import csv
import json
import datetime
from django.http import HttpResponse
from django.utils.encoding import escape_uri_path

def flatten_json(y):
    """
    Flatten a nested json object
    """
    out = {}

    def flatten(x, name=''):
        if type(x) is dict:
            for a in x:
                flatten(x[a], name + a + '_')
        elif type(x) is list:
            i = 0
            for a in x:
                flatten(a, name + str(i) + '_')
                i += 1
        else:
            out[name[:-1]] = x

    flatten(y)
    return out

def get_signup_info_keys(queryset):
    """
    Collect all unique keys from the signup_info JSON across the queryset
    """
    keys = set()
    for obj in queryset:
        if obj.signup_info and isinstance(obj.signup_info, dict):
            # Flatten the dictionary first to get all nested keys
            flat_info = flatten_json(obj.signup_info)
            keys.update(flat_info.keys())
    return sorted(list(keys))

def get_row_data(obj):
    """
    Build a dictionary of all exportable data for a single ActivitySignup object
    """
    data = {}
    
    # 1. 基础信息
    data['ID'] = str(obj.id)
    data['活动标题'] = obj.activity.title
    data['报名时间'] = obj.signup_time
    data['状态'] = obj.get_status_display()
    
    # 2. 用户信息
    if obj.user:
        data['用户昵称'] = obj.user.nickname
        data['用户ID'] = str(obj.user.id)
        data['用户OpenID'] = obj.user.openid
        data['用户绑定手机'] = obj.user.phone_number or ''
        data['用户地区'] = f"{obj.user.country} {obj.user.province} {obj.user.city}".strip()
        data['用户注册时间'] = obj.user.created_at
    else:
        data['用户昵称'] = 'Unknown'
        data['用户ID'] = ''
        data['用户OpenID'] = ''
        data['用户绑定手机'] = ''
        data['用户地区'] = ''
        data['用户注册时间'] = ''

    # 3. 订单/发货信息
    if obj.order:
        data['关联订单ID'] = str(obj.order.id)
        data['订单状态'] = obj.order.get_status_display()
        data['收货人姓名'] = obj.order.customer_name
        data['收货电话'] = obj.order.phone_number
        data['收货地址'] = obj.order.shipping_address
        data['快递公司'] = obj.order.courier_name or ''
        data['快递单号'] = obj.order.tracking_number or ''
        data['订单总价'] = str(obj.order.total_price)
        data['商户订单号'] = obj.order.out_trade_no or ''
    else:
        data['关联订单ID'] = ''
        data['订单状态'] = ''
        data['收货人姓名'] = ''
        data['收货电话'] = ''
        data['收货地址'] = ''
        data['快递公司'] = ''
        data['快递单号'] = ''
        data['订单总价'] = ''
        data['商户订单号'] = ''

    return data

def export_signups_csv(modeladmin, request, queryset):
    """
    Export selected signups to CSV, including flattened JSON fields
    """
    opts = modeladmin.model._meta
    filename = f"{opts.verbose_name}_{datetime.datetime.now().strftime('%Y%m%d_%H%M%S')}.csv"
    
    response = HttpResponse(content_type='text/csv; charset=utf-8-sig')
    response['Content-Disposition'] = f'attachment; filename={escape_uri_path(filename)}'
    
    writer = csv.writer(response)
    
    # Fixed headers
    fixed_headers = [
        'ID', '活动标题', '状态', '报名时间',
        '用户ID', '用户昵称', '用户OpenID', '用户绑定手机', '用户地区', '用户注册时间',
        '关联订单ID', '订单状态', '收货人姓名', '收货电话', '收货地址', '快递公司', '快递单号', '订单总价', '商户订单号'
    ]
    
    # Get dynamic JSON keys
    json_keys = get_signup_info_keys(queryset)
    
    # Write header
    writer.writerow(fixed_headers + json_keys)
    
    # Write data
    for obj in queryset:
        row_data = get_row_data(obj)
        
        # Build the row based on fixed_headers order
        row = []
        for header in fixed_headers:
            val = row_data.get(header, '')
            if isinstance(val, (datetime.datetime, datetime.date)):
                val = val.strftime('%Y-%m-%d %H:%M:%S')
            row.append(str(val))
        
        # Add JSON data
        flat_info = {}
        if obj.signup_info and isinstance(obj.signup_info, dict):
            flat_info = flatten_json(obj.signup_info)
            
        for key in json_keys:
            val = flat_info.get(key, '')
            if val is None:
                val = ''
            row.append(str(val))
            
        writer.writerow(row)
        
    return response

export_signups_csv.short_description = "导出选中报名记录为 CSV (含发货/详细信息)"

def export_signups_excel(modeladmin, request, queryset):
    """
    Export selected signups to Excel, including flattened JSON fields
    """
    try:
        from openpyxl import Workbook
    except ImportError:
        modeladmin.message_user(request, "请先安装 openpyxl 库以使用 Excel 导出功能", level='error')
        return

    opts = modeladmin.model._meta
    filename = f"{opts.verbose_name}_{datetime.datetime.now().strftime('%Y%m%d_%H%M%S')}.xlsx"
    
    response = HttpResponse(
        content_type='application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
    )
    response['Content-Disposition'] = f'attachment; filename={escape_uri_path(filename)}'
    
    wb = Workbook()
    ws = wb.active
    ws.title = str(opts.verbose_name)[:31]  # Sheet name limit is 31 chars
    
    # Fixed headers
    fixed_headers = [
        'ID', '活动标题', '状态', '报名时间',
        '用户ID', '用户昵称', '用户OpenID', '用户绑定手机', '用户地区', '用户注册时间',
        '关联订单ID', '订单状态', '收货人姓名', '收货电话', '收货地址', '快递公司', '快递单号', '订单总价', '商户订单号'
    ]
    
    # Get dynamic JSON keys
    json_keys = get_signup_info_keys(queryset)
    
    # Write header
    ws.append(fixed_headers + json_keys)
    
    # Write data
    for obj in queryset:
        row_data = get_row_data(obj)
        
        row = []
        for header in fixed_headers:
            val = row_data.get(header, '')
            # Excel handles datetime natively, but we need to remove timezone info if present to avoid Excel errors or warnings depending on version
            # Here we convert to naive datetime for simplicity or keep as is if library handles it. 
            # openpyxl supports datetime, but usually it's safer to remove tzinfo for compatibility.
            if isinstance(val, (datetime.datetime, datetime.date)):
                 if hasattr(val, 'replace'):
                     val = val.replace(tzinfo=None)
            
            # Ensure None becomes empty string
            if val is None:
                val = ""
            row.append(val)

        # Add JSON data
        flat_info = {}
        if obj.signup_info and isinstance(obj.signup_info, dict):
            flat_info = flatten_json(obj.signup_info)
            
        for key in json_keys:
            val = flat_info.get(key, '')
            if val is None:
                val = ''
            row.append(str(val)) # JSON values as strings
            
        ws.append(row)
        
    wb.save(response)
    return response

export_signups_excel.short_description = "导出选中报名记录为 Excel (含发货/详细信息)"