import re
import sys
import tempfile
import json
import datetime
import tkinter
import tkinter.filedialog
import tkinter.messagebox
import tkinter.simpledialog

class Text(tkinter.Text):
	"""
	Tkinter Text Widget
	Override that allows to highlight words with regex.
	"""
	def __init__(self, *args, **kwargs):
		tkinter.Text.__init__(self, *args, **kwargs)

	def highlight(self, pattern, tag, start="1.0", stop="end", regex=True):
		"""
		Highlight text matched by "pattern" and apply it the tag "tag"
		Specify "start" and "stop" in order to restrict the search and
		regex=False if pattern is not a regex.
		"""
		start = self.index(start)
		stop = self.index(stop)
		self.mark_set("matchStart", start)
		self.mark_set("matchEnd", start)
		self.mark_set("searchLimit", stop)
		occurrences = tkinter.IntVar()
		while True:
			index = self.search(
				pattern,
				"matchEnd",
				"searchLimit",
				count=occurrences,
				regexp=regex
			)
			if index == "":
				break
			self.mark_set("matchStart", index)
			self.mark_set("matchEnd", "%s+%sc" % (index, occurrences.get()))
			self.tag_add(tag, "matchStart", "matchEnd")

class Application(tkinter.Frame):
	"""Application class"""
	def __init__(self):
		tkinter.Frame.__init__(self, window)
		window.iconify()

		#Vars
		self.temp = tempfile.TemporaryFile(mode="w+t")
		self.text = tkinter.StringVar()
		self.file = ""
		self.opzionifile = {
			"parent": window,
			"filetypes": [("text files", ".txt")],
			"defaultextension": ".txt",
			"initialfile": "file.txt"
		}
		self.opzionichat = {
			"font": ("Monaco", 13),
			"borderwidth": 2,
			"highlightthickness": 0
		}

		#pref management
		try:
			self.prefs = json.load(open("prefs.json"))
		except FileNotFoundError:
			tkinter.messagebox.showwarning(
				"Dropchat",
				"Preferences file non found!",
				detail="Default preferences rebuilt.")
			self.build_prefs()

		#Gestione della window
		window.geometry(self.prefs["geometry"])
		window.configure(background="#a8a8a8")
		window.columnconfigure(1, weight=1)
		window.rowconfigure(0, weight=1)
		window.protocol('WM_DELETE_WINDOW', self.close)
		window.deiconify()
		self.grid()

		#Inizzializzazione
		self.set_title()
		self.widgets()
		self.read()

		#Gestione delle ultime conversazioni
		try:
			self.delete_not_found()
			self.file = self.prefs["chat"][-1]
		except IndexError:
			response = tkinter.messagebox.askquestion(
					"Dropchat",
					"No conversations found.",
					detail="Make a new one?")
			if response == "yes":
				self.new_file()

		#Loop principale
		self.loop()

	#Widget della window
	def widgets(self):
		"""
		Draw window widgets.
		"""
		self.menubar = tkinter.Menu(window)
		self.chat = Text(window,
			width=100, height=30,
			relief="sunken",
			insertbackground="#fff",
			**self.opzionichat)
		self.sidebar = tkinter.Listbox(
			window, width=20,
			borderwidth=0,
			background="#dce0e8")
		self.textbox = tkinter.Entry(
			window, textvariable=self.text,
			**self.opzionichat)
		self.chat.grid(column=1, row=0, sticky="nswe", pady=(6, 3), padx=6)
		self.textbox.grid(column=1, row=1, sticky="nswe", pady=(3, 6), padx=6)
		self.sidebar.grid(column=0, row=0, sticky="nswe", rowspan=2)

		#Bindings
		self.chat.bind("<KeyPress>", "break")
		self.sidebar.bind("<Double-Button-1>", self.switch_file)
		self.sidebar.bind("<Button-2>", self.show_menu)
		self.textbox.bind("<Return>", self.write)

		#Menu bar
		self.menubar = tkinter.Menu(self)
		menu = tkinter.Menu(self.menubar)

		#Menu 1
		self.menubar.add_cascade(label="Conversation", menu=menu)
		menu.add_command(label="New file", command=self.new_file)
		menu.add_command(label="Open file...", command=self.open_file)

		#Menu 2
		menu = tkinter.Menu(self.menubar)
		self.menubar.add_cascade(label="Profile", menu=menu)
		menu.add_command(
			label="User name",
			command=lambda: self.edit_prefs(
				"username",
				tkinter.simpledialog.askstring(
					"User name",
					"Insert your name:",
					initialvalue=self.prefs["username"],
					parent=window)))

		#Menu 3
		menu = tkinter.Menu(self.menubar)
		self.menubar.add_cascade(label="Edit", menu=menu)
		menu.add_command(label="Cut",
			command=lambda: window.focus_get().event_generate("<<Cut>>"))
		menu.add_command(label="Copy",
			command=lambda: window.focus_get().event_generate("<<Copy>>"))
		menu.add_command(label="Paste",
			command=lambda: window.focus_get().event_generate("<<Paste>>"))
		window.config(menu=self.menubar)

		#Context menu 1
		self.menu1 = tkinter.Menu(self)
		self.menu1.add_command(label="Open", command=self.switch_file)
		self.menu1.add_command(label="Delete", command=self.delete_file)
		self.menu1.add_separator()
		self.menu1.add_command(label="New file", command=self.new_file)
		self.menu1.add_command(label="Reload",
			command=lambda: self.sidebar.delete(0, "end"))

		#Contextmenu 2
		self.menu2 = tkinter.Menu(self)
		self.menu2.add_command(label="New file", command=self.new_file)
		self.menu2.add_command(label="Reload",
			command=lambda: self.sidebar.delete(0, "end"))

	def read(self):
		"""
		Reads the current file from the buffer 
		and writes it into the chat.
		"""
		self.update()
		self.temp.seek(0)
		self.chat.delete(0.0, "end")
		self.chat.insert("end", self.temp.read())
		self.highlight()

	def write(self, event):
		"""Write a message in the current file"""
		if self.file != "":
			with open(self.file, "a") as file:
				if self.text.get() != "":
					row = "[%s] %s: %s\n" % (
						datetime.datetime.now().strftime("%d-%m-%y %H:%M"),
						self.prefs["username"],
						self.text.get())
					self.text.set("")
					file.write(row)

	def update(self):
		"""Copy file into the buffer"""
		self.temp.seek(0)
		self.temp.truncate()
		if self.file != "":
			with open(self.file) as text:
				self.temp.write(text.read())

	def set_title(self):
		"""Update window's title to match current conversation"""
		file = re.search("([^/]*)$", self.file)
		if self.file == "":
			window.title("Dropchat")
		else:
			window.title("Dropchat - " + file.group(0))

	def highlight(self):
		"""
		Highlight semantic parts in the text chat.
		(Date, username and others)
		"""
		self.chat.tag_configure("date", foreground="#005d8f")
		self.chat.tag_configure("name", foreground="#648f00")
		self.chat.tag_configure("other", foreground="#de7a31")
		self.chat.highlight("\[\d+-\d+-\d+ \d+:\d+\]", "data")
		for name in re.findall(" ([a-zA-Z]+): ", self.chat.get(0.0, "end")):
			if name == self.prefs["username"]:
				self.chat.highlight(name, "name")
			else:
				self.chat.highlight(name, "other")

	def show_menu(self, event):
		"""Manages the opening and positioning of context menu"""
		self.sidebar.index = self.sidebar.nearest(event.y)
		if self.sidebar.index < 0:
			self.menu2.post(event.x_root, event.y_root)
			return
		self.sidebar.activate(self.sidebar.index)
		_, offset, _, height = self.sidebar.bbox(self.sidebar.index)
		if event.y > height + offset + self.sidebar.size():
			self.menu2.post(event.x_root, event.y_root)
		else:
			self.menu1.post(event.x_root, event.y_root)

	def recent_files(self):
		"""Inserts recently opened files into the sidebar"""
		for x, file in enumerate(self.prefs["chat"]):
			file = "  - " + re.search("([^/]*)$", file).group(0)
			if file not in self.sidebar.get(x):
				self.sidebar.insert(x, file)

	def delete_file(self):
		"""Removes the currently selected file from the sidebar"""
		if self.prefs["Chat"][self.sidebar.index] == self.file:
			self.file = ""
		del self.prefs["Chat"][self.sidebar.index]
		json.dump(self.prefs, open("prefs.json", "w"))
		self.read()
		self.set_title()

	def switch_file(self, _=None):
		"""Opens the currently selected file from the sidebar in the chat"""
		file = self.prefs["chat"][int(self.sidebar.curselection()[0])]
		if self.file != file:
			self.file = file
			self.read()
			self.set_title()

	def open_file(self):
		"""Selects a new file and opens it in the chat."""
		if sys.platform == "darwin":
			file = tkinter.filedialog.askopenfilename(
				title="Choose a file...",
				message="Open a conversation.",
				**self.opzionifile)
		else:
			file = tkinter.filedialog.askopenfilename(
				title="Choose a file...",
				**self.opzionifile)
		if file not in self.prefs["Chat"] and file != "":
			self.prefs["chat"] += file,
			json.dump(self.prefs, open("prefs.json", "w"))
		self.file = file
		self.read()
		self.set_title()

	def new_file(self):
		"""Creates a new file and opens it in the chat"""
		if sys.platform == "darwin":
			file = tkinter.filedialog.asksaveasfilename(
				title="Create a file...",
				message="Select the name of the new conversation.",
				**self.opzionifile)
		else:
			file = tkinter.filedialog.asksaveasfilename(
				title="Creates a new file...",
				**self.opzionifile)
		if file != "":
			self.file = file
			open(self.file, "w").close()
			if self.file not in self.prefs["chat"]:
				self.prefs["chat"] += self.file,
				json.dump(self.prefs, open("prefs.json", "w"))
			self.read()
			self.set_title()

	def delete_not_found(self):
		"""Removes files that are no longer available"""
		for x, file in enumerate(self.prefs["chat"]):
			try:
				open(file)
				self.file = file
			except FileNotFoundError:
				del self.prefs["Chat"][x]
				continue
		json.dump(self.prefs, open("prefs.json", "w"))

	def build_prefs(self):
		"""Rebuild default preferences"""
		default = {
				"username": "user",
				"chat": ["chat.txt"],
				"geometry": "800x500+500+250"
		}
		json.dump(default, open("prefs.json", "w"))
		self.prefs = json.load(open("prefs.json"))

	def edit_prefs(self, key, pref):
		"""Changing a preference and saves it into an external file."""
		if pref != "":
			self.prefs[key] = pref
			json.dump(self.prefs, open("prefs.json", "w"))

	def close(self):
		"""
		Save the geometry of the window for the next boot, 
		closes and deletes the cache, 
		closes the window and exits.
		"""
		self.edit_prefs("geometry", window.geometry())
		self.temp.close()
		window.destroy()

	def loop(self):
		"""
		Main loop
		Update recent files and current covnersation.
		"""
		self.recent_files()
		self.read()
		self.after(200, self.loop)

window = tkinter.Tk()
app = Application()
app.mainloop()