package views

import (
	"bufio"
	"crypto/md5"
	"fmt"
	"github.com/thewhitetulip/Tasks/db"
	"io"
	"io/ioutil"
	"log"
	"net/http"
	"os"
	"strconv"
	"strings"
	"text/template"
	"time"
)

var homeTemplate *template.Template
var deletedTemplate *template.Template
var completedTemplate *template.Template
var editTemplate *template.Template
var searchTemplate *template.Template
var templates *template.Template
var message string //message will store the message to be shown as notification
var err error

//PopulateTemplates is used to parse all templates present in
//the templates folder
func PopulateTemplates() {
	var allFiles []string
	templatesDir := "./public/templates/"
	files, err := ioutil.ReadDir(templatesDir)
	if err != nil {
		log.Println(err)
		os.Exit(1) // No point in running app if templates aren't read
	}
	for _, file := range files {
		filename := file.Name()
		if strings.HasSuffix(filename, ".html") {
			allFiles = append(allFiles, templatesDir+filename)
		}
	}

	if err != nil {
		log.Println(err)
		os.Exit(1)
	}
	templates, err = template.ParseFiles(allFiles...)
	if err != nil {
		log.Println(err)
		os.Exit(1)
	}
	homeTemplate = templates.Lookup("home.html")
	deletedTemplate = templates.Lookup("deleted.html")

	editTemplate = templates.Lookup("edit.html")
	searchTemplate = templates.Lookup("search.html")
	completedTemplate = templates.Lookup("completed.html")

}

//ShowAllTasksFunc is used to handle the "/" URL which is the default ons
//TODO add http404 error
func ShowAllTasksFunc(w http.ResponseWriter, r *http.Request) {
	if r.Method == "GET" {
		context := db.GetTasks("pending") //true when you want non deleted notes
		if message != "" {
			context.Message = message
		}
		context.CSRFToken = "abcd"
		message = ""
		expiration := time.Now().Add(365 * 24 * time.Hour)
		cookie := http.Cookie{Name: "csrftoken", Value: "abcd", Expires: expiration}
		http.SetCookie(w, &cookie)
		homeTemplate.Execute(w, context)
	} else {
		message = "Method not allowed"
		http.Redirect(w, r, "/", http.StatusFound)
	}
}

// UploadedFileHandler is used to handle the uploaded file related requests
func UploadedFileHandler(w http.ResponseWriter, r *http.Request) {
	if r.Method == "GET" {
		log.Println("into the handler")
		token := r.URL.Path[len("/files/"):]

		//file, err := db.GetFileName(token)
		//if err != nil {
		log.Println("serving file ./files/" + token)
		http.ServeFile(w, r, "./files/"+token)
		//}
	}
}

//ShowTrashTaskFunc is used to handle the "/trash" URL which is used to show the deleted tasks
func ShowTrashTaskFunc(w http.ResponseWriter, r *http.Request) {
	if r.Method == "GET" {
		context := db.GetTasks("deleted") //false when you want deleted notes
		if message != "" {
			context.Message = message
			message = ""
		}
		deletedTemplate.Execute(w, context)
	} else {
		message = "Method not allowed"
		http.Redirect(w, r, "/", http.StatusFound)
	}
}

//SearchTaskFunc is used to handle the /search/ url, handles the search function
func SearchTaskFunc(w http.ResponseWriter, r *http.Request) {
	if r.Method == "POST" {
		r.ParseForm()
		query := r.Form.Get("query")
		context := db.SearchTask(query)
		searchTemplate.Execute(w, context)
	} else {
		message = "Method not allowed"
		http.Redirect(w, r, "/", http.StatusFound)
	}

	//AddTaskFunc is used to handle the addition of new task, "/add" URL
}
func AddTaskFunc(w http.ResponseWriter, r *http.Request) {
	if r.Method == "POST" { // Will work only for POST requests, will redirect to home
		r.ParseForm()
		file, handler, err := r.FormFile("uploadfile")
		if err != nil {
			log.Println(err)
		}

		taskPriority, priorityErr := strconv.Atoi(r.FormValue("priority"))
		if priorityErr != nil {
			log.Print(priorityErr)
		}
		priorityList := []int{1, 2, 3}
		found := false
		for _, priority := range priorityList {
			if taskPriority == priority {
				found = true
			}
		}
		//If someone gives us incorrect priority number, we give the priority
		//to that task as 1 i.e. Low
		if !found {
			taskPriority = 1
		}
		title := template.HTMLEscapeString(r.Form.Get("title"))
		content := template.HTMLEscapeString(r.Form.Get("content"))
		formToken := template.HTMLEscapeString(r.Form.Get("CSRFToken"))

		cookie, _ := r.Cookie("csrftoken")
		if formToken == cookie.Value {
			if handler != nil {
				r.ParseMultipartForm(32 << 20) //defined maximum size of file
				defer file.Close()
				randomFileName := md5.New()
				io.WriteString(randomFileName, strconv.FormatInt(time.Now().Unix(), 10))
				io.WriteString(randomFileName, handler.Filename)
				token := fmt.Sprintf("%x", randomFileName.Sum(nil))
				f, err := os.OpenFile("./files/"+token, os.O_WRONLY|os.O_CREATE, 0666)
				if err != nil {
					log.Println(err)
					return
				}
				defer f.Close()
				io.Copy(f, file)

				filelink := "<br> <a href=/files/" + token + ">" + handler.Filename + "</a>"
				content = content + filelink

				fileTruth := db.AddFile(handler.Filename, token)
				if fileTruth != nil {
					message = "Error adding filename in db"
					log.Println("error adding task to db")
				}
			}

			taskTruth := db.AddTask(title, content, taskPriority)

			if taskTruth != nil {
				message = "Error adding task"
				log.Println("error adding task to db")
			} else {
				message = "Task added"
				log.Println("added task to db")
			}
			http.Redirect(w, r, "/", http.StatusFound)
		} else {
			log.Fatal("CSRF mismatch")
		}

	} else {
		message = "Method not allowed"
		http.Redirect(w, r, "/", http.StatusFound)
	}
}

//ShowCompleteTasksFunc is used to populate the "/completed/" URL
func ShowCompleteTasksFunc(w http.ResponseWriter, r *http.Request) {
	if r.Method == "GET" {
		context := db.GetTasks("completed") //false when you want finished notes
		completedTemplate.Execute(w, context)
	} else {
		message = "Method not allowed"
		http.Redirect(w, r, "/", http.StatusFound)
	}
}

//EditTaskFunc is used to edit tasks, handles "/edit/" URL
func EditTaskFunc(w http.ResponseWriter, r *http.Request) {
	if r.Method == "GET" {
		id, err := strconv.Atoi(r.URL.Path[len("/edit/"):])
		if err != nil {
			log.Println(err)
		} else {
			task := db.GetTaskByID(id)
			editTemplate.Execute(w, task)
		}
	} else {
		message = "Method not allowed"
		http.Redirect(w, r, "/", http.StatusFound)
	}
}

//CompleteTaskFunc is used to show the complete tasks, handles "/completed/" url
func CompleteTaskFunc(w http.ResponseWriter, r *http.Request) {
	if r.Method == "GET" {
		id, err := strconv.Atoi(r.URL.Path[len("/complete/"):])
		if err != nil {
			log.Println(err)
		} else {
			err = db.CompleteTask(id)
			if err != nil {
				message = "Complete task failed"
			} else {
				message = "Task marked complete"
			}
			http.Redirect(w, r, "/", http.StatusFound)
		}
	} else {
		message = "Method not allowed"
		http.Redirect(w, r, "/", http.StatusFound)
	}
}

//DeleteTaskFunc is used to delete a task, trash = move to recycle bin, delete = permanent delete
func DeleteTaskFunc(w http.ResponseWriter, r *http.Request) {
	if r.Method == "GET" {
		id := r.URL.Path[len("/delete/"):]
		if id == "all" {
			db.DeleteAll()
			http.Redirect(w, r, "/", http.StatusFound)
		} else {
			id, err := strconv.Atoi(id)
			if err != nil {
				log.Println(err)
			} else {
				err = db.DeleteTask(id)
				if err != nil {
					message = "Error deleting task"
				} else {
					message = "Task deleted"
				}
				http.Redirect(w, r, "/", http.StatusFound)
			}
		}
	} else {
		message = "Method not allowed"
		http.Redirect(w, r, "/", http.StatusFound)
	}
}

//TrashTaskFunc is used to populate the trash tasks
func TrashTaskFunc(w http.ResponseWriter, r *http.Request) {
	if r.Method == "GET" {
		id, err := strconv.Atoi(r.URL.Path[len("/trash/"):])
		if err != nil {
			log.Println(err)
		} else {
			err = db.TrashTask(id)
			if err != nil {
				message = "Error trashing task"
			} else {
				message = "Task trashed"
			}
			http.Redirect(w, r, "/", http.StatusFound)
		}
	} else {
		message = "Method not allowed"
		http.Redirect(w, r, "/trash", http.StatusFound)
	}
}

//RestoreTaskFunc is used to restore task from trash, handles "/restore/" URL
func RestoreTaskFunc(w http.ResponseWriter, r *http.Request) {
	if r.Method == "GET" {
		id, err := strconv.Atoi(r.URL.Path[len("/restore/"):])
		if err != nil {
			log.Println(err)
		} else {
			err = db.RestoreTask(id)
			if err != nil {
				message = "Restore failed"
			} else {
				message = "Task restored"
			}
			http.Redirect(w, r, "/deleted/", http.StatusFound)
		}
	} else {
		message = "Method not allowed"
		http.Redirect(w, r, "/", http.StatusFound)
	}
}

//RestoreFromCompleteFunc restores the task from complete to pending
func RestoreFromCompleteFunc(w http.ResponseWriter, r *http.Request) {
	if r.Method == "GET" {
		id, err := strconv.Atoi(r.URL.Path[len("/incomplete/"):])
		if err != nil {
			log.Println(err)
		} else {
			err = db.RestoreTaskFromComplete(id)
			if err != nil {
				message = "Restore failed"
			} else {
				message = "Task restored"
			}
			http.Redirect(w, r, "/pending/", http.StatusFound)
		}
	} else {
		message = "Method not allowed"
		http.Redirect(w, r, "/", http.StatusFound)
	}
}

//UpdateTaskFunc is used to update a task, handes "/update/" URL
func UpdateTaskFunc(w http.ResponseWriter, r *http.Request) {
	if r.Method == "POST" {
		r.ParseForm()
		id, err := strconv.Atoi(r.Form.Get("id"))
		if err != nil {
			log.Println(err)
		}
		title := r.Form.Get("title")
		content := r.Form.Get("content")
		err = db.UpdateTask(id, title, content)
		if err != nil {
			message = "Error updating task"
		} else {
			message = "Task updated"
		}
		http.Redirect(w, r, "/", http.StatusFound)

	} else {
		message = "Method not allowed"
		http.Redirect(w, r, "/", http.StatusFound)
	}
}

//ServeStaticFunc is used to serve static files
//TODO: replace this with the http.FileServer
func ServeStaticFunc(w http.ResponseWriter, r *http.Request) {
	path := "./public" + r.URL.Path
	var contentType string
	if strings.HasSuffix(path, ".css") {
		contentType = "text/css"
	} else if strings.HasSuffix(path, ".png") {
		contentType = "image/png"
	} else if strings.HasSuffix(path, ".js") {
		contentType = "application/javascript"
	} else {
		contentType = "plain/text"
	}

	f, err := os.Open(path)

	if err == nil {
		defer f.Close()
		w.Header().Add("Content Type", contentType)

		br := bufio.NewReader(f)
		br.WriteTo(w)
	} else {
		w.WriteHeader(404)
	}
}