#include "factor.h"

void init_io(void)
{
	env.user[STDIN_ENV]  = port(0);
	env.user[STDOUT_ENV] = port(1);
	env.user[STDERR_ENV] = port(2);
}

int read_step(PORT* port)
{
	int amount = read(port->fd,
		port->buffer + 1,
		port->buffer->capacity * 2);

	port->buf_fill = (amount < 0 ? 0 : amount);
	port->buf_pos = 0;

	return amount;
}

READLINE_STAT read_line_step(PORT* port)
{
	int amount;
	int i;
	int ch;

	SBUF* line = port->line;

	if(port->buf_pos >= port->buf_fill)
	{
		amount = read_step(port);

		if(amount < 0)
			io_error(__FUNCTION__);
		else if(amount == 0)
			return READLINE_EOF;
	}

	for(i = port->buf_pos; i < port->buf_fill; i++)
	{
		ch = bget((CELL)port->buffer + sizeof(STRING) + i);
		if(ch == '\n')
		{
			port->buf_pos = i + 1;
			return READLINE_EOL;
		}
		else
			set_sbuf_nth(line,line->top,ch);
	}

	port->buf_pos = port->buf_fill;

	/* We've reached the end of the above loop, without seeing a newline
	or EOF, so read again */
	return READLINE_AGAIN;
}

void primitive_read_line_fd_8(void)
{
	PORT* port = untag_port(dpeek());
	SBUF* line;
	READLINE_STAT state;

	init_buffer(port,B_READ);
	if(port->line == NULL)
		port->line = sbuf(LINE_SIZE);
	else
		port->line->top = 0;
	line = port->line;

	for(;;)
	{
		state = read_line_step(port);
		if(state != READLINE_AGAIN)
		{
			if(state == READLINE_EOF && line->top == 0)
			{
				/* didn't read anything before EOF */
				drepl(F);
			}
			else
				drepl(tag_object(sbuf_to_string(line)));
			return;
		}
	}
}

void write_step(PORT* port)
{
	char* chars = (char*)port->buffer + sizeof(STRING);

	FIXNUM amount = write(port->fd,chars + port->buf_pos,
		port->buf_fill - port->buf_pos);

	if(amount < 0)
		io_error(__FUNCTION__);

	port->buf_pos += amount;
}

/* keep writing to the stream until everything is written */
void flush_buffer(PORT* port)
{
	if(port->buf_mode != B_WRITE || port->buf_fill == 0)
		return;

	for(;;)
	{
		if(port->buf_fill == port->buf_pos)
			break;

		write_step(port);
	}

	port->buf_pos = 0;
	port->buf_fill = 0;
}

void write_fd_char_8(PORT* port, FIXNUM ch)
{
	char c = (char)ch;

	init_buffer(port,B_WRITE);

	/* Is the buffer full? */
	if(port->buf_fill == port->buffer->capacity * CHARS)
		flush_buffer(port);

	bput((CELL)port->buffer + sizeof(STRING) + port->buf_fill,c);
	port->buf_fill++;
}

void write_fd_string_8(PORT* port, STRING* str)
{
	char* c_str = to_c_string(str);

	init_buffer(port,B_WRITE);

	/* Is the string longer than the buffer? */
	if(str->capacity > port->buffer->capacity * CHARS)
	{
		flush_buffer(port);

		/* Increase the buffer to fit the string */
		port->buffer = allot_string(str->capacity / CHARS + 1);
	}
	/* Is there enough room in the buffer? If not, flush */
	if(port->buf_fill + str->capacity
		> port->buffer->capacity * CHARS)
	{
		flush_buffer(port);
	}

	/* Append string to buffer */
	memcpy((void*)((CELL)port->buffer + sizeof(STRING)
		+ port->buf_fill),c_str,str->capacity);

	port->buf_fill += str->capacity;
}

void primitive_write_fd_8(void)
{
	PORT* port = untag_port(dpop());

	CELL text = dpop();
	CELL type = type_of(text);

	switch(type)
	{
	case FIXNUM_TYPE:
	case BIGNUM_TYPE:
		write_fd_char_8(port,to_fixnum(text));
		break;
	case STRING_TYPE:
		write_fd_string_8(port,untag_string(text));
		break;
	default:
		type_error(STRING_TYPE,text);
		break;
	}
}

void primitive_flush_fd(void)
{
	PORT* port = untag_port(dpop());
	flush_buffer(port);
}

void primitive_close_fd(void)
{
	PORT* port = untag_port(dpop());
	flush_buffer(port);
	close(port->fd);
}