package main

import (
	"context"
	"database/sql"
	"fmt"
	"sync"
	"time"

	"git.ksdemosapps.com/kylesoda/go-migrate/internal/app/config"
	"github.com/jackc/pgx/v5/pgxpool"
	_ "github.com/microsoft/go-mssqldb"
	log "github.com/sirupsen/logrus"
)

func connectToSqlServer() (*sql.DB, error) {
	db, err := sql.Open("sqlserver", config.App.SourceDbUrl)
	if err != nil {
		return nil, fmt.Errorf("Unable to connect to sqlserver: %w", err)
	}

	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
	defer cancel()

	if err := db.PingContext(ctx); err != nil {
		return nil, fmt.Errorf("Unable to ping sqlserver: %w", err)
	}

	return db, nil
}

func connectToPostgres() (*pgxpool.Pool, error) {
	ctx, cancel := context.WithTimeout(context.Background(), 20*time.Second)
	defer cancel()

	pool, err := pgxpool.New(ctx, config.App.TargetDbUrl)
	if err != nil {
		return nil, fmt.Errorf("Unable to connect to postgres: %w", err)
	}

	if err := pool.Ping(ctx); err != nil {
		pool.Close()
		return nil, fmt.Errorf("Unable to ping postgres: %w", err)
	}

	return pool, nil
}

func connectToDatabases(sourceDb *sql.DB, targetDb *pgxpool.Pool) error {
	var sourceDbErr, targetDbErr error
	var wg sync.WaitGroup

	wg.Go(func() {
		sourceDb, sourceDbErr = connectToSqlServer()
		if sourceDbErr != nil {
			log.Error("Unable to connect to source db: ", sourceDbErr)
		}
	})

	wg.Go(func() {
		targetDb, targetDbErr = connectToPostgres()
		if targetDbErr != nil {
			log.Error("Unable to connect to target db: ", targetDbErr)
		}
	})

	wg.Wait()

	if sourceDbErr != nil || targetDbErr != nil {
		return fmt.Errorf("Unable to connect to databases: %w (source), %w (target)", sourceDbErr, targetDbErr)
	}

	return nil
}