// Package handlers implements the HTTP handler functions for the Amnezia Share
// Panel web application. Handlers are grouped by domain across several files
// (health.go, install.go, login.go, oidc.go, share.go, cabinet.go, faq.go,
// admin_*.go) but all live in this single package so they can freely share
// small helpers declared in this file.
//
// The package registers itself onto internal/web via web.RegisterRoutes from
// init(), rather than internal/web importing this package directly — that
// would create an import cycle, since this package needs *web.App.
package handlers

import (
	"encoding/json"
	"errors"
	"net/http"
	"strconv"
	"strings"

	"amnezia-share/internal/web"
)

// errUnknownAction is returned by admin/guest POST dispatchers for an
// unrecognized "action" form value.
var errUnknownAction = errors.New("Неизвестное действие.")

func itoaHelper(n int) string {
	return strconv.Itoa(n)
}

func formIntFromString(v string, def int) int {
	v = strings.TrimSpace(v)
	if v == "" {
		return def
	}
	n, err := strconv.Atoi(v)
	if err != nil {
		return def
	}
	return n
}

func init() {
	web.RegisterRoutes(register)
}

// register wires every route of the application onto mux.
func register(a *web.App, mux *http.ServeMux) {
	registerHealth(a, mux)
	registerInstall(a, mux)
	registerLogin(a, mux)
	registerOIDC(a, mux)
	registerShare(a, mux)
	registerCabinet(a, mux)
	registerFAQ(a, mux)
	registerAdmin(a, mux)

	mux.HandleFunc("GET /{$}", func(w http.ResponseWriter, r *http.Request) {
		if a.CurrentAdmin(r) != nil {
			http.Redirect(w, r, a.Cfg.AppURL("admin"), http.StatusSeeOther)
			return
		}
		count, err := a.Auth.AdminCount(r.Context())
		if err != nil || count == 0 {
			http.Redirect(w, r, a.Cfg.AppURL("install"), http.StatusSeeOther)
			return
		}
		http.Redirect(w, r, a.Cfg.AppURL("login"), http.StatusSeeOther)
	})
}

func redirectTo(w http.ResponseWriter, r *http.Request, a *web.App, path string) {
	http.Redirect(w, r, a.Cfg.AppURL(path), http.StatusSeeOther)
}

func wantsJSON(r *http.Request) bool {
	return r.Header.Get("X-Share-Async") == "1" || strings.Contains(r.Header.Get("Accept"), "application/json")
}

func formInt(r *http.Request, key string, def int) int {
	v := strings.TrimSpace(r.FormValue(key))
	if v == "" {
		return def
	}
	n, err := strconv.Atoi(v)
	if err != nil {
		return def
	}
	return n
}

func formInt64(r *http.Request, key string, def int64) int64 {
	v := strings.TrimSpace(r.FormValue(key))
	if v == "" {
		return def
	}
	n, err := strconv.ParseInt(v, 10, 64)
	if err != nil {
		return def
	}
	return n
}

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

func errMsg(err error) string {
	if err == nil {
		return ""
	}
	return err.Error()
}

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

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

func writeJSONOK(w http.ResponseWriter, extra map[string]any) {
	if extra == nil {
		extra = map[string]any{}
	}
	extra["ok"] = true
	writeJSON(w, http.StatusOK, extra)
}