{
 "cells": [
  {
   "cell_type": "markdown",
   "id": "e063ba00",
   "metadata": {},
   "source": [
    "# A* Algorithm"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "868592a7",
   "metadata": {},
   "source": [
    "## Install Requirements"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "26dff129",
   "metadata": {},
   "source": [
    "create a virtual environment in current directory by \n",
    "\n",
    "```\n",
    "python3 -m venv .env    # macos\n",
    "python -m venv .env     # linux\n",
    "```"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 12,
   "id": "55fa613b",
   "metadata": {
    "ExecuteTime": {
     "end_time": "2025-05-07T21:40:23.660320Z",
     "start_time": "2025-05-07T21:40:22.973705Z"
    }
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Requirement already satisfied: pygame in /home/safak/Dokumente/Uni/KI/.env/lib64/python3.13/site-packages (2.6.1)\n",
      "Note: you may need to restart the kernel to use updated packages.\n"
     ]
    }
   ],
   "source": [
    "%pip install pygame"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "db35c098",
   "metadata": {},
   "source": [
    "## Imports"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 13,
   "id": "e7034eee",
   "metadata": {
    "ExecuteTime": {
     "end_time": "2025-05-07T21:40:23.825797Z",
     "start_time": "2025-05-07T21:40:23.718944Z"
    }
   },
   "outputs": [],
   "source": [
    "import pygame\n",
    "import math"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "77d18f1b",
   "metadata": {},
   "source": [
    "## Global Variables"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 14,
   "id": "60b63344",
   "metadata": {
    "ExecuteTime": {
     "end_time": "2025-05-07T21:40:23.877569Z",
     "start_time": "2025-05-07T21:40:23.873797Z"
    }
   },
   "outputs": [],
   "source": [
    "BLACK = (0, 0, 0)\n",
    "WHITE = (255, 255, 255)\n",
    "BLUE = (0, 0, 255)\n",
    "GREEN = (0, 255, 0)\n",
    "RED = (255, 0, 0)\n",
    "ORANGE = (255, 165, 0)\n",
    "GREY = (128, 128, 128)\n",
    "\n",
    "WIDTH = 25\n",
    "HEIGHT = 25\n",
    "MARGIN = 3\n",
    "GRID_SIZE= 20"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "87a05a3b",
   "metadata": {},
   "source": [
    "## Classes \n",
    "\n",
    "The Queue Class is the same from Task 1"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 15,
   "id": "84ad596c",
   "metadata": {
    "ExecuteTime": {
     "end_time": "2025-05-07T21:40:24.013443Z",
     "start_time": "2025-05-07T21:40:24.010202Z"
    }
   },
   "outputs": [],
   "source": [
    "class Queue:\n",
    "    def __init__(self, type, sort_by = ''):\n",
    "        self.type = type\n",
    "        self.items = []\n",
    "        self.sort_by = sort_by\n",
    "\n",
    "    def clear(self):\n",
    "        self.items.clear()\n",
    "    \n",
    "    def is_empty(self):\n",
    "        if len(self.items) > 0:\n",
    "            return False\n",
    "        else:\n",
    "            return True\n",
    "\n",
    "    def push(self, element):\n",
    "        self.items.append(element)\n",
    "        '''\n",
    "        queue = [element_0, element_1, ... , element_n] <- element_n+1\n",
    "        '''\n",
    "        if self.type == 'PRIO':\n",
    "            '''\n",
    "            Sorting so lowest cost/ value is at [0]\n",
    "            queue = [element_0 < element_1 < ... < element_n < element_n+1]\n",
    "            '''\n",
    "            if self.sort_by == '':\n",
    "                self.items.sort(key=lambda item: item.value)\n",
    "            elif self.sort_by == 'f':\n",
    "                self.items.sort(key=lambda item: item.f)\n",
    "\n",
    "    def pop(self):\n",
    "        if not self.is_empty():\n",
    "            if self.type == 'LIFO':\n",
    "                ''' LIFO\n",
    "                queue = [element_0, elemente_1, ... , element_n]\n",
    "                                                            -> pop element_n\n",
    "                '''\n",
    "                return self.items.pop()\n",
    "            else:\n",
    "                ''' FIFO & PRIO\n",
    "                queue = [element_0, element_1, ... , element_n]\n",
    "                            -> pop element_0\n",
    "                '''\n",
    "                return self.items.pop(0)\n",
    "        return None"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 16,
   "id": "d3b77c0a",
   "metadata": {
    "ExecuteTime": {
     "end_time": "2025-05-07T21:40:24.044268Z",
     "start_time": "2025-05-07T21:40:24.041113Z"
    }
   },
   "outputs": [],
   "source": [
    "class Field:\n",
    "    def __init__(self, x, y):\n",
    "        self.x = x\n",
    "        self.y = y\n",
    "        self.state = \"free\"  # states: free, obstacale, start, target\n",
    "\n",
    "        self.g = float('inf')\n",
    "        self.h = 0\n",
    "        self.f = float('inf')\n",
    "        self.parent = None\n",
    "\n",
    "    def draw(self, screen):\n",
    "        # state based coloring\n",
    "        color = WHITE\n",
    "        if self.state == \"obstacale\":\n",
    "            color = BLACK\n",
    "        elif self.state == \"start\":\n",
    "            color = BLUE\n",
    "        elif self.state == \"target\":\n",
    "            color = GREEN\n",
    "        elif self.state == \"path\":\n",
    "            color = ORANGE\n",
    "        elif self.state == \"current\":\n",
    "            color = RED\n",
    "        elif self.state == \"visited\":\n",
    "            color = GREY\n",
    "\n",
    "        x_calc = (MARGIN + WIDTH) * self.x + MARGIN\n",
    "        y_calc = (MARGIN + HEIGHT) * (GRID_SIZE - 1 - self.y) + MARGIN  # flipping\n",
    "\n",
    "        pygame.draw.rect(\n",
    "            screen,\n",
    "            color,\n",
    "            [x_calc, y_calc, WIDTH, HEIGHT]\n",
    "        )"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 17,
   "id": "b3d9f04f",
   "metadata": {
    "ExecuteTime": {
     "end_time": "2025-05-07T21:40:24.125218Z",
     "start_time": "2025-05-07T21:40:24.120389Z"
    }
   },
   "outputs": [],
   "source": [
    "class Grid:\n",
    "    def __init__(self, cols, rows):\n",
    "        self.cols = cols  # x\n",
    "        self.rows = rows  # y\n",
    "        self.grid = []\n",
    "\n",
    "        i = 0\n",
    "        while i < cols:  # col = x\n",
    "            col = []\n",
    "            j = 0\n",
    "            while j < rows:  # row = y\n",
    "                col.append(Field(i, j))  # (x,y)\n",
    "                j += 1\n",
    "            self.grid.append(col)\n",
    "            i += 1\n",
    "\n",
    "        self.start = None\n",
    "        self.target = None\n",
    "\n",
    "    def draw(self, screen):\n",
    "        for col in self.grid:\n",
    "            for field in col:\n",
    "                field.draw(screen)\n",
    "\n",
    "    def heuristic(self, field):\n",
    "        return math.sqrt((field.x - self.target[0]) ** 2 + (field.y - self.target[1]) ** 2)\n",
    "\n",
    "    def get_state(self, x, y):\n",
    "        return self.grid[x][y].state\n",
    "\n",
    "    def set_state(self, state, x, y):\n",
    "        if state == \"free\" or state == \"obstacale\" or state == \"start\" or state == \"target\" or state == \"path\" or state == \"current\" or state == \"visited\":\n",
    "            self.grid[x][y].state = state\n",
    "\n",
    "    def set_free(self, x, y):\n",
    "        self.set_state(\"free\", x, y)\n",
    "\n",
    "    def set_obstacle(self, x, y):\n",
    "        self.set_state(\"obstacale\", x, y)\n",
    "    \n",
    "    def set_current(self, x, y):\n",
    "        self.set_state(\"current\", x, y)\n",
    "    \n",
    "    def set_visited(self, x,y):\n",
    "        self.set_state(\"visited\", x, y)\n",
    "\n",
    "    def set_path(self, x, y):\n",
    "        if not (x == self.start[0] and y == self.start[1]) and not (x == self.target[0] and y == self.target[1]):\n",
    "            self.set_state(\"path\", x, y)\n",
    "\n",
    "    def set_start(self, x, y):\n",
    "        # reset old start if it exits\n",
    "        if self.start:\n",
    "            self.set_free(self.start[0], self.start[1])\n",
    "\n",
    "        self.set_state(\"start\", x, y)\n",
    "        self.grid[x][y].parent = self.grid[x][y]\n",
    "        self.grid[x][y].g = 0\n",
    "        self.grid[x][y].h = self.heuristic(self.grid[x][y])\n",
    "        self.grid[x][y].f = self.grid[x][y].h + self.grid[x][y].g\n",
    "        self.start = (x, y)\n",
    "\n",
    "    def set_target(self, x, y):\n",
    "        # reset old target if it exits\n",
    "        if self.target:\n",
    "            self.set_free(self.target[0], self.target[1])\n",
    "\n",
    "        self.set_state(\"target\", x, y)\n",
    "\n",
    "        self.target = (x, y)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "a01bed4a",
   "metadata": {},
   "source": [
    "## Defining Grid Parameters"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 18,
   "id": "53c20ed6",
   "metadata": {
    "ExecuteTime": {
     "end_time": "2025-05-07T21:40:24.289574Z",
     "start_time": "2025-05-07T21:40:24.250017Z"
    }
   },
   "outputs": [],
   "source": [
    "\n",
    "window_width = GRID_SIZE * (WIDTH + MARGIN) + MARGIN\n",
    "window_height = GRID_SIZE * (HEIGHT + MARGIN) + MARGIN\n",
    "size = (window_width, window_height)  # made size variable\n",
    "\n",
    "start = (0, 0)\n",
    "target = (19, 19)\n",
    "grid = Grid(GRID_SIZE, GRID_SIZE)\n",
    "\n",
    "# check if start an target are valid\n",
    "if 0 <= start[0] < grid.cols and 0 <= target[0] < grid.cols and 0 <= start[1] < grid.cols and 0 <= target[\n",
    "    1] < grid.cols:\n",
    "    grid.set_target(target[0], target[1])\n",
    "    grid.set_start(start[0], start[1])\n"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "e67b33e5",
   "metadata": {},
   "source": [
    "### Creating Obsticales"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 19,
   "id": "d01d53b0",
   "metadata": {
    "ExecuteTime": {
     "end_time": "2025-05-07T21:40:24.329858Z",
     "start_time": "2025-05-07T21:40:24.327366Z"
    }
   },
   "outputs": [],
   "source": [
    "for i in range(0, 10):\n",
    "    grid.set_obstacle(9, i)\n",
    "\n",
    "for j in range(4, 10):\n",
    "    grid.set_obstacle(j, 9)\n",
    "\n",
    "for i in range(9, 20):\n",
    "    grid.set_obstacle(16, i)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "334e0e61",
   "metadata": {},
   "source": [
    "## Initialize A* Parameters"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 20,
   "id": "d480bcf1",
   "metadata": {
    "ExecuteTime": {
     "end_time": "2025-05-07T21:40:24.378185Z",
     "start_time": "2025-05-07T21:40:24.374640Z"
    }
   },
   "outputs": [],
   "source": [
    "open = Queue('PRIO', 'f')\n",
    "open.push(grid.grid[0][0])\n",
    "closed = Queue('PRIO', 'f')\n",
    "neighbors = []\n",
    "path = []\n",
    "done = False"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "6898177d",
   "metadata": {},
   "source": [
    "## Initialize PyGame Window"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 21,
   "id": "a8c78a46",
   "metadata": {
    "ExecuteTime": {
     "end_time": "2025-05-07T21:40:25.086317Z",
     "start_time": "2025-05-07T21:40:24.429636Z"
    }
   },
   "outputs": [],
   "source": [
    "pygame.init()\n",
    "screen = pygame.display.set_mode(size)\n",
    "pygame.display.set_caption(\"A* Algorithm\")\n",
    "clock = pygame.time.Clock()\n",
    "\n",
    "def update_screen():\n",
    "    screen.fill(BLACK)\n",
    "    grid.draw(screen)\n",
    "    pygame.display.flip()\n",
    "    clock.tick(60)"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "3939b45f",
   "metadata": {},
   "source": [
    "## A*-Algorithm"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 22,
   "id": "4c138642",
   "metadata": {
    "ExecuteTime": {
     "end_time": "2025-05-07T21:40:49.022562Z",
     "start_time": "2025-05-07T21:40:25.146989Z"
    }
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Gefunden\n"
     ]
    }
   ],
   "source": [
    "while not done:\n",
    "    for event in pygame.event.get():\n",
    "        if event.type == pygame.QUIT:\n",
    "            done = True\n",
    "\n",
    "    while not open.is_empty():\n",
    "        current_field = open.pop()\n",
    "        grid.set_current(current_field.x, current_field.y)\n",
    "                \n",
    "        update_screen()\n",
    "\n",
    "        if current_field.x == grid.target[0] and current_field.y == grid.target[1]:            \n",
    "            path.append(current_field)\n",
    "            grid.set_path(current_field.x, current_field.y)\n",
    "            \n",
    "            while not (current_field.x == grid.start[0] and current_field.y == grid.start[1]):\n",
    "                current_field = current_field.parent\n",
    "                path.insert(0, current_field)\n",
    "                grid.set_path(current_field.x, current_field.y)\n",
    "\n",
    "                update_screen()\n",
    "\n",
    "            open.clear()\n",
    "            # done = True\n",
    "\n",
    "        closed.push(current_field)\n",
    "        grid.set_visited(current_field.x, current_field.y)\n",
    "\n",
    "\n",
    "        for dx, dy in [(0, -1), (-1, 0), (0, 1), (1, 0)]:\n",
    "            nx = current_field.x + dx\n",
    "            ny = current_field.y + dy\n",
    "\n",
    "            if 0 <= nx < grid.cols and 0 <= ny < grid.rows:\n",
    "                neighbor = grid.grid[nx][ny]\n",
    "\n",
    "                if neighbor.state == \"obstacale\" or closed.items.__contains__(neighbor):\n",
    "                    continue\n",
    "\n",
    "                tentative_g = current_field.g + 1\n",
    "\n",
    "                if tentative_g < neighbor.g:\n",
    "                    neighbor.parent = current_field\n",
    "                    neighbor.g = tentative_g\n",
    "                    neighbor.h = grid.heuristic(neighbor)\n",
    "                    neighbor.f = neighbor.g + neighbor.h\n",
    "\n",
    "                    if open.items.__contains__(neighbor):\n",
    "                        open.items.sort(key=lambda item: item.f)\n",
    "                    else:\n",
    "                        open.push(neighbor)\n",
    "\n",
    "        update_screen()\n",
    "    \n",
    "if len(path) == 0:\n",
    "    print(\"No path between\")\n",
    "else:\n",
    "    print(\"Gefunden\")\n",
    "\n",
    "pygame.quit()"
   ]
  }
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