package database

import (
	"context"
	"database/sql"
	"fmt"
	"log/slog"
	"time"

	"gorm.io/driver/postgres"
	"gorm.io/gorm"
)

type OpenOptions struct {
	MaxOpenConns    int
	MaxIdleConns    int
	ConnMaxIdleTime time.Duration
	ConnMaxLifetime time.Duration
}

func defaultOpenOptions() OpenOptions {
	return OpenOptions{MaxOpenConns: 20, MaxIdleConns: 5, ConnMaxIdleTime: 5 * time.Minute, ConnMaxLifetime: 30 * time.Minute}
}

func normalizeOpenOptions(options []OpenOptions) (OpenOptions, error) {
	if len(options) == 0 {
		return defaultOpenOptions(), nil
	}
	value := options[0]
	if value.MaxOpenConns < 1 || value.MaxIdleConns < 0 || value.MaxIdleConns > value.MaxOpenConns {
		return OpenOptions{}, fmt.Errorf("invalid database connection pool limits")
	}
	if value.ConnMaxIdleTime <= 0 || value.ConnMaxLifetime <= 0 {
		return OpenOptions{}, fmt.Errorf("database connection lifetimes must be positive")
	}
	return value, nil
}

func Open(ctx context.Context, dsn string, appLogger *slog.Logger, options ...OpenOptions) (*gorm.DB, error) {
	poolOptions, err := normalizeOpenOptions(options)
	if err != nil {
		return nil, err
	}
	db, err := gorm.Open(postgres.New(postgres.Config{DSN: dsn}), &gorm.Config{
		Logger:         newStructuredGORMLogger(appLogger),
		TranslateError: true,
	})
	if err != nil {
		return nil, fmt.Errorf("open postgres: %w", err)
	}

	sqlDB, err := db.DB()
	if err != nil {
		return nil, fmt.Errorf("get sql db: %w", err)
	}
	sqlDB.SetMaxOpenConns(poolOptions.MaxOpenConns)
	sqlDB.SetMaxIdleConns(poolOptions.MaxIdleConns)
	sqlDB.SetConnMaxIdleTime(poolOptions.ConnMaxIdleTime)
	sqlDB.SetConnMaxLifetime(poolOptions.ConnMaxLifetime)

	pingCtx, cancel := context.WithTimeout(ctx, 5*time.Second)
	defer cancel()
	if err := sqlDB.PingContext(pingCtx); err != nil {
		_ = sqlDB.Close()
		return nil, fmt.Errorf("ping postgres: %w", err)
	}
	appLogger.Info("database connected")
	return db, nil
}

func Close(db *gorm.DB) error {
	sqlDB, err := db.DB()
	if err != nil {
		return err
	}
	return sqlDB.Close()
}

func SQLDB(db *gorm.DB) (*sql.DB, error) {
	return db.DB()
}