const HELPER_PAGE_URL =
  "http://example.com/browser/dom/tests/browser/page_localstorage_snapshotting_e10s.html";
const HELPER_PAGE_ORIGIN = "http://example.com/";

/* import-globals-from helper_localStorage_e10s.js */

let testDir = gTestPath.substr(0, gTestPath.lastIndexOf("/"));
Services.scriptloader.loadSubScript(testDir + "/helper_localStorage_e10s.js",
                                    this);

function clearOrigin() {
  let principal =
    Services.scriptSecurityManager.createCodebasePrincipalFromOrigin(
      HELPER_PAGE_ORIGIN);
  let request =
    Services.qms.clearStoragesForPrincipal(principal, "default", "ls");
  let promise = new Promise(resolve => {
    request.callback = () => {
      resolve();
    };
  });
  return promise;
}

async function applyMutations(knownTab, mutations) {
  await ContentTask.spawn(
    knownTab.tab.linkedBrowser,
    mutations,
    function(mutations) {
      return content.wrappedJSObject.applyMutations(Cu.cloneInto(mutations,
                                                                 content));
    });
}

async function verifyState(knownTab, expectedState) {
  let actualState = await ContentTask.spawn(
    knownTab.tab.linkedBrowser,
    {},
    function() {
      return content.wrappedJSObject.getState();
    });

  for (let [expectedKey, expectedValue] of Object.entries(expectedState)) {
    ok(actualState.hasOwnProperty(expectedKey), "key present: " + expectedKey);
    is(actualState[expectedKey], expectedValue, "value correct");
  }
  for (let actualKey of Object.keys(actualState)) {
    if (!expectedState.hasOwnProperty(actualKey)) {
      ok(false, "actual state has key it shouldn't have: " + actualKey);
    }
  }
}

async function getKeys(knownTab) {
  let keys = await ContentTask.spawn(
    knownTab.tab.linkedBrowser,
    null,
    function() {
      return content.wrappedJSObject.getKeys();
    });
  return keys;
}

async function beginExplicitSnapshot(knownTab) {
  await ContentTask.spawn(
    knownTab.tab.linkedBrowser,
    null,
    function() {
      return content.wrappedJSObject.beginExplicitSnapshot();
    });
}

async function endExplicitSnapshot(knownTab) {
  await ContentTask.spawn(
    knownTab.tab.linkedBrowser,
    null,
    function() {
      return content.wrappedJSObject.endExplicitSnapshot();
    });
}

// We spin up a ton of child processes.
requestLongerTimeout(4);

/**
 * Verify snapshotting of our localStorage implementation in multi-e10s setup.
 */
add_task(async function() {
  if (!Services.lsm.nextGenLocalStorageEnabled) {
    ok(true, "Test ignored when the next gen local storage is not enabled.");
    return;
  }

  await SpecialPowers.pushPrefEnv({
    set: [
      // Enable LocalStorage's testing API so we can explicitly create
      // snapshots when needed.
      ["dom.storage.testing", true],
    ],
  });

  // Ensure that there is no localstorage data by forcing the origin to be
  // cleared prior to the start of our test..
  await clearOrigin();

  // - Open tabs.  Don't configure any of them yet.
  const knownTabs = new KnownTabs();
  const writerTab1 = await openTestTabInOwnProcess(HELPER_PAGE_URL, "writer1",
    knownTabs);
  const writerTab2 = await openTestTabInOwnProcess(HELPER_PAGE_URL, "writer2",
    knownTabs);
  const readerTab1 = await openTestTabInOwnProcess(HELPER_PAGE_URL, "reader1",
    knownTabs);
  const readerTab2 = await openTestTabInOwnProcess(HELPER_PAGE_URL, "reader2",
    knownTabs);

  const initialMutations = [
    [null, null],
    ["key1", "initial1"],
    ["key2", "initial2"],
    ["key3", "initial3"],
    ["key5", "initial5"],
    ["key6", "initial6"],
    ["key7", "initial7"],
    ["key8", "initial8"],
  ];

  const initialState = {
    key1: "initial1",
    key2: "initial2",
    key3: "initial3",
    key5: "initial5",
    key6: "initial6",
    key7: "initial7",
    key8: "initial8",
  };

  function getPartialPrefill() {
    let size = 0;
    let entries = Object.entries(initialState);
    for (let i = 0; i < entries.length / 2; i++) {
      let entry = entries[i];
      size += entry[0].length + entry[1].length;
    }
    return size;
  }

  const prefillValues = [
    0,                   // no prefill
    getPartialPrefill(), // partial prefill
    -1,                  // full prefill
  ];

  for (let prefillValue of prefillValues) {
    info("Setting prefill value");

    await SpecialPowers.pushPrefEnv({
      set: [
        ["dom.storage.snapshot_prefill", prefillValue],
      ],
    });

    info("Stage 1");

    const setRemoveMutations1 = [
      ["key0", "setRemove10"],
      ["key1", "setRemove11"],
      ["key2", null],
      ["key3", "setRemove13"],
      ["key4", "setRemove14"],
      ["key5", "setRemove15"],
      ["key6", "setRemove16"],
      ["key7", "setRemove17"],
      ["key8", null],
      ["key9", "setRemove19"],
    ];

    const setRemoveState1 = {
      key0: "setRemove10",
      key1: "setRemove11",
      key3: "setRemove13",
      key4: "setRemove14",
      key5: "setRemove15",
      key6: "setRemove16",
      key7: "setRemove17",
      key9: "setRemove19",
    };

    const setRemoveMutations2 = [
      ["key0", "setRemove20"],
      ["key1", null],
      ["key2", "setRemove22"],
      ["key3", "setRemove23"],
      ["key4", "setRemove24"],
      ["key5", "setRemove25"],
      ["key6", "setRemove26"],
      ["key7", null],
      ["key8", "setRemove28"],
      ["key9", "setRemove29"],
    ];

    const setRemoveState2 = {
      key0: "setRemove20",
      key2: "setRemove22",
      key3: "setRemove23",
      key4: "setRemove24",
      key5: "setRemove25",
      key6: "setRemove26",
      key8: "setRemove28",
      key9: "setRemove29",
    };

    // Apply initial mutations using an explicit snapshot. The explicit
    // snapshot here ensures that the parent process have received the changes.
    await beginExplicitSnapshot(writerTab1);
    await applyMutations(writerTab1, initialMutations);
    await endExplicitSnapshot(writerTab1);

    // Begin explicit snapshots in all tabs except readerTab2. All these tabs
    // should see the initial state regardless what other tabs are doing.
    await beginExplicitSnapshot(writerTab1);
    await beginExplicitSnapshot(writerTab2);
    await beginExplicitSnapshot(readerTab1);

    // Apply first array of set/remove mutations in writerTab1 and end the
    // explicit snapshot. This will trigger saving of values in other active
    // snapshots.
    await applyMutations(writerTab1, setRemoveMutations1);
    await endExplicitSnapshot(writerTab1);

    // Begin an explicit snapshot in readerTab2. writerTab1 already ended its
    // explicit snapshot, so readerTab2 should see mutations done by
    // writerTab1.
    await beginExplicitSnapshot(readerTab2);

    // Apply second array of set/remove mutations in writerTab2 and end the
    // explicit snapshot. This will trigger saving of values in other active
    // snapshots, but only if they haven't been saved already.
    await applyMutations(writerTab2, setRemoveMutations2);
    await endExplicitSnapshot(writerTab2);

    // Verify state in readerTab1, it should match the initial state.
    await verifyState(readerTab1, initialState);
    await endExplicitSnapshot(readerTab1);

    // Verify state in readerTab2, it should match the state after the first
    // array of set/remove mutatations have been applied and "commited".
    await verifyState(readerTab2, setRemoveState1);
    await endExplicitSnapshot(readerTab2);

    // Verify final state, it should match the state after the second array of
    // set/remove mutation have been applied and "commited". An explicit
    // snapshot is used.
    await beginExplicitSnapshot(readerTab1);
    await verifyState(readerTab1, setRemoveState2);
    await endExplicitSnapshot(readerTab1);

    info("Stage 2");

    const setRemoveClearMutations1 = [
      ["key0", "setRemoveClear10"],
      ["key1", null],
      [null, null],
    ];

    const setRemoveClearState1 = {
    };

    const setRemoveClearMutations2 = [
      ["key8", null],
      ["key9", "setRemoveClear29"],
      [null, null],
    ];

    const setRemoveClearState2 = {
    };

    // This is very similar to previous stage except that in addition to
    // set/remove, the clear operation is involved too.
    await beginExplicitSnapshot(writerTab1);
    await applyMutations(writerTab1, initialMutations);
    await endExplicitSnapshot(writerTab1);

    await beginExplicitSnapshot(writerTab1);
    await beginExplicitSnapshot(writerTab2);
    await beginExplicitSnapshot(readerTab1);

    await applyMutations(writerTab1, setRemoveClearMutations1);
    await endExplicitSnapshot(writerTab1);

    await beginExplicitSnapshot(readerTab2);

    await applyMutations(writerTab2, setRemoveClearMutations2);
    await endExplicitSnapshot(writerTab2);

    await verifyState(readerTab1, initialState);
    await endExplicitSnapshot(readerTab1);

    await verifyState(readerTab2, setRemoveClearState1);
    await endExplicitSnapshot(readerTab2);

    await beginExplicitSnapshot(readerTab1);
    await verifyState(readerTab1, setRemoveClearState2);
    await endExplicitSnapshot(readerTab1);

    info("Stage 3");

    const changeOrderMutations = [
      ["key1", null],
      ["key2", null],
      ["key3", null],
      ["key5", null],
      ["key6", null],
      ["key7", null],
      ["key8", null],
      ["key8", "initial8"],
      ["key7", "initial7"],
      ["key6", "initial6"],
      ["key5", "initial5"],
      ["key3", "initial3"],
      ["key2", "initial2"],
      ["key1", "initial1"],
    ];

    // Apply initial mutations using an explicit snapshot. The explicit
    // snapshot here ensures that the parent process have received the changes.
    await beginExplicitSnapshot(writerTab1);
    await applyMutations(writerTab1, initialMutations);
    await endExplicitSnapshot(writerTab1);

    // Begin explicit snapshots in all tabs except writerTab2 which is not used
    // in this stage. All these tabs should see the initial order regardless
    // what other tabs are doing.
    await beginExplicitSnapshot(readerTab1);
    await beginExplicitSnapshot(writerTab1);
    await beginExplicitSnapshot(readerTab2);

    // Get all keys in readerTab1 and end the explicit snapshot. No mutations
    // have been applied yet.
    let tab1Keys = await getKeys(readerTab1);
    await endExplicitSnapshot(readerTab1);

    // Apply mutations that change the order of keys and end the explicit
    // snapshot. The state is unchanged. This will trigger saving of key order
    // in other active snapshots, but only if the order hasn't been saved
    // already.
    await applyMutations(writerTab1, changeOrderMutations);
    await endExplicitSnapshot(writerTab1);

    // Get all keys in readerTab2 and end the explicit snapshot. Change order
    // mutations have been applied, but the order should stay unchanged.
    let tab2Keys = await getKeys(readerTab2);
    await endExplicitSnapshot(readerTab2);

    // Verify the key order is the same.
    is(tab2Keys.length, tab1Keys.length, "Correct keys length");
    for (let i = 0; i < tab2Keys.length; i++) {
      is(tab2Keys[i], tab1Keys[i], "Correct key");
    }

    // Verify final state, it should match the initial state since applied
    // mutations only changed the key order. An explicit snapshot is used.
    await beginExplicitSnapshot(readerTab1);
    await verifyState(readerTab1, initialState);
    await endExplicitSnapshot(readerTab1);
  }

  // - Clean up.
  await cleanupTabs(knownTabs);

  clearOrigin();
});