/**
 * RustDesk Standalone Web Client - Input Handler
 * 
 * Captures mouse and keyboard events from the remote desktop canvas
 * and converts them to RustDesk protocol messages.
 */

const RDInput = (() => {
    let _canvas = null;
    let _enabled = false;
    let _displayWidth = 0;
    let _displayHeight = 0;
    let _scaleX = 1;
    let _scaleY = 1;
    let _mouseButtons = 0;      // Current mouse button mask
    let _modifiers = [];         // Current modifier keys
    let _keyboardLocked = false;
    let _viewOnly = false;

    // Mouse button masks
    const MOUSE = {
        LEFT: 1,
        RIGHT: 2,
        MIDDLE: 4,
        BUTTON4: 8,
        BUTTON5: 16
    };

    // Modifier key mappings
    const MODIFIER_MAP = {
        'ControlLeft': 50,   // LeftControl
        'ControlRight': 54,  // RightControl
        'ShiftLeft': 51,     // LeftShift
        'ShiftRight': 55,    // RightShift
        'AltLeft': 52,       // LeftAlt
        'AltRight': 56,      // RightAlt
        'MetaLeft': 53,      // LeftMeta
        'MetaRight': 57,     // RightMeta
    };

    // Key name to ControlKey enum mapping
    const KEY_MAP = {
        'Alt': 1, 'Backspace': 2, 'CapsLock': 3, 'Control': 4, 'Delete': 5,
        'ArrowDown': 6, 'End': 7, 'Escape': 8,
        'F1': 9, 'F10': 10, 'F11': 11, 'F12': 12,
        'F2': 13, 'F3': 14, 'F4': 15, 'F5': 16, 'F6': 17,
        'F7': 18, 'F8': 19, 'F9': 20,
        'Home': 21, 'ArrowLeft': 22, 'Meta': 23,
        'PageDown': 24, 'PageUp': 25, 'Enter': 26, 'Return': 26,
        'ArrowRight': 27, 'Shift': 28, ' ': 29, 'Space': 29,
        'Tab': 30, 'ArrowUp': 31,
        'Insert': 49,
        'NumLock': 63, 'ScrollLock': 64,
        'PrintScreen': 66,
        'Numpad0': 32, 'Numpad1': 33, 'Numpad2': 34, 'Numpad3': 35,
        'Numpad4': 36, 'Numpad5': 37, 'Numpad6': 38, 'Numpad7': 39,
        'Numpad8': 40, 'Numpad9': 41,
        'NumpadAdd': 42, 'NumpadDecimal': 43, 'NumpadDelete': 44,
        'NumpadDivide': 45, 'NumpadEnter': 46,
        'NumpadMultiply': 47, 'NumpadSubtract': 48,
        'VolumeDown': 58, 'VolumeMute': 59, 'VolumeUp': 60,
        'ContextMenu': 61,
    };

    /**
     * Initialize input handler
     * @param {HTMLCanvasElement} canvas - The canvas to capture events from
     */
    function init(canvas) {
        _canvas = canvas;
        attachMouseEvents();
        attachKeyboardEvents();
        attachTouchEvents();
        attachWheelEvents();
        console.log('[RDInput] Initialized');
    }

    /**
     * Enable/disable input capture
     */
    function setEnabled(enabled) {
        _enabled = enabled;
        if (enabled) {
            _canvas.style.cursor = 'default';
        } else {
            _canvas.style.cursor = 'not-allowed';
        }
    }

    /**
     * Set view-only mode
     */
    function setViewOnly(viewOnly) {
        _viewOnly = viewOnly;
    }

    /**
     * Update display dimensions for coordinate mapping
     */
    function setDisplaySize(width, height) {
        _displayWidth = width;
        _displayHeight = height;
        updateScale();
    }

    /**
     * Calculate scale factors for coordinate mapping
     */
    function updateScale() {
        if (_canvas && _displayWidth > 0 && _displayHeight > 0) {
            _scaleX = _displayWidth / _canvas.clientWidth;
            _scaleY = _displayHeight / _canvas.clientHeight;
        } else {
            _scaleX = 1;
            _scaleY = 1;
        }
    }

    /**
     * Convert canvas coordinates to display coordinates
     */
    function canvasToDisplay(canvasX, canvasY) {
        return {
            x: Math.round(canvasX * _scaleX),
            y: Math.round(canvasY * _scaleY)
        };
    }

    /**
     * Attach mouse event listeners
     */
    function attachMouseEvents() {
        _canvas.addEventListener('mousedown', onMouseDown);
        _canvas.addEventListener('mouseup', onMouseUp);
        _canvas.addEventListener('mousemove', onMouseMove);
        _canvas.addEventListener('mouseenter', onMouseEnter);
        _canvas.addEventListener('mouseleave', onMouseLeave);
        _canvas.addEventListener('contextmenu', (e) => e.preventDefault());
    }

    /**
     * Attach keyboard event listeners
     */
    function attachKeyboardEvents() {
        document.addEventListener('keydown', onKeyDown);
        document.addEventListener('keyup', onKeyUp);
    }

    /**
     * Attach touch event listeners
     */
    function attachTouchEvents() {
        _canvas.addEventListener('touchstart', onTouchStart, { passive: false });
        _canvas.addEventListener('touchmove', onTouchMove, { passive: false });
        _canvas.addEventListener('touchend', onTouchEnd, { passive: false });
        _canvas.addEventListener('touchcancel', onTouchEnd, { passive: false });
    }

    /**
     * Attach wheel event listeners
     */
    function attachWheelEvents() {
        _canvas.addEventListener('wheel', onWheel, { passive: false });
    }

    /**
     * Handle mouse down
     */
    function onMouseDown(e) {
        if (!_enabled || _viewOnly) return;
        e.preventDefault();

        updateModifiers(e);

        let buttonMask = 0;
        switch (e.button) {
            case 0: buttonMask = MOUSE.LEFT; break;
            case 1: buttonMask = MOUSE.MIDDLE; break;
            case 2: buttonMask = MOUSE.RIGHT; break;
            case 3: buttonMask = MOUSE.BUTTON4; break;
            case 4: buttonMask = MOUSE.BUTTON5; break;
        }

        _mouseButtons |= buttonMask;

        const pos = canvasToDisplay(e.offsetX, e.offsetY);
        RDConnection.sendMouseEvent(_mouseButtons | getModifierMask(), pos.x, pos.y, getModifierList());

        // Focus for keyboard events
        _canvas.focus();
    }

    /**
     * Handle mouse up
     */
    function onMouseUp(e) {
        if (!_enabled || _viewOnly) return;
        e.preventDefault();

        updateModifiers(e);

        let buttonMask = 0;
        switch (e.button) {
            case 0: buttonMask = MOUSE.LEFT; break;
            case 1: buttonMask = MOUSE.MIDDLE; break;
            case 2: buttonMask = MOUSE.RIGHT; break;
            case 3: buttonMask = MOUSE.BUTTON4; break;
            case 4: buttonMask = MOUSE.BUTTON5; break;
        }

        _mouseButtons &= ~buttonMask;

        const pos = canvasToDisplay(e.offsetX, e.offsetY);
        RDConnection.sendMouseEvent(_mouseButtons | getModifierMask(), pos.x, pos.y, getModifierList());
    }

    /**
     * Handle mouse move
     */
    function onMouseMove(e) {
        if (!_enabled || _viewOnly) return;

        const pos = canvasToDisplay(e.offsetX, e.offsetY);
        RDConnection.sendMouseEvent(_mouseButtons | getModifierMask(), pos.x, pos.y, getModifierList());
    }

    /**
     * Handle mouse enter
     */
    function onMouseEnter(e) {
        // Notify peer that mouse entered the canvas
    }

    /**
     * Handle mouse leave
     */
    function onMouseLeave(e) {
        if (!_enabled || _viewOnly) return;

        // Send a release event when mouse leaves
        RDConnection.sendMouseEvent(0, -1, -1, []);
        _mouseButtons = 0;
    }

    /**
     * Handle mouse wheel
     */
    function onWheel(e) {
        if (!_enabled || _viewOnly) return;
        e.preventDefault();

        const buttonMask = e.deltaY > 0 ? MOUSE.BUTTON5 : MOUSE.BUTTON4;
        const pos = canvasToDisplay(e.offsetX, e.offsetY);

        // Press
        RDConnection.sendMouseEvent(buttonMask | getModifierMask(), pos.x, pos.y, getModifierList());
        // Release
        setTimeout(() => {
            RDConnection.sendMouseEvent(getModifierMask(), pos.x, pos.y, getModifierList());
        }, 20);
    }

    /**
     * Handle touch start
     */
    function onTouchStart(e) {
        if (!_enabled || _viewOnly) return;
        e.preventDefault();

        if (e.touches.length === 1) {
            const touch = e.touches[0];
            const rect = _canvas.getBoundingClientRect();
            const x = touch.clientX - rect.left;
            const y = touch.clientY - rect.top;
            const pos = canvasToDisplay(x, y);

            RDConnection.sendMouseEvent(MOUSE.LEFT | getModifierMask(), pos.x, pos.y, getModifierList());
            _mouseButtons = MOUSE.LEFT;
        }
    }

    /**
     * Handle touch move
     */
    function onTouchMove(e) {
        if (!_enabled || _viewOnly) return;
        e.preventDefault();

        if (e.touches.length === 1) {
            const touch = e.touches[0];
            const rect = _canvas.getBoundingClientRect();
            const x = touch.clientX - rect.left;
            const y = touch.clientY - rect.top;
            const pos = canvasToDisplay(x, y);

            RDConnection.sendMouseEvent(MOUSE.LEFT | getModifierMask(), pos.x, pos.y, getModifierList());
        }
    }

    /**
     * Handle touch end
     */
    function onTouchEnd(e) {
        if (!_enabled || _viewOnly) return;
        e.preventDefault();

        RDConnection.sendMouseEvent(getModifierMask(), -1, -1, []);
        _mouseButtons = 0;
    }

    /**
     * Handle key down
     */
    function onKeyDown(e) {
        if (!_enabled || _viewOnly) return;

        // Don't capture if we're typing in an input field
        if (e.target.tagName === 'INPUT' || e.target.tagName === 'TEXTAREA') return;

        e.preventDefault();
        e.stopPropagation();

        updateModifiers(e);

        const controlKey = KEY_MAP[e.key] || KEY_MAP[e.code];
        if (controlKey) {
            // Special key
            RDConnection.sendKeyEvent(controlKey, true, false, getModifierList());
        } else {
            // Regular character
            const charCode = e.key.charCodeAt(0);
            if (charCode > 0 && charCode < 65536) {
                RDConnection.sendCharEvent(charCode, true, false, getModifierList());
            }
        }
    }

    /**
     * Handle key up
     */
    function onKeyUp(e) {
        if (!_enabled || _viewOnly) return;

        if (e.target.tagName === 'INPUT' || e.target.tagName === 'TEXTAREA') return;

        e.preventDefault();
        e.stopPropagation();

        updateModifiers(e);

        const controlKey = KEY_MAP[e.key] || KEY_MAP[e.code];
        if (controlKey) {
            RDConnection.sendKeyEvent(controlKey, false, false, getModifierList());
        } else {
            const charCode = e.key.charCodeAt(0);
            if (charCode > 0 && charCode < 65536) {
                RDConnection.sendCharEvent(charCode, false, false, getModifierList());
            }
        }
    }

    /**
     * Update current modifier state
     */
    function updateModifiers(e) {
        _modifiers = [];
        if (e.ctrlKey || e.metaKey) _modifiers.push(4);  // Control
        if (e.shiftKey) _modifiers.push(28);               // Shift
        if (e.altKey) _modifiers.push(1);                   // Alt
    }

    /**
     * Get current modifier key list
     */
    function getModifierList() {
        return [..._modifiers];
    }

    /**
     * Get modifier bitmask for mouse events
     */
    function getModifierMask() {
        let mask = 0;
        if (_modifiers.includes(4)) mask |= 0x10;  // Ctrl
        if (_modifiers.includes(28)) mask |= 0x20; // Shift
        if (_modifiers.includes(1)) mask |= 0x40;  // Alt
        if (_modifiers.includes(23)) mask |= 0x80; // Meta
        return mask;
    }

    /**
     * Type a string of text (for paste/keyboard input)
     */
    function typeString(text) {
        if (!_enabled || _viewOnly) return;

        for (const char of text) {
            const charCode = char.charCodeAt(0);
            RDConnection.sendCharEvent(charCode, true, true, getModifierList());
        }
    }

    return {
        init,
        setEnabled,
        setViewOnly,
        setDisplaySize,
        typeString,
        MOUSE,
        get enabled() { return _enabled; }
    };
})();