/*
 * MIT License
 *
 * Copyright (c) 2019 Jianhui Zhao <zhaojh329@gmail.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package main

import (
	"net"
	"net/http"
	"sync"
	"sync/atomic"

	"github.com/rs/zerolog/log"
)

type RttyServer struct {
	mu            sync.RWMutex
	groups        sync.Map
	cfg           Config
	httpProxyPort int
}

type DeviceGroup struct {
	devices sync.Map
	count   atomic.Int32
}

func (srv *RttyServer) Run() error {
	log.Debug().Msgf("%+v", srv.cfg)

	if srv.cfg.PprofAddr != "" {
		go srv.ListenPprof()
	}

	go srv.ListenDevices()
	go srv.ListenHttpProxy()

	return srv.ListenAPI()
}

func (srv *RttyServer) ListenPprof() {
	ln, err := net.Listen("tcp", srv.cfg.PprofAddr)
	if err != nil {
		log.Error().Err(err).Msgf("Failed to start pprof server")
		return
	}
	defer ln.Close()

	addr := ln.Addr().(*net.TCPAddr)
	log.Info().Msgf("Starting pprof server on: %s", addr)

	host := addr.IP.String()
	if host == "0.0.0.0" || host == "::" {
		host = "localhost"
	}
	log.Info().Msgf("Access pprof at: http://%s:%d/debug/pprof/", host, addr.Port)

	err = http.Serve(ln, nil)
	if err != nil {
		log.Error().Err(err).Msgf("pprof server failed")
	}
}

func (srv *RttyServer) GetDevice(group, id string) *Device {
	srv.mu.RLock()
	defer srv.mu.RUnlock()

	g := srv.GetGroup(group, false)
	if g == nil {
		return nil
	}

	if v, ok := g.devices.Load(id); ok {
		return v.(*Device)
	}

	return nil
}

func (srv *RttyServer) AddDevice(dev *Device) bool {
	srv.mu.Lock()
	defer srv.mu.Unlock()

	g := srv.GetGroup(dev.group, true)

	if _, loaded := g.devices.LoadOrStore(dev.id, dev); loaded {
		return false
	}

	g.count.Add(1)

	return true
}

func (srv *RttyServer) DelDevice(dev *Device) {
	srv.mu.Lock()
	defer srv.mu.Unlock()

	g := srv.GetGroup(dev.group, false)
	if g == nil {
		return
	}

	if _, loaded := g.devices.LoadAndDelete(dev.id); loaded {
		if g.count.Add(-1) == 0 {
			srv.groups.Delete(dev.group)
		}
	}
}

func (srv *RttyServer) GetGroup(group string, create bool) *DeviceGroup {
	if create {
		val, _ := srv.groups.LoadOrStore(group, &DeviceGroup{})
		return val.(*DeviceGroup)
	} else {
		val, ok := srv.groups.Load(group)
		if !ok {
			return nil
		}
		return val.(*DeviceGroup)
	}
}