// Where a sheet puts the dealer, and whether they can get anywhere from there.
//
// Modal exists because six overlays were each missing the same three things, and it
// fixed all six at once by answering one question the same way everywhere: focus the
// first control, and hold Tab between the first and the last. Measured this round, that
// single answer had gone wrong in three separate directions.
//
// It could not see a <summary>. The rulings sheet is twelve of them and one Done
// button, so the trap decided Done was both ends of the ring and bounced every press
// back to it: eighty Tab presses, one element ever reached, twelve rulings that could
// not be opened without a mouse.
//
// "The first control" was the card picker's Clear. The sheet a dealer opens to write a
// card down opened on the button that rubs one out — the one thing the APG says to keep
// a dialog off. And "the first control" is not an answer six dialogs share: Roselli's
// rule is that a dialog long enough to scroll should land on its heading so the reader
// can orient, and a short question with one irreversible answer should land on the
// answer that leaves them no worse off.
//
// And a sheet that redraws itself was deleting the control that held focus. Choosing a
// buy-in, picking a card, switching slots, confirming a side pot: all four left focus on
// the document body, which inside a modal is nowhere at all.
const test = require("node:test");
const { describe } = require("node:test");
const assert = require("node:assert");
const fs = require("fs");
const path = require("path");
const { Modal, CardPicker } = require("./load");

const ROOT = path.join(__dirname, "..", "..", "JoshHeaps.Net");
const PAGE = fs.readFileSync(path.join(ROOT, "Pages", "Casino", "TexasHoldem.cshtml"), "utf8");
const CSS = fs.readFileSync(path.join(ROOT, "wwwroot", "css", "casino", "holdem.css"), "utf8");
const src = name => fs.readFileSync(
    path.join(ROOT, "wwwroot", "js", "casino", "holdem", `${name}.js`), "utf8");

// The markup of one overlay, from its opening div to the next one's.
const OVERLAY_ORDER = ["addChipsOverlay", "rulingsOverlay", "seatMenuOverlay",
    "cardPickerOverlay", "confirmOverlay", "potWizardOverlay"];
const overlay = id => {
    const at = PAGE.indexOf(`<div id="${id}"`);
    assert.ok(at >= 0, `there is no ${id}`);
    const ends = OVERLAY_ORDER
        .map(other => PAGE.indexOf(`<div id="${other}"`, at + 1))
        .filter(i => i > at);
    return PAGE.slice(at, ends.length ? Math.min(...ends) : PAGE.length);
};

// A document small enough to answer the handful of questions these functions ask of
// one, and honest about the two that matter: a detached node knows it is detached, and
// a disabled button refuses focus.
function fakeSheet(specs) {
    const doc = { activeElement: null };
    const nodes = specs.map(spec => ({
        dataset: spec.key === undefined ? {} : { focusKey: spec.key },
        disabled: !!spec.disabled,
        isConnected: true,
        tabIndex: 0,
        label: spec.key || spec.label,
        focus() {
            if (this.disabled) return;
            doc.activeElement = this;
        },
    }));
    const root = {
        nodes,
        contains: el => nodes.includes(el),
        querySelectorAll: () => nodes.filter(n => n.dataset.focusKey !== undefined),
    };
    return { doc, root, nodes };
}

// preservingFocus and the picker's cursor both reach for the global document. They are
// given one for the length of a test and it is taken away again afterwards.
function withDocument(doc, body) {
    const had = Object.prototype.hasOwnProperty.call(globalThis, "document");
    const before = globalThis.document;
    globalThis.document = doc;
    try {
        return body();
    } finally {
        if (had) globalThis.document = before;
        else delete globalThis.document;
    }
}

// ---------------------------------------------------------------------------

describe("what counts as somewhere you can Tab to", () => {
    const selectors = Modal.FOCUSABLE.split(",");

    // The whole of the rulings sheet hung on this one omission.
    test("a summary is a control, because the browser already treats it as one", () => {
        assert.ok(selectors.some(s => /details\s*>\s*summary/.test(s)),
            "a <details> summary is focusable without a tabindex, and this list can't see it");
    });

    // Left off, a card taken out of the Tab order still matches `button`, and the grid
    // goes back to being fifty-two stops with a roving tabindex painted on top.
    test("every line excludes what has been taken out of the Tab order, not just the last", () => {
        selectors.forEach(selector => {
            assert.ok(/:not\(\[tabindex="-1"\]\)/.test(selector) || /^\s*\[tabindex\]/.test(selector),
                `\`${selector.trim()}\` still matches controls that are not Tab stops`);
        });
    });

    test("and the sheet itself is still off the list", () => {
        assert.ok(/\[tabindex\]:not\(\[tabindex="-1"\]\)/.test(Modal.FOCUSABLE));
    });
});

describe("where each sheet lands the dealer", () => {
    const LANDS_ON_ITS_HEADING = [
        ["cardPickerOverlay", "cardPickerTitle"],
        ["addChipsOverlay", "addChipsTitle"],
        ["rulingsOverlay", "rulingsTitle"],
        ["potWizardOverlay", "potWizardTitle"],
        ["seatMenuOverlay", "seatMenuTitle"],
    ];

    LANDS_ON_ITS_HEADING.forEach(([id, heading]) => {
        test(`${id} opens on the line that says which`, () => {
            const markup = overlay(id);
            const tag = markup.match(new RegExp(`<h2 id="${heading}"[^>]*>`));
            assert.ok(tag, `${heading} is not an h2 in ${id}`);
            assert.match(tag[0], /data-modal-focus/);
            assert.match(tag[0], /tabindex="-1"/,
                "a heading that is a Tab stop is a Tab stop the dealer has to press past");
        });
    });

    // The APG's own example of when to land on a control rather than a heading, and the
    // reason: one of the two answers cannot be taken back.
    test("the confirm dialog is the exception, and it lands on Cancel", () => {
        const markup = overlay("confirmOverlay");
        const cancel = markup.match(/<button id="confirmCancelBtn"[^>]*>/);
        assert.ok(cancel);
        assert.match(cancel[0], /data-modal-focus/);
        assert.ok(!/<button id="confirmAcceptBtn"[^>]*data-modal-focus/.test(markup),
            "the dialog lands on the answer that cannot be taken back");
    });

    test("no sheet names two landing spots, which would be a coin toss", () => {
        OVERLAY_ORDER.forEach(id => {
            const found = (overlay(id).match(/data-modal-focus/g) || []).length;
            assert.equal(found, 1, `${id} names ${found} landing spots`);
        });
    });

    test("the card picker no longer opens on Clear", () => {
        const markup = overlay("cardPickerOverlay");
        assert.ok(markup.indexOf('id="cardPickerTitle"') < markup.indexOf('id="cardPickerClearBtn"'),
            "the heading has moved below the button it was there to keep focus off");
        assert.ok(!/id="cardPickerClearBtn"[^>]*data-modal-focus/.test(markup));
    });

    // The landing spot is deliberately outside the ring, and a wrap that only knows
    // "is this the first one" walks straight out of the dialog on the first Shift+Tab.
    test("the trap wraps from outside the ring as well as from its ends", () => {
        const modal = src("modal");
        const at = modal.indexOf("const at = focusable.indexOf(");
        assert.ok(at >= 0, "the Tab trap no longer asks where the dealer is in the ring");
        const body = modal.slice(at, modal.indexOf("\n    },", at));
        assert.match(body, /shiftKey && at <= 0/);
        assert.match(body, /at === -1/);
    });
});

describe("a redraw that does not drop the dealer", () => {
    test("focus comes back to the control with the same name", () => {
        const { doc, root, nodes } = fakeSheet([
            { key: "quick-500" }, { key: "quick-1000" }, { key: "quick-2000" }]);
        doc.activeElement = nodes[1];

        withDocument(doc, () => Modal.preservingFocus(root, () => {
            // What a rebuild does: the old buttons go, identical new ones arrive.
            nodes.forEach(n => { n.isConnected = false; });
            root.nodes = root.querySelectorAll = null;
            const rebuilt = fakeSheet([{ key: "quick-500" }, { key: "quick-1000" }, { key: "quick-2000" }]);
            rebuilt.nodes.forEach(n => { n.focus = () => { doc.activeElement = n; }; });
            root.querySelectorAll = () => rebuilt.nodes;
            root.contains = el => rebuilt.nodes.includes(el);
        }));

        assert.equal(doc.activeElement.dataset.focusKey, "quick-1000");
    });

    // The card just picked is a dealt card now, and a dealt card is a disabled button.
    // There is no coming back to it, so the caller is asked where to go instead.
    test("a name that comes back disabled hands the decision to the caller", () => {
        const { doc, root, nodes } = fakeSheet([{ key: "AS" }, { key: "KH" }]);
        doc.activeElement = nodes[0];
        let asked = false;

        withDocument(doc, () => Modal.preservingFocus(root, () => {
            nodes[0].isConnected = false;
            nodes[0].disabled = true;
        }, () => { asked = true; }));

        assert.ok(asked, "focus was left on the body of a modal");
    });

    test("and a name that is simply gone asks too", () => {
        const { doc, root, nodes } = fakeSheet([{ key: "confirm" }]);
        doc.activeElement = nodes[0];
        let asked = false;

        withDocument(doc, () => Modal.preservingFocus(root, () => {
            nodes[0].isConnected = false;
            root.querySelectorAll = () => [];
        }, () => { asked = true; }));

        assert.ok(asked);
    });

    // Clear is in the header. Nothing rebuilds it, so nothing should move it — a redraw
    // the dealer asked for is not a reason to take them somewhere else.
    test("a control that survived the redraw is left exactly where it was", () => {
        const { doc, root, nodes } = fakeSheet([{ label: "Clear" }, { key: "AS" }]);
        doc.activeElement = nodes[0];
        let asked = false;

        withDocument(doc, () => Modal.preservingFocus(root, () => {
            nodes[1].isConnected = false;
        }, () => { asked = true; }));

        assert.equal(doc.activeElement, nodes[0]);
        assert.ok(!asked);
    });

    test("and a dealer who was never in this sheet is not dragged into it", () => {
        const { doc, root } = fakeSheet([{ key: "AS" }]);
        const elsewhere = { dataset: {}, isConnected: true };
        doc.activeElement = elsewhere;
        let asked = false;

        withDocument(doc, () => Modal.preservingFocus(root, () => {}, () => { asked = true; }));

        assert.equal(doc.activeElement, elsewhere);
        assert.ok(!asked);
    });

    // Four sheets redraw themselves on a tap. All four go through this now, and each
    // one hands over the piece of itself it is about to throw away.
    [["addChips", "render()", "addChipsSheet"],
     ["cardPicker", "render()", "cardPickerSheet"],
     ["seatMenu", "render()", "seatMenuOverlay"],
     ["potWizard", "renderStepInto()", "potWizardModal"]].forEach(([module, method, root]) => {
        test(`${module}'s ${method} redraws through it`, () => {
            const text = src(module);
            const at = text.indexOf(`\n    ${method} {`);
            assert.ok(at >= 0, `${module} has no ${method}`);
            const body = text.slice(at, text.indexOf("\n    },", at));
            assert.match(body, /Modal\.preservingFocus\(/,
                `${module} rebuilds its controls without saying what to do about focus`);
            assert.ok(body.includes(`"${root}"`),
                `${module} hands preservingFocus something other than ${root}`);
        });
    });
});

describe("thirteen cards, one Tab stop", () => {
    test("the deck is written once, ace down to two", () => {
        const deck = CardPicker.deck();
        assert.equal(deck.length, 52);
        assert.equal(new Set(deck.map(c => c.card)).size, 52);
        assert.deepEqual(deck.slice(0, 4).map(c => c.card), ["AS", "AH", "AD", "AC"]);
        assert.equal(deck[4].card, "KS");
        assert.equal(deck[51].card, "2C");
    });

    // A dealt card is `aria-disabled` rather than `disabled`, so it holds focus like any
    // other cell — which is what lets the arrows tell the truth about the grid, and what
    // lets pressing one be answered instead of ignored. See theUnansweredPress.
    const grid = keys => keys.map(key => ({
        dataset: { focusKey: key.replace("!", "") },
        getAttribute: name => (name === "aria-disabled" && key.includes("!") ? "true" : null),
        tabIndex: 0,
        focus() {},
    }));

    const withGrid = (cards, body) => {
        const nodes = grid(cards);
        return withDocument({ querySelectorAll: () => nodes }, () => body(nodes));
    };

    test("a step is one card, whether or not that card is already out", () => {
        // The seven is dealt. Stepping along from the eight lands on it and says so,
        // rather than quietly arriving at the six.
        withGrid(["8C", "7C!", "6C"], () => {
            assert.equal(CardPicker.nextCursor(0, 1), 1);
        });
    });

    // The whole reason the skipping had to go. Hunting for the next card that could take
    // focus did the exact thing the no-wrap rule below was written to prevent: it moved
    // the dealer sideways without being asked. Right from the ace over a dealt king
    // landed on the queen, so the column silently became the one to its right, and the
    // next press of Down walked a rank nobody had asked for.
    test("and it never slides the dealer into a column they didn't ask for", () => {
        withGrid(["AS", "KS!", "QS", "JS", "TS", "9S", "8S", "7S"], () => {
            const afterRight = CardPicker.nextCursor(0, 1);
            assert.equal(afterRight, 1, "a dealt king is still the cell to the right of the ace");
            assert.equal(CardPicker.nextCursor(afterRight, 4), 5,
                "and down a row of four from it is the nine, four ranks along");
        });
    });

    // Wrapping would answer "move me down a row" by moving the dealer to the other end
    // of the grid, which is not what they asked and not where they would look.
    test("the edge of the grid is the edge, not a way round to the other side", () => {
        withGrid(["AS", "KS", "QS", "JS"], () => {
            assert.equal(CardPicker.nextCursor(3, 1), 3);
            assert.equal(CardPicker.nextCursor(0, -1), 0);
        });
    });

    test("only one card is in the Tab order at a time", () => {
        withGrid(["AS", "KS", "QS", "JS"], nodes => {
            CardPicker.aimCursor(2);
            assert.deepEqual(nodes.map(n => n.tabIndex), [-1, -1, 0, -1]);
        });
    });

    // Which happens after every pick: the cursor is sitting on a card that has just
    // become a dealt card. It stays there, because that cell is still a cell and its
    // neighbours are still where they were a moment ago.
    test("a cursor left on a dealt card stays on it", () => {
        withGrid(["AS!", "KS", "QS", "JS"], nodes => {
            CardPicker.aimCursor(0);
            assert.equal(CardPicker.cursor, 0);
            assert.deepEqual(nodes.map(n => n.tabIndex), [0, -1, -1, -1]);
        });
    });

    test("and a grid with nothing left in it still has somewhere to put the cursor", () => {
        withGrid(["5S!", "4S!", "3S!", "2S!"], nodes => {
            CardPicker.aimCursor(3);
            assert.equal(CardPicker.cursor, 3);
            assert.deepEqual(nodes.map(n => n.tabIndex), [-1, -1, -1, 0]);
        });
    });

    // An index from outside the grid is clamped rather than wrapped, which is what
    // Home and End lean on: they ask for one card past either end and take what they
    // are given.
    test("Home and End ask past the ends and land on them", () => {
        withGrid(["AS", "KS", "QS", "JS"], () => {
            assert.equal(CardPicker.nextCursor(-1, 1), 0);
            assert.equal(CardPicker.nextCursor(4, -1), 3);
        });
    });

    // It used to step by `SUITS.length`, because the grid was four suits wide at every
    // size. The grid is thirteen ranks of one suit now and takes as many columns as the
    // width holds — five on a 360px phone, seven at 460 — so a constant would be wrong
    // on most screens, which is the thing that slid the cursor into the wrong column
    // the last time these two disagreed. It asks the layout instead.
    test("the arrows step by the row the grid actually has, not by a guess", () => {
        const picker = src("cardPicker");
        const at = picker.indexOf("onGridKey(event)");
        assert.ok(at >= 0, "the grid has no arrow keys");
        const body = picker.slice(at, picker.indexOf("\n    },", at));
        assert.match(body, /const stride = this\.gridStride\(\)/);
        assert.match(body, /ArrowRight: 1.*ArrowLeft: -1.*ArrowDown: stride.*ArrowUp: -stride/s);
        assert.match(body, /"Home"/);
        assert.match(body, /"End"/);
    });

    test("and the row it actually has is read off the grid", () => {
        const picker = src("cardPicker");
        const at = picker.indexOf("gridStride() {");
        assert.ok(at >= 0, "there is no gridStride");
        const body = picker.slice(at, picker.indexOf("\n    },", at));
        assert.match(body, /getComputedStyle\(grid\)\.gridTemplateColumns/);
        // Outside a browser there is nothing to measure, and thirteen ranks in one row
        // is the shape that makes Up and Down do nothing rather than something wrong.
        assert.match(body, /return this\.RANKS\.length/);
    });

    test("a fresh sheet starts at the top of the deck", () => {
        const picker = src("cardPicker");
        ["open(state, hooks, seatIndex, cardIndex) {", "openBoard(state, hooks, cardIndex, limit = 5) {"]
            .forEach(signature => {
                const at = picker.indexOf(signature);
                assert.ok(at >= 0, `there is no \`${signature}\``);
                assert.match(picker.slice(at, picker.indexOf("this.render();", at)), /this\.cursor = 0;/);
            });
    });
});

describe("seeing where you are", () => {
    // Until a summary could be Tabbed to at all, there was no way to notice that
    // twenty of them had no ring.
    test("a summary gets the tool's own focus ring, not the browser's", () => {
        const at = CSS.indexOf("---------- Keyboard focus ----------");
        assert.ok(at >= 0);
        const block = CSS.slice(at, CSS.indexOf("outline: 2px solid #7fc4ff", at));
        assert.match(block, /(^|\n)summary:focus-visible,/);
    });

    // Only script ever focuses these, so `:focus` would ring the title of every sheet
    // on a phone that has no keyboard to ring it for.
    test("the landing heading rings for a keyboard and stays quiet for a thumb", () => {
        const at = CSS.indexOf('h2[data-modal-focus]:focus-visible {');
        assert.ok(at >= 0, "the heading a sheet lands on shows nothing when it takes focus");
        const rule = CSS.slice(at, CSS.indexOf("}", at));
        assert.match(rule, /outline: 2px solid #7fc4ff/);
        // These headings run to the edge of their sheet; an outward ring is clipped.
        assert.match(rule, /outline-offset: -2px/);
        assert.ok(!/\[data-modal-focus\]:focus\b(?!-)/.test(CSS),
            "a plain :focus rule would ring the title on every tap");
    });
});