package repositories

import (
	"context"
	"database/sql"
	"fmt"
	"strings"
	"thamanyah/cms/v2/internal/models"
)

type VideoRepository struct {
	SQLDB *sql.DB
}

var VideoRepo VideoRepository

// VideoExistsWithStorageKey reports whether a video has already been
// registered under a storage key. It is served by videos_storage_key_key, the
// index Postgres builds for the column's UNIQUE constraint.
func (svc VideoRepository) VideoExistsWithStorageKey(ctx context.Context, storageKey string) (bool, error) {
	var exists bool
	err := svc.SQLDB.QueryRowContext(ctx,
		`SELECT EXISTS (SELECT 1 FROM videos WHERE storage_key = $1)`, storageKey).Scan(&exists)
	if err != nil {
		return false, err
	}
	return exists, nil
}

func (svc VideoRepository) CreateVideo(ctx context.Context, v models.Video) (models.Video, error) {
	tx, err := svc.SQLDB.BeginTx(ctx, nil)
	if err != nil {
		return models.Video{}, err
	}
	defer tx.Rollback()

	row := tx.QueryRowContext(ctx, `
		INSERT INTO videos (title, description, tags, file_name, storage_key, mediaconvert_job_id, status, size_bytes)
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8)
		RETURNING id, created_at, updated_at
	`, v.Title, v.Description, v.Tags, v.FileName, v.StorageKey, v.MediaConvertJobID, string(v.Status), v.SizeBytes)

	if err := row.Scan(&v.ID, &v.CreatedAt, &v.UpdatedAt); err != nil {
		return models.Video{}, err
	}

	rows := make([]string, 0, len(v.CategoryIDs))
	for _, categoryID := range v.CategoryIDs {
		rows = append(rows, fmt.Sprintf("($1, %d)", categoryID))
	}

	if _, err := tx.ExecContext(ctx, `INSERT INTO video_categories (video_id, category_id) VALUES `+strings.Join(rows, ", "), v.ID); err != nil {
		return models.Video{}, fmt.Errorf("linking categories %v: %w", v.CategoryIDs, err)
	}

	if err := tx.Commit(); err != nil {
		return models.Video{}, err
	}

	return v, nil
}