package main

import (
	"html/template"
	"io"
	"net/http"
	"strconv"
	"sync"

	"github.com/labstack/echo/v4"
	"github.com/labstack/echo/v4/middleware"
	"github.com/labstack/gommon/log"
	"github.com/russross/blackfriday/v2"
	"golang.org/x/net/websocket"
)

type Templates struct {
	templates *template.Template
}

func (t *Templates) Render(w io.Writer, name string, data interface{}, c echo.Context) error {
	return t.templates.ExecuteTemplate(w, name, data)
}

func NewTemplates() *Templates {
	return &Templates{
		templates: template.Must(template.ParseGlob("views/*.html")),
	}
}

type Page struct {
	Boxes map[int]bool
}

func newPage(boxes map[int]bool) Page {
	return Page{
		Boxes: boxes,
	}
}

type Article struct {
	Content template.HTML
}

func newArticle(content template.HTML) Article {
	return Article{
		Content: content,
	}
}

var (
	wsConnections = make(map[*websocket.Conn]bool)
	wsMutex       sync.Mutex
	boxes         = make(map[int]bool, 1000)
)

func broadcastMessage(message string) {
	wsMutex.Lock()
	defer wsMutex.Unlock()
	for conn := range wsConnections {
		if err := websocket.Message.Send(conn, message); err != nil {
			conn.Close()
			delete(wsConnections, conn)
		}
	}
}

func main() {
	e := echo.New()
	e.Renderer = NewTemplates()

	e.Logger.SetLevel(log.DEBUG)
	e.Use(middleware.Logger())

	for i := 0; i < 1000; i++ {
		boxes[i] = false
	}

	page := newPage(boxes)

	e.Static("/images", "images")
	e.Static("/css", "css")

	e.GET("/", func(c echo.Context) error {
		return c.Render(200, "index", page)
	})

	e.GET("/blog", func(c echo.Context) error {
		// Log a test message
		e.Logger.Info("Test log: /we-are-here endpoint called")

		msg := getNotes(c, e.Logger)
		e.Logger.Info(msg)

		htmlContent := blackfriday.Run([]byte(msg))

		article := newArticle(template.HTML(string(htmlContent)))
		return c.Render(http.StatusOK, "article", article)
	})

	e.POST("/box/:id", updateBoxes)
	e.GET("/ws", initWs)

	e.Logger.Fatal(e.Start(":54321"))
}

func updateBoxes(c echo.Context) error {
	id := c.Param("id")
	checked := c.FormValue("checked") == "on"

	index, err := strconv.Atoi(id)
	if err != nil {
		return c.String(http.StatusBadRequest, "Invalid ID")
	}

	boxes[index] = checked

	message := strconv.Itoa(index)
	if checked {
		message += ":+"
	} else {
		message += ":-"
	}

	broadcastMessage(message)

	return c.JSON(200, "[]")
}

func initWs(c echo.Context) error {
	websocket.Handler(func(ws *websocket.Conn) {
		wsMutex.Lock()
		wsConnections[ws] = true
		wsMutex.Unlock()

		for {
			var msg string
			if err := websocket.Message.Receive(ws, &msg); err != nil {
				wsMutex.Lock()
				delete(wsConnections, ws)
				wsMutex.Unlock()
				ws.Close()
				break
			}
		}
	}).ServeHTTP(c.Response(), c.Request())
	return nil
}