(function() {
    const fileInput = document.getElementById('import-file');
    const previewEl = document.getElementById('csv-preview');
    const previewTable = document.getElementById('preview-table');
    const mappingEl = document.getElementById('column-mapping');
    const startBtn = document.getElementById('start-import-btn');
    const progressEl = document.getElementById('import-progress');
    const resultEl = document.getElementById('import-result');

    const csrfToken = document.getElementById('dashboard-import-inline-cfg').dataset.csrfToken;

    let csvBase64 = '';
    let csvHeaders = [];

    fileInput.addEventListener('change', function(e) {
        const file = e.target.files[0];
        if (!file) return;

        const reader = new FileReader();
        reader.onload = function(ev) {
            const text = ev.target.result;
            csvBase64 = btoa(unescape(encodeURIComponent(text)));

            const lines = text.split('\n').filter(l => l.trim());
            if (lines.length < 2) {
                alert('CSV must have a header row and at least one data row.');
                return;
            }

            csvHeaders = parseCSVLine(lines[0]);

            // Build preview table
            let html = '<thead><tr>';
            csvHeaders.forEach(h => { html += '<th>' + escapeHtml(h) + '</th>'; });
            html += '</tr></thead><tbody>';
            for (let i = 1; i < Math.min(lines.length, 4); i++) {
                const cols = parseCSVLine(lines[i]);
                html += '<tr>';
                csvHeaders.forEach((_, ci) => {
                    html += '<td>' + escapeHtml(cols[ci] || '') + '</td>';
                });
                html += '</tr>';
            }
            html += '</tbody>';
            previewTable.innerHTML = html;
            previewEl.classList.remove('hidden');

            // Populate mapping selects
            const selects = mappingEl.querySelectorAll('select');
            selects.forEach(sel => {
                const current = sel.value;
                sel.innerHTML = '<option value="">-- skip --</option>';
                csvHeaders.forEach((h, i) => {
                    const opt = document.createElement('option');
                    opt.value = i;
                    opt.textContent = h;
                    sel.appendChild(opt);
                });
                // Auto-detect common column names
                autoDetectColumn(sel, csvHeaders);
            });
            mappingEl.classList.remove('hidden');
        };
        reader.readAsText(file);
    });

    function autoDetectColumn(select, headers) {
        const id = select.id;
        const lower = headers.map(h => h.toLowerCase().trim());
        const patterns = {
            'map-email': ['email', 'e-mail', 'email_address', 'subscriber_email'],
            'map-name': ['name', 'full_name', 'display_name', 'subscriber_name'],
            'map-amount': ['amount', 'total', 'price', 'payment', 'lifetime_amount'],
            'map-date': ['date', 'created_at', 'joined', 'start_date', 'signup_date'],
            'map-item-title': ['item', 'product', 'title', 'item_title', 'product_name'],
            'map-tier': ['tier', 'plan', 'level', 'membership'],
            'map-status': ['status', 'state', 'active']
        };
        const p = patterns[id] || [];
        for (let i = 0; i < lower.length; i++) {
            if (p.includes(lower[i])) {
                select.value = i;
                return;
            }
        }
    }

    startBtn.addEventListener('click', function() {
        const projectId = document.getElementById('import-project').value;
        if (!csvBase64) {
            alert('Please select a CSV file first.');
            return;
        }

        const mapping = {};
        const mapEmail = document.getElementById('map-email').value;
        const mapName = document.getElementById('map-name').value;
        const mapAmount = document.getElementById('map-amount').value;
        const mapDate = document.getElementById('map-date').value;
        const mapItem = document.getElementById('map-item-title').value;
        const mapTier = document.getElementById('map-tier').value;
        const mapStatus = document.getElementById('map-status').value;

        if (mapEmail) mapping.email = parseInt(mapEmail);
        if (mapName) mapping.name = parseInt(mapName);
        if (mapAmount) mapping.amount = parseInt(mapAmount);
        if (mapDate) mapping.date = parseInt(mapDate);
        if (mapItem) mapping.item_title = parseInt(mapItem);
        if (mapTier) mapping.tier = parseInt(mapTier);
        if (mapStatus) mapping.status = parseInt(mapStatus);

        if (!mapping.email && !mapping.amount) {
            alert('Please map at least an email or amount column.');
            return;
        }

        startBtn.disabled = true;
        startBtn.textContent = 'Starting...';

        fetch('/api/users/me/import', {
            method: 'POST',
            headers: {
                'Content-Type': 'application/json',
                'X-CSRF-Token': csrfToken
            },
            body: JSON.stringify({
                project_id: projectId,
                source: 'generic_csv',
                csv_data: csvBase64,
                column_mapping: mapping
            })
        })
        .then(r => r.json())
        .then(data => {
            if (data.error) {
                resultEl.className = 'import-result error';
                resultEl.textContent = data.error;
                startBtn.disabled = false;
                startBtn.textContent = 'Start Import';
                return;
            }
            progressEl.classList.remove('hidden');
            pollProgress(data.job_id);
        })
        .catch(err => {
            resultEl.className = 'import-result error';
            resultEl.textContent = 'Failed to start import: ' + err.message;
            startBtn.disabled = false;
            startBtn.textContent = 'Start Import';
        });
    });

    function pollProgress(jobId) {
        const interval = setInterval(() => {
            fetch('/api/users/me/import/' + jobId)
                .then(r => r.json())
                .then(data => {
                    const pct = data.total_rows > 0
                        ? Math.round((data.processed_rows / data.total_rows) * 100)
                        : 0;
                    document.getElementById('progress-bar').style.width = pct + '%';
                    document.getElementById('stat-processed').textContent = data.processed_rows;
                    document.getElementById('stat-created').textContent = data.created_rows;
                    document.getElementById('stat-skipped').textContent = data.skipped_rows;

                    if (data.status === 'completed' || data.status === 'failed') {
                        clearInterval(interval);
                        progressEl.classList.add('hidden');

                        resultEl.classList.remove('hidden');
                        if (data.status === 'completed') {
                            resultEl.className = 'import-result success';
                            resultEl.innerHTML = '<strong>Import complete.</strong> ' +
                                data.created_rows + ' created, ' +
                                data.skipped_rows + ' skipped.';
                        } else {
                            resultEl.className = 'import-result error';
                            resultEl.innerHTML = '<strong>Import failed.</strong>';
                        }
                        if (data.error_log) {
                            resultEl.innerHTML += '<div class="error-log">' +
                                escapeHtml(data.error_log) + '</div>';
                        }
                        startBtn.disabled = false;
                        startBtn.textContent = 'Start Import';
                    }
                });
        }, 2000);
    }

    function parseCSVLine(line) {
        const result = [];
        let current = '';
        let inQuotes = false;
        for (let i = 0; i < line.length; i++) {
            const ch = line[i];
            if (inQuotes) {
                if (ch === '"' && line[i+1] === '"') { current += '"'; i++; }
                else if (ch === '"') { inQuotes = false; }
                else { current += ch; }
            } else {
                if (ch === '"') { inQuotes = true; }
                else if (ch === ',') { result.push(current.trim()); current = ''; }
                else { current += ch; }
            }
        }
        result.push(current.trim());
        return result;
    }

})();