// Analytics Page Module

class AnalyticsPage {
    constructor() {
        this.filters = {
            dateRange: '7d',
            client: 'all',
            provider: 'all'
        };
        this.init();
    }

    async init() {
        // Load data
        await Promise.all([
            this.loadClients(),
            this.loadCharts(),
            this.loadUsageData()
        ]);
        
        // Setup event listeners
        this.setupEventListeners();
    }

    async loadClients() {
        try {
            const clients = await window.api.get('/clients');
            this.renderClientFilter(clients);
        } catch (error) {
            console.error('Error loading clients for filter:', error);
        }
    }

    renderClientFilter(clients) {
        const select = document.getElementById('client-filter');
        if (!select) return;
        
        // Clear existing options except "All Clients"
        while (select.options.length > 1) {
            select.remove(1);
        }
        
        // Add client options
        clients.forEach(client => {
            const option = document.createElement('option');
            option.value = client.id;
            option.textContent = client.name || client.id;
            select.appendChild(option);
        });
    }

    async loadCharts() {
        // Fetch each data source independently so one failure doesn't kill the others
        const [timeSeriesResult, breakdownResult] = await Promise.allSettled([
            window.api.get('/usage/time-series'),
            window.api.get('/analytics/breakdown')
        ]);

        // Time-series chart
        if (timeSeriesResult.status === 'fulfilled') {
            const series = timeSeriesResult.value.series || [];
            if (series.length > 0) {
                this.renderAnalyticsChart(series);
            } else {
                this.showEmptyChart('analytics-chart', 'No request data in the last 24 hours');
            }
        } else {
            console.error('Error loading time series:', timeSeriesResult.reason);
            this.showEmptyChart('analytics-chart', 'Failed to load request data');
        }

        // Breakdown charts (clients + models)
        if (breakdownResult.status === 'fulfilled') {
            const breakdown = breakdownResult.value;
            const clients = breakdown.clients || [];
            const models = breakdown.models || [];

            if (clients.length > 0) {
                this.renderClientsChart(clients);
            } else {
                this.showEmptyChart('clients-chart', 'No client data available');
            }

            if (models.length > 0) {
                this.renderModelsChart(models);
            } else {
                this.showEmptyChart('models-chart', 'No model data available');
            }
        } else {
            console.error('Error loading analytics breakdown:', breakdownResult.reason);
            this.showEmptyChart('clients-chart', 'Failed to load client data');
            this.showEmptyChart('models-chart', 'Failed to load model data');
        }
    }

    showEmptyChart(canvasId, message) {
        const canvas = document.getElementById(canvasId);
        if (!canvas) return;
        const container = canvas.closest('.chart-container');
        if (container) {
            canvas.style.display = 'none';
            let msg = container.querySelector('.empty-chart-msg');
            if (!msg) {
                msg = document.createElement('div');
                msg.className = 'empty-chart-msg';
                msg.style.cssText = 'display:flex;align-items:center;justify-content:center;height:200px;color:var(--fg4);font-size:0.9rem;';
                container.appendChild(msg);
            }
            msg.textContent = message;
        }
    }

    renderAnalyticsChart(series) {
        const data = {
            labels: series.map(s => s.time),
            datasets: [
                {
                    label: 'Requests',
                    data: series.map(s => s.requests),
                    color: '#fe8019', // orange
                    fill: true
                },
                {
                    label: 'Tokens',
                    data: series.map(s => s.tokens),
                    color: '#b8bb26', // green
                    fill: true,
                    hidden: true
                }
            ]
        };
        
        window.chartManager.createLineChart('analytics-chart', data);
    }

    renderClientsChart(clients) {
        const data = {
            labels: clients.map(c => c.label),
            datasets: [{
                label: 'Requests',
                data: clients.map(c => c.value),
                color: '#83a598' // blue
            }]
        };
        
        window.chartManager.createHorizontalBarChart('clients-chart', data);
    }

    renderModelsChart(models) {
        const data = {
            labels: models.map(m => m.label),
            data: models.map(m => m.value),
            colors: window.chartManager.defaultColors
        };
        
        window.chartManager.createDoughnutChart('models-chart', data);
    }

    async loadUsageData() {
        try {
            const usageData = await window.api.get('/usage/detailed');
            this.renderUsageTable(usageData);
        } catch (error) {
            console.error('Error loading usage data:', error);
        }
    }

    renderUsageTable(data) {
        const tableBody = document.querySelector('#usage-table tbody');
        if (!tableBody) return;
        
        if (data.length === 0) {
            tableBody.innerHTML = '<tr><td colspan="7" class="text-center">No historical data found</td></tr>';
            return;
        }

        tableBody.innerHTML = data.map(row => `
            <tr>
                <td>${row.date}</td>
                <td><span class="badge-client">${row.client}</span></td>
                <td>${row.provider}</td>
                <td><code class="code-sm">${row.model}</code></td>
                <td>${row.requests.toLocaleString()}</td>
                <td>${window.api.formatNumber(row.tokens)}</td>
                <td>${window.api.formatCurrency(row.cost)}</td>
            </tr>
        `).join('');
    }

    setupEventListeners() {
        const refreshBtn = document.getElementById('refresh-analytics');
        if (refreshBtn) {
            refreshBtn.onclick = () => this.refresh();
        }
        
        // Export button
        const exportBtn = document.getElementById('export-data');
        if (exportBtn) {
            exportBtn.onclick = () => this.exportData();
        }
    }

    async exportData() {
        // Simple CSV export
        const data = await window.api.get('/usage/detailed');
        if (!data || data.length === 0) return;

        const headers = Object.keys(data[0]).join(',');
        const rows = data.map(obj => Object.values(obj).join(',')).join('\n');
        const csv = `${headers}\n${rows}`;

        const blob = new Blob([csv], { type: 'text/csv' });
        const url = URL.createObjectURL(blob);
        const a = document.createElement('a');
        a.href = url;
        a.download = `llm-proxy-usage-${new Date().toISOString().split('T')[0]}.csv`;
        document.body.appendChild(a);
        a.click();
        document.body.removeChild(a);
    }

    refresh() {
        this.loadCharts();
        this.loadUsageData();
        window.authManager.showToast('Analytics data refreshed', 'success');
    }
}

window.initAnalytics = async () => {
    window.analyticsPage = new AnalyticsPage();
};