class AdminBilling extends HTMLElement {
    constructor() {
        super();
        this.pricingConfig = [];
        this.stats = null;
        this.boundHandleClick = this.handleClick.bind(this);
        this.loading = true;
        this.error = null;
    }

    async connectedCallback() {
        this.addEventListener('click', this.boundHandleClick);
        await this.loadData();
        this.render();
        this.attachEventListeners();
    }

    disconnectedCallback() {
        this.removeEventListener('click', this.boundHandleClick);
    }

    async loadData() {
        this.loading = true;
        this.error = null;
        try {
            const [pricing, stats] = await Promise.all([
                this.fetchPricing(),
                this.fetchStats()
            ]);

            this.pricingConfig = pricing;
            this.stats = stats;
            this.loading = false;
        } catch (error) {
            console.error('Failed to load admin billing data:', error);
            this.error = error.message || 'Failed to load admin billing data';
            this.loading = false;
        }
    }

    async fetchPricing() {
        const response = await fetch('/api/admin/billing/pricing', {
            headers: {'Authorization': `Bearer ${localStorage.getItem('token')}`}
        });
        return await response.json();
    }

    async fetchStats() {
        const response = await fetch('/api/admin/billing/stats', {
            headers: {'Authorization': `Bearer ${localStorage.getItem('token')}`}
        });
        return await response.json();
    }

    formatCurrency(amount) {
        return new Intl.NumberFormat('en-US', {
            style: 'currency',
            currency: 'USD'
        }).format(amount);
    }

    render() {
        if (this.loading) {
            this.innerHTML = '<div class="admin-billing"><div class="loading">Loading admin billing data...</div></div>';
            return;
        }

        if (this.error) {
            this.innerHTML = `<div class="admin-billing"><div class="error-message">Error: ${this.error}</div></div>`;
            return;
        }

        this.innerHTML = `
            <div class="admin-billing">
                <h2>Billing Administration</h2>

                <div class="stats-cards">
                    <div class="stat-card">
                        <h3>Total Revenue</h3>
                        <div class="stat-value">${this.formatCurrency(this.stats?.total_revenue || 0)}</div>
                    </div>
                    <div class="stat-card">
                        <h3>Total Invoices</h3>
                        <div class="stat-value">${this.stats?.total_invoices || 0}</div>
                    </div>
                    <div class="stat-card">
                        <h3>Pending Invoices</h3>
                        <div class="stat-value">${this.stats?.pending_invoices || 0}</div>
                    </div>
                </div>

                <div class="pricing-config-section">
                    <h3>Pricing Configuration</h3>
                    <table class="pricing-table">
                        <thead>
                            <tr>
                                <th>Configuration</th>
                                <th>Current Value</th>
                                <th>Unit</th>
                                <th>Actions</th>
                            </tr>
                        </thead>
                        <tbody>
                            ${this.pricingConfig.map(config => `
                                <tr data-config-id="${config.id}">
                                    <td>${config.description || config.config_key}</td>
                                    <td class="config-value">${config.config_value}</td>
                                    <td>${config.unit || '-'}</td>
                                    <td>
                                        <button class="btn-edit" data-config-id="${config.id}">Edit</button>
                                    </td>
                                </tr>
                            `).join('')}
                        </tbody>
                    </table>
                </div>

                <div class="invoice-generation-section">
                    <h3>Generate Invoices</h3>
                    <div class="invoice-gen-form">
                        <label>
                            Year:
                            <input type="number" id="invoiceYear" value="${new Date().getFullYear()}" min="2020">
                        </label>
                        <label>
                            Month:
                            <input type="number" id="invoiceMonth" value="${new Date().getMonth() + 1}" min="1" max="12">
                        </label>
                        <button class="btn-primary" id="generateInvoices">Generate All Invoices</button>
                    </div>
                </div>
            </div>
        `;
    }

    handleClick(e) {
        const target = e.target;

        if (target.classList.contains('btn-edit')) {
            const configId = target.dataset.configId;
            this.editPricing(configId);
            return;
        }

        if (target.id === 'generateInvoices') {
            this.generateInvoices();
        }
    }

    attachEventListeners() {
    }

    async editPricing(configId) {
        const config = this.pricingConfig.find(c => c.id === parseInt(configId));
        if (!config) return;

        const newValue = prompt(`Enter new value for ${config.config_key}:`, config.config_value);
        if (newValue === null) return;

        try {
            const response = await fetch(`/api/admin/billing/pricing/${configId}`, {
                method: 'PUT',
                headers: {
                    'Content-Type': 'application/json',
                    'Authorization': `Bearer ${localStorage.getItem('token')}`
                },
                body: JSON.stringify({
                    config_key: config.config_key,
                    config_value: parseFloat(newValue)
                })
            });

            if (response.ok) {
                alert('Pricing updated successfully');
                await this.loadData();
                this.render();
                this.attachEventListeners();
            } else {
                alert('Failed to update pricing');
            }
        } catch (error) {
            console.error('Error updating pricing:', error);
            alert('Error updating pricing');
        }
    }

    async generateInvoices() {
        const year = parseInt(this.querySelector('#invoiceYear').value);
        const month = parseInt(this.querySelector('#invoiceMonth').value);

        if (!confirm(`Generate invoices for ${month}/${year}?`)) return;

        try {
            const response = await fetch(`/api/admin/billing/generate-invoices/${year}/${month}`, {
                method: 'POST',
                headers: {'Authorization': `Bearer ${localStorage.getItem('token')}`}
            });

            const result = await response.json();
            alert(`Generated ${result.generated} invoices, skipped ${result.skipped} users`);
        } catch (error) {
            console.error('Error generating invoices:', error);
            alert('Failed to generate invoices');
        }
    }
}

customElements.define('admin-billing', AdminBilling);

export default AdminBilling;