/*
Copyright 2020 The Matrix.org Foundation C.I.C.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

import {createFetchRequest} from "./dom/request/fetch.js";
import {xhrRequest} from "./dom/request/xhr.js";
import {StorageFactory} from "../../matrix/storage/idb/StorageFactory.js";
import {SessionInfoStorage} from "../../matrix/sessioninfo/localstorage/SessionInfoStorage.js";
import {OlmWorker} from "../../matrix/e2ee/OlmWorker.js";
import {RootView} from "./ui/RootView.js";
import {Clock} from "./dom/Clock.js";
import {ServiceWorkerHandler} from "./dom/ServiceWorkerHandler.js";
import {History} from "./dom/History.js";
import {OnlineStatus} from "./dom/OnlineStatus.js";
import {Crypto} from "./dom/Crypto.js";
import {estimateStorageUsage} from "./dom/StorageEstimate.js";
import {WorkerPool} from "./dom/WorkerPool.js";
import {BlobHandle} from "./dom/BlobHandle.js";
import {downloadInIframe} from "./dom/download.js";

function addScript(src) {
    return new Promise(function (resolve, reject) {
        var s = document.createElement("script");
        s.setAttribute("src", src );
        s.onload=resolve;
        s.onerror=reject;
        document.body.appendChild(s);
    });
}

async function loadOlm(olmPaths) {
    // make crypto.getRandomValues available without
    // a prefix on IE11, needed by olm to work
    if (window.msCrypto && !window.crypto) {
        window.crypto = window.msCrypto;
    }
    if (olmPaths) {
        if (window.WebAssembly) {
            await addScript(olmPaths.wasmBundle);
            await window.Olm.init({locateFile: () => olmPaths.wasm});
        } else {
            await addScript(olmPaths.legacyBundle);
            await window.Olm.init();
        }
        return window.Olm;
    }
    return null;
}

// make path relative to basePath,
// assuming it and basePath are relative to document
function relPath(path, basePath) {
    const idx = basePath.lastIndexOf("/");
    const dir = idx === -1 ? "" : basePath.slice(0, idx);
    const dirCount = dir.length ? dir.split("/").length : 0;
    return "../".repeat(dirCount) + path;
}

async function loadOlmWorker(paths) {
    const workerPool = new WorkerPool(paths.worker, 4);
    await workerPool.init();
    const path = relPath(paths.olm.legacyBundle, paths.worker);
    await workerPool.sendAll({type: "load_olm", path});
    const olmWorker = new OlmWorker(workerPool);
    return olmWorker;
}


export class Platform {
    constructor(container, paths, cryptoExtras = null) {
        this._paths = paths;
        this._container = container;
        this.clock = new Clock();
        this.history = new History();
        this.onlineStatus = new OnlineStatus();
        this._serviceWorkerHandler = null;
        if (paths.serviceWorker && "serviceWorker" in navigator) {
            this._serviceWorkerHandler = new ServiceWorkerHandler();
            this._serviceWorkerHandler.registerAndStart(paths.serviceWorker);
        }
        this.crypto = new Crypto(cryptoExtras);
        this.storageFactory = new StorageFactory(this._serviceWorkerHandler);
        this.sessionInfoStorage = new SessionInfoStorage("hydrogen_sessions_v1");
        this.estimateStorageUsage = estimateStorageUsage;
        this.random = Math.random;
        if (typeof fetch === "function") {
            this.request = createFetchRequest(this.clock.createTimeout);
        } else {
            this.request = xhrRequest;
        }
        const isIE11 = !!window.MSInputMethodContext && !!document.documentMode;
        this.isIE11 = isIE11;
    }

    get updateService() {
        return this._serviceWorkerHandler;
    }

    loadOlm() {
        return loadOlm(this._paths.olm);
    }

    async loadOlmWorker() {
        if (!window.WebAssembly) {
            return await loadOlmWorker(this._paths);
        }
    }

    createAndMountRootView(vm) {
        if (this.isIE11) {
            this._container.className += " legacy";
        }
        window.__hydrogenViewModel = vm;
        const view = new RootView(vm);
        this._container.appendChild(view.mount());
    }

    setNavigation(navigation) {
        this._serviceWorkerHandler?.setNavigation(navigation);
    }

    createBlob(buffer, mimetype) {
        return BlobHandle.fromBuffer(buffer, mimetype);
    }

    saveFileAs(blobHandle, filename) {
        if (navigator.msSaveBlob) {
            navigator.msSaveBlob(blobHandle.blob, filename);
        } else {
            downloadInIframe(this._container, this._paths.downloadSandbox, blobHandle.blob, filename);
        }
    }

    openFile(mimeType = null) {
        const input = document.createElement("input");
        input.setAttribute("type", "file");
        if (mimeType) {
            input.setAttribute("accept", mimeType);
        }
        const promise = new Promise((resolve, reject) => {
            const checkFile = () => {
                input.removeEventListener("change", checkFile, true);
                const file = input.files[0];
                if (file) {
                    resolve({name: file.name, blob: BlobHandle.fromFile(file)});
                } else {
                    reject(new Error("No file selected"));
                }
            }
            input.addEventListener("change", checkFile, true);
        });
        input.click();
        return promise;
    }
}