/*++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                              console.c
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
                                                    Forrest Yu, 2005
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++*/

/*
	回車鍵:	把光標移到第一列
	換行鍵:	把光標前進到下一行
*/


#include "type.h"
#include "const.h"
#include "protect.h"
#include "string.h"
#include "proc.h"
#include "tty.h"
#include "console.h"
#include "global.h"
#include "keyboard.h"
#include "proto.h"


/* 本文件內函數聲明 */
PRIVATE void	set_cursor(unsigned int position);
PRIVATE void	set_video_start_addr(t_32 addr);
PRIVATE void	flush(CONSOLE* p_con);


/*======================================================================*
                           init_screen
 *======================================================================*/
PUBLIC void init_screen(TTY* p_tty)
{
	int nr_tty = p_tty - tty_table;
	p_tty->p_console = console_table + nr_tty;

	int v_mem_size = V_MEM_SIZE >> 1;	/* 顯存總大小 (in WORD) */

	int con_v_mem_size			= v_mem_size / NR_CONSOLES;		/* 每個控制臺占的顯存大小		(in WORD) */
	p_tty->p_console->original_addr		= nr_tty * con_v_mem_size;		/* 當前控制臺占的顯存開始地址		(in WORD) */
	p_tty->p_console->v_mem_limit		= con_v_mem_size / SCREEN_WIDTH * SCREEN_WIDTH;			/* 當前控制臺占的顯存大小		(in WORD) */
	p_tty->p_console->current_start_addr	= p_tty->p_console->original_addr;	/* 當前控制臺顯示到了顯存的什么位置	(in WORD) */

	p_tty->p_console->cursor = p_tty->p_console->original_addr;	/* 默認光標位置在最開始處 */

	if (nr_tty == 0) {
		p_tty->p_console->cursor = disp_pos / 2;	/* 第一個控制臺延用原來的光標位置 */
		disp_pos = 0;
	}
	else {
		out_char(p_tty->p_console, nr_tty + '0');
		out_char(p_tty->p_console, '#');
	}

	set_cursor(p_tty->p_console->cursor);
}


/*======================================================================*
                           out_char
 *======================================================================*/
PUBLIC void out_char(CONSOLE* p_con, char ch)
{
	t_8* p_vmem = (t_8*)(V_MEM_BASE + p_con->cursor * 2);

	switch(ch) {
	case '\n':
		if (p_con->cursor < p_con->original_addr + p_con->v_mem_limit - SCREEN_WIDTH) {
			p_con->cursor = p_con->original_addr + SCREEN_WIDTH * ((p_con->cursor - p_con->original_addr) / SCREEN_WIDTH + 1);
		}
		break;
	case '\b':
		if (p_con->cursor > p_con->original_addr) {
			p_con->cursor--;
			*(p_vmem-2) = ' ';
			*(p_vmem-1) = DEFAULT_CHAR_COLOR;
		}
		break;
	default:
		if (p_con->cursor < p_con->original_addr + p_con->v_mem_limit - 1) {
			*p_vmem++ = ch;
			*p_vmem++ = DEFAULT_CHAR_COLOR;
			p_con->cursor++;
		}
		break;
	}

	while (p_con->cursor >= p_con->current_start_addr + SCREEN_SIZE) {
		scroll_screen(p_con, SCROLL_SCREEN_DOWN);
	}

	flush(p_con);
}


/*======================================================================*
                           is_current_console
 *======================================================================*/
PUBLIC t_bool is_current_console(CONSOLE* p_con)
{
	return (p_con == &console_table[nr_current_console]);
}


/*======================================================================*
                            set_cursor
 *======================================================================*/
PRIVATE void set_cursor(unsigned int position)
{
	disable_int();
	out_byte(CRTC_ADDR_REG, CRTC_DATA_IDX_CURSOR_H);
	out_byte(CRTC_DATA_REG, (position >> 8) & 0xFF);
	out_byte(CRTC_ADDR_REG, CRTC_DATA_IDX_CURSOR_L);
	out_byte(CRTC_DATA_REG, position & 0xFF);
	enable_int();
}


/*======================================================================*
                          set_video_start_addr
 *======================================================================*/
PRIVATE void set_video_start_addr(t_32 addr)
{
	disable_int();
	out_byte(CRTC_ADDR_REG, CRTC_DATA_IDX_START_ADDR_H);
	out_byte(CRTC_DATA_REG, (addr >> 8) & 0xFF);
	out_byte(CRTC_ADDR_REG, CRTC_DATA_IDX_START_ADDR_L);
	out_byte(CRTC_DATA_REG, addr & 0xFF);
	enable_int();
}


/*======================================================================*
                           select_console
 *======================================================================*/
PUBLIC void select_console(int nr_console)	/* 0 ~ (NR_CONSOLES - 1) */
{
	if ((nr_console < 0) || (nr_console >= NR_CONSOLES)) {	/* invalid console number */
		return;
	}

	nr_current_console = nr_console;

	flush(&console_table[nr_console]);
}


/*======================================================================*
                           scroll_screen
 *----------------------------------------------------------------------*
 滾屏.
 *----------------------------------------------------------------------*
 direction:
	SCROLL_SCREEN_UP	: 向上滾屏
	SCROLL_SCREEN_DOWN	: 向下滾屏
	其它			: 不做處理
 *======================================================================*/
PUBLIC void scroll_screen(CONSOLE* p_con, int direction)
{
	if (direction == SCROLL_SCREEN_UP) {
		if (p_con->current_start_addr > p_con->original_addr) {
			p_con->current_start_addr -= SCREEN_WIDTH;
		}
	}
	else if (direction == SCROLL_SCREEN_DOWN) {
		if (p_con->current_start_addr + SCREEN_SIZE < p_con->original_addr + p_con->v_mem_limit) {
			p_con->current_start_addr += SCREEN_WIDTH;
		}
	}
	else{
	}

	flush(p_con);
}


/*======================================================================*
                           flush
*======================================================================*/
PRIVATE void flush(CONSOLE* p_con)
{
	if (is_current_console(p_con)) {
		set_cursor(p_con->cursor);
		set_video_start_addr(p_con->current_start_addr);
	}
}