#include <algolib.c>
#include <math.h>
#include <stdbool.h>
#include <stdio.h>
#include <vectorlib.c>

#include <SDL2/SDL.h>
#include <SDL2/SDL2_gfxPrimitives.h>
#include <SDL2/SDL_render.h>
#include <SDL2/SDL_ttf.h>
#include <SDL2/SDL_video.h>

#define PROJECT_NAME "algorithms-maze 1"

#define grid_cols 10
#define grid_rows grid_cols

#define obj_n grid_cols* grid_rows

#define frame_delay 10

typedef struct {
    int i;
    int j;
    //top, right, bottom, left
    bool walls[4];
    bool visited;
} CELL;

typedef struct OBJECT {
    CELL items[obj_n];
    CELL* current;
    CELL* stack[obj_n];
    int w;
    int h;
} OBJECT;

#include <init.h>

int get_index(int i, int j){ 
    if (i < 0 || j < 0 || i > grid_cols-1 || j > grid_rows-1)
        return -1;
    return (j * grid_cols + i);
}

void cell_constructor(CELL* cell,int i,int j){
    cell->i = i;
    cell->j = j;
    for (int i=0; i<4; i++){
        cell->walls[i]=true;
    }
    cell->visited=false;
}

void push_cell(CELL* arr[], CELL* cell, int count){
    for (int i=0; i<count; i++){
        if(!arr[i]){
            arr[i]=cell;
            return;
        }
    }
}

CELL* pop_cell(CELL* arr[], int count){
    CELL* ret_cell;
    for (int i=0; i<count; i++){
        if(!arr[i]){
            ret_cell = arr[i-1];
            arr[i-1]=NULL;
            return ret_cell;
        } else if (i == count){
            ret_cell = arr[i];
            arr[i]=NULL;
            return ret_cell;
        }
    }
    return NULL;
}

CELL* cell_checkNeighbors(CELL* cell, STUFFS* stuff){
    CELL* neighbors[4];
    for (int i=0; i<4; i++) { neighbors[i] = NULL; }

    CELL *top = NULL;
    CELL *right = NULL;
    CELL *bottom = NULL;
    CELL *left = NULL;

    int index=get_index(cell->i,cell->j-1);
    if(index != -1)
        top = &stuff->obj.items[index];
    index = get_index(cell->i+1,cell->j);
    if(index != -1)
        right = &stuff->obj.items[index];
    index = get_index(cell->i,cell->j+1);
    if(index != -1)
        bottom = &stuff->obj.items[index];
    index = get_index(cell->i-1,cell->j);
    if(index != -1)
        left = &stuff->obj.items[index];

    if (top && !top->visited) {
        push_cell(neighbors,top,4);
    }
    if (right && !right->visited) {
        push_cell(neighbors,right,4);
    }
    if (bottom && !bottom->visited) {
        push_cell(neighbors,bottom,4);
    }
    if (left && !left->visited) {
        push_cell(neighbors,left,4);
    }

    int neighbors_len=0;    
    for (int i=0; i<4; i++){
        if(neighbors[neighbors_len]) {
            neighbors_len++;
        } else {
            break;
        }
    }

    if(neighbors_len > 0) {
        int r = (int)RandomFloat(0,neighbors_len);
        return neighbors[r];
    } else {
        return NULL;
    }
}

void cell_removeWalls(CELL* a, CELL* b){
    int x = a->i - b->i;
    if (x == 1){
        a->walls[3] = false;
        b->walls[1] = false;
    } else if (x == -1){
        a->walls[1] = false;
        b->walls[3] = false;
    }
    int y = a->j - b->j;
    if (y == 1){
        a->walls[0] = false;
        b->walls[2] = false;
    } else if (y == -1){
        a->walls[2] = false;
        b->walls[0] = false;
    }
}

void init_stuffs(int w, int h, STUFFS* stuff)
{
    stuff->obj.w = stuff->width / grid_cols;
    stuff->obj.h = stuff->height / grid_rows;

    for (int j = 0; j < grid_rows; j++) {
        for (int i = 0; i < grid_cols; i++) {
            int index = j * grid_cols + i;
            cell_constructor(&stuff->obj.items[index],i,j);
            stuff->obj.stack[index] = NULL;
        }
    }

    stuff->obj.current = &stuff->obj.items[0];
}

void draw_cell(CELL* cell, STUFFS* stuff)
{
    int w = stuff->obj.w;
    int x = cell->i * w;
    int y = cell->j * w;
    //SDL_RenderDrawRect(stuff->renderer, &(SDL_Rect) { x, y, w, w });
    SDL_SetRenderDrawColor(stuff->renderer, 255, 255, 255, 255);
    if (cell->walls[0]==true)
        SDL_RenderDrawLine(stuff->renderer,x,y,x+w,y);
    if (cell->walls[1]==true)
        SDL_RenderDrawLine(stuff->renderer,x+w,y,x+w,y+w);
    if (cell->walls[2]==true)
        SDL_RenderDrawLine(stuff->renderer,x+w,y+w,x,y+w);
    if (cell->walls[3]==true)
        SDL_RenderDrawLine(stuff->renderer,x,y+w,x,y);

    if (cell->visited==true){
        SDL_SetRenderDrawColor(stuff->renderer, 255, 0, 255, 100);
        SDL_RenderFillRect(stuff->renderer, &(SDL_Rect) { x, y, w, w });
    }
}

void draw_highlight(CELL* cell, STUFFS* stuff){
    int w = stuff->obj.w;
    int x = cell->i * w;
    int y = cell->j * w;
    SDL_SetRenderDrawColor(stuff->renderer, 0, 0, 255, 100);
    SDL_RenderFillRect(stuff->renderer, &(SDL_Rect) { x, y, w, w });
}

float dist(float x, float y, float x2, float y2)
{
    return sqrt((pow(x, 2) + pow(y, 2) + pow(x2, 2) + pow(y2, 2)));
}

void draw(SDL_Window* window, STUFFS* stuff)
{
    static bool done = false;
    if (done == false) {
        SDL_SetRenderDrawColor(stuff->renderer, 20, 20, 20, 255);
        // SDL_RenderClear(renderer);
        SDL_RenderFillRect(stuff->renderer, &(SDL_Rect) { 0, 0, stuff->width, stuff->height });

        for (int i=0; i<obj_n; i++){
            draw_cell(&stuff->obj.items[i],stuff);
        }

        int stack_len=0;    
        for (int i=0; i<obj_n; i++){
            if(stuff->obj.stack[stack_len]) {
                stack_len++;
            } else {
                break;
            }
        }

        // STEP 1
        stuff->obj.current->visited=true;
        draw_highlight(stuff->obj.current,stuff);
        CELL* next = cell_checkNeighbors(stuff->obj.current, stuff);
        if (next != NULL){
            next->visited=true;
            // STEP 2
            push_cell(stuff->obj.stack,stuff->obj.current,obj_n);

            // STEP 3
            cell_removeWalls(stuff->obj.current, next);

            // STEP 4
            stuff->obj.current = next;
        } else if (stack_len > 0) {
            stuff->obj.current = pop_cell(stuff->obj.stack,obj_n);
        }

        SDL_RenderPresent(stuff->renderer);
    }
}

void on_end(STUFFS* stuff)
{
}

#include <init.c>

/* Challanges
 *
 * highlighting the cells in the stack a different color
 * 
 */