#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include "vga_controller.h"
#include "io.h"
#include "sys/alt_alarm.h"
#include "sys/alt_cache.h"
#include "system.h"
#include "priv/alt_file.h"

// VGA device list (usualy just one)
ALT_LLIST_HEAD(vga_dev_list);

// General use buffer.  Must only use locally
char fast_buffer[1024 * 3];

/******************************************************************
*  Function: vga_dev_init
*
*  Purpose: HAL device driver initialization.  
*           Called by alt_sys_init.
*
******************************************************************/
int vga_dev_init ( vga_controller_dev* vga )
{
  int ret_code = 0;
 
  ret_code = vga_device_register( &(vga->dev) );
 
  return ret_code;
}

/******************************************************************
*  Function: alt_vga_open_dev
*
*  Purpose: Opens the VGA controller for use.  
*           Returns a file descriptor for the controller
*
******************************************************************/
alt_dev* alt_vga_open_dev(const char* name)
{
  alt_dev* dev = (alt_dev*)alt_find_dev(name, &vga_dev_list);

  return dev;
}

/******************************************************************
*  Function: alt_vga_close_dev
*
*  Purpose: Closes the VGA controller.
*
******************************************************************/
void alt_vga_close_dev(alt_dev* fd)
{
  return;
}

/******************************************************************
*  Function: vga_init_no_interrupt
*
*  Purpose: Initializes the VGA controller for the Lancelot VGA
*           daughterboard.  Gets memory for the frame buffer, sets 
*           the resolution of the frame buffer, resets the VGA 
*           controller hardware, gives the controller the base 
*           address of the frame buffer, then enables
*           the controller.  Interrupts are NOT enabled.
*
******************************************************************/
vga_frame_buffer_struct* vga_init_no_interrupt ( vga_controller_dev* vga, int buffer_location)
{
	vga_frame_buffer_struct* vga_frame_buffer;
  int bytes_per_pixel, bytes_per_frame;
  
  // We'll need these values more than once, so let's pre-calculate them.
  bytes_per_pixel = vga->color_depth >> 3;
  bytes_per_frame = (( vga->width * vga->height ) * bytes_per_pixel);

	// Allocate our frame buffers
	if( buffer_location == HEAP )
	{
		vga_frame_buffer = (vga_frame_buffer_struct*) alt_uncached_malloc(sizeof (vga_frame_buffer_struct));
	  vga_frame_buffer->vga_frame0 = (vga_frame_array*) alt_uncached_malloc(( bytes_per_frame ));
	  // If we're double-buffering, grab an extra buffer, if not, just make 
	  // both pointers point to the same buffer.
	  if(vga->frame_buffers == 2)
	  {
	  	vga_frame_buffer->vga_frame1 = (vga_frame_array*) alt_uncached_malloc(( bytes_per_frame ));
	  }
	  else
	  {
	  	vga_frame_buffer->vga_frame1 = vga_frame_buffer->vga_frame0;
	  }
	}
	else
	{
		vga_frame_buffer = (vga_frame_buffer_struct*)buffer_location;
		vga_frame_buffer->vga_frame0 = (vga_frame_array*)(buffer_location + sizeof(vga_frame_buffer_struct));
	  // If we're double-buffering, grab an extra buffer, if not, just make 
	  // both pointers point to the same buffer.
	  if(vga->frame_buffers == 2)
	  {
	  	vga_frame_buffer->vga_frame1 = (vga_frame_buffer->vga_frame0 + bytes_per_frame);
	  }
 	  else
	  {
	  	vga_frame_buffer->vga_frame1 = vga_frame_buffer->vga_frame0;
	  }
	}
	vga_frame_buffer->width = vga->width;
	vga_frame_buffer->height = vga->height;
	vga_frame_buffer->color_depth = vga->color_depth;
	vga_frame_buffer->frame_buffers = vga->frame_buffers;
	vga_frame_buffer->bytes_per_frame = bytes_per_frame;
	vga_frame_buffer->bytes_per_pixel = (vga->color_depth / 8);
	vga_frame_buffer->vga_controller_base = vga->base_addr;
	
  //Clear all frame buffers to black
	vga_clear_screen( vga_frame_buffer, BLACK_8 );
  vga_flip_frame_buffers( vga_frame_buffer );
	vga_clear_screen( vga_frame_buffer, BLACK_8 );
  	
	IOWR_32DIRECT( vga->base_addr, 0, 0x0 ); /* Reset the VGA controller */
	IOWR_32DIRECT( vga->base_addr, 4, ( int )vga_frame_buffer->vga_frame0 ); /* Where our frame buffer starts */
	IOWR_32DIRECT( vga->base_addr, 8, ( ( vga->width * vga->height ) * bytes_per_pixel ) ); /* amount of memory needed */   
	IOWR_32DIRECT( vga->base_addr, 0, 0x1 ); /* Set the go bit. */
	
  return ( vga_frame_buffer );
}

int vga_flip_frame_buffers( vga_frame_buffer_struct* vga_frame_buffer )
{
	vga_frame_array* temp_frame;
	int ret_code;
	
	if( vga_frame_buffer->frame_buffers == 2 )
	{
		temp_frame = vga_frame_buffer->vga_frame0;
		vga_frame_buffer->vga_frame0 = vga_frame_buffer->vga_frame1;
		vga_frame_buffer->vga_frame1 = temp_frame;
		IOWR_32DIRECT( vga_frame_buffer->vga_controller_base, 4, ( int )vga_frame_buffer->vga_frame0 );
		ret_code = 0;
	}
	else
	{
		ret_code = 1;
	}
	return(ret_code);
}

int vga_stop ( vga_controller_dev* vga )
{

	IOWR_32DIRECT( vga->base_addr, 0, 0x0 ); /* Reset the VGA controller */

  return (0);
}

void vga_scroll_string_quit(vga_text_scroll_struct* scroll)
{
  free(scroll->string);
  free(scroll);
}

vga_text_scroll_struct* vga_scroll_string_init(int hbegin, int vbegin, int hend, int f_color, int b_color, char* font, int ms_delay, char *string)
{
  vga_text_scroll_struct* scroll;
  scroll = malloc(sizeof (vga_text_scroll_struct));
  
  scroll->hbegin = hbegin;
  scroll->vbegin = vbegin;
  scroll->hend = hend;
  scroll->f_color = f_color;
  scroll->b_color = b_color;
  scroll->string = malloc(strlen(string)+2);
  strcpy(scroll->string, string);
  scroll->font = font;
  scroll->ms_delay = ms_delay;
  scroll->ticks_at_last_move = alt_nticks();
  scroll->text_scroll_index = 0;
  scroll->text_scroll_started = 0;
  scroll->window_width = scroll->hend - scroll->hbegin;
  scroll->length_of_string = strlen(string);
  scroll->string_points = scroll->length_of_string * 8;
  scroll->scroll_points = (scroll->window_width + scroll->string_points);
 
  return(scroll);
  
}


int vga_scroll_string(vga_text_scroll_struct* scroll, vga_frame_buffer_struct* vga_frame_buffer)
{

  int x_start, x_end, x_index, string_x_index, string_char_index, char_row, char_column;
  char character, column_mask;
  char* font_char_ptr;
  char pixels_to_move_by = 1;

  // If it's time to move the scroll..
  if (alt_nticks() >= (scroll->ticks_at_last_move + ((alt_ticks_per_second() * (scroll->ms_delay)) / 1000))) {
    scroll->ticks_at_last_move = alt_nticks();
    
    // Track where we are in the scroll.
    if(scroll->text_scroll_started == 0) {
      scroll->text_scroll_index = 0;
      scroll->text_scroll_started = 1;
    } else if(scroll->text_scroll_index >= scroll->scroll_points)  {
      scroll->text_scroll_started = 0;
    } else {
      scroll->text_scroll_index += pixels_to_move_by;
    }
    
    //Find out where we start
    if (scroll->text_scroll_index < scroll->window_width) {
      x_start = scroll->hbegin + scroll->window_width - scroll->text_scroll_index;
    } else {
      x_start = scroll->hbegin;
    }
    //Find out where we end
    if (scroll->string_points > scroll->text_scroll_index) {
      x_end = scroll->hend;
    } else {
      x_end = (scroll->hend - scroll->text_scroll_index + scroll->string_points);
    }

    // Write the string segment a column (x) at a time
    for(x_index = x_start; x_index < x_end; x_index++) {
      // Find the x index we're at within the string
      // If first part of string hasnt yet reached left side of scroll window
      if (scroll->text_scroll_index < scroll->window_width) {
        string_x_index = (x_index - x_start);
      } else {
        string_x_index = scroll->text_scroll_index - scroll->window_width + x_index - x_start;
      }
      //Find the character we're supposed to be writing
      string_char_index = (string_x_index / 8);
      character = scroll->string[string_char_index];
      char_column = (string_x_index % 8);
      column_mask = (((unsigned int)0x80) >> char_column);
      font_char_ptr = (scroll->font + ((character - 0x20) * FONT_10PT_ROW));
      //We have all the data now, so let's write a column
      for(char_row = 0; char_row < 11; char_row++) {
        // If the font table says this pixel is on, then set it to the foreground color
        if (*(font_char_ptr + char_row) & column_mask) {
          vga_set_pixel(x_index, scroll->vbegin + char_row, scroll->f_color, vga_frame_buffer); 
        // Otherwise, set it to the background color.
        } else {
          vga_set_pixel(x_index, scroll->vbegin + char_row, scroll->b_color, vga_frame_buffer); //background color
        }
      }
    }
    // Erase the leftover column (x) of the last string we wrote.
    vga_draw_line(x_end, scroll->vbegin, x_end, scroll->vbegin + 10, 1, scroll->b_color, vga_frame_buffer);
    // Log what time we moved the scroll.
  }
  return(0);
}


/******************************************************************
*  Function: vga_move_block
*
*  Purpose: Moves a block around the screen, backfilling with 
*           the backfill_color parameter.
*
******************************************************************/

int vga_move_block(int xbegin, int ybegin, int xend, int yend, int x_distance, int y_distance, int backfill_color, vga_frame_buffer_struct* vga_frame_buffer)
{
  int read_x, read_y, write_x, write_y;
  short temp_pixel;
  
  if(x_distance <= 0 && y_distance <= 0) {  
    //Move by rows because they are contiguous in memory (could help speed if in SDRAM)
    for (read_y = ybegin; read_y < yend; read_y++) {
      write_y = read_y + y_distance;
      for(read_x = xbegin; read_x < xend; read_x++) {
        write_x = read_x + x_distance;
        temp_pixel = vga_get_pixel(read_x, read_y, vga_frame_buffer);
        vga_set_pixel(write_x, write_y, temp_pixel, vga_frame_buffer);
        if(read_x >= xend + x_distance || read_y >= yend + y_distance) 
        {
	        vga_set_pixel(read_x, read_y, backfill_color, vga_frame_buffer);
        }
      }
    }
  }
  return (0);
}

/******************************************************************
*  Function: vga_print_string
*
*  Purpose: Prints a string to the specified location of the screen
*           using the specified font and color.
*           Calls vga_print_char
*
******************************************************************/
int vga_print_string(int horiz_offset, int vert_offset, int color, char *font, vga_frame_buffer_struct* vga_frame_buffer, char string[])
{
  int i = 0;
  int original_horiz_offset;

  original_horiz_offset = horiz_offset;

  // Print until we hit the '\0' char.
  while (string[i]) {
    //Handle newline char here.
    if (string[i] == '\n') {
      horiz_offset = original_horiz_offset;
      vert_offset += 12;
      i++;
      continue;
    }
    // Lay down that character and increment our offsets.
    vga_print_char (horiz_offset, vert_offset, color, string[i], font, vga_frame_buffer);
    i++;
    horiz_offset += 8;
  }
  return (0);
}

/******************************************************************