// State
let selectedFile = null;
let projects = {};
let lastEvents = [];
let previewData = [];

// DOM Elements
const uploadZone = document.getElementById('uploadZone');
const fileInput = document.getElementById('fileInput');
const browseLink = document.getElementById('browseLink');
const filePreview = document.getElementById('filePreview');
const fileName = document.getElementById('fileName');
const fileSize = document.getElementById('fileSize');
const removeFileBtn = document.getElementById('removeFile');
const projectSelect = document.getElementById('projectSelect');
const submitBtn = document.getElementById('submitBtn');
const statusBadge = document.getElementById('statusBadge');
const resultsSection = document.getElementById('resultsSection');
const resultsContent = document.getElementById('resultsContent');
const projectsList = document.getElementById('projectsList');
const refreshProjectsBtn = document.getElementById('refreshProjects');
const loadingOverlay = document.getElementById('loadingOverlay');
const toastContainer = document.getElementById('toastContainer');
const startDateInput = document.getElementById('startDate');
const endDateInput = document.getElementById('endDate');
const loadEventsBtn = document.getElementById('loadEvents');
const approveEventsBtn = document.getElementById('approveEvents');
const eventsList = document.getElementById('eventsList');
const eventsTotal = document.getElementById('eventsTotal');

// Initialize
document.addEventListener('DOMContentLoaded', () => {
    checkHealth();
    loadProjects();
    setDefaultDateRange();
    setupEventListeners();
});

// Event Listeners
function setupEventListeners() {
    // File upload
    uploadZone.addEventListener('click', () => fileInput.click());
    browseLink.addEventListener('click', (e) => {
        e.stopPropagation();
        fileInput.click();
    });
    fileInput.addEventListener('change', handleFileSelect);
    removeFileBtn.addEventListener('click', (e) => {
        e.stopPropagation();
        removeFile();
    });

    // Drag and drop
    uploadZone.addEventListener('dragover', handleDragOver);
    uploadZone.addEventListener('dragleave', handleDragLeave);
    uploadZone.addEventListener('drop', handleDrop);

    // Submit
    submitBtn.addEventListener('click', handleSubmit);

    // Refresh projects
    refreshProjectsBtn.addEventListener('click', () => {
        refreshProjectsBtn.classList.add('spin');
        loadProjects().finally(() => {
            setTimeout(() => refreshProjectsBtn.classList.remove('spin'), 500);
        });
    });
    
    // Approvals
    loadEventsBtn.addEventListener('click', fetchEvents);
    approveEventsBtn.addEventListener('click', approveEvents);
}

// API Functions
async function checkHealth() {
    try {
        const response = await fetch('/health');
        const data = await response.json();
        
        const statusText = statusBadge.querySelector('.status-text');
        
        if (data.status === 'healthy') {
            statusBadge.classList.add('healthy');
            statusText.textContent = 'Connected';
        } else {
            statusBadge.classList.add('unhealthy');
            statusText.textContent = 'No API Key';
            showToast('Please configure KLEER_API_KEY environment variable', 'warning');
        }
    } catch (error) {
        statusBadge.classList.add('unhealthy');
        statusBadge.querySelector('.status-text').textContent = 'Offline';
        showToast('Cannot connect to server', 'error');
    }
}

async function loadProjects() {
    try {
        const response = await fetch('/projects');
        
        if (!response.ok) {
            throw new Error(`HTTP ${response.status}`);
        }
        
        projects = await response.json();
        populateProjectSelect();
        displayProjects();
    } catch (error) {
        console.error('Error loading projects:', error);
        projectSelect.innerHTML = '<option value="">Failed to load projects</option>';
        projectsList.innerHTML = `<div class="loading" style="color: var(--danger);">Failed to load projects: ${error.message}</div>`;
        showToast('Failed to load projects', 'error');
    }
}

function populateProjectSelect() {
    projectSelect.innerHTML = '<option value="">Select a project...</option>';
    
    Object.keys(projects).forEach(projectName => {
        const option = document.createElement('option');
        option.value = projectName;
        option.textContent = projectName;
        projectSelect.appendChild(option);
    });
    
    projectSelect.disabled = false;
    updateSubmitButton();
}

function displayProjects() {
    const projectNames = Object.keys(projects);
    
    if (projectNames.length === 0) {
        projectsList.innerHTML = '<div class="loading">No projects found</div>';
        return;
    }
    
    projectsList.innerHTML = '';
    
    projectNames.forEach(projectName => {
        const project = projects[projectName];
        const projectItem = document.createElement('div');
        projectItem.className = 'project-item';
        projectItem.innerHTML = `
            <div class="project-name">${projectName}</div>
            <div class="project-meta">
                <span>ID: ${project.id}</span>
                <span>Activity: ${project.activity.id || 'N/A'}</span>
            </div>
        `;
        projectsList.appendChild(projectItem);
    });
}

// File Handling
function handleFileSelect(e) {
    const file = e.target.files[0];
    if (file) {
        if (isSupportedFile(file.name)) {
            setFile(file);
        } else {
            showToast('Please select a CSV or XLSX file', 'warning');
            fileInput.value = '';
        }
    }
}

function handleDragOver(e) {
    e.preventDefault();
    uploadZone.classList.add('drag-over');
}

function handleDragLeave(e) {
    e.preventDefault();
    uploadZone.classList.remove('drag-over');
}

function handleDrop(e) {
    e.preventDefault();
    uploadZone.classList.remove('drag-over');
    
    const file = e.dataTransfer.files[0];
    if (file) {
        if (isSupportedFile(file.name)) {
            setFile(file);
        } else {
            showToast('Please drop a CSV or XLSX file', 'warning');
        }
    }
}

function isSupportedFile(fileName) {
    const lower = fileName.toLowerCase();
    return lower.endsWith('.csv') || lower.endsWith('.xlsx');
}

function setFile(file) {
    selectedFile = file;
    
    // Show file preview
    uploadZone.style.display = 'none';
    filePreview.style.display = 'block';
    fileName.textContent = file.name;
    fileSize.textContent = formatFileSize(file.size);
    
    updateSubmitButton();
    generatePreview(file);
}

async function generatePreview(file) {
    const formData = new FormData();
    formData.append('file', file);
    
    showLoading(true);
    try {
        const response = await fetch('/preview-time', {
            method: 'POST',
            body: formData
        });
        const data = await response.json();
        
        if (!response.ok) {
            throw new Error(data.detail || `HTTP ${response.status}`);
        }
        
        renderPreview(data);
    } catch (error) {
        console.error('Preview error:', error);
        showToast('Failed to generate preview: ' + error.message, 'error');
        document.getElementById('previewContainer').style.display = 'none';
    } finally {
        showLoading(false);
    }
}

function renderPreview(data) {
    previewData = data.map(item => ({...item, selected: true}));
    const container = document.getElementById('previewContainer');
    container.style.display = 'block';
    
    updatePreviewTable();
    
    document.getElementById('selectAllPreview').onchange = (e) => {
        const checked = e.target.checked;
        previewData.forEach(item => item.selected = checked);
        updatePreviewTable();
    };
}

// Ensure togglePreviewItem is available globally for inline onclick handlers
window.togglePreviewItem = function(index) {
    previewData[index].selected = !previewData[index].selected;
    
    // Update "select all" checkbox state
    const allSelected = previewData.every(item => item.selected);
    const noneSelected = previewData.every(item => !item.selected);
    const selectAllCheckbox = document.getElementById('selectAllPreview');
    selectAllCheckbox.checked = allSelected;
    selectAllCheckbox.indeterminate = !allSelected && !noneSelected;
    
    updatePreviewTable();
};

function updatePreviewTable() {
    const tbody = document.getElementById('previewTableBody');
    tbody.innerHTML = '';
    let totalHours = 0;
    let selectedCount = 0;
    
    previewData.forEach((item, index) => {
        if (item.selected) {
            totalHours += item.hours;
            selectedCount++;
        }
        
        const tr = document.createElement('tr');
        if (!item.selected) tr.classList.add('excluded');
        
        tr.innerHTML = `
            <td><input type="checkbox" ${item.selected ? 'checked' : ''} onclick="event.stopPropagation(); togglePreviewItem(${index})"></td>
            <td>${item.date}</td>
            <td>${item.hours.toFixed(2)}</td>
        `;
        
        tr.onclick = () => togglePreviewItem(index);
        tbody.appendChild(tr);
    });
    
    document.getElementById('previewTotalHours').textContent = totalHours.toFixed(2);
    updateSubmitButton();
}

function removeFile() {
    selectedFile = null;
    previewData = [];
    fileInput.value = '';
    uploadZone.style.display = 'block';
    filePreview.style.display = 'none';
    document.getElementById('previewContainer').style.display = 'none';
    updateSubmitButton();
}

function updateSubmitButton() {
    const hasSelectedDates = previewData.length === 0 || previewData.some(item => item.selected);
    submitBtn.disabled = !(selectedFile && projectSelect.value && hasSelectedDates);
}

function setDefaultDateRange() {
    const today = new Date();
    const start = new Date(today);
    start.setDate(today.getDate() - 7);
    
    startDateInput.value = start.toISOString().slice(0, 10);
    endDateInput.value = today.toISOString().slice(0, 10);
}

// Submit Handler
async function handleSubmit() {
    if (!selectedFile || !projectSelect.value) {
        showToast('Please select a file and project', 'warning');
        return;
    }
    
    const formData = new FormData();
    formData.append('file', selectedFile);
    
    const projectName = projectSelect.value;
    
    const excludedDates = previewData
        .filter(item => !item.selected)
        .map(item => item.date)
        .join(',');
    
    showLoading(true);
    
    try {
        const url = `/report-time?project_name=${encodeURIComponent(projectName)}&excluded_dates=${encodeURIComponent(excludedDates)}`;
        const response = await fetch(url, {
            method: 'POST',
            body: formData
        });
        
        const data = await response.json();
        
        if (!response.ok) {
            throw new Error(data.detail || `HTTP ${response.status}`);
        }
        
        // Show success
        displayResults(data);
        showToast('Time reported successfully!', 'success');
        
        // Reset form
        removeFile();
        projectSelect.value = '';
        updateSubmitButton();
        
    } catch (error) {
        console.error('Error submitting:', error);
        showToast(`Error: ${error.message}`, 'error');
    } finally {
        showLoading(false);
    }
}

// Results Display
function displayResults(data) {
    resultsContent.innerHTML = `
        <div class="result-success">
            <h3>
                <svg width="24" height="24" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
                    <path d="M22 11.08V12a10 10 0 1 1-5.93-9.14"></path>
                    <polyline points="22 4 12 14.01 9 11.01"></polyline>
                </svg>
                ${data.message}
            </h3>
            <div class="result-stats">
                <div class="stat-item">
                    <div class="stat-value">${data.reported_days}</div>
                    <div class="stat-label">Days Reported</div>
                </div>
                <div class="stat-item">
                    <div class="stat-value">${data.total_hours.toFixed(2)}</div>
                    <div class="stat-label">Total Hours</div>
                </div>
                <div class="stat-item">
                    <div class="stat-value">${data.project_name}</div>
                    <div class="stat-label">Project</div>
                </div>
                <div class="stat-item">
                    <div class="stat-value">${data.user_name}</div>
                    <div class="stat-label">User</div>
                </div>
            </div>
        </div>
    `;
    
    resultsSection.style.display = 'block';
    resultsSection.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
}

// Utility Functions
function formatFileSize(bytes) {
    if (bytes === 0) return '0 Bytes';
    const k = 1024;
    const sizes = ['Bytes', 'KB', 'MB', 'GB'];
    const i = Math.floor(Math.log(bytes) / Math.log(k));
    return Math.round(bytes / Math.pow(k, i) * 100) / 100 + ' ' + sizes[i];
}

function showLoading(show) {
    loadingOverlay.style.display = show ? 'flex' : 'none';
}

function showToast(message, type = 'info') {
    const toast = document.createElement('div');
    toast.className = `toast ${type}`;
    toast.innerHTML = `
        <svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
            ${getToastIcon(type)}
        </svg>
        <span>${message}</span>
    `;
    
    toastContainer.appendChild(toast);
    
    setTimeout(() => {
        toast.style.animation = 'slideInRight 0.3s ease reverse';
        setTimeout(() => toast.remove(), 300);
    }, 3000);
}

function getToastIcon(type) {
    const icons = {
        success: '<path d="M22 11.08V12a10 10 0 1 1-5.93-9.14"></path><polyline points="22 4 12 14.01 9 11.01"></polyline>',
        error: '<circle cx="12" cy="12" r="10"></circle><line x1="15" y1="9" x2="9" y2="15"></line><line x1="9" y1="9" x2="15" y2="15"></line>',
        warning: '<path d="M10.29 3.86L1.82 18a2 2 0 0 0 1.71 3h16.94a2 2 0 0 0 1.71-3L13.71 3.86a2 2 0 0 0-3.42 0z"></path><line x1="12" y1="9" x2="12" y2="13"></line><line x1="12" y1="17" x2="12.01" y2="17"></line>',
        info: '<circle cx="12" cy="12" r="10"></circle><line x1="12" y1="16" x2="12" y2="12"></line><line x1="12" y1="8" x2="12.01" y2="8"></line>'
    };
    return icons[type] || icons.info;
}

// Project select change handler
projectSelect.addEventListener('change', updateSubmitButton);

// Approvals helpers
function renderEvents(events) {
    if (!events || events.length === 0) {
        eventsList.innerHTML = '<div class="loading">No events found for range</div>';
        eventsTotal.style.display = 'none';
        return;
    }
    
    let totalHours = 0;
    eventsList.innerHTML = '';
    events.forEach(event => {
        const approved = event.approved;
        const hours = parseFloat(event.hours) || 0;
        totalHours += hours;
        
        const item = document.createElement('div');
        item.className = 'event-item';
        item.innerHTML = `
            <div>
                <div class="project-name">${event.date || 'Unknown date'}</div>
                <div class="event-meta">
                    <span>Hours: ${hours.toFixed(2)}</span>
                    <span>Activity: ${event.activity?.id ?? '-'}</span>
                    <span>Project: ${event["client-project"]?.id ?? '-'}</span>
                </div>
            </div>
            <div class="event-status ${approved ? 'approved' : 'pending'}">
                ${approved ? 'Approved' : 'Pending'}
            </div>
        `;
        eventsList.appendChild(item);
    });

    eventsTotal.innerHTML = `Total Hours: <strong>${totalHours.toFixed(2)}</strong>`;
    eventsTotal.style.display = 'block';
}

function getDateRange() {
    const startDate = startDateInput.value;
    const endDate = endDateInput.value;
    
    if (!startDate || !endDate) {
        showToast('Please select start and end dates', 'warning');
        return null;
    }
    if (new Date(startDate) > new Date(endDate)) {
        showToast('Start date cannot be after end date', 'warning');
        return null;
    }
    return { startDate, endDate };
}

async function fetchEvents() {
    const range = getDateRange();
    if (!range) return;
    
    showLoading(true);
    try {
        const response = await fetch(`/events?start_date=${range.startDate}&end_date=${range.endDate}`);
        const data = await response.json();
        
        if (!response.ok) {
            throw new Error(data.detail || `HTTP ${response.status}`);
        }
        
        lastEvents = data.events || [];
        renderEvents(lastEvents);
        showToast('Events loaded', 'success');
    } catch (error) {
        console.error('Error fetching events:', error);
        showToast(`Failed to load events: ${error.message}`, 'error');
    } finally {
        showLoading(false);
    }
}

async function approveEvents() {
    const range = getDateRange();
    if (!range) return;
    
    showLoading(true);
    try {
        const response = await fetch(
            `/approve-events?start_date=${range.startDate}&end_date=${range.endDate}`,
            { method: 'POST' }
        );
        const data = await response.json();
        
        if (!response.ok) {
            throw new Error(data.detail || `HTTP ${response.status}`);
        }
        
        showToast('Events approved', 'success');
        await fetchEvents();
    } catch (error) {
        console.error('Error approving events:', error);
        showToast(`Failed to approve events: ${error.message}`, 'error');
    } finally {
        showLoading(false);
    }
}