// Package constants provides global constants used across the application.
package constants

import (
	"fmt"
	"time"
)

// ==============================================================================
// HTTP CONTENT TYPES
// ==============================================================================

const (
	ContentTypeJSON         = "application/json"
	ContentTypeHTML         = "text/html; charset=utf-8"
	ContentTypeHTMLFragment = "text/html" // For HTMX fragments
	ContentTypePlainText    = "text/plain; charset=utf-8"
	ContentTypePlainSimple  = "text/plain" // For Accept header matching
	ContentTypePDF          = "application/pdf"
	ContentTypeFormURLEnc   = "application/x-www-form-urlencoded"
)

// ==============================================================================
// HTTP HEADERS
// ==============================================================================

const (
	HeaderContentType        = "Content-Type"
	HeaderContentDisposition = "Content-Disposition"
	HeaderContentLength      = "Content-Length"
	HeaderCacheControl       = "Cache-Control"
	HeaderXContentTypeOpts   = "X-Content-Type-Options"

	// HTMX headers
	HeaderHXRequest = "HX-Request"
	HeaderHXTrigger = "HX-Trigger"
)

// ==============================================================================
// CACHE CONTROL VALUES
// ==============================================================================

const (
	// CachePublic1Hour is for relatively static content (1 hour)
	CachePublic1Hour = "public, max-age=3600"

	// CachePublic1Day is for static files in production (1 day)
	CachePublic1Day = "public, max-age=86400"

	// CachePublic5Min is for dynamic content that can be cached briefly
	CachePublic5Min = "public, max-age=300, must-revalidate"

	// CacheNoStore prevents caching entirely
	CacheNoStore = "no-cache, no-store, must-revalidate"

	// CacheStatic is for truly static assets (1 year)
	CacheStatic = "public, max-age=31536000, immutable"
)

// Cache durations in seconds
const (
	CacheDuration1Hour  = 3600
	CacheDuration5Min   = 300
	CacheDuration1Year  = 31536000
	CacheDuration1Day   = 86400
	CacheDuration1Week  = 604800
	CacheDuration1Month = 2592000
)

// ==============================================================================
// LANGUAGE CODES
// ==============================================================================

const (
	LangEnglish = "en"
	LangSpanish = "es"
	LangDefault = LangEnglish
)

// SupportedLanguages is the set of valid language codes
var SupportedLanguages = map[string]bool{
	LangEnglish: true,
	LangSpanish: true,
}

// AllLangs returns all supported language codes
func AllLangs() []string {
	return []string{LangEnglish, LangSpanish}
}

// IsValidLang checks if a language code is supported
func IsValidLang(lang string) bool {
	return SupportedLanguages[lang]
}

// ValidateLang returns an error if the language code is unsupported.
// It provides helpful error messages showing all supported languages.
func ValidateLang(lang string) error {
	if !IsValidLang(lang) {
		return fmt.Errorf("unsupported language: %s (supported: %v)", lang, AllLangs())
	}
	return nil
}

// ==============================================================================
// CV PREFERENCES
// ==============================================================================

const (
	CVLengthShort  = "short"
	CVLengthLong   = "long"
	CVIconsShow    = "show"
	CVIconsHide    = "hide"
	CVThemeDefault = "default"
	CVThemeClean   = "clean"
)

// ==============================================================================
// COOKIE SETTINGS
// ==============================================================================

const (
	CookieMaxAge = 365 * 24 * 60 * 60 // 1 year in seconds
	CookiePath   = "/"
)

// ==============================================================================
// RATE LIMITING
// ==============================================================================

const (
	RateLimitPDFRequests     = 3
	RateLimitPDFWindow       = 1 * time.Minute
	RateLimitGeneralRequests = 100
	RateLimitGeneralWindow   = 1 * time.Minute
	RateLimitContactRequests = 5
	RateLimitContactWindow   = 1 * time.Hour
)

// ==============================================================================
// TIMEOUTS
// ==============================================================================

const (
	TimeoutPDFGeneration    = 30 * time.Second
	TimeoutHTTPRequest      = 10 * time.Second
	TimeoutIdleConnection   = 120 * time.Second
	TimeoutGracefulShutdown = 30 * time.Second
	FormMinSubmitTime       = 2 * time.Second // Min time form must be displayed (bot protection)
)

// ==============================================================================
// DIRECTORIES
// ==============================================================================

const (
	DirData      = "data"
	DirTemplates = "templates"
	DirPartials  = "templates/partials"
	DirStatic    = "static"
)

// ==============================================================================
// PDF DIMENSIONS
// ==============================================================================

const (
	A4WidthInches  = 8.27
	A4HeightInches = 11.69
)

// ==============================================================================
// CSRF PROTECTION
// ==============================================================================

const (
	CSRFTokenLength   = 32
	CSRFTokenTTL      = 24 * time.Hour
	CSRFCookieName    = "csrf_token"
	CSRFFormField     = "csrf_token"
	CSRFCleanupPeriod = 1 * time.Hour
)

// ==============================================================================
// CLEANUP INTERVALS
// ==============================================================================

const (
	RateLimitCleanupPeriod        = 10 * time.Minute // For contact rate limiter
	RateLimitGeneralCleanupPeriod = 1 * time.Minute  // For general rate limiter
)

// ==============================================================================
// SECURITY
// ==============================================================================

const (
	// HSTS max-age (1 year)
	HSTSMaxAge = "max-age=31536000; includeSubDomains; preload"

	// Content type options
	NoSniff = "nosniff"

	// Frame options
	FrameOptionsSameOrigin = "SAMEORIGIN"

	// XSS Protection
	XSSProtection = "1; mode=block"

	// Referrer Policy
	ReferrerPolicy = "strict-origin-when-cross-origin"
)

// ==============================================================================
// SECURITY HEADERS
// ==============================================================================

const (
	HeaderXFrameOptions     = "X-Frame-Options"
	HeaderXXSSProtection    = "X-XSS-Protection"
	HeaderReferrerPolicy    = "Referrer-Policy"
	HeaderPermissionsPolicy = "Permissions-Policy"
	HeaderCSP               = "Content-Security-Policy"
	HeaderHSTS              = "Strict-Transport-Security"
	HeaderRetryAfter        = "Retry-After"
	HeaderXForwardedFor     = "X-Forwarded-For"
	HeaderXRealIP           = "X-Real-IP"
	HeaderXCSRFToken        = "X-CSRF-Token"
)

// ==============================================================================
// REQUEST HEADERS
// ==============================================================================

const (
	HeaderUserAgent      = "User-Agent"
	HeaderAccept         = "Accept"
	HeaderOrigin         = "Origin"
	HeaderReferer        = "Referer"
	HeaderXRequestedWith = "X-Requested-With"
	HeaderXBrowserReq    = "X-Browser-Request"
)

// Header values
const (
	HeaderValueXMLHTTPRequest = "XMLHttpRequest"
)

// ==============================================================================
// ENVIRONMENT
// ==============================================================================

const (
	EnvProduction  = "production"
	EnvDevelopment = "development"

	EnvVarGOEnv = "GO_ENV"
	EnvVarPort  = "PORT"

	DefaultPort = "1999"
)

// ==============================================================================
// COOKIE NAMES
// ==============================================================================

const (
	CookieCVLength   = "cv-length"
	CookieCVIcons    = "cv-icons"
	CookieCVLanguage = "cv-language"
	CookieCVTheme    = "cv-theme"
	CookieColorTheme = "color-theme"
)

// ==============================================================================
// COLOR THEMES
// ==============================================================================

const (
	ColorThemeLight = "light"
	ColorThemeDark  = "dark"
)

// ==============================================================================
// ROUTES
// ==============================================================================

const (
	RouteHome       = "/"
	RouteHealth     = "/health"
	RouteExportPDF  = "/export/pdf"
	RouteAPIContact = "/api/contact"
	RouteAPICmdK    = "/api/cmd-k"
)