package handler

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

func writeJSON(w http.ResponseWriter, status int, v any) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(v)
}

func writeError(w http.ResponseWriter, status int, msg string) {
	writeJSON(w, status, map[string]string{"error": msg})
}

func writeInternalError(w http.ResponseWriter, r *http.Request, err error, msg string) {
	slog.Error("http error", "method", r.Method, "path", r.URL.Path, "err", err)
	writeError(w, http.StatusInternalServerError, msg)
}

func decodeJSON(r *http.Request, v any) error {
	defer r.Body.Close()
	return json.NewDecoder(r.Body).Decode(v)
}

func csvHeader(r *http.Request, key string) []string {
	raw := r.Header.Get(key)
	if raw == "" {
		return nil
	}
	parts := strings.Split(raw, ",")
	out := make([]string, 0, len(parts))
	for _, p := range parts {
		p = strings.TrimSpace(p)
		if p != "" {
			out = append(out, p)
		}
	}
	return out
}