/**
 * @license
 * Copyright 2025 Google LLC
 * SPDX-License-Identifier: Apache-2.0
 */
import { useCallback, useReducer, useEffect } from 'react';
import { useVimMode } from '../contexts/VimModeContext.js';
// Constants
const DIGIT_MULTIPLIER = 10;
const DEFAULT_COUNT = 1;
const DIGIT_1_TO_9 = /^[1-9]$/;
// Command types
const CMD_TYPES = {
    DELETE_WORD_FORWARD: 'dw',
    DELETE_WORD_BACKWARD: 'db',
    DELETE_WORD_END: 'de',
    CHANGE_WORD_FORWARD: 'cw',
    CHANGE_WORD_BACKWARD: 'cb',
    CHANGE_WORD_END: 'ce',
    DELETE_CHAR: 'x',
    DELETE_LINE: 'dd',
    CHANGE_LINE: 'cc',
    DELETE_TO_EOL: 'D',
    CHANGE_TO_EOL: 'C',
    CHANGE_MOVEMENT: {
        LEFT: 'ch',
        DOWN: 'cj',
        UP: 'ck',
        RIGHT: 'cl',
    },
};
// Helper function to clear pending state
const createClearPendingState = () => ({
    count: 0,
    pendingOperator: null,
});
const initialVimState = {
    mode: 'NORMAL',
    count: 0,
    pendingOperator: null,
    lastCommand: null,
};
// Reducer function
const vimReducer = (state, action) => {
    switch (action.type) {
        case 'SET_MODE':
            return { ...state, mode: action.mode };
        case 'SET_COUNT':
            return { ...state, count: action.count };
        case 'INCREMENT_COUNT':
            return { ...state, count: state.count * DIGIT_MULTIPLIER + action.digit };
        case 'CLEAR_COUNT':
            return { ...state, count: 0 };
        case 'SET_PENDING_OPERATOR':
            return { ...state, pendingOperator: action.operator };
        case 'SET_LAST_COMMAND':
            return { ...state, lastCommand: action.command };
        case 'CLEAR_PENDING_STATES':
            return {
                ...state,
                ...createClearPendingState(),
            };
        case 'ESCAPE_TO_NORMAL':
            // Handle escape - clear all pending states (mode is updated via context)
            return {
                ...state,
                ...createClearPendingState(),
            };
        default:
            return state;
    }
};
/**
 * React hook that provides vim-style editing functionality for text input.
 *
 * Features:
 * - Modal editing (INSERT/NORMAL modes)
 * - Navigation: h,j,k,l,w,b,e,0,$,^,gg,G with count prefixes
 * - Editing: x,a,i,o,O,A,I,d,c,D,C with count prefixes
 * - Complex operations: dd,cc,dw,cw,db,cb,de,ce
 * - Command repetition (.)
 * - Settings persistence
 *
 * @param buffer - TextBuffer instance for text manipulation
 * @param onSubmit - Optional callback for command submission
 * @returns Object with vim state and input handler
 */
export function useVim(buffer, onSubmit) {
    const { vimEnabled, vimMode, setVimMode } = useVimMode();
    const [state, dispatch] = useReducer(vimReducer, initialVimState);
    // Sync vim mode from context to local state
    useEffect(() => {
        dispatch({ type: 'SET_MODE', mode: vimMode });
    }, [vimMode]);
    // Helper to update mode in both reducer and context
    const updateMode = useCallback((mode) => {
        setVimMode(mode);
        dispatch({ type: 'SET_MODE', mode });
    }, [setVimMode]);
    // Helper functions using the reducer state
    const getCurrentCount = useCallback(() => state.count || DEFAULT_COUNT, [state.count]);
    /** Executes common commands to eliminate duplication in dot (.) repeat command */
    const executeCommand = useCallback((cmdType, count) => {
        switch (cmdType) {
            case CMD_TYPES.DELETE_WORD_FORWARD: {
                buffer.vimDeleteWordForward(count);
                break;
            }
            case CMD_TYPES.DELETE_WORD_BACKWARD: {
                buffer.vimDeleteWordBackward(count);
                break;
            }
            case CMD_TYPES.DELETE_WORD_END: {
                buffer.vimDeleteWordEnd(count);
                break;
            }
            case CMD_TYPES.CHANGE_WORD_FORWARD: {
                buffer.vimChangeWordForward(count);
                updateMode('INSERT');
                break;
            }
            case CMD_TYPES.CHANGE_WORD_BACKWARD: {
                buffer.vimChangeWordBackward(count);
                updateMode('INSERT');
                break;
            }
            case CMD_TYPES.CHANGE_WORD_END: {
                buffer.vimChangeWordEnd(count);
                updateMode('INSERT');
                break;
            }
            case CMD_TYPES.DELETE_CHAR: {
                buffer.vimDeleteChar(count);
                break;
            }
            case CMD_TYPES.DELETE_LINE: {
                buffer.vimDeleteLine(count);
                break;
            }
            case CMD_TYPES.CHANGE_LINE: {
                buffer.vimChangeLine(count);
                updateMode('INSERT');
                break;
            }
            case CMD_TYPES.CHANGE_MOVEMENT.LEFT:
            case CMD_TYPES.CHANGE_MOVEMENT.DOWN:
            case CMD_TYPES.CHANGE_MOVEMENT.UP:
            case CMD_TYPES.CHANGE_MOVEMENT.RIGHT: {
                const movementMap = {
                    [CMD_TYPES.CHANGE_MOVEMENT.LEFT]: 'h',
                    [CMD_TYPES.CHANGE_MOVEMENT.DOWN]: 'j',
                    [CMD_TYPES.CHANGE_MOVEMENT.UP]: 'k',
                    [CMD_TYPES.CHANGE_MOVEMENT.RIGHT]: 'l',
                };
                const movementType = movementMap[cmdType];
                if (movementType) {
                    buffer.vimChangeMovement(movementType, count);
                    updateMode('INSERT');
                }
                break;
            }
            case CMD_TYPES.DELETE_TO_EOL: {
                buffer.vimDeleteToEndOfLine();
                break;
            }
            case CMD_TYPES.CHANGE_TO_EOL: {
                buffer.vimChangeToEndOfLine();
                updateMode('INSERT');
                break;
            }
            default:
                return false;
        }
        return true;
    }, [buffer, updateMode]);
    /**
     * Handles key input in INSERT mode
     * @param normalizedKey - The normalized key input
     * @returns boolean indicating if the key was handled
     */
    const handleInsertModeInput = useCallback((normalizedKey) => {
        // Handle escape key immediately - switch to NORMAL mode on any escape
        if (normalizedKey.name === 'escape') {
            // Vim behavior: move cursor left when exiting insert mode (unless at beginning of line)
            buffer.vimEscapeInsertMode();
            dispatch({ type: 'ESCAPE_TO_NORMAL' });
            updateMode('NORMAL');
            return true;
        }
        // In INSERT mode, let InputPrompt handle completion keys and special commands
        if (normalizedKey.name === 'tab' ||
            (normalizedKey.name === 'return' && !normalizedKey.ctrl) ||
            normalizedKey.name === 'up' ||
            normalizedKey.name === 'down' ||
            (normalizedKey.ctrl && normalizedKey.name === 'r')) {
            return false; // Let InputPrompt handle completion
        }
        // Let InputPrompt handle Ctrl+V for clipboard image pasting
        if (normalizedKey.ctrl && normalizedKey.name === 'v') {
            return false; // Let InputPrompt handle clipboard functionality
        }
        // Let InputPrompt handle shell commands
        if (normalizedKey.sequence === '!' && buffer.text.length === 0) {
            return false;
        }
        // Special handling for Enter key to allow command submission (lower priority than completion)
        if (normalizedKey.name === 'return' &&
            !normalizedKey.ctrl &&
            !normalizedKey.meta) {
            if (buffer.text.trim() && onSubmit) {
                // Handle command submission directly
                const submittedValue = buffer.text;
                buffer.setText('');
                onSubmit(submittedValue);
                return true;
            }
            return true; // Handled by vim (even if no onSubmit callback)
        }
        // useKeypress already provides the correct format for TextBuffer
        buffer.handleInput(normalizedKey);
        return true; // Handled by vim
    }, [buffer, dispatch, updateMode, onSubmit]);
    /**
     * Normalizes key input to ensure all required properties are present
     * @param key - Raw key input
     * @returns Normalized key with all properties
     */
    const normalizeKey = useCallback((key) => ({
        name: key.name || '',
        sequence: key.sequence || '',
        ctrl: key.ctrl || false,
        meta: key.meta || false,
        shift: key.shift || false,
        paste: key.paste || false,
    }), []);
    /**
     * Handles change movement commands (ch, cj, ck, cl)
     * @param movement - The movement direction
     * @returns boolean indicating if command was handled
     */
    const handleChangeMovement = useCallback((movement) => {
        const count = getCurrentCount();
        dispatch({ type: 'CLEAR_COUNT' });
        buffer.vimChangeMovement(movement, count);
        updateMode('INSERT');
        const cmdTypeMap = {
            h: CMD_TYPES.CHANGE_MOVEMENT.LEFT,
            j: CMD_TYPES.CHANGE_MOVEMENT.DOWN,
            k: CMD_TYPES.CHANGE_MOVEMENT.UP,
            l: CMD_TYPES.CHANGE_MOVEMENT.RIGHT,
        };
        dispatch({
            type: 'SET_LAST_COMMAND',
            command: { type: cmdTypeMap[movement], count },
        });
        dispatch({ type: 'SET_PENDING_OPERATOR', operator: null });
        return true;
    }, [getCurrentCount, dispatch, buffer, updateMode]);
    /**
     * Handles operator-motion commands (dw/cw, db/cb, de/ce)
     * @param operator - The operator type ('d' for delete, 'c' for change)
     * @param motion - The motion type ('w', 'b', 'e')
     * @returns boolean indicating if command was handled
     */
    const handleOperatorMotion = useCallback((operator, motion) => {
        const count = getCurrentCount();
        const commandMap = {
            d: {
                w: CMD_TYPES.DELETE_WORD_FORWARD,
                b: CMD_TYPES.DELETE_WORD_BACKWARD,
                e: CMD_TYPES.DELETE_WORD_END,
            },
            c: {
                w: CMD_TYPES.CHANGE_WORD_FORWARD,
                b: CMD_TYPES.CHANGE_WORD_BACKWARD,
                e: CMD_TYPES.CHANGE_WORD_END,
            },
        };
        const cmdType = commandMap[operator][motion];
        executeCommand(cmdType, count);
        dispatch({
            type: 'SET_LAST_COMMAND',
            command: { type: cmdType, count },
        });
        dispatch({ type: 'CLEAR_COUNT' });
        dispatch({ type: 'SET_PENDING_OPERATOR', operator: null });
        return true;
    }, [getCurrentCount, executeCommand, dispatch]);
    const handleInput = useCallback((key) => {
        if (!vimEnabled) {
            return false; // Let InputPrompt handle it
        }
        let normalizedKey;
        try {
            normalizedKey = normalizeKey(key);
        }
        catch (error) {
            // Handle malformed key inputs gracefully
            console.warn('Malformed key input in vim mode:', key, error);
            return false;
        }
        // Handle INSERT mode
        if (state.mode === 'INSERT') {
            return handleInsertModeInput(normalizedKey);
        }
        // Handle NORMAL mode
        if (state.mode === 'NORMAL') {
            // If in NORMAL mode, allow escape to pass through to other handlers
            // if there's no pending operation.
            if (normalizedKey.name === 'escape') {
                if (state.pendingOperator) {
                    dispatch({ type: 'CLEAR_PENDING_STATES' });
                    return true; // Handled by vim
                }
                return false; // Pass through to other handlers
            }
            // Handle count input (numbers 1-9, and 0 if count > 0)
            if (DIGIT_1_TO_9.test(normalizedKey.sequence) ||
                (normalizedKey.sequence === '0' && state.count > 0)) {
                dispatch({
                    type: 'INCREMENT_COUNT',
                    digit: parseInt(normalizedKey.sequence, 10),
                });
                return true; // Handled by vim
            }
            const repeatCount = getCurrentCount();
            switch (normalizedKey.sequence) {
                case 'h': {
                    // Check if this is part of a change command (ch)
                    if (state.pendingOperator === 'c') {
                        return handleChangeMovement('h');
                    }
                    // Normal left movement
                    buffer.vimMoveLeft(repeatCount);
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case 'j': {
                    // Check if this is part of a change command (cj)
                    if (state.pendingOperator === 'c') {
                        return handleChangeMovement('j');
                    }
                    // Normal down movement
                    buffer.vimMoveDown(repeatCount);
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case 'k': {
                    // Check if this is part of a change command (ck)
                    if (state.pendingOperator === 'c') {
                        return handleChangeMovement('k');
                    }
                    // Normal up movement
                    buffer.vimMoveUp(repeatCount);
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case 'l': {
                    // Check if this is part of a change command (cl)
                    if (state.pendingOperator === 'c') {
                        return handleChangeMovement('l');
                    }
                    // Normal right movement
                    buffer.vimMoveRight(repeatCount);
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case 'w': {
                    // Check if this is part of a delete or change command (dw/cw)
                    if (state.pendingOperator === 'd') {
                        return handleOperatorMotion('d', 'w');
                    }
                    if (state.pendingOperator === 'c') {
                        return handleOperatorMotion('c', 'w');
                    }
                    // Normal word movement
                    buffer.vimMoveWordForward(repeatCount);
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case 'b': {
                    // Check if this is part of a delete or change command (db/cb)
                    if (state.pendingOperator === 'd') {
                        return handleOperatorMotion('d', 'b');
                    }
                    if (state.pendingOperator === 'c') {
                        return handleOperatorMotion('c', 'b');
                    }
                    // Normal backward word movement
                    buffer.vimMoveWordBackward(repeatCount);
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case 'e': {
                    // Check if this is part of a delete or change command (de/ce)
                    if (state.pendingOperator === 'd') {
                        return handleOperatorMotion('d', 'e');
                    }
                    if (state.pendingOperator === 'c') {
                        return handleOperatorMotion('c', 'e');
                    }
                    // Normal word end movement
                    buffer.vimMoveWordEnd(repeatCount);
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case 'x': {
                    // Delete character under cursor
                    buffer.vimDeleteChar(repeatCount);
                    dispatch({
                        type: 'SET_LAST_COMMAND',
                        command: { type: CMD_TYPES.DELETE_CHAR, count: repeatCount },
                    });
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case 'i': {
                    // Enter INSERT mode at current position
                    buffer.vimInsertAtCursor();
                    updateMode('INSERT');
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case 'a': {
                    // Enter INSERT mode after current position
                    buffer.vimAppendAtCursor();
                    updateMode('INSERT');
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case 'o': {
                    // Insert new line after current line and enter INSERT mode
                    buffer.vimOpenLineBelow();
                    updateMode('INSERT');
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case 'O': {
                    // Insert new line before current line and enter INSERT mode
                    buffer.vimOpenLineAbove();
                    updateMode('INSERT');
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case '0': {
                    // Move to start of line
                    buffer.vimMoveToLineStart();
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case '$': {
                    // Move to end of line
                    buffer.vimMoveToLineEnd();
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case '^': {
                    // Move to first non-whitespace character
                    buffer.vimMoveToFirstNonWhitespace();
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case 'g': {
                    if (state.pendingOperator === 'g') {
                        // Second 'g' - go to first line (gg command)
                        buffer.vimMoveToFirstLine();
                        dispatch({ type: 'SET_PENDING_OPERATOR', operator: null });
                    }
                    else {
                        // First 'g' - wait for second g
                        dispatch({ type: 'SET_PENDING_OPERATOR', operator: 'g' });
                    }
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case 'G': {
                    if (state.count > 0) {
                        // Go to specific line number (1-based) when a count was provided
                        buffer.vimMoveToLine(state.count);
                    }
                    else {
                        // Go to last line when no count was provided
                        buffer.vimMoveToLastLine();
                    }
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case 'I': {
                    // Enter INSERT mode at start of line (first non-whitespace)
                    buffer.vimInsertAtLineStart();
                    updateMode('INSERT');
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case 'A': {
                    // Enter INSERT mode at end of line
                    buffer.vimAppendAtLineEnd();
                    updateMode('INSERT');
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case 'd': {
                    if (state.pendingOperator === 'd') {
                        // Second 'd' - delete N lines (dd command)
                        const repeatCount = getCurrentCount();
                        executeCommand(CMD_TYPES.DELETE_LINE, repeatCount);
                        dispatch({
                            type: 'SET_LAST_COMMAND',
                            command: { type: CMD_TYPES.DELETE_LINE, count: repeatCount },
                        });
                        dispatch({ type: 'CLEAR_COUNT' });
                        dispatch({ type: 'SET_PENDING_OPERATOR', operator: null });
                    }
                    else {
                        // First 'd' - wait for movement command
                        dispatch({ type: 'SET_PENDING_OPERATOR', operator: 'd' });
                    }
                    return true;
                }
                case 'c': {
                    if (state.pendingOperator === 'c') {
                        // Second 'c' - change N entire lines (cc command)
                        const repeatCount = getCurrentCount();
                        executeCommand(CMD_TYPES.CHANGE_LINE, repeatCount);
                        dispatch({
                            type: 'SET_LAST_COMMAND',
                            command: { type: CMD_TYPES.CHANGE_LINE, count: repeatCount },
                        });
                        dispatch({ type: 'CLEAR_COUNT' });
                        dispatch({ type: 'SET_PENDING_OPERATOR', operator: null });
                    }
                    else {
                        // First 'c' - wait for movement command
                        dispatch({ type: 'SET_PENDING_OPERATOR', operator: 'c' });
                    }
                    return true;
                }
                case 'D': {
                    // Delete from cursor to end of line (equivalent to d$)
                    executeCommand(CMD_TYPES.DELETE_TO_EOL, 1);
                    dispatch({
                        type: 'SET_LAST_COMMAND',
                        command: { type: CMD_TYPES.DELETE_TO_EOL, count: 1 },
                    });
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case 'C': {
                    // Change from cursor to end of line (equivalent to c$)
                    executeCommand(CMD_TYPES.CHANGE_TO_EOL, 1);
                    dispatch({
                        type: 'SET_LAST_COMMAND',
                        command: { type: CMD_TYPES.CHANGE_TO_EOL, count: 1 },
                    });
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                case '.': {
                    // Repeat last command
                    if (state.lastCommand) {
                        const cmdData = state.lastCommand;
                        // All repeatable commands are now handled by executeCommand
                        executeCommand(cmdData.type, cmdData.count);
                    }
                    dispatch({ type: 'CLEAR_COUNT' });
                    return true;
                }
                default: {
                    // Check for arrow keys (they have different sequences but known names)
                    if (normalizedKey.name === 'left') {
                        // Left arrow - same as 'h'
                        if (state.pendingOperator === 'c') {
                            return handleChangeMovement('h');
                        }
                        // Normal left movement (same as 'h')
                        buffer.vimMoveLeft(repeatCount);
                        dispatch({ type: 'CLEAR_COUNT' });
                        return true;
                    }
                    if (normalizedKey.name === 'down') {
                        // Down arrow - same as 'j'
                        if (state.pendingOperator === 'c') {
                            return handleChangeMovement('j');
                        }
                        // Normal down movement (same as 'j')
                        buffer.vimMoveDown(repeatCount);
                        dispatch({ type: 'CLEAR_COUNT' });
                        return true;
                    }
                    if (normalizedKey.name === 'up') {
                        // Up arrow - same as 'k'
                        if (state.pendingOperator === 'c') {
                            return handleChangeMovement('k');
                        }
                        // Normal up movement (same as 'k')
                        buffer.vimMoveUp(repeatCount);
                        dispatch({ type: 'CLEAR_COUNT' });
                        return true;
                    }
                    if (normalizedKey.name === 'right') {
                        // Right arrow - same as 'l'
                        if (state.pendingOperator === 'c') {
                            return handleChangeMovement('l');
                        }
                        // Normal right movement (same as 'l')
                        buffer.vimMoveRight(repeatCount);
                        dispatch({ type: 'CLEAR_COUNT' });
                        return true;
                    }
                    // Unknown command, clear count and pending states
                    dispatch({ type: 'CLEAR_PENDING_STATES' });
                    return true; // Still handled by vim to prevent other handlers
                }
            }
        }
        return false; // Not handled by vim
    }, [
        vimEnabled,
        normalizeKey,
        handleInsertModeInput,
        state.mode,
        state.count,
        state.pendingOperator,
        state.lastCommand,
        dispatch,
        getCurrentCount,
        handleChangeMovement,
        handleOperatorMotion,
        buffer,
        executeCommand,
        updateMode,
    ]);
    return {
        mode: state.mode,
        vimModeEnabled: vimEnabled,
        handleInput, // Expose the input handler for InputPrompt to use
    };
}
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