const Property = require('../property/propertyModel')
const Category = require('../category/categoryModel')
const PropertyStatus = require('../propertyStatus/propertyStatusModel')
const Warehouse = require('../warehouse/warehouseModel')
const WarehouseItem = require('../warehouseItem/warehouseItemModel')
const WarehouseItemTransaction = require('../warehouseItem/warehouseItemTransactionModel')
const User = require('../user/userModel')
const Role = require('../role/roleModel')
const { getSignedUrl } = require('../file/fileService')

/**
 * Aggregates live dashboard statistics across properties, warehouses, inventory, and users
 */
const getDashboardStats = async () => {
    // 1. Overview counts
    const [
        totalProperties,
        totalAreaResult,
        totalWarehouseItems,
        totalWarehouses,
        totalWarehouseTransactions,
        totalUsers,
        totalCategories,
        totalRoles,
    ] = await Promise.all([
        Property.countDocuments({ isActive: { $ne: false } }),
        Property.aggregate([
            { $match: { isActive: { $ne: false }, area: { $gt: 0 } } },
            { $group: { _id: null, totalArea: { $sum: '$area' } } },
        ]),
        WarehouseItem.countDocuments({ isActive: { $ne: false } }),
        Warehouse.countDocuments(),
        WarehouseItemTransaction.countDocuments(),
        User.countDocuments({ isActive: { $ne: false } }),
        Category.countDocuments(),
        Role.countDocuments(),
    ])

    const totalArea = totalAreaResult?.[0]?.totalArea || 0

    // 2. Properties grouped by Category
    const propertiesByCategoryRaw = await Property.aggregate([
        { $match: { isActive: { $ne: false } } },
        {
            $group: {
                _id: '$category',
                count: { $sum: 1 },
                totalArea: { $sum: { $ifNull: ['$area', 0] } },
            },
        },
        {
            $lookup: {
                from: 'categories',
                localField: '_id',
                foreignField: '_id',
                as: 'categoryDoc',
            },
        },
        { $unwind: { path: '$categoryDoc', preserveNullAndEmptyArrays: true } },
        { $sort: { count: -1 } },
    ])

    const propertiesByCategory = propertiesByCategoryRaw.map((item) => ({
        categoryId: item._id,
        name: item.categoryDoc?.nativeName || item.categoryDoc?.englishName || 'بدون دسته‌بندی',
        englishName: item.categoryDoc?.englishName || 'Uncategorized',
        count: item.count,
        totalArea: item.totalArea || 0,
        percentage: totalProperties > 0 ? Math.round((item.count / totalProperties) * 100) : 0,
    }))

    // 3. Properties grouped by Status
    const propertiesByStatusRaw = await Property.aggregate([
        { $match: { isActive: { $ne: false } } },
        {
            $group: {
                _id: '$status',
                count: { $sum: 1 },
            },
        },
        {
            $lookup: {
                from: 'propertystatuses',
                localField: '_id',
                foreignField: '_id',
                as: 'statusDoc',
            },
        },
        { $unwind: { path: '$statusDoc', preserveNullAndEmptyArrays: true } },
        { $sort: { count: -1 } },
    ])

    const propertiesByStatus = propertiesByStatusRaw.map((item) => ({
        statusId: item._id,
        name: item.statusDoc?.nativeName || item.statusDoc?.englishName || 'نامشخص',
        englishName: item.statusDoc?.englishName || 'Unknown',
        color: item.statusDoc?.color || '#3b82f6',
        count: item.count,
        percentage: totalProperties > 0 ? Math.round((item.count / totalProperties) * 100) : 0,
    }))

    // 4. Warehouse transactions summary (IN vs OUT)
    const warehouseFlowRaw = await WarehouseItemTransaction.aggregate([
        {
            $group: {
                _id: '$type',
                count: { $sum: 1 },
                totalQuantity: { $sum: '$quantity' },
            },
        },
    ])

    const warehouseFlow = {
        inCount: warehouseFlowRaw.find((f) => f._id === 'IN')?.count || 0,
        outCount: warehouseFlowRaw.find((f) => f._id === 'OUT')?.count || 0,
        inQuantity: warehouseFlowRaw.find((f) => f._id === 'IN')?.totalQuantity || 0,
        outQuantity: warehouseFlowRaw.find((f) => f._id === 'OUT')?.totalQuantity || 0,
    }

    // 5. Recent registered properties (Last 6)
    const recentPropertiesRaw = await Property.find({ isActive: { $ne: false } })
        .sort({ createdAt: -1 })
        .limit(6)
        .populate('category', 'nativeName englishName')
        .populate('status', 'nativeName englishName color')
        .lean()

    const recentProperties = await Promise.all(
        recentPropertiesRaw.map(async (prop) => {
            let thumb = null
            if (prop.mainImageUrls && prop.mainImageUrls.length > 0) {
                thumb = await getSignedUrl(prop.mainImageUrls[0], 'properties').catch(() => null)
            }
            return {
                _id: prop._id,
                propertyCode: prop.propertyCode || prop._id.toString().slice(-6),
                name: prop.name || 'ملک بدون عنوان',
                category: prop.category?.nativeName || 'عمومی',
                status: prop.status?.nativeName || 'عادی',
                statusColor: prop.status?.color || '#3b82f6',
                ownerName: prop.ownerName || '—',
                area: prop.area || 0,
                dong: prop.dong || 6,
                imageUrl: thumb || 'https://cloud.mbmanager.ir/images/item-no-image.png',
                registrationPlate: prop.registrationPlate || '—',
                createdAt: prop.createdAt,
            }
        })
    )

    // 6. Recent warehouse transactions (Last 6)
    const recentWarehouseTransactionsRaw = await WarehouseItemTransaction.find()
        .sort({ createdAt: -1 })
        .limit(6)
        .populate('item', 'nameFa nameEn code unitFa')
        .populate('warehouse', 'name location')
        .lean()

    const recentWarehouseTransactions = recentWarehouseTransactionsRaw.map((tx) => ({
        _id: tx._id,
        type: tx.type, // 'IN' | 'OUT'
        quantity: tx.quantity,
        unit: tx.unit || tx.item?.unitFa || 'عدد',
        itemName: tx.item?.nameFa || 'کالای نامشخص',
        itemCode: tx.item?.code || '—',
        warehouseName: tx.warehouse?.name || 'انبار مرکزی',
        reason: tx.reason || (tx.type === 'IN' ? 'ورود به انبار' : 'خروج از انبار'),
        actorName: tx.actorName || 'کاربر سیستم',
        date: tx.date || tx.createdAt,
    }))

    // 7. Monthly Property & Warehouse Trend (Last 6 months)
    const sixMonthsAgo = new Date()
    sixMonthsAgo.setMonth(sixMonthsAgo.getMonth() - 5)
    sixMonthsAgo.setDate(1)
    sixMonthsAgo.setHours(0, 0, 0, 0)

    const monthlyPropertiesRaw = await Property.aggregate([
        { $match: { createdAt: { $gte: sixMonthsAgo }, isActive: { $ne: false } } },
        {
            $group: {
                _id: {
                    year: { $year: '$createdAt' },
                    month: { $month: '$createdAt' },
                },
                count: { $sum: 1 },
            },
        },
        { $sort: { '_id.year': 1, '_id.month': 1 } },
    ])

    const monthlyWarehouseRaw = await WarehouseItemTransaction.aggregate([
        { $match: { createdAt: { $gte: sixMonthsAgo } } },
        {
            $group: {
                _id: {
                    year: { $year: '$createdAt' },
                    month: { $month: '$createdAt' },
                    type: '$type',
                },
                count: { $sum: 1 },
            },
        },
        { $sort: { '_id.year': 1, '_id.month': 1 } },
    ])

    return {
        overview: {
            totalProperties,
            totalArea,
            totalWarehouseItems,
            totalWarehouses,
            totalWarehouseTransactions,
            totalUsers,
            totalCategories,
            totalRoles,
        },
        propertiesByCategory,
        propertiesByStatus,
        warehouseFlow,
        recentProperties,
        recentWarehouseTransactions,
        monthlyTrend: {
            properties: monthlyPropertiesRaw,
            warehouse: monthlyWarehouseRaw,
        },
    }
}

module.exports = {
    getDashboardStats,
}