"""
Admin routes for backup, verify and restore.

Restores are deliberately awkward: they need an explicit typed confirmation
and, for a wipe, a second flag. The CLI (`flask backup restore`) is the
better path on a fresh Docker instance where no admin user exists yet.

Created by: Jess Rogerson (yelling commands at Claude.AI)
"""

import os

from flask import (Blueprint, render_template, redirect, url_for, flash,
                   request, jsonify, send_file, current_app, abort)
from flask_login import login_required, current_user

from app.routes.admin import admin_required
from app.services import backup_service as bsvc

backup_bp = Blueprint('backup', __name__, url_prefix='/admin/backup')


@backup_bp.route('/')
@login_required
@admin_required
def index():
    """Backup management page."""
    backups = bsvc.list_backups()
    total_bytes = sum(b['size_bytes'] for b in backups)

    uploads_root = bsvc.upload_folder()
    upload_files = list(bsvc.walk_uploads(uploads_root))
    uploads_bytes = sum(os.path.getsize(p) for p, _ in upload_files)

    expected = bsvc.referenced_files()
    on_disk = {rel for _, rel in upload_files}
    missing = sorted(expected - on_disk)
    orphaned = sorted(on_disk - expected)

    return render_template(
        'admin/backup.html',
        backups=backups,
        backup_folder=bsvc.backup_folder(),
        backup_total_human=bsvc.human_size(total_bytes),
        uploads_root=uploads_root,
        upload_file_count=len(upload_files),
        uploads_human=bsvc.human_size(uploads_bytes),
        missing=missing,
        orphaned=orphaned,
        dialect=bsvc.database_dialect(),
        sqlite_path=bsvc.sqlite_db_path(),
        keep=current_app.config.get('BACKUP_KEEP'),
    )


@backup_bp.route('/create', methods=['POST'])
@login_required
@admin_required
def create():
    """Start a backup in the background and hand back a job id."""
    label = (request.form.get('label') or '').strip() or None
    job_id = bsvc.start_backup_job(
        current_app._get_current_object(),
        created_by=current_user.username,
        label=label,
        keep=current_app.config.get('BACKUP_KEEP'),
    )
    return jsonify({'job_id': job_id})


@backup_bp.route('/status/<job_id>')
@login_required
@admin_required
def status(job_id):
    job = bsvc.get_job(job_id)
    if not job:
        return jsonify({'error': 'Unknown job'}), 404
    return jsonify(job)


@backup_bp.route('/download/<path:filename>')
@login_required
@admin_required
def download(filename):
    folder = bsvc.backup_folder()
    safe = os.path.basename(filename)
    path = os.path.join(folder, safe)
    if not os.path.isfile(path):
        abort(404)
    return send_file(path, as_attachment=True, download_name=safe)


@backup_bp.route('/verify/<path:filename>')
@login_required
@admin_required
def verify(filename):
    folder = bsvc.backup_folder()
    safe = os.path.basename(filename)
    path = os.path.join(folder, safe)
    if not os.path.isfile(path):
        return jsonify({'error': 'Not found'}), 404

    report = bsvc.verify_backup(path)
    return jsonify({
        'ok': report['ok'],
        'checked': report['checked'],
        'failed': report['failed'][:20],
        'missing': report['missing'][:20],
        'errors': report['errors'],
    })


@backup_bp.route('/delete/<path:filename>', methods=['POST'])
@login_required
@admin_required
def delete(filename):
    try:
        removed = bsvc.delete_backup(filename)
        flash(f'Deleted backup {removed}', 'success')
    except FileNotFoundError:
        flash('That backup no longer exists.', 'warning')
    except ValueError as exc:
        flash(str(exc), 'danger')
    return redirect(url_for('backup.index'))


@backup_bp.route('/restore/<path:filename>', methods=['POST'])
@login_required
@admin_required
def restore(filename):
    """Restore an archive that already sits in the backup folder."""
    folder = bsvc.backup_folder()
    safe = os.path.basename(filename)
    path = os.path.join(folder, safe)
    if not os.path.isfile(path):
        flash('That backup no longer exists.', 'warning')
        return redirect(url_for('backup.index'))

    if request.form.get('confirm', '').strip().upper() != 'RESTORE':
        flash('Restore cancelled: confirmation text did not match.', 'warning')
        return redirect(url_for('backup.index'))

    mode = request.form.get('mode', 'merge')
    force = request.form.get('force') == 'on'
    overwrite = request.form.get('overwrite_files') == 'on'

    try:
        summary = bsvc.restore_backup(path, mode=mode, force=force,
                                      overwrite_files=overwrite)
    except Exception as exc:  # noqa: BLE001 - reported to the admin
        current_app.logger.exception('Restore failed')
        flash(f'Restore failed: {exc}', 'danger')
        return redirect(url_for('backup.index'))

    inserted = ', '.join(f"{v} {k}" for k, v in summary['inserted'].items() if v)
    flash(
        f"Restore complete ({mode} mode). Rows added: {inserted or 'none'}. "
        f"Files written: {summary['files_written']} "
        f"({summary['files_bytes_human']}), skipped: {summary['files_skipped']}.",
        'success'
    )
    for warning in summary['warnings']:
        flash(warning, 'info')
    return redirect(url_for('backup.index'))