package migrations

import (
	"database/sql"
	"fmt"
)

func MigrateClosedAtConstraint(db *sql.DB) error {
	var count int
	err := db.QueryRow(`
		SELECT COUNT(*)
		FROM issues
		WHERE (CASE WHEN status = 'closed' THEN 1 ELSE 0 END) <>
		      (CASE WHEN closed_at IS NOT NULL THEN 1 ELSE 0 END)
	`).Scan(&count)
	if err != nil {
		return fmt.Errorf("failed to count inconsistent issues: %w", err)
	}

	if count == 0 {
		return nil
	}

	_, err = db.Exec(`
		UPDATE issues
		SET closed_at = NULL
		WHERE status != 'closed' AND closed_at IS NOT NULL
	`)
	if err != nil {
		return fmt.Errorf("failed to clear closed_at for non-closed issues: %w", err)
	}

	_, err = db.Exec(`
		UPDATE issues
		SET closed_at = COALESCE(updated_at, CURRENT_TIMESTAMP)
		WHERE status = 'closed' AND closed_at IS NULL
	`)
	if err != nil {
		return fmt.Errorf("failed to set closed_at for closed issues: %w", err)
	}

	return nil
}