package library

import (
	"testing"

	"github.com/dhowden/tag"
)

// stubMeta is a minimal tag.Metadata used to feed the dhowden mbz extractor
// the same Raw()/Format() shape its real parsers produce. The other interface
// methods return zero values — the extractor only branches on Format and
// iterates Raw().
type stubMeta struct {
	format tag.Format
	raw    map[string]interface{}
}

func (s stubMeta) Format() tag.Format          { return s.format }
func (s stubMeta) FileType() tag.FileType      { return tag.UnknownFileType }
func (s stubMeta) Title() string               { return "" }
func (s stubMeta) Album() string               { return "" }
func (s stubMeta) Artist() string              { return "" }
func (s stubMeta) AlbumArtist() string         { return "" }
func (s stubMeta) Composer() string            { return "" }
func (s stubMeta) Year() int                   { return 0 }
func (s stubMeta) Genre() string               { return "" }
func (s stubMeta) Track() (int, int)           { return 0, 0 }
func (s stubMeta) Disc() (int, int)            { return 0, 0 }
func (s stubMeta) Picture() *tag.Picture       { return nil }
func (s stubMeta) Lyrics() string              { return "" }
func (s stubMeta) Comment() string             { return "" }
func (s stubMeta) Raw() map[string]interface{} { return s.raw }

func TestExtractMBIDs_Vorbis(t *testing.T) {
	// dhowden lowercases all Vorbis comment keys at parse time.
	m := stubMeta{
		format: tag.VORBIS,
		raw: map[string]interface{}{
			"musicbrainz_albumid":  "abc",
			"musicbrainz_artistid": "def",
		},
	}
	a, ar := extractMBIDs(m)
	if a != "abc" || ar != "def" {
		t.Errorf("got (%q, %q), want (\"abc\", \"def\")", a, ar)
	}
}

func TestExtractMBIDs_ID3v2(t *testing.T) {
	// dhowden stores TXXX frames under bare "TXXX"/"TXXX_N" keys with
	// *tag.Comm values whose Description holds the Picard tag name.
	m := stubMeta{
		format: tag.ID3v2_4,
		raw: map[string]interface{}{
			"TXXX": &tag.Comm{
				Description: "MusicBrainz Album Id",
				Text:        "abc-123",
			},
			"TXXX_0": &tag.Comm{
				Description: "MusicBrainz Artist Id",
				Text:        "def-456",
			},
		},
	}
	a, ar := extractMBIDs(m)
	if a != "abc-123" || ar != "def-456" {
		t.Errorf("got (%q, %q), want (\"abc-123\", \"def-456\")", a, ar)
	}
}

func TestExtractMBIDs_MP4(t *testing.T) {
	// dhowden stores freeform iTunes atoms under their bare sub-name.
	// mbz.Extract maps the human-readable form back to its lowercase key.
	m := stubMeta{
		format: tag.MP4,
		raw: map[string]interface{}{
			"MusicBrainz Album Id":  "abc",
			"MusicBrainz Artist Id": "def",
		},
	}
	a, ar := extractMBIDs(m)
	if a != "abc" || ar != "def" {
		t.Errorf("got (%q, %q), want (\"abc\", \"def\")", a, ar)
	}
}

func TestExtractMBIDs_MissingTagsReturnEmpty(t *testing.T) {
	m := stubMeta{format: tag.VORBIS, raw: map[string]interface{}{}}
	a, ar := extractMBIDs(m)
	if a != "" || ar != "" {
		t.Errorf("got (%q, %q), want empty", a, ar)
	}
}

func TestExtractMBIDs_VorbisUppercaseKeysMiss(t *testing.T) {
	// Regression guard: real dhowden never produces uppercase Vorbis
	// keys. If a future change starts looking up "MUSICBRAINZ_ALBUMID"
	// directly, this test must keep returning empty so we don't
	// silently re-introduce the v0 bug where every album skipped.
	m := stubMeta{
		format: tag.VORBIS,
		raw: map[string]interface{}{
			"MUSICBRAINZ_ALBUMID":  "wrong-case",
			"MUSICBRAINZ_ARTISTID": "wrong-case",
		},
	}
	a, ar := extractMBIDs(m)
	if a != "" || ar != "" {
		t.Errorf("uppercase Vorbis keys must not match dhowden output; got (%q, %q)", a, ar)
	}
}

func TestExtractMBIDs_ID3v2StripsTrailingNUL(t *testing.T) {
	// dhowden's readTextWithDescrFrame leaves the ID3v2.4 frame-
	// terminator NUL on TXXX values. Postgres rejects NULs in text
	// columns (SQLSTATE 22021), so we must strip them.
	m := stubMeta{
		format: tag.ID3v2_4,
		raw: map[string]interface{}{
			"TXXX": &tag.Comm{
				Description: "MusicBrainz Album Id",
				Text:        "abc-123\x00",
			},
			"TXXX_0": &tag.Comm{
				Description: "MusicBrainz Artist Id",
				Text:        "def-456\x00",
			},
		},
	}
	a, ar := extractMBIDs(m)
	if a != "abc-123" || ar != "def-456" {
		t.Errorf("got (%q, %q), want trailing NUL stripped", a, ar)
	}
}

func TestExtractMBIDs_ID3v2MultiValueTakesFirst(t *testing.T) {
	// Some Picard configs emit multi-value TXXX:MusicBrainz Artist Id
	// for collaborations, NUL-separated. Minstrel uses the primary
	// release artist for MBCAA, so first wins.
	m := stubMeta{
		format: tag.ID3v2_4,
		raw: map[string]interface{}{
			"TXXX": &tag.Comm{
				Description: "MusicBrainz Artist Id",
				Text:        "primary-mbid\x00collab-mbid",
			},
		},
	}
	_, ar := extractMBIDs(m)
	if ar != "primary-mbid" {
		t.Errorf("got %q, want %q", ar, "primary-mbid")
	}
}

func TestCleanMBID_OnlyNULReturnsEmpty(t *testing.T) {
	// Defensive: a TXXX value that is purely NULs (or empty after
	// trimming) must round-trip to empty so the caller skips the row
	// instead of writing a NUL-only string to Postgres.
	if got := cleanMBID("\x00\x00"); got != "" {
		t.Errorf("got %q, want empty", got)
	}
	if got := cleanMBID(""); got != "" {
		t.Errorf("got %q, want empty", got)
	}
}