// backend/util.go
package main

import (
	"encoding/json"
	"log"
	"net/http"
	"os"
	"strings"
)

func writeJSON(w http.ResponseWriter, v any) {
	w.Header().Set("Content-Type", "application/json")
	if err := json.NewEncoder(w).Encode(v); err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
	}
}

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

func must(err error, msg string) {
	if err != nil {
		log.Fatalf("%s: %v", msg, err)
	}
}

func contains(ss []string, v string) bool {
	for _, s := range ss {
		if s == v {
			return true
		}
	}
	return false
}

func sanitizeSegment(s string) string {
	s = strings.TrimSpace(s)
	s = strings.ReplaceAll(s, " ", "_")
	s = strings.Trim(s, "/")
	if i := strings.IndexByte(s, '/'); i >= 0 {
		s = s[:i]
	}

	out := make([]rune, 0, len(s))
	for _, r := range s {
		switch {
		case r >= 'a' && r <= 'z',
			r >= 'A' && r <= 'Z',
			r >= '0' && r <= '9',
			r == '_',
			r == '-',
			r == '.':
			out = append(out, r)
		default:
			out = append(out, '_')
		}
	}
	if len(out) > 64 {
		out = out[:64]
	}
	return string(out)
}