// @ts-check
/**
 * Vertical Tabs — the tab list.
 *
 * The extension owns the tab state; this renders it and posts back intents. Nothing
 * here is authoritative, so a stale row cannot act on the wrong tab: every message
 * carries the row id and the extension resolves it against live tab state.
 */
(function () {
    'use strict';

    const vscode = acquireVsCodeApi();

    /** @type {{rows: any[], showProject: boolean, showDirectory: boolean, showColumn: boolean}} */
    let data = { rows: [], showProject: false, showDirectory: false, showColumn: false };
    let selectedId = (vscode.getState() || {}).selectedId;

    const el = {
        list: /** @type {HTMLElement} */ (document.getElementById('list')),
        empty: /** @type {HTMLElement} */ (document.getElementById('empty')),
        menu: /** @type {HTMLElement} */ (document.getElementById('menu')),
    };

    const ICONS = {
        close: '<svg viewBox="0 0 16 16"><path d="M8 8.707l3.646 3.647.708-.707L8.707 8l3.647-3.646-.707-.708L8 7.293 4.354 3.646l-.708.708L7.293 8l-3.647 3.646.708.708L8 8.707z"/></svg>',
        pin: '<svg viewBox="0 0 16 16"><path d="M10.5 1.5l4 4-2 1-1.5 1.5.5 3.5-1 1-3-3-3.5 3.5-1-1L6.5 9l-3-3 1-1 3.5.5L9.5 4l1-2.5z"/></svg>',
    };

    function saveState() {
        vscode.setState({ selectedId });
    }

    /** Splits `Foo.Bar.cs` into stem and extension so the extension never ellipsizes. */
    function splitName(label) {
        const dot = label.lastIndexOf('.');
        return dot > 0 ? [label.slice(0, dot), label.slice(dot)] : [label, ''];
    }

    function iconButton(className, svg, title, onClick) {
        const button = document.createElement('button');
        button.className = `marker ${className}`;
        button.innerHTML = svg;
        button.title = title;
        button.tabIndex = -1;
        button.addEventListener('click', event => {
            event.stopPropagation();
            onClick();
        });
        return button;
    }

    function rowElement(row) {
        const div = document.createElement('div');
        div.className = 'tab';
        div.dataset.id = row.id;
        div.setAttribute('role', 'option');
        if (row.isActive) {
            div.classList.add('active');
        }
        if (row.id === selectedId) {
            div.classList.add('selected');
        }
        if (row.isDirty) {
            div.classList.add('is-dirty');
        }
        if (row.isPreview) {
            div.classList.add('preview');
        }
        if (!row.canActivate) {
            div.classList.add('inert');
        }
        // The border colour is the contributed theme colour, so a user override in
        // workbench.colorCustomizations still applies.
        if (row.colorIndex > 0) {
            div.style.setProperty('--tab-color', `var(--vscode-verticalTabs-project${row.colorIndex})`);
        } else if (row.uri) {
            div.style.setProperty('--tab-color', 'var(--vscode-verticalTabs-noProject)');
        }

        div.appendChild(iconButton('pin', ICONS.pin, row.isPinned ? 'Unpin' : 'Pin',
            () => vscode.postMessage({ type: 'togglePin', id: row.id })));
        if (row.isPinned) {
            /** @type {HTMLElement} */ (div.querySelector('button.pin')).classList.add('on');
        }

        const name = document.createElement('span');
        name.className = 'name';
        const [stem, ext] = splitName(row.label);
        const stemSpan = document.createElement('span');
        stemSpan.className = 'stem';
        stemSpan.textContent = stem;
        name.appendChild(stemSpan);
        if (ext) {
            const extSpan = document.createElement('span');
            extSpan.className = 'ext';
            extSpan.textContent = ext;
            name.appendChild(extSpan);
        }
        div.appendChild(name);

        const trailing = [];
        if (data.showDirectory && row.dir) {
            trailing.push(row.dir);
        }
        if (data.showProject && row.project) {
            trailing.push(row.project);
        }
        if (data.showColumn && row.column) {
            trailing.push(`#${row.column}`);
        }
        if (trailing.length > 0) {
            const dir = document.createElement('span');
            dir.className = 'dir';
            dir.textContent = trailing.join('  ');
            div.appendChild(dir);
        }

        const dirty = document.createElement('span');
        dirty.className = 'marker dirty';
        div.appendChild(dirty);

        div.appendChild(iconButton('close', ICONS.close, 'Close',
            () => vscode.postMessage({ type: 'close', id: row.id })));

        div.title = row.tooltip;
        return div;
    }

    function render() {
        el.list.textContent = '';
        el.empty.hidden = data.rows.length > 0;

        const fragment = document.createDocumentFragment();
        let previousPinned;
        for (const row of data.rows) {
            // A rule under the pinned block, the way a tab bar separates them.
            if (previousPinned === true && !row.isPinned) {
                const rule = document.createElement('div');
                rule.className = 'separator';
                fragment.appendChild(rule);
            }
            previousPinned = row.isPinned;
            fragment.appendChild(rowElement(row));
        }
        el.list.appendChild(fragment);
    }

    // -----------------------------------------------------------------------
    // Selection and keyboard
    // -----------------------------------------------------------------------

    function select(id, reveal) {
        selectedId = id;
        saveState();
        for (const node of el.list.querySelectorAll('.tab')) {
            node.classList.toggle('selected', node.dataset.id === id);
        }
        if (reveal) {
            const node = el.list.querySelector(`.tab[data-id="${CSS.escape(id)}"]`);
            if (node) {
                node.scrollIntoView({ block: 'nearest' });
            }
        }
    }

    function move(delta) {
        if (data.rows.length === 0) {
            return;
        }
        const current = data.rows.findIndex(row => row.id === selectedId);
        const next = Math.max(0, Math.min(data.rows.length - 1,
            current < 0 ? 0 : current + delta));
        select(data.rows[next].id, true);
    }

    el.list.addEventListener('click', event => {
        const row = /** @type {HTMLElement} */ (event.target).closest('.tab');
        if (!row) {
            return;
        }
        select(row.dataset.id, false);
        // A webview tab has no resource to re-open, so asking would silently do nothing.
        if (!row.classList.contains('inert')) {
            vscode.postMessage({ type: 'open', id: row.dataset.id });
        }
    });

    // Middle click closes, the way it does on a tab bar.
    el.list.addEventListener('auxclick', event => {
        if (event.button !== 1) {
            return;
        }
        const row = /** @type {HTMLElement} */ (event.target).closest('.tab');
        if (row) {
            event.preventDefault();
            vscode.postMessage({ type: 'close', id: row.dataset.id });
        }
    });

    el.list.addEventListener('keydown', event => {
        switch (event.key) {
            case 'ArrowDown': move(1); break;
            case 'ArrowUp': move(-1); break;
            case 'Home': move(-data.rows.length); break;
            case 'End': move(data.rows.length); break;
            case 'Enter':
                if (selectedId) {
                    vscode.postMessage({ type: 'open', id: selectedId });
                }
                break;
            case 'Delete':
                if (selectedId) {
                    vscode.postMessage({ type: 'close', id: selectedId });
                }
                break;
            default:
                return;
        }
        event.preventDefault();
    });

    // -----------------------------------------------------------------------
    // Context menu
    // -----------------------------------------------------------------------

    const MENU = [
        { label: 'Close', type: 'close' },
        { label: 'Close Others', type: 'closeOthers' },
        { separator: true },
        { label: 'Pin / Unpin', type: 'togglePin' },
        { separator: true },
        { label: 'Copy Path', type: 'copyPath', needsFile: true },
        { label: 'Reveal in Explorer View', type: 'reveal', needsFile: true },
    ];

    function openMenu(row, x, y) {
        el.menu.textContent = '';
        const hasFile = !!row.uri;
        for (const item of MENU) {
            if (item.separator) {
                const rule = document.createElement('div');
                rule.className = 'menu-separator';
                el.menu.appendChild(rule);
                continue;
            }
            if (item.needsFile && !hasFile) {
                continue;
            }
            const button = document.createElement('button');
            button.textContent = item.label;
            button.addEventListener('click', () => {
                closeMenu();
                vscode.postMessage({ type: item.type, id: row.id });
            });
            el.menu.appendChild(button);
        }

        el.menu.hidden = false;
        // Keep it inside the view.
        const box = el.menu.getBoundingClientRect();
        el.menu.style.left = `${Math.max(0, Math.min(x, window.innerWidth - box.width - 2))}px`;
        el.menu.style.top = `${Math.max(0, Math.min(y, window.innerHeight - box.height - 2))}px`;
        const first = el.menu.querySelector('button');
        if (first) {
            /** @type {HTMLElement} */ (first).focus();
        }
    }

    function closeMenu() {
        el.menu.hidden = true;
    }

    el.list.addEventListener('contextmenu', event => {
        const node = /** @type {HTMLElement} */ (event.target).closest('.tab');
        if (!node) {
            return;
        }
        const row = data.rows.find(candidate => candidate.id === node.dataset.id);
        if (!row) {
            return;
        }
        event.preventDefault();
        select(row.id, false);
        openMenu(row, event.clientX, event.clientY);
    });

    document.addEventListener('click', event => {
        if (!el.menu.hidden && !el.menu.contains(/** @type {Node} */ (event.target))) {
            closeMenu();
        }
    });
    document.addEventListener('keydown', event => {
        if (event.key === 'Escape' && !el.menu.hidden) {
            closeMenu();
            el.list.focus();
        }
    });

    // -----------------------------------------------------------------------
    // Boot
    // -----------------------------------------------------------------------

    window.addEventListener('message', event => {
        const message = event.data;
        if (message.type !== 'rows') {
            return;
        }
        data = message;
        if (typeof data.rowSpacing === 'number') {
            document.documentElement.style.setProperty('--row-gap', `${data.rowSpacing}px`);
        }
        if (typeof data.borderWidth === 'number') {
            document.documentElement.style.setProperty('--border-width', `${data.borderWidth}px`);
        }
        // Follow the active tab unless the user has selected something else that is
        // still open.
        const active = data.rows.find(row => row.isActive);
        if (!data.rows.some(row => row.id === selectedId) || (active && message.followActive)) {
            selectedId = active ? active.id : undefined;
            saveState();
        }
        render();
        if (selectedId) {
            select(selectedId, true);
        }
    });

    el.list.tabIndex = 0;
    vscode.postMessage({ type: 'ready' });
})();