if (typeof btoa==="undefined") {
  // Don't define btoa as a function here because Apple's
  // iOS browser defines the function even though it's in
  // an IF statement that is never executed!
  btoa = function(d) { return Buffer.from(d).toString('base64'); }
}

// Converts a string into most efficient way to send to Espruino (either json, base64, or compressed base64)
function toJS(txt) {
  let isBinary = false;
  for (let i=0;i<txt.length;i++) {
    let ch = txt.charCodeAt(i);
    if (ch==0 || ch>127) isBinary=true;
  }
  let json = JSON.stringify(txt);
  let b64 = "atob("+JSON.stringify(btoa(txt))+")";
  let js = (isBinary || (b64.length < json.length)) ? b64 : json;

  if (typeof heatshrink !== "undefined") {
    let ua = new Uint8Array(txt.length);
    for (let i=0;i<txt.length;i++)  ua[i] = txt.charCodeAt(i);
    let c = heatshrink.compress(ua);
    let cs = "";
    for (let i=0;i<c.length;i++)
      cs += String.fromCharCode(c[i]);
    cs = 'require("heatshrink").decompress(atob("'+btoa(cs)+'"))';
    // if it's more than a little smaller, use compressed version
    if (cs.length*4 < js.length*3)
      js = cs;
  }

  return js;
}

if ("undefined"!=typeof module)
  Espruino = require("./espruinotools.js");

const AppInfo = {
  /* Get files needed for app.
     options = {
        fileGetter : callback for getting URL,
        settings : global settings object
      }
      */
  getFiles : (app,options) => {
    return new Promise((resolve,reject) => {
      // Load all files
      Promise.all(app.storage.map(storageFile => {
        if (storageFile.content!==undefined)
          return Promise.resolve(storageFile);
        else if (storageFile.url)
          return options.fileGetter(`apps/${app.id}/${storageFile.url}`).then(content => {
            if (storageFile.url.endsWith(".js") && !storageFile.url.endsWith(".min.js")) { // if original file ends in '.js'...
              return Espruino.transform(content, {
                SET_TIME_ON_WRITE : false,
                PRETOKENISE : options.settings.pretokenise,
                //MINIFICATION_LEVEL : "ESPRIMA", // disable due to https://github.com/espruino/BangleApps/pull/355#issuecomment-620124162
                builtinModules : "Flash,Storage,heatshrink,tensorflow,locale"
              });
            } else
              return content;
          }).then(content => {
            return {
              name : storageFile.name,
              content : content,
              evaluate : storageFile.evaluate
            }});
        else return Promise.resolve();
      })).then(fileContents => { // now we just have a list of files + contents...
        // filter out empty files
        fileContents = fileContents.filter(x=>x!==undefined);
        // What about minification?
        // Add app's info JSON
        return AppInfo.createAppJSON(app, fileContents);
      }).then(fileContents => {
        // then map each file to a command to load into storage
        fileContents.forEach(storageFile => {
          // format ready for Espruino
          if (storageFile.evaluate) {
            let js = storageFile.content.trim();
            if (js.endsWith(";"))
              js = js.slice(0,-1);
            storageFile.cmd = `\x10require('Storage').write(${JSON.stringify(storageFile.name)},${js});`;
          } else {
            let code = storageFile.content;
            // write code in chunks, in case it is too big to fit in RAM (fix #157)
            let CHUNKSIZE = 4096;
            storageFile.cmd = `\x10require('Storage').write(${JSON.stringify(storageFile.name)},${toJS(code.substr(0,CHUNKSIZE))},0,${code.length});`;
            for (let i=CHUNKSIZE;i<code.length;i+=CHUNKSIZE)
              storageFile.cmd += `\n\x10require('Storage').write(${JSON.stringify(storageFile.name)},${toJS(code.substr(i,CHUNKSIZE))},${i});`;
          }
        });
        resolve(fileContents);
      }).catch(err => reject(err));
    });
  },
  createAppJSON : (app, fileContents) => {
    return new Promise((resolve,reject) => {
      let appJSONName = app.id+".info";
      // Check we don't already have a JSON file!
      let appJSONFile = fileContents.find(f=>f.name==appJSONName);
      if (appJSONFile) reject("App JSON file explicitly specified!");
      // Now actually create the app JSON
      let json = {
        id : app.id
      };
      if (app.shortName) json.name = app.shortName;
      else json.name = app.name;
      if (app.type && app.type!="app") json.type = app.type;
      if (fileContents.find(f=>f.name==app.id+".app.js"))
        json.src = app.id+".app.js";
      if (fileContents.find(f=>f.name==app.id+".img"))
        json.icon = app.id+".img";
      if (app.sortorder) json.sortorder = app.sortorder;
      if (app.version) json.version = app.version;
      let fileList = fileContents.map(storageFile=>storageFile.name);
      fileList.unshift(appJSONName); // do we want this? makes life easier!
      json.files = fileList.join(",");
      if ('data' in app) {
        let data = {dataFiles: [], storageFiles: []};
        // add "data" files to appropriate list
        app.data.forEach(d=>{
          if (d.storageFile) data.storageFiles.push(d.name||d.wildcard)
          else data.dataFiles.push(d.name||d.wildcard)
        })
        const dataString = AppInfo.makeDataString(data)
        if (dataString) json.data = dataString
      }
      fileContents.push({
        name : appJSONName,
        content : JSON.stringify(json)
      });
      resolve(fileContents);
    });
  },
  // (<appid>.info).data holds filenames of data: both regular and storageFiles
  // These are stored as:  (note comma vs semicolons)
  //   "fil1,file2", "file1,file2;storageFileA,storageFileB" or ";storageFileA"
  /**
   * Convert appid.info "data" to object with file names/patterns
   * Passing in undefined works
   * @param data "data" as stored in appid.info
   * @returns {{storageFiles:[], dataFiles:[]}}
   */
  parseDataString(data) {
    data = data || '';
    let [files = [], storage = []] = data.split(';').map(d => d.split(','))
    return {dataFiles: files, storageFiles: storage}
  },
  /**
   * Convert object with file names/patterns to appid.info "data" string
   * Passing in an incomplete object will not work
   * @param data {{storageFiles:[], dataFiles:[]}}
   * @returns {string} "data" to store in appid.info
   */
  makeDataString(data) {
    if (!data.dataFiles.length && !data.storageFiles.length) { return '' }
    if (!data.storageFiles.length) { return data.dataFiles.join(',') }
    return [data.dataFiles.join(','),data.storageFiles.join(',')].join(';')
  },
};

if ("undefined"!=typeof module)
  module.exports = AppInfo;