--[[
Copyright (c) 2013 Julius Riecke

This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:

   1. The origin of this software must not be misrepresented; you must not
   claim that you wrote the original software. If you use this software
   in a product, an acknowledgment in the product documentation would be
   appreciated but is not required.

   2. Altered source versions must be plainly marked as such, and must not be
   misrepresented as being the original software.

   3. This notice may not be removed or altered from any source
   distribution.
]]

SCRIPT_TITLE	= "Gradius - Bullet Hell"
SCRIPT_VERSION	= "1.0"

require "m_utils"
m_require("m_utils",0)

--[[
Gradius - Bullet Hell
version 1.0 by Julius Riecke

Visit http://morphcat.de/lua/ for the most recent version and other scripts.


Controls
	Press select to fire a bomb that will destroy all enemy bullets and grant you
	invincibility for a short period of time.

Supported roms
	Gradius (J), Gradius (U), Gradius (E)

Known bugs
	- dying from blue bullets doesn't trigger the death sound effect
-]]

--configurable vars
local BOMBS_PER_LIFE = 5
local HITBOX = {-2, 4, 9, 9} --vic viper's hit box for collision detection with blue bullets
--------------------------------------------------------------------------------------------



local MAX_EXSPR = 64
local timer = 0
local spr = {}
local exspr = {}
local exsprdata = {}
local deathtimer = 0
local bombtimer = 0
local paused = 0
local bombs = BOMBS_PER_LIFE
local bulletimg = ""


function makebinstr(t)
	local str = ""
	for i,v in ipairs(t) do
		str = str..string.char(v)
	end
	return str
end

function initialize()
	--Transparency doesn't seem to work for gd images, bummer!
	bulletimg = makebinstr( {
			0xff, 0xfe,    0,  0x6,    0,  0x6,  0x1, 0xff,
			0xff, 0xff, 0xff,    0,    0,    0,    0,    0,
			   0,    0,    0,    0,  0x2, 0x33, 0x6e,    0,
			 0x2, 0x33, 0x6e,    0,    0,    0,    0,    0,
			   0,    0,    0,    0,    0,    0,    0,    0,
			 0x2, 0x33, 0x6e,    0, 0x4d, 0xb6, 0xff,    0,
			0xdb, 0xff, 0xfc,    0,  0x2, 0x33, 0x6e,    0,
			   0,    0,    0,    0,  0x2, 0x33, 0x6e,    0,
			0x4d, 0xb6, 0xff,    0, 0x4d, 0xb6, 0xff,    0,
			0xdb, 0xff, 0xfc,    0, 0xdb, 0xff, 0xfc,    0,
			 0x2, 0x33, 0x6e,    0,  0x2, 0x33, 0x6e,    0,
			0xdb, 0xff, 0xfc,    0, 0xdb, 0xff, 0xfc,    0,
			0x4d, 0xb6, 0xff,    0, 0x4d, 0xb6, 0xff,    0,
			 0x2, 0x33, 0x6e,    0,    0,    0,    0,    0,
			 0x2, 0x33, 0x6e,    0, 0xdb, 0xff, 0xfc,    0,
			0x4d, 0xb6, 0xff,    0,  0x2, 0x33, 0x6e,    0,
			   0,    0,    0,    0,    0,    0,    0,    0,
			   0,    0,    0,    0,  0x2, 0x33, 0x6e,    0,
			 0x2, 0x33, 0x6e,    0,    0,    0,    0,    0,
			   0,    0,    0 } )

	for i=0,31 do
		spr[i] = {
					status=0,
					id=0,
					x=0,
					y=0,
					timer=-1,
				}
	end
end


function createexsprite(s)
	for i=0,MAX_EXSPR-1 do
		if(exspr[i]==nil) then
			exspr[i]=s
			if(exspr[i].id==nil) then
				exspr[i].id=0
			end
			if(exspr[i].x==nil) then
				exspr[i].x=0
			end
			if(exspr[i].y==nil) then
				exspr[i].y=0
			end
			if(exspr[i].vx==nil) then
				exspr[i].vx=0
			end
			if(exspr[i].vy==nil) then
				exspr[i].vy=0
			end
			if(exspr[i].timer==nil) then
				exspr[i].timer=0
			end
			if(exspr[i].ai==nil) then
				exspr[i].ai=""
			end
			return exspr[i]
		end
	end
	return nil
end

function destroyallexsprites()
	exspr = {}
end

function destroyexsprite(i)
	exspr[i] = nil
end

function destroysprite(i)
	memory.writebyte(0x100+i,0x00)
	memory.writebyte(0x120+i,0x00)
	memory.writebyte(0x300+i,0x00)
end


function drawexsprite(id,x,y)
	gui.gdoverlay(x, y, bulletimg)
end


function getvicdistance(x,y)
	return getdistance(vic.x+4,vic.y+8,x,y)
end

function doexspriteai(s)
	if(s.ai=="Stray") then
		if(s.timer==0) then
			s.vx = -3
			s.vy = AND(timer,0x0F) / 8 - 1
		end
	elseif(s.ai=="AimOnce") then
		if(s.timer==0) then
			s.vx,s.vy = get_vdir(s,vic)
			s.vx = s.vx * 2
			s.vy = s.vy * 2
			--s.vy = AND(timer,0x0F) / 8 - 1
		end
	elseif(s.ai=="AimDelayed") then
		if(s.timer>=30 and s.timer<=33) then
			local x,y = get_vdir(s,vic)
			s.vx = (x+s.vx)
			s.vy = (y+s.vy)
		end
	elseif(s.ai=="AimRight") then
		if(s.timer==0) then
			s.vx,s.vy = get_vdir(s,vic)
			s.vx = s.vx * 2.5
			s.vy = s.vy * 1.5
		end
	elseif(s.ai=="AimLeft") then
		if(s.timer==0) then
			s.vx,s.vy = get_vdir(s,vic)
			s.vx = s.vx * 1.5
			s.vy = s.vy * 2.5
		end
	elseif(s.ai=="BossPattern1") then
		if(s.timer==0) then
			s.vx = math.random(-100,0)/50
			s.vy = math.random(-100,0)/70
		elseif(s.timer>=30 and s.timer <=35) then
			s.vx=s.vx/1.1
			s.vy=s.vy/1.1
		elseif(s.timer==70) then
			local x,y = get_vdir(s,vic)
			s.vx = x*3
			s.vy = y*3
		end
	elseif(s.ai=="LimitedLifeSpan") then
		if(s.timer>120) then
			s.x=999 --results in death
		end
	end
	
	if(s.timer>600) then --delete extended sprites after 10 seconds in case one gets stuck on screen
		s.x=999
	end
end

function doboss1ai(s)
	if(s.timer>80 and s.timer<320 and AND(s.timer,63)==0) then
		createexsprite({x=s.x,y=s.y,ai="BossPattern1"})
		createexsprite({x=s.x,y=s.y,ai="BossPattern1"})
		createexsprite({x=s.x,y=s.y,ai="BossPattern1"})
		createexsprite({x=s.x,y=s.y,ai="BossPattern1"})
		createexsprite({x=s.x,y=s.y,ai="BossPattern1"})
		createexsprite({x=s.x,y=s.y,ai="BossPattern1"})
		createexsprite({x=s.x,y=s.y,ai="BossPattern1"})
	end
	if(s.timer>320 and s.timer<520) then --pattern2 a
		if(math.mod(s.timer,27)<=9 and AND(s.timer,3)==3) then
			createexsprite({x=s.x,y=s.y,vx=-0.2,ai="AimDelayed"})
		end
	end
	if(s.timer>320 and s.timer<520) then --pattern2 b
		if(AND(s.timer,63)==0) then
			createexsprite({x=s.x,y=s.y,vx=-0.7,vy=-1.6})
			createexsprite({x=s.x,y=s.y,vx=-1.1,vy=-0.8})
			createexsprite({x=s.x,y=s.y,vx=-1.2,vy=-0})
			createexsprite({x=s.x,y=s.y,vx=-1.1,vy=0.8})
			createexsprite({x=s.x,y=s.y,vx=-0.7,vy=1.6})
		end
	elseif(s.timer>520) then
		s.timer = 60
	end
end


function dospriteai(s)
	if(s.id==0x85) then --Fan
		if(s.timer==30) then
			createexsprite({x=s.x,y=s.y,ai="Stray"})
		end
	elseif(s.id==0x86) then --Jumper
		if(AND(s.timer,127)==40) then
			createexsprite({x=s.x,y=s.y,vx=-1.5,vy=-0.5})
			createexsprite({x=s.x,y=s.y,vx=-1,vy=-1.1})
			createexsprite({x=s.x,y=s.y,vx=0,vy=-1.4})
			createexsprite({x=s.x,y=s.y,vx=1,vy=-1.1})
			createexsprite({x=s.x,y=s.y,vx=1.5,vy=-0.5})
		end
	elseif(s.id==0x88) then --Rugul
		if(AND(s.timer,63)==30) then
			createexsprite({x=s.x,y=s.y,ai="Stray"})
		end
	elseif(s.id==0x84 or s.id==0x9C) then --Fose, Uska(?)
		if(AND(s.timer,63)==30) then
			createexsprite({x=s.x,y=s.y,vx=0,vy=-2})
		elseif(AND(s.timer,63)==60) then
			createexsprite({x=s.x,y=s.y,vx=0,vy=2})
		end
	elseif(s.id==0x89 or s.id==0x8C) then --Rush
		if(AND(timer,63)==5) then
			createexsprite({x=s.x,y=s.y,vx=-1,vy=-1})
		end
	elseif(s.id==0x96) then --Moai
	elseif(s.id==0x97) then --Mother and Child
		if(AND(timer,7)==0) then
			local t = s.timer/15
			createexsprite({x=s.x+16,y=s.y+16,vx=math.sin(t)-1,vy=math.cos(t),ai="LimitedLifeSpan"})
		end
	elseif(s.id==0x8B) then --Zabu
		if(s.timer==5) then
			createexsprite({x=s.x,y=s.y,vx=0.5,ai="AimDelayed"})
		end
	elseif(s.id==0x92 or s.id==0x93 or s.id==0x87 or s.id==0x91) then --Dee-01, Ducker
		--if(s.timer==5) then
		local t = AND(s.timer,127)
		if(t>60 and t<79 and AND(s.timer,3)==3) then
			--createexsprite({x=s.x,y=s.y,ai="AimOnce"})
			createexsprite({x=s.x,y=s.y,ai="AimOnce"})
		end
	elseif(s.id==0x98) then --boss...
		doboss1ai(s)
	end
end


function updatevars()
	paused = memory.readbyte(0x0015)
	if(paused==1) then
		return
	end
	--load original sprites from ram
	for i=0,31 do
		--if(i==0 or memory.readbyte(0x0300+i)~=0) then
			if(memory.readbyte(0x0300+i)~=spr[i].id) then
				spr[i].timer = 0
			end
			spr[i].status=memory.readbyte(0x0100+i) --1=alive, 2=dead
			spr[i].id=memory.readbyte(0x0300+i)
			spr[i].x=memory.readbyte(0x0360+i)
			spr[i].y=memory.readbyte(0x0320+i)
			spr[i].timer=spr[i].timer+1
			if(spr[i].id==0) then
				spr[i].timer = 0
			else
				dospriteai(spr[i])
			end
			
			if(i>3 and bombtimer>0 and getvicdistance(spr[i].x+4,spr[i].y+4)<30) then
				if(spr[i].id~=0x29 and spr[i].id~=0x01 and spr[i].id~=0x99 and spr[i].id~=0x98 and spr[i].id~=0x94 and spr[i].id~=0x97 and spr[i].id~=0x96 and spr[i].id~=0x1E) then
				--excluded: hidden bonus (0x29), power ups and moai bullets (0x01), boss (0x99+0x98), tentacle (0x94), mother (0x97), moai (0x96), gate (0x1E)
					destroysprite(i)
				end
			end
		--end
	end
	vic = spr[0]
	

	
	
	if(deathtimer>0) then
		if(deathtimer==120) then
			destroyallexsprites()
			deathtimer = 0
			bombs = BOMBS_PER_LIFE
		else
			if(deathtimer==1) then
			--this is part of what gradius does to kill vic viper...
			--faster and without the annoying sound effect. who cares!
			memory.writebyte(0x4C,0x78)
			memory.writebyte(0x0100,0x02) --status = dead
			memory.writebyte(0x0160,0x00)
			memory.writebyte(0x0140,0x00)
			memory.writebyte(0x1B,0xA0)
			memory.writebyte(0x0120,0x2D) --chr?--
			end
			deathtimer = deathtimer + 1
		end
	end
	

	local jp = joypad.get(1)
	if(jp.select and jp.select~=last_select and bombs>0) then
		bombtimer = 1
		bombs = bombs - 1
		destroyallexsprites()
		--destroy bullets
		for i=1,31 do
			if(spr[i].id<4 and spr[i].id~=1) then
				destroysprite(i)
			end
		end
	end
	last_select = jp.select

	
	if(last_vic_status~=vic.status) then
		if(vic.status==2) then --vic died in the original game, start death timer to destroy all extended sprites
			deathtimer = 1
		end
	end
	last_vic_status = vic.status
	
	--calculations on extended sprites
	for i=0,MAX_EXSPR-1 do
		if(exspr[i]~=nil) then
			if(bombtimer>0 and getvicdistance(exspr[i].x+4,exspr[i].y+4)<25) then
				destroyexsprite(i)
			else
			doexspriteai(exspr[i])
			exspr[i].timer = exspr[i].timer + 1
			exspr[i].x=exspr[i].x+exspr[i].vx
			exspr[i].y=exspr[i].y+exspr[i].vy
			if(exspr[i].x>255 or exspr[i].x<0 or exspr[i].y>255 or exspr[i].y<0) then
				--destroy exsprite
				exspr[i]=nil
				break
			end
				--collision check with vic viper
				if(deathtimer==0 and vic.status==1 and exspr[i].x>=vic.x+HITBOX[1] and exspr[i].x<=vic.x+HITBOX[3]
					and exspr[i].y>=vic.y+HITBOX[2] and exspr[i].y<=vic.y+HITBOX[4]) then
					deathtimer = 1
				end
			end
		end
	end
	
	
end

function render()
	--bcbox(vic.x-2, vic.y+4, vic.x+9, vic.y+9, "#ffffff")
	
	gui.text(0, 8, string.format("bombs %d",bombs));
	--gui.text(0, 8, string.format("Lives %d",memory.readbyte(0x0020)));
	--gui.text(0, 28, string.format("bombtimer %d",bombtimer));
	
	--[[for i=1,31 do
		if(spr[i].id~=0) then
			gui.text(spr[i].x, spr[i].y, string.format("%X",spr[i].id));
		end
	end--]]
	
	for i=0,MAX_EXSPR-1 do
		if(exspr[i]~=nil) then
			drawexsprite(exspr[i].id,exspr[i].x,exspr[i].y)
		end
	end
	
	
	if(bombtimer>0) then
		if(bombtimer<12) then
			memory.writebyte(0x11,0xFF) --monochrome screen
		else
			memory.writebyte(0x11,0x1E)
		end
		bombtimer = bombtimer + 1
		for i=0,64 do
			local x = vic.x+4+math.sin(i)*bombtimer*4 + math.random(0,12)
			local y = vic.y+8+math.cos(i)*bombtimer*4 + math.random(0,12)
			local c = 255-bombtimer
			local cs = string.format("#%02x%02x00",c,c)
			bcpixel(x,y,cs)
			bcpixel(x-1,y,cs)
			bcpixel(x+1,y,cs)
			bcpixel(x,y+1,cs)
			bcpixel(x,y-1,cs)
			
			x = vic.x+4+math.sin(i)*(20+math.sin(bombtimer/5))
			y = vic.y+8+math.cos(i)*(20+math.sin(bombtimer/5))
			bcpixel(x,y,cs)
			bcpixel(x-1,y,cs)
			bcpixel(x,y-1,cs)
		end
		if(bombtimer==180) then
			bombtimer=0
		end
	end
end


initialize()
vic = spr[0]
while(true) do
	updatevars()
	render()
	EMU.frameadvance()
	timer = timer + 1
end