from .RAIILock import RAIILock


import math
import os
import threading
import time


class TextCanvas:
	
	__DEFAULT_TERMINAL_WIDTH = 80
	__DEFAULT_TERMINAL_HEIGHT = 22
	__TERMINAL_UPDATE_INTERVAL = 1
	
	__DRAW_RESOLUTION = 3
	
	def __init__(self):
		
		self.__terminal_width = self.__DEFAULT_TERMINAL_WIDTH
		self.__terminal_height = self.__DEFAULT_TERMINAL_HEIGHT
		self.__last_terminal_dimensions_update = time.time()
		self._update_terminal_dimensions(force=True)
		
		self.__grid = []
		self.__render_string = ""
		self.__is_dirty = True
		self.__last_render_time = time.time()
		
		self.__lock = threading.RLock()
	
	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.clear(acquire_locks=acquire_locks)
			self._update_render_string(acquire_locks=acquire_locks)
			
			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.__grid_string = s
	
	def get(self, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			self._update_render_if_dirty(acquire_locks=acquire_locks)
			
			return self.__grid_string
	
	def print(self, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			s = self.get(acquire_locks=acquire_locks)
			
			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=acquire_locks)
				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=acquire_locks)
				
				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 = round(x)
			y = round(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._update_terminal_dimensions(acquire_locks=acquire_locks)
			
			self.__grid = []
			
			for y in range(self.__terminal_height):
				
				self.__grid.append([])
				
				for x in range(self.__terminal_width):
					
					self.__grid[y].append(" ")
			
			self.__is_dirty = True
	
	def get_dimensions(self, acquire_locks=True):
		
		with RAIILock(self.__lock, defer=not acquire_locks):
			
			height = len(self.__grid)
			if height == 0:
				width = 0
			else:
				width = len(self.__grid[0])
			
			return width, height
	
	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 now - self.__last_terminal_dimensions_update < self.__TERMINAL_UPDATE_INTERVAL:
				return
			self.__last_terminal_dimensions_update = now
			
			width, height = self.determine_terminal_dimensions()
			
			self.__terminal_width = width
			self.__terminal_height = height
	
	@staticmethod
	def determine_terminal_dimensions():
		
		columns, lines = os.get_terminal_size()
		
		return columns, lines