package albums

import (
	"context"
	"database/sql"
	"errors"
	"time"

	"shared-album/internal/models"
	"shared-album/internal/sqliteutil"
)

// SQLiteStore is the SQLite implementation of Repository.
type SQLiteStore struct {
	db *sql.DB
}

func NewSQLiteStore(db *sql.DB) *SQLiteStore { return &SQLiteStore{db: db} }

func (s *SQLiteStore) Create(ctx context.Context, a *models.Album) error {
	var createdAt, updatedAt string
	err := s.db.QueryRowContext(ctx,
		`INSERT INTO albums (id, owner_id, title, description, cover_photo_id)
		 VALUES ($1, $2, $3, $4, $5)
		 RETURNING created_at, updated_at`,
		a.ID, a.OwnerID, a.Title, a.Description, a.CoverPhotoID,
	).Scan(&createdAt, &updatedAt)
	if err != nil {
		return err
	}
	a.CreatedAt = sqliteutil.ParseTime(createdAt)
	a.UpdatedAt = sqliteutil.ParseTime(updatedAt)
	return nil
}

func (s *SQLiteStore) OwnerID(ctx context.Context, id string) (string, error) {
	var ownerID string
	err := s.db.QueryRowContext(ctx, `SELECT owner_id FROM albums WHERE id = $1`, id).Scan(&ownerID)
	if err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return "", ErrNotFound
		}
		return "", err
	}
	return ownerID, nil
}

const sqliteAlbumColumns = `a.id, a.owner_id, a.title, a.description, a.cover_photo_id,
	a.created_at, a.updated_at, COALESCE(co.storage_key, ''),
	(SELECT count(*) FROM photos WHERE album_id = a.id),
	(SELECT count(*) FROM album_members WHERE album_id = a.id)`

const sqliteAlbumJoins = `
	LEFT JOIN photo_objects cpo ON cpo.photo_id = a.cover_photo_id AND cpo.role = 'thumb'
	LEFT JOIN objects co ON co.id = cpo.object_id`

func scanSQLiteAlbum(scan func(...any) error) (*models.Album, error) {
	var a models.Album
	var cover sql.NullString
	var createdAt, updatedAt string
	if err := scan(&a.ID, &a.OwnerID, &a.Title, &a.Description, &cover, &createdAt, &updatedAt,
		&a.CoverThumbKey, &a.PhotosCount, &a.MembersCount); err != nil {
		return nil, err
	}
	if cover.Valid {
		a.CoverPhotoID = &cover.String
	}
	a.CreatedAt = sqliteutil.ParseTime(createdAt)
	a.UpdatedAt = sqliteutil.ParseTime(updatedAt)
	return &a, nil
}

func (s *SQLiteStore) GetByID(ctx context.Context, id string) (*models.Album, error) {
	row := s.db.QueryRowContext(ctx,
		`SELECT `+sqliteAlbumColumns+` FROM albums a`+sqliteAlbumJoins+` WHERE a.id = $1`, id)
	a, err := scanSQLiteAlbum(row.Scan)
	if err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return nil, ErrNotFound
		}
		return nil, err
	}
	return a, nil
}

func (s *SQLiteStore) ListForUser(ctx context.Context, userID string) ([]models.Album, error) {
	rows, err := s.db.QueryContext(ctx,
		`SELECT `+sqliteAlbumColumns+` FROM albums a
		 LEFT JOIN album_members m ON m.album_id = a.id AND m.user_id = $1`+sqliteAlbumJoins+`
		 WHERE a.owner_id = $1 OR m.user_id IS NOT NULL
		 ORDER BY a.created_at DESC`, userID)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	out := []models.Album{}
	for rows.Next() {
		a, err := scanSQLiteAlbum(rows.Scan)
		if err != nil {
			return nil, err
		}
		out = append(out, *a)
	}
	return out, rows.Err()
}

func (s *SQLiteStore) Update(ctx context.Context, a *models.Album) error {
	var updatedAt string
	err := s.db.QueryRowContext(ctx,
		`UPDATE albums
		 SET title = $2, description = $3, cover_photo_id = $4, updated_at = $5
		 WHERE id = $1
		 RETURNING updated_at`,
		a.ID, a.Title, a.Description, a.CoverPhotoID, sqliteutil.FormatTime(time.Now().UTC()),
	).Scan(&updatedAt)
	if err != nil {
		if errors.Is(err, sql.ErrNoRows) {
			return ErrNotFound
		}
		return err
	}
	a.UpdatedAt = sqliteutil.ParseTime(updatedAt)
	return nil
}

func (s *SQLiteStore) Delete(ctx context.Context, id string) error {
	res, err := s.db.ExecContext(ctx, `DELETE FROM albums WHERE id = $1`, id)
	if err != nil {
		return err
	}
	if n, _ := res.RowsAffected(); n == 0 {
		return ErrNotFound
	}
	return nil
}

func (s *SQLiteStore) TrashPhotosByAlbum(ctx context.Context, albumID string) error {
	_, err := s.db.ExecContext(ctx,
		`UPDATE photos SET deleted_at = $2 WHERE album_id = $1 AND deleted_at IS NULL`,
		albumID, sqliteutil.FormatTime(time.Now().UTC()))
	return err
}