package playback

import (
	"errors"
	"testing"
)

func navigationPlaylist(loop bool) Playlist {
	return Playlist{
		Entries: []PlaylistEntry{
			{Name: "first", Video: PlaylistFeed{Domain: "domain", UUID: "video-1"}},
			{Name: "second", Audio: PlaylistFeed{Domain: "domain", UUID: "audio-2"}},
			{Name: "third", Video: PlaylistFeed{Domain: "domain", UUID: "video-3"}},
		},
		Loop: loop,
	}
}

func TestApplyPlaylistCommandSelect(t *testing.T) {
	current := PlaylistState{CurrentIndex: 1, HasSelection: true}

	got, err := ApplyPlaylistCommand(
		navigationPlaylist(false),
		current,
		PlaylistCommand{Kind: PlaylistSelect, Index: 2},
	)
	if err != nil {
		t.Fatalf("ApplyPlaylistCommand() error = %v", err)
	}
	want := PlaylistState{CurrentIndex: 2, HasSelection: true}
	if got != want {
		t.Fatalf("ApplyPlaylistCommand() = %#v, want %#v", got, want)
	}
}

func TestApplyPlaylistCommandWithoutSelection(t *testing.T) {
	tests := []struct {
		name    string
		loop    bool
		command PlaylistCommandKind
		want    int
	}{
		{name: "next", command: PlaylistNext, want: 0},
		{name: "previous without loop", command: PlaylistPrevious, want: 0},
		{name: "previous with loop", loop: true, command: PlaylistPrevious, want: 2},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			got, err := ApplyPlaylistCommand(
				navigationPlaylist(test.loop),
				PlaylistState{},
				PlaylistCommand{Kind: test.command},
			)
			if err != nil {
				t.Fatalf("ApplyPlaylistCommand() error = %v", err)
			}
			want := PlaylistState{CurrentIndex: test.want, HasSelection: true}
			if got != want {
				t.Fatalf("ApplyPlaylistCommand() = %#v, want %#v", got, want)
			}
		})
	}
}

func TestApplyPlaylistCommandNavigation(t *testing.T) {
	tests := []struct {
		name    string
		loop    bool
		current int
		command PlaylistCommandKind
		want    int
	}{
		{name: "next", current: 1, command: PlaylistNext, want: 2},
		{name: "previous", current: 1, command: PlaylistPrevious, want: 0},
		{name: "next stops at end", current: 2, command: PlaylistNext, want: 2},
		{name: "previous stops at beginning", current: 0, command: PlaylistPrevious, want: 0},
		{name: "next wraps", loop: true, current: 2, command: PlaylistNext, want: 0},
		{name: "previous wraps", loop: true, current: 0, command: PlaylistPrevious, want: 2},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			current := PlaylistState{CurrentIndex: test.current, HasSelection: true}
			got, err := ApplyPlaylistCommand(
				navigationPlaylist(test.loop),
				current,
				PlaylistCommand{Kind: test.command},
			)
			if err != nil {
				t.Fatalf("ApplyPlaylistCommand() error = %v", err)
			}
			want := PlaylistState{CurrentIndex: test.want, HasSelection: true}
			if got != want {
				t.Fatalf("ApplyPlaylistCommand() = %#v, want %#v", got, want)
			}
		})
	}
}

func TestApplyPlaylistCommandErrorsLeaveStateUnchanged(t *testing.T) {
	current := PlaylistState{CurrentIndex: 1, HasSelection: true}
	tests := []struct {
		name     string
		playlist Playlist
		command  PlaylistCommand
		wantErr  error
	}{
		{
			name:     "empty playlist",
			playlist: Playlist{},
			command:  PlaylistCommand{Kind: PlaylistNext},
			wantErr:  ErrPlaylistEmpty,
		},
		{
			name:     "negative selection",
			playlist: navigationPlaylist(false),
			command:  PlaylistCommand{Kind: PlaylistSelect, Index: -1},
			wantErr:  ErrPlaylistIndexOutOfRange,
		},
		{
			name:     "selection past end",
			playlist: navigationPlaylist(false),
			command:  PlaylistCommand{Kind: PlaylistSelect, Index: 3},
			wantErr:  ErrPlaylistIndexOutOfRange,
		},
		{
			name:     "stale current index",
			playlist: navigationPlaylist(false),
			command:  PlaylistCommand{Kind: PlaylistNext},
			wantErr:  ErrPlaylistIndexOutOfRange,
		},
		{
			name:     "unknown command",
			playlist: navigationPlaylist(false),
			command:  PlaylistCommand{},
			wantErr:  ErrUnknownPlaylistCommand,
		},
		{
			name: "invalid playlist",
			playlist: Playlist{Entries: []PlaylistEntry{
				{},
			}},
			command: PlaylistCommand{Kind: PlaylistNext},
			wantErr: ErrPlaylistEntryEmpty,
		},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			state := current
			if test.name == "stale current index" {
				state.CurrentIndex = 4
			}
			got, err := ApplyPlaylistCommand(test.playlist, state, test.command)
			if !errors.Is(err, test.wantErr) {
				t.Fatalf("ApplyPlaylistCommand() error = %v, want %v", err, test.wantErr)
			}
			if got != state {
				t.Fatalf("ApplyPlaylistCommand() = %#v, want unchanged %#v", got, state)
			}
		})
	}
}

func TestPlaylistStateEntry(t *testing.T) {
	playlist := navigationPlaylist(false)
	tests := []struct {
		name  string
		state PlaylistState
		want  string
		ok    bool
	}{
		{name: "no selection", state: PlaylistState{}},
		{name: "selected", state: PlaylistState{CurrentIndex: 1, HasSelection: true}, want: "second", ok: true},
		{name: "negative stale index", state: PlaylistState{CurrentIndex: -1, HasSelection: true}},
		{name: "stale index", state: PlaylistState{CurrentIndex: 3, HasSelection: true}},
	}

	for _, test := range tests {
		t.Run(test.name, func(t *testing.T) {
			entry, ok := test.state.Entry(playlist)
			if ok != test.ok {
				t.Fatalf("Entry() ok = %v, want %v", ok, test.ok)
			}
			if entry.Name != test.want {
				t.Fatalf("Entry() name = %q, want %q", entry.Name, test.want)
			}
		})
	}
}