package config

import (
	"os"
	"strconv"

	"gopkg.in/yaml.v3"
)

type Config struct {
	HTTP struct {
		Addr string `yaml:"addr"`
	} `yaml:"http"`
	Database struct {
		DSN          string `yaml:"dsn"`
		MaxOpenConns int    `yaml:"max_open_conns"`
		MaxIdleConns int    `yaml:"max_idle_conns"`
	} `yaml:"database"`
	Redis struct {
		Addr       string `yaml:"addr"`
		TTLSeconds int    `yaml:"ttl_seconds"`
	} `yaml:"redis"`
	JWT struct {
		Secret     string `yaml:"secret"`
		TTLMinutes int    `yaml:"ttl_minutes"`
	} `yaml:"jwt"`
	RateLimit struct {
		RequestsPerMinute int `yaml:"requests_per_minute"`
	} `yaml:"rate_limit"`
	Email struct {
		Endpoint string `yaml:"endpoint"`
	} `yaml:"email"`
}

func Load() (Config, error) {
	path := getenv("APP_CONFIG", "config.yaml")
	data, err := os.ReadFile(path)
	if err != nil {
		return Config{}, err
	}
	var cfg Config
	if err := yaml.Unmarshal(data, &cfg); err != nil {
		return Config{}, err
	}
	override(&cfg)
	return cfg, nil
}

func override(cfg *Config) {
	if v := os.Getenv("HTTP_ADDR"); v != "" {
		cfg.HTTP.Addr = v
	}
	if v := os.Getenv("DB_DSN"); v != "" {
		cfg.Database.DSN = v
	}
	if v := os.Getenv("REDIS_ADDR"); v != "" {
		cfg.Redis.Addr = v
	}
	if v := os.Getenv("JWT_SECRET"); v != "" {
		cfg.JWT.Secret = v
	}
	if v := os.Getenv("RATE_LIMIT_RPM"); v != "" {
		if n, err := strconv.Atoi(v); err == nil {
			cfg.RateLimit.RequestsPerMinute = n
		}
	}
}

func getenv(key, fallback string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return fallback
}