"""
Reports API Routes
提供待辦清單的統計報表和分析
"""

from flask import Blueprint, request, jsonify
from flask_jwt_extended import jwt_required, get_jwt_identity
from datetime import datetime, date, timedelta
from sqlalchemy import func, and_, or_
from models import (
    db, TodoItem, TodoItemResponsible, TodoItemFollower,
    TodoAuditLog, TodoUserPref
)
from utils.logger import get_logger
import calendar

reports_bp = Blueprint('reports', __name__)
logger = get_logger(__name__)

@reports_bp.route('/summary', methods=['GET'])
@jwt_required()
def get_summary():
    """Get user's todo summary"""
    try:
        identity = get_jwt_identity()
        
        # Count todos by status for current user
        query = TodoItem.query.filter(
            or_(
                TodoItem.creator_ad == identity,
                TodoItem.responsible_users.any(TodoItemResponsible.ad_account == identity),
                TodoItem.followers.any(TodoItemFollower.ad_account == identity)
            )
        )
        
        total = query.count()
        completed = query.filter(TodoItem.status == 'DONE').count()
        in_progress = query.filter(TodoItem.status == 'IN_PROGRESS').count()
        new = query.filter(TodoItem.status == 'NEW').count()
        
        # Overdue todos
        today = date.today()
        overdue = query.filter(
            and_(
                TodoItem.due_date < today,
                TodoItem.status != 'DONE'
            )
        ).count()
        
        # Due today
        due_today = query.filter(
            and_(
                TodoItem.due_date == today,
                TodoItem.status != 'DONE'
            )
        ).count()
        
        # Due this week
        week_end = today + timedelta(days=7)
        due_this_week = query.filter(
            and_(
                TodoItem.due_date.between(today, week_end),
                TodoItem.status != 'DONE'
            )
        ).count()
        
        # Priority distribution
        high_priority = query.filter(TodoItem.priority == 'HIGH').count()
        medium_priority = query.filter(TodoItem.priority == 'MEDIUM').count()
        low_priority = query.filter(TodoItem.priority == 'LOW').count()
        
        # Completion rate
        completion_rate = (completed / total * 100) if total > 0 else 0
        
        return jsonify({
            'summary': {
                'total': total,
                'completed': completed,
                'in_progress': in_progress,
                'new': new,
                'overdue': overdue,
                'due_today': due_today,
                'due_this_week': due_this_week,
                'completion_rate': round(completion_rate, 1)
            },
            'priority_distribution': {
                'high': high_priority,
                'medium': medium_priority,
                'low': low_priority
            }
        }), 200
        
    except Exception as e:
        logger.error(f"Error fetching summary: {str(e)}")
        return jsonify({'error': 'Failed to fetch summary'}), 500

@reports_bp.route('/activity', methods=['GET'])
@jwt_required()
def get_activity():
    """Get user's activity over time"""
    try:
        identity = get_jwt_identity()
        days = request.args.get('days', 30, type=int)
        
        # Get date range
        end_date = date.today()
        start_date = end_date - timedelta(days=days-1)
        
        # Query audit logs for the user
        logs = db.session.query(
            func.date(TodoAuditLog.timestamp).label('date'),
            func.count(TodoAuditLog.id).label('count'),
            TodoAuditLog.action
        ).filter(
            and_(
                TodoAuditLog.actor_ad == identity,
                func.date(TodoAuditLog.timestamp) >= start_date
            )
        ).group_by(
            func.date(TodoAuditLog.timestamp),
            TodoAuditLog.action
        ).all()
        
        # Organize by date and action
        activity_data = {}
        for log in logs:
            date_str = log.date.isoformat()
            if date_str not in activity_data:
                activity_data[date_str] = {'CREATE': 0, 'UPDATE': 0, 'DELETE': 0}
            activity_data[date_str][log.action] = log.count
        
        # Fill in missing dates
        current_date = start_date
        while current_date <= end_date:
            date_str = current_date.isoformat()
            if date_str not in activity_data:
                activity_data[date_str] = {'CREATE': 0, 'UPDATE': 0, 'DELETE': 0}
            current_date += timedelta(days=1)
        
        return jsonify({
            'activity': activity_data,
            'period': {
                'start_date': start_date.isoformat(),
                'end_date': end_date.isoformat(),
                'days': days
            }
        }), 200
        
    except Exception as e:
        logger.error(f"Error fetching activity: {str(e)}")
        return jsonify({'error': 'Failed to fetch activity'}), 500

@reports_bp.route('/productivity', methods=['GET'])
@jwt_required()
def get_productivity():
    """Get productivity metrics"""
    try:
        identity = get_jwt_identity()
        
        # Get date ranges
        today = date.today()
        week_start = today - timedelta(days=today.weekday())
        month_start = today.replace(day=1)
        
        # Base query for user's todos
        base_query = TodoItem.query.filter(
            or_(
                TodoItem.creator_ad == identity,
                TodoItem.responsible_users.any(TodoItemResponsible.ad_account == identity)
            )
        )
        
        # Today's completions
        today_completed = base_query.filter(
            and_(
                func.date(TodoItem.completed_at) == today,
                TodoItem.status == 'DONE'
            )
        ).count()
        
        # This week's completions
        week_completed = base_query.filter(
            and_(
                func.date(TodoItem.completed_at) >= week_start,
                TodoItem.status == 'DONE'
            )
        ).count()
        
        # This month's completions
        month_completed = base_query.filter(
            and_(
                func.date(TodoItem.completed_at) >= month_start,
                TodoItem.status == 'DONE'
            )
        ).count()
        
        # Average completion time (for completed todos)
        completed_todos = base_query.filter(
            and_(
                TodoItem.status == 'DONE',
                TodoItem.completed_at.isnot(None)
            )
        ).all()
        
        avg_completion_days = 0
        if completed_todos:
            total_days = 0
            count = 0
            for todo in completed_todos:
                if todo.completed_at and todo.created_at:
                    days = (todo.completed_at.date() - todo.created_at.date()).days
                    total_days += days
                    count += 1
            avg_completion_days = round(total_days / count, 1) if count > 0 else 0
        
        # On-time completion rate (within due date)
        on_time_todos = base_query.filter(
            and_(
                TodoItem.status == 'DONE',
                TodoItem.due_date.isnot(None),
                TodoItem.completed_at.isnot(None),
                func.date(TodoItem.completed_at) <= TodoItem.due_date
            )
        ).count()
        
        total_due_todos = base_query.filter(
            and_(
                TodoItem.status == 'DONE',
                TodoItem.due_date.isnot(None)
            )
        ).count()
        
        on_time_rate = (on_time_todos / total_due_todos * 100) if total_due_todos > 0 else 0
        
        return jsonify({
            'productivity': {
                'today_completed': today_completed,
                'week_completed': week_completed,
                'month_completed': month_completed,
                'avg_completion_days': avg_completion_days,
                'on_time_rate': round(on_time_rate, 1),
                'total_with_due_dates': total_due_todos,
                'on_time_count': on_time_todos
            }
        }), 200
        
    except Exception as e:
        logger.error(f"Error fetching productivity: {str(e)}")
        return jsonify({'error': 'Failed to fetch productivity metrics'}), 500

@reports_bp.route('/team-overview', methods=['GET'])
@jwt_required()
def get_team_overview():
    """Get team overview for todos created by current user"""
    try:
        identity = get_jwt_identity()
        
        # Get todos created by current user
        created_todos = TodoItem.query.filter(TodoItem.creator_ad == identity)
        
        # Get unique responsible users from these todos
        responsible_stats = db.session.query(
            TodoItemResponsible.ad_account,
            func.count(TodoItem.id).label('total'),
            func.sum(func.case([(TodoItem.status == 'DONE', 1)], else_=0)).label('completed'),
            func.sum(func.case([(TodoItem.status == 'IN_PROGRESS', 1)], else_=0)).label('in_progress'),
            func.sum(func.case([
                (and_(TodoItem.due_date < date.today(), TodoItem.status != 'DONE'), 1)
            ], else_=0)).label('overdue')
        ).join(
            TodoItem, TodoItemResponsible.todo_id == TodoItem.id
        ).filter(
            TodoItem.creator_ad == identity
        ).group_by(
            TodoItemResponsible.ad_account
        ).all()
        
        team_stats = []
        for stat in responsible_stats:
            completion_rate = (stat.completed / stat.total * 100) if stat.total > 0 else 0
            team_stats.append({
                'ad_account': stat.ad_account,
                'total_assigned': stat.total,
                'completed': stat.completed,
                'in_progress': stat.in_progress,
                'overdue': stat.overdue,
                'completion_rate': round(completion_rate, 1)
            })
        
        return jsonify({
            'team_overview': team_stats,
            'summary': {
                'total_team_members': len(team_stats),
                'total_assigned_todos': sum(stat['total_assigned'] for stat in team_stats),
                'total_completed': sum(stat['completed'] for stat in team_stats),
                'total_overdue': sum(stat['overdue'] for stat in team_stats)
            }
        }), 200
        
    except Exception as e:
        logger.error(f"Error fetching team overview: {str(e)}")
        return jsonify({'error': 'Failed to fetch team overview'}), 500

@reports_bp.route('/monthly-trends', methods=['GET'])
@jwt_required()
def get_monthly_trends():
    """Get monthly trends for the past year"""
    try:
        identity = get_jwt_identity()
        months = request.args.get('months', 12, type=int)
        
        # Calculate date range
        today = date.today()
        start_date = today.replace(day=1) - timedelta(days=30 * (months - 1))
        
        # Base query
        base_query = TodoItem.query.filter(
            or_(
                TodoItem.creator_ad == identity,
                TodoItem.responsible_users.any(TodoItemResponsible.ad_account == identity)
            )
        )
        
        # Get monthly statistics
        monthly_data = db.session.query(
            func.year(TodoItem.created_at).label('year'),
            func.month(TodoItem.created_at).label('month'),
            func.count(TodoItem.id).label('created'),
            func.sum(func.case([(TodoItem.status == 'DONE', 1)], else_=0)).label('completed')
        ).filter(
            and_(
                func.date(TodoItem.created_at) >= start_date,
                or_(
                    TodoItem.creator_ad == identity,
                    TodoItem.responsible_users.any(TodoItemResponsible.ad_account == identity)
                )
            )
        ).group_by(
            func.year(TodoItem.created_at),
            func.month(TodoItem.created_at)
        ).order_by(
            func.year(TodoItem.created_at),
            func.month(TodoItem.created_at)
        ).all()
        
        # Format the data
        trends = []
        for data in monthly_data:
            month_name = calendar.month_name[data.month]
            completion_rate = (data.completed / data.created * 100) if data.created > 0 else 0
            
            trends.append({
                'year': data.year,
                'month': data.month,
                'month_name': month_name,
                'created': data.created,
                'completed': data.completed,
                'completion_rate': round(completion_rate, 1)
            })
        
        return jsonify({
            'trends': trends,
            'period': {
                'months': months,
                'start_date': start_date.isoformat(),
                'end_date': today.isoformat()
            }
        }), 200
        
    except Exception as e:
        logger.error(f"Error fetching monthly trends: {str(e)}")
        return jsonify({'error': 'Failed to fetch monthly trends'}), 500