{% extends "base.html" %}

{% block title %}Master Excel Files{% endblock %}

{% block content %}
<div class="container mt-4">
    <div class="d-flex justify-content-between align-items-center mb-4">
        <h1>Master Excel Files</h1>
        <div>
            <button id="download-template-btn" class="btn btn-outline-primary me-2" onclick="downloadTemplateWithFetch(event)">
                <i class="fas fa-download" id="download-icon"></i>
                <span id="download-text">Download Template</span>
            </button>
            <a href="{% url 'master-excel-create' %}" class="btn btn-primary">
                <i class="fas fa-plus"></i> Upload New
            </a>
        </div>
    </div>

    {% if messages %}
    <div class="messages mb-4">
        {% for message in messages %}
        <div class="alert alert-{{ message.tags }} alert-dismissible fade show" role="alert">
            {{ message }}
            <button type="button" class="btn-close" data-bs-dismiss="alert" aria-label="Close"></button>
        </div>
        {% endfor %}
    </div>
    {% endif %}


    <!-- Example Files Section -->
    {% if example_files %}
    <div class="card mb-4">
        <div class="card-header">
            <h3 class="card-title mb-0">
                <i class="fas fa-star text-warning"></i> Example Files
            </h3>
            <small class="text-muted">Pre-configured master Excel files for common scenarios</small>
        </div>
        <div class="card-body">
            <div class="table-responsive">
                <table class="table table-striped table-hover">
                    <thead>
                        <tr>
                            <th>Name</th>
                            <th>Description</th>
                            <th>Status</th>
                            <th>Actions</th>
                        </tr>
                    </thead>
                    <tbody>
                        {% for file in example_files %}
                        <tr>
                            <td>
                                <a href="{% url 'master-excel-detail' pk=file.pk %}">
                                    <i class="fas fa-star text-warning me-1"></i>
                                    {{ file.name }}
                                </a>
                            </td>
                            <td>{{ file.description|truncatewords:10 }}</td>
                            <td>
                                {% if file.validation_status == 'valid' %}
                                    <span class="badge bg-success">Valid</span>
                                {% elif file.validation_status == 'warnings' %}
                                    <span class="badge bg-warning">Valid with Warnings</span>
                                {% elif file.validation_status == 'invalid' %}
                                    <span class="badge bg-danger">Invalid</span>
                                {% else %}
                                    <span class="badge bg-secondary">Pending</span>
                                {% endif %}
                            </td>
                            <td>
                                <a href="{% url 'master-excel-download' pk=file.pk %}" class="btn btn-sm btn-outline-primary">
                                    <i class="fas fa-download"></i> Download
                                </a>
                            </td>
                        </tr>
                        {% endfor %}
                    </tbody>
                </table>
            </div>
        </div>
    </div>
    {% endif %}

    <!-- User Files Section -->
    <div class="card">
        <div class="card-header">
            <h3 class="card-title mb-0">
                <i class="fas fa-user"></i> Your Master Excel Files
            </h3>
            <small class="text-muted">Custom master Excel files you've uploaded</small>
        </div>
        <div class="card-body">
            {% if user_files %}
            <div class="table-responsive">
                <table class="table table-striped table-hover">
                    <thead>
                        <tr>
                            <th>ID</th>
                            <th>Name</th>
                            <th>Description</th>
                            <th>Status</th>
                            <th>Uploaded</th>
                            <th>Actions</th>
                        </tr>
                    </thead>
                    <tbody>
                        {% for file in user_files %}
                        <tr>
                            <td class="text-muted">{{ file.pk }}</td>
                            <td>
                                <a href="{% url 'master-excel-detail' pk=file.pk %}">
                                    {{ file.name }}
                                </a>
                            </td>
                            <td>{{ file.description|truncatewords:10 }}</td>
                            <td>
                                <div class="d-flex flex-wrap gap-1 align-items-center">
                                    {% if file.validation_status == 'valid' %}
                                        <span class="badge bg-success">Valid</span>
                                    {% elif file.validation_status == 'warnings' %}
                                        <span class="badge bg-warning">Valid with Warnings</span>
                                    {% elif file.validation_status == 'invalid' %}
                                        <span class="badge bg-danger">Invalid</span>
                                    {% else %}
                                        <span class="badge bg-secondary">Pending</span>
                                    {% endif %}
                                    {% if file.pk in files_with_preparations %}
                                        <span class="badge bg-info" title="Data already prepared">
                                            <i class="fas fa-check"></i> Prepared
                                        </span>
                                    {% endif %}
                                </div>
                            </td>
                            <td>{{ file.created_at|date:"Y-m-d H:i" }}</td>
                            <td>
                                <div class="d-flex flex-wrap gap-1">
                                    <a href="{% url 'master-excel-update' pk=file.pk %}" class="btn btn-sm btn-primary">
                                        <i class="fas fa-edit"></i> Edit
                                    </a>
                                    <a href="{% url 'master-excel-delete' pk=file.pk %}" class="btn btn-sm btn-danger">
                                        <i class="fas fa-trash"></i> Delete
                                    </a>
                                    {% if file.validation_status == 'valid' or file.validation_status == 'warnings' %}
                                        {% if file.pk not in files_with_preparations %}
                                        <form method="post" action="{% url 'prepare-data-with-master-excel' pk=file.pk %}" class="d-inline">
                                            {% csrf_token %}
                                            <button type="submit" class="btn btn-sm btn-success">
                                                <i class="fas fa-cogs"></i> Prepare
                                            </button>
                                        </form>
                                        {% endif %}
                                    {% endif %}
                                </div>
                            </td>
                        </tr>
                        {% endfor %}
                    </tbody>
                </table>
            </div>
            {% else %}
            <p class="text-muted">You haven't uploaded any master Excel files yet.</p>
            <a href="{% url 'master-excel-create' %}" class="btn btn-primary">
                <i class="fas fa-upload"></i> Upload Your First File
            </a>
            {% endif %}
        </div>
    </div>
</div>
{% endblock %}

{% block extra_js %}
<script>
async function downloadTemplateWithFetch(event) {
    event.preventDefault();

    const btn = event.currentTarget;
    const icon = btn.querySelector('#download-icon');
    const text = btn.querySelector('#download-text');
    const url = '{% url "download-master-excel-template" %}';

    // Disable button immediately (prevents double-click)
    btn.disabled = true;
    icon.className = 'fas fa-spinner fa-spin';
    text.textContent = 'Downloading...';

    // Show initial toast
    showDownloadToast('Downloading master Excel template from S3...', 'info');

    try {
        // Fetch the file (GET request doesn't need CSRF token)
        const response = await fetch(url, {
            method: 'GET',
            credentials: 'same-origin',  // Include cookies for Django auth
            redirect: 'follow'  // Follow redirects (default behavior)
        });

        // CRITICAL: Check if server redirected us (indicates error with messages.error)
        // The backend uses redirect("master-excel-list") with messages.error() for all errors
        // If redirected, we need to do a full page navigation to show Django messages
        if (response.redirected) {
            console.log('Server redirected to:', response.url);
            console.log('Following redirect to display server error messages...');
            // Do full page navigation to show Django messages properly
            window.location.href = response.url;
            return;  // Don't continue processing
        }

        // Check for HTTP errors
        if (!response.ok) {
            throw new Error(`Server error ${response.status}: ${response.statusText}`);
        }

        // CRITICAL: Verify we got an actual file, not an HTML error page
        // This handles cases where server returns 200 OK but with wrong content
        const contentType = response.headers.get('content-type');
        const contentDisposition = response.headers.get('content-disposition');

        // Expected content type for Excel files
        const validContentTypes = [
            'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',  // .xlsx
            'application/vnd.ms-excel',  // .xls
            'application/octet-stream'   // generic binary (sometimes used for downloads)
        ];

        const isValidType = validContentTypes.some(type =>
            contentType && contentType.includes(type)
        );

        if (!isValidType) {
            console.error('Invalid content type:', contentType);
            throw new Error(
                `Server returned unexpected content type: ${contentType}. ` +
                'Expected Excel file but may have received HTML error page or redirect.'
            );
        }

        // Verify Content-Disposition indicates file attachment
        if (!contentDisposition || !contentDisposition.includes('attachment')) {
            console.warn('Missing or invalid Content-Disposition:', contentDisposition);
            // This is a warning not error - some servers don't set it properly
            // but if Content-Type is correct we proceed
        }

        // Download successful - convert to blob
        const blob = await response.blob();

        // Additional safety check: Excel files should be reasonably sized (not tiny HTML error pages)
        if (blob.size < 1024) {  // Less than 1KB is suspicious for an Excel file
            console.error('File suspiciously small:', blob.size, 'bytes');
            throw new Error('Downloaded file is too small to be valid Excel template (possible error page).');
        }

        // Parse filename from Content-Disposition header (respects server-side naming)
        // This allows backend to control versioning, localization, etc.
        let filename = 'master_input_template.xlsx';  // Fallback default
        if (contentDisposition) {
            // Try RFC 5987 encoding first (filename*=UTF-8''...)
            const filenameStarMatch = contentDisposition.match(/filename\*=UTF-8''([^;]+)/i);
            if (filenameStarMatch) {
                filename = decodeURIComponent(filenameStarMatch[1]);
            } else {
                // Fall back to standard filename="..." or filename=...
                const filenameMatch = contentDisposition.match(/filename[^;=\n]*=["']?([^"';]+)["']?/i);
                if (filenameMatch) {
                    filename = filenameMatch[1].trim();
                }
            }
        }

        // Create blob URL and trigger download
        const blobUrl = window.URL.createObjectURL(blob);
        const downloadLink = document.createElement('a');
        downloadLink.href = blobUrl;
        downloadLink.download = filename;

        // Trigger download
        document.body.appendChild(downloadLink);
        downloadLink.click();
        document.body.removeChild(downloadLink);

        // Clean up blob URL
        window.URL.revokeObjectURL(blobUrl);

        // Show success feedback
        icon.className = 'fas fa-check-circle';
        text.textContent = 'Downloaded!';
        showDownloadToast('Master Excel template downloaded successfully! Check your downloads folder.', 'success');

        // Reset button after success delay
        setTimeout(() => {
            btn.disabled = false;
            icon.className = 'fas fa-download';
            text.textContent = 'Download Template';
        }, 2000);

    } catch (error) {
        // Handle all error cases
        console.error('Download error:', error);

        // Show error feedback
        icon.className = 'fas fa-exclamation-circle';
        text.textContent = 'Download Failed';

        // Determine user-friendly error message
        let errorMessage = 'Download failed. ';
        if (error.message.includes('Failed to fetch')) {
            errorMessage += 'Network error - check your internet connection.';
        } else if (error.message.includes('404')) {
            errorMessage += 'Template file not found on server.';
        } else if (error.message.includes('500')) {
            errorMessage += 'Server error - please try again later.';
        } else if (error.message.includes('content type') || error.message.includes('Content-Type')) {
            errorMessage += 'Server returned invalid file type. You may need to log in again.';
        } else if (error.message.includes('too small')) {
            errorMessage += 'Downloaded file appears corrupted or invalid.';
        } else {
            errorMessage += error.message;
        }

        showDownloadToast(errorMessage, 'danger');

        // Reset button after error delay
        setTimeout(() => {
            btn.disabled = false;
            icon.className = 'fas fa-download';
            text.textContent = 'Download Template';
        }, 3000);
    }
}
</script>
{% endblock %}