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, _):
		'''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(r'\[\d+-\d+-\d+ \d+:\d+\]', '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()