document.addEventListener('DOMContentLoaded', async () => {
    await loadStats();

    const biasForm = document.getElementById('biasForm');
    biasForm.addEventListener('submit', async (e) => {
        e.preventDefault();
        const data = {
            job: document.getElementById('job').value,
            years: document.getElementById('years').value,
            edu: document.getElementById('edu').value,
            skill: document.getElementById('skill').value
        };

        const response = await fetch('/api/predict', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify(data)
        });

        const result = await response.json();
        const resultDiv = document.getElementById('predictionResult');
        resultDiv.style.display = 'block';

        if (result.decision === 1) {
            resultDiv.innerHTML = `<span style="color: #10b981; font-weight:700">SUGGESTED HIRE</span><br><small>Confidence: ${(result.probability * 100).toFixed(1)}%</small>`;
            resultDiv.style.background = 'rgba(16, 185, 129, 0.1)';
        } else {
            resultDiv.innerHTML = `<span style="color: #ef4444; font-weight:700">REJECTION LIKELY</span><br><small>Confidence: ${((1 - result.probability) * 100).toFixed(1)}%</small>`;
            resultDiv.style.background = 'rgba(239, 68, 68, 0.1)';
        }
    });
});

async function loadStats() {
    try {
        const response = await fetch('/api/stats');
        const data = await response.json();

        // Update Header Stats
        document.getElementById('totalCandidates').innerText = data.overview.total_candidates.toLocaleString();
        document.getElementById('aiApprovalRate').innerText = ((data.overview.ai_hired / data.overview.total_candidates) * 100).toFixed(1) + '%';
        document.getElementById('humanApprovalRate').innerText = ((data.overview.human_hired / data.overview.total_candidates) * 100).toFixed(1) + '%';
        document.getElementById('agreementRate').innerText = data.overview.agreement_rate.toFixed(1) + '%';

        renderChart('genderChart', data.gender_bias.map(m => m.group), data.gender_bias.map(m => m.selection_rate), 'Selection Rate by Gender');
        renderTable('genderTableBody', data.gender_bias);

        renderChart('raceChart', data.race_bias.map(m => m.group), data.race_bias.map(m => m.selection_rate), 'Selection Rate by Race');
        renderTable('raceTableBody', data.race_bias);
        renderIntersectionalTable('intersectionalTableBody', data.intersectional);

        // Mitigation Button
        const mitigateBtn = document.getElementById('mitigateBtn');
        mitigateBtn.addEventListener('click', async () => {
            mitigateBtn.innerText = 'Analyzing & Optimizing...';
            mitigateBtn.disabled = true;

            const res = await fetch('/api/mitigate', { method: 'POST' });
            const result = await res.json();

            const statusDiv = document.getElementById('mitigationStatus');
            statusDiv.style.display = 'block';
            statusDiv.innerHTML = `
                <div style="color: var(--success); font-weight:600">${result.status}</div>
                <div style="color: var(--text-muted)">Strategy: ${result.strategy}</div>
                <div style="color: var(--primary)">Result: ${result.improvement}</div>
            `;

            mitigateBtn.innerText = 'Mitigation Applied';
        });

    } catch (error) {
        console.error('Error loading stats:', error);
    }
}

function renderChart(id, labels, data, label) {
    const ctx = document.getElementById(id).getContext('2d');
    new Chart(ctx, {
        type: 'bar',
        data: {
            labels: labels,
            datasets: [{
                label: label,
                data: data,
                backgroundColor: 'rgba(99, 102, 241, 0.6)',
                borderColor: '#6366f1',
                borderWidth: 2,
                borderRadius: 5
            }]
        },
        options: {
            responsive: true,
            maintainAspectRatio: false,
            scales: {
                y: { beginAtZero: true, max: 1, grid: { color: 'rgba(255,255,255,0.05)' } },
                x: { grid: { display: false } }
            },
            plugins: {
                legend: { display: false }
            }
        }
    });
}

function renderTable(bodyId, data) {
    const body = document.getElementById(bodyId);
    body.innerHTML = '';
    data.forEach(item => {
        const di = item.disparate_impact;
        let status = 'Good';
        let cls = 'impact-good';

        if (di < 0.8) {
            status = 'Alert';
            cls = 'impact-bad';
        } else if (di < 0.9) {
            status = 'Warning';
            cls = 'impact-warn';
        }

        const row = `
            <tr>
                <td>${item.group}</td>
                <td>${(item.selection_rate * 100).toFixed(1)}%</td>
                <td>${di.toFixed(2)}</td>
                <td><span class="impact-badge ${cls}">${status}</span></td>
            </tr>
        `;
        body.innerHTML += row;
    });
}

function renderIntersectionalTable(bodyId, data) {
    const body = document.getElementById(bodyId);
    body.innerHTML = '';
    data.sort((a, b) => b.rate - a.rate);
    data.forEach(item => {
        const row = `
            <tr>
                <td style="font-size: 0.8rem">${item.group}</td>
                <td>${(item.rate * 100).toFixed(1)}%</td>
            </tr>
        `;
        body.innerHTML += row;
    });
}