package engine

import (
	"encoding/json"
	"errors"
	"path/filepath"
	"testing"

	"github.com/cdnutter/playlink/internal/probe"
	"github.com/cdnutter/playlink/internal/store"
)

// setVerdict simulates the quality comparison (tests run without ffprobe).
func setVerdict(t *testing.T, ev *env, rel, better string) {
	t.Helper()
	m := ev.match(rel)
	m.Verdict, _ = json.Marshal(probe.Verdict{Better: better})
	if err := ev.st.UpsertMatch(ctx, &m); err != nil {
		t.Fatal(err)
	}
}

// An album with every kind of song: the bulk plan must treat each correctly.
func bulkAlbum(t *testing.T, ev *env) (album string, ids []int64) {
	album = "Avenged Sevenfold/Nightmare"
	ev.write(ev.master, album+"/01 Nightmare.flac", "same")
	ev.write(ev.slave, album+"/01 Nightmare.flac", "same") // identical
	ev.write(ev.master, album+"/02 Welcome to the Family.flac", "flac")
	ev.write(ev.slave, album+"/02 Welcome to the Family.flac", "mp3!!") // different, master better
	ev.write(ev.master, album+"/Disc 2/03 Danger Line.mp3", "lossy")
	ev.write(ev.slave, album+"/Disc 2/03 Danger Line.mp3", "lossless") // different, slave better
	ev.write(ev.slave, album+"/04 Slave Only.mp3", "only")             // unmatched
	ev.write(ev.master, album+"/05 Ignored.flac", "a")
	ev.write(ev.slave, album+"/05 Ignored.flac", "b") // different, ignored
	ev.scan()
	setVerdict(t, ev, album+"/02 Welcome to the Family.flac", "master")
	setVerdict(t, ev, album+"/Disc 2/03 Danger Line.mp3", "slave")
	if err := ev.st.SetIgnored(ctx, ev.match(album+"/05 Ignored.flac").ID, true); err != nil {
		t.Fatal(err)
	}
	groups, err := ev.e.Groups(ctx, ev.pair.ID, store.MatchFilter{})
	if err != nil {
		t.Fatal(err)
	}
	if len(groups) != 1 || groups[0].Folder != album || groups[0].Songs != 5 {
		t.Fatalf("disc folders should fold into one album group, got %+v", groups)
	}
	g := groups[0]
	if g.Identical != 1 || g.Review != 2 || g.Upgrades != 1 || g.Downgrades != 1 || g.Other != 2 {
		t.Fatalf("group counts wrong: %+v", g)
	}
	return album, g.IDs
}

func TestBulkLinkAlbum(t *testing.T) {
	ev := setup(t, false)
	album, ids := bulkAlbum(t, ev)

	p, err := ev.e.PreviewBulk(ctx, ev.pair.ID, append(ids, ids[0]), BulkOptions{Action: BulkLink})
	if err != nil {
		t.Fatal(err)
	}
	if p.Selected != 5 || p.Albums != 1 || p.Process != 2 || p.Identical != 1 || p.Quarantined != 1 || p.Upgrades != 1 || p.BytesFreed != 4 {
		t.Fatalf("preview wrong: %+v", p)
	}
	if p.Skip["master copy is lower quality"] != 1 || p.Skip["no master copy"] != 1 || p.Skip["ignored"] != 1 {
		t.Fatalf("skip reasons wrong: %+v", p.Skip)
	}

	if _, err := ev.e.StartBulk(ev.pair.ID, ids, BulkOptions{Action: BulkLink}); err != nil {
		t.Fatal(err)
	}
	j := ev.wait()
	if j.Results["linked"] != 2 || j.Results["skipped"] != 3 {
		t.Fatalf("job results %+v %v", j.Results, j.Skipped)
	}
	for _, rel := range []string{"/01 Nightmare.flac", "/02 Welcome to the Family.flac"} {
		if !sameInode(t, filepath.Join(ev.master, album+rel), filepath.Join(ev.slave, album+rel)) {
			t.Fatalf("%s should be linked", rel)
		}
	}
	danger := album + "/Disc 2/03 Danger Line.mp3"
	if sameInode(t, filepath.Join(ev.master, danger), filepath.Join(ev.slave, danger)) {
		t.Fatal("the downgrade must be skipped without explicit permission")
	}

	// With explicit permission the downgrade is linked too.
	p, _ = ev.e.PreviewBulk(ctx, ev.pair.ID, ids, BulkOptions{Action: BulkLink, AllowDowngrade: true})
	if p.Process != 1 || p.Downgrades != 1 || len(p.Examples["downgrades"]) != 1 {
		t.Fatalf("preview with downgrades: %+v", p)
	}
	if _, err := ev.e.StartBulk(ev.pair.ID, ids, BulkOptions{Action: BulkLink, AllowDowngrade: true}); err != nil {
		t.Fatal(err)
	}
	ev.wait()
	if !sameInode(t, filepath.Join(ev.master, danger), filepath.Join(ev.slave, danger)) {
		t.Fatal("downgrade should be linked once allowed")
	}
	if ev.read(filepath.Join(ev.slave, album+"/05 Ignored.flac")) != "b" {
		t.Fatal("ignored songs must never be touched")
	}
}

func TestBulkPromoteAlbum(t *testing.T) {
	ev := setup(t, false)
	album, ids := bulkAlbum(t, ev)
	p, err := ev.e.PreviewBulk(ctx, ev.pair.ID, ids, BulkOptions{Action: BulkPromote})
	if err != nil {
		t.Fatal(err)
	}
	if p.Process != 1 || p.Skip["master copy is better"] != 1 || p.Skip["identical, so link instead"] != 1 || len(p.Examples["master_replaced"]) != 1 {
		t.Fatalf("promote preview: %+v", p)
	}
	if _, err := ev.e.StartBulk(ev.pair.ID, ids, BulkOptions{Action: BulkPromote}); err != nil {
		t.Fatal(err)
	}
	j := ev.wait()
	if j.Results["promoted"] != 1 {
		t.Fatalf("promote results %+v %v", j.Results, j.Skipped)
	}
	if ev.read(filepath.Join(ev.master, album+"/Disc 2/03 Danger Line.mp3")) != "lossless" {
		t.Fatal("the better slave copy should now be the master file")
	}
	if ev.read(filepath.Join(ev.master, album+"/02 Welcome to the Family.flac")) != "flac" {
		t.Fatal("a better master copy must not be replaced")
	}
}

func TestBulkIgnoreAndSafety(t *testing.T) {
	ev := setup(t, false)
	_, ids := bulkAlbum(t, ev)
	n, err := ev.e.ApplyIgnore(ctx, ev.pair.ID, ids, BulkOptions{Action: BulkIgnore})
	if err != nil || n != 4 {
		t.Fatalf("ignore changed %d (%v), want 4", n, err)
	}
	n, _ = ev.e.ApplyIgnore(ctx, ev.pair.ID, ids, BulkOptions{Action: BulkUnignore})
	if n != 5 {
		t.Fatalf("unignore changed %d, want 5", n)
	}

	// IDs from another pair are refused.
	other := store.Pair{Name: "other", MasterRoot: ev.master, SlaveRoot: ev.slave}
	if _, err := ev.e.NormalizePair(&other); err != nil {
		t.Fatal(err)
	}
	if err := ev.st.SavePair(ctx, &other); err != nil {
		t.Fatal(err)
	}
	p, _ := ev.e.PreviewBulk(ctx, other.ID, ids, BulkOptions{Action: BulkLink})
	if p.Process != 0 || p.Skip["belongs to another library pair"] != 5 {
		t.Fatalf("cross-pair ids must be skipped: %+v", p)
	}
	if _, err := ev.e.PreviewBulk(ctx, ev.pair.ID, nil, BulkOptions{Action: BulkLink}); !errors.Is(err, ErrInvalidBulk) {
		t.Fatalf("empty selection: %v", err)
	}
	if _, err := ev.e.StartBulk(ev.pair.ID, ids, BulkOptions{Action: "delete"}); !errors.Is(err, ErrInvalidBulk) {
		t.Fatalf("unknown action: %v", err)
	}
}

func TestAlbumFolder(t *testing.T) {
	for in, want := range map[string]string{
		"A/Album/01 x.flac":         "A/Album",
		"A/Album/Disc 2/01 x.flac":  "A/Album",
		"A/Album/CD1/Disc 1/x.flac": "A/Album",
		"x.flac":                    "",
		"Disc 1/x.flac":             "",
	} {
		if got := AlbumFolder(in); got != want {
			t.Errorf("AlbumFolder(%q) = %q, want %q", in, got, want)
		}
	}
}