package app

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

	mig "github.com/golang-migrate/migrate/v4"
	_ "github.com/golang-migrate/migrate/v4/database/postgres"
	"github.com/golang-migrate/migrate/v4/source/iofs"
	"github.com/jackc/pgx/v5/pgxpool"
	_ "github.com/jackc/pgx/v5/stdlib"
)

func NewPGXPool(datasource string) *pgxpool.Pool {
	dbPool, err := pgxpool.New(context.Background(), datasource)
	if err != nil {
		slog.Error("error connecting to database", "error", err, "datasource", datasource)
		panic(err)
	}

	if err := dbPool.Ping(context.Background()); err != nil {
		slog.Error("error pinging database, maybe incorrect datasource", "error", err, "datasource", datasource)
		panic(err)
	}
	slog.Info("connected to database", "datasource", datasource)
	return dbPool
}

func Migrate(database embed.FS) {
	dbConn, err := sql.Open("pgx", os.Getenv("DATASOURCE"))
	if err != nil {
		slog.Error("error opening database connection", "error", err)
		return
	}
	defer dbConn.Close()

	d, err := iofs.New(database, "database/migrations")
	if err != nil {
		slog.Error("error creating migration source", "error", err)
		return
	}

	m, err := mig.NewWithSourceInstance("iofs", d, fmt.Sprintf("postgres://%s:%s@%s", os.Getenv("POSTGRES_USER"), os.Getenv("POSTGRES_PASSWORD"), os.Getenv("DSN")))
	if err != nil {
		slog.Error("error creating migration instance", "error", err)
		return
	}

	err = m.Up()
	if err != nil && !errors.Is(err, mig.ErrNoChange) {
		slog.Error("cannot migrate", "error", err)
		panic(err)
	}
	if errors.Is(err, mig.ErrNoChange) {
		slog.Info("migration has no changes")
		return
	}

	slog.Info("migration done")
}