package database

import (
	"context"
	"database/sql"
	"embed"
	"errors"
	"fmt"
	"log/slog"

	"queryorchestration/internal/serviceconfig/database"

	"github.com/golang-migrate/migrate/v4"
	_ "github.com/golang-migrate/migrate/v4/database/postgres"
	_ "github.com/golang-migrate/migrate/v4/source/file"
	"github.com/golang-migrate/migrate/v4/source/iofs"
	_ "github.com/lib/pq"
)

func createDB(ctx context.Context, cfg database.ConfigProvider) error {
	slog.Debug("creating connection to admin database", "uri", cfg.GetDBAdminDBURI())

	db, err := sql.Open(cfg.GetDBDriver(), cfg.GetDBAdminDBURI())
	if err != nil {
		return fmt.Errorf("error opening admin database: %w", err)
	}

	slog.Debug("pinging admin database", "uri", cfg.GetDBAdminDBURI())

	err = db.PingContext(ctx)
	if err != nil {
		return fmt.Errorf("error pinging admin database: %w", err)
	}

	slog.Debug("creating admin database", "uri", cfg.GetDBAdminDBURI())

	_, err = db.Exec(fmt.Sprintf("CREATE DATABASE %s", cfg.GetDBName()))
	if err != nil {
		slog.Info("database not created", "name", cfg.GetDBName(), "error", err.Error())
	} else {
		slog.Info("database created", "name", cfg.GetDBName())
	}

	slog.Debug("creating connection to database", "uri", cfg.GetDBAdminDBURI())

	db, err = sql.Open(cfg.GetDBDriver(), cfg.GetDBURI())
	if err != nil {
		return fmt.Errorf("error opening database: %w", err)
	}

	slog.Debug("pinging database", "uri", cfg.GetDBAdminDBURI())

	err = db.PingContext(ctx)
	if err != nil {
		return fmt.Errorf("error pinging database: %w", err)
	}

	return nil
}

//go:embed migrations/*.up.sql
var migrations embed.FS

func RunMigrations(ctx context.Context, cfg database.ConfigProvider) error {
	err := createDB(ctx, cfg)
	if err != nil {
		return err
	}

	source, err := iofs.New(migrations, "migrations")
	if err != nil {
		return err
	}

	m, err := migrate.NewWithSourceInstance("iofs", source, cfg.GetDBURI())
	if err != nil {
		return fmt.Errorf("failed to create migrate instance: %w", err)
	}

	err = m.Up()
	if errors.Is(err, migrate.ErrNoChange) {
		slog.Info("No migration changes required")
	} else if err != nil {
		return fmt.Errorf("failed to apply migrations: %w", err)
	} else {
		slog.Info("Migrations applied successfully!")
	}

	return nil
}