package service

import (
	"context"
	"database/sql"
	"errors"
	"fmt"
	"os"
	"path/filepath"
	"strings"
	"syscall"
	"testing"
	"time"

	"vidarchive/internal/config"
	"vidarchive/internal/models"
)

func TestSanitizeDirName(t *testing.T) {
	tests := []struct{ in, want string }{
		{"normal title", "normal title"},
		{"a/b:c*d?e\"f<g>h|i", "a-b-c-d-e-f-g-h-i"},
		{"  trimmed  ", "trimmed"},
		{"", "untitled"},
		{"///", "---"},
	}
	for _, tc := range tests {
		if got := sanitizeDirName(tc.in); got != tc.want {
			t.Errorf("sanitizeDirName(%q) = %q, want %q", tc.in, got, tc.want)
		}
	}
}

func TestUniqueDir(t *testing.T) {
	base := t.TempDir()
	svc := &DownloadService{}

	first := svc.uniqueDir(base, "item")
	if filepath.Base(first) != "item" {
		t.Errorf("first uniqueDir = %q, want .../item", first)
	}
	if err := os.MkdirAll(first, 0755); err != nil {
		t.Fatal(err)
	}
	second := svc.uniqueDir(base, "item")
	if filepath.Base(second) != "item-1" {
		t.Errorf("second uniqueDir = %q, want .../item-1", second)
	}
	if err := os.MkdirAll(second, 0755); err != nil {
		t.Fatal(err)
	}
	third := svc.uniqueDir(base, "item")
	if filepath.Base(third) != "item-2" {
		t.Errorf("third uniqueDir = %q, want .../item-2", third)
	}
}

func TestDeriveItemName(t *testing.T) {
	svc := &DownloadService{}
	itemDir := t.TempDir()

	// info.json title wins and is sanitized.
	infoPath := filepath.Join(itemDir, "info.json")
	if err := os.WriteFile(infoPath, []byte(`{"title":"Cool: Video"}`), 0644); err != nil {
		t.Fatal(err)
	}
	bigName := "big.mp4"
	if err := os.WriteFile(filepath.Join(itemDir, bigName), []byte("xxxxxxxxxx"), 0644); err != nil {
		t.Fatal(err)
	}
	media := []os.DirEntry{dirEntry(t, itemDir, bigName)}
	if got := svc.deriveItemName(itemDir, readInfoJSON(infoPath), media); got != "Cool- Video" {
		t.Errorf("deriveItemName with info.json = %q, want %q", got, "Cool- Video")
	}

	// Without info.json, falls back to the largest media file's stem.
	small := "small.mp4"
	if err := os.WriteFile(filepath.Join(itemDir, small), []byte("x"), 0644); err != nil {
		t.Fatal(err)
	}
	media = []os.DirEntry{dirEntry(t, itemDir, small), dirEntry(t, itemDir, bigName)}
	if got := svc.deriveItemName(itemDir, infoJSON{}, media); got != "big" {
		t.Errorf("deriveItemName fallback = %q, want %q (largest file stem)", got, "big")
	}
}

func dirEntry(t *testing.T, dir, name string) os.DirEntry {
	t.Helper()
	entries, err := os.ReadDir(dir)
	if err != nil {
		t.Fatal(err)
	}
	for _, e := range entries {
		if e.Name() == name {
			return e
		}
	}
	t.Fatalf("dir entry %q not found", name)
	return nil
}

func TestParseFormatJSON(t *testing.T) {
	data := []byte(`{
		"id": "vid",
		"formats": [
			{"format_id": "18", "ext": "mp4", "resolution": "640x360", "fps": 30, "vcodec": "avc1", "acodec": "mp4a", "format_note": "360p"},
			{"format_id": "137", "ext": "mp4", "width": 1920, "height": 1080, "fps": 60, "vcodec": "avc1", "acodec": "none", "filesize": 1048576, "format_note": "1080p"},
			{"format_id": "233", "ext": "m4a", "resolution": "audio only", "vcodec": "none", "acodec": "mp4a", "audio_channels": 2, "format_note": "audio"}
		]
	}`)
	formats, err := parseFormatJSON(data)
	if err != nil {
		t.Fatalf("parseFormatJSON: %v", err)
	}
	if len(formats) != 3 {
		t.Fatalf("expected 3 formats, got %d: %+v", len(formats), formats)
	}
	if formats[0].ID != "18" || formats[0].Ext != "mp4" || formats[0].Resolution != "640x360" {
		t.Errorf("format[0] = %+v", formats[0])
	}
	if formats[0].FPS != "30" {
		t.Errorf("format[0] fps = %q, want 30", formats[0].FPS)
	}
	// Resolution is derived from width/height when no resolution string is present.
	if formats[1].Resolution != "1920x1080" {
		t.Errorf("format[1] resolution = %q, want 1920x1080", formats[1].Resolution)
	}
	if formats[1].FileSize != "1.0MiB" {
		t.Errorf("format[1] filesize = %q, want 1.0MiB", formats[1].FileSize)
	}
	// Audio-only format: codec falls back to acodec and channels are populated.
	if formats[2].Codec != "mp4a" {
		t.Errorf("format[2] codec = %q, want mp4a", formats[2].Codec)
	}
	if formats[2].Channels != "2" {
		t.Errorf("format[2] channels = %q, want 2", formats[2].Channels)
	}
}

func TestParseFormatJSONPlaylistFallback(t *testing.T) {
	// A playlist dump exposes formats under the first entry, not at the top level.
	data := []byte(`{"_type":"playlist","entries":[{"id":"a","formats":[{"format_id":"18","ext":"mp4"}]}]}`)
	formats, err := parseFormatJSON(data)
	if err != nil {
		t.Fatalf("parseFormatJSON: %v", err)
	}
	if len(formats) != 1 || formats[0].ID != "18" {
		t.Fatalf("expected 1 format from entry fallback, got %+v", formats)
	}
}

// TestImportItemDir exercises the full import: media + info.json + subtitles get
// sorted into a named item directory with a marker. Uses ffmpeg to produce real
// media so the mimetype-based classification in importItemDir matches.
func TestImportItemDir(t *testing.T) {
	requireFFmpeg(t)

	libDir := t.TempDir()
	svc := &DownloadService{cfg: &config.Config{LibraryDir: libDir, FFprobePath: "ffprobe"}}

	src := t.TempDir()
	makeTestVideo(t, filepath.Join(src, "raw.mp4"))
	if err := os.WriteFile(filepath.Join(src, "info.json"), []byte(`{"title":"My Clip"}`), 0644); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(filepath.Join(src, "raw.en.srt"), []byte("1\n00:00:00,000 --> 00:00:01,000\nhi\n"), 0644); err != nil {
		t.Fatal(err)
	}

	if err := svc.importItemDir(context.Background(), "https://example.com/v", src, libDir, "", "-f bestvideo+bestaudio"); err != nil {
		t.Fatalf("importItemDir: %v", err)
	}

	targetDir := filepath.Join(libDir, "My Clip")
	if _, err := os.Stat(filepath.Join(targetDir, itemMarkerName)); err != nil {
		t.Errorf("marker not created: %v", err)
	}
	if _, err := os.Stat(filepath.Join(targetDir, "info.json")); err != nil {
		t.Errorf("info.json not moved: %v", err)
	}
	if _, err := os.Stat(filepath.Join(targetDir, "raw.mp4")); err != nil {
		t.Errorf("media not moved: %v", err)
	}
	if _, err := os.Stat(filepath.Join(targetDir, subtitlesDirName, "raw.en.srt")); err != nil {
		t.Errorf("subtitle not moved into subtitles dir: %v", err)
	}

	// The marker should record the source URL and a probed per-file duration
	// (the test video is 3s), so the library never has to probe at serve time.
	markerData, _ := os.ReadFile(filepath.Join(targetDir, itemMarkerName))
	if want := "https://example.com/v"; !strings.Contains(string(markerData), want) {
		t.Errorf("marker missing source url %q: %s", want, markerData)
	}
	if !strings.Contains(string(markerData), "file_durations") || !strings.Contains(string(markerData), "raw.mp4") {
		t.Errorf("marker missing probed per-file duration: %s", markerData)
	}
	if want := "-f bestvideo+bestaudio"; !strings.Contains(string(markerData), want) {
		t.Errorf("marker missing yt-dlp flags %q: %s", want, markerData)
	}
}

func TestCheckReservedFlags(t *testing.T) {
	cases := []struct {
		name         string
		flags        string
		subscription bool
		wantErr      bool
	}{
		{"empty", "", false, false},
		{"harmless", "--no-playlist --write-thumbnail", false, false},
		{"output short", "-o foo.mp4", false, true},
		{"output long", "--output foo.mp4", false, true},
		{"output equals form", "--output=foo.mp4", false, true},
		{"paths short", "-P /tmp", false, true},
		{"cookies", "--cookies x.txt", false, true},
		{"cookies inverse", "--no-cookies", false, true},
		// Subscription-only reserved flags pass for normal downloads...
		{"skip-download non-sub", "--skip-download", false, false},
		{"write-info-json non-sub", "--write-info-json", false, false},
		// ...but are rejected for subscription runs (and their inverses).
		{"skip-download sub", "--skip-download", true, true},
		{"no-skip-download sub", "--no-skip-download", true, true},
		{"write-info-json sub", "--write-info-json", true, true},
		{"no-write-info-json sub", "--no-write-info-json", true, true},
		{"download-archive sub", "--download-archive a.txt", true, true},
		// The "--flag=value" spelling names the same option as "--flag value",
		// for the subscription-only table as well as the base one.
		{"download-archive equals form sub", "--download-archive=a.txt", true, true},
		// Base reserved flags still apply to subscriptions.
		{"output sub", "-o x", true, true},
	}
	for _, tc := range cases {
		t.Run(tc.name, func(t *testing.T) {
			err := checkReservedFlags(tc.flags, tc.subscription)
			if tc.wantErr != (err != nil) {
				t.Errorf("checkReservedFlags(%q, %v) error = %v, wantErr %v", tc.flags, tc.subscription, err, tc.wantErr)
			}
		})
	}
}

func TestImportDownloadedItemsRejectsOutputTraversal(t *testing.T) {
	libDir := t.TempDir()
	svc := &DownloadService{
		cfg:        &config.Config{LibraryDir: libDir},
		librarySvc: NewLibraryService(libDir, "ffmpeg", "ffprobe"),
	}

	// A temp download dir with one item subdir.
	tempDir := t.TempDir()
	itemDir := filepath.Join(tempDir, "item-00001")
	if err := os.MkdirAll(itemDir, 0755); err != nil {
		t.Fatal(err)
	}

	d := &models.Download{
		URL:       "u",
		OutputDir: sql.NullString{String: "../escape", Valid: true},
	}
	if _, err := svc.importDownloadedItems(context.Background(), d, tempDir, "", ""); err == nil {
		t.Error("expected path-traversal output dir to be rejected")
	}
}

// A download deleted while its items are being imported must stop, not keep
// filling the library with items whose queue row no longer exists.
func TestImportDownloadedItemsStopsOnCancel(t *testing.T) {
	requireFFmpeg(t)

	libDir := t.TempDir()
	svc := &DownloadService{
		cfg:        &config.Config{LibraryDir: libDir, FFprobePath: "ffprobe"},
		librarySvc: NewLibraryService(libDir, "ffmpeg", "ffprobe"),
	}

	tempDir := t.TempDir()
	for _, name := range []string{"item-00001", "item-00002"} {
		itemDir := filepath.Join(tempDir, name)
		if err := os.MkdirAll(itemDir, 0755); err != nil {
			t.Fatal(err)
		}
		makeTestVideo(t, filepath.Join(itemDir, "raw.mp4"))
	}

	ctx, cancel := context.WithCancel(context.Background())
	cancel()

	imported, err := svc.importDownloadedItems(ctx, &models.Download{URL: "u"}, tempDir, "", "")
	if !errors.Is(err, context.Canceled) {
		t.Errorf("error = %v, want context.Canceled", err)
	}
	if imported != 0 {
		t.Errorf("imported = %d, want 0", imported)
	}
	entries, err := os.ReadDir(libDir)
	if err != nil {
		t.Fatal(err)
	}
	if len(entries) != 0 {
		t.Errorf("library got %d entries, want 0", len(entries))
	}
}

// A cancel part-way through a playlist must stop at an item boundary: the items
// already imported stay, and no half-written directory is left behind.
func TestImportDownloadedItemsStopsBetweenItems(t *testing.T) {
	requireFFmpeg(t)

	libDir := t.TempDir()
	svc := &DownloadService{
		cfg:        &config.Config{LibraryDir: libDir, FFprobePath: "ffprobe"},
		librarySvc: NewLibraryService(libDir, "ffmpeg", "ffprobe"),
	}

	tempDir := t.TempDir()
	for i, name := range []string{"item-00001", "item-00002", "item-00003"} {
		itemDir := filepath.Join(tempDir, name)
		if err := os.MkdirAll(itemDir, 0755); err != nil {
			t.Fatal(err)
		}
		makeTestVideo(t, filepath.Join(itemDir, "raw.mp4"))
		info := fmt.Sprintf(`{"id":"v%d","title":"Clip %d"}`, i+1, i+1)
		if err := os.WriteFile(filepath.Join(itemDir, "clip.info.json"), []byte(info), 0644); err != nil {
			t.Fatal(err)
		}
	}

	// Cancel as soon as the first item lands, so the second boundary check trips.
	ctx, cancel := context.WithCancel(context.Background())
	stop := make(chan struct{})
	go func() {
		defer close(stop)
		for {
			if _, err := os.Stat(filepath.Join(libDir, "Clip 1", itemMarkerName)); err == nil {
				cancel()
				return
			}
			time.Sleep(2 * time.Millisecond)
		}
	}()

	imported, err := svc.importDownloadedItems(ctx, &models.Download{URL: "u"}, tempDir, "", "")
	<-stop
	cancel()

	if !errors.Is(err, context.Canceled) {
		t.Fatalf("error = %v, want context.Canceled", err)
	}
	if imported < 1 || imported > 2 {
		t.Errorf("imported = %d, want the cancel to land after 1 or 2 items", imported)
	}

	// Whatever was imported must be complete: an item dir without a marker means
	// the import stopped half-way through writing it.
	entries, err := os.ReadDir(libDir)
	if err != nil {
		t.Fatal(err)
	}
	if len(entries) != imported {
		t.Errorf("library has %d dirs but reported %d imported", len(entries), imported)
	}
	for _, entry := range entries {
		marker := filepath.Join(libDir, entry.Name(), itemMarkerName)
		if _, err := os.Stat(marker); err != nil {
			t.Errorf("item %q left without a marker: %v", entry.Name(), err)
		}
	}
}

// Overwrite mode replaces the existing copy of a video in place instead of
// adding a second directory for it.
func TestImportItemDirOverwriteReplacesExisting(t *testing.T) {
	requireFFmpeg(t)

	libDir := t.TempDir()
	svc := &DownloadService{
		cfg:        &config.Config{LibraryDir: libDir, FFprobePath: "ffprobe"},
		librarySvc: NewLibraryService(libDir, "ffmpeg", "ffprobe"),
	}

	// First import establishes the item.
	first := t.TempDir()
	makeTestVideo(t, filepath.Join(first, "raw.mp4"))
	if err := os.WriteFile(filepath.Join(first, "clip.info.json"), []byte(`{"id":"vid1","title":"Old Title"}`), 0644); err != nil {
		t.Fatal(err)
	}
	if err := svc.importItemDir(context.Background(), "https://example.com/v", first, libDir, "overwrite", ""); err != nil {
		t.Fatalf("first import: %v", err)
	}
	if err := os.WriteFile(filepath.Join(libDir, "Old Title", "stale.txt"), []byte("gone"), 0644); err != nil {
		t.Fatal(err)
	}

	// Second import of the same video id, now retitled upstream.
	second := t.TempDir()
	makeTestVideo(t, filepath.Join(second, "raw.mp4"))
	if err := os.WriteFile(filepath.Join(second, "clip.info.json"), []byte(`{"id":"vid1","title":"New Title"}`), 0644); err != nil {
		t.Fatal(err)
	}
	if err := svc.importItemDir(context.Background(), "https://example.com/v", second, libDir, "overwrite", ""); err != nil {
		t.Fatalf("second import: %v", err)
	}

	entries, err := os.ReadDir(libDir)
	if err != nil {
		t.Fatal(err)
	}
	if len(entries) != 1 || entries[0].Name() != "New Title" {
		var names []string
		for _, e := range entries {
			names = append(names, e.Name())
		}
		t.Fatalf("library = %v, want exactly [New Title]", names)
	}
	if _, err := os.Stat(filepath.Join(libDir, "New Title", "stale.txt")); err == nil {
		t.Error("the replaced item kept a file from the old copy")
	}
}

// Without overwrite mode the same video is imported again beside the first, so
// the guard above is really the thing preventing duplicates.
func TestImportItemDirWithoutOverwriteKeepsBoth(t *testing.T) {
	requireFFmpeg(t)

	libDir := t.TempDir()
	svc := &DownloadService{
		cfg:        &config.Config{LibraryDir: libDir, FFprobePath: "ffprobe"},
		librarySvc: NewLibraryService(libDir, "ffmpeg", "ffprobe"),
	}

	for i := 0; i < 2; i++ {
		src := t.TempDir()
		makeTestVideo(t, filepath.Join(src, "raw.mp4"))
		if err := os.WriteFile(filepath.Join(src, "clip.info.json"), []byte(`{"id":"vid1","title":"Same"}`), 0644); err != nil {
			t.Fatal(err)
		}
		if err := svc.importItemDir(context.Background(), "https://example.com/v", src, libDir, "", ""); err != nil {
			t.Fatalf("import %d: %v", i, err)
		}
	}

	entries, err := os.ReadDir(libDir)
	if err != nil {
		t.Fatal(err)
	}
	if len(entries) != 2 {
		t.Errorf("library has %d dirs, want 2 (Same and Same-1)", len(entries))
	}
}

// moveFile falls back to copy+delete when the source and destination are on
// different filesystems, which is the normal case for a temp dir on tmpfs and a
// library on disk. /dev/shm is a second tmpfs mount, so a rename across it
// really does return EXDEV.
func TestMoveFileCrossDeviceFallback(t *testing.T) {
	dstDir, err := os.MkdirTemp("/dev/shm", "vidarchive-move-")
	if err != nil {
		t.Skipf("no second filesystem available for a cross-device move: %v", err)
	}
	defer os.RemoveAll(dstDir)

	srcDir := t.TempDir()
	if sameDevice(t, srcDir, dstDir) {
		t.Skip("temp dir and /dev/shm are on the same filesystem")
	}

	src := filepath.Join(srcDir, "clip.mp4")
	content := []byte("not really a video, but the bytes must survive")
	if err := os.WriteFile(src, content, 0640); err != nil {
		t.Fatal(err)
	}

	// Confirm the fallback is actually what gets exercised.
	dst := filepath.Join(dstDir, "clip.mp4")
	if err := os.Rename(src, dst); !errors.Is(err, syscall.EXDEV) {
		t.Skipf("rename across the two dirs did not report EXDEV: %v", err)
	}

	if err := moveFile(src, dst); err != nil {
		t.Fatalf("moveFile: %v", err)
	}

	got, err := os.ReadFile(dst)
	if err != nil {
		t.Fatalf("read destination: %v", err)
	}
	if string(got) != string(content) {
		t.Errorf("destination content = %q, want %q", got, content)
	}
	info, err := os.Stat(dst)
	if err != nil {
		t.Fatal(err)
	}
	if info.Mode().Perm() != 0640 {
		t.Errorf("destination mode = %v, want 0640", info.Mode().Perm())
	}
	if _, err := os.Stat(src); !os.IsNotExist(err) {
		t.Error("source still exists after a successful move")
	}
}

// A move that cannot even read the source must not leave a destination behind.
func TestMoveFileMissingSourceLeavesNoDestination(t *testing.T) {
	dir := t.TempDir()
	dst := filepath.Join(dir, "dst.mp4")

	if err := moveFile(filepath.Join(dir, "missing.mp4"), dst); err == nil {
		t.Fatal("expected an error moving a file that does not exist")
	}
	if _, err := os.Stat(dst); !os.IsNotExist(err) {
		t.Error("destination was created for a failed move")
	}
}

func sameDevice(t *testing.T, a, b string) bool {
	t.Helper()
	var sa, sb syscall.Stat_t
	if err := syscall.Stat(a, &sa); err != nil {
		t.Fatal(err)
	}
	if err := syscall.Stat(b, &sb); err != nil {
		t.Fatal(err)
	}
	return sa.Dev == sb.Dev
}