// tape.c
//
// 20060803 Markku Alén

#include "tape.h"
#include "cpu.h"
#include "mem.h"

#include "prg_file.h"

#define STATUS					(ram[0x90])
#define VERCKK					(ram[0x93])

#define EAL						(ram[0xae] | (ram[0xaf] << 8))

#define TBUFFR					(ram[0xb2] | (ram[0xb3] << 8))

#define FNLEN					(ram[0xb7])
#define FNADR					(ram[0xbb] | (ram[0xbc] << 8))

#define STAL					(ram[0xc1] | (ram[0xc2] << 8))

#define IRQTMP					(ram[0x2a0])

#define OFFSET_TYPE				0
#define OFFSET_START_ADDR		1
#define OFFSET_END_ADDR			3
#define OFFSET_NAME				5

#define TYPE_PRG				1	/* Binary Program */
#define TYPE_BAS				3	/* Relocatable Program */
#define TYPE_DATA				4	/* Data Record */
#define TYPE_EOF				5	/* End of Tape marker */

#define FIND_RET				0xF732
#define WRITE_RET				0xF7C1
#define TRANSFER_RET			0xFC93

#define WRITE_LEADER			0x0a
#define WRITE_BLOCK				0x08
#define READ_BLOCK				0x0e

#define EOF						0x40

static void copy_to_ram(int addr, int len, const void *buf)
{
	while(len-- > 0)
		ram[addr + len] = ((char *)buf)[len];
}

static void setup_tape_hdr(int type, const char *filename, int start_addr, int stop_addr)
{
	int i;
	char c, *p;
	p = &ram[TBUFFR];
	for(i = 0;i < 16;i++)
	{
		c = *filename;
		if(c != '\0')
			filename++;
		p[OFFSET_NAME + i] = c;
	}
	p[OFFSET_TYPE] = type;
	p[OFFSET_START_ADDR + 0] = start_addr % 256;
	p[OFFSET_START_ADDR + 1] = start_addr / 256;
	p[OFFSET_END_ADDR + 0] = stop_addr % 256;
	p[OFFSET_END_ADDR + 1] = stop_addr / 256;
}

static char filename[15 + 1];

static void get_filename(void)
{
	int i;
	char c, *p;
	p = &ram[FNADR];
	for(i = 0;i < (sizeof(filename) - 1);i++)
	{
		c = *(p++);
		if(c < '0' || c > '9')
		{
			if(c < 'A' || c > 'Z')
			{
				if(c < 'a' || c > 'z')
				{
					if(c != '.' && c != '_')
						c = '.';
				}
			}
		}
		filename[i] = c;
	}
	if(i > FNLEN)
		i = FNLEN;
	filename[i] = '\0';
}

static int find_header(void)
{
	int err;
	err = 0;
	get_filename();
	if(prg_load(filename) != 0)
		err = -1;
	if(err == 0)
		setup_tape_hdr(TYPE_BAS, filename, prg_addr, prg_addr + prg_len);
	STATUS = 0x00;
	VERCKK = 0x00;
	IRQTMP = 0x00;
	set_c_flag(err != 0);
	set_z_flag(0);
	set_pc(FIND_RET);
	return 0;
}

static int write_header(void)
{
	int i;
	i=0;
}

static int tape_transfer(void)
{
	int i;
	int err;
	int start, end, len;
	int st;
	err = 0;
	start = STAL;
	end = EAL;
	len = end - start;
	st = 0x00;
	switch(get_x())
	{
	case WRITE_LEADER:
		break;
	case WRITE_BLOCK:
//      if (fwrite(ram + start, len, 1, tape->FileDs) == 1) {
//	  st |= 0x40;		/* EOF */
//      }
//      else {
//	  st |= 0xB4;		/* All possible errors... */
//
//	  fprintf(stderr, "Error: Tape write failed.\n");
//      }
//      break;
		i=0;
	case READ_BLOCK:
		copy_to_ram(start, len, prg_data);
		st |= EOF;
		break;
	default:
		err = -1;
	}
	IRQTMP = 0x00;
	STATUS |= st;
	set_c_flag(err != 0);
	set_pc(TRANSFER_RET);
	return 0;
}

static trap_t traps[] =
{
	TRAP_INIT(0xF72F, 0x20, 0x41, 0xF8, &find_header), 
	TRAP_INIT(0xF7BE, 0x20, 0x6B, 0xF8, &write_header), 
	TRAP_INIT(0xF8A1, 0x20, 0xBD, 0xFC, &tape_transfer), 
};

void init_tape(void)
{
	install_traps(sizeof(traps) / sizeof(traps[0]), traps, &poke, &peek);
}