package docsite

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

// writeTree writes files (path relative to root, forward slashes) under a
// fresh temp dir and returns it.
func writeTree(t *testing.T, files map[string]string) string {
	t.Helper()
	root := t.TempDir()
	for name, body := range files {
		p := filepath.Join(root, filepath.FromSlash(name))
		if err := os.MkdirAll(filepath.Dir(p), 0o755); err != nil {
			t.Fatal(err)
		}
		if err := os.WriteFile(p, []byte(body), 0o644); err != nil {
			t.Fatal(err)
		}
	}
	return root
}

func problemLines(problems []Problem) []string {
	var out []string
	for _, p := range problems {
		out = append(out, p.String())
	}
	return out
}

const fixtureSite = `title: Acme
description: Acme docs.
sections:
  - name: setup
    title: Setup
  - name: api
    title: API reference
`

func page(title, section string, order int, body string) string {
	return "---\ntitle: " + title + "\ndescription: " + title + " page.\nsection: " + section +
		"\norder: " + strconv.Itoa(order) + "\n---\n# " + title + "\n\n" + body
}

func TestSlugIDs(t *testing.T) {
	ids := newSlugIDs()
	for _, tc := range []struct{ in, want string }{
		{"Install the CLI", "install-the-cli"},
		{"Install the CLI", "install-the-cli-1"},
		{"Install the CLI", "install-the-cli-2"},
		{"snake_case and dash-case", "snake_case-and-dash-case"},
		{"What's new? (v2.0)", "whats-new-v20"},
		{"`bonfire.Call` usage", "bonfirecall-usage"},
		{"Zażółć gęślą", "zażółć-gęślą"},
		{"!!!", "section"},
	} {
		if got := string(ids.Generate([]byte(tc.in), 0)); got != tc.want {
			t.Errorf("Generate(%q) = %q, want %q", tc.in, got, tc.want)
		}
	}
	ids.Put([]byte("custom"))
	if got := string(ids.Generate([]byte("Custom"), 0)); got != "custom-1" {
		t.Errorf("after Put, Generate(Custom) = %q, want custom-1", got)
	}
}

func TestReadmeIngestion(t *testing.T) {
	files := map[string]string{
		"docs/site.yaml":         fixtureSite,
		"docs/index.md":          page("Acme docs", "index", 0, "Read [alpha](../modules/alpha/README.md#usage).\n"),
		"docs/setup/start.md":    page("Start", "setup", 10, "## First steps\n\nText.\n"),
		"modules/alpha/alpha.go": "package alpha\n",
		"modules/alpha/README.md": "# alpha\n\nAlpha does one thing well.\n\n## Usage\n\n" +
			"See [delta](../delta/README.md#api) and [start](../../docs/setup/start.md).\n",
		"modules/beta/beta.go":        "package beta\n",
		"modules/gamma/gamma_test.go": "package gamma\n",
		"modules/delta/delta.go":      "package delta\n",
		"modules/delta/README.md":     "# delta\n\nDelta does another thing.\n\n## API\n\nText.\n",
	}
	root := writeTree(t, files)

	pages, problems, err := Pages(Options{Root: root})
	if err != nil {
		t.Fatal(err)
	}
	want := "modules/beta: readme: package has Go files but no README.md"
	if got := problemLines(problems); !slices.Equal(got, []string{want}) {
		t.Fatalf("problems = %q, want [%q]", got, want)
	}
	var urls []string
	for _, p := range pages {
		urls = append(urls, p.URL)
	}
	if !slices.Equal(urls, []string{"index", "setup/start", "api/alpha", "api/delta"}) {
		t.Fatalf("reading order = %v", urls)
	}
	alpha := pages[2]
	if alpha.Title != "alpha" || alpha.Description != "Alpha does one thing well." || alpha.Section != "api" ||
		alpha.Module != "alpha" || alpha.Source != "modules/alpha/README.md" {
		t.Fatalf("alpha page = %+v", alpha)
	}

	if err := os.WriteFile(filepath.Join(root, "modules/beta/README.md"), []byte("# beta\n\nBeta.\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	out := filepath.Join(t.TempDir(), "site")
	res, problems, err := Build(Options{Root: root, Out: out})
	if err != nil || len(problems) > 0 {
		t.Fatalf("Build: %v %q", err, problemLines(problems))
	}
	if res.Pages != 5 {
		t.Fatalf("pages = %d, want 5", res.Pages)
	}
	read := func(name string) string {
		t.Helper()
		b, err := os.ReadFile(filepath.Join(out, name))
		if err != nil {
			t.Fatal(err)
		}
		return string(b)
	}
	html := read("api/alpha.html")
	for _, want := range []string{`href="/api/delta.html#api"`, `href="/setup/start.html"`, `<h2 id="usage">Usage</h2>`} {
		if !strings.Contains(html, want) {
			t.Errorf("api/alpha.html missing %s", want)
		}
	}
	if strings.Contains(html, "<h1>alpha</h1>\n<p class=\"lead\">Alpha does one thing well.</p>\n<p>Alpha does") {
		t.Error("summary line rendered twice")
	}
	md := read("api/alpha.md")
	if !strings.HasPrefix(md, "# alpha\n\n> Alpha does one thing well.\n\n## Usage\n") ||
		!strings.Contains(md, "(/api/delta.md#api)") || !strings.Contains(md, "(/setup/start.md)") {
		t.Errorf("api/alpha.md = %q", md)
	}
	if idx := read("index.html"); !strings.Contains(idx, `href="/api/alpha.html#usage"`) {
		t.Error("index.html does not link the rewritten module README")
	}
	search := read("search-index.json")
	if !strings.Contains(search, `{"p":2,"a":"usage","h":"Usage","x":"See delta and start."}`) {
		t.Errorf("search index missing the alpha Usage entry: %s", search)
	}
}