package main

import (
	"fmt"
	"net/http"
	"github.com/mattermost/mattermost-server/plugin"
	"github.com/mattermost/mattermost-server/model"
	"github.com/pkg/errors"
	"sync"
	"reflect"
	"github.com/google/go-cmp/cmp"
	"os"
	"github.com/fatih/structs"
	"github.com/hashicorp/go-multierror"
	"github.com/kr/pretty"
	"strings"
	"regexp"
	"strconv"
	"time"
	"github.com/fsnotify/fsnotify"
	"io/ioutil"
	"html"
	"encoding/json"
)

var userSplit *regexp.Regexp = regexp.MustCompile(`\s+(^|[^,])|\s*,\s*`)

type Config struct {
	NumDoors string
	WatchPath string
	AdminUsers string
	numDoors uint8
}

func (c *Config) configMap() map[string]interface{} {
	var configMap map[string]interface{} = structs.Map(c)
	var lowerConfigMap map[string]interface{} = make(map[string]interface{})
	for k, v := range(configMap) {
		lowerConfigMap[strings.ToLower(k)] = fmt.Sprintf("%v", v)
	}

	return lowerConfigMap
}

type BathroomMonitorPlugin struct {
	plugin.MattermostPlugin
	config *Config
	adminUsers []string
	configLock sync.RWMutex
	configChanged chan struct{}
	doors map[uint8]bool
	configUpdates int
	lastReport *string
}

func (p *BathroomMonitorPlugin) initDoors() {
	p.doors = make(map[uint8]bool)
	for i := uint8(0); i < p.config.numDoors; i++ {
		p.doors[i] = false
	}
}

func (p *BathroomMonitorPlugin) init() *BathroomMonitorPlugin {
	p.config = &Config{NumDoors: "1", WatchPath: "./", numDoors: 1, AdminUsers:""}
	p.configChanged = make(chan struct{})

	p.initDoors()

	return p;
}

func (p *BathroomMonitorPlugin) ServeHTTP(c *plugin.Context, w http.ResponseWriter, r *http.Request) {
	if r.URL.Path == "/status" {
		var write map[string]string = make(map[string]string)
		for d, s := range p.doors {
			val := "open"
			if s {
				val = "closed"
			}
			write[fmt.Sprintf("%d", d + 1)] = val
		}
		if output, err := json.Marshal(write); err == nil {
			fmt.Fprint(w, string(output))
		} else {
			fmt.Fprint(w, html.EscapeString(err.Error()))
		}
		return
	}
	http.NotFound(w, r)
}

func (p *BathroomMonitorPlugin) confChangedEvent() {
	select {
	case p.configChanged <- struct{}{}:
	default:
	}
}

func (p *BathroomMonitorPlugin) checkCorrectConfig() {
	var currentConfig map[string]interface{} = p.getLowerCasePluginConfig()
	var goodConfig map[string]interface{} = p.config.configMap()
	if !cmp.Equal(currentConfig, goodConfig) {
		p.API.LogInfo(fmt.Sprintf("%d: Saving un-matching config\n%# v\n%# v", p.configUpdates, pretty.Formatter(currentConfig), pretty.Formatter(goodConfig)))
		p.API.SavePluginConfig(goodConfig)
	}
}

func (p *BathroomMonitorPlugin) getLowerCasePluginConfig() map[string]interface{} {
	var currentConfig map[string]interface{} = p.API.GetPluginConfig()
	var lowerConfig map[string]interface{} = make(map[string]interface{})
	for k, v := range(currentConfig) {
		lowerConfig[strings.ToLower(k)] = fmt.Sprintf("%v", v)
	}
	return lowerConfig
}

func (p *BathroomMonitorPlugin) postAdminChannel(text string) {
	p.API.LogError(text)
	if p.lastReport != nil && *p.lastReport == text {
		return
	}
	p.lastReport = &text
	var users []*model.User = make([]*model.User, 0, len(p.adminUsers))
	for _, un := range(p.adminUsers) {
		u, _ := p.API.GetUserByUsername(un)
		if u != nil {
			users = append(users, u)
		}
	}
	
	if len(users) > 0 {
		admin := users[0]
		bots, _ := p.API.GetBots(&model.BotGetOptions{Page:0, PerPage:1000})
		var bathroom_bot *model.Bot = nil
		if bots != nil {
			for _, b := range(bots) {
				if b.Username == "bathroom-bot" {
					bathroom_bot = b
					break
				}
			}
		}

		if bathroom_bot == nil {
			created_bathroom_bot, err := p.API.CreateBot(&model.Bot{Username:"bathroom-bot", OwnerId:admin.Id, DisplayName:"Bathroom Bot", Description:"Tracks Bathroom Status"})
			if err != nil {
				p.API.LogError(errors.Wrap(err, "Couldn't create bathroom-bot bot").Error())
				return
			}
			bathroom_bot = created_bathroom_bot
		}

		if bathroom_bot == nil {
			p.API.LogError("Really couldn't create bathroom-bot bot")
			return
		}
		
		for _, u := range(users) {
			channel, err := p.API.GetDirectChannel(bathroom_bot.UserId, u.Id);
			if err != nil {
				p.API.LogError(errors.Wrap(err, fmt.Sprintf("Couldn't get direct channel to user %s", u.Username)).Error())
				continue
			}
			p.API.CreatePost(&model.Post{UserId: bathroom_bot.UserId, ChannelId:channel.Id, Message:text, MessageSource:text})
		}
	} else {
		p.API.LogError("No admin users?")
	}
}

func (p *BathroomMonitorPlugin) OnConfigurationChange() error {
	p.configLock.Lock()
	defer p.configLock.Unlock()

	//var currentConfig map[string]interface{} = p.getLowerCasePluginConfig()
	//if cmp.Equal(currentConfig, p.config.configMap()) {
	//	p.API.LogInfo(fmt.Sprintf("%d: Skipping matching config", p.configUpdates))
	//	return nil
	//}

	//defer p.checkCorrectConfig()

	var newConfig *Config = new(Config);
	if err := p.API.LoadPluginConfiguration(newConfig); err != nil {
		newErr := errors.Wrap(err, fmt.Sprintf("%d: Failed to load configuration", p.configUpdates))
		p.postAdminChannel(newErr.Error())
		return newErr
	}

	//p.API.LogInfo(fmt.Sprintf("Loaded %t %t", newConfig != nil, p.config != nil))

	if newConfig == nil || newConfig == p.config || reflect.ValueOf(*newConfig).NumField() == 0 {
		p.API.LogInfo("Passed same config, or empty?")
		return nil;
	}

	//p.API.LogInfo("Checked dupe")
	var configErr error = nil

	if _, err := os.Stat(newConfig.WatchPath); err != nil {
		newConfig.WatchPath = "./"
		configErr = multierror.Append(configErr, errors.Wrap(err, "Invalid watch path"))
	}

	//p.API.LogInfo("Checked path")

	numDoors, err := strconv.ParseUint(newConfig.NumDoors, 10, 8)
	if err != nil {
		//p.API.LogError("Bad doors! " + err.Error())
		newConfig.NumDoors = "1"
		newConfig.numDoors = 1
		configErr = multierror.Append(configErr, errors.Wrap(err, "Invalid number of doors"))
	} else {
		//p.API.LogError(fmt.Sprintf("Good doors! %d", numDoors))
		newConfig.numDoors = uint8(numDoors)
	}

	p.config = newConfig

	p.adminUsers = make([]string, 0, 4)
	
	split := userSplit.Split(newConfig.AdminUsers, -1)
	for _, un := range split {
		trimmed := strings.Trim(un, ", \t\n")
		if trimmed != "" {
			p.adminUsers = append(p.adminUsers, trimmed)
		}
	}

	p.configUpdates++

	p.initDoors()

	p.API.LogInfo(fmt.Sprintf("%d: Config: %d %s", p.configUpdates, p.config.numDoors, p.config.WatchPath))

	if configErr != nil {
		p.postAdminChannel(configErr.Error())
	}

	p.confChangedEvent()

	return configErr
}

func watchLoop(p *BathroomMonitorPlugin) {
	doorFile, err := regexp.Compile(`(^|/)door(\d+)$`)
	if err != nil {
		p.API.LogError(errors.Wrap(err, "Couldn't compile regex").Error())
		return
	}

	for {
		p.configLock.Lock()
		numDoors := p.config.numDoors
		watchPath := p.config.WatchPath
		p.configLock.Unlock()

		_ = numDoors

		watcher, err := fsnotify.NewWatcher()
		if err != nil {
			p.API.LogError(errors.Wrap(err, "Couldn't make watcher").Error())
			time.Sleep(60)
			continue
		}

		err = watcher.Add(watchPath)

		if err != nil {
			p.API.LogError(errors.Wrap(err, "Couldn't watch WatchPath").Error())
		}

		run := true
		for ;run; {
			select {
			case event, ok := <- watcher.Events:
				if (!ok) {
					p.API.LogError(errors.Wrap(err, "Couldn't get fsnotify event").Error())
					time.Sleep(60)
					run = false
				} else {
					match := doorFile.FindStringSubmatch(event.Name)
					if match != nil {
						id64, err := strconv.ParseUint(match[2], 10, 8)
						_ = id64
						if err == nil {
							id := uint8(id64)
							if id >= 1 && id <= numDoors {
								if event.Op & fsnotify.Write == fsnotify.Write || event.Op & fsnotify.Create == fsnotify.Create {
									if statusBytes, err := ioutil.ReadFile(event.Name); err == nil {
										status := string(statusBytes)
										if len(status) > 0 {
											p.postAdminChannel("STATUS: " + event.Name + " = " + status)
											doorSensor := strings.Trim(status, " \t\n") == "1"
											p.doors[id - 1] = doorSensor
										}
									} else {
										p.API.LogError(errors.Wrap(err, "Couldn't read door file").Error())
									}
								}
							}
						} else {
							p.API.LogError(errors.Wrap(err, "ParseUint error").Error())
						}
					}
				}
			case <- p.configChanged:
				p.API.LogInfo(fmt.Sprintf("CONFIG CHANGED, RESTARTING %d", p.configUpdates))
				run = false
			}
		}

		watcher.Close()
	}
}


func (p *BathroomMonitorPlugin) OnActivate() error {
	go watchLoop(p)
	return nil
}

func main() {
	plugin.ClientMain((&BathroomMonitorPlugin{}).init())
}