// ========== 写死的选项数据 ==========

const ALL_CAMPS = [];
for (let i = 13; i <= 26; i++) {
    ALL_CAMPS.push(`训练营${i}期`);
}

const ALL_CLASSES = [];
for (let i = 1; i <= 25; i++) {
    ALL_CLASSES.push(`${i}班`);
}

const ALLOWED_EXTENSIONS = ['jpg', 'jpeg', 'png', 'gif', 'webp'];
const MAX_FILE_SIZE_MB = 20;
const MAX_FILES_COUNT = 100;

// ========== 状态管理 ==========

let state = {
    selectedCamp: '',
    selectedClass: '',
    selectedFiles: [],       // { file, id, previewUrl }
    uploadResults: [],       // { file, id, status, filename, reason, previewUrl }
    isUploading: false,
};

// ========== DOM 元素 ==========

const $ = (sel) => document.querySelector(sel);
const campSelect = $('#camp-select');
const classSelect = $('#class-select');
const fileInput = $('#file-input');
const uploadSection = $('.upload-section');
const selectArea = $('#select-area');
const previewSection = $('#preview-section');
const previewGrid = $('#preview-grid');
const selectedCount = $('#selected-count');
const btnUpload = $('#btn-upload');
const btnClearAll = $('#btn-clear-all');
const progressSection = $('#progress-section');
const progressText = $('#progress-text');
const progressPercent = $('#progress-percent');
const progressFill = $('#progress-fill');
const fileProgressList = $('#file-progress-list');
const resultSection = $('#result-section');
const resultSummary = $('#result-summary');
const resultGrid = $('#result-grid');
const btnRetry = $('#btn-retry');
const btnNewUpload = $('#btn-new-upload');

// ========== 初始化 ==========

function init() {
    loadFolders();
    bindEvents();
}

// ========== 文件夹加载（前端写死选项） ==========

function loadFolders() {
    campSelect.innerHTML = '<option value="">-- 请选择训练营 --</option>';
    ALL_CAMPS.forEach(camp => {
        const opt = document.createElement('option');
        opt.value = camp;
        opt.textContent = camp;
        campSelect.appendChild(opt);
    });
}

function onCampChange() {
    const campName = campSelect.value;
    state.selectedCamp = campName;

    classSelect.innerHTML = '';
    classSelect.disabled = true;
    state.selectedClass = '';

    if (!campName) {
        classSelect.innerHTML = '<option value="">-- 请先选择训练营 --</option>';
        return;
    }

    classSelect.disabled = false;
    classSelect.innerHTML = '<option value="">-- 请选择班级 --</option>';
    ALL_CLASSES.forEach(cls => {
        const opt = document.createElement('option');
        opt.value = cls;
        opt.textContent = cls;
        classSelect.appendChild(opt);
    });
}

function onClassChange() {
    state.selectedClass = classSelect.value;
}

// ========== 文件选择 ==========

function onFileSelect(e) {
    const files = Array.from(e.target.files);
    if (!files.length) return;

    const remaining = MAX_FILES_COUNT - state.selectedFiles.length;
    if (remaining <= 0) {
        alert(`最多只能选择 ${MAX_FILES_COUNT} 张图片`);
        fileInput.value = '';
        return;
    }

    const filesToAdd = files.slice(0, remaining);
    let rejected = 0;

    filesToAdd.forEach(file => {
        if (file.size > MAX_FILE_SIZE_MB * 1024 * 1024) {
            rejected++;
            return;
        }

        const ext = file.name.split('.').pop().toLowerCase();
        if (!ALLOWED_EXTENSIONS.includes(ext)) {
            rejected++;
            return;
        }

        const id = Date.now() + '_' + Math.random().toString(36).substr(2, 6);
        const previewUrl = URL.createObjectURL(file);
        state.selectedFiles.push({ file, id, previewUrl });
    });

    if (rejected > 0) {
        alert(`已跳过 ${rejected} 个文件（格式不支持或超过 20MB）`);
    }

    fileInput.value = '';
    renderPreview();
}

function removeFile(id) {
    const idx = state.selectedFiles.findIndex(f => f.id === id);
    if (idx !== -1) {
        URL.revokeObjectURL(state.selectedFiles[idx].previewUrl);
        state.selectedFiles.splice(idx, 1);
    }
    renderPreview();
}

function clearAllFiles() {
    state.selectedFiles.forEach(f => URL.revokeObjectURL(f.previewUrl));
    state.selectedFiles = [];
    renderPreview();
}

function renderPreview() {
    const count = state.selectedFiles.length;

    if (count === 0) {
        previewSection.style.display = 'none';
        selectArea.style.display = 'block';
        return;
    }

    selectArea.style.display = 'none';
    previewSection.style.display = 'block';
    selectedCount.textContent = count;

    btnUpload.disabled = !state.selectedCamp || !state.selectedClass || state.isUploading;

    previewGrid.innerHTML = '';
    state.selectedFiles.forEach(item => {
        const div = document.createElement('div');
        div.className = 'preview-item';
        div.innerHTML = `
            <img src="${item.previewUrl}" alt="${item.file.name}">
            <button class="remove-btn" onclick="removeFile('${item.id}')">×</button>
            <div class="file-name">${item.file.name}</div>
        `;
        previewGrid.appendChild(div);
    });
}

// ========== 上传逻辑（真实API） ==========

function uploadFile(file, campName, className, onProgress) {
    return new Promise((resolve) => {
        const formData = new FormData();
        formData.append('folder', campName);
        formData.append('class', className);
        formData.append('files', file);

        const xhr = new XMLHttpRequest();
        xhr.open('POST', '/api/upload');

        xhr.upload.onprogress = (e) => {
            if (e.lengthComputable) {
                onProgress(Math.round((e.loaded / e.total) * 100));
            }
        };

        xhr.onload = () => {
            try {
                const data = JSON.parse(xhr.responseText);
                if (xhr.status === 200 && data.uploaded && data.uploaded.length > 0) {
                    resolve({ type: 'success', filename: data.uploaded[0].filename });
                } else if (data.failed && data.failed.length > 0) {
                    resolve({ type: 'failed', reason: data.failed[0].reason });
                } else {
                    resolve({ type: 'failed', reason: data.error || '上传失败' });
                }
            } catch (e) {
                resolve({ type: 'failed', reason: '服务器响应异常' });
            }
        };

        xhr.onerror = () => {
            resolve({ type: 'failed', reason: '网络错误' });
        };

        xhr.ontimeout = () => {
            resolve({ type: 'failed', reason: '请求超时' });
        };

        xhr.timeout = 120000; // 2分钟超时
        xhr.send(formData);
    });
}

async function startUpload() {
    if (!state.selectedCamp || !state.selectedClass) {
        alert('请先选择训练营和班级');
        return;
    }
    if (state.selectedFiles.length === 0) {
        alert('请先选择图片');
        return;
    }

    state.isUploading = true;
    btnUpload.disabled = true;
    btnUpload.textContent = '上传中...';
    btnUpload.classList.add('uploading');

    // 切换到进度视图
    previewSection.style.display = 'none';
    resultSection.style.display = 'none';
    progressSection.style.display = 'block';

    // 初始化进度列表
    fileProgressList.innerHTML = '';
    state.selectedFiles.forEach(item => {
        const div = document.createElement('div');
        div.className = 'file-progress-item';
        div.id = `progress-${item.id}`;
        div.innerHTML = `
            <span class="status-icon">⏳</span>
            <div class="file-info">
                <div class="name">${item.file.name}</div>
                <div class="detail">等待上传...</div>
            </div>
            <div class="mini-progress"><div class="mini-fill" style="width:0%"></div></div>
        `;
        fileProgressList.appendChild(div);
    });

    // 逐张上传
    let completed = 0;
    const total = state.selectedFiles.length;
    state.uploadResults = [];

    for (const item of state.selectedFiles) {
        const el = $(`#progress-${item.id}`);
        const icon = el.querySelector('.status-icon');
        const detail = el.querySelector('.detail');
        const miniFill = el.querySelector('.mini-fill');

        // 上传中
        icon.textContent = '📤';
        detail.textContent = '上传中...';

        // 调用真实API
        const result = await uploadFile(item.file, state.selectedCamp, state.selectedClass, (percent) => {
            miniFill.style.width = `${percent}%`;
        });

        if (result.type === 'success') {
            icon.textContent = '✅';
            detail.textContent = result.filename;
            el.classList.add('status-success');
            miniFill.style.width = '100%';
            miniFill.style.background = '#52c41a';
            state.uploadResults.push({
                file: item.file,
                id: item.id,
                previewUrl: item.previewUrl,
                status: 'success',
                filename: result.filename,
            });
        } else if (result.type === 'failed') {
            icon.textContent = '❌';
            detail.textContent = `上传失败：${result.reason}`;
            el.classList.add('status-failed');
            miniFill.style.width = '100%';
            miniFill.style.background = '#ff4d4f';
            state.uploadResults.push({
                file: item.file,
                id: item.id,
                previewUrl: item.previewUrl,
                status: 'failed',
                filename: item.file.name,
                reason: result.reason,
            });
        }

        completed++;
        const percent = Math.round((completed / total) * 100);
        progressText.textContent = `上传中... ${completed} / ${total}`;
        progressPercent.textContent = `${percent}%`;
        progressFill.style.width = `${percent}%`;
    }

    // 上传完成
    state.isUploading = false;
    btnUpload.textContent = '开始上传';
    btnUpload.classList.remove('uploading');

    setTimeout(() => {
        progressSection.style.display = 'none';
        uploadSection.style.display = 'none';
        showResults();
    }, 500);
}

// ========== 结果展示 ==========

function showResults() {
    resultSection.style.display = 'block';

    const successList = state.uploadResults.filter(r => r.status === 'success');
    const failedList = state.uploadResults.filter(r => r.status === 'failed');

    let summaryHtml = `共上传 <strong>${state.uploadResults.length}</strong> 张图片，`;
    summaryHtml += `<span class="success-count">成功 ${successList.length} 张</span>`;
    if (failedList.length > 0) {
        summaryHtml += `，<span class="fail-count">失败 ${failedList.length} 张</span>`;
    }
    resultSummary.innerHTML = summaryHtml;

    btnRetry.style.display = failedList.length > 0 ? 'inline-block' : 'none';

    resultGrid.innerHTML = '';
    state.uploadResults.forEach(item => {
        const div = document.createElement('div');
        div.className = `result-item ${item.status}`;
        div.innerHTML = `
            <img src="${item.previewUrl}" alt="${item.filename}">
            <div class="result-name">${item.status === 'success' ? item.filename : item.filename}</div>
            <span class="result-status">${item.status === 'success' ? '✅' : '❌'}</span>
        `;
        resultGrid.appendChild(div);
    });
}

function retryFailed() {
    const failedItems = state.uploadResults.filter(r => r.status === 'failed');
    state.selectedFiles = failedItems.map(item => ({
        file: item.file,
        id: item.id,
        previewUrl: item.previewUrl,
    }));
    state.uploadResults = [];

    resultSection.style.display = 'none';
    progressSection.style.display = 'none';
    uploadSection.style.display = 'block';
    renderPreview();
}

function newUpload() {
    state.selectedFiles.forEach(f => URL.revokeObjectURL(f.previewUrl));
    state.selectedFiles = [];
    state.uploadResults = [];
    state.isUploading = false;

    resultSection.style.display = 'none';
    progressSection.style.display = 'none';
    uploadSection.style.display = 'block';
    previewSection.style.display = 'none';
    selectArea.style.display = 'block';
    btnUpload.disabled = true;
    btnUpload.textContent = '开始上传';
}

// ========== 事件绑定 ==========

function bindEvents() {
    campSelect.addEventListener('change', onCampChange);
    classSelect.addEventListener('change', onClassChange);
    fileInput.addEventListener('change', onFileSelect);
    btnUpload.addEventListener('click', startUpload);
    btnClearAll.addEventListener('click', clearAllFiles);
    btnRetry.addEventListener('click', retryFailed);
    btnNewUpload.addEventListener('click', newUpload);

    campSelect.addEventListener('change', () => {
        if (state.selectedFiles.length > 0) renderPreview();
    });
    classSelect.addEventListener('change', () => {
        if (state.selectedFiles.length > 0) renderPreview();
    });
}

// ========== 启动 ==========

document.addEventListener('DOMContentLoaded', init);