import { apiGet, apiPost, apiDelete } from '../api.js';
import { getRole, getUser, showToast } from '../app.js';

// Roles an admin can create; supervisors can only create coaches
const CREATEABLE_ROLES = {
    admin:      ['admin', 'supervisor', 'coach'],
    supervisor: ['coach'],
};

let usersList       = [];
let supervisorsList = [];
let callerRole      = '';

export async function usersPage() {
    callerRole = getRole();
    const app = document.getElementById('app');

    app.innerHTML = `
        <div class="page-header">
            <h1>Users</h1>
            <div class="actions">
                <button class="btn btn-primary" id="showCreateFormBtn">+ Create User</button>
            </div>
        </div>
        <div id="createUserWrapper" style="display:none"></div>
        <div id="usersContent"><div class="spinner"></div></div>
    `;

    document.getElementById('showCreateFormBtn').addEventListener('click', () => {
        const wrapper = document.getElementById('createUserWrapper');
        if (wrapper.style.display === 'none') {
            showCreateForm();
        } else {
            hideCreateForm();
        }
    });

    await loadUsers();
}

async function loadUsers() {
    try {
        const data = await apiGet('users.php');
        usersList       = data.users       || [];
        supervisorsList = data.supervisors || [];
        callerRole      = data.callerRole  || callerRole;
        renderUsers();
    } catch (e) {
        showToast(e.message, 'error');
        document.getElementById('usersContent').innerHTML =
            `<p class="error-text" style="padding:16px">${esc(e.message)}</p>`;
    }
}

// ── User table ────────────────────────────────────────────────────────────

function renderUsers() {
    const container = document.getElementById('usersContent');
    const myUsername = getUser();

    if (!usersList.length) {
        container.innerHTML = `
            <div class="card">
                <div class="empty-state">
                    <h3>No users found</h3>
                    <p>${callerRole === 'supervisor' ? 'You have no coaches yet.' : 'Create the first user above.'}</p>
                </div>
            </div>`;
        return;
    }

    // Group by role for a cleaner display
    const byRole = { admin: [], supervisor: [], coach: [] };
    usersList.forEach(u => (byRole[u.role] || (byRole.other = byRole.other || [])).push(u));

    // Which role groups to show
    const groups = callerRole === 'supervisor'
        ? [{ label: 'Coaches', key: 'coach' }]
        : [
            { label: 'Admins',      key: 'admin'      },
            { label: 'Supervisors', key: 'supervisor'  },
            { label: 'Coaches',     key: 'coach'       },
          ];

    container.innerHTML = groups.map(group => {
        const users = byRole[group.key] || [];
        if (!users.length) return '';
        return `
        <div class="card" style="margin-bottom:16px">
            <h3 style="margin-bottom:12px">${group.label} (${users.length})</h3>
            <div class="table-wrapper">
                <table class="data-table">
                    <thead>
                        <tr>
                            <th>Username</th>
                            ${group.key !== 'coach' ? '<th>Location</th>' : '<th>Supervisor</th>'}
                            <th>Password Change Required</th>
                            <th>Created</th>
                            <th>Actions</th>
                        </tr>
                    </thead>
                    <tbody>
                        ${users.map(u => userRowHTML(u, myUsername)).join('')}
                    </tbody>
                </table>
            </div>
        </div>`;
    }).join('');

    container.querySelectorAll('.delete-user-btn').forEach(btn => {
        btn.addEventListener('click', () => deleteUser(btn.dataset.id, btn.dataset.name));
    });
}

function userRowHTML(u, myUsername) {
    const isSelf   = u.username === myUsername;
    const detail   = u.role === 'coach'
        ? esc(u.supervisorUsername || '—')
        : esc(u.location || '—');
    const created  = u.createdAt
        ? new Date(parseInt(u.createdAt, 10) * 1000).toLocaleDateString()
        : '—';
    const pwBadge  = u.mustChangePassword == 1
        ? '<span class="badge badge-pending">Pending</span>'
        : '<span style="color:var(--text-secondary);font-size:.8rem">No</span>';

    const canDelete = !isSelf && (
        callerRole === 'admin' ||
        (callerRole === 'supervisor' && u.role === 'coach')
    );

    return `
        <tr>
            <td>
                <strong>${esc(u.username)}</strong>
                ${isSelf ? '<span class="badge badge-you">You</span>' : ''}
            </td>
            <td>${detail}</td>
            <td>${pwBadge}</td>
            <td>${created}</td>
            <td>
                ${canDelete
                    ? `<button class="btn btn-sm btn-danger delete-user-btn" data-id="${u.userID}" data-name="${esc(u.username)}">Delete</button>`
                    : ''}
            </td>
        </tr>`;
}

async function deleteUser(userID, username) {
    if (!confirm(`Delete user "${username}"? This cannot be undone.`)) return;
    try {
        const data = await apiDelete('users.php', { userID });
        if (data.success) {
            usersList = usersList.filter(u => u.userID !== userID);
            showToast(`User "${username}" deleted`, 'success');
            renderUsers();
        }
    } catch (e) {
        showToast(e.message, 'error');
    }
}

// ── Create user form ──────────────────────────────────────────────────────

function showCreateForm() {
    const wrapper = document.getElementById('createUserWrapper');
    const allowedRoles = CREATEABLE_ROLES[callerRole] || ['coach'];
    const isSupervisor = callerRole === 'supervisor';

    wrapper.style.display = '';
    wrapper.innerHTML = `
        <div class="inline-form-card" style="margin-bottom:20px">
            <h4>Create New User</h4>
            <div class="form-row">
                <div class="form-group" style="flex:2">
                    <label>Username</label>
                    <input type="text" id="cu_username" autocomplete="off" placeholder="Enter username">
                </div>
                <div class="form-group" style="flex:2">
                    <label>Password</label>
                    <input type="password" id="cu_password" autocomplete="new-password" placeholder="Min 6 characters">
                </div>
                <div class="form-group" style="flex:1;min-width:160px">
                    <label>Role</label>
                    ${isSupervisor
                        ? `<input type="text" value="Coach" disabled style="background:#f8fafc">`
                        : `<select id="cu_role">
                            ${allowedRoles.map(r =>
                                `<option value="${r}">${r.charAt(0).toUpperCase() + r.slice(1)}</option>`
                            ).join('')}
                           </select>`
                    }
                </div>
            </div>

            <div id="cu_location_row" class="form-group" ${isSupervisor ? 'style="display:none"' : ''}>
                <label>Location <span style="font-weight:400;color:var(--text-secondary)">(for admin/supervisor)</span></label>
                <input type="text" id="cu_location" placeholder="e.g. Stuttgart">
            </div>

            <div id="cu_supervisor_row" class="form-group" style="${isSupervisor ? '' : 'display:none'}">
                <label>Supervisor</label>
                ${isSupervisor
                    ? `<input type="text" value="You (auto-assigned)" disabled style="background:#f8fafc">`
                    : `<select id="cu_supervisor_select">
                        <option value="">— select supervisor —</option>
                        ${supervisorsList.map(s =>
                            `<option value="${s.supervisorID}">${esc(s.username)}${s.location ? ` (${esc(s.location)})` : ''}</option>`
                        ).join('')}
                       </select>`
                }
            </div>

            <label class="checkbox-label" style="margin-bottom:14px;display:inline-flex">
                <input type="checkbox" id="cu_mustchange" checked> Require password change on first login
            </label>

            <div style="display:flex;gap:8px">
                <button class="btn btn-primary btn-sm" id="cu_submit">Create User</button>
                <button class="btn btn-sm" id="cu_cancel">Cancel</button>
            </div>
            <p id="cu_error" class="error-text" style="display:none;margin-top:8px"></p>
        </div>
    `;

    document.getElementById('cu_username').focus();

    // Show/hide location vs supervisor field based on role selection (admin only)
    if (!isSupervisor) {
        document.getElementById('cu_role').addEventListener('change', (e) => {
            const r = e.target.value;
            document.getElementById('cu_location_row').style.display   = r !== 'coach' ? '' : 'none';
            document.getElementById('cu_supervisor_row').style.display = r === 'coach' ? '' : 'none';
        });
        // Set initial state based on default selection
        const initRole = document.getElementById('cu_role').value;
        document.getElementById('cu_location_row').style.display   = initRole !== 'coach' ? '' : 'none';
        document.getElementById('cu_supervisor_row').style.display = initRole === 'coach' ? '' : 'none';
    }

    document.getElementById('cu_submit').addEventListener('click', submitCreateUser);
    document.getElementById('cu_cancel').addEventListener('click', hideCreateForm);

    // Enter key on last visible field submits
    wrapper.querySelectorAll('input').forEach(inp => {
        inp.addEventListener('keydown', (e) => {
            if (e.key === 'Enter') submitCreateUser();
            if (e.key === 'Escape') hideCreateForm();
        });
    });
}

function hideCreateForm() {
    const wrapper = document.getElementById('createUserWrapper');
    if (wrapper) { wrapper.style.display = 'none'; wrapper.innerHTML = ''; }
}

async function submitCreateUser() {
    const errEl = document.getElementById('cu_error');
    errEl.style.display = 'none';

    const isSupervisor = callerRole === 'supervisor';
    const username     = document.getElementById('cu_username').value.trim();
    const password     = document.getElementById('cu_password').value;
    const role         = isSupervisor ? 'coach' : (document.getElementById('cu_role').value || 'coach');
    const mustChange   = document.getElementById('cu_mustchange').checked ? 1 : 0;

    let location     = '';
    let supervisorID = '';
    if (!isSupervisor) {
        if (role !== 'coach') {
            location = document.getElementById('cu_location').value.trim();
        } else {
            supervisorID = document.getElementById('cu_supervisor_select').value;
        }
    }

    if (!username) { showError(errEl, 'Username is required'); return; }
    if (password.length < 6) { showError(errEl, 'Password must be at least 6 characters'); return; }
    if (role === 'coach' && !isSupervisor && !supervisorID) {
        showError(errEl, 'Please select a supervisor for this coach');
        return;
    }

    const btn = document.getElementById('cu_submit');
    btn.disabled = true;
    btn.textContent = 'Creating...';

    try {
        const data = await apiPost('users.php', {
            username, password, role, location, supervisorID, mustChangePassword: mustChange,
        });
        if (!data.success) throw new Error(data.error || 'Failed to create user');

        // Add to local list and re-render
        usersList.push({
            userID:             data.userID,
            username:           data.username,
            role:               data.role,
            entityID:           data.entityID,
            location:           data.location || '',
            supervisorID:       data.supervisorID || null,
            supervisorUsername: data.supervisorUsername || null,
            mustChangePassword: data.mustChangePassword,
            createdAt:          data.createdAt,
        });
        showToast(`User "${data.username}" created`, 'success');
        hideCreateForm();
        renderUsers();
    } catch (e) {
        showError(errEl, e.message);
        btn.disabled = false;
        btn.textContent = 'Create User';
    }
}

function showError(el, msg) {
    el.textContent = msg;
    el.style.display = '';
}

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