package library

import (
	"bytes"
	"context"
	"io"
	"log/slog"
	"path/filepath"
	"sort"
	"strings"
	"testing"
	"time"

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

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

func TestCoveredByDismissal(t *testing.T) {
	dismissed := []map[string]struct{}{{"a": {}, "b": {}, "c": {}}}
	for _, tc := range []struct {
		name    string
		members []string
		want    bool
	}{
		{"the same set", []string{"a", "b", "c"}, true},
		{"a subset of it", []string{"a", "b"}, true},
		// A new copy joining is new evidence: ask again.
		{"a superset of it", []string{"a", "b", "c", "d"}, false},
		{"overlapping only in part", []string{"a", "d"}, false},
		{"unrelated", []string{"x", "y"}, false},
	} {
		if got := coveredByDismissal(tc.members, dismissed); got != tc.want {
			t.Errorf("%s: coveredByDismissal = %v, want %v", tc.name, got, tc.want)
		}
	}
}

// TestDuplicateSweep_Integration pins what the sweep proposes, what it leaves out,
// and how re-sweeping treats a dismissal and a proposal that no longer holds.
func TestDuplicateSweep_Integration(t *testing.T) {
	pool := newPool(t)
	ctx := context.Background()
	q := dbq.New(pool)
	dir := t.TempDir()
	logger := slog.New(slog.NewTextHandler(io.Discard, nil))

	// seedTrack's own track has no fingerprint row: it must be absent from the
	// report, not grouped with every other track lacking one.
	_, album, artist := seedTrack(t, pool, filepath.Join(dir, "unfingerprinted.mp3"))
	hash := func(b byte) []byte { return bytes.Repeat([]byte{b}, 32) }
	add := func(name string, durationMs int32, sum []byte, print []int32) string {
		t.Helper()
		tr, err := q.UpsertTrack(ctx, dbq.UpsertTrackParams{
			Title: name, AlbumID: album.ID, ArtistID: artist.ID, DurationMs: durationMs,
			FilePath: filepath.Join(dir, name+".mp3"), FileSize: 100, FileFormat: "mp3",
		})
		if err != nil {
			t.Fatalf("track %s: %v", name, err)
		}
		if err := q.UpsertTrackFingerprint(ctx, dbq.UpsertTrackFingerprintParams{
			TrackID: tr.ID, AudioStreamSha256: sum, Chromaprint: print, FingerprintVersion: fingerprintVersion,
			ChromaprintLengthSec: defaultChromaprintLengthSec,
		}); err != nil {
			t.Fatalf("fingerprint %s: %v", name, err)
		}
		return syncpkg.FormatUUID(tr.ID)
	}
	key := func(ids ...string) string {
		sorted := append([]string(nil), ids...)
		sort.Strings(sorted)
		return strings.Join(sorted, ",")
	}

	recording := randomPrint(200, printLen)
	onAlbum := add("recording-album", 240000, hash(1), recording)
	onCompilation := add("recording-compilation", 241000, hash(2), withBitNoise(recording, 0.05, 201))
	www1 := add("www-01", 215000, hash(9), randomPrint(210, printLen))
	www2 := add("www-02", 215000, hash(9), randomPrint(210, printLen))
	// Near-identical duration to the recording, different audio.
	add("different-song", 240500, hash(3), randomPrint(220, printLen))
	// Identical to the album copy, but its file is gone: nothing to compare.
	missing := add("missing-copy", 240000, hash(4), recording)
	if _, err := pool.Exec(ctx, "UPDATE tracks SET missing_since = now() WHERE file_path LIKE '%missing-copy.mp3'"); err != nil {
		t.Fatalf("mark missing: %v", err)
	}

	type stored struct {
		tier, status string
	}
	groups := func() map[string]stored {
		t.Helper()
		rows, err := pool.Query(ctx, `SELECT member_key, tier, status FROM duplicate_groups`)
		if err != nil {
			t.Fatalf("read groups: %v", err)
		}
		defer rows.Close()
		out := map[string]stored{}
		for rows.Next() {
			var k string
			var s stored
			if err := rows.Scan(&k, &s.tier, &s.status); err != nil {
				t.Fatalf("scan group: %v", err)
			}
			out[k] = s
		}
		return out
	}

	// 1. A page size of one forces the keyset cursor across every candidate.
	res, err := runDuplicateSweep(ctx, pool, logger, DefaultFingerprintSettings, 1)
	if err != nil {
		t.Fatalf("first sweep: %v", err)
	}
	// Five tracks carry a chromaprint and a present file.
	if res.Candidates != 5 || res.Groups != 2 || res.Proposed != 2 {
		t.Fatalf("first sweep = %+v, want 5 candidates, 2 groups, 2 proposed", res)
	}
	acousticKey, exactKey := key(onAlbum, onCompilation), key(www1, www2)
	got := groups()
	want := map[string]stored{
		acousticKey: {"acoustic", "pending"},
		exactKey:    {"exact", "pending"},
	}
	if len(got) != len(want) || got[acousticKey] != want[acousticKey] || got[exactKey] != want[exactKey] {
		t.Fatalf("groups = %+v, want %+v", got, want)
	}
	for k := range got {
		if strings.Contains(k, missing) {
			t.Fatalf("a missing track was proposed: %s", k)
		}
	}

	// 2. A dismissed group is not proposed again, and the pending one is
	// refreshed in place rather than duplicated.
	if _, err := pool.Exec(ctx, "UPDATE duplicate_groups SET status = 'dismissed' WHERE member_key = $1", acousticKey); err != nil {
		t.Fatalf("dismiss: %v", err)
	}
	res, err = runDuplicateSweep(ctx, pool, logger, DefaultFingerprintSettings, duplicateCandidatePage)
	if err != nil {
		t.Fatalf("second sweep: %v", err)
	}
	if res.Proposed != 1 || res.Suppressed != 1 {
		t.Fatalf("second sweep = %+v, want 1 proposed, 1 suppressed", res)
	}
	got = groups()
	if len(got) != 2 || got[acousticKey].status != "dismissed" || got[exactKey].status != "pending" {
		t.Fatalf("after dismissal groups = %+v, want the dismissal kept and one pending group", got)
	}

	// 3. A proposal that no longer holds is retired; the dismissal survives it.
	if _, err := pool.Exec(ctx,
		"DELETE FROM track_fingerprints f USING tracks t WHERE f.track_id = t.id AND t.file_path LIKE '%www-02.mp3'"); err != nil {
		t.Fatalf("drop fingerprint: %v", err)
	}
	res, err = runDuplicateSweep(ctx, pool, logger, DefaultFingerprintSettings, duplicateCandidatePage)
	if err != nil {
		t.Fatalf("third sweep: %v", err)
	}
	if res.Retired != 1 {
		t.Fatalf("third sweep = %+v, want 1 retired", res)
	}
	got = groups()
	if len(got) != 1 || got[acousticKey].status != "dismissed" {
		t.Fatalf("after retiring groups = %+v, want only the dismissal", got)
	}

	// 4. The sweep record reflects the last run.
	last, err := q.GetLatestDuplicateSweep(ctx)
	if err != nil {
		t.Fatalf("latest sweep: %v", err)
	}
	if !last.FinishedAt.Valid || last.ErrorMessage != nil {
		t.Fatalf("latest sweep = %+v, want finished without error", last)
	}

	// 5. Prints taken at another length are never compared (#3913). Every print
	// here was taken at the default length, so a sweep at 60s has nothing to read,
	// rather than scoring 120s prints against each other as if they were 60s ones.
	atOtherLength := DefaultFingerprintSettings
	atOtherLength.ChromaprintLengthSec = 60
	res, err = runDuplicateSweep(ctx, pool, logger, atOtherLength, duplicateCandidatePage)
	if err != nil {
		t.Fatalf("sweep at another length: %v", err)
	}
	if res.Candidates != 0 || res.Groups != 0 {
		t.Fatalf("sweep at another length = %+v, want no candidates and no groups", res)
	}

	// 6. The sweep applies the threshold it is given. The recording's two copies
	// disagree on about 5% of their bits: grouped at the default, not at 1%.
	if _, err := pool.Exec(ctx, "DELETE FROM duplicate_groups"); err != nil {
		t.Fatalf("clear groups: %v", err)
	}
	strict := DefaultFingerprintSettings
	strict.AcousticMaxBitErrorRate = 0.01
	res, err = runDuplicateSweep(ctx, pool, logger, strict, duplicateCandidatePage)
	if err != nil {
		t.Fatalf("strict sweep: %v", err)
	}
	if res.Groups != 0 {
		t.Fatalf("sweep at a 1%% threshold = %+v, want the copies 5%% apart left ungrouped", res)
	}
	res, err = runDuplicateSweep(ctx, pool, logger, DefaultFingerprintSettings, duplicateCandidatePage)
	if err != nil {
		t.Fatalf("default sweep: %v", err)
	}
	if got := groups(); res.Groups != 1 || got[acousticKey] != (stored{"acoustic", "pending"}) {
		t.Fatalf("sweep at the default threshold = %+v, groups %+v; want the recording's copies proposed", res, got)
	}
}

func TestSweepIsDue(t *testing.T) {
	now := time.Date(2026, 9, 11, 12, 0, 0, 0, time.UTC)
	at := func(ago time.Duration) pgtype.Timestamptz {
		return pgtype.Timestamptz{Time: now.Add(-ago), Valid: true}
	}
	never := pgtype.Timestamptz{}
	hourly := DefaultFingerprintSettings
	daily := DefaultFingerprintSettings
	daily.SweepIntervalHours = 24
	savedAgo := func(ago time.Duration) FingerprintSettings {
		s := DefaultFingerprintSettings
		s.UpdatedAt = now.Add(-ago)
		return s
	}
	for _, tc := range []struct {
		name                   string
		latestPrint, lastSweep pgtype.Timestamptz
		cfg                    FingerprintSettings
		want                   bool
	}{
		{"nothing fingerprinted", never, never, hourly, false},
		{"never swept", at(time.Minute), never, hourly, true},
		{"new fingerprints since the last sweep", at(10 * time.Minute), at(2 * time.Hour), hourly, true},
		{"nothing new since the last sweep", at(3 * time.Hour), at(2 * time.Hour), hourly, false},
		// The sweep started a moment after the previous tick, so one tick later
		// it is a moment under an hour old. Without the slack this is false.
		{"one tick after an hourly sweep", at(time.Minute), at(time.Hour - 2*time.Second), hourly, true},
		{"new fingerprints inside the interval", at(time.Minute), at(3 * time.Hour), daily, false},
		{"new fingerprints past the interval", at(time.Minute), at(25 * time.Hour), daily, true},
		{"settings saved since the last sweep", at(3 * time.Hour), at(2 * time.Hour), savedAgo(time.Hour), true},
		{"settings saved before the last sweep", at(3 * time.Hour), at(2 * time.Hour), savedAgo(4 * time.Hour), false},
	} {
		if got := sweepIsDue(tc.latestPrint, tc.lastSweep, tc.cfg, now); got != tc.want {
			t.Errorf("%s: sweepIsDue = %v, want %v", tc.name, got, tc.want)
		}
	}
}