package library

import (
	"context"
	"crypto/sha256"
	"encoding/hex"
	"errors"
	"os"

	"github.com/google/uuid"
	"github.com/jackc/pgx/v5"
)

type artistImageStore interface {
	ArtistWithoutImageForFile(context.Context, uuid.UUID) (uuid.UUID, error)
	SetArtistImageIfMissing(context.Context, uuid.UUID, string) error
}

type imageRenderer interface {
	StoreImage(context.Context, []byte) (string, error)
}

// ArtistImages applies approved portraits to the album artist, never guests.
type ArtistImages struct {
	store  artistImageStore
	images imageRenderer
}

func NewArtistImages(store *Store, covers *Covers) *ArtistImages {
	return &ArtistImages{store: store, images: covers}
}

func (a *ArtistImages) ApplyArtistImage(ctx context.Context, file uuid.UUID, data []byte) error {
	id, err := a.store.ArtistWithoutImageForFile(ctx, file)
	if errors.Is(err, ErrNotFound) {
		return nil
	}
	if err != nil {
		return err
	}
	key, err := a.images.StoreImage(ctx, data)
	if err != nil {
		return err
	}
	return a.store.SetArtistImageIfMissing(ctx, id, key)
}

func (c *Covers) StoreImage(ctx context.Context, data []byte) (string, error) {
	if err := os.MkdirAll(c.Dir, 0o755); err != nil {
		return "", err
	}
	sum := sha256.Sum256(data)
	key := hex.EncodeToString(sum[:8])
	_, err := c.render(ctx, data, key)
	return key, err
}

func (st *Store) ArtistWithoutImageForFile(ctx context.Context, file uuid.UUID) (uuid.UUID, error) {
	var id uuid.UUID
	err := st.pool.QueryRow(ctx, `SELECT a.id FROM media_files f JOIN tracks t ON t.id=f.track_id
		JOIN albums al ON al.id=t.album_id JOIN artists a ON a.id=al.album_artist_id
		WHERE f.id=$1 AND a.image_path IS NULL AND a.genius_image_url IS NULL`, file).Scan(&id)
	if errors.Is(err, pgx.ErrNoRows) {
		return id, ErrNotFound
	}
	return id, err
}

func (st *Store) SetArtistImageIfMissing(ctx context.Context, id uuid.UUID, key string) error {
	// Another import or Genius may have supplied a portrait during rendering.
	_, err := st.pool.Exec(ctx, `UPDATE artists SET image_path=$2 WHERE id=$1
		AND image_path IS NULL AND genius_image_url IS NULL`, id, key)
	return err
}