// API Endpoint Config (相对路径, 同源部署无需跨域)
const BASE_URL = '/api';

// 数据截止时间缓存
let dataCutoffCache = {};

// ECharts Instances
let trendChart;
let tagChart;

// Initialize when DOM is loaded
document.addEventListener('DOMContentLoaded', () => {
    initCharts();
    setupNavigation();
    setupRepurchasePeriod();
    
    // Fetch cutoff dates + initial page data
    fetchDataCutoff();
    fetchData();
});

// Setup SPA Navigation
function setupNavigation() {
    const navItems = document.querySelectorAll('.nav-item');
    const sections = {
        '大盘总览': 'page-overview',
        '商品洞察': 'page-product',
        '会员画像': 'page-customer',
        '订货建议': 'page-advice',
        '运维管理': 'page-ops'
    };

    // 页面名 → 标题文本 映射
    const pageTitles = {
        '大盘总览': '经营数据大盘概览',
        '商品洞察': '商品洞察分析',
        '会员画像': '会员画像分析',
        '订货建议': '智能订货建议',
        '运维管理': '运维管理'
    };

    // 页面名 → 截止日期 key 映射
    const cutoffKeys = {
        '大盘总览': 'overview',
        '商品洞察': 'product',
        '会员画像': 'customer',
        '订货建议': 'advice'
    };

    navItems.forEach(item => {
        item.addEventListener('click', (e) => {
            e.preventDefault();
            navItems.forEach(nav => nav.classList.remove('active'));
            item.classList.add('active');
            
            const pageTitle = item.textContent.trim();
            document.getElementById('page-title').textContent = pageTitles[pageTitle] || pageTitle;
            
            // 更新数据截止日期
            const badge = document.getElementById('data-cutoff-badge');
            const cutoffKey = cutoffKeys[pageTitle];
            if (cutoffKey && dataCutoffCache[cutoffKey]) {
                badge.textContent = `计算数据截止至 ${dataCutoffCache[cutoffKey]}`;
                badge.style.display = '';
            } else if (pageTitle === '运维管理') {
                badge.style.display = 'none';
            } else {
                badge.textContent = '计算数据截止至 —';
                badge.style.display = '';
            }
            
            document.querySelectorAll('.page-section').forEach(sec => sec.style.display = 'none');
            const targetId = sections[pageTitle];
            if(targetId) {
                document.getElementById(targetId).style.display = 'block';
            }
            
            fetchDataForPage(pageTitle);
        });
    });
}

// Initialize ECharts with premium minimalist styling
function initCharts() {
    trendChart = echarts.init(document.getElementById('trendChart'), null, { renderer: 'svg' });
    tagChart = echarts.init(document.getElementById('tagChart'), null, { renderer: 'svg' });
    
    // Resize observer to keep chart responsive
    window.addEventListener('resize', () => {
        trendChart.resize();
        tagChart.resize();
    });
}

// Format currency
function formatCurrency(val) {
    if (val === undefined || val === null) return '¥0.00';
    return '¥' + parseFloat(val).toLocaleString('zh-CN', { minimumFractionDigits: 2, maximumFractionDigits: 2 });
}

// Format percentages
function formatPercent(val) {
    if (val === undefined || val === null) return '0%';
    return (parseFloat(val) * 100).toFixed(1) + '%';
}

// Fetch all data for current active page
async function fetchData() {
    const activeNav = document.querySelector('.nav-item.active');
    if (activeNav) {
        await fetchDataForPage(activeNav.textContent.trim());
    }
}

async function fetchDataForPage(pageName) {
    const btn = document.querySelector('.btn-refresh');
    btn.textContent = '加载中...';
    btn.classList.add('loading');
    
    try {
        if (pageName === '大盘总览') {
            await Promise.all([fetchOverview(), fetchTrend()]);
        } else if (pageName === '商品洞察') {
            await Promise.all([fetchRepurchase(), fetchBasket()]);
        } else if (pageName === '会员画像') {
            await Promise.all([fetchRfm(), fetchTags()]);
            // echarts requires explicit resize when un-hidden
            setTimeout(() => tagChart.resize(), 100);
        } else if (pageName === '订货建议') {
            await fetchAdvice();
        }
    } catch (error) {
        console.error("Failed to fetch data:", error);
    } finally {
        setTimeout(() => {
            btn.textContent = '刷新数据';
            btn.classList.remove('loading');
        }, 500);
    }
}

// ============== DATA CUTOFF ==============
async function fetchDataCutoff() {
    try {
        const response = await fetch(`${BASE_URL}/dashboard/data-cutoff`);
        if (!response.ok) return;
        dataCutoffCache = await response.json();
        // 更新当前页面的截止日期
        const badge = document.getElementById('data-cutoff-badge');
        if (dataCutoffCache.overview) {
            badge.textContent = `计算数据截止至 ${dataCutoffCache.overview}`;
        }
    } catch (e) { console.error('fetchDataCutoff error:', e); }
}

// ============== PAGE 1: OVERVIEW ==============

async function fetchOverview() {
    try {
        const response = await fetch(`${BASE_URL}/dashboard/overview`);
        if (!response.ok) return;
        const data = await response.json();
        animateValue(document.getElementById('revenue-val'), data.past_14d_revenue || 0, true);
        animateValue(document.getElementById('orders-val'), data.past_14d_orders || 0, false);
        animateValue(document.getElementById('atv-val'), data.past_14d_atv || 0, true);
        animateValue(document.getElementById('refund-val'), data.past_14d_refund || 0, true);
    } catch (e) { console.error(e); }
}

async function fetchTrend() {
    try {
        const response = await fetch(`${BASE_URL}/dashboard/trend`);
        if (!response.ok) return;
        const data = await response.json();
        
        const dates = data.map(item => item.stat_date);
        const revenues = data.map(item => parseFloat(item.revenue));
        const orders = data.map(item => parseInt(item.order_count));
        
        updateTrendChart(dates, revenues, orders);
    } catch (e) { console.error(e); }
}

// ============== PAGE 2: PRODUCT INSIGHTS ==============

// 当前选中的复购率统计周期
let repurchaseDays = 30;

async function fetchRepurchase(days) {
    if (days !== undefined) repurchaseDays = days;
    try {
        const response = await fetch(`${BASE_URL}/product/repurchase?days=${repurchaseDays}`);
        if (!response.ok) return;
        const data = await response.json();
        
        const tbody = document.querySelector('#repurchase-table tbody');
        tbody.innerHTML = '';
        if(data.length === 0) {
            tbody.innerHTML = '<tr><td colspan="5" class="text-center">暂无数据</td></tr>';
            return;
        }
        
        data.forEach(item => {
            const tr = document.createElement('tr');
            
            // Badge color logic
            let badgeClass = 'primary';
            if(item.matrix_tag === '核心引流爆款') badgeClass = 'success';
            if(item.matrix_tag === '体验差需淘汰') badgeClass = 'danger';
            if(item.matrix_tag === '小众潜力款') badgeClass = 'warning';
            
            tr.innerHTML = `
                <td><strong>${item.item_name || ('商品 '+item.item_id)}</strong></td>
                <td>${item.purchaser_count_30d} 人</td>
                <td>${item.repurchaser_count_30d} 人</td>
                <td>${formatPercent(item.repurchase_rate_30d)}</td>
                <td><span class="badge ${badgeClass}">${item.matrix_tag || '-'}</span></td>
            `;
            tbody.appendChild(tr);
        });
    } catch (e) {}
}

// 初始化复购率周期切换控件
function setupRepurchasePeriod() {
    const container = document.getElementById('repurchase-period');
    if (!container) return;
    container.addEventListener('click', (e) => {
        const btn = e.target.closest('.segment-btn');
        if (!btn) return;
        container.querySelectorAll('.segment-btn').forEach(b => b.classList.remove('active'));
        btn.classList.add('active');
        const days = parseInt(btn.dataset.days);
        fetchRepurchase(days);
    });
}

async function fetchBasket() {
    try {
        const response = await fetch(`${BASE_URL}/product/basket`);
        if (!response.ok) return;
        const data = await response.json();
        
        const tbody = document.querySelector('#basket-table tbody');
        tbody.innerHTML = '';
        if(data.length === 0) {
            tbody.innerHTML = '<tr><td colspan="4" class="text-center">暂无数据</td></tr>';
            return;
        }
        
        data.forEach(item => {
            const tr = document.createElement('tr');
            tr.innerHTML = `
                <td><strong>${item.item_name_a}</strong></td>
                <td>${item.item_name_b}</td>
                <td>${item.pair_order_count} 笔</td>
                <td><span class="badge primary">${formatPercent(item.confidence)}</span></td>
            `;
            tbody.appendChild(tr);
        });
    } catch (e) {}
}

// ============== PAGE 3: CUSTOMER INSIGHTS ==============
async function fetchRfm() {
    try {
        const response = await fetch(`${BASE_URL}/customer/rfm/distribution`);
        if (!response.ok) return;
        const data = await response.json();
        
        const container = document.getElementById('rfm-cards');
        container.innerHTML = '';
        
        // RFM 分组 → 计算逻辑说明
        const rfmTooltips = {
            '重要价值客户': 'R(最近消费)高 + F(消费频次)高 + M(消费金额)高, 核心忠实客户',
            '重要发展客户': 'R高 + F低 + M高, 消费金额大但频次不够, 需提升复购',
            '重要保持客户': 'R低 + F高 + M高, 消费频次和金额都高但最近未消费, 需唤醒',
            '重要挽留客户': 'R低 + F低 + M高, 曾经的高价值客户但已流失, 需重点挽回',
            '一般价值客户': 'R高 + F高 + M低, 活跃但消费金额偏低',
            '一般发展客户': 'R高 + F低 + M低, 新客户/偶发客户, 有发展潜力',
            '一般保持客户': 'R低 + F高 + M低, 活跃但金额低且近期未消费',
            '一般挽留客户': 'R低 + F低 + M低, 低价值流失客户',
        };

        data.forEach(item => {
            let trendClass = 'neutral';
            if(item.rfm_group.includes('重要')) trendClass = 'positive';
            if(item.rfm_group.includes('沉睡')) trendClass = 'negative';
            
            const tooltip = rfmTooltips[item.rfm_group] || 'RFM综合打分分群';
            const card = document.createElement('div');
            card.className = 'glass-card metric-card';
            card.innerHTML = `
                <h3>${item.rfm_group} <span class="info-icon" data-tooltip="${tooltip}">ⓘ</span></h3>
                <div class="value">${item.customer_count} <span style="font-size:1rem;font-weight:400;">人</span></div>
                <div class="trend ${trendClass}">营收贡献: ${formatCurrency(item.total_revenue_contribution)}</div>
            `;
            container.appendChild(card);
        });
    } catch (e) {}
}

async function fetchTags() {
    try {
        const response = await fetch(`${BASE_URL}/customer/tags`);
        if (!response.ok) return;
        const data = await response.json();
        
        // 标签名 → 定义说明 (鼠标悬浮时显示)
        const tagDefs = {
            '工作日常客': '90天内周一~周五消费 ≥ 3 次',
            '高客单囤货客': '有单笔订单实付 ≥ 200 元',
            '周末活跃客': '90天内周六日消费 ≥ 3 次',
            '新客户': '首单在近 30 天内',
            '沉睡客户': '最近一次消费距今 > 60 天',
            '高频复购客': '90天内消费 ≥ 10 次',
            '多品类客户': '90天内购买 ≥ 3 种不同商品',
            '大额客户': '历史累计消费 ≥ 1000 元',
        };

        const chartData = data.map(item => ({
            value: item.tagged_users_count,
            name: item.tag_name,
            definition: tagDefs[item.tag_name] || ''
        }));
        
        updateTagChart(chartData);
    } catch(e) {}
}

// ============== PAGE 4: ADVICE ==============
async function fetchAdvice() {
    try {
        const response = await fetch(`${BASE_URL}/product/advice`);
        if (!response.ok) return;
        const data = await response.json();
        
        const tbody = document.querySelector('#advice-table tbody');
        tbody.innerHTML = '';
        if(data.length === 0) {
            tbody.innerHTML = '<tr><td colspan="4" class="text-center">近14天数据不足，无法生成建议</td></tr>';
            return;
        }
        
        data.forEach(item => {
            const tr = document.createElement('tr');
            tr.innerHTML = `
                <td><strong>${item.item_name || item.item_id}</strong></td>
                <td>${item.sum_14d} 件</td>
                <td>${parseFloat(item.avg_daily_speed).toFixed(2)} 件/天</td>
                <td><span class="badge success">备货 ${item.advice_stock_qty} 件</span></td>
            `;
            tbody.appendChild(tr);
        });
    } catch (e) {}
}

// ============== CHART UPDATERS & UTILS ==============
function updateTrendChart(dates, revenues, orders) {
    const isDarkMode = window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches;
    const textColor = isDarkMode ? '#f5f5f7' : '#1d1d1f';
    const gridLineColor = isDarkMode ? 'rgba(255, 255, 255, 0.05)' : 'rgba(0, 0, 0, 0.04)';
    
    trendChart.setOption({
        tooltip: {
            trigger: 'axis',
            backgroundColor: isDarkMode ? 'rgba(28, 28, 30, 0.9)' : 'rgba(255, 255, 255, 0.9)',
            borderColor: isDarkMode ? 'rgba(255, 255, 255, 0.1)' : 'rgba(0, 0, 0, 0.1)',
            textStyle: { color: textColor, fontFamily: 'Inter' },
            backdropFilter: 'blur(20px)',
            borderRadius: 12, padding: 12
        },
        legend: { data: ['销售额', '订单数'], textStyle: { color: '#86868b', fontFamily: 'Inter' }, top: 0, right: 0 },
        grid: { left: '3%', right: '4%', bottom: '3%', top: '15%', containLabel: true },
        xAxis: { type: 'category', boundaryGap: false, data: dates, axisLabel: { color: '#86868b' }, axisLine: { show: false }, axisTick: { show: false } },
        yAxis: [
            { type: 'value', name: 'Revenue', splitLine: { lineStyle: { color: gridLineColor, type: 'dashed' } }, axisLabel: { color: '#86868b' } },
            { type: 'value', name: 'Orders', position: 'right', splitLine: { show: false }, axisLabel: { color: '#86868b' } }
        ],
        series: [
            { name: '销售额', type: 'line', smooth: 0.4, symbol: 'none', itemStyle: { color: '#0071e3' }, lineStyle: { width: 3, shadowColor: 'rgba(0, 113, 227, 0.3)', shadowBlur: 10 },
              areaStyle: { color: new echarts.graphic.LinearGradient(0, 0, 0, 1, [{ offset: 0, color: 'rgba(0, 113, 227, 0.2)' }, { offset: 1, color: 'rgba(0, 113, 227, 0)' }]) },
              data: revenues },
            { name: '订单数', type: 'line', yAxisIndex: 1, smooth: 0.4, symbol: 'none', itemStyle: { color: '#ff3b30' }, lineStyle: { width: 2, type: 'dashed' }, data: orders }
        ],
        animationDuration: 1500
    });
}

function updateTagChart(chartData) {
    const isDarkMode = window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches;
    const textColor = isDarkMode ? '#f5f5f7' : '#1d1d1f';
    
    tagChart.setOption({
        tooltip: {
            trigger: 'item',
            backgroundColor: isDarkMode ? 'rgba(28, 28, 30, 0.95)' : 'rgba(255, 255, 255, 0.95)',
            textStyle: { color: textColor, fontFamily: 'Inter', fontSize: 13 },
            borderColor: isDarkMode ? 'rgba(255,255,255,0.08)' : 'rgba(0,0,0,0.06)',
            borderRadius: 12, padding: [12, 16],
            formatter: function(params) {
                const def = params.data.definition;
                let html = `<strong style="font-size:14px">${params.name}</strong><br/>`;
                html += `人数: <strong>${params.value}</strong> 人 (${params.percent}%)`;
                if (def) {
                    html += `<br/><span style="color:#86868b;font-size:12px">定义: ${def}</span>`;
                }
                return html;
            }
        },
        legend: { top: 'bottom', textStyle: { color: '#86868b', fontFamily: 'Inter' } },
        series: [
            {
                name: '画像人数',
                type: 'pie',
                radius: ['40%', '70%'],
                avoidLabelOverlap: false,
                itemStyle: {
                    borderRadius: 10,
                    borderColor: isDarkMode ? '#1c1c1e' : '#fff',
                    borderWidth: 2
                },
                label: { show: false, position: 'center' },
                emphasis: {
                    label: { show: true, fontSize: '18', fontWeight: 'bold', color: textColor }
                },
                labelLine: { show: false },
                data: chartData,
                color: ['#0071e3', '#34c759', '#ff9500', '#ff3b30', '#5856d6', '#ff2d55', '#30b0c7', '#a2845e']
            }
        ]
    });
}

function animateValue(obj, end, isCurrency) {
    let startTimestamp = null;
    const duration = 1000;
    const target = parseFloat(end);
    
    const step = (timestamp) => {
        if (!startTimestamp) startTimestamp = timestamp;
        const progress = Math.min((timestamp - startTimestamp) / duration, 1);
        const ease = 1 - Math.pow(1 - progress, 4);
        const current = target * ease;
        obj.innerHTML = isCurrency ? formatCurrency(current) : Math.floor(current);
        if (progress < 1) window.requestAnimationFrame(step);
        else obj.innerHTML = isCurrency ? formatCurrency(target) : target;
    };
    window.requestAnimationFrame(step);
}

// ============== PAGE 5: OPS MANAGEMENT ==============
function appendLog(logEl, emoji, text, cssClass) {
    const entry = document.createElement('span');
    entry.className = `log-entry ${cssClass || ''}`;
    const time = new Date().toLocaleTimeString('zh-CN');
    entry.innerHTML = `<span class="log-time">${time}</span>${emoji} ${text}`;
    logEl.appendChild(entry);
    logEl.scrollTop = logEl.scrollHeight;
}

async function triggerOps(action, btnElement) {
    const logEl = document.getElementById('ops-log');
    const taskName = btnElement.querySelector('.ops-label').textContent;
    
    // Clear the initial placeholder text on first use
    if (logEl.querySelector('.log-placeholder')) {
        logEl.innerHTML = '';
    }
    
    // Disable button & show running state
    btnElement.disabled = true;
    btnElement.classList.add('ops-running');
    const origDesc = btnElement.querySelector('.ops-desc').textContent;
    btnElement.querySelector('.ops-desc').textContent = '执行中...';
    
    appendLog(logEl, '⏳', `${taskName} 开始执行...`, 'log-pending');
    
    try {
        // 构建 URL: 订单/退款同步支持可选的 from 日期参数
        let url = `${BASE_URL.replace('/api', '')}/api/ops/${action}`;
        if (action === 'sync-orders' || action === 'sync-refunds') {
            const fromDate = document.getElementById('ops-from-date')?.value;
            if (fromDate) {
                url += `?from=${fromDate}`;
                appendLog(logEl, '📅', `使用指定日期: ${fromDate}`, 'log-pending');
            }
        }
        const response = await fetch(url);
        const data = await response.json();
        
        if (data.status === 'success') {
            const detail = data.message || (data.count !== undefined ? `处理 ${data.count} 条` : '完成');
            appendLog(logEl, '✅', `${taskName} 成功 — ${detail}`, 'log-success');
            btnElement.classList.add('ops-done');
        } else {
            appendLog(logEl, '❌', `${taskName} 失败: ${data.message || '未知错误'}`, 'log-error');
            btnElement.classList.add('ops-error');
        }
    } catch (e) {
        appendLog(logEl, '❌', `${taskName} 网络异常: ${e.message}`, 'log-error');
        btnElement.classList.add('ops-error');
    } finally {
        btnElement.disabled = false;
        btnElement.classList.remove('ops-running');
        btnElement.querySelector('.ops-desc').textContent = origDesc;
        
        setTimeout(() => {
            btnElement.classList.remove('ops-done', 'ops-error');
        }, 3000);
    }
}