package config

import (
	"bufio"
	"fmt"
	"net/url"
	"os"
	"strconv"
	"strings"
	"time"
)

type Config struct {
	AppHost           string
	AppPort           string
	DBHost            string
	DBPort            string
	DBDatabase        string
	DBUsername        string
	DBPassword        string
	BearerToken       string
	DBMaxOpenConns    int
	DBMaxIdleConns    int
	DBConnMaxLifetime time.Duration
}

func Load(path string) (Config, error) {
	if err := loadDotEnv(path); err != nil {
		return Config{}, err
	}

	cfg := Config{
		AppHost:           env("APP_HOST", "0.0.0.0"),
		AppPort:           env("APP_PORT", "8080"),
		DBHost:            env("DB_HOST", "127.0.0.1"),
		DBPort:            env("DB_PORT", "3306"),
		DBDatabase:        env("DB_DATABASE", ""),
		DBUsername:        env("DB_USERNAME", "root"),
		DBPassword:        env("DB_PASSWORD", ""),
		BearerToken:       env("CPONE_BEARER_TOKEN", ""),
		DBMaxOpenConns:    envInt("DB_MAX_OPEN_CONNS", 25),
		DBMaxIdleConns:    envInt("DB_MAX_IDLE_CONNS", 25),
		DBConnMaxLifetime: time.Duration(envInt("DB_CONN_MAX_LIFETIME_MINUTES", 5)) * time.Minute,
	}

	if cfg.DBDatabase == "" {
		return Config{}, fmt.Errorf("DB_DATABASE wajib diisi")
	}
	if cfg.BearerToken == "" {
		return Config{}, fmt.Errorf("CPONE_BEARER_TOKEN wajib diisi")
	}

	return cfg, nil
}

func (c Config) Addr() string {
	return c.AppHost + ":" + c.AppPort
}

func (c Config) MySQLDSN() string {
	values := url.Values{}
	values.Set("charset", "utf8mb4")
	values.Set("parseTime", "true")
	values.Set("loc", "Local")

	return fmt.Sprintf(
		"%s:%s@tcp(%s:%s)/%s?%s",
		c.DBUsername,
		c.DBPassword,
		c.DBHost,
		c.DBPort,
		c.DBDatabase,
		values.Encode(),
	)
}

func loadDotEnv(path string) error {
	file, err := os.Open(path)
	if err != nil {
		if os.IsNotExist(err) {
			return nil
		}
		return err
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)
	for scanner.Scan() {
		line := strings.TrimSpace(scanner.Text())
		if line == "" || strings.HasPrefix(line, "#") {
			continue
		}

		key, value, ok := strings.Cut(line, "=")
		if !ok {
			continue
		}

		key = strings.TrimSpace(key)
		value = strings.TrimSpace(value)
		value = strings.Trim(value, `"'`)

		if key != "" {
			_ = os.Setenv(key, value)
		}
	}

	return scanner.Err()
}

func env(key string, fallback string) string {
	value := os.Getenv(key)
	if value == "" {
		return fallback
	}
	return value
}

func envInt(key string, fallback int) int {
	value := os.Getenv(key)
	if value == "" {
		return fallback
	}

	parsed, err := strconv.Atoi(value)
	if err != nil {
		return fallback
	}

	return parsed
}