(() => {
    const API_BASE = '/api/gui/files';
    const params = new URLSearchParams(window.location.search);
    const path = params.get('path');

    const editorArea = document.getElementById('editorArea');
    const filePathEl = document.getElementById('filePath');
    const statusInfo = document.getElementById('statusInfo');
    const saveBtn = document.getElementById('btnSave');
    const downloadBtn = document.getElementById('btnDownload');
    const backBtn = document.getElementById('btnBack');
    const fontIncreaseBtn = document.getElementById('btnIncreaseFont');
    const fontDecreaseBtn = document.getElementById('btnDecreaseFont');

    let originalContent = '';
    let dirty = false;
    let fontSize = 14;

    if (!path) {
        editorArea.value = '缺少 path 参数，无法加载文件。';
        editorArea.disabled = true;
        saveBtn.disabled = true;
        downloadBtn.disabled = true;
        statusInfo.textContent = '缺少路径';
        return;
    }

    filePathEl.textContent = path;

    function setDirty(value) {
        dirty = value;
        statusInfo.textContent = dirty ? '有未保存的更改' : '已保存';
        saveBtn.disabled = !dirty;
    }

    async function request(url, options = {}) {
        const response = await fetch(url, options);
        const data = await response.json().catch(() => ({}));
        if (!response.ok || data.success === false) {
            const message = data.error || data.message || `请求失败 (${response.status})`;
            throw new Error(message);
        }
        return data;
    }

    async function loadFile() {
        statusInfo.textContent = '加载中...';
        try {
            const result = await request(`${API_BASE}/text?path=${encodeURIComponent(path)}`);
            originalContent = result.content || '';
            editorArea.value = originalContent;
            setDirty(false);
            statusInfo.textContent = `最后修改时间：${result.modified_at}`;
        } catch (err) {
            editorArea.value = `文件加载失败：${err.message}`;
            editorArea.disabled = true;
            saveBtn.disabled = true;
            statusInfo.textContent = '无法加载文件';
        }
    }

    async function saveFile() {
        statusInfo.textContent = '保存中...';
        try {
            await request(`${API_BASE}/text`, {
                method: 'POST',
                headers: { 'Content-Type': 'application/json' },
                body: JSON.stringify({ path, content: editorArea.value }),
            });
            originalContent = editorArea.value;
            setDirty(false);
            statusInfo.textContent = '已保存';
        } catch (err) {
            statusInfo.textContent = `保存失败：${err.message}`;
        }
    }

    editorArea.addEventListener('input', () => {
        if (editorArea.disabled) return;
        setDirty(editorArea.value !== originalContent);
    });

    saveBtn.addEventListener('click', () => {
        if (!dirty) return;
        saveFile();
    });

    downloadBtn.addEventListener('click', () => {
        window.open(`${API_BASE}/download?path=${encodeURIComponent(path)}`, '_blank');
    });

    const getParentDirectory = () => {
        const segments = path.split('/').filter(Boolean);
        if (segments.length <= 1) {
            return '';
        }
        segments.pop();
        return segments.join('/');
    };

    const navigateToManager = () => {
        const parentDir = getParentDirectory();
        const target = parentDir ? `/file-manager?path=${encodeURIComponent(parentDir)}` : '/file-manager';
        window.location.href = target;
    };

    backBtn.addEventListener('click', () => {
        if (dirty) {
            const confirmLeave = window.confirm('有未保存的更改，确认要离开吗？');
            if (!confirmLeave) return;
        }
        navigateToManager();
    });

    fontIncreaseBtn.addEventListener('click', () => {
        fontSize = Math.min(fontSize + 1, 28);
        editorArea.style.fontSize = `${fontSize}px`;
    });

    fontDecreaseBtn.addEventListener('click', () => {
        fontSize = Math.max(fontSize - 1, 10);
        editorArea.style.fontSize = `${fontSize}px`;
    });

    window.addEventListener('beforeunload', (event) => {
        if (!dirty) return;
        event.preventDefault();
        event.returnValue = '';
    });

    loadFile().catch((err) => {
        console.error(err);
        statusInfo.textContent = err.message;
    });
})();