package engine

import (
	"io"
	"log/slog"
	"os"
	"path/filepath"
	"testing"

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

func renameLibrary(t *testing.T, dryRun bool) *env {
	ev := setup(t, dryRun)
	ev.write(ev.master, "AC_DC/Back in Black/01 Hells Bells.flac", "hb")
	ev.write(ev.slave, "AC-DC/Back In Black/01 Hells Bells.flac", "hb")
	ev.write(ev.master, "Avenged Sevenfold/City of Evil/03 Bat Country.flac", "bc")
	ev.write(ev.slave, "Avenged Sevenfold/City Of Evil/03 Bat Country.flac", "bc")
	ev.scan()
	return ev
}

func TestRenameFoldersToMasterSpelling(t *testing.T) {
	ev := renameLibrary(t, false)
	plan, err := ev.e.PreviewRenames(ctx, ev.pair.ID)
	if err != nil {
		t.Fatal(err)
	}
	if len(plan) != 2 || !plan[0].Ready || !plan[1].Ready {
		t.Fatalf("want 2 ready renames, got %+v", plan)
	}
	if _, err := ev.e.StartRenames(ev.pair.ID, nil); err != nil {
		t.Fatal(err)
	}
	j := ev.wait()
	// The artist rename reveals "Back In Black" inside it: a second pass fixes it.
	if j.Results["renamed"] != 3 {
		t.Fatalf("want 3 renames over two passes, got %+v %v", j.Results, j.Skipped)
	}
	for _, rel := range []string{"AC_DC/Back in Black/01 Hells Bells.flac", "Avenged Sevenfold/City of Evil/03 Bat Country.flac"} {
		if ev.read(filepath.Join(ev.slave, rel)) == "" {
			t.Fatalf("%s missing after rename", rel)
		}
		// The job rescans, so the songs now match by path.
		if m := ev.match(rel); m.Status != store.StatusIdentical || m.Kind != store.KindPath {
			t.Fatalf("%s should match by path after the rename, got %s/%s", rel, m.Status, m.Kind)
		}
	}
	p, _ := ev.st.Pair(ctx, ev.pair.ID)
	for _, w := range p.LastScanWarnings {
		if w.Code == store.WarnRenamedFolders {
			t.Fatalf("renamed-folders warning should be gone, got %+v", w)
		}
	}
	if ev.read(filepath.Join(ev.master, "AC_DC/Back in Black/01 Hells Bells.flac")) != "hb" {
		t.Fatal("the master library must not change")
	}

	// Undo the artist rename from History.
	ops, _, _ := ev.st.Ops(ctx, store.OpFilter{PairID: ev.pair.ID})
	var artist store.Operation
	for _, o := range ops {
		if o.Action == store.ActRename && o.RelSlave == "AC-DC" {
			artist = o
		}
	}
	if artist.ID == 0 || artist.RelNew != "AC_DC" {
		t.Fatalf("rename not recorded in history: %+v", ops)
	}
	if err := ev.e.Undo(ctx, artist.ID); err != nil {
		t.Fatal(err)
	}
	ev.wait() // undo starts a rescan
	if _, err := os.Stat(filepath.Join(ev.slave, "AC-DC/Back in Black/01 Hells Bells.flac")); err != nil {
		t.Fatalf("undo should rename the folder back: %v", err)
	}
}

func TestRenameConflictIsSkipped(t *testing.T) {
	ev := setup(t, false)
	ev.write(ev.master, "Band/Album Name/01 a.flac", "a")
	ev.write(ev.slave, "Band/Album name/01 a.flac", "a")
	ev.write(ev.slave, "Band/Album Name/02 b.flac", "b") // the master spelling already exists too
	ev.scan()
	plan, _ := ev.e.PreviewRenames(ctx, ev.pair.ID)
	if len(plan) != 1 || plan[0].Ready || plan[0].Reason == "" {
		t.Fatalf("want one conflicting rename, got %+v", plan)
	}
	if _, err := ev.e.StartRenames(ev.pair.ID, nil); err != nil {
		t.Fatal(err)
	}
	j := ev.wait()
	if j.Results["renamed"] != 0 || j.Results["skipped"] != 1 {
		t.Fatalf("conflict must be skipped, got %+v", j.Results)
	}
	if ev.read(filepath.Join(ev.slave, "Band/Album name/01 a.flac")) != "a" || ev.read(filepath.Join(ev.slave, "Band/Album Name/02 b.flac")) != "b" {
		t.Fatal("nothing may change on a conflict")
	}
}

func TestRenameOnlySelectedAndNeverArbitraryPaths(t *testing.T) {
	ev := renameLibrary(t, false)
	ev.write(ev.slave, "Unrelated/x.flac", "x")
	if _, err := ev.e.StartRenames(ev.pair.ID, []string{"Avenged Sevenfold/City Of Evil", "Unrelated"}); err != nil {
		t.Fatal(err)
	}
	j := ev.wait()
	if j.Results["renamed"] != 1 {
		t.Fatalf("only the selected, computed rename may run, got %+v", j.Results)
	}
	if _, err := os.Stat(filepath.Join(ev.slave, "AC-DC")); err != nil {
		t.Fatal("unselected folders must not be renamed")
	}
	if _, err := os.Stat(filepath.Join(ev.slave, "Unrelated/x.flac")); err != nil {
		t.Fatal("a folder that is not a computed rename must never be touched")
	}
}

func TestRenameDryRun(t *testing.T) {
	ev := renameLibrary(t, true)
	if _, err := ev.e.StartRenames(ev.pair.ID, nil); err != nil {
		t.Fatal(err)
	}
	j := ev.wait()
	if j.Results["planned"] != 2 {
		t.Fatalf("dry run should plan 2 renames, got %+v", j.Results)
	}
	if _, err := os.Stat(filepath.Join(ev.slave, "AC-DC")); err != nil {
		t.Fatal("dry run must not rename anything")
	}
}

func TestRecoverInterruptedCaseRename(t *testing.T) {
	root := t.TempDir()
	os.MkdirAll(filepath.Join(root, "Band", ".playlink-tmp-dir-abc123"), 0o755)
	os.WriteFile(filepath.Join(root, "Band", ".playlink-tmp-dir-abc123", "song.flac"), []byte("data"), 0o644)
	p := store.Pair{SlaveRoot: root}
	o := store.Operation{ID: 1, Action: store.ActRename, RelSlave: "Band/City Of Evil", RelNew: "Band/City of Evil"}
	recoverRename(p, o, slog.New(slog.NewTextHandler(io.Discard, nil)))
	if b, err := os.ReadFile(filepath.Join(root, "Band", "City of Evil", "song.flac")); err != nil || string(b) != "data" {
		t.Fatalf("interrupted rename should be completed, got %v", err)
	}
}

func TestRenameWarningCountsFixable(t *testing.T) {
	ev := setup(t, false)
	ev.write(ev.master, "Band/Album Name/01 a.flac", "a")
	ev.write(ev.slave, "Band/Album name/01 a.flac", "a")
	ev.write(ev.slave, "Band/Album Name/02 b.flac", "b") // conflict
	ev.write(ev.master, "Other/Record/01 c.flac", "c")
	ev.write(ev.slave, "Other/record/01 c.flac", "c") // renameable
	ev.scan()
	p, _ := ev.st.Pair(ctx, ev.pair.ID)
	for _, w := range p.LastScanWarnings {
		if w.Code == store.WarnRenamedFolders {
			if w.Total != 2 || w.Fixable != 1 {
				t.Fatalf("want 2 renamed folders, 1 fixable; got total=%d fixable=%d", w.Total, w.Fixable)
			}
			return
		}
	}
	t.Fatal("renamed-folders warning missing")
}