import { apiGet } from '../api.js';
import { showToast } from '../app.js';

let coachesList = [];
let expandedCoachId = null;
let recentByCoach = {};
let filterSearch = '';

export async function coachesPage() {
    const app = document.getElementById('app');
    app.innerHTML = `
        <div class="page-header">
            <h1>Coach activity</h1>
            <div class="actions"><a href="#/" class="btn">&larr; Dashboard</a></div>
        </div>
        <div id="coachesContent"><div class="spinner"></div></div>
    `;

    try {
        const data = await apiGet('coaches.php');
        coachesList = data.coaches || [];
        renderCoaches();
    } catch (e) {
        showToast(e.message, 'error');
        document.getElementById('coachesContent').innerHTML =
            `<p class="error-text">${esc(e.message)}</p>`;
    }
}

function coachSearchText(c) {
    return [c.username, c.coachID, c.supervisorUsername].filter(Boolean).join(' ');
}

function coachHasUploads(c) {
    return (c.totalSubmissions ?? 0) > 0;
}

function filteredCoaches() {
    const q = filterSearch.trim().toLowerCase();
    if (!q) return coachesList;
    return coachesList.filter(c => coachSearchText(c).toLowerCase().includes(q));
}

function renderCoaches() {
    const el = document.getElementById('coachesContent');

    if (!coachesList.length) {
        el.innerHTML = `<div class="card empty-state"><h3>No coaches</h3></div>`;
        return;
    }

    el.innerHTML = `
        <div class="card">
            <p class="data-toolbar-hint" style="margin:0 0 12px">Track uploads and client load per coach. Expand a row for recent submissions.</p>
            <div class="filter-bar">
                <input type="search" id="coachListSearch" class="filter-search"
                    placeholder="Search coach or supervisor…" value="${esc(filterSearch)}">
                <span class="data-toolbar-hint" id="coachListCount"></span>
            </div>
            <div class="table-wrapper">
                <table class="data-table">
                    <thead>
                        <tr>
                            <th>Coach</th><th>Supervisor</th><th>Clients</th>
                            <th>Total uploads</th><th>7d</th><th>30d</th><th>Last upload</th>
                        </tr>
                    </thead>
                    <tbody id="coachTableBody"></tbody>
                </table>
            </div>
        </div>
    `;

    document.getElementById('coachListSearch').addEventListener('input', (e) => {
        filterSearch = e.target.value;
        const filtered = filteredCoaches();
        if (
            expandedCoachId &&
            !filtered.some(c => c.coachID === expandedCoachId && coachHasUploads(c))
        ) {
            expandedCoachId = null;
        }
        renderCoachTableBody();
    });

    renderCoachTableBody();
}

function coachRowHTML(c) {
    const canExpand = coachHasUploads(c);
    const expanded = canExpand && expandedCoachId === c.coachID;
    const recent = recentByCoach[c.coachID] || [];
    const expandControl = canExpand
        ? `<button type="button" class="btn btn-sm btn-link coach-expand-btn" data-coach="${esc(c.coachID)}">${expanded ? '▼' : '▶'}</button> `
        : '';
    return `
        <tr class="coach-row" data-coach="${esc(c.coachID)}">
            <td>${expandControl}<strong>${esc(c.username)}</strong></td>
            <td>${esc(c.supervisorUsername || '—')}</td>
            <td>${c.clientCount ?? 0}</td>
            <td>${c.totalSubmissions ?? 0}</td>
            <td>${c.submissionsLast7d ?? 0}</td>
            <td>${c.submissionsLast30d ?? 0}</td>
            <td>${esc(c.lastSubmissionAt || '—')}</td>
        </tr>
        ${expanded ? `
        <tr class="coach-detail-row">
            <td colspan="7">
                <div class="coach-recent-panel">
                    ${recent.length ? `
                    <table class="data-table data-table-compact">
                        <thead>
                            <tr><th>When</th><th>Client</th><th>Questionnaire</th><th>Ver.</th></tr>
                        </thead>
                        <tbody>
                            ${recent.map(s => `
                                <tr>
                                    <td>${esc(s.submittedAt)}</td>
                                    <td><code>${esc(s.clientCode)}</code></td>
                                    <td>${esc(s.questionnaireName)}</td>
                                    <td>${s.version}</td>
                                </tr>
                            `).join('')}
                        </tbody>
                    </table>
                    ` : '<p class="data-toolbar-hint">Loading…</p>'}
                </div>
            </td>
        </tr>` : ''}`;
}

function renderCoachTableBody() {
    const body = document.getElementById('coachTableBody');
    const countEl = document.getElementById('coachListCount');
    if (!body) return;

    const filtered = filteredCoaches();

    if (!filtered.length) {
        body.innerHTML = `
            <tr>
                <td colspan="7" style="text-align:center;color:var(--text-secondary);padding:24px">
                    No coaches match
                </td>
            </tr>`;
        if (countEl) {
            countEl.textContent = filterSearch.trim()
                ? `0 of ${coachesList.length} coaches`
                : '';
        }
        return;
    }

    body.innerHTML = filtered.map(c => coachRowHTML(c)).join('');

    if (countEl) {
        const q = filterSearch.trim();
        countEl.textContent = q
            ? `${filtered.length} of ${coachesList.length} coaches`
            : `${coachesList.length} coach${coachesList.length === 1 ? '' : 'es'}`;
    }

    body.querySelectorAll('.coach-expand-btn').forEach(btn => {
        btn.addEventListener('click', () => toggleCoach(btn.dataset.coach));
    });
}

async function toggleCoach(coachID) {
    const coach = coachesList.find(c => c.coachID === coachID);
    if (!coach || !coachHasUploads(coach)) {
        return;
    }
    if (expandedCoachId === coachID) {
        expandedCoachId = null;
        renderCoachTableBody();
        return;
    }
    expandedCoachId = coachID;
    renderCoachTableBody();
    if (!recentByCoach[coachID]) {
        try {
            const data = await apiGet(
                `coaches.php?coachID=${encodeURIComponent(coachID)}&recent=1`
            );
            recentByCoach[coachID] = data.submissions || [];
        } catch (e) {
            showToast(e.message, 'error');
            recentByCoach[coachID] = [];
        }
        renderCoachTableBody();
    }
}

function esc(s) {
    const d = document.createElement('div');
    d.textContent = s ?? '';
    return d.innerHTML;
}