package engine

import (
	"context"
	"time"

	"github.com/deluan/navidrome/model"
	"github.com/deluan/navidrome/model/request"
	"github.com/deluan/navidrome/utils"
)

type Playlists interface {
	GetAll(ctx context.Context) (model.Playlists, error)
	Get(ctx context.Context, id string) (*PlaylistInfo, error)
	Create(ctx context.Context, playlistId, name string, ids []string) error
	Delete(ctx context.Context, playlistId string) error
	Update(ctx context.Context, playlistId string, name *string, idsToAdd []string, idxToRemove []int) error
}

func NewPlaylists(ds model.DataStore) Playlists {
	return &playlists{ds}
}

type playlists struct {
	ds model.DataStore
}

func (p *playlists) Create(ctx context.Context, playlistId, name string, ids []string) error {
	return p.ds.WithTx(func(tx model.DataStore) error {
		owner := p.getUser(ctx)
		var pls *model.Playlist
		var err error

		// If playlistID is present, override tracks
		if playlistId != "" {
			pls, err = tx.Playlist(ctx).Get(playlistId)
			if err != nil {
				return err
			}
			if owner != pls.Owner {
				return model.ErrNotAuthorized
			}
			pls.Tracks = nil
		} else {
			pls = &model.Playlist{
				Name:  name,
				Owner: owner,
			}
		}
		for _, id := range ids {
			pls.Tracks = append(pls.Tracks, model.MediaFile{ID: id})
		}

		return tx.Playlist(ctx).Put(pls)
	})
}

func (p *playlists) getUser(ctx context.Context) string {
	user, ok := request.UserFrom(ctx)
	if ok {
		return user.UserName
	}
	return ""
}

func (p *playlists) Delete(ctx context.Context, playlistId string) error {
	return p.ds.WithTx(func(tx model.DataStore) error {
		pls, err := tx.Playlist(ctx).Get(playlistId)
		if err != nil {
			return err
		}

		owner := p.getUser(ctx)
		if owner != pls.Owner {
			return model.ErrNotAuthorized
		}
		return tx.Playlist(ctx).Delete(playlistId)
	})
}

func (p *playlists) Update(ctx context.Context, playlistId string, name *string, idsToAdd []string, idxToRemove []int) error {
	return p.ds.WithTx(func(tx model.DataStore) error {
		pls, err := tx.Playlist(ctx).Get(playlistId)
		if err != nil {
			return err
		}

		owner := p.getUser(ctx)
		if owner != pls.Owner {
			return model.ErrNotAuthorized
		}

		if name != nil {
			pls.Name = *name
		}
		newTracks := model.MediaFiles{}
		for i, t := range pls.Tracks {
			if utils.IntInSlice(i, idxToRemove) {
				continue
			}
			newTracks = append(newTracks, t)
		}

		for _, id := range idsToAdd {
			newTracks = append(newTracks, model.MediaFile{ID: id})
		}
		pls.Tracks = newTracks

		return tx.Playlist(ctx).Put(pls)
	})
}

func (p *playlists) GetAll(ctx context.Context) (model.Playlists, error) {
	return p.ds.Playlist(ctx).GetAll()
}

type PlaylistInfo struct {
	Id        string
	Name      string
	Entries   Entries
	SongCount int
	Duration  int
	Public    bool
	Owner     string
	Comment   string
	Created   time.Time
	Changed   time.Time
}

func (p *playlists) Get(ctx context.Context, id string) (*PlaylistInfo, error) {
	pl, err := p.ds.Playlist(ctx).Get(id)
	if err != nil {
		return nil, err
	}

	// TODO Use model.Playlist when got rid of Entries
	plsInfo := &PlaylistInfo{
		Id:        pl.ID,
		Name:      pl.Name,
		SongCount: pl.SongCount,
		Duration:  int(pl.Duration),
		Public:    pl.Public,
		Owner:     pl.Owner,
		Comment:   pl.Comment,
		Changed:   pl.UpdatedAt,
		Created:   pl.CreatedAt,
	}

	plsInfo.Entries = FromMediaFiles(pl.Tracks)
	return plsInfo, nil
}