// A minimal WebDriver client for geckodriver, plus the privileged console
// reader the error assertions are built on. No npm dependencies: global
// fetch and child_process against geckodriver's HTTP API is less code than
// a driver library and keeps the harness at zero packages.
//
// Run through script/test-e2e-firefox, which builds dist/firefox/ and the
// pinned container around this. FIREFOX_BIN and GECKODRIVER locate the two
// binaries; the image sets both.

"use strict";

const { spawn } = require("child_process");
const net = require("net");

const FIREFOX_BIN = process.env.FIREFOX_BIN || "firefox";
const GECKODRIVER = process.env.GECKODRIVER || "geckodriver";

// The extension id declared in manifest/firefox.json, and the uuid the
// popup is served from. Firefox normally assigns that uuid randomly per
// profile, which would make the popup URL undiscoverable without querying
// privileged state; setting extensions.webextensions.uuids before launch
// pins it instead. This only works because the manifest declares a fixed
// browser_specific_settings.gecko.id — without one the mapping has no key.
const EXTENSION_ID = "autistmask@sneak.berlin";
const EXTENSION_UUID = "aaaaaaaa-bbbb-cccc-dddd-eeeeeeeeeeee";
const EXTENSION_ORIGIN = "moz-extension://" + EXTENSION_UUID;

// The W3C web element identifier. Getting the last character wrong yields
// an element reference of "undefined" and a bewildering "element with the
// reference undefined is not known" from geckodriver, so findElement()
// below checks for the key rather than indexing blindly.
const WEB_ELEMENT_KEY = "element-6066-11e4-a52e-4f735466cecf";

const SCRIPT_TIMEOUT_MS = 120000;
const DEFAULT_WAIT_MS = 20000;
const POLL_INTERVAL_MS = 100;

function sleep(ms) {
    return new Promise((resolve) => setTimeout(resolve, ms));
}

// An ephemeral port picked by the kernel, then handed to geckodriver.
// There is a race between closing this listener and geckodriver binding,
// but this host runs many sessions at once and a fixed 4444 is a
// guaranteed collision rather than a possible one.
function freePort() {
    return new Promise((resolve, reject) => {
        const srv = net.createServer();
        srv.on("error", reject);
        srv.listen(0, "127.0.0.1", () => {
            const { port } = srv.address();
            srv.close(() => resolve(port));
        });
    });
}

class WebDriverError extends Error {
    constructor(command, body) {
        const v = (body && body.value) || {};
        super(
            command +
                " failed: " +
                (v.error || "unknown error") +
                ": " +
                (v.message || JSON.stringify(body)),
        );
        this.name = "WebDriverError";
        this.error = v.error;
    }
}

class Driver {
    constructor(proc, base) {
        this.proc = proc;
        this.base = base;
        this.sessionId = null;
        this.context = "content";
    }

    async send(method, path, body) {
        const url = this.base + path;
        const res = await fetch(url, {
            method,
            headers: { "Content-Type": "application/json" },
            body: body === undefined ? undefined : JSON.stringify(body),
        });
        const text = await res.text();
        let parsed;
        try {
            parsed = JSON.parse(text);
        } catch {
            throw new Error(
                method + " " + path + ": non-JSON response: " + text,
            );
        }
        if (!res.ok) throw new WebDriverError(method + " " + path, parsed);
        return parsed.value;
    }

    session(method, path, body) {
        return this.send(method, "/session/" + this.sessionId + path, body);
    }

    // ------------------------------------------------------------ setup

    async newSession() {
        const prefs = {
            // See EXTENSION_UUID above. The pref is a string pref whose
            // value is itself JSON.
            "extensions.webextensions.uuids": JSON.stringify({
                [EXTENSION_ID]: EXTENSION_UUID,
            }),
        };

        const value = await this.send("POST", "/session", {
            capabilities: {
                alwaysMatch: {
                    browserName: "firefox",
                    "moz:firefoxOptions": {
                        binary: FIREFOX_BIN,
                        args: [
                            "-headless",
                            // Mandatory on Firefox 153: without it,
                            // navigating to moz-extension:// and running
                            // chrome-context script both fail with
                            // "unsupported operation".
                            //
                            // It grants the driver FULL CHROME PRIVILEGES
                            // over this browser. Acceptable only because
                            // the browser is a throwaway in a CI
                            // container; never point a session with this
                            // flag at anything you care about.
                            "-remote-allow-system-access",
                        ],
                        prefs,
                    },
                },
            },
        });
        this.sessionId = value.sessionId;
        await this.session("POST", "/timeouts", { script: SCRIPT_TIMEOUT_MS });
        return value;
    }

    // Installs the unpacked MV2 build straight from a directory.
    // temporary:true bypasses signature checks, so no XPI and no signing
    // are involved, and the add-on dies with the profile.
    async installAddon(dir) {
        return this.session("POST", "/moz/addon/install", {
            path: dir,
            temporary: true,
        });
    }

    // Classic navigation on purpose. BiDi's browsingContext.navigate
    // refuses moz-extension:// URLs outright.
    async navigate(url) {
        await this.session("POST", "/url", { url });
    }

    async quit() {
        if (this.sessionId) {
            await this.session("DELETE", "").catch(() => {});
            this.sessionId = null;
        }
        this.proc.kill("SIGTERM");
    }

    // ---------------------------------------------------------- scripts

    async setContext(context) {
        if (this.context === context) return;
        await this.session("POST", "/moz/context", { context });
        this.context = context;
    }

    async execute(script, args = []) {
        await this.setContext("content");
        return this.session("POST", "/execute/sync", { script, args });
    }

    // Runs in the privileged chrome scope, where Services and Ci exist.
    async executeChrome(script, args = []) {
        await this.setContext("chrome");
        try {
            return await this.session("POST", "/execute/sync", {
                script,
                args,
            });
        } finally {
            await this.setContext("content");
        }
    }

    // ------------------------------------------------------- page waits

    // Polls a content-context expression until it returns truthy. Every
    // wait in the suite goes through here so a timeout always says which
    // condition it was waiting on rather than "timed out".
    async waitFor(what, script, args = [], timeout = DEFAULT_WAIT_MS) {
        const deadline = Date.now() + timeout;
        let last = null;
        for (;;) {
            try {
                const v = await this.execute(script, args);
                if (v) return v;
                last = null;
            } catch (e) {
                // A navigation or view swap in flight makes execute
                // throw; that is a not-yet, not a failure, until the
                // deadline says otherwise.
                last = e.message;
            }
            if (Date.now() >= deadline) {
                throw new Error(
                    "timed out after " +
                        timeout +
                        "ms waiting for " +
                        what +
                        (last ? " (last error: " + last + ")" : ""),
                );
            }
            await sleep(POLL_INTERVAL_MS);
        }
    }

    // Shown means shown: in the popup a view is switched by toggling a
    // "hidden" class, and an element that is present but collapsed is not
    // the thing a test means by visible.
    async waitVisible(selector, timeout = DEFAULT_WAIT_MS) {
        return this.waitFor(
            "selector " + selector + " to be visible",
            `const el = document.querySelector(arguments[0]);
             if (!el) return false;
             const r = el.getBoundingClientRect();
             return r.width > 0 && r.height > 0;`,
            [selector],
            timeout,
        );
    }

    async isVisible(selector) {
        return this.execute(
            `const el = document.querySelector(arguments[0]);
             if (!el) return false;
             const r = el.getBoundingClientRect();
             return r.width > 0 && r.height > 0;`,
            [selector],
        );
    }

    async count(selector) {
        return this.execute(
            "return document.querySelectorAll(arguments[0]).length;",
            [selector],
        );
    }

    async text(selector) {
        return this.execute(
            `const el = document.querySelector(arguments[0]);
             return el ? el.textContent : null;`,
            [selector],
        );
    }

    async title() {
        return this.session("GET", "/title");
    }

    // The id of the view element currently on top, which is what a
    // failing step needs to report: "the screen did not change" is only
    // useful if it says which screen it stayed on.
    async currentView() {
        return this.execute(
            `const views = document.querySelectorAll('[id^="view-"]');
             for (const v of views) {
                 const r = v.getBoundingClientRect();
                 if (r.width > 0 && r.height > 0) return v.id;
             }
             return null;`,
        );
    }

    // ----------------------------------------------------- interactions

    async findElement(selector) {
        const value = await this.session("POST", "/element", {
            using: "css selector",
            value: selector,
        });
        const ref = value && value[WEB_ELEMENT_KEY];
        if (typeof ref !== "string") {
            throw new Error(
                "no " +
                    WEB_ELEMENT_KEY +
                    " in the element response for " +
                    selector +
                    ": " +
                    JSON.stringify(value),
            );
        }
        return ref;
    }

    // Real WebDriver clicks and real key events rather than in-page
    // .click() and value assignment: the popup's handlers are wired to
    // events, and synthesising them from inside the page would test the
    // harness's idea of the UI instead of the UI.
    async click(selector) {
        await this.waitVisible(selector);
        const id = await this.findElement(selector);
        await this.session("POST", "/element/" + id + "/click", {});
    }

    async fill(selector, value) {
        await this.waitVisible(selector);
        const id = await this.findElement(selector);
        await this.session("POST", "/element/" + id + "/clear", {});
        await this.session("POST", "/element/" + id + "/value", {
            text: String(value),
        });
    }

    async value(selector) {
        return this.execute(
            `const el = document.querySelector(arguments[0]);
             return el ? el.value : null;`,
            [selector],
        );
    }
}

// ------------------------------------------------------- error capture

// Uncaught errors from extension code, read out of the privileged console
// service.
//
// This is not the obvious mechanism, and the obvious one does not work:
// WebDriver BiDi's log.entryAdded delivers NOTHING for extension pages.
// Verified on Firefox 142 and 153 against a same-session control — a plain
// http:// page yields uncaught errors with stack traces, the
// moz-extension:// popup yields zero events, because the remote agent
// excludes extension browsing contexts from BiDi observation. A harness
// built on Playwright-BiDi or Puppeteer-BiDi therefore sees nothing and
// reports success. Do not "simplify" this back to BiDi.
//
// nsIConsoleService is not per-page: it also carries errors from the
// background page, which BiDi would not have covered even if it worked.
// Background-page capture is verified by probe — a throw at the top of
// src/background/index.js, which kills the background page outright, fails
// the run. Content-script errors should arrive by the same route, but that
// is UNVERIFIED here and must not be claimed: the container runs with
// --network none, so there is no http:// page for a content script to be
// injected into and this suite never exercises one.
//
// Warnings are excluded so the semantics match Playwright's pageerror:
// uncaught errors only.
//
// The read and the clear are ONE chrome script on purpose. Splitting them
// into two round trips leaves a blind window between them in which an
// error is logged into a buffer that is about to be discarded, and is
// destroyed unread rather than deferred to the next drain. That was not
// theoretical: with a separate reset() call, a probe of 100 sequenced
// throws at 20ms spacing lost one of them outright.
const DRAIN_ERRORS_SCRIPT = `
    const origin = arguments[0];
    const out = [];
    for (const raw of Services.console.getMessageArray() || []) {
        let e;
        try {
            e = raw.QueryInterface(Ci.nsIScriptError);
        } catch (_) {
            continue;
        }
        if (e.flags & Ci.nsIScriptError.warningFlag) continue;
        const src = e.sourceName || "";
        if (!src.startsWith(origin)) continue;
        out.push({
            msg: e.errorMessage,
            src: src,
            line: e.lineNumber,
            cat: e.category,
        });
    }
    Services.console.reset();
    return out;
`;

class ConsoleErrors {
    constructor(driver, originPrefix) {
        this.driver = driver;
        this.originPrefix = originPrefix;
    }

    // Everything logged since the last take, read and cleared atomically
    // in a single chrome round trip. Poll-based, so an error is attributed
    // to the step that was running when it was drained, not to the moment
    // inside that step at which it happened — see the limitation note in
    // run.js. An error that arrives mid-drain is not lost — it makes this
    // batch or the next one — but the console service ring buffer holds
    // only 250 messages, so more than that between two takes evicts the
    // oldest unread. A clean run peaks at 4.
    async take() {
        const found = await this.driver.executeChrome(DRAIN_ERRORS_SCRIPT, [
            this.originPrefix,
        ]);
        return found || [];
    }
}

// ------------------------------------------------------------- startup

async function waitForDriverReady(base, timeoutMs) {
    const deadline = Date.now() + timeoutMs;
    for (;;) {
        try {
            const res = await fetch(base + "/status");
            if (res.ok) {
                const body = await res.json();
                if (body && body.value && body.value.ready !== false) return;
            }
        } catch {
            // not listening yet
        }
        if (Date.now() >= deadline) {
            throw new Error(
                "geckodriver did not become ready within " + timeoutMs + "ms",
            );
        }
        await sleep(POLL_INTERVAL_MS);
    }
}

async function start() {
    const port = await freePort();
    const proc = spawn(
        GECKODRIVER,
        ["--port", String(port), "--host", "127.0.0.1"],
        { stdio: ["ignore", "inherit", "inherit"] },
    );
    proc.on("error", (e) => {
        console.error("geckodriver failed to spawn: " + e.message);
    });

    const base = "http://127.0.0.1:" + port;
    try {
        await waitForDriverReady(base, 30000);
    } catch (e) {
        proc.kill("SIGKILL");
        throw e;
    }
    return new Driver(proc, base);
}

module.exports = {
    ConsoleErrors,
    Driver,
    EXTENSION_ID,
    EXTENSION_ORIGIN,
    EXTENSION_UUID,
    start,
    sleep,
};