#include <stdint.h>

#include "keyb.h"
#include "vga.h"
#include "map.h"
#include "data.h"
#include "game.h"

#include "entities.h"
#include "player.h"

#define FRAME_STANDING 0
#define FRAME_JUMPING 4
#define FRAME_DYING 5

#define WALK_CYCLE_FRAMES 4

#define GRAVITY_OFF 0
/* XXX: subtract 1 to get the value from gravity_seq */
#define GRAVITY_DOWN 14
#define GRAVITY_UP 1

#define GRAVITY_SEQ_LEN 24

/* used for "coyote time" */
#define MAX_MOMENTUM 8

/* how many frames the player is invulerable after loosing a life */
#define INVULN_TIME 96

#define IS_NOT_GOING_UP(x) (gravity == GRAVITY_OFF || (x)>=GRAVITY_DOWN)

static uint16_t x, y;
static uint8_t dir, frame, delay, gravity, jump, momentum;

static uint16_t respawn_x, respawn_y;
static uint8_t respawn_dir;

static uint8_t invuln, dying;

const uint8_t gravity_seq[GRAVITY_SEQ_LEN] = {
    6, 4, 4, 2, 2, 2, 2, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 2, 2, 2, 2, 4
};

static uint8_t bg[256];

static const Rect frames[2][6] =
{
    {
        /* walk cycle */
        { 0, 0, 144, 144 },
        { 16, 0, 144, 144 },
        { 0, 0, 144, 144 },
        { 32, 0, 144, 144 },

        /* jump */
        { 48, 0, 144, 144 },

        /* dying */
        { 128, 0, 144, 144 },
    },
    {
        /* walk cycle */
        { 64, 0, 144, 144 },
        { 80, 0, 144, 144 },
        { 64, 0, 144, 144 },
        { 96, 0, 144, 144 },

        /* jump */
        { 112, 0, 144, 144 },

        /* dying */
        { 128, 0, 144, 144 },
    },
};

void player_init(uint16_t start_x, uint8_t start_y, uint8_t start_dir)
{
    respawn_dir = dir = start_dir;
    frame = FRAME_STANDING;
    delay = 0;
    jump = 0;
    momentum = 0;
    invuln = 0;
    dying = 0;

    respawn_x = x = start_x;
    respawn_y = y = start_y;
    gravity = GRAVITY_OFF;
}

static void player_dying()
{
    if (gravity != GRAVITY_OFF)
    {
        uint8_t steps = gravity_seq[gravity - 1];

        if (gravity > GRAVITY_DOWN)
        {
            /* going down! */
            for (uint8_t i = 0; i < steps; i++)
            {
                /* exit screen */
                if (y > MAP_H * MAP_TILE_H)
                {
                    /* if there are lifes left, respawn */
                    if (dec_lives())
                    {
                        player_init(respawn_x, respawn_y, respawn_dir);
                        invuln = INVULN_TIME;
                    }

                    /* stop falling */
                    gravity = GRAVITY_OFF;
                    return;
                }
                y++;
            }
        }
        else
        {
            /* going up! */
            if (y < steps)
                y = 0;
            else
                y -= steps;
        }

        if (gravity != GRAVITY_OFF && gravity != GRAVITY_SEQ_LEN)
            gravity++;
    }
}

void player_update()
{
    uint8_t moved = 0;

    if (dying)
    {
        player_dying();
        return;
    }

    if (invuln)
        invuln--;

    if (momentum)
        momentum--;

    if (gravity == GRAVITY_OFF
            && !map_is_blocked(x + 4, y + 16)
            && !map_is_blocked(x + 11, y + 16))
    {
        gravity = GRAVITY_DOWN;
        frame = FRAME_JUMPING;
        moved = 1;
    }

    if (keys[KEY_UP])
    {
        if ((gravity == GRAVITY_OFF || momentum) && !jump)
        {
            jump = 1;
            momentum = 0;
            frame = FRAME_JUMPING;
            gravity = GRAVITY_UP;
        }
    }
    else
        jump = 0;

    if (keys[KEY_RIGHT] && !keys[KEY_LEFT])
    {
        moved = 1;
        dir = DIR_RIGHT;

        /* XXX: off limits */
        if (x < MAP_W * MAP_TILE_W - 16)
        {
            if ((IS_NOT_GOING_UP(gravity) && !map_is_blocked(x + 16, y + 15))
                    || (!IS_NOT_GOING_UP(gravity)
                        && !(map_is_blocked(x + 16, y + 15)
                             && map_is_blocked(x + 16, y + 7))))
            {
                if (gravity == GRAVITY_OFF && momentum < MAX_MOMENTUM)
                    momentum += 4;
                x++;
            }
        }
    }

    if (keys[KEY_LEFT] && !keys[KEY_RIGHT])
    {
        moved = 1;
        dir = DIR_LEFT;

        /* XXX: off limits */
        if (x)
        {
            if ((IS_NOT_GOING_UP(gravity) && !map_is_blocked(x - 1, y + 15))
                    || (!IS_NOT_GOING_UP(gravity)
                        && !(map_is_blocked(x - 1, y + 15)
                             && map_is_blocked(x - 1, y + 7))))
            {
                if (gravity == GRAVITY_OFF && momentum < MAX_MOMENTUM)
                    momentum += 4;
                x--;
            }
        }
    }

    if (gravity != GRAVITY_OFF)
    {
        uint8_t steps = gravity_seq[gravity - 1];

        moved = 1;

        if (gravity > GRAVITY_DOWN)
        {
            /* going down! */
            for (uint8_t i = 0; i < steps; i++)
            {
                /* hit the floor */
                if ((map_is_blocked(x + 11, y + 16)
                        || map_is_blocked(x + 4, y + 16))
                        && !map_is_blocked(x + 4, y + 15)
                        && !map_is_blocked(x + 11, y + 15))
                {
                    gravity = GRAVITY_OFF;
                    frame = FRAME_STANDING;

                    /* is a deadly block? */
                    if (map_is_deadly(x + 11, y + 16)
                            || map_is_deadly(x + 4, y + 16))
                    {
                        player_hit();
                        return;
                    }
                    break;
                }
                y++;
            }
        }
        else
        {
            /* going up! */
            if (y < steps)
                y = 0;
            else
                y -= steps;
        }

        if (gravity != GRAVITY_OFF && gravity != GRAVITY_SEQ_LEN)
            gravity++;
    }

    if (moved)
    {
        if (delay++ == WALK_DELAY)
        {
            delay = 0;
            if (frame != FRAME_JUMPING)
            {
                frame++;
                if (frame == WALK_CYCLE_FRAMES)
                    frame = FRAME_STANDING;
            }
        }
    }
    else
    {
        delay = 0;
        frame = FRAME_STANDING;
    }

    if (map_update_gold(x + (dir == DIR_LEFT ? 7 : 8), y + 15))
        add_score(10);
}

void player_erase()
{
    Rect dst = { x, y + MAP_OFFS_Y, 16, 16 };
    blit(bg, &dst);
}

void player_draw()
{
    Rect dst = { x, y + MAP_OFFS_Y, 16, 16 };

    read_buffer(bg, &dst);

    if (invuln && (invuln & 4))
        return;

    blitrc(binary_sprites_start, &frames[dir][frame], &dst);
}

uint8_t player_collision(Entity *e)
{
    if (invuln || dying)
        return 0;

    if (y < e->y + 16 && e->y < y + 16
            && x < e->x + 8 && e->x < x + 8)
        return 1;

    return 0;
}

void player_hit()
{
    /* TODO: pickaxe */
    dying = 1;
    frame = FRAME_DYING;
    gravity = GRAVITY_UP;
}