/**
* Sutton SignWriting TrueType Font Module v1.6.0 (https://github.com/sutton-signwriting/font-ttf)
* Author: Steve Slevinski  (https://SteveSlevinski.me)
* font.mjs is released under the MIT License.
*/

/**
 * Function that appends font-face CSS for the Sutton SignWriting fonts for system installed fonts, relative directory fonts, or content delivery network
 * @function font.cssAppend
 * @param {string} dir - an optional relative directory for font location
 * @example
 * font.cssAppend('./font/')
 */
const cssAppend = function (dir = '') {
  const id = "SgnwFontCss";
  if (!document.getElementById(id)) {
    const style = document.createElement('style');
    style.setAttribute("id", "SgnwFontCss");
    style.appendChild(document.createTextNode(`
  @font-face {
    font-family: "SuttonSignWritingLine";
    src: 
      local('SuttonSignWritingLine'),
      ${dir ? `url('${dir}SuttonSignWritingLine.ttf') format('truetype'),` : ""}
      url('https://cdn.jsdelivr.net/npm/@sutton-signwriting/font-ttf@1.0.0/font/SuttonSignWritingLine.ttf') format('truetype');
  }
  @font-face {
    font-family: "SuttonSignWritingFill";
    src: 
      local('SuttonSignWritingFill'),
      ${dir ? `url('${dir}SuttonSignWritingFill.ttf') format('truetype'),` : ""}
      url('https://cdn.jsdelivr.net/npm/@sutton-signwriting/font-ttf@1.0.0/font/SuttonSignWritingFill.ttf') format('truetype');
  }
  @font-face {
    font-family: "SuttonSignWritingOneD";
    src: 
      local('SuttonSignWritingOneD'),
      ${dir ? `url('${dir}SuttonSignWritingOneD.ttf') format('truetype'),` : ""}
      url('https://cdn.jsdelivr.net/npm/@sutton-signwriting/font-ttf@1.0.0/font/SuttonSignWritingOneD.ttf') format('truetype');
  }
    `));
    document.head.appendChild(style);
  }
};

let sizes = {};
const zoom = 2;
const bound = 76 * zoom;
let context;

/**
 * Function that returns the size of a symbol using an id
 * @function font.symbolSize
 * @param {number} id - a 16-bit number of a symbol
 * @returns {number[]} width and height of symbol
 * @example
 * font.symbolSize(1)
 * 
 * return [15,30]
 */
const symbolSize = function (id) {
  if (id in sizes) {
    return [...sizes[id]];
  }
  if (!context) {
    const canvaser = document.createElement("canvas");
    canvaser.width = bound;
    canvaser.height = bound;
    context = canvaser.getContext("2d", {
      willReadFrequently: true
    });
  }
  context.clearRect(0, 0, bound, bound);
  context.font = 30 * zoom + "px 'SuttonSignWritingLine'";
  context.fillText(String.fromCodePoint(id + 0xF0000), 0, 0);
  const imgData = context.getImageData(0, 0, bound, bound).data;
  let w, h, i, s;
  wloop: for (w = bound - 1; w >= 0; w--) {
    for (h = 0; h < bound; h += 1) {
      for (s = 0; s < 4; s += 1) {
        i = w * 4 + h * 4 * bound + s;
        if (imgData[i]) {
          break wloop;
        }
      }
    }
  }
  var width = w;
  hloop: for (h = bound - 1; h >= 0; h--) {
    for (w = 0; w < width; w += 1) {
      for (s = 0; s < 4; s += 1) {
        i = w * 4 + h * 4 * bound + s;
        if (imgData[i]) {
          break hloop;
        }
      }
    }
  }
  var height = h + 1;
  width = Math.ceil(width / zoom);
  height = Math.ceil(height / zoom);
  // Rounding error in chrome.  Manual fixes.
  if (14394 == id) {
    width = 19;
  }
  if ([10468, 10480, 10496, 10512, 10500, 10532, 10548, 10862, 10878, 10894, 11058, 11074, 11476, 11488, 11492, 11504, 11508, 11520, 10516, 10910, 10926, 11042, 11082, 10942].includes(id)) {
    width = 20;
  }
  if (31921 == id) {
    width = 22;
  }
  if (38460 == id) {
    width = 23;
  }
  if ([20164, 20212].includes(id)) {
    width = 25;
  }
  if (31894 == id) {
    width = 28;
  }
  if (46698 == id) {
    width = 29;
  }
  if (29606 == id) {
    width = 30;
  }
  if (44855 == id) {
    width = 40;
  }
  if (32667 == id) {
    width = 50;
  }
  if ([11088, 11474, 11490, 11506].includes(id)) {
    height = 20;
  }
  if (6285 == id) {
    height = 21;
  }
  if (40804 == id) {
    height = 31;
  }
  if (41475 == id) {
    height = 36;
  }
  // Error in chrome.  Manual fix.
  // if (width==0 && height==0) {
  if (width == 0 && height == 0) {
    const sizefix = {
      9: [15, 30],
      10: [21, 30],
      11: [30, 15],
      12: [30, 21],
      13: [15, 30],
      14: [21, 30]
    };
    if (id in sizefix) {
      width = sizefix[id][0];
      height = sizefix[id][1];
    }
  }
  if (width == 0 && height == 0) {
    return undefined;
  }
  sizes[id] = [width, height];
  return [width, height];
};

/**
 * Function that returns a plane 15 character for a symbol line using an id
 * @function font.symbolLine
 * @param {number} id - a 16-bit number of a symbol
 * @returns {string} character for symbol line
 * @example
 * font.symbolLine(1)
 * 
 * return '󰀁'
 */
const symbolLine = function (id) {
  return String.fromCodePoint(id + 0xF0000);
};

/**
 * Function that returns a plane 16 character for a symbol fill using an id
 * @function font.symbolFill
 * @param {number} id - a 16-bit number of a symbol
 * @returns {string} character for symbol fill
 * @example
 * font.symbolFill(1)
 * 
 * return '􀀁'
 */
const symbolFill = function (id) {
  return String.fromCodePoint(id + 0x100000);
};

/**
 * Function that creates two text elements for a symbol using an id
 * @function font.symbolText
 * @param {number} id - a 16-bit number of a symbol
 * @returns {string} SVG segment for line and fill
 * @example
 * font.symbolText(1)
 * 
 * return `    <text class="sym-fill" fill="white" style="pointer-events:none;font-family:'SuttonSignWritingFill';font-size:30px;">􀀁</text>
 *     <text class="sym-line" fill="black" style="pointer-events:none;font-family:'SuttonSignWritingLine';font-size:30px;">󰀁</text>`
 */
const symbolText = function (id) {
  return `    <text class="sym-fill" fill="white" style="pointer-events:none;font-family:'SuttonSignWritingFill';font-size:30px;">${symbolFill(id)}</text>
    <text class="sym-line" fill="black" style="pointer-events:none;font-family:'SuttonSignWritingLine';font-size:30px;">${symbolLine(id)}</text>`;
};

/**
 * Function that executes a callback function once the Sutton SignWriiting Line and Fill fonts are ready to use
 * @function font.cssLoaded
 * @param {function} callback - a callback function to execute when fonts are ready
 * @example
 * const callback = () => {
 *   console.log("Sutton SignWriting Line and Fill fonts are ready to use")
 * }
 * 
 * font.cssLoaded( callback )
 */
const cssLoaded = function (callback) {
  let lineReady = false;
  let fillReady = false;
  cssLoadedLine(() => {
    lineReady = true;
  });
  cssLoadedFill(() => {
    fillReady = true;
  });
  const cssCheck = setInterval(function () {
    if (lineReady && fillReady) {
      clearInterval(cssCheck);
      callback();
    }
  }, 100);
};

/**
 * Function that executes a callback function once the Sutton SignWriiting Line font is ready to use
 * @function font.cssLoadedLine
 * @param {function} callback - a callback function to execute when line font is ready
 * @example
 * const callback = () => {
 *   console.log("Sutton SignWriting Line font is ready to use")
 * }
 * 
 * font.cssLoadedLine( callback )
 */
const cssLoadedLine = function (callback) {
  if (!symbolSize(1)) {
    const cssCheck = setInterval(function () {
      if (symbolSize(1)) {
        clearInterval(cssCheck);
        callback();
      }
    }, 100);
  } else {
    callback();
  }
};

/**
 * Function that executes a callback function once the Sutton SignWriiting Fill font is ready to use
 * @function font.cssLoadedFill
 * @param {function} callback - a callback function to execute when fill font is ready
 * @example
 * const callback = () => {
 *   console.log("Sutton SignWriting Fill font is ready to use")
 * }
 * 
 * font.cssLoadedFill( callback )
 */
const cssLoadedFill = function (callback) {
  const fillReady = function () {
    const canvaser = document.createElement("canvas");
    canvaser.width = 15;
    canvaser.height = 30;
    const context = canvaser.getContext("2d");
    context.font = "30px 'SuttonSignWritingFill'";
    context.fillText(symbolFill(1), 0, 0);
    const imgData = context.getImageData(0, 0, 15, 30).data;
    return !imgData.every(item => item === 0);
  };
  if (!fillReady()) {
    const cssCheck = setInterval(function () {
      if (fillReady()) {
        clearInterval(cssCheck);
        callback();
      }
    }, 100);
  } else {
    callback();
  }
};

export { cssAppend, cssLoaded, cssLoadedFill, cssLoadedLine, symbolFill, symbolLine, symbolSize, symbolText };

/* support ongoing development on https://patreon.com/signwriting */