package route

import (
	"context"
	"fmt"
	"net/http"
	"strconv"
	"time"

	"github.com/Dreamacro/clash/adapter"
	"github.com/Dreamacro/clash/adapter/outboundgroup"
	"github.com/Dreamacro/clash/common/utils"
	"github.com/Dreamacro/clash/component/profile/cachefile"
	C "github.com/Dreamacro/clash/constant"
	"github.com/Dreamacro/clash/tunnel"

	"github.com/go-chi/chi/v5"
	"github.com/go-chi/render"
)

var (
	SwitchProxiesCallback func(sGroup string, sProxy string)
)

func proxyRouter() http.Handler {
	r := chi.NewRouter()
	r.Get("/", getProxies)

	r.Route("/{name}", func(r chi.Router) {
		r.Use(parseProxyName, findProxyByName)
		r.Get("/", getProxy)
		r.Get("/delay", getProxyDelay)
		r.Put("/", updateProxy)
	})
	return r
}

func parseProxyName(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		name := getEscapeParam(r, "name")
		ctx := context.WithValue(r.Context(), CtxKeyProxyName, name)
		next.ServeHTTP(w, r.WithContext(ctx))
	})
}

func findProxyByName(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		name := r.Context().Value(CtxKeyProxyName).(string)
		proxies := tunnel.Proxies()
		proxy, exist := proxies[name]
		if !exist {
			render.Status(r, http.StatusNotFound)
			render.JSON(w, r, ErrNotFound)
			return
		}

		ctx := context.WithValue(r.Context(), CtxKeyProxy, proxy)
		next.ServeHTTP(w, r.WithContext(ctx))
	})
}

func getProxies(w http.ResponseWriter, r *http.Request) {
	proxies := tunnel.Proxies()
	render.JSON(w, r, render.M{
		"proxies": proxies,
	})
}

func getProxy(w http.ResponseWriter, r *http.Request) {
	proxy := r.Context().Value(CtxKeyProxy).(C.Proxy)
	render.JSON(w, r, proxy)
}

func updateProxy(w http.ResponseWriter, r *http.Request) {
	req := struct {
		Name string `json:"name"`
	}{}
	if err := render.DecodeJSON(r.Body, &req); err != nil {
		render.Status(r, http.StatusBadRequest)
		render.JSON(w, r, ErrBadRequest)
		return
	}

	proxy := r.Context().Value(CtxKeyProxy).(*adapter.Proxy)
	selector, ok := proxy.ProxyAdapter.(outboundgroup.SelectAble)
	if !ok {
		render.Status(r, http.StatusBadRequest)
		render.JSON(w, r, newError("Must be a Selector"))
		return
	}

	if err := selector.Set(req.Name); err != nil {
		render.Status(r, http.StatusBadRequest)
		render.JSON(w, r, newError(fmt.Sprintf("Selector update error: %s", err.Error())))
		return
	}

	cachefile.Cache().SetSelected(proxy.Name(), req.Name)
	if SwitchProxiesCallback != nil {
		// refresh tray menu
		go SwitchProxiesCallback(proxy.Name(), req.Name)
	}
	render.NoContent(w, r)
}

func getProxyDelay(w http.ResponseWriter, r *http.Request) {
	query := r.URL.Query()
	url := query.Get("url")
	timeout, err := strconv.ParseInt(query.Get("timeout"), 10, 16)
	if err != nil {
		render.Status(r, http.StatusBadRequest)
		render.JSON(w, r, ErrBadRequest)
		return
	}

	expectedStatus, err := utils.NewIntRanges[uint16](query.Get("expected"))
	if err != nil {
		render.Status(r, http.StatusBadRequest)
		render.JSON(w, r, ErrBadRequest)
		return
	}

	proxy := r.Context().Value(CtxKeyProxy).(C.Proxy)

	ctx, cancel := context.WithTimeout(context.Background(), time.Millisecond*time.Duration(timeout))
	defer cancel()

	delay, err := proxy.URLTest(ctx, url, expectedStatus, C.DropHistory)
	if ctx.Err() != nil {
		render.Status(r, http.StatusGatewayTimeout)
		render.JSON(w, r, ErrRequestTimeout)
		return
	}

	if err != nil || delay == 0 {
		render.Status(r, http.StatusServiceUnavailable)
		if err != nil && delay != 0 {
			render.JSON(w, r, err)
		} else {
			render.JSON(w, r, newError("An error occurred in the delay test"))
		}
		return
	}

	render.JSON(w, r, render.M{
		"delay": delay,
	})
}