// Copyright 2020-2023 Nym Technologies SA
//
// 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.

const RUST_WASM_URL = "mix_fetch_wasm_bg.wasm"
const GO_WASM_URL = "go_conn.wasm"

importScripts('mix_fetch_wasm.js');
importScripts('wasm_exec.js');

console.log('Initializing worker');

// wasm_bindgen creates a global variable (with the exports attached) that is in scope after `importScripts`
const {
    default_debug,
    no_cover_debug,
    NymClient,
    set_panic_hook,
    Config,
    GatewayEndpointConfig,
    ClientStorage,
    MixFetchConfig,
    send_client_data,
    start_new_mixnet_connection,
    setupMixFetch,
    disconnectMixFetch,
    setupMixFetchWithConfig,
    mix_fetch_initialised,
    finish_mixnet_connection
} = wasm_bindgen;

let client = null;
let tester = null;
const go = new Go(); // Defined in wasm_exec.js
var goWasm;
let mixFetchReady = false;

function sendLog(message, level = 'info') {
    self.postMessage({
        kind: 'Log',
        args: { message, level },
    });
}

function sendReady() {
    self.postMessage({ kind: 'MixFetchReady' });
}

function sendError(error) {
    self.postMessage({
        kind: 'MixFetchError',
        args: { error: String(error) },
    });
}

async function logFetchResult(res) {
    console.log(res)
    let text = await res.text()
    console.log("HEADERS:     ", ...res.headers)
    console.log("STATUS:      ", res.status)
    console.log("STATUS TEXT: ", res.statusText)
    console.log("OK:          ", res.ok)
    console.log("TYPE:        ", res.type)
    console.log("URL:         ", res.url)
    console.log("BODYUSED:    ", res.bodyUsed)
    console.log("REDIRECTED:  ", res.redirected)
    console.log("TEXT:        ", text)

    self.postMessage({
        kind: 'DisplayString',
        args: {
            rawString: text,
        },
    });
}

async function wasm_bindgenSetup() {
    const preferredGateway = "6qQYb4ArXANU6HJDxzH4PFCUqYb39Dae2Gem2KpxescM";
    const validator = 'https://qa-nym-api.qa.nymte.ch/api';

    // local
    const mixFetchNetworkRequesterAddress = "2o47bhnXWna6VEyt4mXMGQQAbXfpKmX7BkjkxUz8uQVi.6uQGnCqSczpXwh86NdbsCoDDXuqZQM9Uwko8GE7uC9g8@6qQYb4ArXANU6HJDxzH4PFCUqYb39Dae2Gem2KpxescM";
    // const mixFetchNetworkRequesterAddress= "GqiGWmKRCbGQFSqH88BzLKijvZgipnqhmbNFsmkZw84t.4L8sXFuAUyUYyHZYgMdM3AtiusKnYUft6Pd8e41rrCHA@6qQYb4ArXANU6HJDxzH4PFCUqYb39Dae2Gem2KpxescM";

    // STEP 1. construct config
    // those are just some examples, there are obviously more permutations;
    // note, the extra optional argument is of the following type:
    // /*
    //     export interface MixFetchConfigOpts {
    //         id?: string;
    //         nymApi?: string;
    //         nyxd?: string;
    //         debug?: DebugWasm;
    //     }
    //  */
    //
    // const debug = no_cover_debug()
    //
    // #1
    // const config = new MixFetchConfig(mixFetchNetworkRequesterAddress, { id: 'my-awesome-mix-fetch-client', nymApi: validator, debug: debug} );
    // #2
    // const config = new MixFetchConfig(mixFetchNetworkRequesterAddress, { nymApi: validator, debug: debug} );
    // #3
    // const config = new MixFetchConfig(mixFetchNetworkRequesterAddress, { id: 'my-awesome-mix-fetch-client' } );
    //
    // #4
    const differentDebug = default_debug()
    const updatedTraffic = differentDebug.traffic;
    updatedTraffic.use_extended_packet_size = true
    updatedTraffic.average_packet_delay_ms = 666;
    differentDebug.traffic = updatedTraffic;

    const config = new MixFetchConfig(mixFetchNetworkRequesterAddress, {debug: differentDebug});
    //
    // // STEP 2. setup the client
    // // note, the extra optional argument is of the following type:
    // /*
    //     export interface MixFetchOptsSimple {
    //         preferredGateway?: string;
    //         storagePassphrase?: string;
    //     }
    //  */
    // #1
    await setupMixFetchWithConfig(config)
    //
    // #2
    // await setupMixFetchWithConfig(config, { storagePassphrase: "foomp" })
    //
    // #3
    // await setupMixFetchWithConfig(config, { storagePassphrase: "foomp", preferredGateway })
}

async function nativeSetup(preferredGateway) {
    sendLog('Setting up MixFetch...');
    if (preferredGateway) {
        sendLog(`Using preferred gateway: ${preferredGateway}`);
    } else {
        sendLog('Using random gateway selection');
    }

    const noCoverTrafficOverride = {
        traffic: {disableMainPoissonPacketDistribution: true},
        coverTraffic: {disableLoopCoverTrafficStream: true},
    }
    const mixFetchOverride = {
        requestTimeoutMs: 60000
    }

    const opts = {
        forceTls: true,
        clientId: "my-client",
        clientOverride: noCoverTrafficOverride,
        mixFetchOverride,
    };

    if (preferredGateway) {
        opts.preferredGateway = preferredGateway;
    }

    sendLog('Calling setupMixFetch...');
    await setupMixFetch(opts);
    sendLog('setupMixFetch completed');
}

async function startMixFetch(preferredGateway) {
    sendLog('Instantiating MixFetch...');

    try {
        await nativeSetup(preferredGateway);
        mixFetchReady = true;
        sendLog('MixFetch client running!');
        sendReady();
    } catch (e) {
        sendLog('Failed to start MixFetch: ' + e, 'error');
        sendError(e);
    }
}

async function handleFetchPayload(target) {
    if (!mixFetchReady) {
        sendLog('MixFetch not ready yet', 'error');
        return;
    }

    const url = target;
    const args = {mode: "unsafe-ignore-cors"};

    try {
        sendLog(`Fetching: ${url}`);
        const mixFetchRes = await mixFetch(url, args);
        sendLog('Fetch completed');
        await logFetchResult(mixFetchRes);
    } catch (e) {
        sendLog('Fetch request failure: ' + e, 'error');
        console.error("mix fetch request failure: ", e);
    }
}

async function handlePostPayload(url, body) {
    if (!mixFetchReady) {
        sendLog('MixFetch not ready yet', 'error');
        return;
    }

    const args = {
        method: 'POST',
        mode: "unsafe-ignore-cors",
        headers: {
            'Content-Type': 'application/json',
        },
        body: body,
    };

    try {
        sendLog(`POST request to: ${url}`);
        sendLog(`POST body: ${body}`);
        const mixFetchRes = await mixFetch(url, args);
        sendLog('POST completed');
        await logFetchResult(mixFetchRes);
    } catch (e) {
        sendLog('POST request failure: ' + e, 'error');
        console.error("mix fetch POST request failure: ", e);
    }
}

function setupMessageHandler() {
    self.onmessage = async event => {
        if (event.data && event.data.kind) {
            switch (event.data.kind) {
                case 'StartMixFetch': {
                    const { preferredGateway } = event.data.args;
                    await startMixFetch(preferredGateway);
                    break;
                }
                case 'FetchPayload': {
                    const { target } = event.data.args;
                    await handleFetchPayload(target);
                    break;
                }
                case 'PostPayload': {
                    const { url, body } = event.data.args;
                    await handlePostPayload(url, body);
                    break;
                }
            }
        }
    };
}


// TODO: look into https://www.aaron-powell.com/posts/2019-02-08-golang-wasm-5-compiling-with-webpack/
async function loadGoWasm() {
    const resp = await fetch(GO_WASM_URL);

    if ('instantiateStreaming' in WebAssembly) {
        const wasmObj = await WebAssembly.instantiateStreaming(resp, go.importObject)
        goWasm = wasmObj.instance
        go.run(goWasm)
    } else {
        const bytes = await resp.arrayBuffer()
        const wasmObj = await WebAssembly.instantiate(bytes, go.importObject)
        goWasm = wasmObj.instance
        go.run(goWasm)
    }
}

function setupRsGoBridge() {
    // (note: reason for intermediate `__rs_go_bridge__` object is to decrease global scope bloat
    // and to discourage users from trying to call those methods directly)
    self.__rs_go_bridge__ = {}
    self.__rs_go_bridge__.send_client_data = send_client_data
    self.__rs_go_bridge__.start_new_mixnet_connection = start_new_mixnet_connection
    self.__rs_go_bridge__.mix_fetch_initialised = mix_fetch_initialised
    self.__rs_go_bridge__.finish_mixnet_connection = finish_mixnet_connection
}

async function main() {
    sendLog('Worker starting...');

    // load rust WASM package
    sendLog('Loading Rust WASM...');
    await wasm_bindgen(RUST_WASM_URL);
    sendLog('Loaded Rust WASM');

    // load go WASM package
    sendLog('Loading Go WASM...');
    await loadGoWasm();
    sendLog('Loaded Go WASM');

    // sets up better stack traces in case of in-rust panics
    set_panic_hook();

    setupRsGoBridge();

    goWasmSetLogging("trace")

    // Set up message handler (MixFetch will be started on demand)
    setupMessageHandler();

    sendLog('Worker ready - click Start MixFetch to begin');
}

// Let's get started!
main();