package render

import (
	"bytes"
	"context"
	"encoding/json"
	"encoding/xml"
	"flag"
	"fmt"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"git.pablomurad.com/pablo/patchwork/internal/config"
	"git.pablomurad.com/pablo/patchwork/internal/engine"
	"git.pablomurad.com/pablo/patchwork/internal/store"
)

var update = flag.Bool("update", false, "rewrite testdata/golden")

// scenario builds a small moonflower-like site with a known history:
// a page with two revisions (the second amended), one page never revised,
// and one page whose only revision was retracted.
func scenario(t *testing.T) (*store.Store, *config.Config) {
	t.Helper()
	st, err := store.Open(filepath.Join(t.TempDir(), "pw.db"))
	if err != nil {
		t.Fatal(err)
	}
	t.Cleanup(func() { st.Close() })

	cfg := config.Default()
	cfg.Site = config.Site{
		Title: "Moon Flower Society", BaseURL: "https://moonflowersociety.org", Timezone: "America/Sao_Paulo",
		Author: "Pablo Murad", TagAuthority: "moonflowersociety.org,2026",
		PageURL: "/idea/{slug}", VersionURL: "/idea/{slug}/v/{n}", HistoryURL: "/idea/{slug}/history",
		Feeds: config.SiteFeeds{Atom: "/revisions.atom", JSON: "/revisions.json", PageAtom: "/idea/{slug}/revisions.atom", PageJSON: "/idea/{slug}/revisions.json"},
	}
	cfg.Source.Slug = "datestrip-slugify"

	e, err := engine.New(st, cfg)
	if err != nil {
		t.Fatal(err)
	}
	now := time.Date(2026, 10, 1, 15, 0, 0, 0, time.UTC)
	e.Now = func() time.Time { return now }
	uid := 0
	e.NewUID = func() string { uid++; return fmt.Sprintf("p_test%04d", uid) }

	ctx := context.Background()
	put := func(path, body string) {
		t.Helper()
		if _, err := e.Ingest(ctx, engine.Observation{Path: path, Raw: []byte(body)}, false); err != nil {
			t.Fatal(err)
		}
		now = now.Add(24 * time.Hour)
	}

	remote := "2026-06-21-remote-work.md"
	put(remote, "---\ntitle: Remote work\nmaturity: seed\n---\n# Remote work\n\nThe hybrid model is the worst of both worlds.\n\nSmall teams should pick one place.\n")
	put("notes.md", "# Notes\n\nA page that never changes.\n")
	put(remote, "---\ntitle: Remote work\nmaturity: sprout\nrevision: Two years in, I changed my mind.\nrevision_kind: position\n---\n# Remote work\n\nThe hybrid model works when the team agrees on fixed office days.\n\nSmall teams should pick one place.\n")
	put(remote, "---\ntitle: Remote work\nmaturity: sprout\nrevision: Added what I'd tell a new team <and> why.\nrevision_kind: expansion\n---\n# Remote work\n\nThe hybrid model works when the team agrees on fixed office days.\n\nSmall teams should pick one place.\n\n- meet in person every month\n- write things down\n")
	put(remote, "---\ntitle: Remote work\nmaturity: sprout\nrevision: Added what I'd tell a new team & why.\nrevision_kind: expansion\n---\n# Remote work\n\nThe hybrid model works when the team agrees on fixed office days.\n\nSmall teams should pick one place.\n\n- meet in person every month\n- write things down\n")

	put("draft.md", "A draft.\n")
	put("draft.md", "---\nrevision: Oops, published by mistake.\n---\nA draft with a secret.\n")
	p, err := st.PageByPath(ctx, "folder", "draft.md")
	if err != nil {
		t.Fatal(err)
	}
	if err := e.Retract(ctx, p.ID, 2, false); err != nil {
		t.Fatal(err)
	}
	return st, cfg
}

func build(t *testing.T) *Tree {
	t.Helper()
	st, cfg := scenario(t)
	tree, err := Build(context.Background(), st, cfg)
	if err != nil {
		t.Fatal(err)
	}
	return tree
}

// TestTreeGolden pins every published byte. Review a diff in testdata/golden
// like a diff in the API: it's what sites and feed readers will see.
func TestTreeGolden(t *testing.T) {
	tree := build(t)
	root := filepath.Join("testdata", "golden")
	if *update {
		os.RemoveAll(root)
	}
	seen := map[string]bool{}
	for _, p := range tree.Paths() {
		seen[p] = true
		path := filepath.Join(root, filepath.FromSlash(p))
		body := tree.Files[p].Body
		if *update {
			os.MkdirAll(filepath.Dir(path), 0o755)
			if err := os.WriteFile(path, body, 0o644); err != nil {
				t.Fatal(err)
			}
			continue
		}
		want, err := os.ReadFile(path)
		if err != nil {
			t.Errorf("%s: %v (run with -update)", p, err)
			continue
		}
		if !bytes.Equal(bytes.ReplaceAll(want, []byte("\r\n"), []byte("\n")), body) {
			t.Errorf("%s differs from golden; got:\n%s", p, body)
		}
	}
	filepath.WalkDir(root, func(path string, d os.DirEntry, err error) error {
		if err == nil && !d.IsDir() {
			rel, _ := filepath.Rel(root, path)
			if !seen[filepath.ToSlash(rel)] {
				t.Errorf("golden file %s is no longer produced", rel)
			}
		}
		return nil
	})
}

func TestRetractedRevisionIsGone(t *testing.T) {
	tree := build(t)
	for p, f := range tree.Files {
		if strings.Contains(string(f.Body), "secret") && !strings.Contains(p, "/versions/1") {
			// Version 1 of draft.md never had the secret; any mention of it
			// means the retracted text leaked.
			t.Errorf("retracted text published in %s", p)
		}
	}
	if _, ok := tree.Files["api/v1/pages/draft/versions/2.json"]; ok {
		t.Error("retracted version is still served")
	}
}

func TestAtomRoundTrip(t *testing.T) {
	tree := build(t)
	var f atomFeed
	if err := xml.Unmarshal(tree.Files["feeds/revisions.atom"].Body, &f); err != nil {
		t.Fatal(err)
	}
	if len(f.Entries) != 2 {
		t.Fatalf("entries %d", len(f.Entries))
	}
	ids := map[string]bool{}
	for _, e := range f.Entries {
		if ids[e.ID] {
			t.Errorf("duplicate id %s", e.ID)
		}
		ids[e.ID] = true
		if !strings.HasPrefix(e.ID, "tag:moonflowersociety.org,2026:patchwork/") {
			t.Errorf("id %s", e.ID)
		}
		if _, err := time.Parse(time.RFC3339, e.Updated); err != nil {
			t.Errorf("updated %q: %v", e.Updated, err)
		}
	}
	// The amended revision keeps its id and moves its updated time.
	newest := f.Entries[0]
	if newest.Published == newest.Updated || !strings.Contains(newest.Content.Body, "&amp; why") {
		t.Errorf("amended entry %+v", newest)
	}
	self := ""
	for _, l := range f.Links {
		if l.Rel == "self" {
			self = l.Href
		}
	}
	if self != "https://moonflowersociety.org/revisions.atom" {
		t.Errorf("self link %q", self)
	}
}

func TestJSONFeedShape(t *testing.T) {
	tree := build(t)
	var f map[string]any
	if err := json.Unmarshal(tree.Files["feeds/pages/remote-work.json"].Body, &f); err != nil {
		t.Fatal(err)
	}
	if f["version"] != "https://jsonfeed.org/version/1.1" || f["feed_url"] != "https://moonflowersociety.org/idea/remote-work/revisions.json" {
		t.Fatalf("feed %v", f)
	}
	items := f["items"].([]any)
	if len(items) != 2 {
		t.Fatalf("items %d", len(items))
	}
}

func TestTextWrapsAndColors(t *testing.T) {
	st, cfg := scenario(t)
	m, err := Load(context.Background(), st, cfg)
	if err != nil {
		t.Fatal(err)
	}
	out := m.TextRevisions(m.Revisions, TextOptions{Width: 48, Color: true})
	if !strings.Contains(out, "\x1b[32m") || !strings.Contains(out, "\x1b[31m") {
		t.Error("colored output should mark insertions and deletions")
	}
	for _, line := range strings.Split(stripANSI(out), "\n") {
		// A single unbreakable word (a URL) may overflow: cutting it would
		// break copy and paste.
		if visibleWidth(line) > 48 && strings.Contains(strings.TrimSpace(line), " ") {
			t.Errorf("line wider than 48: %q", line)
		}
	}
	plain := m.TextRevisions(m.Revisions, TextOptions{Width: 80})
	if strings.Contains(plain, "\x1b[") || !strings.Contains(plain, "\n  - ") || !strings.Contains(plain, "\n  + ") {
		t.Errorf("plain output should mark changes without ANSI:\n%s", plain)
	}
}

func stripANSI(s string) string {
	var b strings.Builder
	for i := 0; i < len(s); i++ {
		if s[i] == 0x1b {
			for i < len(s) && s[i] != 'm' {
				i++
			}
			continue
		}
		b.WriteByte(s[i])
	}
	return b.String()
}