; VMW Chiptune Player

.include	"zp.inc"
				; program is ~4k, so from 0xc00 to 0x1C00
LZ4_BUFFER	EQU	$1C00		; $1C00 - $5C00, 16k for now
UNPACK_BUFFER	EQU	$5E00		; $5E00 - $9600, 14k, $3800
					; trying not to hit DOS at $9600
					; Reserve 3 chunks plus spare (14k)

NUM_FILES	EQU	15

	;=============================
	; Setup
	;=============================
	jsr     HOME
	jsr     TEXT

	; init variables

	lda	#0
	sta	DRAW_PAGE
	sta	CH
	sta	CV
	sta	DONE_PLAYING
	sta	XPOS
	sta	MB_CHUNK_OFFSET
	sta	DECODE_ERROR

	lda	#1
	sta	WHICH_FILE

	; print detection message

	lda	#<mocking_message		; load loading message
	sta	OUTL
	lda	#>mocking_message
	sta	OUTH
	jsr	move_and_print			; print it

	jsr	mockingboard_detect_slot4	; call detection routine
	cpx	#$1
	beq	mockingboard_found

	lda	#<not_message			; if not found, print that
	sta	OUTL
	lda	#>not_message
	sta	OUTH
	inc	CV
	jsr	move_and_print

	jmp	forever_loop			; and wait forever

mockingboard_found:
;	lda     #<found_message			; print found message
;	sta     OUTL
;	lda     #>found_message
;	sta     OUTH
;	inc     CV
;	jsr     move_and_print

	;============================
	; Init the Mockingboard
	;============================

	jsr	mockingboard_init
	jsr	reset_ay_both
	jsr	clear_ay_both

	;=========================
	; Setup Interrupt Handler
	;=========================
	; Vector address goes to 0x3fe/0x3ff
	; FIXME: should chain any existing handler

	lda	#<interrupt_handler
	sta	$03fe
	lda	#>interrupt_handler
	sta	$03ff

	;============================
	; Enable 50Hz clock on 6522
	;============================

	sei			; disable interrupts just in case

	lda	#$40		; Continuous interrupts, don't touch PB7
	sta	$C40B		; ACR register
	lda	#$7F		; clear all interrupt flags
	sta	$C40E		; IER register (interrupt enable)

	lda	#$C0
	sta	$C40D		; IFR: 1100, enable interrupt on timer one oflow
	sta	$C40E		; IER: 1100, enable timer one interrupt

	lda	#$E7
	sta	$C404		; write into low-order latch
	lda	#$4f
	sta	$C405		; write into high-order latch,
				; load both values into counter
				; clear interrupt and start counting

	; 4fe7 / 1e6 = .020s, 50Hz


	;============================
	; Draw title screen
	;============================

	jsr	set_gr_page0			; set page 0

	lda	#$4				; draw page 1
	sta	DRAW_PAGE

	jsr	clear_screens			; clear both screens

	lda	#<chip_title			; point to title data
	sta	GBASL
	lda	#>chip_title
	sta	GBASH

	; Load image				; load the image
	lda	#<$400
	sta	BASL
	lda	#>$400
	sta	BASH

	jsr	load_rle_gr

	;==================
	; load first song
	;==================

	jsr	new_song

	;============================
	; Init Background
	;============================
	jsr	set_gr_page0

	lda	#0
	sta	DRAW_PAGE
	sta	SCREEN_Y

	;============================
	; Enable 6502 interrupts
	;============================

	cli		; clear interrupt mask


	;============================
	; Loop forever
	;============================
main_loop:
	lda	DECODE_ERROR
	beq	check_copy
	sei
	brk

check_copy:
	lda	COPY_TIME
	beq	check_decompress	; if zero, skip

	lda	#0
	sta	COPY_OFFSET
check_copy_loop:
	jsr     page_copy                                               ;6+3621

	inc     COPY_OFFSET     ; (opt: make subtract?)                 ; 5

	lda	#14		; NOT HEX URGH!
	cmp	COPY_OFFSET
	bne	check_copy_loop

	lda	#0			; we are done
	sta	COPY_TIME

check_decompress:
	lda	DECOMPRESS_TIME
	beq	check_done		; if zero, skip

	jsr	setup_next_subsong	; decompress

	lda	MB_CHUNK_OFFSET
	sta	TIME_TAKEN

	lda	#0
	sta	DECOMPRESS_TIME

	;============================
	; visualization
	;============================
;	jsr	clear_top
;	jsr	draw_rasters
;	jsr	volume_bars
;	jsr	page_flip

check_done:
	lda	#$ff
	bit	DONE_PLAYING
	beq	main_loop	; if was all zeros, loop
	bmi	main_loop	; if high bit set, paused
	bvs	minus_song	; if bit 6 set, then left pressed

				; else, either song finished or
				; right pressed

plus_song:
	sei			; disable interrupts
	jsr	increment_file
	jmp	done_play

minus_song:
	sei			; disable interrupts
	jsr	decrement_file

done_play:

	lda	#0
	sta	DONE_PLAYING

	lda	#0
	sta	CH

	jsr	clear_bottoms

	jsr	new_song

	cli				; re-enable interrupts

	jmp	main_loop

forever_loop:
	jmp	forever_loop



	;=================
	; load a new song
	;=================

new_song:

	;=========================
	; Init Variables
	;=========================

	lda	#$0
	sta	FRAME_COUNT
	sta	A_VOLUME
	sta	B_VOLUME
	sta	C_VOLUME
	sta	COPY_OFFSET
	sta	DECOMPRESS_TIME
	sta	COPY_TIME
	sta	MB_CHUNK_OFFSET
	lda	#$20
	sta	DECODER_STATE
	lda	#3
	sta	CHUNKSIZE

	;===========================
	; Print loading message
	;===========================

	jsr	clear_bottoms		; clear bottom of page 0/1

	lda	#0			; print LOADING message
	sta	CH
	lda	#21
	sta	CV

	lda	#<loading_message
	sta	OUTL
	lda	#>loading_message
	sta	OUTH
        jsr     print_both_pages


	;===========================
	; Load in KRW file
	;===========================

	jsr	get_filename

	lda	#8
	sta	CH
	lda	#21
	sta	CV

	lda	INL
	sta	OUTL
	lda	INH
	sta	OUTH
	jsr	print_both_pages

disk_buff	EQU	LZ4_BUFFER
read_size	EQU	$4000

	jsr	read_file		; read KRW file from disk


	;=========================
	; Print Info
	;=========================

	jsr	clear_bottoms		; clear bottom of page 0/1

	lda	#>LZ4_BUFFER		; point to LZ4 data
	sta	OUTH
	lda	#<LZ4_BUFFER
	sta	OUTL

	ldy	#3			; skip KRW magic at front

	; print title
	lda	#20			; VTAB 20: HTAB from file
	jsr	print_header_info

	; Print Author
	lda	#21			; VTAB 21: HTAB from file
	jsr	print_header_info

	; Print clock
	lda	#23			; VTAB 23: HTAB from file
	jsr	print_header_info

	; Print Left Arrow (INVERSE)
	lda	#'<'
	sta	$750
	sta	$B50

	lda	#'-'
	sta	$751
	sta	$B51

	; Print Rright Arrow (INVERSE)
	lda	#'-'
	sta	$776
	sta	$B76

	lda	#'>'
	sta	$777
	sta	$B77





	; Point LZ4 src at proper place

	ldy	#0
	lda	#>(LZ4_BUFFER+3)
	sta	LZ4_SRC+1
	lda	#<(LZ4_BUFFER+3)
	sta	LZ4_SRC

	lda	(LZ4_SRC),Y		; get header skip
	clc
	adc	LZ4_SRC
	sta	LZ4_SRC
	lda	LZ4_SRC+1
	adc	#0
	sta	LZ4_SRC+1

	lda	#<UNPACK_BUFFER		; set input pointer
	sta	INL
	lda	#>UNPACK_BUFFER
	sta	INH

	; Decompress first chunks

	lda	#$0
	sta	COPY_OFFSET
	sta	DECOMPRESS_TIME
	lda	#$3
	sta	CHUNKSIZE
	lda	#$20
	sta	DECODER_STATE
	sta	COPY_TIME

	jsr	setup_next_subsong

	rts

	;=================
	; next sub-song
	;=================
setup_next_subsong:

	ldy	#0

	lda	(LZ4_SRC),Y		; get next size value
	sta	LZ4_END
	iny
	lda	(LZ4_SRC),Y
	sta	LZ4_END+1

	lda	#2			; increment pointer
	clc
	adc	LZ4_SRC
	sta	LZ4_SRC
	lda	LZ4_SRC+1
	adc	#0
	sta	LZ4_SRC+1

	jsr	lz4_decode		; decode

					; tail-call?

	rts



	;===================
	; print header info
	;===================
	; shortcut to print header info
	; a = VTAB

print_header_info:

	sta	CV

	iny				; adjust pointer
	tya
	ldy	#0
	clc
	adc	OUTL
	sta	OUTL
	lda	OUTH
	adc	#$0
	sta	OUTH

	lda	(OUTL),Y		; get HTAB value
	sta	CH

	inc	OUTL			; increment 16-bits
	bne	bloop22
	inc	OUTH
bloop22:

	jmp     print_both_pages	; print, tail call


	;==============================================
	; plan: takes 256  50Hz to play a chunk
	; need to copy 14 256-byte blocks
	; PLAY A (copying C)
	; PLAY B (copying C)
	; PLAY D (decompressing A/B/C)


	;========================
	; page copy
	;========================
	; want to copy:
	;	SRC: chunk_buffer+(2*256)+(COPY_OFFSET*3*256)
	;	DST: chunk_buffer+$2A00+(COPY_OFFSET*256)
page_copy:
	clc								; 2
	lda	#>(UNPACK_BUFFER+512)					; 3
	adc	COPY_OFFSET						; 3
	adc	COPY_OFFSET						; 3
	adc	COPY_OFFSET						; 3
	sta	page_copy_loop+2			; self modify	; 5

	lda	#>(UNPACK_BUFFER+$2A00)					; 2
	adc	COPY_OFFSET						; 3
	sta	page_copy_loop+5			; self modify	; 5

	ldx	#$00							; 2
page_copy_loop:
	lda	$1000,x							; 4
	sta	$1000,X							; 5
	inx								; 2
	bne	page_copy_loop						; 2nt/3
	rts								; 6
							;======================
							; 2+14*256+6+29= 3621


	;==================
	; Get filename
	;==================
	; WHICH_FILE holds number
	; MAX_FILES has max
	; Scroll through until find
	; point INH:INL to it
get_filename:

	ldy	#0
	ldx	WHICH_FILE

	lda	#<krw_file			; point to filename
	sta	INL
	lda	#>krw_file
	sta	INH

get_filename_loop:
	cpx	#0
	beq	filename_found

inner_loop:
	iny
	lda	(INL),Y
	bne	inner_loop

	iny

	dex
	jmp	get_filename_loop

filename_found:
	tya
	clc
	adc	INL
	sta	INL
	lda	INH
	adc	#0
	sta	INH

	rts

	;===============================
	; Increment file we want to load
	;===============================
increment_file:
	inc	WHICH_FILE
	lda	WHICH_FILE
	cmp	#NUM_FILES
	bne	done_increment
	lda	#0
	sta	WHICH_FILE
done_increment:
	rts

	;===============================
	; Decrement file we want to load
	;===============================
decrement_file:
	dec	WHICH_FILE
	bpl	done_decrement
	lda	#(NUM_FILES-1)
	sta	WHICH_FILE
done_decrement:
	rts

;==========
; filenames
;==========
krw_file:
	.asciiz "INTRO2.KRW"
	.asciiz "KORO.KRW"
	.asciiz "DEATH2.KRW"
	.asciiz "DEMO4.KRW"
	.asciiz "WAVE.KRW"
	.asciiz "SDEMO.KRW"
	.asciiz "SPUTNIK.KRW"
	.asciiz "ROBOT.KRW"
	.asciiz "LYRA2.KRW"
	.asciiz "KORO.KRW"
	.asciiz "INTRO2.KRW"
	.asciiz	"CRMOROS.KRW"
	.asciiz "CHRISTMAS.KRW"
	.asciiz "CAMOUFLAGE.KRW"
	.asciiz "FIGHTING.KRW"
	.asciiz "UNIVERSE.KRW"
	.asciiz "TECHNO.KRW"

;=========
;routines
;=========
.include	"../asm_routines/gr_offsets.s"
.include	"../asm_routines/text_print.s"
.include	"../asm_routines/mockingboard_a.s"
.include	"../asm_routines/gr_fast_clear.s"
.include	"../asm_routines/pageflip.s"
.include	"../asm_routines/gr_unrle.s"
.include	"../asm_routines/gr_setpage.s"
.include	"../asm_routines/dos33_routines.s"
.include	"../asm_routines/gr_hlin.s"
.include	"../asm_routines/lz4_decode.s"
.include	"../asm_routines/keypress_minimal.s"
.include	"rasterbars.s"
.include	"volume_bars.s"
.include	"interrupt_handler.s"

;=========
; strings
;=========
mocking_message:	.asciiz "LOOKING FOR MOCKINGBOARD IN SLOT #4"
not_message:		.byte   "NOT "
found_message:		.asciiz "FOUND"
;done_message:		.asciiz "DONE PLAYING"
loading_message:	.asciiz "LOADING"

;============
; graphics
;============
.include "chip_title.inc"