from .RAIILock import RAIILock


from collections import deque
import math
import os
import threading
import time


class TextCanvas:
	
	__DEFAULT_WIDTH = 80
	__DEFAULT_HEIGHT = 22
	__TERMINAL_UPDATE_INTERVAL = 1
	
	__BACKGROUND_CHARACTER = " "
	
	__DRAW_RESOLUTION = 3
	__DEFAULT_TEXT_HEIGHT_TO_WIDTH_RATIO = 2.0
	
	__MAX_FPS_SAMPLES = 100
	
	def __init__(
		self,
		output_width=None, output_height=None, text_to_height_width=None,
		auto_adjust_to_terminal=True,
		print_upward=True
	):
		
		self.__lock = threading.RLock()
		
		# Real dimensions
		if output_width is None:
			output_width = self.__DEFAULT_WIDTH
		if output_height is None:
			output_height = self.__DEFAULT_HEIGHT
		self.__grid_width = output_width
		self.__grid_height = output_height
		
		# Virtual dimensions
		if text_to_height_width is None:
			text_to_height_width = self.__DEFAULT_TEXT_HEIGHT_TO_WIDTH_RATIO
		self.__text_to_height_width = text_to_height_width
		self.__virtual_width = None
		self.__virtual_height = None
		self._auto_calculate_virtual_dimensions(acquire_locks=False)
		self._update_virtual_ratios(acquire_locks=False)
		
		# Terminal stuff
		self.__terminal_width = 0
		self.__terminal_height = 0
		self.__auto_adjust_to_terminal = auto_adjust_to_terminal
		self.__last_terminal_dimensions_update = time.time()
		if self.__auto_adjust_to_terminal:
			self._update_terminal_dimensions(force=True)
		
		#
		self.__print_upward = print_upward
		
		# Actual grid
		self.__grid = []
		self.__render_string = ""
		self.__is_dirty = True
		self.__last_render_time = time.time()
		self.__last_get_render_time = time.time()
		self.__fps_samples = deque(maxlen=self.__MAX_FPS_SAMPLES)
		
		self.__conveyor_enabled = False
		self.__conveyor_thread = None
		self._start_conveyor()
	
	def __exit__(self, exc_type, exc_val, exc_tb):
		
		self.shutdown()
	
	def shutdown(self):
		
		self._stop_conveyor()
	
	def _start_conveyor(self, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			self._stop_conveyor(acquire_locks=False)
			
			self.__conveyor_enabled = True
			self.__conveyor_thread = threading.Thread(target=self._conveyor)
			self.__conveyor_thread.start()
		
	def _stop_conveyor(self, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			if self.__conveyor_thread:
				
				self.__conveyor_enabled = False
				self.__conveyor_thread.join()
				self.__conveyor_thread = None
	
	def _conveyor(self):
		
		# So far simply does maintenance once per second
		while self.__conveyor_enabled is True:
			
			with RAIILock(self.__lock):
				self.__fps_samples.append(0)
			
			time.sleep(1)
	
	def _update_virtual_ratios(self, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			self.__virtual_height_per_grid_height = self.__virtual_height / self.__grid_height
			self.__virtual_width_per_grid_width = self.__virtual_width / self.__grid_width
	
	def _update_render_if_dirty(self, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			if self.__is_dirty:
				self._update_render(acquire_locks=False)
	
	def _update_render(self, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			self._update_render_string(acquire_locks=False)
			
			self.__last_render_time = time.time()
			self.__is_dirty = False
	
	def _update_render_string(self, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			s = ""
			for line in self.__grid:
				for c in line:
					s += c
				s += "\n"
			
			# Don't need that last line feed
			s = s[:-1]
			
			self.__render_string = s
	
	def get(self, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			self._record_frame_get(acquire_locks=False)
			self._update_render_if_dirty(acquire_locks=False)
			
			return self.__render_string
	
	def _record_frame_get(self, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			if len(self.__fps_samples) == 0:
				return
			
			self.__fps_samples[0] += 1
	
	def get_fps(self, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			if len(self.__fps_samples) == 0:
				return 0
			
			fps = 0
			for f in self.__fps_samples:
				fps += f
			
			fps /= len(self.__fps_samples)
			
			return fps
	
	def print(self, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			self._update_render_if_dirty(acquire_locks=False)
			
			s = ""
			
			# Move the cursor up to compensate
			if self.__print_upward:
				up_count = self.__grid_height
				s += ("\033[F" * up_count)
			
			# Grab render
			s += self.get(acquire_locks=False)
			
			print(s)
	
	def draw_text(self, x, y, text, center=False, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			if not isinstance(text, str):
				text = str(text)
			
			if len(text) == 0:
				return
			
			if center is True:
				x -= len(text) / 2
			x = int(x)
			
			for c in text:
				self.write(x=x, y=y, character=c, acquire_locks=False)
				x += 1
	
	def draw_line(self, start_x, start_y, end_x, end_y, character="*", acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			distance_x = math.fabs(end_x - start_x)
			distance_y = math.fabs(end_y - start_y)
			if distance_x > distance_y:
				distance = distance_x
			else:
				distance = distance_y
			
			direction_x = 1 if end_x > start_x else -1
			direction_y = 1 if end_y > start_y else -1
			
			steps = round(distance * self.__DRAW_RESOLUTION)
			if steps == 0:
				return
			
			increment_x = distance_x / steps
			increment_x *= direction_x
			
			increment_y = distance_y / steps
			increment_y *= direction_y
			
			pos_x = start_x
			pos_y = start_y
			for i in range(steps):
				
				pos_x_rounded = round(pos_x)
				pos_y_rounded = round(pos_y)
				
				self.write(x=pos_x_rounded, y=pos_y_rounded, character=character, acquire_locks=False)
				
				pos_x += increment_x
				pos_y += increment_y
	
	def write(self, x, y, character, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			x, y = self._translate_virtual_to_internal_coordinates(x=x, y=y)
			
			if 0 <= y < len(self.__grid):
				if 0 <= x < len(self.__grid[y]):
					
					self.__grid[y][x] = character
					
					self.__is_dirty = True
	
	def clear(self, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			self._auto_adjust_to_terminal(acquire_locks=False)
			
			self.__grid = []
			
			for y in range(self.__grid_height):
				
				self.__grid.append([])
				
				for x in range(self.__grid_width):
					
					self.__grid[y].append(self.__BACKGROUND_CHARACTER)
			
			self.__is_dirty = True
	
	def get_dimensions(self, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			return self.get_virtual_dimensions()
	
	def get_virtual_dimensions(self, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			return self.__virtual_width, self.__virtual_height
	
	def _get_internal_dimensions(self, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			return self.__grid_width, self.__grid_height
	
	def _translate_virtual_to_internal_coordinates(self, x, y):
		
		x_translated = x / self.__virtual_width_per_grid_width
		y_translated = y / self.__virtual_height_per_grid_height
		
		x_translated = round(x_translated)
		y_translated = round(y_translated)
		
		return x_translated, y_translated
	
	def _is_time_to_update_terminal_dimensions(self):
		
		if self.__auto_adjust_to_terminal:
		
			now = time.time()
			
			if now - self.__last_terminal_dimensions_update > self.__TERMINAL_UPDATE_INTERVAL:
				return True
		
		return False
	
	def _auto_adjust_to_terminal(self, force=False, acquire_locks=True):
		
		if not force and not self.__auto_adjust_to_terminal:
			return
		
		with RAIILock(self.__lock, defer=not acquire_locks):
		
			self._update_terminal_dimensions(acquire_locks=False)
			
			self.__grid_width = self.__terminal_width
			self.__grid_height = self.__terminal_height
			
			self._auto_calculate_virtual_dimensions(acquire_locks=False)
	
	def _auto_calculate_virtual_dimensions(self, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			self.__virtual_width = self.__grid_width
			self.__virtual_height = self.__grid_height * self.__text_to_height_width
			
			self._update_virtual_ratios(acquire_locks=False)
	
	def _update_terminal_dimensions(self, force=False, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			now = time.time()
			
			if force is not False and not self._is_time_to_update_terminal_dimensions():
				return
			self.__last_terminal_dimensions_update = now
			
			width, height = self.determine_terminal_dimensions()
			
			self.__terminal_width = width
			self.__terminal_height = height - 1
			
			self._auto_calculate_virtual_dimensions(acquire_locks=False)
	
	@staticmethod
	def determine_terminal_dimensions():
		
		columns, lines = os.get_terminal_size()
		
		return columns, lines