/**
 * TPU Survey - Public Survey Response Logic
 * รองรับ Section -> Heading -> Question
 */

let currentSurvey = null;

async function initSurvey() {
    const params = new URLSearchParams(window.location.search);
    const link = params.get('link');
    
    if (!link) {
        showError('ไม่พบลิงก์แบบสอบถาม');
        return;
    }

    try {
        const basePath = window.location.pathname.includes('/survey') ? '/survey' : '';
        const data = await fetch(`${basePath}/api/surveys.php?action=getByLink&link=${encodeURIComponent(link)}`).then(r => r.json());
        
        if (data.error) {
            showError(data.error);
            return;
        }

        currentSurvey = data.survey;
        renderSurvey();
    } catch (err) {
        showError('ไม่สามารถโหลดแบบสอบถามได้');
    }
}

function showError(msg) {
    document.getElementById('surveyContent').innerHTML = `
        <div class="empty-state" style="padding:80px 20px;">
            <div class="empty-icon">😔</div>
            <h3>${msg}</h3>
            <p class="text-muted mt-8">ลิงก์อาจไม่ถูกต้องหรือแบบสอบถามถูกปิดแล้ว</p>
        </div>
    `;
}

function renderSurvey() {
    const container = document.getElementById('surveyContent');
    
    let html = `
        <div class="survey-header" style="text-align:center;">
            <img src="pic/logo.png" alt="TPU Logo" style="display: block; margin-left: auto; margin-right: auto; margin-bottom: 16px; height: 80px; width: auto;">
            <h1>${escapeHtml(currentSurvey.title)}</h1>
            ${currentSurvey.description ? `<p>${escapeHtml(currentSurvey.description)}</p>` : ''}
        </div>
        <form id="surveyResponseForm" onsubmit="submitSurveyResponse(event)">
            ${currentSurvey.has_certificate == 1 ? `
            <!-- ส่วนข้อมูลสำหรับรับเกียรติบัตร -->
            <div class="survey-section" style="border-top: 4px solid var(--primary-color, #2563eb);">
                <div class="survey-section-header">
                    <h2 style="font-size:1.2rem; font-weight:700; color:#1e3a8a;">🎓 ข้อมูลสำหรับรับเกียรติบัตร (ข้อมูลจำเป็น)</h2>
                    <p style="color: #4b5563; font-size:0.9rem; margin-top:4px;">กรุณาระบุชื่อ-นามสกุลจริง และอีเมลมหาวิทยาลัยตาปี หรือ Gmail เพื่อระบบจะทำการส่งไฟล์เกียรติบัตรผ่านทางอีเมลโดยอัตโนมัติ</p>
                </div>
                
                <div class="survey-question" style="margin-top:16px;">
                    <div class="q-label" style="font-weight:700;">
                        <span>ชื่อ-นามสกุลจริง (ภาษาไทย เช่น นายสมชาย ใจดี)</span>
                        <span class="required">*</span>
                    </div>
                    <input type="text" class="form-input" id="respondentName" placeholder="กรอกชื่อ-นามสกุลจริง เช่น นายสมชาย ใจดี" required style="width: 100%; max-width: 500px; margin-top: 8px;">
                </div>
                
                <div class="survey-question" style="margin-top:16px;">
                    <div class="q-label" style="font-weight:700;">
                        <span>อีเมลสำหรับรับเกียรติบัตร (มหาวิทยาลัยตาปี หรือ Gmail)</span>
                        <span class="required">*</span>
                    </div>
                    <input type="email" class="form-input" id="respondentEmail" placeholder="เช่น name@gmail.com หรือ 651234567@student.tapee.ac.th" required 
                           pattern="[a-zA-Z0-9._%+-]+@((student\\.)?tapee\\.ac\\.th|gmail\\.com|gmil\\.com)" 
                           title="กรุณาใช้อีเมลมหาวิทยาลัยตาปี หรือ Gmail เท่านั้น"
                           style="width: 100%; max-width: 500px; margin-top: 8px;">
                </div>
            </div>
            ` : ''}
    `;



    (currentSurvey.sections || []).forEach(section => {
        html += `
            <div class="survey-section">
                <div class="survey-section-header">
                    <h2>${escapeHtml(section.title)}</h2>
                    ${section.description ? `<p>${escapeHtml(section.description)}</p>` : ''}
                </div>
        `;

        // Render headings and their questions
        (section.headings || []).forEach(heading => {
            html += `
                <div class="survey-heading" style="margin:24px 0 16px; padding:16px 20px; background:linear-gradient(135deg, rgba(37,99,235,0.06), rgba(37,99,235,0.10)); border-left:4px solid var(--primary-color, #2563eb); border-radius:0 12px 12px 0;">
                    <h3 style="margin:0; font-size:1.1rem; font-weight:700; color:#1e3a8a;">📑 ${escapeHtml(heading.title)}</h3>
                    ${heading.description ? `<p style="margin:4px 0 0; font-size:0.9rem; color:#475569;">${escapeHtml(heading.description)}</p>` : ''}
                </div>
            `;

            (heading.questions || []).forEach(q => {
                html += renderQuestion(q);
            });
        });

        // Render loose questions (not in any heading)
        (section.questions || []).forEach(q => {
            html += renderQuestion(q);
        });
        html += `</div>`;
    });

    html += `
            <div class="text-center mt-32">
                <button type="submit" id="submitBtn" class="btn btn-primary btn-lg" style="min-width:200px;">
                    📤 ส่งแบบสอบถาม
                </button>
            </div>
        </form>
    `;

    container.innerHTML = html;
}

function renderQuestion(q) {
    let html = `
        <div class="survey-question">
            <div class="q-label">
                <span>${escapeHtml(q.question_text)}</span>
                ${q.is_required ? '<span class="required">*</span>' : ''}
            </div>
    `;

    if (q.description) {
        html += `<p style="font-size:0.85rem; color:#000000; margin:-4px 0 10px 0;">${escapeHtml(q.description)}</p>`;
    }

    if (q.question_type === 'radio') {
        if (q.options && q.options.length > 0) {
            html += `<div class="form-radio-group" style="flex-direction:column; align-items:flex-start;">`;
            q.options.forEach(opt => {
                html += `
                    <label class="radio-option" style="width:100%; border:none; padding:8px 0;">
                        <input type="radio" name="q_${q.id}" value="${escapeHtml(opt)}" ${q.is_required ? 'required' : ''}>
                        <span>${escapeHtml(opt)}</span>
                    </label>
                `;
            });
            html += `</div>`;
        } else {
            html += `<div class="rating-scale">`;
            const labels = ['น้อยที่สุด', 'น้อย', 'ปานกลาง', 'มาก', 'มากที่สุด'];
            for (let i = 1; i <= 5; i++) {
                html += `
                    <label>
                        <input type="radio" name="q_${q.id}" value="${i}" ${q.is_required ? 'required' : ''}>
                        <span class="rating-number">${i}</span>
                        <span class="rating-label">${labels[i-1]}</span>
                    </label>
                `;
            }
            html += `</div>`;
        }
    } else if (q.question_type === 'text') {
        html += `<textarea class="form-input" name="q_${q.id}" placeholder="กรอกความคิดเห็น..." rows="3" ${q.is_required ? 'required' : ''}></textarea>`;
    } else if (q.question_type === 'dropdown') {
        const options = q.options || [];
        html += `<select class="form-input" name="q_${q.id}" ${q.is_required ? 'required' : ''}>`;
        html += `<option value="">-- กรุณาเลือก --</option>`;
        options.forEach(opt => {
            const val = typeof opt === 'object' ? opt.value : opt;
            const label = typeof opt === 'object' ? opt.label : opt;
            html += `<option value="${escapeHtml(val)}">${escapeHtml(label)}</option>`;
        });
        html += `</select>`;
    } else if (q.question_type === 'checkbox') {
        const options = q.options || [];
        html += `<div class="form-checkbox-group">`;
        options.forEach((opt, oi) => {
            const val = typeof opt === 'object' ? opt.value : opt;
            const label = typeof opt === 'object' ? opt.label : opt;
            html += `
                <label class="checkbox-option">
                    <input type="checkbox" name="q_${q.id}_${oi}" value="${escapeHtml(val)}">
                    <span>${escapeHtml(label)}</span>
                </label>
            `;
        });
        html += `</div>`;
    }

    html += `</div>`;
    return html;
}

// Collect all questions flat for submission
function getAllQuestions() {
    const questions = [];
    (currentSurvey.sections || []).forEach(section => {
        (section.headings || []).forEach(heading => {
            (heading.questions || []).forEach(q => questions.push(q));
        });
        (section.questions || []).forEach(q => questions.push(q));
    });
    return questions;
}

async function submitSurveyResponse(e) {
    e.preventDefault();
    
    const btn = document.getElementById('submitBtn');
    btn.disabled = true;
    btn.textContent = 'กำลังส่ง...';

    const form = document.getElementById('surveyResponseForm');
    const answers = [];
    const allQuestions = getAllQuestions();

    allQuestions.forEach(q => {
        if (q.question_type === 'checkbox') {
            const values = [];
            form.querySelectorAll(`[name^="q_${q.id}_"]`).forEach(cb => {
                if (cb.checked) values.push(cb.value);
            });
            answers.push({ question_id: q.id, value: values.join(', ') });
        } else {
            const el = form.querySelector(`[name="q_${q.id}"]`);
            if (el) {
                if (el.type === 'radio') {
                    const checked = form.querySelector(`[name="q_${q.id}"]:checked`);
                    answers.push({ question_id: q.id, value: checked ? checked.value : '' });
                } else {
                    answers.push({ question_id: q.id, value: el.value });
                }
            }
        }
    });

    // Get respondent information
    const nameEl = document.getElementById('respondentName');
    const emailEl = document.getElementById('respondentEmail');
    const respondentName = nameEl ? nameEl.value.trim() : '';
    const respondentEmail = emailEl ? emailEl.value.trim() : '';

    const params = new URLSearchParams(window.location.search);

    try {
        const basePath = window.location.pathname.includes('/survey') ? '/survey' : '';
        const res = await fetch(`${basePath}/api/responses.php?action=submit`, {
            method: 'POST',
            headers: { 'Content-Type': 'application/json' },
            body: JSON.stringify({
                survey_link: params.get('link'),
                answers: answers,
                respondent_info: {
                    name: respondentName,
                    email: respondentEmail
                }
            })
        });
        const data = await res.json();

        if (data.success) {
            document.getElementById('surveyContent').innerHTML = `
                <div class="success-page" style="min-height:auto;padding:60px 20px;">
                    <div style="text-align:center;">
                        <img src="pic/logo.png" alt="TPU Logo" style="display: block; margin-left: auto; margin-right: auto; margin-bottom: 24px; height: 80px; width: auto;">
                        <div class="success-icon">✓</div>
                        <h2 style="font-size:24px;margin-bottom:12px;">ส่งแบบสอบถามสำเร็จ!</h2>
                        <p class="text-muted">ขอบคุณที่สละเวลาตอบแบบสอบถาม</p>
                    </div>
                </div>
            `;
        } else {
            throw new Error(data.error || 'เกิดข้อผิดพลาด');
        }
    } catch (err) {
        alert('เกิดข้อผิดพลาด: ' + err.message);
        btn.disabled = false;
        btn.textContent = '📤 ส่งแบบสอบถาม';
    }
}

function escapeHtml(text) {
    if (!text) return '';
    const div = document.createElement('div');
    div.textContent = text;
    return div.innerHTML;
}

document.addEventListener('DOMContentLoaded', initSurvey);