package space_invaders

import "core:c"
import "core:log"
import glm "core:math/linalg/glsl"

import rl "vendor:raylib"

GLOBAL_SPRITE_SCALE :: 2

ALIEN_ROWS :: 5
ALIENS_PER_ROW :: 11
ALIENS :: ALIEN_ROWS * ALIENS_PER_ROW
ALIEN_SIDE_STEP :: 20 * GLOBAL_SPRITE_SCALE
ALIEN_RECT :: glm.ivec2{16 * GLOBAL_SPRITE_SCALE, 16 * GLOBAL_SPRITE_SCALE}

MAX_BULLETS :: 100
BULLET_SPEED :: 240
BULLET_RECT :: glm.ivec2{16 * GLOBAL_SPRITE_SCALE, 16 * GLOBAL_SPRITE_SCALE}

MAX_PLAYER_HEALTH :: 3
PLAYER_SPEED :: 40
PLAYER_RECT :: glm.ivec2{16 * GLOBAL_SPRITE_SCALE, 16 * GLOBAL_SPRITE_SCALE}

Alien :: struct {
	alive:    bool,
	position: glm.vec2,
	id:       int,
}

Bullet :: struct {
	alive:    bool,
	position: glm.vec2,
}

setup_game :: proc(state: ^GameState) {
	using state
	player_pos = glm.vec2{f32(screen_width / 2), f32(screen_height - PLAYER_RECT.x)}

	// setup the initial positions of the aliens
	for row in 0 ..< ALIEN_ROWS {
		for alien in 0 ..< ALIENS_PER_ROW {
			aliens[(row * ALIENS_PER_ROW) + alien].position = glm.vec2 {
				f32((alien + 1) * int(ALIEN_RECT.x + 10)),
				f32((row + 1) * int(ALIEN_RECT.x + 10)),
			}
		}
	}
}

update_game :: proc(state: ^GameState) {
	using state

	// If we're entering the game screen then we need to setup initial state of the game variables
	if last_frame_screen != .GAMEPLAY {
		setup_game(state)
		log.info("Done setting up game")
	}

	// Press enter to change to ENDING screen
	if (rl.IsKeyPressed(rl.KeyboardKey.ENTER)) {
		state.screen = .ENDING
		log.info("Updated screen enum", state.screen)
	}

	// Press space to change to fire
	if (rl.IsKeyPressed(rl.KeyboardKey.SPACE)) {
		log.info("FIRE!")
    bullet := &bullets[bullet_index]
    bullet.alive = true
    bullet.position = player_pos
    bullet.position.y = bullet.position.y - f32((PLAYER_RECT.y / 2) + BULLET_RECT.y / 2)
	}

	if (rl.IsKeyDown(rl.KeyboardKey.RIGHT)) {
		player_pos.x = player_pos.x + f32(PLAYER_SPEED * delta_time)
	}
	if (rl.IsKeyDown(rl.KeyboardKey.LEFT)) {
		player_pos.x = player_pos.x - f32(PLAYER_SPEED * delta_time)
	}

  // movement update
  {
    for &bullet in bullets {
      if bullet.alive {
        bullet.position.y = bullet.position.y - f32(BULLET_SPEED * delta_time)
      }
    }
  }
}

draw_game :: proc(state: ^GameState) {
	using state
	rl.DrawRectangle(0, 0, state.screen_width, state.screen_height, rl.BLACK)
	// rl.DrawText("GAMEPLAY SCREEN", 20, 20, 40, rl.MAROON)
	// rl.DrawText("PRESS ENTER or TAP to JUMP to ENDING SCREEN", 130, 220, 20, rl.MAROON)
	rl.DrawCircle(c.int(player_pos.x), c.int(player_pos.y), f32(PLAYER_RECT.x / 2), rl.RED)

	for row in 0 ..< ALIEN_ROWS {
		for alien in 0 ..< ALIENS_PER_ROW {
			alien := &aliens[(row * ALIENS_PER_ROW) + alien]
			rl.DrawCircle(
				c.int(alien.position.x),
				c.int(alien.position.y),
				f32(ALIEN_RECT.x / 2),
				rl.YELLOW,
			)
		}
	}

  for &bullet in bullets {
    if !bullet.alive { continue }
    rl.DrawCircle(c.int(bullet.position.x), c.int(bullet.position.y), f32(BULLET_RECT.x / 2), rl.WHITE)
  }

	// rl.DrawText("GAMEPLAY SCREEN", 20, 20, 40, rl.MAROON)
}