#include "ghosts.h"
#include "field.h"
#include "pac.h"
#include "queue.h"
#include <ncurses.h>
#include <math.h>
#include <stdlib.h>

enum search_flag { viewed, not_viewed };

void initialize_ghost(struct ghost_type *ghost, enum ghost_color color)
{
    switch(color) {
    case red:
        ghost->position.y = red_y;
        ghost->position.x = red_x;
        ghost->home_position.y = red_home_y;
        ghost->home_position.x = red_home_x;
        ghost->color = red;
        ghost->mode = scatter;
        ghost->direction = none;
        break;
    case pink:
        ghost->position.y = pink_y;
        ghost->position.x = pink_x;
        ghost->home_position.y = pink_home_y;
        ghost->home_position.x = pink_home_x;
        ghost->color = pink;
        ghost->mode = scatter;
        ghost->direction = none;
        break;
    case blue:
        ghost->position.y = blue_y;
        ghost->position.x = blue_x;
        ghost->home_position.y = blue_home_y;
        ghost->home_position.x = blue_home_x;
        ghost->color = blue;
        ghost->mode = scatter;
        ghost->direction = none;
        break;
    case orange:
        ghost->position.y = orange_y;
        ghost->position.x = orange_x;
        ghost->home_position.y = orange_home_y;
        ghost->home_position.x = orange_home_x;
        ghost->color = orange;
        ghost->mode = scatter;
        ghost->direction = none;
        break;
    }
}

void pull_out_ghosts(int *get_out_stage,
                     struct ghost_type *red_ghost,
                     struct ghost_type *pink_ghost,
                     struct ghost_type *blue_ghost,
                     struct ghost_type *orange_ghost)
{
    enum { final_stage = 1 };
    enum movement_direction red_moves[] = { none, right, up, up, left };
    enum movement_direction blue_moves[] = { none, left, up, up, left };
    enum movement_direction pink_moves[] = { right, up, up, up, right };
    enum movement_direction orange_moves[] = { left, up, up, up, right };
    int index = *get_out_stage - 1;
    if(*get_out_stage > final_stage) {
        red_ghost->direction = red_moves[index];
        blue_ghost->direction = blue_moves[index];
    }
    pink_ghost->direction = pink_moves[index];
    orange_ghost->direction = orange_moves[index];
    --*get_out_stage;
}

static void change_position(struct ghost_type *ghost,
                            enum movement_direction direction)
{
    switch(direction) {
    case left:
        --ghost->position.x;
        return;
    case right:
        ++ghost->position.x;
        return;
    case up:
        --ghost->position.y;
        return;
    case down:
        ++ghost->position.y;
        return;
    default:
        return;
    }
}

void make_ghost_moves(game_space field,
                      struct ghost_type *red_ghost,
                      struct ghost_type *pink_ghost,
                      struct ghost_type *blue_ghost,
                      struct ghost_type *orange_ghost,
                      struct queue *eaten_coins)
{
    clear_or_revert_symbol(field, red_ghost->position, ghost_char, eaten_coins);
    clear_or_revert_symbol(field, pink_ghost->position, ghost_char,
                           eaten_coins);
    clear_or_revert_symbol(field, blue_ghost->position, ghost_char,
                           eaten_coins);
    clear_or_revert_symbol(field, orange_ghost->position, ghost_char,
                           eaten_coins);
    change_position(red_ghost, red_ghost->direction);
    change_position(pink_ghost, pink_ghost->direction);
    change_position(blue_ghost, blue_ghost->direction);
    change_position(orange_ghost, orange_ghost->direction);
}

static void pave_only_way(game_space field, struct ghost_type *ghost)
{
    struct free_directions path = find_free_directions(field, ghost->position.y,
                                                       ghost->position.x);
    enum movement_direction reverse_direction = ghost->direction;
    reverse_direction ^= 1;
    if(path.left && left != reverse_direction)
        ghost->direction = left;
    else if(path.right && right != reverse_direction)
        ghost->direction = right;
    else if(path.up && up != reverse_direction)
        ghost->direction = up;
    else if(path.down && down != reverse_direction)
        ghost->direction = down;
}

struct coordinates identify_blue_target(struct pacman pac,
                                        const struct ghost_type *red_ghost)
{
    struct coordinates difference, middle_point, result_point;
    middle_point = identify_target_in_front(pac, blue_shift);
    difference.x = middle_point.x - red_ghost->position.x;
    difference.y = middle_point.y - red_ghost->position.y;
    result_point.x = middle_point.x + difference.x;
    result_point.y = middle_point.y + difference.y;
    return result_point;
}

struct coordinates identify_target_in_front(struct pacman pac, int shift)
{
    int x, y;
    struct coordinates target;
    x = pac.position.x;
    y = pac.position.y;
    switch(pac.direction) {
    case left:
        x -= shift;
        break;
    case right:
        x += shift;
        break;
    case up:
        y -= shift;
        break;
    case down:
        y += shift;
        break;
    default:
        ;
    }
    target.x = x;
    target.y = y;
    return target;
}

void redirect(game_space field, enum intersection_type paths,
              struct ghost_type *ghost, struct coordinates target_point,
              void (*pathfinder)(game_space, struct ghost_type*,
                    struct coordinates target_point))
{
    if(paths == one_path)
        pave_only_way(field, ghost);
    else
        pathfinder(field, ghost, target_point);
}

static struct coordinates get_near_point(struct coordinates consider_point,
                                         int dx, int dy)
{
    struct coordinates found_point;
    found_point.x = consider_point.x + dx;
    found_point.y = consider_point.y + dy;
    return found_point;
}

static enum movement_direction find_direction(struct coordinates found_point,
                                              struct coordinates ghost_position)
{
    int dx, dy;
    enum movement_direction new_direction;
    dx = found_point.x - ghost_position.x;
    dy = found_point.y - ghost_position.y;
    switch(dx) {
    case 1:
        new_direction = dy == 0 ? right : none;
        break;
    case 0:
        new_direction = dy == -1 ? up : down;
        break;
    case -1:
        new_direction = dy == 0 ? left : none;
        break;
    }
    return new_direction;
}

static void clear_both_queues(struct queue *next_points,
                              struct queue *reviewed_points)
{
    queue_clear(next_points);
    queue_clear(reviewed_points);
}

static int is_bfs_search_for_orange(enum search_flag current_width,
                                    int move_count)
{
    if(current_width == not_viewed)
        ++move_count;
    return move_count > orange_search_limit;
}

void breadth_first_search(game_space field, struct ghost_type *ghost,
                          struct coordinates target_point)
{
    int move_count;
    enum search_flag current_width = not_viewed;
    struct coordinates consider_point, near_point;
    struct coordinates start_point = { ghost->position.y, ghost->position.x };
    struct queue next_points, reviewed_points;
    move_count = 0;
    queue_init(&next_points);
    queue_init(&reviewed_points);
    queue_push(&next_points, &target_point);
    queue_push(&reviewed_points, &target_point);
    while(!empty(&next_points)) {
        consider_point = queue_front(&next_points);
        pop(&next_points);
        int dx;
        for(dx = -1; dx <= 1; ++dx) {
            int dy;
            for(dy = -1; dy <= 1; ++dy) {
                if(dx != 0 && dy != 0)
                    continue;
                near_point = get_near_point(consider_point, dx, dy);
                if(is_obstacle(field, near_point.x, near_point.y))
                    continue;
                if(queue_consists_point(&reviewed_points, near_point))
                    continue;
                if(equal_points(start_point, near_point)) {
                    if(ghost->color == orange)
                        if(!is_bfs_search_for_orange(current_width,
                                                     move_count)) {
                            redirect(field, two_paths, ghost,
                                     ghost->home_position,
                                     compute_distance_between_points);
                            clear_both_queues(&next_points, &reviewed_points);
                            return;
                        }
                    ghost->direction =
                        find_direction(consider_point, start_point);
                    clear_both_queues(&next_points, &reviewed_points);
                    return;
                }
                if(ghost->color == orange && current_width == not_viewed) {
                    current_width = viewed;
                    ++move_count;
                }
                queue_push(&next_points, &near_point);
                queue_push(&reviewed_points, &near_point);
            }
        }
        current_width = not_viewed;
    }
}

static int standard_distance(int x1, int y1, int x2, int y2)
{
    int dx, dy;
    dx = abs(x1 - x2);
    dx = dx > field_width ? field_width - dx : dx;
    dy = abs(y1 - y2);
    return sqrt(dx*dx + dy*dy);
 }

static int is_minimal_distance(int min_distance, int tmp_distance,
                               enum movement_direction cur_direction)
{
    return min_distance == 0 || tmp_distance < min_distance ||
           (tmp_distance == min_distance && cur_direction != right);
}

static void set_final_direction(int *min_distance,
                                enum movement_direction cur_direction,
                                enum movement_direction *final_direction,
                                struct coordinates initial_point,
                                struct coordinates target_point)
{
    int x1, y1, x2, y2;
    int tmp_distance;
    x1 = initial_point.x;
    y1 = initial_point.y;
    x2 = target_point.x;
    y2 = target_point.y;
    tmp_distance = standard_distance(x1, y1, x2, y2);
    if(is_minimal_distance(*min_distance, tmp_distance, cur_direction)) {
        *min_distance = tmp_distance;
        *final_direction = cur_direction;
    }
}

void compute_distance_between_points(game_space field,
                                     struct ghost_type *ghost,
                                     struct coordinates target_point)
{
    enum movement_direction final_direction, ghost_direction;
    struct coordinates initial_point, changed_initial_point;
    int min_distance;
    final_direction = none;
    ghost_direction = ghost->direction;
    initial_point = ghost->position;
    min_distance = 0;
    struct free_directions consider_paths =
        find_free_directions(field, initial_point.y, initial_point.x);
    if(consider_paths.right && ghost_direction != left) {
        changed_initial_point.x = initial_point.x + 1;
        changed_initial_point.y = initial_point.y;
        set_final_direction(&min_distance, right, &final_direction,
                            changed_initial_point, target_point);
    }
    if(consider_paths.down && ghost_direction != up) {
        changed_initial_point.x = initial_point.x;
        changed_initial_point.y = initial_point.y + 1;
        set_final_direction(&min_distance, down, &final_direction,
                            changed_initial_point, target_point);
    }
    if(consider_paths.left && ghost_direction != right) {
        changed_initial_point.x = initial_point.x - 1;
        changed_initial_point.y = initial_point.y;
        set_final_direction(&min_distance, left, &final_direction,
                            changed_initial_point, target_point);
    }
    if(consider_paths.up && ghost_direction != down) {
        changed_initial_point.x = initial_point.x;
        changed_initial_point.y = initial_point.y - 1;
        set_final_direction(&min_distance, up, &final_direction,
                            changed_initial_point, target_point);
    }
    ghost->direction = final_direction;
}