mux)
	return mux
}

func postJSON(t *testing.T, handler http.Handler, path string, body string) *httptest.ResponseRecorder {
	t.Helper()
	req := httptest.NewRequest(http.MethodPost, path, strings.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	rec := httptest.NewRecorder()
	handler.ServeHTTP(rec, req)
	return rec
}

func postJSONWithOrigin(t *testing.T, handler http.Handler, path string, body string, origin string) *httptest.ResponseRecorder {
	t.Helper()
	req := httptest.NewRequest(http.MethodPost, path, strings.NewReader(body))
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Origin", origin)
	rec := httptest.NewRecorder()
	handler.ServeHTTP(rec, req)
	return rec
}

func decodeBody(t *testing.T, rec *httptest.ResponseRecorder, v any) {
	t.Helper()
	if err := json.NewDecoder(rec.Body).Decode(v); err != nil {
		t.Fatalf("failed to decode body: %v", err)
	}
}

// ---------------------------------------------------------------------------
// TestFormAllowed
// ---------------------------------------------------------------------------

func TestFormAllowed(t *testing.T) {
	form := &config.Form{
		AllowedOrigins: []string{"https://a.com", "https://b.com"},
	}
	tests := []struct {
		name   string
		origin string
		want   bool
	}{
		{"empty origin allowed", "", true},
		{"exact match allowed", "https://a.com", true},
		{"second match allowed", "https://b.com", true},
		{"no match disallowed", "https://evil.com", false},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			got := formAllowed(form, tt.origin)
			if got != tt.want {
				t.Errorf("formAllowed(%q) = %v, want %v", tt.origin, got, tt.want)
			}
		})
	}
}

// ---------------------------------------------------------------------------
// TestWriteCORS
// ---------------------------------------------------------------------------

func TestWriteCORS(t *testing.T) {
	allowed := []string{"https://a.com"}

	t.Run("allowed origin sets headers", func(t *testing.T) {
		w := httptest.NewRecorder()
		writeCORS(w, "https://a.com", allowed)

		if got := w.Header().Get("Access-Control-Allow-Origin"); got != "https://a.com" {
			t.Errorf("ACAO = %q, want %q", got, "https://a.com")
		}
		if got := w.Header().Get("Vary"); got != "Origin" {
			t.Errorf("Vary = %q, want %q", got, "Origin")
		}
		if got := w.Header().Get("Access-Control-Allow-Methods"); got != "POST, OPTIONS" {
			t.Errorf("ACAM = %q, want POST, OPTIONS", got)
		}
	})

	t.Run("disallowed origin sets nothing", func(t *testing.T) {
		w := httptest.NewRecorder()
		writeCORS(w, "https://evil.com", allowed)

		if got := w.Header().Get("Access-Control-Allow-Origin"); got != "" {
			t.Errorf("ACAO = %q, want empty", got)
		}
		if got := w.Header().Get("Access-Control-Allow-Methods"); got != "" {
			t.Errorf("ACAM = %q, want empty", got)
		}
	})
}

// ---------------------------------------------------------------------------
// TestClientIP
// ---------------------------------------------------------------------------

func TestClientIP(t *testing.T) {
	tests := []struct {
		name       string
		trustProxy bool
		xff        string
		xri        string
		remoteAddr string
		want       string
	}{
		{
			name:       "peer address is used when proxy headers are not trusted",
			trustProxy: false,
			xff:        "1.2.3.4",
			xri:        "",
			remoteAddr: "10.0.0.1:1234",
			want:       "10.0.0.1",
		},
		{
			name:       "spoofed forwarded headers ignored without proxy trust",
			trustProxy: false,
			xff:        "203.0.113.9",
			xri:        "198.51.100.9",
			remoteAddr: "10.0.0.1:1234",
			want:       "10.0.0.1",
		},
		{
			name:       "X-Forwarded-For single IP with proxy trust",
			trustProxy: true,
			xff:        "1.2.3.4",
			xri:        "",
			remoteAddr: "10.0.0.1:1234",
			want:       "1.2.3.4",
		},
		{
			name:       "X-Forwarded-For multiple IPs takes first hop",
			trustProxy: true,
			xff:        "1.2.3.4, 2.3.4.5, 3.4.5.6",
			xri:        "",
			remoteAddr: "10.0.0.1:1234",
			want:       "1.2.3.4",
		},
		{
			name:       "X-Real-IP takes priority over RemoteAddr with proxy trust",
			trustProxy: true,
			xff:        "",
			xri:        "5.6.7.8",
			remoteAddr: "10.0.0.1:1234",
			want:       "5.6.7.8",
		},
		{
			name:       "RemoteAddr fallback when proxy trusted but no headers set",
			trustProxy: true,
			xff:        "",
			xri:        "",
			remoteAddr: "9.10.11.12:8080",
			want:       "9.10.11.12",
		},
		{
			name:       "RemoteAddr without port",
			trustProxy: false,
			xff:        "",
			xri:        "",
			remoteAddr: "9.10.11.12",
			want:       "9.10.11.12",
		},
		{
			name:       "IPv6 RemoteAddr with port",
			trustProxy: false,
			xff:        "",
			xri:        "",
			remoteAddr: "[::1]:12345",
			want:       "[::1]",
		},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			req := httptest.NewRequest(http.MethodGet, "/", nil)
			if tt.xff != "" {
				req.Header.Set("X-Forwarded-For", tt.xff)
			}
			if tt.xri != "" {
				req.Header.Set("X-Real-IP", tt.xri)
			}
			req.RemoteAddr = tt.remoteAddr
			got := ClientIP(req, tt.trustProxy)
			if got != tt.want {
				t.Errorf("ClientIP() = %q, want %q", got, tt.want)
			}
		})
	}
}

// A caller that rotates a forged X-Forwarded-For value must not receive a
// fresh rate-limit bucket unless proxy headers are explicitly trusted.
func TestHandlerRateLimitIgnoresSpoofedForwardedFor(t *testing.T) {
	form := testForm()
	form.RateLimitPerHour = new(1)
	sender := &mockSender{}
	h := &ContactHandler{
		trustProxy:   false,
		maxBodyBytes: 1 << 20,
		forms:        map[string]*config.Form{form.Path: form},
		senders:      map[string]formSender{form.Path: sender},
		rateLimits:   map[string]*rateLimiter{form.Path: newTestRateLimiter(form.RateLimit())},
		stores:       map[string]subscriberStorer{},
	}
	mux := http.NewServeMux()
	h.Register(mux)

	rec1 := postJSON(t, mux, "/test",
		`{"name":"Alice","email":"a@b.com","message":"Hello there!"}`)
	req2 := httptest.NewRequest(http.MethodPost, "/test",
		strings.NewReader(`{"name":"Bob","email":"b@b.com","message":"Hello there!"}`))
	req2.Header.Set("Content-Type", "application/json")
	req2.Header.Set("X-Forwarded-For", "203.0.113.99") // forged identity rotation
	rec2 := httptest.NewRecorder()
	mux.ServeHTTP(rec2, req2)

	if rec1.Code != http.StatusOK {
		t.Fatalf("first request status = %d, want %d", rec1.Code, http.StatusOK)
	}
	if rec2.Code != http.StatusTooManyRequests {
		t.Fatalf("second request status = %d, want %d (forged header must not reset the bucket)",
			rec2.Code, http.StatusTooManyRequests)
	}
}

// With an explicitly trusted proxy in front, distinct forwarded IPs get
// distinct buckets.
func TestHandlerRateLimitHonoursTrustedForwardedFor(t *testing.T) {
	form := testForm()
	form.RateLimitPerHour = new(1)
	sender := &mockSender{}
	h := &ContactHandler{
		trustProxy:   true,
		maxBodyBytes: 1 << 20,
		forms:        map[string]*config.Form{form.Path: form},
		senders:      map[string]formSender{form.Path: sender},
		rateLimits:   map[string]*rateLimiter{form.Path: newTestRateLimiter(form.RateLimit())},
		stores:       map[string]subscriberStorer{},
	}
	mux := http.NewServeMux()
	h.Register(mux)

	post := func(xff string) *httptest.ResponseRecorder {
		req := httptest.NewRequest(http.MethodPost, "/test",
			strings.NewReader(`{"name":"Alice","email":"a@b.com","message":"Hello there!"}`))
		req.Header.Set("Content-Type", "application/json")
		req.Header.Set("X-Forwarded-For", xff)
		rec := httptest.NewRecorder()
		mux.ServeHTTP(rec, req)
		return rec
	}

	if rec := post("203.0.113.1"); rec.Code != http.StatusOK {
		t.Fatalf("first forwarded client status = %d, want %d", rec.Code, http.StatusOK)
	}
	if rec := post("203.0.113.2"); rec.Code != http.StatusOK {
		t.Fatalf("second forwarded client status = %d, want %d (separate bucket expected)",
			rec.Code, http.StatusOK)
	}
}

// ---------------------------------------------------------------------------
// TestRateLimiterAllow
// ---------------------------------------------------------------------------

func TestRateLimiterAllow(t *testing.T) {
	perHour := 3
	rl := newTestRateLimiter(perHour)

	ip := "10.0.0.1"

	// First perHour requests should be allowed.
	for i := range perHour {
		if !rl.allow(ip) {
			t.Fatalf("allow() call %d was blocked, want allowed", i+1)
		}
	}

	// Next request should be blocked.
	if rl.allow(ip) {
		t.Fatal("allow() after exhausting tokens was allowed, want blocked")
	}
}

// ---------------------------------------------------------------------------
// TestRateLimiterRefill
// ---------------------------------------------------------------------------

func TestRateLimiterRefill(t *testing.T) {
	// 3600 tokens per hour = 1 token per second.
	perHour := 3600
	rl := newTestRateLimiter(perHour)

	ip := "10.0.0.1"

	// Exhaust all tokens.
	allowed := 0
	for rl.allow(ip) {
		allowed++
	}
	if allowed != perHour {
		t.Fatalf("exhausted %d tokens, want %d", allowed, perHour)
	}

	// Immediately another request should be blocked (rate = 1 token/sec).
	if rl.allow(ip) {
		t.Fatal("allow() immediately after exhausting was allowed, want blocked")
	}

	// Wait for at least 2 tokens to refill (2 seconds + margin).
	time.Sleep(2100 * time.Millisecond)

	// Should now allow 2 requests.
	for i := range 2 {
		if !rl.allow(ip) {
			t.Fatalf("allow() after refill call %d was blocked, want allowed", i+1)
		}
	}

	// Third request after only 2 sec of refill should be blocked.
	if rl.allow(ip) {
		t.Fatal("allow() after refill of only 2 tokens was allowed, want blocked")
	}
}

// ---------------------------------------------------------------------------
// TestRateLimiterCleanup
// ---------------------------------------------------------------------------

func TestRateLimiterCleanup(t *testing.T) {
	rl := &rateLimiter{
		perHour: 10,
		buckets: make(map[string]*bucket),
	}

	// Add a very old entry (3 hours ago).
	rl.buckets["old-ip"] = &bucket{
		tokens: 0,
		last:   time.Now().Add(-3 * time.Hour),
	}

	// Add a recent entry (30 seconds ago).
	rl.buckets["recent-ip"] = &bucket{
		tokens: 5,
		last:   time.Now().Add(-30 * time.Second),
	}

	// Cleanup entries older than 2 hours.
	rl.cleanup(2 * time.Hour)

	if _, ok := rl.buckets["old-ip"]; ok {
		t.Error("old-ip was not cleaned up, want removed")
	}
	if _, ok := rl.buckets["recent-ip"]; !ok {
		t.Error("recent-ip was cleaned up, want kept")
	}
}

// ---------------------------------------------------------------------------
// TestRateLimiterZeroPerHour
// ---------------------------------------------------------------------------

func TestRateLimiterZeroPerHour(t *testing.T) {
	form := testForm()
	form.RateLimitPerHour = new(0)
	form.AllowedOrigins = nil // allow all

	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	// Send many requests rapidly: none should be rate-limited.
	const n = 50
	for i := range n {
		rec := postJSON(t, mux, "/test",
			`{"name":"Alice","email":"a@b.com","message":"Hello there!"}`)
		if rec.Code == http.StatusTooManyRequests {
			t.Fatalf("request %d rate-limited with perHour=0", i+1)
		}
	}

	if sender.sentCount() != n {
		t.Errorf("sent %d requests, want %d", sender.sentCount(), n)
	}
}

// ---------------------------------------------------------------------------
// TestRateLimiterMultipleIPs
// ---------------------------------------------------------------------------

func TestRateLimiterMultipleIPs(t *testing.T) {
	perHour := 2
	rl := newTestRateLimiter(perHour)

	ipA := "10.0.0.1"
	ipB := "10.0.0.2"

	// Exhaust ipA's tokens.
	for i := range perHour {
		if !rl.allow(ipA) {
			t.Fatalf("ipA call %d blocked, want allowed", i+1)
		}
	}
	if rl.allow(ipA) {
		t.Fatal("ipA after exhaust was allowed, want blocked")
	}

	// ipB should still have all its tokens.
	for i := range perHour {
		if !rl.allow(ipB) {
			t.Fatalf("ipB call %d blocked, want allowed", i+1)
		}
	}
	if rl.allow(ipB) {
		t.Fatal("ipB after exhaust was allowed, want blocked")
	}
}

// ---------------------------------------------------------------------------
// TestMinF
// ---------------------------------------------------------------------------

// ---------------------------------------------------------------------------
// TestRespondOK
// ---------------------------------------------------------------------------

func TestRespondOK(t *testing.T) {
	w := httptest.NewRecorder()
	respondOK(w)

	if w.Code != http.StatusOK {
		t.Errorf("status = %d, want %d", w.Code, http.StatusOK)
	}

	var resp contactform.Response
	decodeBody(t, w, &resp)
	if !resp.OK {
		t.Errorf("OK = %v, want true", resp.OK)
	}
}

// ---------------------------------------------------------------------------
// TestRespondError
// ---------------------------------------------------------------------------

func TestRespondError(t *testing.T) {
	w := httptest.NewRecorder()
	respondError(w, http.StatusBadRequest, "invalid_body", "Could not parse request body.")

	if w.Code != http.StatusBadRequest {
		t.Errorf("status = %d, want %d", w.Code, http.StatusBadRequest)
	}

	var resp contactform.ErrorResponse
	decodeBody(t, w, &resp)
	if resp.Error != "invalid_body" {
		t.Errorf("error = %q, want %q", resp.Error, "invalid_body")
	}
	if resp.Message != "Could not parse request body." {
		t.Errorf("message = %q, want %q", resp.Message, "Could not parse request body.")
	}
}

// ---------------------------------------------------------------------------
// TestHealth
// ---------------------------------------------------------------------------

func TestHealth(t *testing.T) {
	form := testForm()
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	req := httptest.NewRequest(http.MethodGet, "/health", nil)
	rec := httptest.NewRecorder()
	mux.ServeHTTP(rec, req)

	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusOK)
	}

	var resp map[string]any
	decodeBody(t, rec, &resp)
	if status, ok := resp["status"]; !ok || status != "ok" {
		t.Errorf("status = %v, want ok", status)
	}
}

// ---------------------------------------------------------------------------
// TestHandlerOptions
// ---------------------------------------------------------------------------

func TestHandlerOptions(t *testing.T) {
	form := testForm()
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	req := httptest.NewRequest(http.MethodOptions, "/test", nil)
	req.Header.Set("Origin", "https://example.com")
	rec := httptest.NewRecorder()
	mux.ServeHTTP(rec, req)

	if rec.Code != http.StatusNoContent {
		t.Errorf("status = %d, want %d", rec.Code, http.StatusNoContent)
	}
	if got := rec.Header().Get("Access-Control-Allow-Origin"); got != "https://example.com" {
		t.Errorf("ACAO = %q, want %q", got, "https://example.com")
	}
}

// ---------------------------------------------------------------------------
// TestHandlerOriginNotAllowed
// ---------------------------------------------------------------------------

func TestHandlerOriginNotAllowed(t *testing.T) {
	form := testForm()
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	rec := postJSONWithOrigin(t, mux, "/test",
		`{"name":"A","email":"a@b.com","message":"Hello there!"}`,
		"https://evil.com")

	if rec.Code != http.StatusForbidden {
		t.Errorf("status = %d, want %d", rec.Code, http.StatusForbidden)
	}

	var resp contactform.ErrorResponse
	decodeBody(t, rec, &resp)
	if resp.Error != "origin_not_allowed" {
		t.Errorf("error = %q, want origin_not_allowed", resp.Error)
	}

	if sender.sentCount() != 0 {
		t.Errorf("sender called %d times, want 0", sender.sentCount())
	}
}

// ---------------------------------------------------------------------------
// TestHandlerRateLimited
// ---------------------------------------------------------------------------

func TestHandlerRateLimited(t *testing.T) {
	form := testForm()
	form.RateLimitPerHour = new(1)
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	// First request should succeed.
	rec1 := postJSON(t, mux, "/test",
		`{"name":"Alice","email":"a@b.com","message":"Hello there!"}`)
	if rec1.Code != http.StatusOK {
		t.Fatalf("first request status = %d, want %d", rec1.Code, http.StatusOK)
	}

	// Second request should be rate-limited.
	rec2 := postJSON(t, mux, "/test",
		`{"name":"Bob","email":"b@b.com","message":"Hello there!"}`)
	if rec2.Code != http.StatusTooManyRequests {
		t.Fatalf("second request status = %d, want %d", rec2.Code, http.StatusTooManyRequests)
	}

	var resp contactform.ErrorResponse
	decodeBody(t, rec2, &resp)
	if resp.Error != "rate_limited" {
		t.Errorf("error = %q, want rate_limited", resp.Error)
	}
}

// ---------------------------------------------------------------------------
// TestHandlerRateLimitDisabled
// ---------------------------------------------------------------------------

func TestHandlerRateLimitDisabled(t *testing.T) {
	form := testForm()
	form.RateLimitPerHour = new(0) // explicit zero disables the limit
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	// Far more requests than the default bucket would allow.
	for i := range 5 {
		rec := postJSON(t, mux, "/test",
			fmt.Sprintf(`{"name":"User%d","email":"u%d@b.com","message":"Hello there!"}`, i, i))
		if rec.Code != http.StatusOK {
			t.Fatalf("request %d status = %d, want %d (limit should be disabled)", i, rec.Code, http.StatusOK)
		}
	}
}

// ---------------------------------------------------------------------------
// TestHandlerInvalidBody
// ---------------------------------------------------------------------------

func TestHandlerInvalidBody(t *testing.T) {
	form := testForm()
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	rec := postJSON(t, mux, "/test", `not json`)

	if rec.Code != http.StatusBadRequest {
		t.Errorf("status = %d, want %d", rec.Code, http.StatusBadRequest)
	}

	var resp contactform.ErrorResponse
	decodeBody(t, rec, &resp)
	if resp.Error != "invalid_body" {
		t.Errorf("error = %q, want invalid_body", resp.Error)
	}
}

// ---------------------------------------------------------------------------
// TestHandlerValidationError
// ---------------------------------------------------------------------------

func TestHandlerValidationError(t *testing.T) {
	form := testForm()
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	// Empty name triggers validation error.
	rec := postJSON(t, mux, "/test",
		`{"name":"","email":"a@b.com","message":"hi"}`)

	if rec.Code != http.StatusBadRequest {
		t.Errorf("status = %d, want %d", rec.Code, http.StatusBadRequest)
	}

	var resp contactform.ErrorResponse
	decodeBody(t, rec, &resp)
	if resp.Error != "validation" {
		t.Errorf("error = %q, want validation", resp.Error)
	}
	if len(resp.Details) == 0 {
		t.Fatal("details empty, want validation field errors")
	}

	if sender.sentCount() != 0 {
		t.Errorf("sender called %d times even with validation error", sender.sentCount())
	}
}

// ---------------------------------------------------------------------------
// TestHandlerServicePolicy
// ---------------------------------------------------------------------------

// A payload without a service field is always legitimate: the field is
// optional, and petrbalvin.org posts without it.
func TestHandlerPayloadWithoutServicePasses(t *testing.T) {
	form := testForm() // contact type: the built-in default list applies
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	rec := postJSON(t, mux, "/test",
		`{"name":"Alice","email":"a@example.com","message":"Hello there!"}`)
	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusOK)
	}
	if sender.sentCount() != 1 {
		t.Errorf("sender called %d times, want 1", sender.sentCount())
	}
}

// A configured services list drives the per-form allow-list: a listed
// value passes, an unlisted one is rejected, and the empty value keeps
// passing.
func TestHandlerConfiguredServices(t *testing.T) {
	form := testForm()
	form.Services = []string{"consulting", "support"}
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	if rec := postJSON(t, mux, "/test",
		`{"name":"Alice","email":"a@example.com","service":"consulting","message":"Hello there!"}`); rec.Code != http.StatusOK {
		t.Errorf("listed service status = %d, want %d", rec.Code, http.StatusOK)
	}
	if rec := postJSON(t, mux, "/test",
		`{"name":"Alice","email":"a@example.com","service":"","message":"Hello there!"}`); rec.Code != http.StatusOK {
		t.Errorf("empty service status = %d, want %d", rec.Code, http.StatusOK)
	}

	rec := postJSON(t, mux, "/test",
		`{"name":"Alice","email":"a@example.com","service":"hairstyling","message":"Hello there!"}`)
	if rec.Code != http.StatusBadRequest {
		t.Fatalf("unlisted service status = %d, want %d", rec.Code, http.StatusBadRequest)
	}
	var resp contactform.ErrorResponse
	decodeBody(t, rec, &resp)
	if len(resp.Details) == 0 || resp.Details[0].Field != "service" {
		t.Errorf("details = %+v, want a service field error", resp.Details)
	}
	// Only the two accepted posts reached the sender.
	if sender.sentCount() != 2 {
		t.Errorf("sender called %d times, want 2", sender.sentCount())
	}
}

// A custom services list on a feedback form switches the field into that
// form's validation too.
func TestHandlerConfiguredServicesOnFeedback(t *testing.T) {
	form := testNewsletterForm()
	form.Type = "feedback"
	form.Services = []string{"bug", "idea"}
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	if rec := postJSON(t, mux, "/test",
		`{"name":"Alice","email":"a@example.com","service":"idea","message":"Hello there!"}`); rec.Code != http.StatusOK {
		t.Errorf("listed service on feedback status = %d, want %d", rec.Code, http.StatusOK)
	}
	if rec := postJSON(t, mux, "/test",
		`{"name":"Alice","email":"a@example.com","message":"Hello there!"}`); rec.Code != http.StatusOK {
		t.Errorf("no service on feedback status = %d, want %d", rec.Code, http.StatusOK)
	}
	if rec := postJSON(t, mux, "/test",
		`{"name":"Alice","email":"a@example.com","service":"hairstyling","message":"Hello there!"}`); rec.Code != http.StatusBadRequest {
		t.Errorf("unlisted service on feedback status = %d, want %d", rec.Code, http.StatusBadRequest)
	}
}

// A false require_name takes the name field out of the validation.
func TestHandlerRequireNameFromConfig(t *testing.T) {
	form := testForm()
	form.RequireName = new(false)
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	rec := postJSON(t, mux, "/test", `{"email":"a@example.com","message":"Hello there!"}`)
	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusOK)
	}
	if sender.sentCount() != 1 {
		t.Errorf("sender called %d times, want 1", sender.sentCount())
	}
}

// ---------------------------------------------------------------------------
// TestHandlerHoneypot
// ---------------------------------------------------------------------------

func TestHandlerHoneypot(t *testing.T) {
	form := testForm()
	form.HoneypotField = new("website")
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	// A non-empty honeypot field must be silently dropped: HTTP 200 but
	// no email sent.
	rec := postJSON(t, mux, "/test",
		`{"name":"Alice","email":"a@b.com","message":"Hello there!","website":"bot_value"}`)

	if rec.Code != http.StatusOK {
		t.Errorf("status = %d, want %d", rec.Code, http.StatusOK)
	}
	if n := sender.sentCount(); n != 0 {
		t.Errorf("expected honeypot to suppress send, got %d sends", n)
	}
}

func TestHandlerHoneypotEmptyPasses(t *testing.T) {
	form := testForm()
	form.HoneypotField = new("website")
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	// An empty honeypot field is legitimate human behaviour.
	rec := postJSON(t, mux, "/test",
		`{"name":"Alice","email":"a@b.com","message":"Hello there!","website":""}`)

	if rec.Code != http.StatusOK {
		t.Errorf("status = %d, want %d", rec.Code, http.StatusOK)
	}
	if n := sender.sentCount(); n != 1 {
		t.Errorf("expected exactly 1 send, got %d", n)
	}
}

func TestHandlerBodyTooLarge(t *testing.T) {
	// A handler configured with a small body limit must reject anything
	// larger with 413 before the sender is reached.
	form := testForm()
	sender := &mockSender{}
	h := newTestHandler(form, sender, nil)
	h.maxBodyBytes = 64
	mux := http.NewServeMux()
	h.Register(mux)

	body := fmt.Sprintf(`{"name":"A","email":"a@b.com","message":"%s"}`, strings.Repeat("x", 200))
	rec := postJSON(t, mux, "/test", body)

	if rec.Code != http.StatusRequestEntityTooLarge {
		t.Errorf("status = %d, want %d", rec.Code, http.StatusRequestEntityTooLarge)
	}
	if n := sender.sentCount(); n != 0 {
		t.Errorf("expected no send for oversized body, got %d", n)
	}
}

// The configured body limit must not clip legitimate payloads.
func TestHandlerBodyWithinConfiguredLimit(t *testing.T) {
	form := testForm()
	sender := &mockSender{}
	h := newTestHandler(form, sender, nil)
	h.maxBodyBytes = 64
	mux := http.NewServeMux()
	h.Register(mux)

	rec := postJSON(t, mux, "/test", `{"name":"Alice","email":"a@b.com","message":"Hello there!"}`)
	if rec.Code != http.StatusOK {
		t.Errorf("status = %d, want %d", rec.Code, http.StatusOK)
	}
}

// A configured bucket cap bounds how many distinct IPs one form serves
// between cleanup sweeps: once full, unknown IPs are denied.
func TestHandlerRateLimitBucketCapFromConfig(t *testing.T) {
	form := testForm()
	sender := &mockSender{}
	h := newTestHandler(form, sender, nil)
	h.rateLimits["/test"] = newRateLimiter(limiterSettings{
		perHour:      100,
		maxBuckets:   1,
		cleanupEvery: time.Hour,
		maxBucketAge: 2 * time.Hour,
	})
	mux := http.NewServeMux()
	h.Register(mux)

	if rec := postJSON(t, mux, "/test",
		`{"name":"Alice","email":"a@b.com","message":"Hello there!"}`); rec.Code != http.StatusOK {
		t.Fatalf("first IP status = %d, want %d", rec.Code, http.StatusOK)
	}

	// A second distinct IP finds the map full and is denied.
	req := httptest.NewRequest(http.MethodPost, "/test",
		strings.NewReader(`{"name":"Bob","email":"b@b.com","message":"Hello there!"}`))
	req.Header.Set("Content-Type", "application/json")
	req.RemoteAddr = "203.0.113.50:4321"
	rec := httptest.NewRecorder()
	mux.ServeHTTP(rec, req)
	if rec.Code != http.StatusTooManyRequests {
		t.Errorf("second IP status = %d, want %d (bucket cap exhausted)", rec.Code, http.StatusTooManyRequests)
	}
}

// New must wire the configured policies into the handler: body cap,
// limiter mechanics, pending TTL and the per-form validation policy.
func TestNewWiresConfiguredPolicies(t *testing.T) {
	dir := t.TempDir()
	cfg := &config.Config{
		DataDir: dir,
		Server: config.ServerConfig{
			MaxBodyBytes:                 new(4096),
			RateLimitMaxBuckets:          new(7),
			RateLimitCleanupSeconds:      new(60),
			RateLimitMaxBucketAgeSeconds: new(120),
		},
		Forms: []config.Form{
			{Name: "n", Path: "/n", Type: "newsletter", To: "a@b.c",
				PendingTTLSeconds: new(3600),
				SMTP:              config.SMTPConfig{Host: "h", Port: 587, User: "u"}},
		},
	}
	h := New(cfg)

	if h.maxBodyBytes != 4096 {
		t.Errorf("maxBodyBytes = %d, want 4096", h.maxBodyBytes)
	}
	lim := h.rateLimits["/n"]
	if lim.maxBuckets != 7 || lim.cleanupEvery != time.Minute || lim.maxBucketAge != 2*time.Minute {
		t.Errorf("limiter mechanics = %d/%v/%v, want 7/1m/2m",
			lim.maxBuckets, lim.cleanupEvery, lim.maxBucketAge)
	}
	if got := h.pendings["/n"].TTL(); got != time.Hour {
		t.Errorf("pending TTL = %v, want 1h", got)
	}
	h.Close()
}

// ---------------------------------------------------------------------------
// TestHandlerSendSuccess
// ---------------------------------------------------------------------------

func TestHandlerSendSuccess(t *testing.T) {
	form := testForm()
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	rec := postJSON(t, mux, "/test",
		`{"name":"Alice","email":"a@example.com","message":"Hello there!"}`)

	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusOK)
	}

	var resp contactform.Response
	decodeBody(t, rec, &resp)
	if !resp.OK {
		t.Errorf("OK = %v, want true", resp.OK)
	}

	if sender.sentCount() != 1 {
		t.Fatalf("sender called %d times, want 1", sender.sentCount())
	}

	sender.mu.Lock()
	got := sender.sent[0]
	sender.mu.Unlock()
	if got.Name != "Alice" {
		t.Errorf("sent name = %q, want Alice", got.Name)
	}
	if got.Email != "a@example.com" {
		t.Errorf("sent email = %q, want a@example.com", got.Email)
	}
}

// ---------------------------------------------------------------------------
// TestHandlerSendError
// ---------------------------------------------------------------------------

func TestHandlerSendError(t *testing.T) {
	form := testForm()
	sender := &mockSender{sendErr: errors.New("smtp down")}
	mux := newTestHandlerMux(t, form, sender, nil)

	rec := postJSON(t, mux, "/test",
		`{"name":"Alice","email":"a@example.com","message":"Hello there!"}`)

	if rec.Code != http.StatusInternalServerError {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusInternalServerError)
	}

	var resp contactform.ErrorResponse
	decodeBody(t, rec, &resp)
	if resp.Error != "send_failed" {
		t.Errorf("error = %q, want send_failed", resp.Error)
	}
}

// ---------------------------------------------------------------------------
// TestHandlerNewsletterDoubleOptIn
// ---------------------------------------------------------------------------

// mockConfirmSender records the opt-in links it "mails".
type mockConfirmSender struct {
	*mockSender
	links []string
}

func (m *mockConfirmSender) SendConfirmation(to, link string) error {
	m.mu.Lock()
	defer m.mu.Unlock()
	m.links = append(m.links, link)
	return nil
}

func (m *mockConfirmSender) lastLink() string {
	m.mu.Lock()
	defer m.mu.Unlock()
	if len(m.links) == 0 {
		return ""
	}
	return m.links[len(m.links)-1]
}

// A newsletter signup must stay pending until the confirmation link is
// redeemed; only then does the record land in the log and the owner get
// notified. Replaying the consumed link is a harmless no-op.
func TestHandlerNewsletterDoubleOptIn(t *testing.T) {
	form := testNewsletterForm()
	confirm := &mockConfirmSender{mockSender: &mockSender{}}
	store := &mockStore{}

	dir := t.TempDir()
	h := &ContactHandler{
		trustProxy:   false,
		dataDir:      dir,
		maxBodyBytes: 1 << 20,
		forms:        map[string]*config.Form{form.Path: form},
		senders:      map[string]formSender{form.Path: confirm},
		rateLimits:   map[string]*rateLimiter{form.Path: newTestRateLimiter(form.RateLimit())},
		stores:       map[string]subscriberStorer{form.Path: store},
		pendings: map[string]*storage.PendingStore{
			form.Path: storage.NewPendingStore(filepath.Join(dir, "pending.json"), time.Hour),
		},
	}
	h.stats = newFormStatsRegistry(h.forms)
	mux := http.NewServeMux()
	h.Register(mux)

	rec := postJSON(t, mux, "/test", `{"email":"jane@example.com"}`)
	if rec.Code != http.StatusOK {
		t.Fatalf("signup status = %d, want %d", rec.Code, http.StatusOK)
	}
	if n := confirm.sentCount(); n != 0 {
		t.Errorf("owner notified %d times at signup stage, want 0", n)
	}
	link := confirm.lastLink()
	if link == "" || !strings.Contains(link, "/test/confirm?token=") {
		t.Fatalf("confirmation link not captured: %q", link)
	}
	store.mu.Lock()
	n := len(store.appended)
	store.mu.Unlock()
	if n != 0 {
		t.Fatalf("%d records persisted before confirmation, want 0", n)
	}

	token := link[strings.Index(link, "token=")+len("token="):]
	page := httptest.NewRecorder()
	mux.ServeHTTP(page, httptest.NewRequest(http.MethodGet,
		"/test/confirm?token="+token, nil))
	if page.Code != http.StatusOK {
		t.Fatalf("confirm status = %d, want %d", page.Code, http.StatusOK)
	}
	if !strings.Contains(page.Body.String(), "Subscription confirmed") {
		t.Errorf("unexpected confirmation page:\n%s", page.Body.String())
	}

	store.mu.Lock()
	n, appended := len(store.appended), store.appended
	store.mu.Unlock()
	if n != 1 || appended[0].Email != "jane@example.com" {
		t.Fatalf("log after confirm = %+v, want one jane@example.com record", appended)
	}
	if confirm.sentCount() != 1 {
		t.Errorf("owner notifications after confirm = %d, want 1", confirm.sentCount())
	}

	replay := httptest.NewRecorder()
	mux.ServeHTTP(replay, httptest.NewRequest(http.MethodGet,
		"/test/confirm?token="+token, nil))
	if replay.Code != http.StatusGone {
		t.Fatalf("replay status = %d, want %d", replay.Code, http.StatusGone)
	}
	store.mu.Lock()
	n = len(store.appended)
	store.mu.Unlock()
	if n != 1 {
		t.Errorf("records after replay = %d, want 1", n)
	}

	mrec := httptest.NewRecorder()
	mux.ServeHTTP(mrec, httptest.NewRequest(http.MethodGet, "/metrics", nil))
	var payload struct {
		Totals map[string]int64 `json:"totals"`
	}
	if err := json.Unmarshal(mrec.Body.Bytes(), &payload); err != nil {
		t.Fatalf("decode metrics: %v", err)
	}
	for metric, want := range map[string]int64{
		"confirmation_sent": 1, "confirmed": 1,
		"confirmation_failed": 1,
	} {
		if got := payload.Totals[metric]; got != want {
			t.Errorf("metrics[%s] = %d, want %d", metric, got, want)
		}
	}
}

// When persisting the confirmed record fails, the visitor sees a retry hint
// and the pending entry stays alive so the link can be used again.
func TestHandlerNewsletterConfirmStorageError(t *testing.T) {
	form := testNewsletterForm()
	confirm := &mockConfirmSender{mockSender: &mockSender{}}
	store := &mockStore{appendErr: errors.New("disk full")}

	dir := t.TempDir()
	h := &ContactHandler{
		trustProxy:   false,
		dataDir:      dir,
		maxBodyBytes: 1 << 20,
		forms:        map[string]*config.Form{form.Path: form},
		senders:      map[string]formSender{form.Path: confirm},
		rateLimits:   map[string]*rateLimiter{form.Path: newTestRateLimiter(form.RateLimit())},
		stores:       map[string]subscriberStorer{form.Path: store},
		pendings: map[string]*storage.PendingStore{
			form.Path: storage.NewPendingStore(filepath.Join(dir, "pending.json"), time.Hour),
		},
	}
	h.stats = newFormStatsRegistry(h.forms)
	mux := http.NewServeMux()
	h.Register(mux)

	if rec := postJSON(t, mux, "/test", `{"email":"a@example.com"}`); rec.Code != http.StatusOK {
		t.Fatalf("signup status = %d, want %d", rec.Code, http.StatusOK)
	}
	token := strings.Split(confirm.lastLink(), "token=")[1]

	page := httptest.NewRecorder()
	mux.ServeHTTP(page, httptest.NewRequest(http.MethodGet,
		"/test/confirm?token="+token, nil))
	if page.Code != http.StatusInternalServerError {
		t.Fatalf("confirm status = %d, want %d", page.Code, http.StatusInternalServerError)
	}
	if !h.pendings["/test"].HasToken(token) {
		t.Error("pending entry dropped despite failed persist; retry impossible")
	}
}

func TestCloseIsIdempotent(t *testing.T) {
	h := newTestHandler(testForm(), &mockSender{}, nil)

	h.Close()
	// A second Close must be a no-op, not a panic on a closed channel.
	h.Close()
}

// A full persist/restore round trip: buckets survive a simulated restart,
// stale entries are dropped, and unknown forms are ignored.
func TestRateLimitStateRoundTrip(t *testing.T) {
	dir := t.TempDir()
	cfg := &config.Config{
		DataDir: dir,
		Forms: []config.Form{
			{Name: "c", Path: "/c", Type: "contact", To: "a@b.c",
				SMTP: config.SMTPConfig{Host: "h", Port: 587, User: "u"}},
			{Name: "gone", Path: "/gone", Type: "contact", To: "a@b.c",
				SMTP: config.SMTPConfig{Host: "h", Port: 587, User: "u"}},
		},
	}
	h := New(cfg)
	h.rateLimits["/c"].mu.Lock()
	h.rateLimits["/c"].buckets["1.2.3.4"] = &bucket{tokens: 5, last: time.Now()}
	h.rateLimits["/c"].buckets["stale.ip"] = &bucket{tokens: 5, last: time.Now().Add(-3 * time.Hour)}
	h.rateLimits["/c"].mu.Unlock()
	h.PersistState()

	// Simulate a restart where the "gone" form disappeared from the config.
	cfg.Forms = cfg.Forms[:1]
	h2 := New(cfg)
	if got := len(h2.rateLimits); got != 1 {
		t.Fatalf("restarted handler has %d limiters, want 1", got)
	}
	if len(h2.rateLimits["/c"].buckets) != 1 {
		t.Fatalf("restored bucket count = %d, want 1 (fresh IP only)", len(h2.rateLimits["/c"].buckets))
	}
	if got := h2.rateLimits["/c"].buckets["1.2.3.4"]; got == nil || got.tokens < 4 {
		t.Fatalf("restored bucket = %+v, want ~5 tokens for 1.2.3.4", got)
	}
	if !h2.rateLimits["/c"].allow("1.2.3.4") {
		t.Fatal("restored bucket should still allow a request")
	}
}

// The metrics registry counts what the pipeline reports and /metrics
// serves those counters as JSON. One walkthrough keeps the endpoint honest
// without a dedicated test harness.
func TestMetricsCountAndServe(t *testing.T) {
	form := testForm()
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	rec := postJSON(t, mux, "/test",
		`{"name":"Alice","email":"a@b.com","message":"Hello there!"}`)
	if rec.Code != http.StatusOK {
		t.Fatalf("signup status = %d, want %d", rec.Code, http.StatusOK)
	}
	mrec := httptest.NewRecorder()
	mux.ServeHTTP(mrec, httptest.NewRequest(http.MethodGet, "/metrics", nil))
	if mrec.Code != http.StatusOK {
		t.Fatalf("metrics status = %d, want %d", mrec.Code, http.StatusOK)
	}

	var payload struct {
		Totals map[string]int64            `json:"totals"`
		Forms  map[string]map[string]int64 `json:"forms"`
	}
	if err := json.Unmarshal(mrec.Body.Bytes(), &payload); err != nil {
		t.Fatalf("decode metrics: %v", err)
	}
	fs := payload.Forms["/test"]
	if fs["sent"] != 1 || fs["received"] != 1 || fs["duplicate_signup"] != 0 {
		t.Errorf("per-form counters = %v, want sent=1 received=1", fs)
	}
	if payload.Totals["sent"] != 1 {
		t.Errorf("totals.sent = %d, want 1", payload.Totals["sent"])
	}

	// Unknown metrics and unknown paths are dropped; nil stats are 404.
	h := newTestHandler(testForm(), sender, nil)
	h.bump("/nonexistent", metricSent)
	h.bump("/test", "not_a_metric")
	noreg := &ContactHandler{}
	nr := httptest.NewRecorder()
	noreg.Metrics(nr, httptest.NewRequest(http.MethodGet, "/metrics", nil))
	if nr.Code != http.StatusNotFound {
		t.Errorf("metrics without registry status = %d, want %d", nr.Code, http.StatusNotFound)
	}
}

// With a dedupe-aware store, an address that is already recorded gets the
// same success response without a second confirmation mail.
func TestHandlerNewsletterDuplicateSuppressed(t *testing.T) {
	dir := t.TempDir()
	form := testNewsletterForm()
	store := storage.NewDedupeNewsletterStore(storage.NewNewsletterStore(filepath.Join(dir, "subs.jsonl")))
	if err := store.Append(storage.Subscriber{Email: "jane@example.com"}); err != nil {
		t.Fatal(err)
	}
	confirm := &mockConfirmSender{mockSender: &mockSender{}}
	h := &ContactHandler{
		trustProxy:   false,
		dataDir:      dir,
		maxBodyBytes: 1 << 20,
		forms:        map[string]*config.Form{form.Path: form},
		senders:      map[string]formSender{form.Path: confirm},
		rateLimits:   map[string]*rateLimiter{form.Path: newTestRateLimiter(form.RateLimit())},
		stores:       map[string]subscriberStorer{form.Path: store},
		pendings: map[string]*storage.PendingStore{
			form.Path: storage.NewPendingStore(filepath.Join(dir, "pending.json"), time.Hour),
		},
	}
	h.stats = newFormStatsRegistry(h.forms)
	mux := http.NewServeMux()
	h.Register(mux)

	rec := postJSON(t, mux, "/test", `{"email":"jane@example.com"}`)
	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusOK)
	}
	if len(confirm.links) != 0 {
		t.Errorf("confirmation mails sent = %d, want 0", len(confirm.links))
	}
	n, err := store.Count()
	if err != nil || n != 1 {
		t.Errorf("log lines = %d (err %v), want exactly one record", n, err)
	}

	mrec := httptest.NewRecorder()
	mux.ServeHTTP(mrec, httptest.NewRequest(http.MethodGet, "/metrics", nil))
	var payload struct {
		Totals map[string]int64 `json:"totals"`
	}
	if err := json.Unmarshal(mrec.Body.Bytes(), &payload); err != nil {
		t.Fatalf("decode metrics: %v", err)
	}
	if payload.Totals["duplicate_signup"] != 1 {
		t.Errorf("duplicate_signup counter = %d, want 1",
			payload.Totals["duplicate_signup"])
	}
}

// ---------------------------------------------------------------------------
// Plain HTML form posts: urlencoded and multipart, with and without a
// redirect_url.
// ---------------------------------------------------------------------------

// postForm sends an application/x-www-form-urlencoded POST.
func postForm(handler http.Handler, path string, values url.Values) *httptest.ResponseRecorder {
	req := httptest.NewRequest(http.MethodPost, path, strings.NewReader(values.Encode()))
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	rec := httptest.NewRecorder()
	handler.ServeHTTP(rec, req)
	return rec
}

func TestFormPostRedirectsOnSuccess(t *testing.T) {
	form := testForm()
	form.RedirectURL = "https://example.com/thanks"
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	rec := postForm(mux, "/test", url.Values{
		"name":    {"Jane Doe"},
		"email":   {"jane@example.com"},
		"message": {"Hello, I would like to discuss an engagement."},
	})

	if rec.Code != http.StatusSeeOther {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusSeeOther)
	}
	if loc := rec.Header().Get("Location"); loc != "https://example.com/thanks" {
		t.Errorf("location = %q, want the configured redirect_url", loc)
	}
	if sender.sentCount() != 1 {
		t.Errorf("mails sent = %d, want 1", sender.sentCount())
	}
}

// TestFormPostWithoutRedirectKeepsJSON pins the default: an omitted
// redirect_url keeps the JSON contract for fetch-based frontends.
func TestFormPostWithoutRedirectKeepsJSON(t *testing.T) {
	form := testForm()
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	rec := postForm(mux, "/test", url.Values{
		"name":    {"Jane Doe"},
		"email":   {"jane@example.com"},
		"message": {"Hello, I would like to discuss an engagement."},
	})

	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusOK)
	}
	var resp contactform.Response
	decodeBody(t, rec, &resp)
	if !resp.OK {
		t.Errorf("OK = %v, want true", resp.OK)
	}
}

// TestFormPostValidationStaysJSON documents the error contract: only the
// success answer speaks browser, failures stay machine-readable.
func TestFormPostValidationStaysJSON(t *testing.T) {
	form := testForm()
	form.RedirectURL = "https://example.com/thanks"
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	rec := postForm(mux, "/test", url.Values{
		"name":    {"J"},
		"email":   {"not-an-address"},
		"message": {"hi"},
	})

	if rec.Code != http.StatusBadRequest {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusBadRequest)
	}
	if loc := rec.Header().Get("Location"); loc != "" {
		t.Errorf("location = %q, want none on failure", loc)
	}
	var resp contactform.ErrorResponse
	decodeBody(t, rec, &resp)
	if resp.Error != "validation" || len(resp.Details) == 0 {
		t.Errorf("error = %q with %d details, want validation with details",
			resp.Error, len(resp.Details))
	}
	if sender.sentCount() != 0 {
		t.Errorf("mails sent = %d, want 0", sender.sentCount())
	}
}

func TestFormPostHoneypotSilentRedirect(t *testing.T) {
	form := testForm()
	form.RedirectURL = "https://example.com/thanks"
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	rec := postForm(mux, "/test", url.Values{
		"name":    {"Bot"},
		"email":   {"bot@spam.example"},
		"message": {"buy cheap clicks"},
		"website": {"https://spam.example"},
	})

	if rec.Code != http.StatusSeeOther {
		t.Fatalf("status = %d, want %d (silent accept)", rec.Code, http.StatusSeeOther)
	}
	if sender.sentCount() != 0 {
		t.Errorf("mails sent = %d, want 0", sender.sentCount())
	}
	mrec := httptest.NewRecorder()
	mux.ServeHTTP(mrec, httptest.NewRequest(http.MethodGet, "/metrics", nil))
	var payload struct {
		Totals map[string]int64 `json:"totals"`
	}
	if err := json.Unmarshal(mrec.Body.Bytes(), &payload); err != nil {
		t.Fatalf("decode metrics: %v", err)
	}
	if payload.Totals["honeypot_blocked"] != 1 {
		t.Errorf("honeypot_blocked counter = %d, want 1", payload.Totals["honeypot_blocked"])
	}
}

func TestMultipartFormPostRedirects(t *testing.T) {
	form := testForm()
	form.RedirectURL = "https://example.com/thanks"
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	var buf bytes.Buffer
	mw := multipart.NewWriter(&buf)
	for k, v := range map[string]string{
		"name":    "Jane Doe",
		"email":   "jane@example.com",
		"service": "architecture",
		"message": "Hello, I would like to discuss an engagement.",
	} {
		if err := mw.WriteField(k, v); err != nil {
			t.Fatalf("write field: %v", err)
		}
	}
	if err := mw.Close(); err != nil {
		t.Fatalf("close multipart writer: %v", err)
	}

	req := httptest.NewRequest(http.MethodPost, "/test", &buf)
	req.Header.Set("Content-Type", mw.FormDataContentType())
	rec := httptest.NewRecorder()
	mux.ServeHTTP(rec, req)

	if rec.Code != http.StatusSeeOther {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusSeeOther)
	}
	sent := sender.sent
	if len(sent) != 1 || sent[0].Service != "architecture" {
		t.Errorf("sent = %+v, want one request with the service field", sent)
	}
}

// TestFormPostIgnoresQueryParameters pins the body as the only source:
// a query string cannot smuggle or override payload fields.
func TestFormPostIgnoresQueryParameters(t *testing.T) {
	form := testForm()
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	req := httptest.NewRequest(http.MethodPost,
		"/test?name=Spoof&email=spoof@example.com&message=spoofed", nil)
	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
	rec := httptest.NewRecorder()
	mux.ServeHTTP(rec, req)

	if rec.Code != http.StatusBadRequest {
		t.Fatalf("status = %d, want %d (empty body, empty fields)", rec.Code, http.StatusBadRequest)
	}
	if sender.sentCount() != 0 {
		t.Errorf("mails sent = %d, want 0", sender.sentCount())
	}
}

// ---------------------------------------------------------------------------
// Submission archive: written before the send, so a failed SMTP
// round-trip loses nothing and a failed append blocks the send.
// ---------------------------------------------------------------------------

func newArchivingHandler(t *testing.T, form *config.Form, sender formSender) (*ContactHandler, *mockArchive) {
	t.Helper()
	h := newTestHandler(form, sender, nil)
	archive := &mockArchive{}
	h.archives[form.Path] = archive
	return h, archive
}

func TestArchiveLandsBeforeSend(t *testing.T) {
	form := testForm()
	form.Archive = true
	sender := &mockSender{sendErr: fmt.Errorf("smtp unreachable")}
	h, archive := newArchivingHandler(t, form, sender)
	mux := http.NewServeMux()
	h.Register(mux)

	// The send fails, yet the submission is on disk: nothing is lost.
	rec := postJSON(t, mux, "/test",
		`{"name":"Jane Doe","email":"jane@example.com","message":"Hello there"}`)
	if rec.Code != http.StatusInternalServerError {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusInternalServerError)
	}
	if len(archive.appended) != 1 {
		t.Fatalf("archived = %d, want exactly one record despite the send failure",
			len(archive.appended))
	}
	if got := archive.appended[0]; got.Email != "jane@example.com" || got.Message != "Hello there" {
		t.Errorf("archived = %+v, want the submitted payload", got)
	}

	// A healthy send archives and delivers.
	sender.sendErr = nil
	rec = postJSON(t, mux, "/test",
		`{"name":"Jane Doe","email":"jane@example.com","message":"Hello there"}`)
	if rec.Code != http.StatusOK {
		t.Fatalf("second status = %d, want %d", rec.Code, http.StatusOK)
	}
	if len(archive.appended) != 2 {
		t.Errorf("archived = %d, want 2", len(archive.appended))
	}
}

func TestArchiveAppendFailureBlocksSend(t *testing.T) {
	form := testForm()
	form.Archive = true
	sender := &mockSender{}
	h, archive := newArchivingHandler(t, form, sender)
	archive.appendErr = fmt.Errorf("disk full")
	mux := http.NewServeMux()
	h.Register(mux)

	rec := postJSON(t, mux, "/test",
		`{"name":"Jane Doe","email":"jane@example.com","message":"Hello there"}`)

	if rec.Code != http.StatusInternalServerError {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusInternalServerError)
	}
	var resp contactform.ErrorResponse
	decodeBody(t, rec, &resp)
	if resp.Error != "storage_failed" {
		t.Errorf("error = %q, want storage_failed", resp.Error)
	}
	if sender.sentCount() != 0 {
		t.Errorf("mails sent = %d, want 0 (the record must not split from the mail)",
			sender.sentCount())
	}
}

// TestNoArchiveWithoutTheKey pins the default: New() wires an archive
// store only for a form that asked for one.
func TestNoArchiveWithoutTheKey(t *testing.T) {
	cfg := &config.Config{
		DataDir: t.TempDir(),
		Forms:   []config.Form{*testForm()},
	}
	h := New(cfg)
	defer h.Close()
	if _, ok := h.archives["/test"]; ok {
		t.Errorf("archive store wired for a form without archive = true")
	}
}

// ---------------------------------------------------------------------------
// Auto-reply: a best-effort receipt after the owner mail went out.
// ---------------------------------------------------------------------------

func TestAutoReplyMailedAfterSend(t *testing.T) {
	form := testForm()
	form.AutoReply = true
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	rec := postJSON(t, mux, "/test",
		`{"name":"Jane Doe","email":"jane@example.com","message":"Hello there"}`)

	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusOK)
	}
	if sender.sentCount() != 1 {
		t.Fatalf("owner mails = %d, want 1", sender.sentCount())
	}
	if sender.ackCount() != 1 || sender.acks[0] != "jane@example.com" {
		t.Errorf("acknowledgements = %v, want one to jane@example.com", sender.acks)
	}
}

// TestAutoReplyFailureKeepsSuccess pins the contract: the receipt is
// courtesy, its failure must not turn an accepted submission into an
// error, and the failure lands in its own counter.
func TestAutoReplyFailureKeepsSuccess(t *testing.T) {
	form := testForm()
	form.AutoReply = true
	sender := &mockSender{ackErr: fmt.Errorf("smtp unreachable")}
	mux := newTestHandlerMux(t, form, sender, nil)

	rec := postJSON(t, mux, "/test",
		`{"name":"Jane Doe","email":"jane@example.com","message":"Hello there"}`)

	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusOK)
	}
	if sender.sentCount() != 1 {
		t.Errorf("owner mails = %d, want 1", sender.sentCount())
	}

	mrec := httptest.NewRecorder()
	mux.ServeHTTP(mrec, httptest.NewRequest(http.MethodGet, "/metrics", nil))
	var payload struct {
		Totals map[string]int64 `json:"totals"`
	}
	if err := json.Unmarshal(mrec.Body.Bytes(), &payload); err != nil {
		t.Fatalf("decode metrics: %v", err)
	}
	if payload.Totals["auto_reply_failed"] != 1 {
		t.Errorf("auto_reply_failed counter = %d, want 1", payload.Totals["auto_reply_failed"])
	}
}

// TestNoAutoReplyWithoutTheKey pins the default.
func TestNoAutoReplyWithoutTheKey(t *testing.T) {
	form := testForm()
	sender := &mockSender{}
	mux := newTestHandlerMux(t, form, sender, nil)

	rec := postJSON(t, mux, "/test",
		`{"name":"Jane Doe","email":"jane@example.com","message":"Hello there"}`)
	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusOK)
	}
	if sender.ackCount() != 0 {
		t.Errorf("acknowledgements = %d, want 0", sender.ackCount())
	}
}

// ---------------------------------------------------------------------------
// Metrics bearer token.
// ---------------------------------------------------------------------------

func newTokenedHandler(form *config.Form, token string) http.Handler {
	h := newTestHandler(form, &mockSender{}, nil)
	h.metricsToken = token
	mux := http.NewServeMux()
	h.Register(mux)
	return mux
}

func TestMetricsBearerTokenRequired(t *testing.T) {
	mux := newTokenedHandler(testForm(), "admin")

	req := httptest.NewRequest(http.MethodGet, "/metrics", nil)
	rec := httptest.NewRecorder()
	mux.ServeHTTP(rec, req)
	if rec.Code != http.StatusUnauthorized {
		t.Errorf("status without a header = %d, want %d", rec.Code, http.StatusUnauthorized)
	}
	if got := rec.Header().Get("WWW-Authenticate"); got != `Bearer realm="nuntius metrics"` {
		t.Errorf("www-authenticate = %q, want the bearer challenge", got)
	}

	req = httptest.NewRequest(http.MethodGet, "/metrics", nil)
	req.Header.Set("Authorization", "Bearer wrong")
	rec = httptest.NewRecorder()
	mux.ServeHTTP(rec, req)
	if rec.Code != http.StatusUnauthorized {
		t.Errorf("status with a wrong token = %d, want %d", rec.Code, http.StatusUnauthorized)
	}

	req = httptest.NewRequest(http.MethodGet, "/metrics", nil)
	req.Header.Set("Authorization", "Bearer admin")
	rec = httptest.NewRecorder()
	mux.ServeHTTP(rec, req)
	if rec.Code != http.StatusOK {
		t.Errorf("status with the right token = %d, want %d", rec.Code, http.StatusOK)
	}
}

// TestMetricsOpenWithoutToken pins the default: an unset metrics_token
// keeps the endpoint open, protected at the reverse proxy.
func TestMetricsOpenWithoutToken(t *testing.T) {
	mux := newTokenedHandler(testForm(), "")

	rec := httptest.NewRecorder()
	mux.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/metrics", nil))
	if rec.Code != http.StatusOK {
		t.Errorf("status = %d, want %d", rec.Code, http.StatusOK)
	}
}

// ---------------------------------------------------------------------------
// Telegram: the bell beside the mail. The submission counts as delivered
// when either channel gets through.
// ---------------------------------------------------------------------------

// newTelegramHandler wires the form into a handler with a Telegram
// channel: the fresh mock when notifier is nil, the given one otherwise.
func newTelegramHandler(t *testing.T, form *config.Form, sender formSender, notifier telegramNotifier) (*ContactHandler, *mockTelegram) {
	t.Helper()
	h := newTestHandler(form, sender, nil)
	telegram := &mockTelegram{}
	if notifier != nil {
		h.notifiers[form.Path] = notifier
	} else {
		h.notifiers[form.Path] = telegram
	}
	return h, telegram
}

func telegramTotals(t *testing.T, mux http.Handler) map[string]int64 {
	t.Helper()
	rec := httptest.NewRecorder()
	mux.ServeHTTP(rec, httptest.NewRequest(http.MethodGet, "/metrics", nil))
	var payload struct {
		Totals map[string]int64 `json:"totals"`
	}
	if err := json.Unmarshal(rec.Body.Bytes(), &payload); err != nil {
		t.Fatalf("decode metrics: %v", err)
	}
	return payload.Totals
}

func TestTelegramDeliversBesideTheMail(t *testing.T) {
	form := testForm()
	sender := &mockSender{}
	h, telegram := newTelegramHandler(t, form, sender, nil)
	mux := http.NewServeMux()
	h.Register(mux)

	rec := postJSON(t, mux, "/test",
		`{"name":"Jane Doe","email":"jane@example.com","message":"Hello there"}`)
	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want %d", rec.Code, http.StatusOK)
	}
	if sender.sentCount() != 1 || len(telegram.notes) != 1 {
		t.Errorf("mails = %d, notifications = %d, want one of each",
			sender.sentCount(), len(telegram.notes))
	}
	totals := telegramTotals(t, mux)
	if totals["sent"] != 1 || totals["telegram_failed"] != 0 {
		t.Errorf("sent = %d, telegram_failed = %d, want 1 and 0",
			totals["sent"], totals["telegram_failed"])
	}
}

// TestTelegramSavesAFailedMail pins the useful half of the contract: an
// SMTP outage does not silence the bell, and the caller still sees
// success because the message reached the owner.
func TestTelegramSavesAFailedMail(t *testing.T) {
	form := testForm()
	sender := &mockSender{sendErr: fmt.Errorf("smtp unreachable")}
	h, telegram := newTelegramHandler(t, form, sender, nil)
	mux := http.NewServeMux()
	h.Register(mux)

	rec := postJSON(t, mux, "/test",
		`{"name":"Jane Doe","email":"jane@example.com","message":"Hello there"}`)
	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want %d (the bell rang)", rec.Code, http.StatusOK)
	}
	if len(telegram.notes) != 1 {
		t.Fatalf("notifications = %d, want 1", len(telegram.notes))
	}
	totals := telegramTotals(t, mux)
	if totals["send_failed"] != 1 || totals["sent"] != 0 {
		t.Errorf("send_failed = %d, sent = %d, want 1 and 0",
			totals["send_failed"], totals["sent"])
	}
}

func TestTelegramFailureStillFailsWithoutTheMail(t *testing.T) {
	form := testForm()
	sender := &mockSender{sendErr: fmt.Errorf("smtp unreachable")}
	notifier := &mockTelegram{notifyErr: fmt.Errorf("telegram down")}
	h, _ := newTelegramHandler(t, form, sender, notifier)
	mux := http.NewServeMux()
	h.Register(mux)

	rec := postJSON(t, mux, "/test",
		`{"name":"Jane Doe","email":"jane@example.com","message":"Hello there"}`)
	if rec.Code != http.StatusInternalServerError {
		t.Fatalf("status = %d, want %d (nothing got through)", rec.Code, http.StatusInternalServerError)
	}
	totals := telegramTotals(t, mux)
	if totals["send_failed"] != 1 || totals["telegram_failed"] != 1 {
		t.Errorf("send_failed = %d, telegram_failed = %d, want 1 and 1",
			totals["send_failed"], totals["telegram_failed"])
	}
}

func TestTelegramFailureBesideAMailedSubmission(t *testing.T) {
	form := testForm()
	sender := &mockSender{}
	notifier := &mockTelegram{notifyErr: fmt.Errorf("telegram down")}
	h, _ := newTelegramHandler(t, form, sender, notifier)
	mux := http.NewServeMux()
	h.Register(mux)

	rec := postJSON(t, mux, "/test",
		`{"name":"Jane Doe","email":"jane@example.com","message":"Hello there"}`)
	if rec.Code != http.StatusOK {
		t.Fatalf("status = %d, want %d (the mail went out)", rec.Code, http.StatusOK)
	}
	totals := telegramTotals(t, mux)
	if totals["telegram_failed"] != 1 || totals["sent"] != 1 {
		t.Errorf("telegram_failed = %d, sent = %d, want 1 and 1",
			totals["telegram_failed"], totals["sent"])
	}
}

// TestNoTelegramWithoutTheKey pins the default: New() wires a notifier
// only for a form that carries the telegram table.
func TestNoTelegramWithoutTheKey(t *testing.T) {
	cfg := &config.Config{
		DataDir: t.TempDir(),
		Forms:   []config.Form{*testForm()},
	}
	h := New(cfg)
	defer h.Close()
	if _, ok := h.notifiers["/test"]; ok {
		t.Errorf("telegram notifier wired for a form without the table")
	}
}