package main

import (
	"bytes"
	"embed"
	"encoding/json"
	"fmt"
	"html/template"
	"io/ioutil"
	"log"
	"net/http"
	"strings"
	"time"

	"git.riomhaire.com/gremlin/elizaservice/eliza"
	"git.riomhaire.com/gremlin/elizaservice/facades/cache"
	"git.riomhaire.com/gremlin/elizaservice/infrastructure"
	"github.com/gofrs/uuid"
	"github.com/jaffee/commandeer"

	"github.com/labstack/echo/v4"
	"github.com/labstack/echo/v4/middleware"
)

//go:embed web/*
var web embed.FS

//go:embed templates/*
var templates embed.FS

//go:embed bots/*
var bots embed.FS

var cacheManager cache.BotCache
var cacheTTL int

/***********************************************************************************************
*
 ***********************************************************************************************/
type Main struct {
	BotName  string `help:"What This Bot is Called."`
	Port     int    `help:"What port bot is listening too"`
	Cache    string `help:"What Cache configuration to use - redis format <host>:<port>:<db>"`
	CacheTTL int    `help:"How long cache is allowed to store data in seconds"`
}

/***********************************************************************************************
*
 ***********************************************************************************************/
func NewMain() *Main {
	return &Main{
		BotName:  "Eliza",
		Port:     8070,
		Cache:    "empire:6379:1",
		CacheTTL: 3600,
	}
}

/********************************
This appends to session in cache latest info
*********************************/
func storeConversation(sessionID string, sessionData eliza.SessionData) {

	// Save it as json
	j, _ := json.Marshal(sessionData)
	cacheManager.Store(sessionID, string(j), cacheTTL)
}

/********************************
This retrieves the context from the cache
*********************************/
func retrieveConversation(sessionID, bot, botversion, user string) (sessionData eliza.SessionData) {
	// Lookup session
	jsonValue, found, _ := cacheManager.Retrieve(sessionID, false)

	if !found {
		sessionData = eliza.SessionData{SessionID: sessionID, Bot: bot, BotVersion: botversion, User: user, StartTime: time.Now().UTC().String(), Conversation: make([]eliza.ChatbotInteraction, 0)}
	}
	if found {
		if err := json.Unmarshal([]byte(jsonValue), &sessionData); err != nil {
			sessionData = eliza.SessionData{SessionID: sessionID, Bot: bot, BotVersion: botversion, User: user, StartTime: time.Now().UTC().String(), Conversation: make([]eliza.ChatbotInteraction, 0)}
		}
	}
	return
}

/***********************************************************************************************
* This at the moment ... but it could be one passed in via LTI if available
 ***********************************************************************************************/
func createSession(c echo.Context) string {
	guid, _ := uuid.NewV4()
	sessionID := guid.String()
	return sessionID
}

/***********************************************************************************************
*
 ***********************************************************************************************/
func findPersonality(name string) (personality eliza.Personality, err error) {
	filename := "bots/" + name + ".json"
	jsonFile, err := bots.Open(filename)
	// if we os.Open returns an error then handle it
	if err != nil {
		return
	}
	//	fmt.Println("Successfully Opened ", filename)
	byteValue, _ := ioutil.ReadAll(jsonFile)

	// we initialize our Users array
	personality = eliza.Personality{}

	// we unmarshal our byteArray which contains our
	// jsonFile's content into 'users' which we defined above
	json.Unmarshal(byteValue, &personality)

	// defer the closing of our jsonFile so that we can parse it later on
	defer jsonFile.Close()

	return
}

/***********************************************************************************************
*
 ***********************************************************************************************/
func chantboInteractiontEndpoint(c echo.Context) error {
	// Extract question from GET request
	user := c.QueryParam("user")
	question := c.QueryParam("value")
	botname := c.QueryParam("bot")
	sessionID := c.QueryParam("session")

	// default to eliza
	if len(botname) == 0 {
		botname = "eliza"
	}

	personality, err := findPersonality(strings.ToLower(botname)) // files are in lowercase
	if err != nil {
		return c.String(http.StatusOK, err.Error())
	}
	// Restore Conversation Context
	sessionData := retrieveConversation(sessionID, botname, personality.Version, user)

	// Return Eliza's response's so long as the user doesn't give a quit statement
	chatboxContext := eliza.ChatbotContext{infrastructure.Version, sessionData}
	character := eliza.NewBotPersonality(&personality, &chatboxContext)
	botResponse := character.ReplyTo(question)

	msg := fmt.Sprintf("Bot [%s %s] Session ID [%s] Question [%s] Answer [%s]", botname, personality.Version, sessionID, question, botResponse.Answer)
	fmt.Println(msg)

	// update cache
	// OK addToConversation
	sessionData.Conversation = append(sessionData.Conversation, botResponse)

	storeConversation(sessionID, sessionData)

	// Return Eliza's answer
	return c.String(http.StatusOK, botResponse.Answer)
}

/***********************************************************************************************
*
 ***********************************************************************************************/
func chantbotEndpoint(c echo.Context) error {

	c.Response().WriteHeader(http.StatusOK)
	c.Response().Header().Add("Content-Type", "text/html")

	// Note the call to ParseFS instead of Parse
	personality := c.Param("personality")
	t, err := template.ParseFS(templates, fmt.Sprintf("templates/%s.html", personality))
	if err != nil {
		log.Fatal(err)
	}

	sessionID := createSession(c)

	fmt.Println("Session ID [", sessionID, "] Created")
	var tBuffer bytes.Buffer

	data := struct {
		SessionID  string
		Id         string
		GivenName  string
		FamilyName string
		Name       string
		Bot        string
	}{
		SessionID:  sessionID,
		Id:         c.QueryParam("user_id"),
		GivenName:  c.QueryParam("given_name"),
		FamilyName: c.QueryParam("family_name"),
		Name:       c.QueryParam("name"),
		Bot:        strings.Title(strings.ToLower(personality)),
	}
	// respond with the output of template execution
	t.Execute(&tBuffer, data)
	page := tBuffer.String()
	return c.String(http.StatusOK, page)
}

/***********************************************************************************************
*
 ***********************************************************************************************/
func (m *Main) Run() error {

	fmt.Println(`
███████╗██╗     ██╗███████╗ █████╗ 
██╔════╝██║     ██║╚══███╔╝██╔══██╗
█████╗  ██║     ██║  ███╔╝ ███████║
██╔══╝  ██║     ██║ ███╔╝  ██╔══██║
███████╗███████╗██║███████╗██║  ██║
╚══════╝╚══════╝╚═╝╚══════╝╚═╝  ╚═╝`)
	fmt.Println("Application Version : ", infrastructure.Version)
	// Create Cache Manager (redis)
	cacheManager = cache.NewRedisCache(m.Cache)
	cacheTTL = m.CacheTTL

	e := echo.New()
	e.Use(middleware.CORS())

	var contentHandler = echo.WrapHandler(http.FileServer(http.FS(web)))
	var contentRewrite = middleware.Rewrite(map[string]string{"/*": "/web/$1"})

	e.GET("/*", contentHandler, contentRewrite)
	e.GET("/user-input", chantboInteractiontEndpoint)
	e.GET("/chatbot/:personality", chantbotEndpoint)
	e.Logger.Fatal(e.Start(fmt.Sprintf(":%d", m.Port)))

	return nil
}

/***********************************************************************************************
*
 ***********************************************************************************************/
func main() {
	err := commandeer.Run(NewMain())
	if err != nil {
		fmt.Println(err)
	}
}