wallet-core/extension/background/wallet.ts

/// <reference path="../decl/urijs/URIjs.d.ts" />
/// <reference path="../decl/chrome/chrome.d.ts" />
'use strict';

const DB_NAME = "taler";
const DB_VERSION = 1;


/**
 * Return a promise that resolves
 * to the taler wallet db.
 */
function openTalerDb() {
  return new Promise((resolve, reject) => {
    let req = indexedDB.open(DB_NAME, DB_VERSION);
    req.onerror = (e) => {
      reject(e);
    };
    req.onsuccess = (e : any) => {
      resolve(e.target.result);
    };
    req.onupgradeneeded = (event : any) => {
      let db = event.target.result;
      console.log ("DB: upgrade needed: oldVersion = " + event.oldVersion);
      db = event.target.result;
      switch (event.oldVersion) {
        case 0: // DB does not exist yet
          db.createObjectStore("mints", { keyPath: "baseUrl" });
          db.createObjectStore("reserves", { keyPath: "reserve_pub"});
          db.createObjectStore("denoms", { keyPath: "denom_pub" });
          db.createObjectStore("coins", { keyPath: "coin_pub" });
          db.createObjectStore("withdrawals", { keyPath: "id", autoIncrement: true });
          db.createObjectStore("transactions", { keyPath: "id", autoIncrement: true });
          break;
      }
    };
  });
}


function canonicalizeBaseUrl(url) {
  let x = new URI(url);
  if (!x.protocol()) {
    x.protocol("https");
  }
  x.path(x.path() + "/").normalizePath();
  x.fragment();
  x.query();
  return x.href()
}


function confirmReserve(db, detail, sendResponse) {
  console.log('detail: ' + JSON.stringify(detail));
  let reservePriv = EddsaPrivateKey.create();
  let reservePub = reservePriv.getPublicKey();
  let form = new FormData();
  let now = (new Date()).toString();
  form.append(detail.field_amount, detail.amount_str);
  form.append(detail.field_reserve_pub, reservePub.toCrock());
  form.append(detail.field_mint, detail.mint);
  // XXX: set bank-specified fields.
  let myRequest = new XMLHttpRequest();
  console.log("making request to " + detail.post_url);
  myRequest.open('post', detail.post_url);
  myRequest.send(form);
  let mintBaseUrl = canonicalizeBaseUrl(detail.mint);
  myRequest.addEventListener('readystatechange', (e) => {
    if (myRequest.readyState == XMLHttpRequest.DONE) {
      // TODO: extract as interface
      let resp = {
        status: myRequest.status,
        text: myRequest.responseText,
        success: undefined,
        backlink: undefined
      };
      let reserveRecord = {
        reserve_pub: reservePub.toCrock(),
        reserve_priv: reservePriv.toCrock(),
        mint_base_url: mintBaseUrl,
        created: now,
        last_query: null,
        current_amount: null,
        // XXX: set to actual amount
        initial_amount: null
      };
      // XXX: insert into db.
      switch (myRequest.status) {
        case 200:
          resp.success = true;
          // We can't show the page directly, so
          // we show some generic page from the wallet.
          resp.backlink = chrome.extension.getURL("pages/reserve-success.html");
          let tx = db.transaction(['reserves'], 'readwrite');
          tx.objectStore('reserves').add(reserveRecord);
          tx.addEventListener('complete', (e) => {
            console.log('tx complete, pk was ' + reserveRecord.reserve_pub);
            sendResponse(resp);
            var mint;
            updateMintFromUrl(db, reserveRecord.mint_base_url)
                .then((m) => { mint = m; return updateReserve(db, reservePub, mint); })
                .then((reserve) => depleteReserve(db, reserve, mint));
          });
          break;
        default:
          resp.success = false;
          sendResponse(resp);
      }
    }
  });
  // Allow async response
  return true;
}


function copy(o) {
  return JSON.parse(JSON.stringify(o));
}


function rankDenom(denom1: any, denom2: any) {
  // Slow ... we should find a better way than to convert it evert time.
  let v1 = new Amount(denom1.value);
  let v2 = new Amount(denom2.value);
  return (-1) * v1.cmp(v2);
}


function withdraw(denom, reserve, mint): Promise<void> {
  console.log("in withdraw");
  let wd: any = {};
  wd.denom_pub = denom.denom_pub;
  wd.reserve_pub = reserve.reserve_pub;
  let a = new Arena();
  try {
    let reservePriv = new EddsaPrivateKey();
    reservePriv.loadCrock(reserve.reserve_priv);
    let reservePub = new EddsaPublicKey();
    reservePub.loadCrock(reserve.reserve_pub);
    let denomPub = RsaPublicKey.fromCrock(denom.denom_pub);
    let coinPriv = EddsaPrivateKey.create();
    let coinPub = coinPriv.getPublicKey();
    let blindingFactor = RsaBlindingKey.create(1024);
    let pubHash: HashCode = coinPub.hash();
    console.log("about to blind");
    let ev: ByteArray = rsaBlind(pubHash, blindingFactor, denomPub);
    console.log("blinded");

    if (!denom.fee_withdraw) {
      throw Error("Field fee_withdraw missing");
    }

    let amountWithFee = new Amount(denom.value);
    amountWithFee.add(new Amount(denom.fee_withdraw));
    let withdrawFee = new Amount(denom.fee_withdraw);

    // Signature
    let withdrawRequest = new WithdrawRequestPS();
    withdrawRequest.set("reserve_pub", reservePub);
    withdrawRequest.set("amount_with_fee", amountWithFee.toNbo());
    withdrawRequest.set("withdraw_fee", withdrawFee.toNbo());
    withdrawRequest.set("h_denomination_pub", denomPub.encode().hash());
    withdrawRequest.set("h_coin_envelope", ev.hash());
    console.log("about to sign");
    var sig = eddsaSign(withdrawRequest.toPurpose(), reservePriv);
    console.log("signed");
    wd.reserve_sig = sig.toCrock();
    wd.coin_ev = ev.toCrock();
  } finally {
    a.destroy();
  }

  console.log("crypto done, doing request");

  console.log("request:");
  console.log(JSON.stringify(wd));

  return new Promise<void>((resolve, reject) => {
    let reqUrl = URI("reserve/withdraw").absoluteTo(mint.baseUrl);
    let myRequest = new XMLHttpRequest();
    console.log("making request to " + reqUrl.href());
    myRequest.open('post', reqUrl.href());
    myRequest.setRequestHeader("Content-Type", "application/json;charset=UTF-8");
    myRequest.send(JSON.stringify(wd));
    myRequest.addEventListener('readystatechange', (e) => {
      if (myRequest.readyState == XMLHttpRequest.DONE) {
        if (myRequest.status != 200) {
          console.log("Withdrawal failed, status ", myRequest.status);
          reject();
          return;
        }
        console.log("Withdrawal successful");
        console.log(myRequest.responseText);
        resolve();
      } else {
        console.log("ready state change to", myRequest.status);
      }
    });
  });

}


/**
 * Withdraw coins from a reserve until it is empty.
 */
function depleteReserve(db, reserve, mint) {
  let denoms = copy(mint.keys.denoms);
  let remaining = new Amount(reserve.current_amount);
  denoms.sort(rankDenom);
  let workList = []
  for (let i = 0; i < 1000; i++) {
    let found = false;
    for (let d of denoms) {
      let cost = new Amount(d.value);
      cost.add(new Amount(d.fee_withdraw));
      if (remaining.cmp(cost) < 0) {
        continue;
      }
      found = true;
      remaining.sub(cost);
      workList.push([d, reserve, mint]);
    }
    if (!found) {
      break;
    }
  }

  // Do the request one by one.
  function work(): void {
    if (workList.length == 0) {
      return;
    }
    console.log("doing work");
    let w = workList.pop();
    withdraw(w[0], w[1], w[2])
        .then(() => work());
  }

  work();
}


function updateReserve(db, reservePub: EddsaPublicKey, mint) {
  let reserve;
  return new Promise((resolve, reject) => {
    let tx = db.transaction(['reserves']);
    tx.objectStore('reserves').get(reservePub.toCrock()).onsuccess = (e) => {
      let reserve = e.target.result;
      let reqUrl = URI("reserve/status").absoluteTo(mint.baseUrl);
      reqUrl.query({'reserve_pub': reservePub.toCrock()});
      let myRequest = new XMLHttpRequest();
      console.log("making request to " + reqUrl.href());
      myRequest.open('get', reqUrl.href());
      myRequest.send();
      myRequest.addEventListener('readystatechange', (e) => {
        if (myRequest.readyState == XMLHttpRequest.DONE) {
          if (myRequest.status != 200) {
            reject();
            return;
          }
          let reserveInfo = JSON.parse(myRequest.responseText);
          console.log("got response " + JSON.stringify(reserveInfo));
          reserve.current_amount = reserveInfo.balance;
          let tx = db.transaction(['reserves'], 'readwrite');
          console.log("putting updated reserve " + JSON.stringify(reserve));
          tx.objectStore('reserves').put(reserve);
          tx.oncomplete = (e) => {
            resolve(reserve);
          };
        }
      });
    };
  });

}


/**
 * Update or add mint DB entry by fetching the /keys information.
 * Optionally link the reserve entry to the new or existing
 * mint entry in then DB.
 */
function updateMintFromUrl(db, baseUrl) {
  console.log("base url is " + baseUrl);
  let reqUrl = URI("keys").absoluteTo(baseUrl);
  let myRequest = new XMLHttpRequest();
  myRequest.open('get', reqUrl.href());
  myRequest.send();
  return new Promise((resolve, reject) => {
    myRequest.addEventListener('readystatechange', (e) => {
      console.log("state change to " + myRequest.readyState);
      if (myRequest.readyState == XMLHttpRequest.DONE) {
        if (myRequest.status == 200) {
          console.log("got /keys");
          let mintKeysJson = JSON.parse(myRequest.responseText);
          if (!mintKeysJson) {
            console.log("keys invalid");
            reject();
          } else {
            let mint = {
              baseUrl: baseUrl,
              keys: mintKeysJson
            };
            let tx = db.transaction(['mints'], 'readwrite');
            tx.objectStore('mints').put(mint);
            tx.oncomplete = (e) => {
              resolve(mint);
            };
          }
        } else {
          console.log("/keys request failed with status " + myRequest.status);
          // XXX: also write last error to DB to show in the UI
          reject();
        }
      }
    });
  });
}


function dumpDb(db, detail, sendResponse) {
  let dump = {
    name: db.name,
    version: db.version,
    stores: {}
  };
  console.log("stores: " + JSON.stringify(db.objectStoreNames));
  let tx = db.transaction(db.objectStoreNames);
  tx.addEventListener('complete', (e) => {
      sendResponse(dump);
  });
  for (let i = 0; i < db.objectStoreNames.length; i++) {
    let name = db.objectStoreNames[i];
    let storeDump = {};
    dump.stores[name] = storeDump;
    let store = tx.objectStore(name).openCursor().addEventListener('success', (e) => {
      let cursor = e.target.result;
      if (cursor) {
        storeDump[cursor.key] = cursor.value;
        cursor.continue();
      }
    });
  }
  return true;
}


openTalerDb().then((db) => {
  console.log("db loaded");
  chrome.runtime.onMessage.addListener(
    function (req, sender, onresponse) {
      let dispatch = {
        "confirm-reserve": confirmReserve,
        "dump-db": dumpDb
      }
      return dispatch[req.type](db, req.detail, onresponse);
    });
});