#include "animation.h"
#include "asset.h"
#include "config.h"
#include "maths.h"
#include "obj.h"
#include "physics.h"
#include "render.h"
#include "world.h"

enum {
	enemy_state_patrol,
	enemy_state_approach,
	enemy_state_approach2,
	enemy_state_attack
};

int get_enemy_hp(Enemy_Type t) {
	switch (t) {
		case enemy_demon:
			return 3;
	}
	return 0;
}

void get_enemy_rect(Enemy_Type t, Rect* d) {
	switch (t) {
		case enemy_demon:
			d->x = 2;
			d->y = 2;
			d->w = 12;
			d->h = 14;
			break;
	}
}

void init_enemy(Enemy* e, Enemy_Type t, int x, int y) {
	e->t = t;
	e->x = x;
	e->y = y;
	e->vx = 0;
	e->vy = 0;
	e->hp = get_enemy_hp(t);
	e->frame = 0;
	e->anim = asset_id_demon_idle_left_anm;
	e->face = face_left;
	e->state = enemy_state_patrol;
	e->inv = 0;
}

void update_enemy_anim(Enemy* e) {
	int done;
	const Animation* anim = get_animation(e->anim);
	done = update_anim(anim, &e->frame, &e->rect);
	if (
		done &&
		e->t == enemy_demon &&
		e->state == enemy_state_approach
	) {
		e->state = enemy_state_approach2;
	}
}

void update_enemy_phys(Enemy* e, const Map* map) {
	Rect r;
	get_enemy_rect(e->t, &r);
	r.x <<= fbits;
	r.y <<= fbits;
	r.w <<= fbits;
	r.h <<= fbits;
	update_body(
		map,
		&e->x,
		&e->y,
		&e->vx,
		&e->vy,
		&e->grounded,
		&e->headbutted,
		&e->on_ramp,
		&r
	);
}

void update_enemy_hurt(Enemy* e, World* w) {
	Rect a;
	int i, cx, cy;
	if (e->inv)	{
		e->inv--;
		return;
	}
	get_enemy_rect(e->t, &a);
	a.x += e->x >> fbits;
	a.y += e->y >> fbits;
	cx = (a.x << fbits) + ((a.w >> 1) << fbits);
	cy = (a.y << fbits) + ((a.h >> 1) << fbits);
	for (i = 0; i < w->deathzone_count; i++) {
		const Deathzone* dz = &w->deathzones[i];
		if (dz->friendly && rects_overlap(&a, &dz->r)) {
			e->hp -= dz->hp;
			e->vx -= dz->vx;
			e->vy -= dz->vy;
			e->inv = enemy_inv_frames;
			w->player.charge++;
			w->freeze += enemy_hurt_freeze;
			inst_effect(w, cx, cy, -dz->vx, -dz->vy, 32);
		}
	}
}

int tile_at(const Map* m, int x, int y) {
	return
		x < 0 ||
		y < 0 ||
		x >= map_w ||
		y >= map_h ||
		m->collision[x + y * map_w] == 1;
}

void update_demon_move(Enemy* e, World* w) {
	int nanim = e->anim;
	const Player* p = &w->player;
	if (e->state == enemy_state_patrol) {
		int dx = e->x - p->x;
		int dy = e->y - p->y;
		int dx2 = dx >> fbits;
		int dy2 = dy >> fbits;
		int dist = fxsqrt(dx * dx2 + dy * dy2) >> fbits;
		if (e->grounded < 3) {
			int tx, ty =
				((e->y >> fbits) + (map_tile_size >> 1)) /
				map_tile_size;
			int ty2 = ty + 1;
			if (e->face == face_left) {
				tx = (
					(e->x >> fbits) - (map_tile_size >> 1)) /
					map_tile_size;
			} else {
				tx = (
					(e->x >> fbits) + map_tile_size +
					(map_tile_size >> 1)) /
					map_tile_size;
			}
			if (
				tile_at(&w->map, tx, ty) ||
				(!e->on_ramp && ty2 < map_h && !tile_at(&w->map, tx, ty2))
			)
				e->face = !e->face;
			if (e->face == face_left) {
				e->vx -= enemy_demon_move_force;
			} else {
				e->vx += enemy_demon_move_force;
			}
		}
		if (dist < enemy_demon_attack_dist) {
			e->state = enemy_state_approach;
		}
	} else if (e->state == enemy_state_approach) {
		if (p->x < e->x)
			e->face = face_left;
		else
			e->face = face_right;
	} else if (e->state == enemy_state_approach2) {
		if (e->grounded < 3) {
			e->vx = (p->x - e->vx) / 120;
			if (e->face == face_left)
				e->vx = -e->vx;
			e->vy = -enemy_demon_jump_force;
			e->grounded = 100;
			e->state = enemy_state_attack;
		}
	} else if (e->state == enemy_state_attack) {
		if (e->grounded < 3) {
			Asset_ID sl;
			Rect dz;
			int sx, sy = e->y >> fbits, vx;
			if (e->face == face_left) {
				sl = asset_id_smol_slash_left_anm;
				sx = (e->x >> fbits) - 16;
				vx = enemy_knockback;
			} else {
				sl = asset_id_smol_slash_right_anm;
				sx = (e->x >> fbits) + 16;
				vx = -enemy_knockback;
			}
			dz.x = sx;
			dz.y = sy;
			dz.w = 16;
			dz.h = 12;
			inst_particle(w, sx, sy, sl, asset_id_arms_img);
			inst_deathzone(w, &dz, vx, 0, enemy_slash_damage, 4, 0);
			e->state = enemy_state_patrol;
		}
	}
	switch (e->face) {
		case face_left:
			nanim =
				e->state == enemy_state_patrol?
					asset_id_demon_walk_left_anm:
				e->state == enemy_state_approach?
					asset_id_demon_jump_left_anm:
				asset_id_demon_idle_left_anm;
			break;
		case face_right:
			nanim =
				e->state == enemy_state_patrol?
					asset_id_demon_walk_right_anm:
				e->state == enemy_state_approach?
					asset_id_demon_jump_right_anm:
				asset_id_demon_idle_right_anm;
			break;
	}
	if (nanim != e->anim) {
		e->frame = 0;
		e->anim = nanim;
	}
}

void update_enemy_move(Enemy* e, World* w) {
	switch (e->t) {
		case enemy_demon:
			update_demon_move(e, w);
			break;
	}
}

int update_enemy(Enemy* e, World* w) {
	update_enemy_anim(e);
	update_enemy_hurt(e, w);
	update_enemy_move(e, w);
	update_enemy_phys(e, &w->map);
	return e->hp <= 0;
}

void ren_enemy(const Enemy* e, struct Renderer* r) {
	const Bitmap* b = get_bitmap(asset_id_npc_img);
	ren_map(r, e->x >> fbits, e->y >> fbits, &e->rect, b);
}