pragma Singleton

// The fingerprint reader, for the Users page.
//
// Two facts, owned by two different systems: fprintd holds the enrolled prints,
// and authselect decides whether PAM asks the reader at unlock. Both come
// through scripts/panama-fingerprint, and the one privileged change -- flipping
// authselect's with-fingerprint feature -- prompts through polkit with a stated
// reason, like everything else on that page.
//
// The two facts are kept apart deliberately. `unlockFeatureEnabled` is a
// property of the PAM configuration and is reported whether or not a reader
// exists, because the state worth seeing most is the one where the feature is
// on and the reader is gone: nothing works, nothing says why, and the switch
// that would fix it used to be hidden behind the missing hardware. Hence
// `cardVisible`.
//
// Enrollment happens here now rather than in GNOME's Users panel. The helper
// drives fprintd's own Claim/EnrollStart cycle and prints one line of JSON per
// touch, which is what `enrollStage of enrollTotal` counts.
//
// Read when the page opens rather than at shell startup: probing fprintd
// bus-activates the daemon, and most sessions never open this page.

import Quickshell
import Quickshell.Io
import QtQuick

Singleton {
    id: root

    readonly property string helperPath: Quickshell.shellDir + "/scripts/panama-fingerprint"

    property bool readerPresent: false
    property string readerName: ""
    // The fingers fprintd currently holds a print for, by fprintd's own names.
    property var fingers: []
    property bool unlockFeatureEnabled: false
    property bool scanned: false
    property string lastError: ""

    // Guards read the Process objects; this is only for the page to bind to.
    readonly property bool busy: apply.running || change.running

    // The card is worth drawing when there is a reader OR when PAM has been
    // told to use one. The second half is the stuck state: no reader, nothing
    // enrolled, and a feature switched on that quietly slows every unlock down.
    readonly property bool cardVisible: root.readerPresent || root.unlockFeatureEnabled

    // ── What a finger is called ──────────────────────────────────────────────
    //
    // fprintd's vocabulary lives here and only here, so nothing can disagree
    // about what a finger is named or how it reads.

    readonly property var allFingers: [
        "right-index-finger", "right-middle-finger", "right-ring-finger",
        "right-little-finger", "right-thumb",
        "left-index-finger", "left-middle-finger", "left-ring-finger",
        "left-little-finger", "left-thumb"
    ]

    // The ones still worth offering: enrolling a finger twice replaces the
    // print rather than adding one, which is not what "Add a fingerprint" says.
    readonly property var availableFingers:
        root.allFingers.filter(finger => root.fingers.indexOf(finger) === -1)

    // "right-index-finger" -> "Right index finger". Presentation lives here
    // rather than in the page, the way PowerProfiles.label does.
    function fingerLabel(finger: string): string {
        const words = String(finger).split("-").join(" ");
        return words.slice(0, 1).toUpperCase() + words.slice(1);
    }

    // ── Enrollment ───────────────────────────────────────────────────────────

    property bool enrolling: false
    // Touches taken, of touches the reader wants. Both zero until the device
    // has said how many it needs.
    property int enrollStage: 0
    property int enrollTotal: 0
    // The finger being enrolled, and fprintd's last word about the last touch
    // ("enroll-stage-passed", "enroll-retry-scan-too-short", ...). The page
    // turns the retries into "Try again, a little slower".
    property string enrollFinger: ""
    property string enrollResult: ""
    // claiming | scanning | done | failed | cancelled
    property string enrollPhase: ""

    function refresh(): void {
        if (!query.running)
            query.running = true;
    }

    function setUnlockEnabled(on: bool): void {
        if (apply.running)
            return;
        root.lastError = "";
        apply.command = [root.helperPath, "set-unlock", on ? "on" : "off"];
        apply.running = true;
    }

    function startEnroll(finger: string): void {
        if (enroll.running)
            return;
        root.lastError = "";
        root.enrollFinger = finger;
        root.enrollStage = 0;
        root.enrollTotal = 0;
        root.enrollResult = "";
        root.enrollPhase = "claiming";
        root.enrolling = true;
        enroll.command = [root.helperPath, "enroll", finger];
        enroll.running = true;
    }

    // Stopping the process is the cancellation: the helper catches the signal,
    // stops the enrollment and releases the reader, which is the part that
    // matters -- a claimed device belonging to a dead process refuses the next
    // attempt.
    function cancelEnroll(): void {
        if (enroll.running)
            enroll.running = false;
    }

    function removeFinger(finger: string): void {
        if (change.running)
            return;
        root.lastError = "";
        change.command = [root.helperPath, "remove", finger];
        change.running = true;
    }

    function removeAll(): void {
        if (change.running)
            return;
        root.lastError = "";
        change.command = [root.helperPath, "remove-all"];
        change.running = true;
    }

    // Every verb that reports state answers in the same shape, so there is one
    // place that reads it.
    function absorb(text: string): void {
        try {
            const parsed = JSON.parse(text);
            root.readerPresent = parsed.reader === true;
            root.readerName = String(parsed.readerName ?? "");
            root.fingers = Array.isArray(parsed.enrolled) ? parsed.enrolled : [];
            root.unlockFeatureEnabled = parsed.unlockFeatureEnabled === true;
            if (String(parsed.error ?? "") !== "")
                root.lastError = String(parsed.error);
        } catch (error) {
            root.readerPresent = false;
            root.lastError = "Could not read the fingerprint helper's output.";
            console.warn("Fingerprint: could not parse helper output:", error);
        }
        root.scanned = true;
    }

    Process {
        id: query
        command: [root.helperPath, "status"]
        stdout: StdioCollector { onStreamFinished: root.absorb(this.text) }
    }

    Process {
        id: apply
        stderr: StdioCollector {
            // A dismissed polkit prompt is a normal outcome on this page, not
            // a failure to report.
            onStreamFinished: {
                const text = this.text.trim();
                if (text !== "" && !/dismissed|not authorized/i.test(text))
                    root.lastError = text;
            }
        }
        // Re-read rather than assuming: authselect may refuse, and the
        // prompt may have been dismissed.
        onExited: root.refresh()
    }

    Process {
        id: change
        // Removing answers with the fresh state, so the list updates from the
        // removal itself and never has to ask again.
        stdout: StdioCollector { onStreamFinished: root.absorb(this.text) }
    }

    Process {
        id: enroll
        stdout: SplitParser {
            // One JSON object per touch. A reader takes five or so, seconds
            // apart, so this is a trickle rather than a stream to drain.
            onRead: line => {
                try {
                    const update = JSON.parse(line);
                    root.enrollPhase = String(update.stage ?? root.enrollPhase);
                    root.enrollTotal = Number(update.total ?? root.enrollTotal);
                    root.enrollStage = Number(update.done ?? root.enrollStage);
                    root.enrollResult = String(update.result ?? "");
                    if (update.ok === false)
                        root.lastError = String(update.error ?? "That finger could not be enrolled.");
                } catch (error) {
                    // A line that is not JSON is not worth abandoning an
                    // enrollment over; the exit status is what decides.
                }
            }
        }
        onExited: {
            root.enrolling = false;
            // Cancelled by stopping the process: the helper had no chance to
            // say anything, and there is nothing to report.
            if (root.enrollPhase !== "done" && root.enrollPhase !== "failed")
                root.enrollPhase = "cancelled";
            root.refresh();
        }
    }
}