package web

import (
	"encoding/json"
	"net/http"
	"strconv"
)

func pathID(r *http.Request, name string) (int64, error) {
	return strconv.ParseInt(r.PathValue(name), 10, 64)
}

// queryOptionalID parses a query parameter as *int64; an empty or missing
// value returns nil (meaning "top level" / "unfiled" in folder/asset
// contexts).
func queryOptionalID(r *http.Request, name string) (*int64, error) {
	v := r.URL.Query().Get(name)
	if v == "" {
		return nil, nil
	}
	id, err := strconv.ParseInt(v, 10, 64)
	if err != nil {
		return nil, err
	}
	return &id, nil
}

func queryInt64(r *http.Request, name string) int64 {
	v := r.URL.Query().Get(name)
	if v == "" {
		return 0
	}
	id, _ := strconv.ParseInt(v, 10, 64)
	return id
}

func queryInt(r *http.Request, name string, def int) int {
	v := r.URL.Query().Get(name)
	if v == "" {
		return def
	}
	n, err := strconv.Atoi(v)
	if err != nil {
		return def
	}
	return n
}

type jsonEnvelope struct {
	OK      bool   `json:"ok"`
	Error   string `json:"error,omitempty"`
	Message string `json:"message,omitempty"`
	Data    any    `json:"data,omitempty"`
}

func writeJSON(w http.ResponseWriter, status int, v jsonEnvelope) {
	w.Header().Set("Content-Type", "application/json; charset=utf-8")
	w.WriteHeader(status)
	_ = json.NewEncoder(w).Encode(v)
}

func jsonOK(w http.ResponseWriter, data any) {
	writeJSON(w, http.StatusOK, jsonEnvelope{OK: true, Data: data})
}

func jsonErr(w http.ResponseWriter, status int, err error) {
	writeJSON(w, status, jsonEnvelope{OK: false, Error: err.Error()})
}

func readJSON(r *http.Request, v any) error {
	dec := json.NewDecoder(r.Body)
	dec.DisallowUnknownFields()
	return dec.Decode(v)
}