# 
# Copyright (C) 2006 Zach Tibbitts <zach@collegegeek.org>
# Copyright (C) 2006 Alon Zakai ('Kripken') <kripkensteiner@gmail.com>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2, or (at your option)
# any later version.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
#

# pytorrent-manager: backend/non-gui routines, that are not part of the core
# pytorrent module. pytorrent itself is mainly an interface to libtorrent,
# with some arrangements of exception classes for Python, etc.; also, some
# additional code that fits in well at the C++ level of libtorrent. All other
# backend routines should be in pytorrent-manager.


import pytorrent_core
import os, shutil
import pickle
import time


# Information for a single torrent

class torrent:
	def __init__(self, filename, save_dir, compact):
		self.filename  = filename
		self.save_dir  = save_dir
		self.compact   = compact

		self.user_paused     = False # start out unpaused
		self.uploaded_memory = 0


## SAve pause state in here, or in libtorrent...?


		self.filter_out = []

		self.delete_me = False # set this to true, to delete it on next sync


# The persistent state of the torrent system. Everything in this will be pickled

class persistent_state:
	def __init__(self):
		# Basic preferences (use a dictionary, so adding new ones is easy
		self.preferences = {}

		self.max_half_open       = -1
		self.download_rate_limit = -1
		self.upload_rate_limit   = -1
		self.listen_on           = [6881,9999]
		self.max_uploads         = -1 # Per torrent, read the libtorrent docs
		self.max_connections     = 80

		self.use_DHT             = True
		self.base_dir            = "~/Temp"
		self.torrents_subdir     + "torrentfiles"
		self.max_active_torrents = 1
		self.auto_seed_ratio     = -1

		# Prepare queue (queue is pickled, just like everything else)
		self.queue = [] # queue[x] is the unique_ID of the x-th queue position. Simple.

		# Torrents
		self.torrents = []


# The manager for the torrent system

class manager:
	def __init__(self, client_ID, version, user_agent, state_filename):
		self.state_filename = state_filename

		# Ensure directories exist
		if not self.torrents_subdir in os.listdir(self.base_dir):
			os.mkdir(self.base_dir + "/" + self.torrents_subdir)

		# Start up the core
		assert(len(version) == 4)
		pytorrent_core.init(client_ID,
								  int(version[0]),
								  int(version[1]),
								  int(version[2]),
								  int(version[3]),
								  user_agent)

		# Unique IDs are NOT in the state, since they are temporary for each session
		self.unique_IDs = {} # unique_ID -> a torrent object

		# Unpickle the state, or create a new one
		try:
			pkl_file = open(state_filename, 'rb')
			self.state = pickle.load(pkl_file)
			pkl_file.close()

			# Sync with the core: tell core about torrents, and get unique_IDs
			self.sync()
		except IOError:
			self.state = persistent_state()

	def quit(self):
		# Pickle the state
		output = open(self.state_filename, 'wb')
		pickle.dump(self.state, output)
		output.close()

		# Save fastresume data
		self.save_fastresume_data()

		# Shutdown torrent core
		pytorrent.quit()

	def add_torrent(self, filename, save_dir, compact):
		print "add_torrent"
		self.add_torrent_ns(filename, save_dir, compact)
		return self.sync() # Syncing will create a new torrent in the core, and return it's ID

	def remove_torrent(self, unique_ID, data_also):
		# Save some data before we remove the torrent, needed later in this func
		temp = self.unique_IDs[unique_ID]
		temp_fileinfo = pytorrent_core.get_fileinfo(unique_ID)

		self.remove_torrent_ns(unique_ID)
		self.sync()

		# Remove .torrent and  .fastresume
		os.remove(temp.filename)
		try:
			# Must be after removal of the torrent, because that saves a new .fastresume
			os.remove(temp.filename + ".fastresume")
		except OSError:
			pass # Perhaps there never was one to begin with

		# Remove data, if asked to do so
		if data_also:
			# Must be done AFTER the torrent is removed
			# Note: can this be to the trash?
			for filedata in temp_fileinfo:
				filename = filedata['path']
				try:
					os.remove(temp.save_dir + "/" + filename)
				except OSError:
					pass # No file just means it wasn't downloaded, we can continue

	# A separate function, because people may want to call it from time to time
	def save_fastresume_data(self):
		for unique_ID in self.unique_IDs:
			pytorrent_core.save_fastresume(unique_ID, self.unique_IDs[unique_ID].filename)

	def get_state(self, unique_ID):
		return pytorrent_core.get_state(unique_ID)

	def queue_up(self, unique_ID):
		curr_index = self.get_queue_index(unique_ID)
		if curr_index > 0:
			temp = self.state.queue[curr_index - 1]
			self.state.queue[curr_index - 1] = unique_ID
			self.state.queue[curr_index]     = temp

	def queue_down(self, unique_ID):
		curr_index = self.get_queue_index(unique_ID)
		if curr_index < (len(self.state.queue) - 1):
			temp = self.state.queue[curr_index + 1]
			self.state.queue[curr_index + 1] = unique_ID
			self.state.queue[curr_index]     = temp

	def queue_bottom(self, unique_ID):
		curr_index = self.get_queue_index(unique_ID)
		if curr_index < (len(self.state.queue) - 1):
			self.state.queue.remove(curr_index)
			self.state.queue.append(unique_ID)

	def clear_completed(self):
		for unique_ID in self.unique_IDs:
			torrent_state = pytorrent_core.get_state(unique_ID)
			if torrent_state['progress'] == 100.0:
				self.remove_torrent_ns(unique_ID)

		self.sync()

	def set_user_pause(self, unique_ID, new_value):
		self.unique_IDs[unique_ID].user_paused = new_value
		self.apply_queue()

	def is_user_paused(self, unique_ID):
		return self.unique_IDs[unique_ID].user_paused

	def is_paused(self, unique_ID):
		return pytorrent_core.is_paused(unique_ID])

	# Enforce the queue: pause/unpause as needed, based on queue and user_pausing
	# This should be called after changes to relevant parameters (user_pausing, or
	# altering max_active_torrents), or just from time to time
	# ___ALL queuing code should be in this function, and ONLY here___
	def apply_queue(self):
		# Handle autoseeding - downqueue as needed

		if self.auto_seed_ratio != -1:
			for unique_ID in self.unique_IDs:
				if pytorrent_core.is_seeding(unique_ID):
					torrent_state = pytorrent_core.get_state(unique_ID)
					ratio = self.calc_ratio(unique_ID, torrent_state)
					if ratio >= self.auto_seed_ratio:
						self.queue_bottom(unique_ID)

		# Pause and resume torrents
		for index in range(len(self.state.queue)):
			unique_ID = self.state.queue[index]
			if (index < self.state.max_active_torrents or self.state_max_active_torrents == -1)
				and self.is_paused(unique_ID)
				and not self.is_user_paused(unique_ID):
				pytorrent_core.resume(unique_ID)
			elif not self.is_paused(unique_ID) and
					(index >= self.state.max_active_torrents or self.is_user_paused(unique_ID)):
				pytorrent_core.pause(unique_ID)

	def calc_ratio(self, unique_ID, torrent_state):
		up = float(torrent_state['total_upload'] + self.unique_IDs[unique_ID].uploaded_memory
		down = float(torrent_state["total_done"])
					
		try:
			ret = float(up/down)
		except:
			ret = -1

		return ret


	####################
	# Internal functions
	####################

	# Non-syncing functions. Used when we loop over such events, and sync manually at the end

	def add_torrent_ns(self, filename, save_dir, compact):
		# Cache torrent file
		(temp, torrent_file_short) = os.path.split(filename)

		time.sleep(0.01) # Ensure we use a unique time for the new filename
		new_name      = str(time.time()) + ".torrent"
		full_new_name = self.state.base_dir + "/" + self.torrents_subdir + newName

		if new_name in os.listdir(self.state.base_dir + "/" + self.torrents_subdir):
			raise PyTorrentCoreError("Could not cache torrent file locally, failed: " + new_name)

		shutil.copy(filename, full_new_name)

		# Create torrent object
		new_torrent = torrent(full_new_name, save_dir, compact)
		self.state.torrents.append(new_torrent)

	def remove_torrent_ns(self, unique_ID):
		self.unique_IDs[unique_ID].delete_me = True

	# Sync the state.torrents and unique_IDs lists with the core
	# ___ALL syncing code with the core is here, and ONLY here___
	# Also all self-syncing is done here (various lists)

	def sync(self):
		print "sync"

		ret = None # We return new added unique ID(s), or None

		# Add torrents to core and unique_IDs
		torrents_with_unique_ID = self.unique_IDs.values()

		for torrent in self.state.torrents:
			if torrent not in torrents_with_unique_ID:
				print "Adding torrent to core:", torrent.filename, torrent.save_dir, torrent.compact
				unique_ID = pytorrent_core.add_torrent(torrent.filename,
																	torrent.save_dir,
																	torrent.compact)
				print "Got unique ID:", unique_ID
				ret = unique_ID
				self.unique_IDs[unique_ID] = torrent

		# Remove torrents from core, unique_IDs and queue
		to_delete = []
		for torrent in self.state.torrents:
			if torrent.delete_me:
				pytorrent_core.remove_torrent(torrent.unique_ID, torrent.filename)
				to_delete.append(torrent.unique_ID)

		for unique_ID in to_delete:
			self.state.torrents.remove(self.unique_IDs[unique_ID])
			self.state.queue.remove(self.unique_IDs[unique_ID])
			del self.unique_IDs[unique_ID]

		# Add torrents to queue - at the end, of course
		for unique_ID in self.unique_IDs:
			if unique_ID not in self.state.queue:
				self.state.queue.append(unique_ID)

		assert(len(self.unique_IDs) == len(self.state.torrents))
		assert(len(self.unique_IDs) == len(self.state.queue))
		assert(len(self.unique_IDs) == pytorrent_core.get_num_torrents())

		return ret

	def get_queue_index(self, unique_ID):
		return self.state.queue.index(unique_ID)