// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
// See LICENSE.txt for license information.

package web

import (
	"net/http"
	"path"
	"strings"

	"github.com/avct/uasurfer"
	"github.com/gorilla/mux"

	"github.com/mattermost/mattermost/server/public/model"
	"github.com/mattermost/mattermost/server/public/shared/mlog"
	"github.com/mattermost/mattermost/server/v8/channels/app"
	"github.com/mattermost/mattermost/server/v8/channels/utils"
)

type Web struct {
	srv        *app.Server
	MainRouter *mux.Router
}

func New(srv *app.Server) *Web {
	mlog.Debug("Initializing web routes")

	web := &Web{
		srv:        srv,
		MainRouter: srv.Router,
	}

	web.InitOAuth()
	web.InitWebhooks()
	web.InitSaml()
	web.InitStatic()

	return web
}

// Due to the complexities of UA detection and the ramifications of a misdetection
// only older Safari and IE browsers throw incompatibility errors.
// Map should be of minimum required browser version.
// -1 means that the browser is not supported in any version.
var browserMinimumSupported = map[string]int{
	"BrowserIE":     12,
	"BrowserSafari": 12,
}

func CheckClientCompatibility(agentString string) bool {
	ua := uasurfer.Parse(agentString)

	if version, exist := browserMinimumSupported[ua.Browser.Name.String()]; exist && (ua.Browser.Version.Major < version || version < 0) {
		return false
	}

	return true
}

func Handle404(a *app.App, w http.ResponseWriter, r *http.Request) {
	err := model.NewAppError("Handle404", "api.context.404.app_error", nil, "", http.StatusNotFound)
	ipAddress := utils.GetIPAddress(r, a.Config().ServiceSettings.TrustedProxyIPHeader)
	mlog.Debug("not found handler triggered", mlog.String("path", r.URL.Path), mlog.Int("code", 404), mlog.String("ip", ipAddress))
	if IsAPICall(a, r) {
		w.Header().Set("Content-Type", "application/json")
		w.WriteHeader(err.StatusCode)
		err.DetailedError = "There doesn't appear to be an api call for the url='" + r.URL.Path + "'.  Typo? are you missing a team_id or user_id as part of the url?"
		if _, writeErr := w.Write([]byte(err.ToJSON())); writeErr != nil {
			mlog.Warn("Error writing 404 response", mlog.Err(writeErr))
		}
	} else if *a.Config().ServiceSettings.WebserverMode == "disabled" {
		http.NotFound(w, r)
	} else {
		utils.RenderWebAppError(a.Config(), w, r, err, a.AsymmetricSigningKey())
	}
}

func IsAPICall(a *app.App, r *http.Request) bool {
	subpath, _ := utils.GetSubpathFromConfig(a.Config())

	return strings.HasPrefix(r.URL.Path, path.Join(subpath, "api")+"/")
}

func IsWebhookCall(a *app.App, r *http.Request) bool {
	subpath, _ := utils.GetSubpathFromConfig(a.Config())

	return strings.HasPrefix(r.URL.Path, path.Join(subpath, "hooks")+"/")
}

func IsOAuthAPICall(a *app.App, r *http.Request) bool {
	subpath, _ := utils.GetSubpathFromConfig(a.Config())

	if r.Method == "POST" && r.URL.Path == path.Join(subpath, "oauth", "authorize") {
		return true
	}

	if r.URL.Path == path.Join(subpath, "oauth", "apps", "authorized") ||
		r.URL.Path == path.Join(subpath, "oauth", "deauthorize") ||
		r.URL.Path == path.Join(subpath, "oauth", "access_token") {
		return true
	}
	return false
}

func ReturnStatusOK(w http.ResponseWriter) {
	m := make(map[string]string)
	m[model.STATUS] = model.StatusOk
	if _, err := w.Write([]byte(model.MapToJSON(m))); err != nil {
		mlog.Warn("Error writing status OK response", mlog.Err(err))
	}
}