// ==UserScript==
// @name         ChatGPT Enter 换行
// @namespace    https://viayoo.com/9u286k
// @version      1.0.2
// @description  ChatGPT 输入框按 Enter 换行，Ctrl/Cmd + Enter 发送
// @author       ChatGPT
// @license      MIT
// @match        https://chatgpt.com/*
// @match        https://chat.openai.com/*
// @run-at       document-start
// @grant        none
// ==/UserScript==

(() => {
    'use strict';

    // 输入框选择器
    const SELECTORS = [
        '.ProseMirror[contenteditable="true"]',
    ].join(',');

    // 获取输入框元素
    function getInput(target) {
        if (!(target instanceof Element)) return null;
        return target.closest(SELECTORS);
    }

    // 判断是否在中文输入法中（选词阶段不拦截 Enter）
    function isComposing(event) {
        return event.isComposing || event.keyCode === 229;
    }

    // textarea 换行：光标处插入 \n
    function insertTextareaNewline(el) {
        const start = el.selectionStart;
        const end = el.selectionEnd;
        const value = el.value;

        el.value = value.slice(0, start) + '\n' + value.slice(end);
        const position = start + 1;
        el.setSelectionRange(position, position);

        el.dispatchEvent(new InputEvent('input', {
            bubbles: true,
            inputType: 'insertLineBreak',
            data: '\n',
        }));
    }

    // contenteditable 换行：光标处插入 <br>
    function insertContentEditableNewline(el) {
        el.focus();

        const selection = window.getSelection();
        if (!selection || selection.rangeCount === 0) return;

        const range = selection.getRangeAt(0);
        if (!el.contains(range.commonAncestorContainer)) return;

        range.deleteContents();

        const br = document.createElement('br');
        range.insertNode(br);

        range.setStartAfter(br);
        range.collapse(true);

        selection.removeAllRanges();
        selection.addRange(range);

        el.dispatchEvent(new InputEvent('input', {
            bubbles: true,
            inputType: 'insertLineBreak',
            data: null,
        }));
    }

    // 根据输入框类型插入换行
    function insertNewline(el) {
        if (el instanceof HTMLTextAreaElement) {
            insertTextareaNewline(el);
            return;
        }
        if (el.isContentEditable) {
            insertContentEditableNewline(el);
        }
    }

    // 键盘事件：Enter 换行，Ctrl+Enter 发送
    document.addEventListener('keydown', (event) => {
        if (event.key !== 'Enter') return;
        if (isComposing(event)) return;

        const input = getInput(event.target);
        if (!input) return;

        if (event.ctrlKey || event.metaKey) return;
        if (event.altKey) return;

        event.preventDefault();
        event.stopPropagation();
        event.stopImmediatePropagation();

        insertNewline(input);
    }, true);

})();