/**
 * client-assets/js/soil-import.js
 *
 * Handles the lab spreadsheet import flow on the soil test entry page.
 *
 * Flow:
 *  1. User picks a file → "Analyse File" button enabled
 *  2. File is sent to soilImportController.php?action=parse
 *  3. If one sample:  auto-import it
 *     If many samples: show a sample picker table
 *  4. User picks a sample → sent to soilImportController.php?action=import
 *  5. Mapped values are filled into the soil analysis form
 */

(function () {
    'use strict';

    // ── DOM refs ──────────────────────────────────────────────────────────────

    const fileInput      = document.getElementById('lab-file-input');
    const analyseBtn     = document.getElementById('lab-analyse-btn');
    const importStatus   = document.getElementById('import-status');
    const samplePanel    = document.getElementById('sample-picker-panel');
    const sampleTable    = document.getElementById('sample-picker-table');
    const sampleTbody    = sampleTable ? sampleTable.querySelector('tbody') : null;
    const importProgress = document.getElementById('import-progress');

    if (!fileInput || !analyseBtn) return; // not on the right page

    // ── helpers ───────────────────────────────────────────────────────────────

    function showStatus(msg, type = 'info') {
        if (!importStatus) return;
        importStatus.className = `alert alert-${type} mt-2`;
        importStatus.textContent = msg;
        importStatus.hidden = false;
    }

    function hideStatus() {
        if (importStatus) importStatus.hidden = true;
    }

    function setProgress(visible, text = '') {
        if (!importProgress) return;
        importProgress.hidden = !visible;
        if (text) importProgress.querySelector('.progress-label').textContent = text;
    }

    function buildFormData(file, action, extraFields = {}) {
        const fd = new FormData();
        fd.append('file', file);
        fd.append('action', action);
        for (const [k, v] of Object.entries(extraFields)) {
            fd.append(k, v);
        }
        return fd;
    }

    async function postToController(formData) {
        const resp = await fetch('/controllers/soilImportController.php', {
            method: 'POST',
            body: formData,
        });
        if (!resp.ok) {
            throw new Error(`Server error ${resp.status}`);
        }
        return resp.json();
    }

    // ── form population ───────────────────────────────────────────────────────

    function populateForm(fields) {
        let filled = 0;
        let skipped = 0;

        for (const [fieldName, value] of Object.entries(fields)) {
            if (value === null || value === undefined || value === '') continue;

            const el = document.getElementById(fieldName)
                    || document.querySelector(`[name="${fieldName}"]`);

            if (!el) { skipped++; continue; }

            if (el.tagName === 'SELECT') {
                // Try to find a matching option (case-insensitive)
                const val = String(value).toLowerCase();
                for (const opt of el.options) {
                    if (opt.value.toLowerCase() === val || opt.text.toLowerCase() === val) {
                        el.value = opt.value;
                        filled++;
                        break;
                    }
                }
            } else {
                el.value = value;
                el.dispatchEvent(new Event('input', { bubbles: true }));
                filled++;
            }
        }

        return { filled, skipped };
    }

    // Highlight fields that were auto-filled so the user can review them
    function highlightFilledFields(fields) {
        for (const fieldName of Object.keys(fields)) {
            if (fields[fieldName] === null || fields[fieldName] === '') continue;
            const el = document.getElementById(fieldName)
                     || document.querySelector(`[name="${fieldName}"]`);
            if (el) {
                el.classList.add('border-success', 'bg-success-subtle');
            }
        }
    }

    // ── sample picker ─────────────────────────────────────────────────────────

    function renderSamplePicker(samples, file) {
        if (!samplePanel || !sampleTbody) return;

        sampleTbody.innerHTML = '';

        samples.forEach((s) => {
            const tr = document.createElement('tr');
            tr.innerHTML = `
                <td>${escHtml(s.lab_id)}</td>
                <td>${escHtml(s.client)}</td>
                <td>${escHtml(s.site)}</td>
                <td>${escHtml(s.crop)}</td>
                <td>
                    <button class="btn btn-sm btn-success"
                            data-idx="${s.idx}"
                            type="button">
                        Import
                    </button>
                </td>`;
            sampleTbody.appendChild(tr);
        });

        // Wire import buttons
        sampleTbody.querySelectorAll('button[data-idx]').forEach((btn) => {
            btn.addEventListener('click', async () => {
                const idx = btn.dataset.idx;
                await importSample(file, idx);
            });
        });

        samplePanel.hidden = false;
        samplePanel.scrollIntoView({ behavior: 'smooth', block: 'nearest' });
    }

    function escHtml(str) {
        const d = document.createElement('div');
        d.textContent = str || '';
        return d.innerHTML;
    }

    // ── import a specific sample ──────────────────────────────────────────────

    async function importSample(file, sampleIdx) {
        setProgress(true, 'Mapping fields with AI…');
        hideStatus();

        try {
            const fd   = buildFormData(file, 'import', { sample_idx: sampleIdx });
            const data = await postToController(fd);

            if (!data.success) {
                showStatus('Import failed: ' + data.error, 'danger');
                return;
            }

            const { filled, skipped } = populateForm(data.fields);
            highlightFilledFields(data.fields);

            if (samplePanel) samplePanel.hidden = true;

            const method  = data.method === 'ai' ? 'AI-assisted' : 'pattern-matched';
            const warning = data.warning ? ` (${data.warning})` : '';
            showStatus(
                `${filled} field${filled !== 1 ? 's' : ''} populated via ${method}${warning}. ` +
                `Please review and adjust before submitting.`,
                data.warning ? 'warning' : 'success'
            );

            // Scroll to the form
            document.getElementById('SoilcsvForm')?.scrollIntoView({ behavior: 'smooth' });

        } catch (err) {
            showStatus('Error: ' + err.message, 'danger');
        } finally {
            setProgress(false);
        }
    }

    // ── main: analyse file ────────────────────────────────────────────────────

    fileInput.addEventListener('change', () => {
        analyseBtn.disabled = !fileInput.files.length;
        hideStatus();
        if (samplePanel) samplePanel.hidden = true;
    });

    analyseBtn.addEventListener('click', async () => {
        const file = fileInput.files[0];
        if (!file) return;

        setProgress(true, 'Parsing file…');
        hideStatus();
        if (samplePanel) samplePanel.hidden = true;
        analyseBtn.disabled = true;

        try {
            const fd   = buildFormData(file, 'parse');
            const data = await postToController(fd);

            if (!data.success) {
                showStatus('Parse failed: ' + data.error, 'danger');
                return;
            }

            if (data.count === 1) {
                // Single sample — go straight to import
                await importSample(file, 0);
            } else {
                showStatus(
                    `Found ${data.count} samples. Select the one you want to import.`,
                    'info'
                );
                renderSamplePicker(data.samples, file);
            }

        } catch (err) {
            showStatus('Error reading file: ' + err.message, 'danger');
        } finally {
            setProgress(false);
            analyseBtn.disabled = false;
        }
    });

})();