// CACHE MANAGEMENT

const CACHE_KEY = 'flood_assessment_cache';
const MAX_CACHE_SIZE = 5;

// Get cached entries from localStorage
function getCachedEntries() {
    try {
        const cached = localStorage.getItem(CACHE_KEY);
        return cached ? JSON.parse(cached) : [];
    } catch (e) {
        console.error('Error reading cache:', e);
        return [];
    }
}

function saveToCacheFunction(latitude, longitude, height, basement) {
    try {
        let entries = getCachedEntries();

        const newEntry = {
            latitude: parseFloat(latitude).toFixed(6),
            longitude: parseFloat(longitude).toFixed(6),
            height: parseFloat(height).toFixed(2),
            basement: parseFloat(basement).toFixed(2),
            timestamp: Date.now()
        };

        // Check if entry already exists
        const exists = entries.some(entry =>
            entry.latitude === newEntry.latitude &&
            entry.longitude === newEntry.longitude &&
            entry.height === newEntry.height &&
            entry.basement === newEntry.basement
        );

        if (!exists) {
            entries.unshift(newEntry);

            if (entries.length > MAX_CACHE_SIZE) {
                entries = entries.slice(0, MAX_CACHE_SIZE);
            }

            localStorage.setItem(CACHE_KEY, JSON.stringify(entries));
            updateDatalistSuggestions();
        }
    } catch (e) {
        console.error('Error saving to cache:', e);
    }
}

// Update datalist suggestions from cache
function updateDatalistSuggestions() {
    const entries = getCachedEntries();

    updateDatalist('lat-suggestions', entries, 'latitude');
    updateDatalist('lon-suggestions', entries, 'longitude');
    updateDatalist('height-suggestions', entries, 'height');
    updateDatalist('basement-suggestions', entries, 'basement');
}

// Update a specific datalist
function updateDatalist(datalistId, entries, field) {
    const datalist = document.getElementById(datalistId);
    if (!datalist) return;

    datalist.innerHTML = '';

    entries.forEach((entry) => {
        const option = document.createElement('option');
        option.value = entry[field];

        if (field === 'latitude') {
            option.label = `${entry.latitude} | Lon: ${entry.longitude}, H: ${entry.height}m, B: ${entry.basement}m`;
        } else if (field === 'longitude') {
            option.label = `${entry.longitude} | Lat: ${entry.latitude}, H: ${entry.height}m, B: ${entry.basement}m`;
        } else if (field === 'height') {
            option.label = `${entry.height}m | At: ${entry.latitude}, ${entry.longitude}`;
        } else if (field === 'basement') {
            option.label = `${entry.basement}m | At: ${entry.latitude}, ${entry.longitude}`;
        }

        datalist.appendChild(option);
    });
}

// Setup autofill functionality
function setupAutoFill() {
    const forms = [
        { suffix: '', latId: 'latitude', lonId: 'longitude' },
        { suffix: '2', latId: 'latitude2', lonId: 'longitude2' },
        { suffix: '3', latId: 'latitude3', lonId: 'longitude3' }
    ];

    forms.forEach(({ suffix, latId, lonId }) => {
        const latInput = document.getElementById(latId);
        const lonInput = document.getElementById(lonId);

        if (!latInput || !lonInput) return;

        const tryAutoFill = () => {
            const latValue = parseNumber(latInput.value);
            const lonValue = parseNumber(lonInput.value);

            if (isNaN(latValue) || isNaN(lonValue)) return;

            const entries = getCachedEntries();
            const normalizedLat = latValue.toFixed(6);
            const normalizedLon = lonValue.toFixed(6);

            // Find entry matching BOTH lat and lon
            const match = entries.find(entry =>
                entry.latitude === normalizedLat &&
                entry.longitude === normalizedLon
            );

            if (match) {
                const heightInput = document.getElementById('height' + suffix);
                const basementInput = document.getElementById('basement' + suffix);

                if (heightInput && basementInput) {
                    heightInput.value = match.height;
                    basementInput.value = match.basement;

                    [latInput, lonInput, heightInput, basementInput].forEach(input => {
                        input.classList.add('height-pulse');
                        setTimeout(() => input.classList.remove('height-pulse'), 800);
                    });
                }
            }
        };

        latInput.addEventListener('change', () => {
            setTimeout(tryAutoFill, 100);
        });

        lonInput.addEventListener('change', () => {
            setTimeout(tryAutoFill, 100);
        });
    });
}

// UTILITY FUNCTIONS

// Parse numbers with comma or dot as decimal separator
function parseNumber(value) {
    if (typeof value === 'string') {
        value = value.replace(',', '.');
    }
    return parseFloat(value);
}

// Format quality flag for display
function formatFlag(flag) {
    const flagMessages = {
        'missing_elevation': 'Elevation data unavailable',
        'missing_tpi': 'Topographic position data incomplete',
        'missing_slope': 'Slope data incomplete',
        'water_distance_unknown': 'Water proximity uncertain',
        'far_from_water_search_limited': 'Far from major water bodies (search radius limited)',
        'steep_terrain_dem_error_high': 'Steep terrain increases measurement uncertainty',
        'coastal_surge_risk_not_modeled': 'Coastal surge dynamics not fully captured'
    };
    return flagMessages[flag] || flag.replace(/_/g, ' ');
}

// UI INTERACTIONS

// Switch between assessment tabs
function switchTab(tabName) {
    document.querySelectorAll('.assessment-card').forEach(card => {
        card.classList.remove('active');
    });
    document.querySelectorAll('.nav-link').forEach(link => {
        link.classList.remove('active');
    });

    document.getElementById(tabName + '-card').classList.add('active');
    event.target.classList.add('active');
}

// API COMMUNICATION

// Predict building height from coordinates
async function predictHeight(latId, lonId, heightId, errorId, button) {
    const latInput = document.getElementById(latId);
    const lonInput = document.getElementById(lonId);
    const heightInput = document.getElementById(heightId);
    const errorBox = document.getElementById(errorId);

    if (!latInput || !lonInput || !heightInput || !errorBox) {
        return;
    }

    errorBox.style.display = 'none';
    errorBox.textContent = '';

    const latitude = parseFloat(latInput.value);
    const longitude = parseFloat(lonInput.value);

    if (isNaN(latitude) || isNaN(longitude)) {
        errorBox.textContent = 'Please enter latitude and longitude first.';
        errorBox.style.display = 'block';
        return;
    }

    const originalText = button.textContent;
    button.disabled = true;
    button.textContent = 'Predicting...';

    try {
        const response = await fetch('/predict_height', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({
                latitude,
                longitude,
                height: 0,
                basement: 0
            })
        });

        const data = await response.json();
        if (!response.ok || data.status !== 'success' || data.predicted_height == null) {
            const message = data.detail || data.error || 'Height prediction failed.';
            throw new Error(message);
        }

        const h = Number(data.predicted_height);
        heightInput.value = h.toFixed(2);
        heightInput.classList.add('height-pulse');
        setTimeout(() => {
            heightInput.classList.remove('height-pulse');
        }, 800);
    } catch (err) {
        errorBox.textContent = err.message || 'Height prediction failed.';
        errorBox.style.display = 'block';
    } finally {
        button.disabled = false;
        button.textContent = originalText;
    }
}

// Get height from Global Building Atlas (GBA)
async function getHeightFromGBA(latId, lonId, heightId, errorId, button) {
    const lat = parseNumber(document.getElementById(latId).value);
    const lon = parseNumber(document.getElementById(lonId).value);

    const errorBox = document.getElementById(errorId);
    if (errorBox) errorBox.textContent = '';

    if (Number.isNaN(lat) || Number.isNaN(lon)) {
        if (errorBox) errorBox.textContent = 'Please enter valid latitude and longitude.';
        return;
    }

    const originalText = button.textContent;
    button.disabled = true;
    button.textContent = 'Fetching...';

    try {
        const resp = await fetch('/get_height_gba', {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ latitude: lat, longitude: lon, height: 0, basement: 0 })
        });

        const data = await resp.json();
        if (!resp.ok) {
            const msg = data?.detail || 'Failed to get GBA height';
            throw new Error(msg);
        }

        const h = data.predicted_height;
        if (h === null || h === undefined) {
            throw new Error('No height returned');
        }

        document.getElementById(heightId).value = Number(h).toFixed(2);
    } catch (e) {
        if (errorBox) {
            errorBox.textContent = String(e.message || e);
            errorBox.style.display = 'block';
        }
    } finally {
        button.disabled = false;
        button.textContent = originalText;
    }
}

// Assess location vulnerability
async function assessLocation(event, endpoint, resultsId) {
    event.preventDefault();

    const tabName = resultsId.split('-')[0];
    const suffix = endpoint === '/assess' ? '' : (endpoint === '/explain' ? '2' : '3');
    const latitude = parseFloat(document.getElementById('latitude' + suffix).value);
    const longitude = parseFloat(document.getElementById('longitude' + suffix).value);
    const height = parseFloat(document.getElementById('height' + suffix).value) || 0;
    const basement = parseFloat(document.getElementById('basement' + suffix).value) || 0;

    document.getElementById(tabName + '-loading').style.display = 'block';
    document.getElementById(resultsId).style.display = 'none';
    document.getElementById(tabName + '-error').style.display = 'none';

    try {
        const response = await fetch(endpoint, {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({ latitude, longitude, height, basement })
        });

        const data = await response.json();

        if (data.status === 'success') {
            // Save to cache on successful assessment
            saveToCacheFunction(latitude, longitude, height, basement);
            displayResults(data, resultsId, endpoint);
        } else {
            throw new Error(data.detail || 'Assessment failed');
        }
    } catch (error) {
        document.getElementById(tabName + '-error').textContent = error.message;
        document.getElementById(tabName + '-error').style.display = 'block';
    } finally {
        document.getElementById(tabName + '-loading').style.display = 'none';
    }
}

/**
 * Upload and process batch CSV file
 */
async function uploadBatch() {
    const fileInput = document.getElementById('csvFile');
    const file = fileInput.files[0];

    if (!file) {
        alert('Please select a CSV file');
        return;
    }

    document.getElementById('batch-loading').style.display = 'block';
    document.getElementById('batch-results').style.display = 'none';
    document.getElementById('batch-error').style.display = 'none';

    const formData = new FormData();
    formData.append('file', file);

    try {
        const mode = document.getElementById('batchMode').value;
        const heightSource = document.getElementById('heightSource').value;
        let endpoint = mode === 'multihazard' ? '/assess_batch_multihazard' : '/assess_batch';

        if (heightSource === 'gba') {
            const sep = endpoint.includes('?') ? '&' : '?';
            endpoint = endpoint + sep + 'use_gba_height=true';
        } else if (heightSource === 'predicted') {
            const sep = endpoint.includes('?') ? '&' : '?';
            endpoint = endpoint + sep + 'use_predicted_height=true';
        }

        const response = await fetch(endpoint, {
            method: 'POST',
            body: formData
        });

        if (response.ok) {
            const blob = await response.blob();
            const url = window.URL.createObjectURL(blob);
            const a = document.createElement('a');
            a.href = url;
            const filename = mode === 'multihazard'
                ? 'multihazard_results.csv'
                : 'vulnerability_results.csv';
            a.download = filename;
            document.body.appendChild(a);
            a.click();
            window.URL.revokeObjectURL(url);

            document.getElementById('batch-results').innerHTML = `
                <div class="results-header">
                    <h2>✓ Processing Complete</h2>
                    <p style="color: #94a3b8; margin-top: 1rem;">Results downloaded as ${filename}</p>
                </div>
            `;
            document.getElementById('batch-results').style.display = 'block';
        } else {
            throw new Error('Batch processing failed');
        }
    } catch (error) {
        document.getElementById('batch-error').textContent = error.message;
        document.getElementById('batch-error').style.display = 'block';
    } finally {
        document.getElementById('batch-loading').style.display = 'none';
    }
}

// ========================================
// RESULTS RENDERING
// ========================================

/**
 * Display assessment results
 */
function displayResults(data, resultsId, endpoint) {
    const resultsDiv = document.getElementById(resultsId);
    const assessment = data.assessment;

    let html = '<div class="results-header">';
    html += '<h2>Assessment Complete</h2>';

    const riskClass = 'risk-' + assessment.risk_level.replace(/_/g, '-');
    html += `<div class="risk-badge ${riskClass}">${assessment.risk_level.replace(/_/g, ' ')}</div>`;
    html += '</div>';

    html += '<div class="stats-grid">';

    if (assessment.confidence_interval) {
        const ci = assessment.confidence_interval;
        html += `
            <div class="stat-card">
                <div class="stat-label">Vulnerability Index</div>
                <div class="stat-value">${ci.point_estimate}</div>
                <p style="font-size: 0.85em; color: #64748b; margin-top: 0.5rem;">
                    95% CI: ${ci.lower_bound_95}–${ci.upper_bound_95}
                </p>
            </div>
        `;
    } else {
        html += `
            <div class="stat-card">
                <div class="stat-label">Vulnerability Index</div>
                <div class="stat-value">${assessment.vulnerability_index}</div>
            </div>
        `;
    }

    html += `
        <div class="stat-card">
            <div class="stat-label">Elevation</div>
            <div class="stat-value">${assessment.elevation_m}m</div>
        </div>
    `;

    if (assessment.distance_to_water_m !== null) {
        html += `
            <div class="stat-card">
                <div class="stat-label">Distance to Water</div>
                <div class="stat-value">${assessment.distance_to_water_m}m</div>
            </div>
        `;
    }

    html += '</div>';

    if (assessment.uncertainty_analysis) {
        const ua = assessment.uncertainty_analysis;
        const confidenceValue = parseFloat(ua.confidence) || 0;
        const barWidth = Math.round(confidenceValue * 100);

        let confidenceClass = 'confidence-low-fill';
        if (confidenceValue >= 0.75) confidenceClass = 'confidence-high';
        else if (confidenceValue >= 0.55) confidenceClass = 'confidence-moderate-fill';

        html += `
            <div class="confidence-section">
                <h3>Assessment Confidence</h3>
                <div class="confidence-bar-wrapper">
                    <span>Low</span>
                    <div class="confidence-bar">
                        <div class="confidence-fill ${confidenceClass}" style="width: ${barWidth}%;"></div>
                        <span class="confidence-text">${barWidth}%</span>
                    </div>
                    <span>High</span>
                </div>
                <p style="margin-top: 1rem; color: #94a3b8; font-style: italic;">
                    ${ua.interpretation}
                </p>
            </div>
        `;

        if (ua.data_quality_flags && ua.data_quality_flags.length > 0) {
            const criticalFlags = ua.data_quality_flags.filter(flag =>
                flag === 'steep_terrain_dem_error_high' ||
                flag === 'coastal_surge_risk_not_modeled'
            );

            if (criticalFlags.length > 0) {
                html += '<div class="quality-warning"><h4>⚠ Data Quality Notes</h4><ul>';
                criticalFlags.forEach(flag => {
                    html += `<li>${formatFlag(flag)}</li>`;
                });
                html += '</ul></div>';
            }
        }
    }

    html += '<div class="detail-section"><h3>Terrain Analysis</h3>';
    html += `
        <div class="metric-row">
            <span class="metric-label">Elevation</span>
            <span class="metric-value">${assessment.elevation_m} m</span>
        </div>
        <div class="metric-row">
            <span class="metric-label">Relative Elevation (TPI)</span>
            <span class="metric-value">${assessment.relative_elevation_m !== null ? assessment.relative_elevation_m + ' m' : 'N/A'}</span>
        </div>
        <div class="metric-row">
            <span class="metric-label">Slope</span>
            <span class="metric-value">${assessment.slope_degrees !== null ? assessment.slope_degrees + '°' : 'N/A'}</span>
        </div>
        <div class="metric-row">
            <span class="metric-label">Distance to Water</span>
            <span class="metric-value">${assessment.distance_to_water_m !== null ? assessment.distance_to_water_m + ' m' : 'N/A'}</span>
        </div>
    `;
    html += '</div>';

    if (assessment.hazard_breakdown) {
        const hb = assessment.hazard_breakdown;
        html += '<div class="detail-section"><h3>Hazard Breakdown</h3>';
        html += '<div class="hazard-grid">';
        html += `
            <div class="hazard-card">
                <div class="hazard-type">Fluvial/Riverine</div>
                <div class="hazard-value">${hb.fluvial_riverine}</div>
            </div>
            <div class="hazard-card">
                <div class="hazard-type">Coastal Surge</div>
                <div class="hazard-value">${hb.coastal_surge}</div>
            </div>
            <div class="hazard-card">
                <div class="hazard-type">Pluvial/Drainage</div>
                <div class="hazard-value">${hb.pluvial_drainage}</div>
            </div>
        `;
        html += '</div>';
        html += `<p style="margin-top: 1.5rem;"><strong>Dominant Hazard:</strong> ${assessment.dominant_hazard.replace(/_/g, ' ').toUpperCase()}</p>`;
        html += '</div>';
    }

    if (data.explanation) {
        const exp = data.explanation;
        html += '<div class="explanation-section">';
        html += '<h3>Risk Factor Analysis</h3>';
        html += `<p style="margin-bottom: 1.5rem; color: #cbd5e1;"><strong>Top Risk Driver:</strong> ${exp.top_risk_driver}</p>`;

        exp.explanations.forEach(factor => {
            html += `
                <div class="factor-item">
                    <span class="factor-name">${factor.factor}</span>
                    <div class="factor-bar">
                        <div class="factor-fill" style="width: ${factor.contribution_pct}%"></div>
                    </div>
                    <span class="factor-percentage">${factor.contribution_pct}%</span>
                </div>
            `;
        });

        html += '</div>';
    }

    resultsDiv.innerHTML = html;
    resultsDiv.style.display = 'block';
}

// ========================================
// INITIALIZATION
// ========================================

document.addEventListener('DOMContentLoaded', () => {
    // Initialize cache and autofill
    updateDatalistSuggestions();
    setupAutoFill();

    // Setup predict height buttons
    const buttons = document.querySelectorAll('.predict-height-btn');
    if (buttons.length > 0) {
        buttons.forEach(button => {
            const latId = button.dataset.latId;
            const lonId = button.dataset.lonId;
            const heightId = button.dataset.heightId;
            const errorId = button.dataset.errorId;

            button.addEventListener('click', () => {
                predictHeight(latId, lonId, heightId, errorId, button);
            });
        });
    }

    // Setup GBA height buttons
    document.querySelectorAll('.gba-height-btn').forEach(btn => {
        btn.addEventListener('click', () => {
            getHeightFromGBA(
                btn.dataset.latId,
                btn.dataset.lonId,
                btn.dataset.heightId,
                btn.dataset.errorId,
                btn
            );
        });
    });
});