#include "comp/entity.h"
#include "comp/physical.h"
#include "comp/visible.h"
#include "comp/mechanical.h"
#include "comp/fighter.h"
#include "aoe.h"
#include "enemies.h"
#include "skills.h"
#include <gint/defs/util.h>
#include <string.h>

/* Declare animations for an enemy */
#define ANIMS(name, I, W, A, H, D) \
    .anim_idle =    &anims_ ## name ## _ ## I, \
    .anim_walking = &anims_ ## name ## _ ## W, \
    .anim_attack =  &anims_ ## name ## _ ## A, \
    .anim_hit =     &anims_ ## name ## _ ## H, \
    .anim_death =   &anims_ ## name ## _ ## D

struct bat_ai {
    fixed_t retreat_period;
};

static enemy_t const slime_1 = {
    .name = "Slime",
    .level = 1,
    ANIMS(slime, Idle, Walking, Attack, Hit, Death),
    .hitbox = (rect){ -fix(3)/16, fix(4)/16, -fix(2)/16, fix(3)/16 },
    .limits = {
        .max_speed = fix(1),
        .friction = fix(0.6),
        .max_disruption_speed = fix(999.0),
    },
    .stats_base   = { .HP=10, .ATK=8, .MAG=5, .DEF=5 },
    .stats_growth = { .HP=8,  .ATK=4, .MAG=4, .DEF=2 },

    .shadow_size = 4,
    .xp = 2,
    .z = 0,
    .ai_data_size = 0,
};

static enemy_t const bat_2 = {
    .name = "Bat",
    .level = 2,
    ANIMS(bat, Idle, Idle, Idle, Hit, Death),
    .hitbox = (rect){ -fix(3)/16, fix(4)/16, -fix(2)/16, fix(3)/16 },
    .limits = {
        .max_speed = fix(1.8),
        .friction = fix(0.8),
        .max_disruption_speed = fix(999.0),
    },
    .stats_base   = { .HP=12, .ATK=10, .MAG=5, .DEF=5 },
    .stats_growth = { .HP=10, .ATK=3,  .MAG=2, .DEF=1 },

    .shadow_size = 4,
    .xp = 8,
    .z = fix(0.75),
    .ai_data_size = sizeof(struct bat_ai),
};

static enemy_t const fire_slime_4 = {
    .name = "Fire slime",
    .level = 4,
    ANIMS(fire_slime, Idle, Walking, Attack, Hit, Death),
    .hitbox = (rect){ -fix(3)/16, fix(4)/16, -fix(2)/16, fix(3)/16 },
    .limits = {
        .max_speed = fix(1),
        .friction = fix(0.6),
        .max_disruption_speed = fix(999.0),
    },
    /* Same as slime/1 */
    .stats_base   = { .HP=10, .ATK=8, .MAG=5, .DEF=5 },
    .stats_growth = { .HP=8,  .ATK=4, .MAG=4, .DEF=2 },

    .shadow_size = 4,
    .xp = 22,
    .z = 0,
    .ai_data_size = 0,
};

static enemy_t const albinos_bat_6 = {
    .name = "Albinos bat",
    .level = 6,
    ANIMS(albinos_bat, Idle, Idle, Idle, Hit, Death),
    .hitbox = (rect){ -fix(3)/16, fix(4)/16, -fix(2)/16, fix(3)/16 },
    .limits = {
        .max_speed = fix(2.4),
        .friction = fix(0.7),
        .max_disruption_speed = fix(999.0),
    },
    /* Same as bat/2 */
    .stats_base   = { .HP=12, .ATK=10, .MAG=5, .DEF=5 },
    .stats_growth = { .HP=10, .ATK=3,  .MAG=2, .DEF=1 },

    .shadow_size = 4,
    .xp = 40,
    .z = fix(0.5),
    .ai_data_size = sizeof(struct bat_ai),
};

static enemy_t const gunslinger_8 = {
    .name = "Gunslinger",
    .level = 8,
    ANIMS(gunslinger, Idle, Walking, Fire, Hit, Death),
    .hitbox = (rect){ -fix(3)/16, fix(4)/16, -fix(2)/16, fix(3)/16 },
    .limits = {
        .max_speed = fix(1.8),
        .friction = fix(0.8),
        .max_disruption_speed = fix(999.0),
    },
    .stats_base   = { .HP=16, .ATK=12, .MAG=3, .DEF=6 },
    .stats_growth = { .HP=12, .ATK=4,  .MAG=1, .DEF=1 },

    .shadow_size = 4,
    .xp = 60,
    .z = fix(0.25),
    .ai_data_size = 0,
};

static enemy_t const water_slime_8 = {
    .name = "Water slime",
    .level = 8,
    ANIMS(water_slime, Idle, Walking, Attack, Hit, Death),
    .hitbox = (rect){ -fix(3)/16, fix(4)/16, -fix(2)/16, fix(3)/16 },
    .limits = {
        .max_speed = fix(1.2),
        .friction = fix(0.4),
        .max_disruption_speed = fix(999.0),
    },
    /* Same as slime/1 */
    .stats_base   = { .HP=10, .ATK=8, .MAG=5, .DEF=5 },
    .stats_growth = { .HP=8,  .ATK=4, .MAG=4, .DEF=2 },

    .shadow_size = 4,
    .xp = 32,
    .z = 0,
    .ai_data_size = 0,
};

static enemy_t const chemical_slime_10 = {
    .name = "Chemical slime",
    .level = 10,
    ANIMS(chemical_slime, Idle, Walking, Attack, Hit, Death),
    .hitbox = (rect){ -fix(3)/16, fix(4)/16, -fix(2)/16, fix(3)/16 },
    .limits = {
        .max_speed = fix(0.6),
        .friction = fix(0.8),
        .max_disruption_speed = fix(999.0),
    },
    /* Like as slime/1 but boosted MAG over ATK */
    .stats_base   = { .HP=10, .ATK=8, .MAG=5, .DEF=5 },
    .stats_growth = { .HP=8,  .ATK=2, .MAG=6, .DEF=2 },

    .shadow_size = 4,
    .xp = 71,
    .z = 0,
    .ai_data_size = 0,
};

static enemy_t const * const enemies[] = {
    [ENEMY_SLIME_1]             = &slime_1,
    [ENEMY_BAT_2]               = &bat_2,
    [ENEMY_FIRE_SLIME_4]        = &fire_slime_4,
    [ENEMY_ALBINOS_BAT_6]       = &albinos_bat_6,
    [ENEMY_GUNSLINGER_8]        = &gunslinger_8,
    [ENEMY_WATER_SLIME_8]       = &water_slime_8,
    [ENEMY_CHEMICAL_SLIME_10]   = &chemical_slime_10,
};

enemy_t const *enemy_data(int enemy_id)
{
    if(enemy_id < 1 || (size_t)enemy_id >= sizeof enemies / sizeof *enemies)
        return NULL;

    return enemies[enemy_id];
}

entity_t *enemy_make(int enemy_id)
{
    if(enemy_id < 0 || (size_t)enemy_id >= sizeof enemies / sizeof *enemies)
        return NULL;

    entity_t *e = entity_make(physical, visible, mechanical, fighter);
    if(e == NULL)
        return NULL;

    enemy_t const *data = enemies[enemy_id];

    /* These will probably be overridden by the caller */

    physical_t *p = getcomp(e, physical);
    p->x = fix(0);
    p->y = fix(0);
    p->hitbox = data->hitbox;
    p->facing = LEFT;

    visible_t *v = getcomp(e, visible);
    v->z = data->z;
    v->sprite_plane = VERTICAL;
    v->shadow_size = data->shadow_size;
    visible_set_anim(e, data->anim_idle, 1);

    mechanical_t *m = getcomp(e, mechanical);
    m->limits = &data->limits;
    m->vx = fix(0);
    m->vy = fix(0);
    m->dash = fix(0);
    m->dash_facing = 0xff;

    /* Instantiate fighter statistics */
    fighter_t *f = getcomp(e, fighter);
    memset(f, 0, sizeof *f);

    fighter_stats_t stats = fighter_stats_instantiate(&data->stats_base,
        &data->stats_growth, data->level);
    fighter_set_stats(f, &stats);
    f->HP = f->HP_max;
    f->combo_length = 1;
    f->enemy = malloc(sizeof *f->enemy + data->ai_data_size);
    f->enemy->id = data;
    f->enemy->pathfind_dir = (vec2){ 0, 0 };
    f->enemy->pathfind_cycles = 0;
    f->enemy->ai_data = (void *)f->enemy + sizeof *f->enemy;

    /* Specify skills and initialize AI data */
    if(enemy_id == ENEMY_BAT_2 || enemy_id == ENEMY_ALBINOS_BAT_6) {
        struct bat_ai *ai_data = f->enemy->ai_data;
        ai_data->retreat_period = 0;
        if(enemy_id == ENEMY_ALBINOS_BAT_6) {
            f->skills[1] = SKILL_SPEED;
        }
    }
    else if(enemy_id == ENEMY_FIRE_SLIME_4) {
        f->skills[1] = AOE_FIRE_CHARGE;
    }
    else if(enemy_id == ENEMY_GUNSLINGER_8) {
        f->skills[0] = AOE_PROJECTILE;
    }
    else if(enemy_id == ENEMY_WATER_SLIME_8) {
        f->skills[1] = AOE_WATER_CHARGE;
    }
    else if(enemy_id == ENEMY_CHEMICAL_SLIME_10) {
        f->skills[1] = AOE_CHEMICAL_CHARGE;
    }

    return e;
}

/* Enemy AIs */

static void move_towards_player(game_t *g, entity_t *e, fixed_t dt)
{
    physical_t *p = getcomp(e, physical);
    fighter_t *f = getcomp(e, fighter);
    vec2 pos = physical_pos(e);
    vec2 direction = { 0, 0 };

    if(dist2(pos, physical_pos(g->player)) <= fix(0.25)) /* 0.5^2 */
        return;

    if(f->enemy && f->enemy->pathfind_cycles > 0) {
        direction = f->enemy->pathfind_dir;
        f->enemy->pathfind_cycles--;
    }
    else {
        pfg_path_t path = pfg_inwards(&g->paths_to_player, vec_f2i(pos));
        if(path.points) {
            direction = pfc_shortcut_one(&path, pos, physical_pos(g->player),
                p->hitbox);
            pfg_path_free(&path);
        }

        if(direction.x && direction.y) {
            direction.x -= pos.x;
            direction.y -= pos.y;
        }

        if(f->enemy) {
            f->enemy->pathfind_dir = direction;
            f->enemy->pathfind_cycles = 4;
        }
    }

    mechanical_move(e, direction, dt, g->map);
    if(direction.x > 0) p->facing = RIGHT;
    else if(direction.x < 0) p->facing = LEFT;
    else if(p->x < getcomp(g->player, physical)->x) p->facing = RIGHT;
    else p->facing = LEFT;
}

static bool move_within_range_of_player(game_t *g, entity_t *e, fixed_t range,
    fixed_t dt)
{
    if(dist2(physical_pos(e), physical_pos(g->player)) <= fmul(range, range))
        return true;

    move_towards_player(g, e, dt);
    return false;
}

static bool move_away_from_player_range(game_t *g, entity_t *e, fixed_t range,
    fixed_t dt)
{
    physical_t *p = getcomp(e, physical);
    fighter_t *f = getcomp(e, fighter);
    if(!p || !f || !f->enemy)
        return true;

    if(dist2(physical_pos(e), physical_pos(g->player)) > fmul(range, range))
        return true;

    /* Escape opposite the direction of normal movement */
    vec2 direction = f->enemy->pathfind_dir;
    direction = (vec2){ -direction.x, -direction.y };

    mechanical_move(e, direction, dt, g->map);
    if(p->x < getcomp(g->player, physical)->x) p->facing = RIGHT;
    else p->facing = LEFT;

    return false;
}

static bool contact_attack(game_t *g, entity_t *e)
{
    fighter_t *f = getcomp(e, fighter);
    if(f->current_attack)
        return false;

    physical_t *p = getcomp(e, physical);
    physical_t *player_p = getcomp(g->player, physical);

    vec2 dir = { player_p->x - p->x, player_p->y - p->y };
    dir = fnormalize(dir);

    entity_t *aoe = aoe_make_attack(AOE_HIT, e, dir);
    game_add_entity(g, aoe);

    f->current_attack = aoe;
    f->attack_follows_movement = true;
    visible_set_anim(e, f->enemy->id->anim_attack, 2);

    return true;
}

static bool use_skill_towards_player(game_t *g, entity_t *e, int slot)
{
    physical_t *p = getcomp(e, physical);
    physical_t *player_p = getcomp(g->player, physical);

    vec2 dir = { player_p->x - p->x, player_p->y - p->y };
    dir = fnormalize(dir);

    return skill_use(g, e, slot, dir);
}

void enemy_ai(game_t *g, entity_t *e, fixed_t dt)
{
    fighter_t *f = getcomp(e, fighter);

    if(f->enemy->id == &slime_1) {
        if(move_within_range_of_player(g, e, fix(0.5), dt)) {
            contact_attack(g, e);
        }
    }

    else if(f->enemy->id == &bat_2 || f->enemy->id == &albinos_bat_6) {
        struct bat_ai *ai_data = f->enemy->ai_data;

        /* After an attack, move away for a couple of seconds */
        if(ai_data->retreat_period > 0) {
            move_away_from_player_range(g, e, fix(3.0), dt);
            ai_data->retreat_period = max(ai_data->retreat_period-dt, fix(0));
        }
        /* Otherwise, get close and attack */
        else {
            /* Albinos bats try and use their speed skills whenever possible */
            if(f->enemy->id == &albinos_bat_6) {
                skill_use(g, e, 1, (vec2){0,0});
            }

            if(move_within_range_of_player(g, e, fix(0.5), dt)) {
                contact_attack(g, e);
                ai_data->retreat_period = fix(1.5);
            }
        }
    }

    else if(f->enemy->id == &fire_slime_4 || f->enemy->id == &water_slime_8
            || f->enemy->id == &chemical_slime_10) {
        if(move_within_range_of_player(g, e, fix(0.75), dt)) {
            /* Use the fire charge attack; if it fails, normal attack */
            if(use_skill_towards_player(g, e, 1)) {
                if(f->enemy->id == &fire_slime_4)
                    visible_set_anim(e, &anims_fire_slime_Fire, 2);
                if(f->enemy->id == &water_slime_8)
                    visible_set_anim(e, &anims_water_slime_Fire, 2);
                if(f->enemy->id == &chemical_slime_10)
                    visible_set_anim(e, &anims_chemical_slime_Fire, 2);
            }
            else {
                contact_attack(g, e);
            }
        }
    }

    else if(f->enemy->id == &gunslinger_8) {
        rect hitbox = { fix(-1/16), fix(1/16), fix(-1/16), fix(1/16) };
        bool clear = raycast_clear_hitbox(g->map, physical_pos(e),
            physical_pos(g->player), hitbox);

        if(clear)
            use_skill_towards_player(g, e, 0);
        else
            move_towards_player(g, e, dt);
    }
}