// Copyright (c) 2026 Petr Balvín <opensource@petrbalvin.org> (https://petrbalvin.org)
// SPDX-License-Identifier: PolyForm-Noncommercial-1.0.0

package config

import (
	"os"
	"path/filepath"
	"slices"
	"strings"
	"testing"
)

func writableConfig(t *testing.T) string {
	t.Helper()
	dir := t.TempDir()
	path := filepath.Join(dir, "config.toml")
	content := filepath.Join(dir, "posts")
	users := filepath.Join(dir, "users.toml")
	body := "content_dir = \"" + content + "\"\n" +
		"users_file = \"" + users + "\"\n" +
		"\n[server]\n" +
		"host = \"::1\"\n" +
		"port = 8080\n" +
		"env = \"production\"\n" +
		"trust_proxy = true\n" +
		"\n[site]\n" +
		"base_url = \"https://site.example\"\n" +
		"language = \"cs\"\n"
	if err := os.WriteFile(path, []byte(body), 0o600); err != nil {
		t.Fatalf("write config: %v", err)
	}
	return path
}

func TestLoadMergesDefaults(t *testing.T) {
	cfg, err := Load(writableConfig(t), Overrides{Port: -1})
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if cfg.Server.Host != "::1" || cfg.Server.Port != 8080 || cfg.Server.Env != EnvProduction {
		t.Fatalf("server section wrong: %s %d %s", cfg.Server.Host, cfg.Server.Port, cfg.Server.Env)
	}
	if !cfg.Server.TrustProxy {
		t.Fatal("trust_proxy not loaded")
	}
	if cfg.Site.Title != DefaultSiteTitle {
		t.Fatalf("default title missing: %q", cfg.Site.Title)
	}
	if cfg.Site.Language != "cs" {
		t.Fatalf("language = %q", cfg.Site.Language)
	}
	if cfg.Admin.SessionTTL != DefaultSessionTTL {
		t.Fatalf("session_ttl = %d", cfg.Admin.SessionTTL)
	}
	if cfg.RevisionLimit != DefaultRevisionLimit {
		t.Fatalf("revision_limit = %d", cfg.RevisionLimit)
	}
}

func TestLoadMissingFileUsesDefaults(t *testing.T) {
	cfg, err := Load(filepath.Join(t.TempDir(), "nope.toml"), Overrides{Port: -1})
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if cfg.Server.Host != DefaultHost || cfg.Server.Port != DefaultPort {
		t.Fatalf("defaults not applied: %s %d", cfg.Server.Host, cfg.Server.Port)
	}
}

func TestLoadRejectsInvalidToml(t *testing.T) {
	path := filepath.Join(t.TempDir(), "config.toml")
	if err := os.WriteFile(path, []byte("not = valid = toml"), 0o600); err != nil {
		t.Fatalf("write: %v", err)
	}
	if _, err := Load(path, Overrides{Port: -1}); err == nil {
		t.Fatal("want parse error")
	}
}

// A root key written below [server] belongs to that table, where nothing
// reads it. The loader names the key and the fix rather than silently
// falling back to the default path.
func TestLoadRejectsAFoldedRootKey(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "config.toml")
	body := "[server]\nhost = \"::1\"\ncontent_dir = \"" + filepath.Join(dir, "posts") + "\"\n"
	if err := os.WriteFile(path, []byte(body), 0o600); err != nil {
		t.Fatalf("write: %v", err)
	}
	_, err := Load(path, Overrides{Port: -1})
	if err == nil {
		t.Fatal("want an error for a root key below a table header")
	}
	if !strings.Contains(err.Error(), "content_dir") ||
		!strings.Contains(err.Error(), "[table] header") {
		t.Fatalf("error does not name the key and the fix: %v", err)
	}
}

// The shipped template is a valid configuration as written: loading it
// and validating it (with the data paths pointed at a writable directory)
// is what every deployment does after copying config.toml.example.
func TestShippedTemplateLoads(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "config.toml")
	if err := os.WriteFile(path, []byte(Template), 0o600); err != nil {
		t.Fatalf("write template: %v", err)
	}
	cfg, err := Load(path, Overrides{
		Port:       -1,
		ContentDir: filepath.Join(dir, "posts"),
		UsersFile:  filepath.Join(dir, "users.toml"),
	})
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if err := cfg.Validate(); err != nil {
		t.Fatalf("Validate: %v", err)
	}
	// The template's site block must carry the same defaults the code
	// serves, so a deployment with no config file and one that copies the
	// example present the same site.
	if cfg.Site.Title != DefaultSiteTitle || cfg.Site.Description != DefaultSiteDescription {
		t.Fatalf("template defaults = %q, %q; want %q, %q",
			cfg.Site.Title, cfg.Site.Description, DefaultSiteTitle, DefaultSiteDescription)
	}
	// A fresh template leaves the session key empty: the server generates
	// its own secret rather than the config carrying one.
	if cfg.Admin.SessionKey != "" {
		t.Fatalf("template session_key should default empty, got %q", cfg.Admin.SessionKey)
	}
}

// A missing configuration file moves the state under the user's home:
// that is what lets a plain `volumen serve` on a fresh machine run
// without root, and the overrides still win over it.
func TestMissingFileUsesUserStatePaths(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	t.Setenv("XDG_DATA_HOME", "")
	t.Setenv("XDG_CONFIG_HOME", "")
	cfg, err := Load(filepath.Join(home, "nope", "config.toml"), Overrides{Port: -1})
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	want := filepath.Join(home, ".local", "share", "volumen")
	if cfg.ContentDir != filepath.Join(want, "posts") || cfg.UsersFile != filepath.Join(want, "users.toml") {
		t.Fatalf("paths = %q %q, want under %q", cfg.ContentDir, cfg.UsersFile, want)
	}

	// XDG_DATA_HOME wins over ~/.local/share when set.
	data := t.TempDir()
	t.Setenv("XDG_DATA_HOME", data)
	cfg, err = Load(filepath.Join(home, "nope", "config.toml"), Overrides{Port: -1})
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if cfg.ContentDir != filepath.Join(data, "volumen", "posts") {
		t.Fatalf("XDG_DATA_HOME ignored: %q", cfg.ContentDir)
	}

	// An explicit override beats the user default.
	cfg, err = Load(filepath.Join(home, "nope", "config.toml"), Overrides{
		Port:       -1,
		ContentDir: "/srv/posts",
		UsersFile:  "/srv/users.toml",
	})
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if cfg.ContentDir != "/srv/posts" || cfg.UsersFile != "/srv/users.toml" {
		t.Fatalf("override lost: %q %q", cfg.ContentDir, cfg.UsersFile)
	}
}

// Without --config the file is chosen in order: /etc, then the per-user
// path, then /etc again so a fresh machine loads the defaults.
func TestResolveConfigPathOrder(t *testing.T) {
	home := t.TempDir()
	t.Setenv("HOME", home)
	t.Setenv("XDG_CONFIG_HOME", "")
	userCfg := filepath.Join(home, ".config", "volumen", "config.toml")

	// Nothing exists: the system path is named so Load reports defaults.
	if got := ResolveConfigPath(); got != DefaultPath {
		t.Fatalf("with no files = %q, want %q", got, DefaultPath)
	}
	if err := os.MkdirAll(filepath.Dir(userCfg), 0o755); err != nil {
		t.Fatalf("mkdir: %v", err)
	}
	if err := os.WriteFile(userCfg, []byte("port = 9091\n"), 0o600); err != nil {
		t.Fatalf("write: %v", err)
	}
	if got := ResolveConfigPath(); got != userCfg {
		t.Fatalf("user config not found: %q", got)
	}
}

func TestOverrides(t *testing.T) {
	cfg, err := Load(filepath.Join(t.TempDir(), "x.toml"), Overrides{
		Host:       "127.0.0.1",
		Port:       1234,
		ContentDir: "/srv/posts",
		UsersFile:  "/srv/users.toml",
	})
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if cfg.Server.Host != "127.0.0.1" || cfg.Server.Port != 1234 {
		t.Fatalf("host/port override failed: %s %d", cfg.Server.Host, cfg.Server.Port)
	}
	if cfg.ContentDir != "/srv/posts" || cfg.UsersFile != "/srv/users.toml" {
		t.Fatal("path overrides failed")
	}
}

func TestValidateOK(t *testing.T) {
	cfg, err := Load(writableConfig(t), Overrides{Port: -1})
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if err := cfg.Validate(); err != nil {
		t.Fatalf("Validate: %v", err)
	}
}

func TestValidateFailures(t *testing.T) {
	dir := t.TempDir()
	base := func(mutate func(*Config)) *Config {
		cfg, err := Load(filepath.Join(dir, "none.toml"), Overrides{Port: -1})
		if err != nil {
			t.Fatalf("Load: %v", err)
		}
		if mutate != nil {
			mutate(cfg)
		}
		return cfg
	}
	cases := []struct {
		name string
		cfg  *Config
		frag string
	}{
		{"host", base(func(c *Config) { c.Server.Host = "" }), "[server].host"},
		{"host_not_an_address", base(func(c *Config) { c.Server.Host = "localhost" }), "[server].host"},
		{"port", base(func(c *Config) { c.Server.Port = 0 }), "[server].port"},
		{"env", base(func(c *Config) { c.Server.Env = "staging" }), "[server].env"},
		{"log_format", base(func(c *Config) { c.Server.LogFormat = "xml" }), "log_format"},
		{"trusted_proxies", base(func(c *Config) { c.Server.TrustedProxies = []string{"not a prefix"} }), "trusted_proxies"},
		{"base_url", base(func(c *Config) { c.Site.BaseURL = "notaurl" }), "base_url"},
		{"fediverse", base(func(c *Config) { c.Site.FediverseCreator = "nope" }), "fediverse_creator"},
		{"webhook", base(func(c *Config) { c.Webhooks = []Webhook{{URL: "ftp://x"}} }), "webhooks"},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			err := tc.cfg.Validate()
			if err == nil {
				t.Fatal("want error")
			}
			if !strings.Contains(err.Error(), tc.frag) {
				t.Fatalf("error %q does not mention %q", err, tc.frag)
			}
		})
	}

	t.Run("session_ttl", func(t *testing.T) {
		cfg := base(func(c *Config) { c.Admin.SessionTTL = 0 })
		if err := cfg.Validate(); err == nil || !strings.Contains(err.Error(), "session_ttl") {
			t.Fatalf("err = %v", err)
		}
	})
	t.Run("password lengths", func(t *testing.T) {
		cfg := base(func(c *Config) {
			c.Admin.MinPasswordLength = 20
			c.Admin.MaxPasswordLength = 10
		})
		if err := cfg.Validate(); err == nil {
			t.Fatal("want error")
		}
	})
	t.Run("rate limit", func(t *testing.T) {
		cfg := base(func(c *Config) { c.API.RateLimit = -1 })
		if err := cfg.Validate(); err == nil {
			t.Fatal("want error")
		}
	})

}

// The config file an operator writes for a reverse proxy decodes its
// trusted proxy list, empty list included: this is the shape documented
// in the template and what a production deployment relies on.
func TestTrustedProxiesParse(t *testing.T) {
	dir := t.TempDir()
	path := filepath.Join(dir, "config.toml")
	body := "content_dir = \"" + filepath.Join(dir, "posts") + "\"\n" +
		"users_file = \"" + filepath.Join(dir, "users.toml") + "\"\n" +
		"\n[server]\n" +
		"host = \"::1\"\n" +
		"trust_proxy = true\n" +
		"trusted_proxies = [\"::1\", \"127.0.0.1\"]\n"
	if err := os.WriteFile(path, []byte(body), 0o600); err != nil {
		t.Fatalf("write: %v", err)
	}
	cfg, err := Load(path, Overrides{Port: PortUnset})
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	want := []string{"::1", "127.0.0.1"}
	if !slices.Equal(cfg.Server.TrustedProxies, want) {
		t.Fatalf("trusted_proxies = %v, want %v", cfg.Server.TrustedProxies, want)
	}

	emptyPath := filepath.Join(dir, "empty.toml")
	emptyBody := "content_dir = \"" + filepath.Join(dir, "posts") + "\"\n" +
		"users_file = \"" + filepath.Join(dir, "users.toml") + "\"\n" +
		"\n[server]\n" +
		"host = \"::1\"\n" +
		"trusted_proxies = []\n"
	if err := os.WriteFile(emptyPath, []byte(emptyBody), 0o600); err != nil {
		t.Fatalf("write: %v", err)
	}
	empty, err := Load(emptyPath, Overrides{Port: PortUnset})
	if err != nil {
		t.Fatalf("Load empty: %v", err)
	}
	if len(empty.Server.TrustedProxies) != 0 {
		t.Fatalf("empty list parsed as %v", empty.Server.TrustedProxies)
	}
}

// The example shipped in the repository is the embedded template, so the
// two cannot drift: the documentation points at both.
func TestExampleMatchesTemplate(t *testing.T) {
	raw, err := os.ReadFile(filepath.Join("..", "..", "config.toml.example"))
	if err != nil {
		t.Fatalf("read config.toml.example: %v", err)
	}
	if string(raw) != Template {
		t.Fatal("config.toml.example differs from config.Template")
	}
}

func TestAuditLogPathAndScheduler(t *testing.T) {
	cfg, err := Load(filepath.Join(t.TempDir(), "x.toml"), Overrides{Port: -1})
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if cfg.AuditLog != "" {
		t.Fatal("audit log should default to disabled")
	}
	if cfg.Scheduler.Enabled || cfg.Scheduler.Interval != DefaultSchedulerInterval {
		t.Fatal("scheduler defaults wrong")
	}
	cfg.AuditLog = "/var/log/volumen-audit.log"
	cfg.Scheduler = Scheduler{Enabled: true, Interval: 60}
	if cfg.AuditLog != "/var/log/volumen-audit.log" {
		t.Fatalf("audit log = %q", cfg.AuditLog)
	}
	if !cfg.Scheduler.Enabled || cfg.Scheduler.Interval != 60 {
		t.Fatal("scheduler config wrong")
	}
}

// A hook is on unless the file turns it off, which is the reason the
// field is a pointer: an omitted key must not read as false.
func TestWebhookDefaults(t *testing.T) {
	path := filepath.Join(t.TempDir(), "hooks.toml")
	body := "[[webhooks]]\nurl = \"https://example.com/one\"\n\n" +
		"[[webhooks]]\nurl = \"https://example.com/two\"\nenabled = false\n"
	if err := os.WriteFile(path, []byte(body), 0o600); err != nil {
		t.Fatalf("write: %v", err)
	}
	cfg, err := Load(path, Overrides{Port: -1})
	if err != nil {
		t.Fatalf("Load: %v", err)
	}
	if len(cfg.Webhooks) != 2 {
		t.Fatalf("webhooks = %v", cfg.Webhooks)
	}
	if !cfg.Webhooks[0].Delivers() {
		t.Fatal("an omitted enabled key disabled the hook")
	}
	if cfg.Webhooks[1].Delivers() {
		t.Fatal("an explicit false left the hook enabled")
	}
}