package library

import (
	"context"
	"math"
	"path/filepath"
	"testing"

	"github.com/jackc/pgx/v5/pgtype"

	"git.fabledsword.com/bvandeusen/minstrel/internal/db/dbq"
)

func TestGainDBAndLinearPeak(t *testing.T) {
	f := func(v float32) *float32 { return &v }
	for _, c := range []struct {
		lufs, want float32
	}{
		{-18, 0},        // at the reference: no change
		{-9.5, -8.5},    // a loud master is turned down
		{-23.456, 5.46}, // a quiet one up, to 0.01 dB
	} {
		if got := GainDB(f(c.lufs)); got == nil || *got != c.want {
			t.Errorf("GainDB(%v) = %v, want %v", c.lufs, got, c.want)
		}
	}
	if GainDB(nil) != nil {
		t.Errorf("GainDB(nil) is not nil")
	}
	for _, c := range []struct {
		dbtp, want float32
	}{
		{0, 1},         // full scale
		{-6.0206, 0.5}, // half amplitude
		{1.2, 1.1482},  // an inter-sample over, above 1.0
	} {
		got := LinearPeak(f(c.dbtp))
		if got == nil || math.Abs(float64(*got-c.want)) > 0.0001 {
			t.Errorf("LinearPeak(%v) = %v, want %v", c.dbtp, got, c.want)
		}
	}
	if LinearPeak(nil) != nil {
		t.Errorf("LinearPeak(nil) is not nil")
	}
}

func TestReplayGainForTracks_Integration(t *testing.T) {
	pool := newPool(t)
	ctx := context.Background()
	q := dbq.New(pool)
	dir := t.TempDir()

	measured, album, artist := seedTrack(t, pool, filepath.Join(dir, "measured.mp3"))
	add := func(name string) dbq.Track {
		t.Helper()
		tr, err := q.UpsertTrack(ctx, dbq.UpsertTrackParams{
			Title: name, AlbumID: album.ID, ArtistID: artist.ID,
			DurationMs: 1000, FilePath: filepath.Join(dir, name+".mp3"), FileSize: 100, FileFormat: "mp3",
		})
		if err != nil {
			t.Fatalf("track %s: %v", name, err)
		}
		return tr
	}
	older := add("older")
	unmeasured := add("unmeasured")
	f := func(v float32) *float32 { return &v }
	for _, m := range []struct {
		tr      dbq.Track
		lufs    float32
		version int16
	}{
		{measured, -12, loudnessVersion},
		// A measurement by an older method is still a better gain than none.
		{older, -20, loudnessVersion - 1},
	} {
		if err := q.UpsertTrackLoudness(ctx, dbq.UpsertTrackLoudnessParams{
			TrackID: m.tr.ID, IntegratedLufs: f(m.lufs), TruePeakDbtp: f(-1), AnalysisVersion: m.version,
		}); err != nil {
			t.Fatalf("seed: %v", err)
		}
	}

	gains, err := ReplayGainForTracks(ctx, q, []pgtype.UUID{measured.ID, older.ID, unmeasured.ID})
	if err != nil {
		t.Fatalf("lookup: %v", err)
	}
	if g := gains[measured.ID]; g.TrackGain == nil || *g.TrackGain != -6 || g.TrackPeak == nil {
		t.Errorf("measured track gains = %+v, want track gain -6 with a peak", g)
	}
	if g := gains[older.ID]; g.TrackGain == nil || *g.TrackGain != 2 {
		t.Errorf("older-version track gains = %+v, want track gain 2", g)
	}
	if _, ok := gains[unmeasured.ID]; ok {
		t.Errorf("unmeasured track has an entry; absent means no adjustment")
	}
	// No album value yet (none computed): the album pair is absent.
	if g := gains[measured.ID]; g.AlbumGain != nil || g.AlbumPeak != nil {
		t.Errorf("album pair present before album loudness exists: %+v", g)
	}

	if err := q.UpsertAlbumLoudness(ctx, dbq.UpsertAlbumLoudnessParams{
		AlbumID: album.ID, IntegratedLufs: f(-14), TruePeakDbtp: f(-0.5),
		TracksTotal: 3, TracksSettled: 3, InputsDigest: "x",
	}); err != nil {
		t.Fatalf("seed album: %v", err)
	}
	gains, err = ReplayGainForTracks(ctx, q, []pgtype.UUID{unmeasured.ID})
	if err != nil {
		t.Fatalf("lookup: %v", err)
	}
	if g := gains[unmeasured.ID]; g.TrackGain != nil || g.AlbumGain == nil || *g.AlbumGain != -4 || g.AlbumPeak == nil {
		t.Errorf("unmeasured track on a leveled album = %+v, want only the album pair (gain -4)", g)
	}
	byAlbum, err := ReplayGainForAlbums(ctx, q, []pgtype.UUID{album.ID})
	if err != nil {
		t.Fatalf("album lookup: %v", err)
	}
	if g := byAlbum[album.ID]; g.AlbumGain == nil || *g.AlbumGain != -4 || g.TrackGain != nil {
		t.Errorf("album gains = %+v, want album gain -4 and no track pair", g)
	}
}