package main

import (
	"encoding/json"
	"fmt"
	"os"
	"strings"
	"time"
)

const programName = "statbot"

type messageProcessor interface {
	GetName() string
	GetHelp() string
	ProcessMessage(s *Slack, m *Message)
	ProcessAdminMessage(s *Slack, m *Message)
	ProcessUserMessage(s *Slack, m *Message)
	ProcessAdminUserMessage(s *Slack, m *Message)
	ProcessChannelMessage(s *Slack, m *Message)
	ProcessAdminChannelMessage(s *Slack, m *Message)
}

var messageProcessors []messageProcessor

type statProcessor interface {
	GetName() string
	GetStatKeys() []string
	ProcessMessage(m *Message)
	ProcessUserMessage(m *Message)
	ProcessChannelMessage(m *Message)
}

var statProcessors []statProcessor

func main() {
	if len(os.Args) != 2 {
		fmt.Fprintf(os.Stderr, "usage: statbot slack-bot-token\n")
		os.Exit(1)
	}

	var err error
	var slack *Slack

	if err = initDatabase(); err != nil {
		panic(err)
	}

	if slack, err = CreateSlack(os.Args[1]); err != nil {
		panic(err)
	}

	// For now, we're not running the web server
	//statWebMain(slack)
	statBotMain(slack)
}

// This is the main function for the statbot
func statBotMain(slack *Slack) {
	// start a websocket-based Real Time API session
	registerStatProcessor(new(levelUpStatProcessor))
	registerStatProcessor(new(generalStatProcessor))

	registerMessageProcessor(new(generalProcessor))

	fmt.Println("statbot ready, ^C exits")

	writeToLog("== " + time.Now().Format(time.RFC3339) + " - Bot Started ==\n")
	for {
		// read each incoming message
		m, err := slack.getMessage()
		if err == nil {
			processMessage(slack, &m)
		}
	}
	writeToLog("== " + time.Now().Format(time.RFC3339) + " - Bot Stopped ==\n\n")
}

func processMessage(slack *Slack, m *Message) {
	if mb, me := json.Marshal(m); me == nil {
		// Write the JSON representation to the log
		writeToLog(string(mb) + "\n")
	}
	// TODO: Handle reaction_added messages
	// TODO: Handle reaction_removed messages

	if m.Type == "message" {
		for _, proc := range statProcessors {
			proc.ProcessMessage(m)
		}
		for _, proc := range messageProcessors {
			if isAdmin(m.User) {
				proc.ProcessAdminMessage(slack, m)
			}
			proc.ProcessMessage(slack, m)
		}

		// Check if we know who the user is
		usr, err := getUserInfo(m.User)
		// If the user information hasn't been updated in the last day, update it.
		if err != nil || usr.LastUpdated.IsZero() || time.Since(usr.LastUpdated) > (time.Hour*24) {
			if u, ue := slack.getUserInfo(m.User); ue == nil {
				saveUserInfo(u)
			}
		}
		if m.Channel != "" {
			// Check if we know what the channel is
			chnl, err := getChannelInfo(m.Channel)
			// If the channel information hasn't been updated in the last day, update it.
			if err != nil || chnl.LastUpdated.IsZero() || time.Since(chnl.LastUpdated) > (time.Hour*24) {
				// Either we don't have this channel, or it's a direct message
				if c, ce := slack.getChannelInfo(m.Channel); ce != nil {
					// Invalid channel, save as a direct message
					saveUserMessage(m.User, m)
					for _, proc := range statProcessors {
						proc.ProcessUserMessage(m)
					}
					for _, proc := range messageProcessors {
						if isAdmin(m.User) {
							proc.ProcessAdminUserMessage(slack, m)
						}
						proc.ProcessUserMessage(slack, m)
					}
				} else {
					// Save channel info
					saveChannelInfo(c)
					// And save the channel message
					saveChannelMessage(m.Channel, m)
					for _, proc := range statProcessors {
						proc.ProcessChannelMessage(m)
					}
					for _, proc := range messageProcessors {
						proc.ProcessChannelMessage(slack, m)
					}
				}
			}
		}
	}
}

func registerMessageProcessor(b messageProcessor) {
	// Register a Message Processor
	// Make sure that we haven't already registered it
	for _, proc := range messageProcessors {
		if proc.GetName() == b.GetName() {
			panic(fmt.Errorf("Attempted to Re-register Message Processor %s", b.GetName()))
		}
	}
	messageProcessors = append(messageProcessors, b)
}

func registerStatProcessor(b statProcessor) {
	// Register a Statistic Processor
	// First make sure that we don't have any 'key' collisions
	for _, proc := range statProcessors {
		for _, testKey := range proc.GetStatKeys() {
			for _, k := range b.GetStatKeys() {
				if strings.Replace(testKey, "*", "", -1) == strings.Replace(k, "*", "", -1) {
					panic(fmt.Errorf("Stat Key Collision (%s=>%s and %s=>%s)",
						b.GetName(), k,
						proc.GetName(), testKey,
					))
				}
			}
		}
	}
	statProcessors = append(statProcessors, b)
}

func writeToLog(d string) {
	f, err := os.OpenFile("statbot.log", os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0664)
	if err != nil {
		panic(err)
	}
	f.WriteString(d)
	f.Close()
}