"""
routes/legacy_attendance.py
============================
"Legacy Attendance" — same look/feel as Time Attendance (dashboard,
records list, Excel export) but sourced LIVE from the old remote MySQL
server (contract / employee / locations / records tables) instead of
Excel imports. Read-only: nothing is written to the remote server, and
nothing is copied into the local database.

Routes: /legacy-attendance, /legacy-attendance/records,
        /legacy-attendance/export
"""
from flask import Blueprint, render_template, request, redirect, flash, send_file, url_for
from datetime import datetime

from extensions import logger_handler
from logger_handler import log_user_activity
from utils.helpers import login_required
from legacy_attendance_service import (
    LegacyDbUnavailable,
    get_legacy_dashboard_stats,
    get_legacy_unique_locations,
    get_legacy_records,
    get_legacy_records_for_export,
    build_legacy_export_workbook,
)

bp = Blueprint('legacy_attendance', __name__)

# Fixed dropdown values — confirmed values stored in the legacy `records.type` column
LEGACY_RECORD_TYPES = ['CHECK IN', 'CHECK OUT']


def _filters_from_request():
    return {
        'employee_search': request.args.get('employee_search', ''),
        'location': request.args.get('location', ''),
        'record_type': request.args.get('record_type', ''),
        'start_date': request.args.get('start_date', ''),
        'end_date': request.args.get('end_date', ''),
    }


@bp.route('/legacy-attendance', endpoint='legacy_attendance_dashboard')
@login_required
@log_user_activity('legacy_attendance_view')
def legacy_attendance_dashboard():
    """Display legacy attendance dashboard with summary stats."""
    stats = {
        'total_records': 0,
        'unique_employees': 0,
        'unique_locations': 0,
        'earliest_record': None,
        'latest_record': None,
    }
    try:
        stats = get_legacy_dashboard_stats()
    except LegacyDbUnavailable as e:
        flash(str(e), 'error')
    except Exception as e:
        logger_handler.logger.error(f"Error loading legacy attendance dashboard: {e}")
        flash('Error loading legacy attendance dashboard. The legacy database may be unreachable.', 'error')

    return render_template('legacy_attendance_dashboard.html', stats=stats)


@bp.route('/legacy-attendance/records', endpoint='legacy_attendance_records')
@login_required
@log_user_activity('legacy_attendance_records_view')
def legacy_attendance_records():
    """Display legacy attendance records with filtering + pagination."""
    filters = _filters_from_request()
    page = request.args.get('page', 1, type=int)
    per_page = 50

    records = None
    unique_locations = []
    try:
        unique_locations = get_legacy_unique_locations()
        records = get_legacy_records(filters, page=page, per_page=per_page)
    except LegacyDbUnavailable as e:
        flash(str(e), 'error')
        return redirect(url_for('legacy_attendance.legacy_attendance_dashboard'))
    except Exception as e:
        logger_handler.logger.error(f"Error loading legacy attendance records: {e}")
        flash('Error loading legacy attendance records. The legacy database may be unreachable.', 'error')
        return redirect(url_for('legacy_attendance.legacy_attendance_dashboard'))

    return render_template(
        'legacy_attendance_records.html',
        records=records,
        unique_locations=unique_locations,
        record_types=LEGACY_RECORD_TYPES,
        filters=filters,
    )


@bp.route('/legacy-attendance/export', endpoint='export_legacy_attendance')
@login_required
@log_user_activity('legacy_attendance_export')
def export_legacy_attendance():
    """Export the currently filtered legacy attendance records to Excel."""
    filters = _filters_from_request()

    try:
        rows = get_legacy_records_for_export(filters)
    except LegacyDbUnavailable as e:
        flash(str(e), 'error')
        return redirect(url_for('legacy_attendance.legacy_attendance_records', **filters))
    except Exception as e:
        logger_handler.logger.error(f"Error exporting legacy attendance records: {e}")
        flash('Error generating export file. Please try again.', 'error')
        return redirect(url_for('legacy_attendance.legacy_attendance_records', **filters))

    if not rows:
        flash('No legacy records found to export.', 'warning')
        return redirect(url_for('legacy_attendance.legacy_attendance_records', **filters))

    logger_handler.logger.info(f"Exported {len(rows)} legacy attendance records")

    buffer = build_legacy_export_workbook(rows)
    filename = f"legacy_attendance_{datetime.now().strftime('%m%d%Y_%H%M%S')}.xlsx"

    return send_file(
        buffer,
        as_attachment=True,
        download_name=filename,
        mimetype='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'
    )