package handlers

import (
	"cs-bridge/internal/http/middleware"
	"cs-bridge/internal/oauth"
	"net/http"

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

func OauthLogin(mgr *oauth.Manager) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		name := chi.URLParam(r, "provider")
		p, err := mgr.Get(name)
		if err != nil {
			http.Error(w, err.Error(), 404)
			return
		}

		state := oauth.NewState()
		session, err := middleware.GetSession(r)
		session.Values["oauth_state"] = state
		session.Values["oauth_provider"] = name
		session.Save(r, w)

		redirectURL, _ := p.AuthURL(state)

		http.Redirect(w, r, redirectURL, http.StatusFound)
	}
}

func OauthCallBack(mgr *oauth.Manager) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		name := chi.URLParam(r, "provider")
		p, err := mgr.Get(name)
		if err != nil {
			http.Error(w, err.Error(), 404)
			return
		}

		session, _ := middleware.GetSession(r)
		expectedState, ok := session.Values["oauth_state"].(string)
		if !ok {
			http.Error(w, "missing oauth state", 400)
			return
		}

		goState := r.URL.Query().Get("state")
		if goState != expectedState {
			http.Error(w, "invaild oauth state2", 400)
			return
		}

		delete(session.Values, "oauth_state")

		code := r.URL.Query().Get("code")
		token, err := p.Exchange(code)
		if err != nil {
			http.Error(w, err.Error(), 404)
			return
		}

		userInfo, err := p.UserInfo(token)
		if err != nil {
			http.Error(w, err.Error(), 500)
			return
		}

		// 只保存用户ID，避免session过大
		session.Values["uid"] = userInfo.UserId
		session.Values["username"] = userInfo.Username

		// 获取登录前保存的URL
		redirectURL := "/"
		if savedURL, ok := session.Values["redirect_after_login"].(string); ok && savedURL != "" {
			redirectURL = savedURL
			delete(session.Values, "redirect_after_login") // 使用后删除
		}

		session.Save(r, w)

		http.Redirect(w, r, redirectURL, http.StatusFound)
	}
}