/**
 * Settings — backup / restore configuration.
 */

import { apiKey } from '../core/state.js';
import { API_BASE, fetchWithAuth } from '../core/api.js';
import { Modal } from '../core/modal.js';
import { showToast, showConfirm } from '../core/ui.js';
import { t } from '../core/i18n.js';
import { ICON_UNDO, ICON_DOWNLOAD } from '../core/icons.js';

// Simple modal (no form / no dirty check needed)
const settingsModal = new Modal('settings-modal');

export function openSettingsModal() {
    document.getElementById('settings-error').style.display = 'none';
    settingsModal.open();
    loadAutoBackupSettings();
    loadBackupList();
}

export function closeSettingsModal() {
    settingsModal.forceClose();
}

// ─── Backup ────────────────────────────────────────────────

export async function downloadBackup() {
    try {
        const resp = await fetchWithAuth('/system/backup', { timeout: 30000 });
        if (!resp.ok) {
            const err = await resp.json().catch(() => ({}));
            throw new Error(err.detail || `HTTP ${resp.status}`);
        }
        const blob = await resp.blob();
        const disposition = resp.headers.get('Content-Disposition') || '';
        const match = disposition.match(/filename="(.+?)"/);
        const filename = match ? match[1] : 'ledgrab-backup.json';

        const a = document.createElement('a');
        a.href = URL.createObjectURL(blob);
        a.download = filename;
        document.body.appendChild(a);
        a.click();
        a.remove();
        URL.revokeObjectURL(a.href);

        showToast(t('settings.backup.success'), 'success');
    } catch (err) {
        console.error('Backup download failed:', err);
        showToast(t('settings.backup.error') + ': ' + err.message, 'error');
    }
}

// ─── Restore ───────────────────────────────────────────────

export async function handleRestoreFileSelected(input) {
    const file = input.files[0];
    input.value = '';
    if (!file) return;

    const confirmed = await showConfirm(t('settings.restore.confirm'));
    if (!confirmed) return;

    try {
        const formData = new FormData();
        formData.append('file', file);

        const resp = await fetch(`${API_BASE}/system/restore`, {
            method: 'POST',
            headers: { 'Authorization': `Bearer ${apiKey}` },
            body: formData,
        });

        if (!resp.ok) {
            const err = await resp.json().catch(() => ({}));
            throw new Error(err.detail || `HTTP ${resp.status}`);
        }

        const data = await resp.json();
        showToast(data.message || t('settings.restore.success'), 'success');
        settingsModal.forceClose();

        if (data.restart_scheduled) {
            showRestartOverlay();
        }
    } catch (err) {
        console.error('Restore failed:', err);
        showToast(t('settings.restore.error') + ': ' + err.message, 'error');
    }
}

// ─── Restart overlay ───────────────────────────────────────

function showRestartOverlay() {
    const overlay = document.createElement('div');
    overlay.id = 'restart-overlay';
    overlay.style.cssText =
        'position:fixed;inset:0;z-index:100000;display:flex;flex-direction:column;' +
        'align-items:center;justify-content:center;background:rgba(0,0,0,0.85);color:#fff;font-size:1.2rem;';
    overlay.innerHTML =
        '<div class="spinner" style="width:48px;height:48px;border:4px solid rgba(255,255,255,0.3);' +
        'border-top-color:#fff;border-radius:50%;animation:spin 0.8s linear infinite;margin-bottom:1rem;"></div>' +
        `<div id="restart-msg">${t('settings.restore.restarting')}</div>`;

    // Add spinner animation if not present
    if (!document.getElementById('restart-spinner-style')) {
        const style = document.createElement('style');
        style.id = 'restart-spinner-style';
        style.textContent = '@keyframes spin{to{transform:rotate(360deg)}}';
        document.head.appendChild(style);
    }

    document.body.appendChild(overlay);
    pollHealth();
}

function pollHealth() {
    const start = Date.now();
    const maxWait = 30000;
    const interval = 1500;

    const check = async () => {
        if (Date.now() - start > maxWait) {
            const msg = document.getElementById('restart-msg');
            if (msg) msg.textContent = t('settings.restore.restart_timeout');
            return;
        }
        try {
            const resp = await fetch('/health', { signal: AbortSignal.timeout(3000) });
            if (resp.ok) {
                window.location.reload();
                return;
            }
        } catch { /* server still down */ }
        setTimeout(check, interval);
    };
    // Wait a moment before first check to let the server shut down
    setTimeout(check, 2000);
}

// ─── Auto-Backup settings ─────────────────────────────────

export async function loadAutoBackupSettings() {
    try {
        const resp = await fetchWithAuth('/system/auto-backup/settings');
        if (!resp.ok) return;
        const data = await resp.json();

        document.getElementById('auto-backup-enabled').checked = data.enabled;
        document.getElementById('auto-backup-interval').value = String(data.interval_hours);
        document.getElementById('auto-backup-max').value = data.max_backups;

        const statusEl = document.getElementById('auto-backup-status');
        if (data.last_backup_time) {
            const d = new Date(data.last_backup_time);
            statusEl.textContent = t('settings.auto_backup.last_backup') + ': ' + d.toLocaleString();
        } else {
            statusEl.textContent = t('settings.auto_backup.last_backup') + ': ' + t('settings.auto_backup.never');
        }
    } catch (err) {
        console.error('Failed to load auto-backup settings:', err);
    }
}

export async function saveAutoBackupSettings() {
    const enabled = document.getElementById('auto-backup-enabled').checked;
    const interval_hours = parseFloat(document.getElementById('auto-backup-interval').value);
    const max_backups = parseInt(document.getElementById('auto-backup-max').value, 10);

    try {
        const resp = await fetchWithAuth('/system/auto-backup/settings', {
            method: 'PUT',
            body: JSON.stringify({ enabled, interval_hours, max_backups }),
        });
        if (!resp.ok) {
            const err = await resp.json().catch(() => ({}));
            throw new Error(err.detail || `HTTP ${resp.status}`);
        }
        showToast(t('settings.auto_backup.saved'), 'success');
        loadAutoBackupSettings();
        loadBackupList();
    } catch (err) {
        console.error('Failed to save auto-backup settings:', err);
        showToast(t('settings.auto_backup.save_error') + ': ' + err.message, 'error');
    }
}

// ─── Saved backup list ────────────────────────────────────

export async function loadBackupList() {
    const container = document.getElementById('saved-backups-list');
    try {
        const resp = await fetchWithAuth('/system/backups');
        if (!resp.ok) return;
        const data = await resp.json();

        if (data.count === 0) {
            container.innerHTML = `<div style="color:var(--text-muted);font-size:0.85rem;">${t('settings.saved_backups.empty')}</div>`;
            return;
        }

        container.innerHTML = data.backups.map(b => {
            const sizeKB = (b.size_bytes / 1024).toFixed(1);
            const date = new Date(b.created_at).toLocaleString();
            return `<div style="display:flex;align-items:center;gap:0.5rem;padding:0.3rem 0;border-bottom:1px solid var(--border-color);font-size:0.82rem;">
                <div style="flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;" title="${b.filename}">
                    <span>${date}</span>
                    <span style="color:var(--text-muted);margin-left:0.3rem;">${sizeKB} KB</span>
                </div>
                <button class="btn btn-icon btn-secondary" onclick="restoreSavedBackup('${b.filename}')" title="${t('settings.saved_backups.restore')}" style="padding:2px 6px;font-size:0.8rem;">${ICON_UNDO}</button>
                <button class="btn btn-icon btn-secondary" onclick="downloadSavedBackup('${b.filename}')" title="${t('settings.saved_backups.download')}" style="padding:2px 6px;font-size:0.8rem;">${ICON_DOWNLOAD}</button>
                <button class="btn btn-icon btn-secondary" onclick="deleteSavedBackup('${b.filename}')" title="${t('settings.saved_backups.delete')}" style="padding:2px 6px;font-size:0.8rem;">&#x2715;</button>
            </div>`;
        }).join('');
    } catch (err) {
        console.error('Failed to load backup list:', err);
        container.innerHTML = '';
    }
}

export async function downloadSavedBackup(filename) {
    try {
        const resp = await fetchWithAuth(`/system/backups/${encodeURIComponent(filename)}`, { timeout: 30000 });
        if (!resp.ok) {
            const err = await resp.json().catch(() => ({}));
            throw new Error(err.detail || `HTTP ${resp.status}`);
        }
        const blob = await resp.blob();
        const a = document.createElement('a');
        a.href = URL.createObjectURL(blob);
        a.download = filename;
        document.body.appendChild(a);
        a.click();
        a.remove();
        URL.revokeObjectURL(a.href);
    } catch (err) {
        console.error('Backup download failed:', err);
        showToast(t('settings.backup.error') + ': ' + err.message, 'error');
    }
}

export async function restoreSavedBackup(filename) {
    const confirmed = await showConfirm(t('settings.restore.confirm'));
    if (!confirmed) return;

    try {
        // Download the backup file from the server
        const dlResp = await fetchWithAuth(`/system/backups/${encodeURIComponent(filename)}`, { timeout: 30000 });
        if (!dlResp.ok) {
            const err = await dlResp.json().catch(() => ({}));
            throw new Error(err.detail || `HTTP ${dlResp.status}`);
        }
        const blob = await dlResp.blob();

        // POST it to the restore endpoint
        const formData = new FormData();
        formData.append('file', blob, filename);

        const resp = await fetch(`${API_BASE}/system/restore`, {
            method: 'POST',
            headers: { 'Authorization': `Bearer ${apiKey}` },
            body: formData,
        });

        if (!resp.ok) {
            const err = await resp.json().catch(() => ({}));
            throw new Error(err.detail || `HTTP ${resp.status}`);
        }

        const data = await resp.json();
        showToast(data.message || t('settings.restore.success'), 'success');
        settingsModal.forceClose();

        if (data.restart_scheduled) {
            showRestartOverlay();
        }
    } catch (err) {
        console.error('Restore from saved backup failed:', err);
        showToast(t('settings.restore.error') + ': ' + err.message, 'error');
    }
}

export async function deleteSavedBackup(filename) {
    const confirmed = await showConfirm(t('settings.saved_backups.delete_confirm'));
    if (!confirmed) return;

    try {
        const resp = await fetchWithAuth(`/system/backups/${encodeURIComponent(filename)}`, {
            method: 'DELETE',
        });
        if (!resp.ok) {
            const err = await resp.json().catch(() => ({}));
            throw new Error(err.detail || `HTTP ${resp.status}`);
        }
        loadBackupList();
    } catch (err) {
        console.error('Backup delete failed:', err);
        showToast(t('settings.saved_backups.delete_error') + ': ' + err.message, 'error');
    }
}