document.addEventListener('DOMContentLoaded', () => {
    const navLinks = document.querySelectorAll('header nav a');
    navLinks.forEach(link => {
        link.addEventListener('click', function(event) {
            event.stopImmediatePropagation();
            window.location.href = this.href;
        }, true); 
    });
    
    console.log('Landing page loaded.');
    
    // Animate elements on scroll using Intersection Observer
    const animatedElements = document.querySelectorAll('.animate-on-scroll');
    const observer = new IntersectionObserver(entries => {
        entries.forEach(entry => {
            if (entry.isIntersecting) {
                entry.target.classList.add('animate-fadeIn');
                observer.unobserve(entry.target);
            }
        });
    }, { threshold: 0.2 });
    
    animatedElements.forEach(el => observer.observe(el));

    // Plotly initial plot (if present)
    const initialPlotDiv = document.getElementById('initialPlot');
    if (initialPlotDiv) {
        const plotData = JSON.parse(initialPlotDiv.dataset.plot);
        Plotly.newPlot('plotDiv', plotData.data, plotData.layout);
    }

    // Initialize toast notifications
    if (!document.getElementById('toast-container')) {
        const toastContainer = document.createElement('div');
        toastContainer.id = 'toast-container';
        toastContainer.className = 'fixed top-4 right-4 z-50';
        document.body.appendChild(toastContainer);
    }
});

function showToast(message, type = 'success') {
    const toast = document.createElement('div');
    toast.className = `p-4 mb-4 rounded shadow-lg ${type === 'success' ? 'bg-green-500' : 'bg-red-500'} text-white`;
    toast.textContent = message;
    
    const container = document.getElementById('toast-container');
    container.appendChild(toast);
    
    setTimeout(() => {
        toast.remove();
    }, 3000);
}

window.createPlot = function() {
    const column = document.getElementById('plotColumn').value;
    const plotType = document.getElementById('plotType').value;
    
    fetch('/forecast/sales/plot', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/x-www-form-urlencoded',
        },
        body: `column=${column}&plot_type=${plotType}`
    })
    .then(response => response.json())
    .then(data => {
        if (data.success) {
            const plotData = JSON.parse(data.plot);
            Plotly.newPlot('plotDiv', plotData.data, plotData.layout);
            showToast(`Generated ${plotType} for ${column}`);
        } else {
            showToast(data.error, 'error');
        }
    })
    .catch(error => {
        console.error('Error:', error);
        showToast(error.message, 'error');
    });
}

window.fixNulls = function(column) {
    const method = document.getElementById('method-' + column).value;
    fetch('/forecast/sales/fix_nulls', {
        method: 'POST',
        headers: {'Content-Type': 'application/x-www-form-urlencoded'},
        body: `column=${column}&method=${method}`
    })
    .then(response => response.json())
    .then(data => {
        const msgDiv = document.getElementById('null-fix-message');
        if (data.success) {
            msgDiv.textContent = data.message;
            msgDiv.classList.remove('text-red-700');
            msgDiv.classList.add('text-green-700');
            showToast(data.message);

            // Update summary stats
            updateSummaryStats(data.summary_stats);

            // Update preview table
            updatePreviewTable(data.columns, data.preview_data);

            // Update nulls UI
            updateNullsUI(data.summary_stats.missing_values);

        } else {
            msgDiv.textContent = data.error;
            msgDiv.classList.remove('text-green-700');
            msgDiv.classList.add('text-red-700');
            showToast(data.error, 'error');
        }
    });
}

// Helper to update summary stats
function updateSummaryStats(stats) {
    document.querySelectorAll('.summary-total-rows').forEach(el => el.textContent = stats.total_rows);
    document.querySelectorAll('.summary-total-cols').forEach(el => el.textContent = stats.total_columns);
    document.querySelectorAll('.summary-numeric-cols').forEach(el => el.textContent = stats.numeric_columns.join(', '));
    document.querySelectorAll('.summary-categorical-cols').forEach(el => el.textContent = stats.categorical_columns.join(', '));
}

// Helper to update preview table
function updatePreviewTable(columns, previewData) {
    const table = document.getElementById('preview-table');
    if (!table) return;
    // Update header
    let thead = table.querySelector('thead');
    let tbody = table.querySelector('tbody');
    thead.innerHTML = '<tr>' + columns.map(col => `<th class="px-4 py-2 bg-gray-100">${col}</th>`).join('') + '</tr>';
    // Update body
    tbody.innerHTML = previewData.map(row =>
        '<tr>' + columns.map(col => `<td class="border px-4 py-2">${row[col]}</td>`).join('') + '</tr>'
    ).join('');
}

// Helper to update nulls UI
function updateNullsUI(missingValues) {
    const nullList = document.getElementById('null-list');
    if (!nullList) return;
    let html = '';
    let hasNulls = false;
    for (const [col, count] of Object.entries(missingValues)) {
        if (count > 0) {
            hasNulls = true;
            html += `
                <li>
                    <span>${col}: ${count} missing values</span>
                    <select id="method-${col}" class="border rounded p-1 mx-2">
                        <option value="drop">Drop Rows</option>
                        <option value="mean">Fill Mean</option>
                        <option value="median">Fill Median</option>
                        <option value="mode">Fill Mode</option>
                    </select>
                    <button class="btn-learn-more" onclick="fixNulls('${col}')">Fix</button>
                </li>
            `;
        }
    }
    nullList.innerHTML = html;
    // If no nulls left, show a message
    if (!hasNulls) {
        nullList.innerHTML = '<li class="text-green-700 font-semibold">No missing values remaining!</li>';
    }
}
window.runForecast = function() {
    const dateCol = document.getElementById('forecastDateCol').value;
    const targetCol = document.getElementById('forecastTargetCol').value;
    const model = document.getElementById('forecastModel').value;
    const horizon = document.getElementById('forecastHorizon').value;
    const metricsDiv = document.getElementById('forecast-metrics');
    const plotDiv = document.getElementById('forecast-plot');
    const errorDiv = document.getElementById('forecast-error');
    metricsDiv.innerHTML = '';
    plotDiv.innerHTML = '';
    errorDiv.textContent = '';

    fetch('/forecast/sales/run_forecast', {
        method: 'POST',
        headers: {'Content-Type': 'application/x-www-form-urlencoded'},
        body: `date_col=${dateCol}&target_col=${targetCol}&model=${model}&horizon=${horizon}`
    })
    .then(response => response.json())
    .then(data => {
        if (data.success) {
            // Show metrics
            metricsDiv.innerHTML = `
                <div class="mb-2">
                    <strong>Model:</strong> ${data.model}
                </div>
                <div class="mb-2">
                    <strong>MAPE:</strong> ${data.metrics.MAPE.toFixed(2)}%
                    <strong class="ml-4">RMSE:</strong> ${data.metrics.RMSE.toFixed(2)}
                    <strong class="ml-4">R²:</strong> ${data.metrics.R2.toFixed(3)}
                </div>
            `;
            // Plot forecast with confidence intervals
            const trace = {
                x: data.dates,
                y: data.forecast,
                mode: 'lines+markers',
                name: 'Forecast'
            };
            const lower = data.conf_int.map(ci => ci[0]);
            const upper = data.conf_int.map(ci => ci[1]);
            const ciTrace = {
                x: [...data.dates, ...data.dates.slice().reverse()],
                y: [...upper, ...lower.reverse()],
                fill: 'toself',
                fillcolor: 'rgba(0,100,80,0.2)',
                line: {color: 'transparent'},
                name: 'Confidence Interval',
                showlegend: true,
                type: 'scatter'
            };
            const layout = {
                title: 'Forecasted Sales',
                xaxis: {title: 'Date'},
                yaxis: {title: 'Forecast'},
                showlegend: true
            };
            Plotly.newPlot(plotDiv, [trace, ciTrace], layout);
            showToast('Forecast generated!');
        } else {
            errorDiv.textContent = data.error;
            showToast(data.error, 'error');
        }
    })
    .catch(error => {
        errorDiv.textContent = error.message;
        showToast(error.message, 'error');
    });
}

// Machine Failure Prediction

function runPrediction() {
    // Show loading state
    const metricsDiv = document.getElementById('predict-metrics');
    const errorDiv = document.getElementById('predict-error');
    const singlePredictionSection = document.getElementById('single-prediction-section');
    
    metricsDiv.innerHTML = '<p>Running prediction...</p>';
    errorDiv.textContent = '';
    singlePredictionSection.classList.add('hidden'); // Hide form until model is ready
    
    // Get selected values
    const targetCol = document.getElementById('predictTargetCol').value;
    const model = document.getElementById('predictModel').value; // Model is currently fixed to RF in backend, but UI allows selection
    
    // Create form data
    const formData = new FormData();
    formData.append('target_col', targetCol);
    formData.append('model', model);

    // Make API call
    fetch('/predict/machine_failure/run_prediction', {
        method: 'POST',
        body: formData
    })
    .then(response => response.json())
    .then(data => {
        if (data.success) {
          // Display metrics in a grid
          let metricsHtml =
            '<div class="grid grid-cols-2 md:grid-cols-4 gap-4">';
          for (const [key, value] of Object.entries(data.metrics)) {
            metricsHtml += `
                    <div class="p-4 bg-blue-50 rounded">
                        <p class="font-semibold">${key}</p>
                        <p class="text-xl">${value.toFixed(4)}</p>
                    </div>
                `;
          }
          metricsHtml += "</div>";
          metricsDiv.innerHTML = metricsHtml;

          // --- Feature Importance ---
          if (data.top_features && Array.isArray(data.top_features)) {
            const fiDiv = document.getElementById("feature-importance");
            const fiList = document.getElementById("feature-importance-list");
            fiDiv.classList.remove("hidden");
            fiList.innerHTML = `
                    <table class="min-w-full table-auto">
                        <thead>
                            <tr>
                                <th class="px-4 py-2 bg-gray-100">Feature</th>
                                <th class="px-4 py-2 bg-gray-100">Importance</th>
                            </tr>
                        </thead>
                        <tbody>
                            ${data.top_features
                              .map(
                                (f) =>
                                  `<tr>
                                    <td class="border px-4 py-2">${
                                      f.feature
                                    }</td>
                                    <td class="border px-4 py-2">${f.importance.toFixed(
                                      4
                                    )}</td>
                                </tr>`
                              )
                              .join("")}
                        </tbody>
                    </table>
                `;
          }

          showToast("Model trained successfully");

          // Now that the model is trained, fetch form data and display the single prediction form
          fetchSinglePredictionForm();
        } else {
            errorDiv.textContent = data.error || 'An error occurred';
            showToast(data.error || 'An error occurred', 'error');
        }
    })
    .catch(error => {
        errorDiv.textContent = 'Error: ' + error.message;
        showToast('Error: ' + error.message, 'error');
    });
}

window.runPrediction = runPrediction;

// Function to fetch data for and generate the single prediction form
function fetchSinglePredictionForm() {
    fetch('/predict/machine_failure/get_form_data')
        .then(response => response.json())
        .then(data => {
            if (data.success) {
                generatePredictionForm(data.form_fields);
                document.getElementById('single-prediction-section').classList.remove('hidden');
            } else {
                showToast(data.error, 'error');
                document.getElementById('single-prediction-error').textContent = data.error;
            }
        })
        .catch(error => {
            console.error('Error fetching form data:', error);
            showToast('Error fetching form data: ' + error.message, 'error');
            document.getElementById('single-prediction-error').textContent = 'Error fetching form data: ' + error.message;
        });
}

// Function to dynamically generate the prediction form
function generatePredictionForm(formFields) {
    const formContainer = document.getElementById('single-prediction-form');
    formContainer.innerHTML = ''; // Clear previous fields

    formFields.forEach(field => {
        const div = document.createElement('div');
        div.className = 'mb-4';

        const label = document.createElement('label');
        label.className = 'block text-gray-700 text-sm font-bold mb-2';
        label.textContent = field.name.replace(/_/g, ' ').replace(/\b\w/g, l => l.toUpperCase()); // Capitalize and replace underscores

        div.appendChild(label);

        if (field.type === 'select') {
            const select = document.createElement('select');
            select.id = `input-${field.name}`;
            select.name = field.name;
            select.className = 'shadow appearance-none border rounded w-full py-2 px-3 text-gray-700 leading-tight focus:outline-none focus:shadow-outline';
            
            field.options.forEach(option => {
                const optionElement = document.createElement('option');
                optionElement.value = option;
                optionElement.textContent = option;
                // Set default selected option
                if (field.default_value !== undefined && String(field.default_value) === String(option)) { // Compare as strings
                    optionElement.selected = true;
                }
                select.appendChild(optionElement);
            });
            div.appendChild(select);
        } else if (field.type === 'number') {
            const input = document.createElement('input');
            input.id = `input-${field.name}`;
            input.name = field.name;
            input.type = 'number';
            input.className = 'shadow appearance-none border rounded w-full py-2 px-3 text-gray-700 leading-tight focus:outline-none focus:shadow-outline';
            input.placeholder = `Enter ${field.name.replace(/_/g, ' ')}`;
            if (field.default_value !== undefined) {
                input.value = field.default_value;
            }
            div.appendChild(input);
        } else { // Default to text for other types, including timestamps
            const input = document.createElement('input');
            input.id = `input-${field.name}`;
            input.name = field.name;
            input.type = 'text';
            input.className = 'shadow appearance-none border rounded w-full py-2 px-3 text-gray-700 leading-tight focus:outline-none focus:shadow-outline';
            input.placeholder = field.placeholder || `Enter ${field.name.replace(/_/g, ' ')}`;
            if (field.default_value !== undefined) {
                input.value = field.default_value;
            }
            div.appendChild(input);
        }
        formContainer.appendChild(div);
    });
}

// Function to handle single instance prediction submission
window.predictSingleInstance = function() {
    const form = document.getElementById('single-prediction-form');
    const formData = {};
    const inputs = form.querySelectorAll('input, select');

    inputs.forEach(input => {
        formData[input.name] = input.value;
    });

    const resultDiv = document.getElementById('single-prediction-result');
    const predictionOutput = document.getElementById('prediction-output');
    const probabilityOutput = document.getElementById('probability-output');
    const errorDiv = document.getElementById('single-prediction-error');

    resultDiv.classList.add('hidden');
    errorDiv.textContent = '';
    predictionOutput.textContent = 'Predicting...';
    probabilityOutput.innerHTML = '';

    fetch('/predict/machine_failure/predict_single', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
        },
        body: JSON.stringify(formData)
    })
    .then(response => response.json())
    .then(data => {
        if (data.success) {
            let displayPrediction = 'Unknown';
            if (data.prediction === 0 || data.prediction === '0') {
                displayPrediction = 'No Failure';
            } else if (data.prediction === 1 || data.prediction === '1') {
                displayPrediction = 'Failure';
            } else {
                 displayPrediction = data.prediction; // Fallback for other values if backend sends different strings
            }
            predictionOutput.textContent = displayPrediction;

            if (data.probability && Array.isArray(data.probability)) {
                if (data.probability.length === 2) { // Binary classification
                    const probNoFailure = data.probability[0];
                    const probFailure = data.probability[1];
                    probabilityOutput.innerHTML = `Probability of No Failure: ${(probNoFailure * 100).toFixed(2)}%<br>
                                                 Probability of Failure: ${(probFailure * 100).toFixed(2)}%`;
                } else { // Multi-class classification
                    probabilityOutput.innerHTML = 'Probabilities: ' + data.probability.map((p, i) => `Class ${i}: ${(p * 100).toFixed(2)}%`).join(', ');
                }
            } else {
                 probabilityOutput.innerHTML = 'Probability: N/A (not a classification model)';
            }
            resultDiv.classList.remove('hidden');
            showToast('Single prediction successful!');
        } else {
            errorDiv.textContent = data.error || 'An error occurred during single prediction.';
            showToast(data.error || 'An error occurred', 'error');
        }
    })
    .catch(error => {
        console.error('Error during single prediction:', error);
        errorDiv.textContent = 'Error: ' + error.message;
        showToast('Error: ' + error.message, 'error');
    });
};


// Supply Failure Prediction (New functions similar to Machine Failure)

window.runSupplyPrediction = function() {
    const metricsDiv = document.getElementById('predict-metrics-supply');
    const errorDiv = document.getElementById('predict-error-supply');
    const singlePredictionSection = document.getElementById('single-prediction-section-supply');
    
    metricsDiv.innerHTML = '<p>Running prediction...</p>';
    errorDiv.textContent = '';
    singlePredictionSection.classList.add('hidden');
    
    // Target column is fixed to 'failure_flag'
    const targetCol = 'failure_flag'; 
    const model = document.getElementById('predictModelSupply').value; 
    
    const formData = new FormData();
    formData.append('target_col', targetCol);
    formData.append('model', model);

    fetch('/predict/supply_failure/run_prediction', {
        method: 'POST',
        body: formData
    })
    .then(response => response.json())
    .then(data => {
        if (data.success) {
          let metricsHtml =
            '<div class="grid grid-cols-2 md:grid-cols-4 gap-4">';
          for (const [key, value] of Object.entries(data.metrics)) {
            metricsHtml += `
                    <div class="p-4 bg-blue-50 rounded">
                        <p class="font-semibold">${key}</p>
                        <p class="text-xl">${value.toFixed(4)}</p>
                    </div>
                `;
          }
          metricsHtml += "</div>";
          metricsDiv.innerHTML = metricsHtml;

          // --- Feature Importance ---
          if (data.top_features && Array.isArray(data.top_features)) {
            const fiDiv = document.getElementById("feature-importance");
            const fiList = document.getElementById("feature-importance-list");
            fiDiv.classList.remove("hidden");
            fiList.innerHTML = `
                    <table class="min-w-full table-auto">
                        <thead>
                            <tr>
                                <th class="px-4 py-2 bg-gray-100">Feature</th>
                                <th class="px-4 py-2 bg-gray-100">Importance</th>
                            </tr>
                        </thead>
                        <tbody>
                            ${data.top_features
                              .map(
                                (f) =>
                                  `<tr>
                                    <td class="border px-4 py-2">${
                                      f.feature
                                    }</td>
                                    <td class="border px-4 py-2">${f.importance.toFixed(
                                      4
                                    )}</td>
                                </tr>`
                              )
                              .join("")}
                        </tbody>
                    </table>
                `;
          }

          showToast("Supply Model trained successfully");
          fetchSupplySinglePredictionForm();
        } else {
            errorDiv.textContent = data.error || 'An error occurred';
            showToast(data.error || 'An error occurred', 'error');
        }
    })
    .catch(error => {
        errorDiv.textContent = 'Error: ' + error.message;
        showToast('Error: ' + error.message, 'error');
    });
}

function fetchSupplySinglePredictionForm() {
    fetch('/predict/supply_failure/get_form_data')
        .then(response => response.json())
        .then(data => {
            if (data.success) {
                generateSupplyPredictionForm(data.form_fields);
                document.getElementById('single-prediction-section-supply').classList.remove('hidden');
            } else {
                showToast(data.error, 'error');
                document.getElementById('single-prediction-error-supply').textContent = data.error;
            }
        })
        .catch(error => {
            console.error('Error fetching supply form data:', error);
            showToast('Error fetching supply form data: ' + error.message, 'error');
            document.getElementById('single-prediction-error-supply').textContent = 'Error fetching supply form data: ' + error.message;
        });
}

function generateSupplyPredictionForm(formFields) {
    const formContainer = document.getElementById('single-prediction-form-supply');
    formContainer.innerHTML = '';

    formFields.forEach(field => {
        const div = document.createElement('div');
        div.className = 'mb-4';

        const label = document.createElement('label');
        label.className = 'block text-gray-700 text-sm font-bold mb-2';
        label.textContent = field.name.replace(/_/g, ' ').replace(/\b\w/g, l => l.toUpperCase());

        div.appendChild(label);

        if (field.type === 'select') {
            const select = document.createElement('select');
            select.id = `input-supply-${field.name}`;
            select.name = field.name;
            select.className = 'shadow appearance-none border rounded w-full py-2 px-3 text-gray-700 leading-tight focus:outline-none focus:shadow-outline';
            
            field.options.forEach(option => {
                const optionElement = document.createElement('option');
                optionElement.value = option;
                optionElement.textContent = option;
                if (field.default_value !== undefined && String(field.default_value) === String(option)) {
                    optionElement.selected = true;
                }
                select.appendChild(optionElement);
            });
            div.appendChild(select);
        } else if (field.type === 'number') {
            const input = document.createElement('input');
            input.id = `input-supply-${field.name}`;
            input.name = field.name;
            input.type = 'number';
            input.className = 'shadow appearance-none border rounded w-full py-2 px-3 text-gray-700 leading-tight focus:outline-none focus:shadow-outline';
            input.placeholder = `Enter ${field.name.replace(/_/g, ' ')}`;
            if (field.default_value !== undefined) {
                input.value = field.default_value;
            }
            div.appendChild(input);
        } else { // Default to text for other types, including timestamps
            const input = document.createElement('input');
            input.id = `input-supply-${field.name}`;
            input.name = field.name;
            input.type = 'text';
            input.className = 'shadow appearance-none border rounded w-full py-2 px-3 text-gray-700 leading-tight focus:outline-none focus:shadow-outline';
            input.placeholder = field.placeholder || `Enter ${field.name.replace(/_/g, ' ')}`;
            if (field.default_value !== undefined) {
                input.value = field.default_value;
            }
            div.appendChild(input);
        }
        formContainer.appendChild(div);
    });
}

window.predictSupplySingleInstance = function() {
    const form = document.getElementById('single-prediction-form-supply');
    const formData = {};
    const inputs = form.querySelectorAll('input, select');

    inputs.forEach(input => {
        formData[input.name] = input.value;
    });

    const resultDiv = document.getElementById('single-prediction-result-supply');
    const predictionOutput = document.getElementById('prediction-output-supply');
    const probabilityOutput = document.getElementById('probability-output-supply');
    const errorDiv = document.getElementById('single-prediction-error-supply');

    resultDiv.classList.add('hidden');
    errorDiv.textContent = '';
    predictionOutput.textContent = 'Predicting...';
    probabilityOutput.innerHTML = '';

    fetch('/predict/supply_failure/predict_single', {
        method: 'POST',
        headers: {
            'Content-Type': 'application/json',
        },
        body: JSON.stringify(formData)
    })
    .then(response => response.json())
    .then(data => {
        if (data.success) {
            // User-friendly mapping for Supply Failure
            let displayPrediction = 'Unknown';
            if (data.prediction === "Delivery Successful") { // Backend sends "Delivery Successful" or "Delivery Failed"
                displayPrediction = 'Delivery Successful';
            } else if (data.prediction === "Delivery Failed") {
                displayPrediction = 'Delivery Failed';
            } else {
                 displayPrediction = data.prediction; // Fallback
            }
            predictionOutput.textContent = displayPrediction;

            if (data.probability && Array.isArray(data.probability)) {
                if (data.probability.length === 2) {
                    // Assuming data.probability[0] corresponds to 'Delivery Successful' and data.probability[1] to 'Delivery Failed'
                    const probSuccessful = data.probability[0];
                    const probFailed = data.probability[1];
                    probabilityOutput.innerHTML = `Probability of Delivery Successful: ${(probSuccessful * 100).toFixed(2)}%<br>
                                                 Probability of Delivery Failed: ${(probFailed * 100).toFixed(2)}%`;
                } else {
                    probabilityOutput.innerHTML = 'Probabilities: ' + data.probability.map((p, i) => `Class ${i}: ${(p * 100).toFixed(2)}%`).join(', ');
                }
            } else {
                 probabilityOutput.innerHTML = 'Probability: N/A (not a classification model)';
            }
            resultDiv.classList.remove('hidden');
            showToast('Single prediction successful!');
        } else {
            errorDiv.textContent = data.error || 'An error occurred during single prediction.';
            showToast(data.error || 'An error occurred', 'error');
        }
    })
    .catch(error => {
        console.error('Error during single prediction:', error);
        errorDiv.textContent = 'Error: ' + error.message;
        showToast('Error: ' + error.message, 'error');
    });
};