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

package app

import (
	"fmt"
	"io"
	"log/slog"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"strings"
	"testing"

	"sourcedock.dev/petrbalvin/volumen/internal/config"
	"sourcedock.dev/petrbalvin/volumen/internal/store"
)

// BenchmarkServer drives the wired handler over real HTTP: a list, a
// single post, a tag feed and the sitemap, against a corpus the size of a
// site that has been running for a few years. It is also the workload the
// PGO profile is recorded from, which is why it exercises the whole chain
// rather than one function.
func BenchmarkServer(b *testing.B) {
	const posts = 500
	dir := b.TempDir()
	content := filepath.Join(dir, "posts")
	if err := os.MkdirAll(content, 0o755); err != nil {
		b.Fatalf("mkdir: %v", err)
	}
	for i := range posts {
		body := fmt.Sprintf(`+++
title = "Post %d"
slug = "post-%d"
date = 2026-01-%02d
lang = "en"
tags = ["go", "bench"]
series = "Bench"
series_order = %d
+++

## Section

A paragraph with **markup**, a [link](https://example.com) and enough
words to make the renderer do real work: %s

- one
- two
- three
`, i, i, i%28+1, i, strings.Repeat("lorem ipsum dolor sit amet ", 40))
		path := filepath.Join(content, fmt.Sprintf("post-%d.md", i))
		if err := os.WriteFile(path, []byte(body), 0o644); err != nil {
			b.Fatalf("write: %v", err)
		}
	}
	cfg := config.Defaults()
	cfg.ContentDir = content
	cfg.UsersFile = filepath.Join(dir, "users.toml")
	cfg.Admin.SessionKey = strings.Repeat("k", 64)
	cfg.Site.BaseURL = "https://site.example"
	cfg.API.RateLimit = 0
	srv, err := New(cfg, store.New(store.Options{ContentDir: content, DefaultLang: "en", RevisionLimit: 10}))
	if err != nil {
		b.Fatalf("New: %v", err)
	}
	// The access line each request writes is noise inside a benchmark.
	previous := slog.Default()
	slog.SetDefault(slog.New(slog.NewTextHandler(io.Discard, nil)))
	b.Cleanup(func() { slog.SetDefault(previous) })

	server := httptest.NewServer(srv.Handler())
	defer server.Close()

	targets := []string{
		"/api/volumen/posts?limit=20",
		"/api/volumen/posts/post-250",
		"/api/volumen/tags",
		"/api/volumen/tags/go/feed.json",
		"/api/volumen/sitemap.xml",
	}
	client := server.Client()
	b.ResetTimer()
	for i := 0; b.Loop(); i++ {
		resp, err := client.Get(server.URL + targets[i%len(targets)])
		if err != nil {
			b.Fatalf("get: %v", err)
		}
		if _, err := io.Copy(io.Discard, resp.Body); err != nil {
			b.Fatalf("read: %v", err)
		}
		resp.Body.Close()
		if resp.StatusCode != http.StatusOK {
			b.Fatalf("%s: status %d", targets[i%len(targets)], resp.StatusCode)
		}
	}
}