package postgresadmin

import (
	"context"
	"errors"
	"fmt"
	"time"

	"github.com/jackc/pgx/v5/pgxpool"

	"proxy-pool/internal/domain/adminstate"
)

// ApplyMigrations runs every embedded idempotent migration on one physical connection.
func ApplyMigrations(ctx context.Context, pool *pgxpool.Pool) error {
	if err := contextError(ctx); err != nil {
		return err
	}
	if isNil(pool) {
		return adminstate.ErrInvalidCommand
	}
	connection, err := pool.Acquire(ctx)
	if err != nil {
		return migrationError(ctx, err)
	}
	defer connection.Release()

	for _, migration := range Migrations() {
		if _, err := connection.Exec(ctx, migration.SQL); err != nil {
			rollbackContext, cancel := context.WithTimeout(context.Background(), 5*time.Second)
			defer cancel()
			_, _ = connection.Exec(rollbackContext, "ROLLBACK")
			return migrationError(ctx, err)
		}
	}
	return nil
}

func migrationError(ctx context.Context, err error) error {
	if ctx != nil && ctx.Err() != nil {
		return ctx.Err()
	}
	if errors.Is(err, context.Canceled) || errors.Is(err, context.DeadlineExceeded) {
		return err
	}
	return fmt.Errorf("postgresadmin: apply migrations: %w", adminstate.ErrUnavailable)
}