// space.js, a full (not sparse data storage object) with some utilities.
// This includes from/to fetch, write, files, and ad-hoc strings. [DONE] [DONE] [DONE] [DONE] [DONE]
// It provides combination between Spaces. [DONE]
// It also gives a search utility and a utility to grab an arbitrary section [DONE] [DONE]
const fs = require('fs')
const vec = require('./utils/vec');

function chop(string, n){ // chops a string into n-sized chunks. Assumed to be perfect multiple
  let arr = [];
  for (let sec = 0; sec < string.length; sec++){
    arr.push(string.slice(sec*n,(sec+1)*n));
  }
  return arr;
}

function replace(text, old, repl){ //replaces, in an array `text`, the instances of `old` with `repl`
  for (let i=0; i<text.length; i++){
    if (text[i] == old) text[i] = repl;
  }
  return text;
}

function Space(){
  this.data = [];
  this.loc = []; // Coordinates to represent topleft location of spaces, and aid with .comb
  this.fromfetch = function(tiles, dimension, conform=true){ //tiles is straight from fetch/tileUpdate function, dimension is a min/max pair of y/x coordinates; conform is false for tileUpdate because the cell_props don't actually mean anything; all data is still included
    // destroys tiles, I think. might cause bugs
    this.loc = vec.tileToChar(dimension[0]);
    for (let y=dimension[0][0]; y<=dimension[1][0]; y++){
      for (let line=0; line<8; line++)
        this.data.push([]); // Adds lines
      for (let x=dimension[0][1]; x<=dimension[1][1]; x++){
        if (!tiles[[y,x]]) tiles[[y,x]] = {"content":' '.repeat(16*8),"properties":{"cell_props":{}}};
        tilein.call(this, tiles[[y,x]], y-dimension[0][0]);
      }
    }

    function tilein(tile, tilerow){ //tile is one of the tiles from `tiles`, and tilerow is y-dimension[0]; helper function
      let incl = Object.keys(tile.properties.cell_props).map(linenum => parseInt(linenum)) // list of included lines in the content
      let cont = chop(tile.content,16);
      let read = 0; //line of cont to read
      for (let line=0; line<8; line++){
        let curline = line+8*tilerow;
        if (conform && incl.includes(line)){
          for (let i=0; i<16; i++) this.data[curline].push(' ');
        } else {
          this.data[curline].push(...cont[read]);
          read++;
        }
      }
    }
    return this;
  }

  this.towrite = function(){ // Does no splitting or anything like that. Just returns a list of triplets for the write function
    if (this.loc[0] === undefined) throw "Space.towrite() requires valid loc";
    let writes = [];
    for (let line = 0; line < this.data.length; line++) for (let chr = 0; chr < this.data[line].length; chr++){
      if (this.data[line][chr] == '') continue; // Internal coding for "do not write"
      writes.push([[this.loc[0]+line, this.loc[1]+chr],this.data[line][chr]]);
    }
    return writes;
  }

  this.tofile = function(filename){
    fs.writeFileSync(filename, this.print());
  };
  
  this.print = function(){
    return this.data.map(row => replace(replace(replace(row.slice(),'&','\\&'),'\\','\\\\'),'','&').join('')).join('\n');
  }

  this.fromfile = function(filename){ //Reads an external file into internal data
    this.adhoc(fs.readFileSync(filename,'utf8'));
    return this;
  }

  this.adhoc = function(text){
    text = text.split('\n')
    text = text.map(row => row.split(''));
    this.data = text.map(row => {
      for (let i = 0; i<row.length; i++){
        if (row[i] == '\\') row.splice(i,1);
        else if (row[i] == '&') row[i] = '';
      }
      return row;
    });
    return this;
  }

  this.comb = function(other, func){ // other must have a valid .loc. If this.loc null, treated as offset
    if (! other.loc) throw "The secondary space must have a valid .loc"
    let offset;
    if (this.loc.length == 0) {
      offset = [0, 0];
      this.loc = other.loc;
    } else {
      offset = vec.sub(this.loc, other.loc);
      if (this.data.length > 0)
        this.loc = vec.elem(this.loc, other.loc, (a,b) => Math.min(a,b));
    } // offset is position of other relative to this, so these are mainly definitional.
    // Convert negative offsets of either sort into zero offsets with significant previous whitespace (translation)
    for (let i = 0; i < -offset[0]; i++) this.data.unshift([]);
    if (offset[0] < 0) offset[0] = 0;
    for (let row = 0; row < this.data.length; row++){ // offset[1] < 0 fix
      for (let i = 0; i < -offset[1]; i++) this.data[row].unshift('');
    }
    if (offset[1] < 0) offset[1] = 0;

    // Parse over all relevant tiles and process them into usable chars (this.data is all relevant tiles due to padding)
    while (this.data.length < offset[0]+other.data.length) this.data.push([]); // Row padding
    for (let row = 0; row < this.data.length; row++){
      let otherrow = other.data[row-offset[0]] || [];
      while (this.data[row].length < offset[1]+otherrow.length) this.data[row].push(''); // Character-wise padding
      for (let chr = 0; chr < this.data[row].length; chr++){
        this.data[row][chr] = func(this.data[row][chr], otherrow[chr-offset[1]] || '');
      }
    }
    return this;
  }

  this.search = function(other){ //Returns first instance of `other` subspace (prioritized vertically then horizontally)
    // Non-standard exclusion of this.loc
    let loc = [];
    for (let line=0; line<=this.data.length-other.data.length; line++){ for (let chr=0; chr<=this.data[line].length-other.data[0].length; chr++){
      var match = true;
      for (let y=0; y<other.data.length; y++) for (let x=0; x<other.data[y].length; x++){
        if (this.data[line+y][chr+x] != other.data[y][x]){
          match = false;
          break;
        }
      }
      if (match){
        loc = [line,chr];
        break;
      }
    } if (match) break;}
    return loc;
  }

  this.nullprint = function(){
    let data = [];
    for (let ln of this.data){
      let newln = "";
      for (c of ln){
        if (c === '') newln += '\0';
        else newln += c;
      }
      data.push(newln);
    }
    return data;
  }

  this.regex = function(strlines){
    if (typeof strlines[0] !== 'string') throw ".regex needs arr of strings";
    let lines = [];
    for (let i = 0; i < strlines.length; i++) {
        lines.push(new RegExp(strlines[i], 'g'));
    }
    let data = this.nullprint();
    let loc = [];
    data.forEach( (ln, ind) => {
      if (((data.length - ind) < lines.length)) return;
      let match;
      while ( (match = lines[0].exec(ln)) !== null){
        let xdisp = match.index;
        let lnmatch = true;
        for (let i=1; lines[i] !== undefined; i+= 1){
          let imatch = lines[i].exec(data[ind+i].slice(xdisp));
          if (!imatch || imatch.index !== 0){
            lnmatch = false;
            break;
          }
        }
        if (lnmatch){
          loc.push([ind, xdisp]);
        }
      }
    });
    return loc;
  }

  this.subsection = function(range){ // range is a coordinate pair
    if (range.length !== 2 || range[0].length !== 2) throw "not subsecting a coord pair";
    // Similarly excludes this.loc
    newspace = new Space();
    for (let line=range[0][0]; line<range[1][0]; line++){
      newspace.data.push([]);
      let thisline = this.data[line] || [];
      for (let chr=range[0][1]; chr<range[1][1]; chr++){
        newspace.data[line-range[0][0]].push(thisline[chr] || '');
      }
    }
    newspace.loc = [range[0][0], range[0][1]];
    return newspace;
  }

  this.copy = function(){ // deeply copies `array` and `loc` to a new space
    let newspace = new Space();
    newspace.data = this.data.map(row => row.slice()); // Deep copy
    newspace.loc = this.loc.slice();
    return newspace;
  }
}
    
module.exports = Space