// Package config loads runtime settings from the environment.
package config

import (
	"os"
	"strconv"
	"time"
)

type Config struct {
	// Storage: "postgres" (default) or "memory" (no infra, for dev/tests).
	Store       string
	DatabaseURL string

	RedisAddr      string
	RedisPassword  string
	RedisDB        int
	RedisKeyPrefix string

	// PublicURL is the externally reachable base (used to build OAuth callback
	// URLs). PostLoginRedirect is where users land after a successful login.
	PublicURL         string
	PostLoginRedirect string

	// FrontendDist is the directory of the built SPA served by the frontend cmd.
	FrontendDist string

	// ShortDomain is the display host for short links (e.g. snip.to).
	ShortDomain string

	SessionSecret string
	CookieSecure  bool

	// Identity providers (each optional; absent => that login button is hidden).
	GoogleClientID     string
	GoogleClientSecret string
	OIDCIssuer         string
	OIDCClientID       string
	OIDCClientSecret   string

	ClickFlushInterval time.Duration
}

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

func envBool(key string, def bool) bool {
	if v := os.Getenv(key); v != "" {
		b, err := strconv.ParseBool(v)
		if err == nil {
			return b
		}
	}
	return def
}

func envInt(key string, def int) int {
	if v := os.Getenv(key); v != "" {
		n, err := strconv.Atoi(v)
		if err == nil {
			return n
		}
	}
	return def
}

// Load reads configuration from the environment with sensible local defaults.
func Load() Config {
	flush := time.Duration(envInt("CLICK_FLUSH_SECONDS", 10)) * time.Second
	return Config{
		Store:              env("STORE", "postgres"),
		DatabaseURL:        env("DATABASE_URL", "postgres://snip:snip@localhost:5432/snip?sslmode=disable"),
		RedisAddr:          env("REDIS_ADDR", "localhost:6379"),
		RedisPassword:      env("REDIS_PASSWORD", ""),
		RedisDB:            envInt("REDIS_DB", 0),
		RedisKeyPrefix:     env("REDIS_KEY_PREFIX", ""),
		PublicURL:          env("PUBLIC_URL", "http://localhost:8080"),
		PostLoginRedirect:  env("POST_LOGIN_REDIRECT", "/dashboard"),
		FrontendDist:       env("FRONTEND_DIST", "./web"),
		ShortDomain:        env("SHORT_DOMAIN", "snip.to"),
		SessionSecret:      env("SESSION_SECRET", "dev-insecure-secret-change-me"),
		CookieSecure:       envBool("COOKIE_SECURE", false),
		GoogleClientID:     env("GOOGLE_CLIENT_ID", ""),
		GoogleClientSecret: env("GOOGLE_CLIENT_SECRET", ""),
		OIDCIssuer:         env("OIDC_ISSUER", ""),
		OIDCClientID:       env("OIDC_CLIENT_ID", ""),
		OIDCClientSecret:   env("OIDC_CLIENT_SECRET", ""),
		ClickFlushInterval: flush,
	}
}