#include "main.h"
#include "entity.h"
#include "loader.h"
#include "tilemap.h"
#include <stdbool.h>
#include <math.h>
#include "particles.h"
#include "gun.h"

#define HP 15
#define WIDTH 8
#define HEIGHT 10
#define ACCELERATION 1
#define FRICTION 2
#define MAX_SPEED 8
#define GRAVITY 1
#define WALKABLE_CHECK_DISTANCE 8
#define DETECTION_RANGE to_fixed(80)
#define GIVE_UP_RANGE to_fixed(128)
#define FAR_RANGE to_fixed(56)
#define NEAR_RANGE to_fixed(40)
#define COLLISION_DAMAGE 1
#define COLLISION_IFRAMES 60

struct pacer_ext {
	unsigned detection_range, give_up_range;
	signed facing;
	struct gun primary, secondary;
};

enum {
	PACER_NONE,
	PACER_FALL,
	PACER_IDLE,
	PACER_PATROL,
	PACER_ALERT_NEAR,
	PACER_ALERT_APPROACH,
	PACER_ALERT_HALT_FAR,
	PACER_ALERT_FAR,
	PACER_ALERT_BACK_AWAY,
	PACER_ALERT_HALT_NEAR,
};

enum {
	PACER_A_IDLE,
	PACER_A_IDLE2,
	PACER_A_REST,
	PACER_A_WALK,
	PACER_A_WALK2,
	PACER_A_WALK3,
	PACER_A_WALK4,
};

static struct anim pacer_anims[] = {
	{PACER_A_IDLE2, {0, 0, 16, 16}, 300},
	{PACER_A_IDLE, {16, 0, 16, 16}, 2},
	{PACER_A_REST, {16, 0, 16, 16}, 300},
	{PACER_A_WALK2, {0, 0, 16, 16}, 6},
	{PACER_A_WALK3, {32, 0, 16, 16}, 6},
	{PACER_A_WALK4, {0, 0, 16, 16}, 6},
	{PACER_A_WALK, {48, 0, 16, 16}, 6},
};

void hvy_blaster_new(struct gun *self, int x, int y);
void hvy_shotgun_new(struct gun *self, int x, int y);
void hvy_repeater_new(struct gun *self, int x, int y);
void hvy_chaingun_new(struct gun *self, int x, int y);
void hvy_launcher_new(struct gun *self, int x, int y);
void hvy_laser_new(struct gun *self, int x, int y);

static collision_T collide(struct entity *self) {
	return tilemap_area(tilemap, from_fixed(self->x) - WIDTH / 2, from_fixed(self->y) - HEIGHT, from_fixed(self->x) + WIDTH / 2, from_fixed(self->y));
}

static int move(struct entity *self, signed direction) {
	int on_ground = false;
	int const dx = direction * ACCELERATION;
	self->velocity.x += dx;
	// deaccel
	if (dx == 0) {
		if (self->velocity.x < -FRICTION) {
			self->velocity.x += FRICTION;
		} else if (self->velocity.x > FRICTION) {
			self->velocity.x -= FRICTION;
		} else {
			self->velocity.x = 0;
		}
	}
	// speed cap
	if (self->velocity.x > MAX_SPEED) {
		self->velocity.x = MAX_SPEED;
	} else if (self->velocity.x < -MAX_SPEED) {
		self->velocity.x = -MAX_SPEED;
	}
	// x collision
	self->x += self->velocity.x;
	collision_T const cx = collide(self);
	if (collision_solid(cx)) {
		if (self->velocity.x < 0) {
			self->x += to_fixed(8) - ((self->x - to_fixed(WIDTH / 2)) % to_fixed(8)); // left
		} else if (self->velocity.x == 0) {
			//fputs("what?\n", stderr);
		} else {
			self->x -= ((self->x + to_fixed(WIDTH / 2)) % to_fixed(8)); // right
		}
		self->velocity.x = 0;
	}
	self->velocity.y += GRAVITY;
	// y collision
	self->y += self->velocity.y;
	collision_T const cy = collide(self);
	if (collision_solid(cy)) {
		if (self->velocity.y < 0) {
			self->y += to_fixed(8) - ((self->y - to_fixed(HEIGHT)) % to_fixed(8)); // up
			self->velocity.y = 0;
		} else if (self->velocity.y == 0) {
			//fputs("what?\n", stderr);
		} else {
			self->y -= ((self->y) % to_fixed(8)); // down
			self->velocity.y = to_fixed(1); // crazy but it works
			on_ground = true;
		}
	}
	
	if (collision_hazard(cx | cy)) {
		self->hurt(self, (struct damage) {1, 60});
	}
	
	self->hitbox.left = from_fixed(self->x) - WIDTH / 2;
	self->hitbox.right = from_fixed(self->x) + WIDTH / 2;
	self->hitbox.top = from_fixed(self->y) - HEIGHT;
	self->hitbox.bottom = from_fixed(self->y);
	return on_ground;
}

static void anim(struct entity *self, unsigned anim) {
	self->anim = pacer_anims[anim];
}

static inline int is_walkable(int const x, int const y) {
	collision_T const front1 = tilemap_tile(tilemap, from_fixed(x), from_fixed(y) - 4);
	collision_T const front2 = tilemap_tile(tilemap, from_fixed(x), from_fixed(y) - 10);
	collision_T const floor = tilemap_tile(tilemap, from_fixed(x), from_fixed(y) + 4);
	return !collision_solid(front1) && !collision_solid(front2) && collision_solid(floor) && !collision_hazard(floor);
}

static void pacer_free(struct entity *self) {
	self->state = 0;
	free(self->ext), self->ext = NULL;
}

static int pacer_update(struct entity *self) {
	struct pacer_ext *const ext = self->ext;
	if (self->hp <= 0) {
		pacer_free(self);
		entities.enemies--;
		return 1;
	}
	switch (self->state) {
		case PACER_IDLE:
			move(self, 0);
			ext->primary.update(&ext->primary, self, NULL);
			ext->secondary.update(&ext->secondary, self, NULL);
			if (abs(entities.player[0].x - self->x) + abs(entities.player[0].y - self->y) < ext->detection_range) {
				self->facing = self->x > entities.player[0].x? -1: 1;
				anim(self, PACER_A_WALK);
				self->state = PACER_ALERT_APPROACH;
			}
			break;
		
		case PACER_ALERT_NEAR:
			move(self, 0);
			self->facing = self->x > entities.player[0].x? -1: 1;
			if (ext->primary.update(&ext->primary, self, NULL)) {
				anim(self, PACER_A_WALK);
				self->state = PACER_ALERT_BACK_AWAY;
			}
			if (abs(entities.player[0].x - self->x) + abs(entities.player[0].y - self->y) > ext->give_up_range) {
				anim(self, PACER_A_REST);
				self->state = PACER_IDLE;
			}
			break;

		case PACER_ALERT_APPROACH:
			move(self, self->facing);
			if (hitbox_overlap(self->hitbox, entities.player[0].hitbox)) {
				entities.player[0].hurt(entities.player + 0, (struct damage) {COLLISION_DAMAGE, COLLISION_IFRAMES});
			}
			if (abs(entities.player[0].x - self->x) < NEAR_RANGE || !is_walkable(self->x + to_fixed(self->facing * WALKABLE_CHECK_DISTANCE), self->y)) {
				anim(self, PACER_A_IDLE);
				self->state = PACER_ALERT_HALT_NEAR;
			}
			break;

		case PACER_ALERT_HALT_NEAR: // velocity affects bullets
			move(self, 0);
			if (self->velocity.x == 0) {
				if (ext->primary.update(&ext->primary, self, entities.player)) {
					anim(self, PACER_A_IDLE);
					self->state = PACER_ALERT_NEAR;
				}
			}
			break;

		case PACER_ALERT_FAR:
			move(self, 0);
			self->facing = self->x > entities.player[0].x? -1: 1;
			if (ext->secondary.update(&ext->secondary, self, NULL)) {
				anim(self, PACER_A_WALK);
				self->state = PACER_ALERT_APPROACH;
			}
			if (abs(entities.player[0].x - self->x) + abs(entities.player[0].y - self->y) > ext->give_up_range) {
				anim(self, PACER_A_REST);
				self->state = PACER_IDLE;
			}
			break;

		case PACER_ALERT_BACK_AWAY:
			move(self, -self->facing);
			if (hitbox_overlap(self->hitbox, entities.player[0].hitbox)) {
				entities.player[0].hurt(entities.player + 0, (struct damage) {COLLISION_DAMAGE, COLLISION_IFRAMES});
			}
			if (abs(entities.player[0].x - self->x) > FAR_RANGE || !is_walkable(self->x + to_fixed(-self->facing * WALKABLE_CHECK_DISTANCE), self->y)) {
				anim(self, PACER_A_IDLE);
				self->state = PACER_ALERT_HALT_FAR;
			}
			break;

		case PACER_ALERT_HALT_FAR: // velocity affects bullets
			move(self, 0);
			if (self->velocity.x == 0) {
				if (ext->secondary.update(&ext->secondary, self, entities.player)) {
					anim(self, PACER_A_IDLE);
					self->state = PACER_ALERT_FAR;
				}
			}
			break;
	}
	if (self->iframes > 0) {
		self->iframes--;
	}
	self->anim.length--;
	if (self->anim.length == 0) {
		anim(self, self->anim.frame);
	}
	return 0;
}

static int pacer_hurt(struct entity *self, struct damage damage) {
	if (self->iframes == 0) {
		self->hp -= damage.damage;
		self->iframes = damage.iframes;
		for (int x = -1; x <= 1; x += 2) {
			for (int y = -1; y <= 1; y += 2) {
				struct particle *part = entities.particle + entities.particles;
				part->x = self->x;
				part->y = self->y;
				part->velocity = (struct vec2) {to_fixed(x) * 1.5, to_fixed(y) * 1.5};
				part->rect = particle_white;
				part->acceleration = (struct vec2) {-x, -y};
				part->hp = 24;
				entities.particles++;
			}
		}
	}
	return 0;
}

static int pacer_draw(struct entity *self, int camX, int camY) {
	if (!(self->iframes & 0x4)) {
		SDL_Rect rect = self->anim.rect;
		if (self->facing == -1) {
			rect.y += 16;
		}
		SDL_RenderCopy(renderer, self->texture, &rect, &(SDL_Rect) {from_fixed(self->x) - camX - 8, from_fixed(self->y) - camY - 16, 16, 16});
	}
	return 0;
}

struct entity *pacer_new(struct entities *entities) {
	struct entity *self = entities->enemy + entities->enemies;
	*self = (struct entity) {
		.update = pacer_update,
		.hurt = pacer_hurt,
		.draw = pacer_draw,
		.free = pacer_free,
		.x = 0, .y = 0,
		.velocity = {.x = 0, .y = 0},
		.hitbox = {
			0, 0, 0, 0,
		},
		.state = PACER_IDLE,
		.hp = HP,
		.timer = 0,
		.facing = 1,
		.faction = FACTION_ENEMY,
		.iframes = 0,
		.texture = NULL,
		.ext = NULL,
	};
	self->ext = malloc(sizeof (struct pacer_ext));
	*(struct pacer_ext *) self->ext = (struct pacer_ext) {
		.detection_range = DETECTION_RANGE,
		.give_up_range = GIVE_UP_RANGE,
		.facing = 1,
	};
	struct pacer_ext *ext = self->ext;
	hvy_repeater_new(&ext->primary, 5, -6);
	hvy_blaster_new(&ext->secondary, 5, -6);
	anim(self, PACER_A_REST);
	self->texture = res_get_texture("pacer").data;
	entities->enemies++;
	return self;
}

int pacer_property(struct entity *const restrict self, char const *const restrict property, char const *const restrict value) {
	struct pacer_ext *const ext = self->ext;
	if (strcmp(property, "x") == 0) {
		self->x = to_fixed(atoi(value));
	} else if (strcmp(property, "y") == 0) {
		self->y = to_fixed(atoi(value));
	} else if (strcmp(property, "detection range") == 0) {
		ext->detection_range = to_fixed(atoi(value));
	} else if (strcmp(property, "give up range") == 0) {
		ext->give_up_range = to_fixed(atoi(value));
	} else {
		return 1;
	}
	return 0;
}