#include "Dijkstra.h"


void Dijkstra::MazeSearch(char** maze, uint32_t mazeHeight, uint32_t mazeWidth, PathGenerator::Location startpoint, uint32_t exit_y, uint32_t exit_x) {
    std::vector<distance> distances;
    uint32_t distance_cnt = 3u;
    distances.push_back({ startpoint.row, startpoint.col});
    bool new_distance = true;
    uint32_t y = 0u;
    uint32_t x = 0u;

    /* Walk away from the entrace and save distance (from entrance). */
    while (new_distance) {
        new_distance = false;
        uint32_t distance_max = distances.size();
        distance_cnt++;
        /* With the for loop, we can walk "parellel". */
        for (uint32_t i = 0u; i < distance_max; i++) {
            y = distances[0u].y;
            x = distances[0u].x;

            maze[y][x] = distance_cnt;
            /* north is valid, save. */
            if ((y > 0u) && (Maze_Char_Space == maze[y - 1u][x])) {
                distances.push_back({ y - 1u,x });
                new_distance = true;
            }
            /* south is valid, save. */
            if (((y + 1u) < (mazeHeight)) && (Maze_Char_Space == maze[y + 1u][x])) {
                distances.push_back({ y + 1u,x });
                new_distance = true;
            }
            /* west is valid, save. */
            if ((x > 0u) && (Maze_Char_Space == maze[y][x - 1u])) {
                distances.push_back({ y,x - 1u });
                new_distance = true;
            }
            /*  east is valid, save. */
            if (((x + 1u) < mazeWidth) && (Maze_Char_Space == maze[y][x + 1u])) {
                distances.push_back({ y,x + 1u });
                new_distance = true;
            }
            /* Stop at the end. */
            if ((y == exit_y) && (x == exit_x)) {
                new_distance = false;
                break;
            }
            distances.erase(distances.begin());
        }
    }

    /* Walk back from the exit to the entrance. */
    y = exit_y;
    x = exit_x;
    distance_cnt = maze[y][x];

    /* Loop until we aren't at the beginning. */
    while (3u != distance_cnt) {
        /* Mark everything as a solution on the way. */
        maze[y][x] = Maze_Char_Path;
        distance_cnt--;
        if ((y > 0u) && (distance_cnt == maze[y - 1u][x])) {
            y--;
        }
        else if (((y + 1u) < mazeHeight) && (distance_cnt == maze[y + 1u][x])) {
            y++;
        }
        else if ((x > 0u) && (distance_cnt == maze[y][x - 1u])) {
            x--;
        }
        else if (((x + 1u) < mazeWidth) && (distance_cnt == maze[y][x + 1u])) {
            x++;
        }
        else {
            /* Do nothing. */
        }
    }

    for (uint32_t y = 0u; y < mazeHeight; y++) {
        for (uint32_t x = 0u; x < mazeWidth; x++) {
            if ((Maze_Char_Wall != maze[y][x]) && (Maze_Char_Path != maze[y][x])) {
                maze[y][x] = Maze_Char_Space;
            }
        }
    }
}