/*

 * Copyright © 2012  Google, Inc.

 *

 *  This is part of HarfBuzz, a text shaping library.

 *

 * Permission is hereby granted, without written agreement and without

 * license or royalty fees, to use, copy, modify, and distribute this

 * software and its documentation for any purpose, provided that the

 * above copyright notice and the following two paragraphs appear in

 * all copies of this software.

 *

 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR

 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES

 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN

 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH

 * DAMAGE.

 *

 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,

 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS

 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO

 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 *

 * Google Author(s): Behdad Esfahbod

 */

#ifdef HAVE_CONFIG_H

#include "config.h"

#endif

#include "ansi-print.hh"

#include <assert.h>

#include <stdlib.h>

#include <stddef.h>

#include <string.h>

#include <stdio.h>

#include <math.h>

#include <fcntl.h>

#ifdef HAVE_UNISTD_H

#include <unistd.h> /* for isatty() */

#endif

#if defined (_MSC_VER) && (_MSC_VER < 1800)

static inline long int

lround (double x)

{

  if (x >= 0)

    return floor (x + 0.5);

  else

    return ceil (x - 0.5);

}

#endif

#define ESC_E (char)27

#define MIN(a,b) ((a) < (b) ? (a) : (b))

#define CELL_W 8

#define CELL_H (2 * CELL_W)

struct color_diff_t

{

  int dot (const color_diff_t &o)

  { return v[0]*o.v[0] + v[1]*o.v[1] + v[2]*o.v[2] + v[3]*o.v[3]; }

  int v[4];

};

struct color_t

{

  static color_t from_ansi (unsigned int x)

  {

    color_t c = {(0xFF<<24) | ((0xFF*(x&1))<<16) | ((0xFF*((x >> 1)&1))<<8) | (0xFF*((x >> 2)&1))};

    return c;

  }

  unsigned int to_ansi (void)

  {

    return ((v >> 23) & 1) | ((v >> 14)&2) | ((v >> 5)&4;;

  }

  color_diff_t diff (const color_t &o)

  {

    color_diff_t d;

    for (unsigned int i = 0; i < 4; i++)

      d.v[i] = (int) ((v >> (i*8))&0xFF) - (int) ((o.v >> (i*8))&0xFF);

    return d;

  }

  uint32_t v;

};

struct image_t

{

  public:

  image_t (unsigned int width_,

	   unsigned int height_,

	   const uint32_t *data_,

	   unsigned int stride_) :

		width (width_),

		height (height_),

		own_data (false),

		data ((color_t *) data_),

		stride (stride_) {}

  image_t (unsigned int width_,

	   unsigned int height_) :

		width (width_),

		height (height_),

		own_data (true),

		data ((color_t *) malloc (sizeof (data[0]) * width * height)),

		stride (width) {}

  ~image_t (void)

  { if (own_data) free (data); }

  color_t &operator () (unsigned int x, unsigned int y)

  { return data[x + y * stride]; }

  color_t operator () (unsigned int x, unsigned int y) const

  { return data[x + y * stride]; }

  void

  copy_sub_image (const image_t &s,

		  unsigned int x, unsigned int y,

		  unsigned int w, unsigned int h)

  {

    assert (x < width);

    assert (y < height);

    for (unsigned int row = 0; row < h; row++) {

      color_t *p = data + x + MIN (y + row, height - 1) * stride;

      color_t *q = s.data + row * s.stride;

      if (x + w <= width)

	for (unsigned int col = 0; col < w; col++)

	  *q++ = *p++;

      else {

        unsigned int limit = width - x;

	for (unsigned int col = 0; col < limit; col++)

	  *q++ = *p++;

	p--;

	for (unsigned int col = limit; col < w; col++)

	  *q++ = *p;

      }

    }

  }

  const unsigned int width;

  const unsigned int height;

  private:

  bool own_data;

  color_t * const data;

  const unsigned int stride;

};

struct biimage_t

{

  public:

  biimage_t (unsigned int width, unsigned int height) :

		width (width),

		height (height),

		bg (0), fg (0), unicolor (true),

		data ((uint8_t *) malloc (sizeof (data[0]) * width * height)) {}

  ~biimage_t (void)

  { free (data); }

  void set (const image_t &image)

  {

    assert (image.width == width);

    assert (image.height == height);

    int freq[8] = {0};

    for (unsigned int y = 0; y < height; y++)

      for (unsigned int x = 0; x < width; x++) {

        color_t c = image (x, y);

        freq[c.to_ansi ()]++;

      }

    bg = 0;

    for (unsigned int i = 1; i < 8; i++)

      if (freq[bg] < freq[i])

        bg = i;

    fg = 0;

    for (unsigned int i = 1; i < 8; i++)

      if (i != bg && freq[fg] < freq[i])

        fg = i;

    if (fg == bg || freq[fg] == 0) {

      fg = bg;

      unicolor = true;

    }

    else

      unicolor = false;

    /* Set the data... */

    if (unicolor) {

      memset (data, 0, sizeof (data[0]) * width * height);

      return;

    }

    color_t bgc = color_t::from_ansi (bg);

    color_t fgc = color_t::from_ansi (fg);

    color_diff_t diff = fgc.diff (bgc);

    int dd = diff.dot (diff);

    for (unsigned int y = 0; y < height; y++)

      for (unsigned int x = 0; x < width; x++) {

        int d = diff.dot (image (x, y).diff (bgc));

	(*this)(x, y) = d < 0 ? 0 : d > dd ? 255 : lround (d * 255. / dd);

      }

  }

  uint8_t &operator () (unsigned int x, unsigned int y)

  { return data[x + y * width]; }

  uint8_t operator () (unsigned int x, unsigned int y) const

  { return data[x + y * width]; }

  const unsigned int width;

  const unsigned int height;

  unsigned int bg;

  unsigned int fg;

  bool unicolor;

  private:

  uint8_t * const data;

};

const char *

block_best (const biimage_t &bi, bool *inverse)

{

  assert (bi.width  <= CELL_W);

  assert (bi.height <= CELL_H);

  unsigned int score = (unsigned int) -1;

  unsigned int row_sum[CELL_H] = {0};

  unsigned int col_sum[CELL_W] = {0};

  unsigned int row_sum_i[CELL_H] = {0};

  unsigned int col_sum_i[CELL_W] = {0};

  unsigned int quad[2][2] = {{0}};

  unsigned int quad_i[2][2] = {{0}};

  unsigned int total = 0;

  unsigned int total_i = 0;

  for (unsigned int y = 0; y < bi.height; y++)

    for (unsigned int x = 0; x < bi.width; x++) {

      unsigned int c = bi (x, y);

      unsigned int c_i = 255 - c;

      row_sum[y] += c;

      row_sum_i[y] += c_i;

      col_sum[x] += c;

      col_sum_i[x] += c_i;

      quad[2 * y / bi.height][2 * x / bi.width] += c;

      quad_i[2 * y / bi.height][2 * x / bi.width] += c_i;

      total += c;

      total_i += c_i;

    }

  /* Make the sums cummulative */

  for (unsigned int i = 1; i < bi.height; i++) {

    row_sum[i] += row_sum[i - 1];

    row_sum_i[i] += row_sum_i[i - 1];

  }

  for (unsigned int i = 1; i < bi.width;  i++) {

    col_sum[i] += col_sum[i - 1];

    col_sum_i[i] += col_sum_i[i - 1];

  }

  const char *best_c = " ";

  /* Maybe empty is better! */

  if (total < score) {

    score = total;

    *inverse = false;

    best_c = " ";

  }

  /* Maybe full is better! */

  if (total_i < score) {

    score = total_i;

    *inverse = true;

    best_c = " ";

  }

  /* Find best lower line */

  if (1) {

    unsigned int best_s = (unsigned int) -1;

    bool best_inv = false;

    int best_i = 0;

    for (unsigned int i = 0; i < bi.height - 1; i++)

    {

      unsigned int s;

      s = row_sum[i] + total_i - row_sum_i[i];

      if (s < best_s) {

        best_s = s;

	best_i = i;

	best_inv = false;

      }

      s = row_sum_i[i] + total - row_sum[i];

      if (s < best_s) {

        best_s = s;

	best_i = i;

	best_inv = true;

      }

    }

    if (best_s < score) {

      static const char *lower[7] = {"▁", "▂", "▃", "▄", "▅", "▆", "▇"};

      unsigned int which = lround ((double) ((best_i + 1) * 8) / bi.height);

      if (1 <= which && which <= 7) {

	score = best_s;

	*inverse = best_inv;

	best_c = lower[7 - which];

      }

    }

  }

  /* Find best left line */

  if (1) {

    unsigned int best_s = (unsigned int) -1;

    bool best_inv = false;

    int best_i = 0;

    for (unsigned int i = 0; i < bi.width - 1; i++)

    {

      unsigned int s;

      s = col_sum[i] + total_i - col_sum_i[i];

      if (s < best_s) {

        best_s = s;

	best_i = i;

	best_inv = true;

      }

      s = col_sum_i[i] + total - col_sum[i];

      if (s < best_s) {

        best_s = s;

	best_i = i;

	best_inv = false;

      }

    }

    if (best_s < score) {

      static const char *left [7] = {"▏", "▎", "▍", "▌", "▋", "▊", "▉"};

      unsigned int which = lround ((double) ((best_i + 1) * 8) / bi.width);

      if (1 <= which && which <= 7) {

	score = best_s;

	*inverse = best_inv;

	best_c = left[which - 1];

      }

    }

  }

  /* Find best quadrant */

  if (1) {

    unsigned int q = 0;

    unsigned int qs = 0;

    for (unsigned int i = 0; i < 2; i++)

      for (unsigned int j = 0; j < 2; j++)

	if (quad[i][j] > quad_i[i][j]) {

	  q += 1 << (2 * i + j);

	  qs += quad_i[i][j];

	} else

	  qs += quad[i][j];

    if (qs < score) {

      const char *c = NULL;

      bool inv = false;

      switch (q) {

	case 1:  c = "▟"; inv = true;  break;

	case 2:  c = "▙"; inv = true;  break;

	case 4:  c = "▖"; inv = false; break;

	case 8:  c = "▗"; inv = false; break;

	case 9:  c = "▚"; inv = false; break;

	case 6:  c = "▞"; inv = false; break;

	case 7:  c = "▜"; inv = true;  break;

	case 11: c = "▜"; inv = true;  break;

	case 13: c = "▙"; inv = true;  break;

	case 14: c = "▟"; inv = true;  break;

      }

      if (c) {

	score = qs;

	*inverse = inv;

	best_c = c;

      }

    }

  }

  return best_c;

}

void

ansi_print_image_rgb24 (const uint32_t *data,

			unsigned int width,

			unsigned int height,

			unsigned int stride)

{

  image_t image (width, height, data, stride);

  unsigned int rows = (height + CELL_H - 1) / CELL_H;

  unsigned int cols = (width +  CELL_W - 1) / CELL_W;

  image_t cell (CELL_W, CELL_H);

  biimage_t bi (CELL_W, CELL_H);

  unsigned int last_bg = -1, last_fg = -1;

  for (unsigned int row = 0; row < rows; row++) {

    for (unsigned int col = 0; col < cols; col++) {

      image.copy_sub_image (cell, col * CELL_W, row * CELL_H, CELL_W, CELL_H);

      bi.set (cell);

      if (bi.unicolor) {

        if (last_bg != bi.bg) {

	  printf ("%c[%dm", ESC_E, 40 + bi.bg);

	  last_bg = bi.bg;

	}

	printf (" ");

      } else {

        /* Figure out the closest character to the biimage */

	bool inverse = false;

        const char *c = block_best (bi, &inverse);

	if (inverse) {

	  if (last_bg != bi.fg || last_fg != bi.bg) {

	    printf ("%c[%d;%dm", ESC_E, 30 + bi.bg, 40 + bi.fg);

	    last_bg = bi.fg;

	    last_fg = bi.bg;

	  }

	} else {

	  if (last_bg != bi.bg || last_fg != bi.fg) {

	    printf ("%c[%d;%dm", ESC_E, 40 + bi.bg, 30 + bi.fg);

	    last_bg = bi.bg;

	    last_fg = bi.fg;

	  }

	}

	printf ("%s", c);

      }

    }

    printf ("%c[0m\n", ESC_E); /* Reset */

    last_bg = last_fg = -1;

  }

}