"""
Excel Import/Export API Routes
處理 Excel 檔案的匯入和匯出功能
"""

import os
import uuid
from datetime import datetime, date
from flask import Blueprint, request, jsonify, send_file, current_app
from flask_jwt_extended import jwt_required, get_jwt_identity, get_jwt
from werkzeug.utils import secure_filename
import pandas as pd
from openpyxl import Workbook
from openpyxl.styles import Font, Alignment, PatternFill
from openpyxl.utils.dataframe import dataframe_to_rows
from sqlalchemy import or_, and_
from models import (
    db, TodoItem, TodoItemResponsible, TodoItemFollower,
    TodoAuditLog
)
from utils.logger import get_logger
from utils.ldap_utils import validate_ad_accounts
import tempfile
import zipfile

excel_bp = Blueprint('excel', __name__)
logger = get_logger(__name__)

# 允許的檔案類型
ALLOWED_EXTENSIONS = {'xlsx', 'xls', 'csv'}

def allowed_file(filename):
    """檢查檔案類型是否允許"""
    return '.' in filename and filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS

def parse_date(date_str):
    """解析日期字串"""
    if pd.isna(date_str) or not date_str:
        return None
    
    if isinstance(date_str, datetime):
        return date_str.date()
    
    if isinstance(date_str, date):
        return date_str
    
    # 嘗試多種日期格式
    date_formats = ['%Y-%m-%d', '%Y/%m/%d', '%d/%m/%Y', '%m/%d/%Y', '%Y%m%d']
    for fmt in date_formats:
        try:
            return datetime.strptime(str(date_str), fmt).date()
        except ValueError:
            continue
    
    return None

@excel_bp.route('/upload', methods=['POST'])
@jwt_required()
def upload_excel():
    """Upload and parse Excel file for todo import"""
    try:
        identity = get_jwt_identity()
        
        if 'file' not in request.files:
            return jsonify({'error': '沒有選擇檔案'}), 400
        
        file = request.files['file']
        if file.filename == '':
            return jsonify({'error': '沒有選擇檔案'}), 400
        
        if not allowed_file(file.filename):
            return jsonify({'error': '檔案類型不支援，請上傳 .xlsx, .xls 或 .csv 檔案'}), 400
        
        # 儲存檔案到暫存目錄
        filename = secure_filename(file.filename)
        temp_dir = current_app.config.get('TEMP_FOLDER', tempfile.gettempdir())
        filepath = os.path.join(temp_dir, f"{uuid.uuid4()}_{filename}")
        file.save(filepath)
        
        try:
            # 讀取 Excel/CSV 檔案
            if filename.endswith('.csv'):
                df = pd.read_csv(filepath, encoding='utf-8')
            else:
                df = pd.read_excel(filepath)
            
            # 驗證必要欄位
            required_columns = ['標題', 'title']  # 支援中英文欄位名
            title_column = None
            for col in required_columns:
                if col in df.columns:
                    title_column = col
                    break
            
            if not title_column:
                return jsonify({
                    'error': '找不到必要欄位「標題」或「title」',
                    'columns': list(df.columns)
                }), 400
            
            # 解析資料
            todos_data = []
            errors = []
            
            for idx, row in df.iterrows():
                try:
                    # 必要欄位
                    title = str(row[title_column]).strip()
                    if not title or title == 'nan':
                        errors.append(f'第 {idx + 2} 行：標題不能為空')
                        continue
                    
                    # 選擇性欄位
                    description = str(row.get('描述', row.get('description', ''))).strip()
                    if description == 'nan':
                        description = ''
                    
                    # 狀態
                    status_mapping = {
                        '新建': 'NEW', '進行中': 'DOING', '完成': 'DONE', '阻塞': 'BLOCKED',
                        'NEW': 'NEW', 'DOING': 'DOING', 'DONE': 'DONE', 'BLOCKED': 'BLOCKED',
                        '新': 'NEW', '進行': 'DOING', '完': 'DONE', '阻': 'BLOCKED'
                    }
                    status_str = str(row.get('狀態', row.get('status', 'NEW'))).strip()
                    status = status_mapping.get(status_str, 'NEW')
                    
                    # 優先級
                    priority_mapping = {
                        '緊急': 'URGENT', '高': 'HIGH', '中': 'MEDIUM', '低': 'LOW',
                        'URGENT': 'URGENT', 'HIGH': 'HIGH', 'MEDIUM': 'MEDIUM', 'LOW': 'LOW',
                        '緊急優先級': 'URGENT', '高優先級': 'HIGH', '中優先級': 'MEDIUM', '低優先級': 'LOW'
                    }
                    priority_str = str(row.get('優先級', row.get('priority', 'MEDIUM'))).strip()
                    priority = priority_mapping.get(priority_str, 'MEDIUM')
                    
                    # 到期日
                    due_date = parse_date(row.get('到期日', row.get('due_date')))
                    
                    # 負責人 (用分號或逗號分隔)
                    responsible_str = str(row.get('負責人', row.get('responsible_users', ''))).strip()
                    responsible_users = []
                    if responsible_str and responsible_str != 'nan':
                        responsible_users = [user.strip() for user in responsible_str.replace(',', ';').split(';') if user.strip()]
                    
                    # 追蹤人
                    followers_str = str(row.get('追蹤人', row.get('followers', ''))).strip()
                    followers = []
                    if followers_str and followers_str != 'nan':
                        followers = [user.strip() for user in followers_str.replace(',', ';').split(';') if user.strip()]
                    
                    todos_data.append({
                        'row': idx + 2,
                        'title': title,
                        'description': description,
                        'status': status,
                        'priority': priority,
                        'due_date': due_date.isoformat() if due_date else None,
                        'responsible_users': responsible_users,
                        'followers': followers
                    })
                    
                except Exception as e:
                    errors.append(f'第 {idx + 2} 行解析錯誤: {str(e)}')
            
            # 清理暫存檔案
            os.unlink(filepath)
            
            return jsonify({
                'data': todos_data,
                'total': len(todos_data),
                'errors': errors,
                'columns': list(df.columns)
            }), 200
            
        except Exception as e:
            # 清理暫存檔案
            if os.path.exists(filepath):
                os.unlink(filepath)
            raise e
            
    except Exception as e:
        logger.error(f"Excel upload error: {str(e)}")
        return jsonify({'error': f'檔案處理失敗: {str(e)}'}), 500

@excel_bp.route('/import', methods=['POST'])
@jwt_required()
def import_todos():
    """Import todos from parsed Excel data"""
    try:
        identity = get_jwt_identity()
        claims = get_jwt()
        data = request.get_json()
        
        todos_data = data.get('todos', [])
        if not todos_data:
            return jsonify({'error': '沒有要匯入的資料'}), 400
        
        imported_count = 0
        errors = []
        
        for todo_data in todos_data:
            try:
                # 驗證負責人和追蹤人的 AD 帳號
                responsible_users = todo_data.get('responsible_users', [])
                followers = todo_data.get('followers', [])
                
                if responsible_users:
                    valid_responsible = validate_ad_accounts(responsible_users)
                    invalid_responsible = set(responsible_users) - set(valid_responsible.keys())
                    if invalid_responsible:
                        errors.append({
                            'row': todo_data.get('row', '?'),
                            'error': f'無效的負責人帳號: {", ".join(invalid_responsible)}'
                        })
                        continue
                
                if followers:
                    valid_followers = validate_ad_accounts(followers)
                    invalid_followers = set(followers) - set(valid_followers.keys())
                    if invalid_followers:
                        errors.append({
                            'row': todo_data.get('row', '?'),
                            'error': f'無效的追蹤人帳號: {", ".join(invalid_followers)}'
                        })
                        continue
                
                # 建立待辦事項
                due_date = None
                if todo_data.get('due_date'):
                    due_date = datetime.strptime(todo_data['due_date'], '%Y-%m-%d').date()
                
                todo = TodoItem(
                    id=str(uuid.uuid4()),
                    title=todo_data['title'],
                    description=todo_data.get('description', ''),
                    status=todo_data.get('status', 'NEW'),
                    priority=todo_data.get('priority', 'MEDIUM'),
                    due_date=due_date,
                    creator_ad=identity,
                    creator_display_name=claims.get('display_name', identity),
                    creator_email=claims.get('email', ''),
                    starred=False
                )
                db.session.add(todo)
                
                # 新增負責人
                if responsible_users:
                    for account in responsible_users:
                        responsible = TodoItemResponsible(
                            todo_id=todo.id,
                            ad_account=account,
                            added_by=identity
                        )
                        db.session.add(responsible)
                
                # 新增追蹤人
                if followers:
                    for account in followers:
                        follower = TodoItemFollower(
                            todo_id=todo.id,
                            ad_account=account,
                            added_by=identity
                        )
                        db.session.add(follower)
                
                # 新增稽核記錄
                audit = TodoAuditLog(
                    actor_ad=identity,
                    todo_id=todo.id,
                    action='CREATE',
                    detail={
                        'source': 'excel_import',
                        'title': todo.title,
                        'row': todo_data.get('row')
                    }
                )
                db.session.add(audit)
                
                imported_count += 1
                
            except Exception as e:
                errors.append({
                    'row': todo_data.get('row', '?'),
                    'error': str(e)
                })
        
        db.session.commit()
        
        logger.info(f"Excel import completed: {imported_count} todos imported by {identity}")
        
        return jsonify({
            'imported': imported_count,
            'errors': errors,
            'total_processed': len(todos_data)
        }), 200
        
    except Exception as e:
        db.session.rollback()
        logger.error(f"Excel import error: {str(e)}")
        return jsonify({'error': '匯入失敗'}), 500

@excel_bp.route('/export', methods=['GET'])
@jwt_required()
def export_todos():
    """Export todos to Excel"""
    try:
        identity = get_jwt_identity()
        
        # 篩選參數
        status = request.args.get('status')
        priority = request.args.get('priority')
        due_from = request.args.get('due_from')
        due_to = request.args.get('due_to')
        view_type = request.args.get('view', 'all')
        
        # 查詢待辦事項
        query = TodoItem.query
        
        # 套用檢視類型篩選
        if view_type == 'created':
            query = query.filter(TodoItem.creator_ad == identity)
        elif view_type == 'responsible':
            query = query.join(TodoItemResponsible).filter(
                TodoItemResponsible.ad_account == identity
            )
        elif view_type == 'following':
            query = query.join(TodoItemFollower).filter(
                TodoItemFollower.ad_account == identity
            )
        else:  # all
            query = query.filter(
                or_(
                    TodoItem.creator_ad == identity,
                    TodoItem.responsible_users.any(TodoItemResponsible.ad_account == identity),
                    TodoItem.followers.any(TodoItemFollower.ad_account == identity)
                )
            )
        
        # 套用其他篩選條件
        if status:
            query = query.filter(TodoItem.status == status)
        if priority:
            query = query.filter(TodoItem.priority == priority)
        if due_from:
            query = query.filter(TodoItem.due_date >= datetime.strptime(due_from, '%Y-%m-%d').date())
        if due_to:
            query = query.filter(TodoItem.due_date <= datetime.strptime(due_to, '%Y-%m-%d').date())
        
        todos = query.order_by(TodoItem.created_at.desc()).all()
        
        # 準備資料
        data = []
        for todo in todos:
            # 取得負責人和追蹤人
            responsible_users = [r.ad_account for r in todo.responsible_users]
            followers = [f.ad_account for f in todo.followers]
            
            # 狀態和優先級的中文對應
            status_mapping = {'NEW': '新建', 'DOING': '進行中', 'DONE': '完成', 'BLOCKED': '阻塞'}
            priority_mapping = {'URGENT': '緊急', 'HIGH': '高', 'MEDIUM': '中', 'LOW': '低'}
            
            data.append({
                '編號': todo.id,
                '標題': todo.title,
                '描述': todo.description,
                '狀態': status_mapping.get(todo.status, todo.status),
                '優先級': priority_mapping.get(todo.priority, todo.priority),
                '到期日': todo.due_date.strftime('%Y-%m-%d') if todo.due_date else '',
                '建立者': todo.creator_ad,
                '建立時間': todo.created_at.strftime('%Y-%m-%d %H:%M:%S'),
                '完成時間': todo.completed_at.strftime('%Y-%m-%d %H:%M:%S') if todo.completed_at else '',
                '負責人': '; '.join(responsible_users),
                '追蹤人': '; '.join(followers),
                '星號標記': '是' if todo.starred else '否'
            })
        
        # 建立 Excel 檔案
        df = pd.DataFrame(data)
        
        # 建立暫存檔案
        temp_file = tempfile.NamedTemporaryFile(delete=False, suffix='.xlsx')
        temp_filename = temp_file.name
        temp_file.close()
        
        # 使用 openpyxl 建立更美觀的 Excel
        wb = Workbook()
        ws = wb.active
        ws.title = "待辦清單"
        
        # 標題樣式
        header_font = Font(bold=True, color="FFFFFF")
        header_fill = PatternFill(start_color="4472C4", end_color="4472C4", fill_type="solid")
        header_alignment = Alignment(horizontal="center", vertical="center")
        
        # 寫入標題
        if not df.empty:
            for r_idx, row in enumerate(dataframe_to_rows(df, index=False, header=True), 1):
                for c_idx, value in enumerate(row, 1):
                    cell = ws.cell(row=r_idx, column=c_idx, value=value)
                    if r_idx == 1:  # 標題行
                        cell.font = header_font
                        cell.fill = header_fill
                        cell.alignment = header_alignment
        
        # 自動調整列寬
        for column in ws.columns:
            max_length = 0
            column_letter = column[0].column_letter
            for cell in column:
                try:
                    if len(str(cell.value)) > max_length:
                        max_length = len(str(cell.value))
                except:
                    pass
            adjusted_width = min(max_length + 2, 50)
            ws.column_dimensions[column_letter].width = adjusted_width
        
        wb.save(temp_filename)
        
        # 產生檔案名稱
        timestamp = datetime.now().strftime("%Y%m%d_%H%M%S")
        filename = f"todos_{timestamp}.xlsx"
        
        logger.info(f"Excel export: {len(todos)} todos exported by {identity}")
        
        return send_file(
            temp_filename,
            as_attachment=True,
            download_name=filename,
            mimetype='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'
        )
        
    except Exception as e:
        logger.error(f"Excel export error: {str(e)}")
        return jsonify({'error': '匯出失敗'}), 500

@excel_bp.route('/template', methods=['GET'])
@jwt_required()
def download_template():
    """Download Excel import template"""
    try:
        # 建立範本資料
        template_data = {
            '標題': ['範例待辦事項1', '範例待辦事項2'],
            '描述': ['這是第一個範例的詳細描述', '這是第二個範例的詳細描述'],
            '狀態': ['新建', '進行中'],
            '優先級': ['高', '中'],
            '到期日': ['2025-12-31', '2026-01-15'],
            '負責人': ['user1@panjit.com.tw', 'user2@panjit.com.tw'],
            '追蹤人': ['user3@panjit.com.tw;user4@panjit.com.tw', 'user5@panjit.com.tw']
        }
        
        # 說明資料
        instructions = {
            '欄位說明': [
                '標題 (必填)',
                '描述 (選填)',
                '狀態: 新建/進行中/完成/阻塞',
                '優先級: 緊急/高/中/低',
                '到期日: YYYY-MM-DD 格式',
                '負責人: AD帳號，多人用分號分隔',
                '追蹤人: AD帳號，多人用分號分隔'
            ],
            '說明': [
                '請填入待辦事項的標題',
                '可選填詳細描述',
                '可選填 NEW/DOING/DONE/BLOCKED',
                '可選填 URGENT/HIGH/MEDIUM/LOW',
                '例如: 2024-12-31',
                '例如: john@panjit.com.tw',
                '例如: mary@panjit.com.tw;tom@panjit.com.tw'
            ]
        }
        
        # 建立暫存檔案
        temp_file = tempfile.NamedTemporaryFile(delete=False, suffix='.xlsx')
        temp_filename = temp_file.name
        temp_file.close()
        
        # 建立 Excel 檔案
        wb = Workbook()
        
        # 範本資料工作表
        ws_data = wb.active
        ws_data.title = "匯入範本"
        df_template = pd.DataFrame(template_data)
        
        for r_idx, row in enumerate(dataframe_to_rows(df_template, index=False, header=True), 1):
            for c_idx, value in enumerate(row, 1):
                ws_data.cell(row=r_idx, column=c_idx, value=value)
        
        # 說明工作表
        ws_help = wb.create_sheet("使用說明")
        df_help = pd.DataFrame(instructions)
        
        for r_idx, row in enumerate(dataframe_to_rows(df_help, index=False, header=True), 1):
            for c_idx, value in enumerate(row, 1):
                ws_help.cell(row=r_idx, column=c_idx, value=value)
        
        # 樣式設定
        for ws in [ws_data, ws_help]:
            for column in ws.columns:
                max_length = 0
                column_letter = column[0].column_letter
                for cell in column:
                    try:
                        if len(str(cell.value)) > max_length:
                            max_length = len(str(cell.value))
                    except:
                        pass
                adjusted_width = min(max_length + 2, 50)
                ws.column_dimensions[column_letter].width = adjusted_width
        
        wb.save(temp_filename)
        
        logger.info(f"Template downloaded by {get_jwt_identity()}")
        
        return send_file(
            temp_filename,
            as_attachment=True,
            download_name="todo_import_template.xlsx",
            mimetype='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'
        )
        
    except Exception as e:
        logger.error(f"Template download error: {str(e)}")
        return jsonify({'error': '範本下載失敗'}), 500