// Package httputil provides simple HTTP request/response utilities.
package httputil

import (
	"net/http"

	c "github.com/juanatsap/cv-site/internal/constants"
)

// Lang extracts and validates the language from query params.
// Returns the language or default if invalid/missing.
func Lang(r *http.Request) string {
	lang := r.URL.Query().Get("lang")
	if lang == "" || !c.SupportedLanguages[lang] {
		return c.LangDefault
	}
	return lang
}

// LangOrError extracts and validates language, returns error if invalid.
// Returns (lang, true) if valid, ("", false) if invalid.
func LangOrError(r *http.Request) (string, bool) {
	lang := r.URL.Query().Get("lang")
	if lang == "" {
		return c.LangDefault, true
	}
	if !c.SupportedLanguages[lang] {
		return "", false
	}
	return lang, true
}

// Query extracts a query parameter with optional default.
func Query(r *http.Request, key, defaultVal string) string {
	val := r.URL.Query().Get(key)
	if val == "" {
		return defaultVal
	}
	return val
}

// QueryOneOf extracts a query parameter, validates against allowed values.
// Returns the value if valid, or defaultVal if empty/invalid.
func QueryOneOf(r *http.Request, key string, allowed []string, defaultVal string) string {
	val := r.URL.Query().Get(key)
	if val == "" {
		return defaultVal
	}
	for _, a := range allowed {
		if val == a {
			return val
		}
	}
	return defaultVal
}