package config

import (
	"errors"
	"fmt"
	"os"
	"strconv"
)

type Config struct {
	HTTPAddr       string
	DatabaseURL    string
	RedisAddr      string
	RedisPassword  string
	ImportPath     string
	DemoUsername   string
	DemoPassword   string
	SessionSecret  string
	CursorSecret   string
	FrontendOrigin string
	CookieSecure   bool
}

func Load() (Config, error) {
	cfg := Config{
		HTTPAddr:       value("HTTP_ADDR", "127.0.0.1:8080"),
		DatabaseURL:    os.Getenv("DATABASE_URL"),
		RedisAddr:      value("REDIS_ADDR", "localhost:6379"),
		RedisPassword:  os.Getenv("REDIS_PASSWORD"),
		ImportPath:     value("IMPORT_PATH", "data/incoming/challenge_data.csv.gz"),
		DemoUsername:   value("DEMO_USERNAME", "merchant-0001"),
		DemoPassword:   os.Getenv("DEMO_PASSWORD"),
		SessionSecret:  os.Getenv("SESSION_SECRET"),
		CursorSecret:   os.Getenv("CURSOR_SECRET"),
		FrontendOrigin: value("FRONTEND_ORIGIN", "http://localhost:5173"),
	}

	var err error
	cfg.CookieSecure, err = strconv.ParseBool(value("COOKIE_SECURE", "false"))
	if err != nil {
		return Config{}, fmt.Errorf("parsing cookie secure: %w", err)
	}
	if cfg.DatabaseURL == "" {
		return Config{}, errors.New("config: DATABASE_URL is required")
	}
	return cfg, nil
}

func (c Config) ValidateAPI() error {
	if len(c.SessionSecret) < 32 {
		return errors.New("config: SESSION_SECRET must contain at least 32 characters")
	}
	if len(c.CursorSecret) < 32 {
		return errors.New("config: CURSOR_SECRET must contain at least 32 characters")
	}
	if c.CursorSecret == c.SessionSecret {
		return errors.New("config: CURSOR_SECRET must differ from SESSION_SECRET")
	}
	return nil
}

func (c Config) ValidateSeed() error {
	if len(c.DemoPassword) < 12 {
		return errors.New("config: DEMO_PASSWORD must contain at least 12 characters")
	}
	return nil
}

func value(name, fallback string) string {
	if value := os.Getenv(name); value != "" {
		return value
	}
	return fallback
}