/* ----------------------------------------------------------------------- *
 *
 *   Copyright 2004-2008 H. Peter Anvin - All Rights Reserved
 *
 *   Permission is hereby granted, free of charge, to any person
 *   obtaining a copy of this software and associated documentation
 *   files (the "Software"), to deal in the Software without
 *   restriction, including without limitation the rights to use,
 *   copy, modify, merge, publish, distribute, sublicense, and/or
 *   sell copies of the Software, and to permit persons to whom
 *   the Software is furnished to do so, subject to the following
 *   conditions:
 *
 *   The above copyright notice and this permission notice shall
 *   be included in all copies or substantial portions of the Software.
 *
 *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
 *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
 *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
 *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 *   OTHER DEALINGS IN THE SOFTWARE.
 *
 * ----------------------------------------------------------------------- */

/*
 * ansicon_write.c
 *
 * Write to the screen using ANSI control codes (about as capable as
 * DOS' ANSI.SYS.)
 */

#include <errno.h>
#include <string.h>
#include <com32.h>
#include <minmax.h>
#include <colortbl.h>
#include <klibc/compiler.h>
#include "file.h"
#include "ansi.h"

static void ansicon_erase(const struct term_state *, int, int, int, int);
static void ansicon_write_char(int, int, uint8_t, const struct term_state *);
static void ansicon_showcursor(const struct term_state *);
static void ansicon_scroll_up(const struct term_state *);
static void ansicon_set_cursor(int, int, int);

static struct term_state ts;
struct ansi_ops __ansicon_ops = {
  .erase	= ansicon_erase,
  .write_char	= ansicon_write_char,
  .showcursor   = ansicon_showcursor,
  .set_cursor   = ansicon_set_cursor,
  .scroll_up    = ansicon_scroll_up,
};

static struct term_info ti =
  {
    .disabled = 0,
    .ts = &ts,
    .op = &__ansicon_ops
  };

#define BIOS_CURXY ((struct curxy *)0x450) /* Array for each page */
#define BIOS_ROWS (*(uint8_t *)0x484)      /* Minus one; if zero use 24 (= 25 lines) */
#define BIOS_COLS (*(uint16_t *)0x44A)
#define BIOS_PAGE (*(uint8_t *)0x462)

/* Reference counter to the screen, to keep track of if we need
   reinitialization. */
static int ansicon_counter = 0;

static uint16_t cursor_type;	/* Saved cursor pattern */

/* Common setup */
int __ansicon_open(struct file_info *fp)
{
  static com32sys_t ireg;	/* Auto-initalized to all zero */
  com32sys_t oreg;

  if (!ansicon_counter) {
    /* Are we disabled? */
    ireg.eax.w[0] = 0x000b;
    __intcall(0x22, &ireg, &oreg);

    if ( (signed char)oreg.ebx.b[1] < 0 ) {
      ti.disabled = 1;
    } else {
      /* Force text mode */
      ireg.eax.w[0] = 0x0005;
      __intcall(0x22, &ireg, NULL);

      /* Initial state */
      ti.rows = BIOS_ROWS ? BIOS_ROWS+1 : 25;
      ti.cols = BIOS_COLS;
      __ansi_init(&ti);

      /* Get cursor shape and position */
      ireg.eax.b[1] = 0x03;
      ireg.ebx.b[1] = BIOS_PAGE;
      __intcall(0x10, &ireg, &oreg);
      cursor_type = oreg.ecx.w[0];
      ti.ts->xy.x = oreg.edx.b[0];
      ti.ts->xy.y = oreg.edx.b[1];
    }
  }

  fp->o.rows = ti.rows;
  fp->o.cols = ti.cols;

  ansicon_counter++;
  return 0;
}

int __ansicon_close(struct file_info *fp)
{
  (void)fp;

  ansicon_counter--;
  return 0;
}

/* Turn ANSI attributes into VGA attributes */
static uint8_t ansicon_attribute(const struct term_state *st)
{
  int bg = st->bg;
  int fg;

  if ( st->underline )
    fg = 0x01;
  else if ( st->intensity == 0 )
    fg = 0x08;
  else
    fg = st->fg;

  if ( st->reverse ) {
    bg = fg & 0x07;
    fg &= 0x08;
    fg |= st->bg;
  }

  if ( st->blink )
    bg ^= 0x08;

  if ( st->intensity == 2 )
    fg ^= 0x08;

  return (bg << 4) | fg;
}

/* Erase a region of the screen */
static void ansicon_erase(const struct term_state *st,
			  int x0, int y0, int x1, int y1)
{
  static com32sys_t ireg;

  ireg.eax.w[0] = 0x0600;	/* Clear window */
  ireg.ebx.b[1] = ansicon_attribute(st);
  ireg.ecx.b[0] = x0;
  ireg.ecx.b[1] = y0;
  ireg.edx.b[0] = x1;
  ireg.edx.b[1] = y1;
  __intcall(0x10, &ireg, NULL);
}

/* Show or hide the cursor */
static void ansicon_showcursor(const struct term_state *st)
{
  static com32sys_t ireg;

  ireg.eax.b[1] = 0x01;
  ireg.ecx.w[0] = st->cursor ? cursor_type : 0x2020;
  __intcall(0x10, &ireg, NULL);
}

static void ansicon_set_cursor(int x, int y, int visible)
{
  const int page  = BIOS_PAGE;
  struct curxy xy = BIOS_CURXY[page];
  static com32sys_t ireg;

  (void)visible;

  if (xy.x != x || xy.y != y) {
    ireg.eax.b[1] = 0x02;
    ireg.ebx.b[1] = page;
    ireg.edx.b[1] = y;
    ireg.edx.b[0] = x;
    __intcall(0x10, &ireg, NULL);
  }
}

static void ansicon_write_char(int x, int y, uint8_t ch,
			       const struct term_state *st)
{
  static com32sys_t ireg;

  ansicon_set_cursor(x, y, 0);

  ireg.eax.b[1] = 0x09;
  ireg.eax.b[0] = ch;
  ireg.ebx.b[1] = BIOS_PAGE;
  ireg.ebx.b[0] = ansicon_attribute(st);
  ireg.ecx.w[0] = 1;
  __intcall(0x10, &ireg, NULL);
}

static void ansicon_scroll_up(const struct term_state *st)
{
  static com32sys_t ireg;

  ireg.eax.w[0] = 0x0601;
  ireg.ebx.b[1] = ansicon_attribute(st);
  ireg.ecx.w[0] = 0;
  ireg.edx.b[1] = ti.rows-1;
  ireg.edx.b[0] = ti.cols-1;
  __intcall(0x10, &ireg, NULL); /* Scroll */
}

ssize_t __ansicon_write(struct file_info *fp, const void *buf, size_t count)
{
  const unsigned char *bufp = buf;
  size_t n = 0;

  (void)fp;

  if ( ti.disabled )
    return n;			/* Nothing to do */

  while ( count-- ) {
    __ansi_putchar(&ti, *bufp++);
    n++;
  }

  return n;
}

const struct output_dev dev_ansicon_w = {
  .dev_magic  = __DEV_MAGIC,
  .flags      = __DEV_TTY | __DEV_OUTPUT,
  .fileflags  = O_WRONLY | O_CREAT | O_TRUNC | O_APPEND,
  .write      = __ansicon_write,
  .close      = __ansicon_close,
  .open       = __ansicon_open,
};
