import pygame as pg
import math
from settings import *

class RayCasting():
    def __init__(self, game):
        self.game = game
        self.ray_casting_result = []
        self.objects_to_render = []
        self.textures = self.game.object_renderer.wall_textures
        
    def get_objects_to_render(self):
        self.objects_to_render = []
        for ray, values in enumerate(self.ray_casting_result):
            depth, proj_height, texture, offset = values
            
            if proj_height < HEIGHT:
                wall_column = self.textures[texture].subsurface(
                    offset * (TEXTURE_SIZE - SCALE), 0, SCALE, TEXTURE_SIZE
                )
                wall_column = pg.transform.scale(wall_column, (SCALE, proj_height))
                wall_pos = (ray * SCALE, HALF_HEIGHT - proj_height // 2)
            else:
                texture_height = TEXTURE_SIZE * HEIGHT / proj_height
                wall_column = self.textures[texture].subsurface(
                    offset * (TEXTURE_SIZE - SCALE), HALF_TEXTURE_SIZE - texture_height // 2,
                    SCALE, texture_height
                )
                wall_column = pg.transform.scale(wall_column, (SCALE, HEIGHT))
                wall_pos = (ray * SCALE, 0)
            
            self.objects_to_render.append((depth, wall_column, wall_pos))
        
    def ray_cast(self):
        self.ray_casting_result = []
        ox, oy = self.game.player.pos
        x_map, y_map = self.game.player.map_pos
        
        texture_vert, texture_horz = 1, 1
        
        ray_angle = self.game.player.angle - HALF_FOV + 0.0001 # 0.0001 to avoid division by zero
        for ray in range(NUM_RAYS):
            sin_a = math.sin(ray_angle)
            cos_a = math.cos(ray_angle)
            
            # horizontal
            y_horz, dy = (y_map + 1, 1) if sin_a > 0 else (y_map - 1e-6, -1)
            
            depth_horz = (y_horz - oy) / sin_a
            x_horz = ox + depth_horz * cos_a
            
            delta_depth = dy / sin_a
            dx = delta_depth * cos_a
            
            for i in range(MAX_DEPTH):
                tile_horz = int(x_horz), int(y_horz)
                if tile_horz in self.game.map.world_map:
                    texture_horz = self.game.map.world_map[tile_horz]
                    break
                x_horz += dx
                y_horz += dy
                depth_horz += delta_depth
            
            # verticals
            x_vert, dx = (x_map + 1, 1) if cos_a > 0 else (x_map - 1e-6, -1)
            
            depth_vert = (x_vert - ox) / cos_a
            y_vert = oy + depth_vert * sin_a
            
            delta_depth = dx / cos_a
            dy = delta_depth * sin_a
            
            for i in range(MAX_DEPTH):
                tile_vert = int(x_vert), int(y_vert)
                if tile_vert in self.game.map.world_map:
                    texture_vert = self.game.map.world_map[tile_vert]
                    break
                x_vert += dx
                y_vert += dy
                depth_vert += delta_depth
            
            # Select the shortest distance to the wall, and the corresponding texture
            if depth_vert < depth_horz:
                depth, texture = depth_vert, texture_vert
                y_vert %= 1
                offset = y_vert if cos_a > 0 else (1 - y_vert)
            else:
                depth, texture = depth_horz, texture_horz
                x_horz %= 1
                offset = (1 - x_horz) if sin_a > 0 else x_horz
                
            # Draw the ray for debugging
            if DEBUG_MODE:
                pg.draw.line(self.game.screen, 'yellow', (ox * 100, oy * 100),
                            (100 * ox + 100 * depth * cos_a, 100 * oy + 100 * depth * sin_a), 1)
            
            # Remove fish-eye effect
            if FISH_EYE_FIX:
                depth *= math.cos(self.game.player.angle - ray_angle)
            
            # Projection
            proj_height = SCREEN_DIST / (depth + 0.0001) # 0.0001 to avoid division by zero
            
            # Draw walls
            #colour = [255 / (1 + depth ** 5 * 0.0002)] * 3
            #pg.draw.rect(self.game.screen, colour,
            #             (ray * SCALE, HALF_HEIGHT - proj_height // 2, SCALE, proj_height))
            
            # Ray casting result
            self.ray_casting_result.append((depth, proj_height, texture, offset))
            
            ray_angle += DELTA_ANGLE
        
            
    def update(self):
        self.ray_cast()
        self.get_objects_to_render()