/**
 * 建立生產工單頁面
 * 動態 BOM 表單：選擇倉庫 → 選擇原物料 → 選擇批號 → 輸入用量
 */

import { useState, useEffect } from "react";
import { Trash2, Plus, ArrowLeft, Save, Factory } from "lucide-react";
import { formatQuantity } from "@/lib/utils";
import { Button } from "@/Components/ui/button";
import AuthenticatedLayout from "@/Layouts/AuthenticatedLayout";
import { router, useForm, Head, Link } from "@inertiajs/react";
import { toast } from "sonner";
import { getBreadcrumbs } from "@/utils/breadcrumb";
import { SearchableSelect } from "@/Components/ui/searchable-select";
import { Input } from "@/Components/ui/input";
import { Label } from "@/Components/ui/label";
import { Textarea } from "@/Components/ui/textarea";
import { Table, TableBody, TableCell, TableHead, TableHeader, TableRow } from "@/Components/ui/table";

interface Product {
    id: number;
    name: string;
    code: string;
    base_unit?: { id: number; name: string } | null;
}

interface Warehouse {
    id: number;
    name: string;
}



interface InventoryOption {
    id: number;
    product_id: number;
    product_name: string;
    product_code: string;
    warehouse_id: number;
    warehouse_name: string;
    batch_number: string;
    box_number: string | null;
    quantity: number;
    arrival_date: string | null;
    expiry_date: string | null;
    unit_name: string | null;
    base_unit_id?: number;
    base_unit_name?: string;
    large_unit_id?: number;
    large_unit_name?: string;
    conversion_rate?: number;
}

interface BomItem {
    // 後端必填
    inventory_id: string; // 所選庫存記錄 ID（特定批號）
    quantity_used: string; // 轉換後的最終數量（基本單位）
    unit_id: string; // 單位 ID（通常為基本單位 ID）

    // UI 狀態
    ui_warehouse_id: string; // 來源倉庫
    ui_product_id: string; // 批號列表篩選
    ui_input_quantity: string; // 使用者輸入數量
    ui_selected_unit: 'base' | 'large'; // 使用者選擇單位

    // UI 輔助 / 快取
    ui_product_name?: string;
    ui_batch_number?: string;
    ui_available_qty?: number;
    ui_expiry_date?: string;
    ui_conversion_rate?: number;
    ui_base_unit_name?: string;
    ui_large_unit_name?: string;
    ui_base_unit_id?: number;
    ui_large_unit_id?: number;
}

interface Props {
    products: Product[];
    warehouses: Warehouse[];
}

export default function Create({ products, warehouses }: Props) {
    const [selectedWarehouse, setSelectedWarehouse] = useState<string>(""); // 產出倉庫
    // 快取對照表：product_id -> inventories across warehouses
    const [productInventoryMap, setProductInventoryMap] = useState<Record<string, InventoryOption[]>>({});
    const [loadingProducts, setLoadingProducts] = useState<Record<string, boolean>>({});

    const [bomItems, setBomItems] = useState<BomItem[]>([]);

    // 多配方支援
    const [recipes, setRecipes] = useState<any[]>([]);
    const [selectedRecipeId, setSelectedRecipeId] = useState<string>("");

    const { data, setData, processing, errors } = useForm({
        product_id: "",
        warehouse_id: "",
        output_quantity: "",
        // 移除成品批號、生產日期、有效日期，這些欄位改在完工時處理或自動記錄
        remark: "",
        items: [] as { inventory_id: number; quantity_used: number; unit_id: number | null }[],
    });

    // 獲取特定商品在各倉庫的庫存分佈
    const fetchProductInventories = async (productId: string) => {
        if (!productId) return;
        // 如果已經在載入中，則跳過，但如果已經有資料，還是可以考慮重新抓取以確保最新，這裡保持現狀或增加強制更新參數
        if (loadingProducts[productId]) return;

        setLoadingProducts(prev => ({ ...prev, [productId]: true }));
        try {
            const res = await fetch(route('api.production.products.inventories', productId));
            const data = await res.json();
            setProductInventoryMap(prev => ({ ...prev, [productId]: data }));
        } catch (e) {
            console.error(e);
        } finally {
            setLoadingProducts(prev => ({ ...prev, [productId]: false }));
        }
    };

    // 同步 warehouse_id 到 form data (Output)
    useEffect(() => {
        setData('warehouse_id', selectedWarehouse);
    }, [selectedWarehouse]);

    // 新增 BOM 項目
    const addBomItem = () => {
        setBomItems([...bomItems, {
            inventory_id: "",
            quantity_used: "",
            unit_id: "",
            ui_warehouse_id: "",
            ui_product_id: "",
            ui_input_quantity: "",
            ui_selected_unit: 'base',
        }]);
    };

    // 移除 BOM 項目
    const removeBomItem = (index: number) => {
        setBomItems(bomItems.filter((_, i) => i !== index));
    };

    // 更新 BOM 項目邏輯
    const updateBomItem = (index: number, field: keyof BomItem, value: any) => {
        const updated = [...bomItems];
        const item = { ...updated[index], [field]: value };

        // 1. 當選擇商品變更時 -> 載入庫存分佈並重置後續欄位
        if (field === 'ui_product_id') {
            item.ui_warehouse_id = "";
            item.inventory_id = "";
            item.quantity_used = "";
            item.unit_id = "";
            item.ui_input_quantity = "";
            item.ui_selected_unit = "base";
            // 清除 cache 資訊
            delete item.ui_product_name;
            delete item.ui_batch_number;
            delete item.ui_available_qty;
            delete item.ui_expiry_date;
            delete item.ui_conversion_rate;
            delete item.ui_base_unit_name;
            delete item.ui_large_unit_name;
            delete item.ui_base_unit_id;
            delete item.ui_large_unit_id;

            if (value) {
                const prod = products.find(p => String(p.id) === value);
                if (prod) {
                    item.ui_product_name = prod.name;
                    item.ui_base_unit_name = prod.base_unit?.name || '';
                }
                fetchProductInventories(value);
            }
        }

        // 2. 當選擇來源倉庫變更時 -> 重置批號與相關資訊 (保留數量)
        if (field === 'ui_warehouse_id') {
            item.inventory_id = "";
            // 不重置數量
            // item.quantity_used = "";
            // item.ui_input_quantity = "";
            // item.ui_selected_unit = "base";

            // 清除某些 cache
            delete item.ui_batch_number;
            delete item.ui_available_qty;
            delete item.ui_expiry_date;
        }

        // 3. 當選擇批號 (Inventory ID) 變更時 -> 載入該批號資訊
        if (field === 'inventory_id' && value) {
            const currentOptions = productInventoryMap[item.ui_product_id] || [];
            const inv = currentOptions.find(i => String(i.id) === value);
            if (inv) {
                item.ui_warehouse_id = String(inv.warehouse_id);
                item.ui_batch_number = inv.batch_number;
                item.ui_available_qty = inv.quantity;
                item.ui_expiry_date = inv.expiry_date || '';

                // 單位與轉換率
                item.ui_base_unit_name = inv.unit_name || '';
                item.ui_base_unit_id = inv.base_unit_id;
                item.ui_conversion_rate = inv.conversion_rate || 1;

                // 預設單位
                item.ui_selected_unit = 'base';
                item.unit_id = String(inv.base_unit_id || '');

                // 不重置數量，但如果原本沒數量可以從庫存帶入 (選填，通常配方已帶入則保留配方)
                if (!item.ui_input_quantity) {
                    item.ui_input_quantity = formatQuantity(inv.quantity);
                }
            }
        }

        // 4. 計算最終數量 (Base Quantity)
        if (field === 'ui_input_quantity' || field === 'ui_selected_unit' || field === 'inventory_id') {
            const inputQty = parseFloat(item.ui_input_quantity || '0');
            const rate = item.ui_conversion_rate || 1;

            if (item.ui_selected_unit === 'large') {
                item.quantity_used = String(inputQty * rate);
                item.unit_id = String(item.ui_base_unit_id || '');
            } else {
                item.quantity_used = String(inputQty);
                item.unit_id = String(item.ui_base_unit_id || '');
            }
        }

        updated[index] = item;
        setBomItems(updated);
    };

    // 同步 BOM items 到表單 data
    useEffect(() => {
        setData('items', bomItems.map(item => ({
            inventory_id: Number(item.inventory_id),
            quantity_used: Number(item.quantity_used),
            unit_id: item.unit_id ? Number(item.unit_id) : null
        })));
    }, [bomItems]);

    // 應用配方到表單 (獨立函式)
    const applyRecipe = (recipe: any) => {
        if (!recipe || !recipe.items) return;

        const yieldQty = parseFloat(recipe.yield_quantity || "0") || 1;
        // 自動帶入配方標準產量
        setData('output_quantity', String(yieldQty));

        const newBomItems: BomItem[] = recipe.items.map((item: any) => {
            const baseQty = parseFloat(item.quantity || "0");
            const calculatedQty = baseQty; // 保持精度

            // 若有配方商品，預先載入庫存分佈
            if (item.product_id) {
                fetchProductInventories(String(item.product_id));
            }

            return {
                inventory_id: "",
                quantity_used: String(calculatedQty),
                unit_id: String(item.unit_id),
                ui_warehouse_id: "",
                ui_product_id: String(item.product_id),
                ui_product_name: item.product_name,
                ui_batch_number: "",
                ui_available_qty: 0,
                ui_input_quantity: String(calculatedQty),
                ui_selected_unit: 'base',
                ui_base_unit_name: item.unit_name,
                ui_base_unit_id: item.unit_id,
                ui_conversion_rate: 1,
            };
        });
        setBomItems(newBomItems);

        toast.success(`已自動載入配方: ${recipe.name}`, {
            description: `標準產量: ${yieldQty} 份`
        });
    };

    // 當手動切換配方時
    useEffect(() => {
        if (!selectedRecipeId) return;
        const targetRecipe = recipes.find(r => String(r.id) === selectedRecipeId);
        if (targetRecipe) {
            applyRecipe(targetRecipe);
        }
    }, [selectedRecipeId]);

    // 自動產生成品批號與載入配方
    useEffect(() => {
        if (!data.product_id) return;

        // 2. 自動載入配方列表
        const fetchRecipes = async () => {
            try {
                // 改為抓取所有配方
                const res = await fetch(route('api.production.recipes.by-product', data.product_id));
                const recipesData = await res.json();

                if (Array.isArray(recipesData) && recipesData.length > 0) {
                    setRecipes(recipesData);
                    // 預設選取最新的 (第一個)
                    const latest = recipesData[0];
                    setSelectedRecipeId(String(latest.id));
                } else {
                    // 若無配方
                    setRecipes([]);
                    setSelectedRecipeId("");
                    setBomItems([]); // 清空 BOM
                }
            } catch (e) {
                console.error("Failed to fetch recipes", e);
                setRecipes([]);
                setBomItems([]);
            }
        };
        fetchRecipes();
    }, [data.product_id]);

    // 當生產數量變動時，如果是從配方載入的，則按比例更新用量
    useEffect(() => {
        if (bomItems.length > 0 && data.output_quantity) {
            // 這個部位比較複雜，因為使用者可能已經手動修改過或是選了批號
            // 目前先保持簡單：如果使用者改了產出量，我們不強行覆蓋已經選好批號的明細，避免困擾
            // 但如果是剛載入（inventory_id 為空），可以考慮連動？暫時先不處理以維護操作穩定性
        }
    }, [data.output_quantity]);

    // 提交表單
    const submit = (status: 'draft' | 'completed') => {
        // 驗證（簡單前端驗證，完整驗證在後端）
        if (status === 'completed') {
            const missingFields = [];
            if (!data.product_id) missingFields.push('成品商品');
            if (!data.output_quantity) missingFields.push('生產數量');
            if (!selectedWarehouse) missingFields.push('預計入庫倉庫');
            if (bomItems.length === 0) missingFields.push('原物料明細');

            if (missingFields.length > 0) {
                toast.error("請填寫必要欄位", {
                    description: `缺漏：${missingFields.join('、')}`
                });
                return;
            }
        }

        // 轉換 BOM items 格式
        const formattedItems = bomItems
            .filter(item => status === 'draft' || (item.inventory_id && item.quantity_used))
            .map(item => ({
                inventory_id: item.inventory_id ? parseInt(item.inventory_id) : null,
                quantity_used: item.quantity_used ? parseFloat(item.quantity_used) : 0,
                unit_id: item.unit_id ? parseInt(item.unit_id) : null,
            }));

        // 使用 router.post 提交完整資料
        router.post(route('production-orders.store'), {
            ...data,
            warehouse_id: selectedWarehouse ? parseInt(selectedWarehouse) : null,
            items: formattedItems,
            status: status,
        }, {
            onError: (errors) => {
                const errorCount = Object.keys(errors).length;
                toast.error("建立失敗，請檢查表單", {
                    description: `共有 ${errorCount} 個欄位有誤，請修正後再試`
                });
            }
        });
    };

    const handleSubmit = (e: React.FormEvent) => {
        e.preventDefault();
        submit('completed');
    };

    return (
        <AuthenticatedLayout breadcrumbs={getBreadcrumbs("productionOrdersCreate")}>
            <Head title="建立生產單" />

            <div className="container mx-auto p-6 max-w-7xl">
                <div className="mb-6">
                    <Link href={route('production-orders.index')}>
                        <Button
                            variant="outline"
                            className="gap-2 button-outlined-primary mb-6"
                        >
                            <ArrowLeft className="h-4 w-4" />
                            返回生產單
                        </Button>
                    </Link>

                    <div className="flex items-center justify-between">
                        <div>
                            <h1 className="text-2xl font-bold text-grey-0 flex items-center gap-2">
                                <Factory className="h-6 w-6 text-primary-main" />
                                建立生產工單
                            </h1>
                            <p className="text-gray-500 mt-1">
                                建立新的生產排程，選擇原物料並記錄產出
                            </p>
                        </div>
                        <Button
                            onClick={() => submit('draft')}
                            disabled={processing}
                            className="gap-2 button-filled-primary"
                        >
                            <Save className="h-4 w-4" />
                            儲存工單 (草稿)
                        </Button>
                    </div>
                </div>

                <form onSubmit={handleSubmit} className="space-y-6">
                    {/* 成品資訊 */}
                    <div className="bg-white p-6 rounded-lg shadow-sm border border-gray-200 mb-6">
                        <h2 className="text-lg font-semibold mb-4">成品資訊</h2>
                        <div className="grid grid-cols-1 md:grid-cols-2 gap-4">
                            <div className="space-y-1">
                                <Label className="text-xs font-medium text-grey-2">成品商品 *</Label>
                                <SearchableSelect
                                    value={data.product_id}
                                    onValueChange={(v) => setData('product_id', v)}
                                    options={products.map(p => ({
                                        label: `${p.name} (${p.code})`,
                                        value: String(p.id),
                                    }))}
                                    placeholder="選擇成品"
                                    className="w-full h-9"
                                />
                                {errors.product_id && <p className="text-red-500 text-xs mt-1">{errors.product_id}</p>}

                                {/* 配方選擇 (放在成品商品底下) */}
                                {recipes.length > 0 && (
                                    <div className="pt-2">
                                        <div className="flex justify-between items-center mb-1">
                                            <Label className="text-xs font-medium text-grey-2">使用配方</Label>
                                            <span className="text-[10px] text-blue-500">
                                                切換將重置明細
                                            </span>
                                        </div>
                                        <SearchableSelect
                                            value={selectedRecipeId}
                                            onValueChange={setSelectedRecipeId}
                                            options={recipes.map(r => ({
                                                label: `${r.name} (${r.code})`,
                                                value: String(r.id),
                                            }))}
                                            placeholder="選擇配方"
                                            className="w-full h-9"
                                        />
                                    </div>
                                )}
                            </div>

                            <div className="space-y-1">
                                <Label className="text-xs font-medium text-grey-2">生產數量 *</Label>
                                <Input
                                    type="number"
                                    step="any"
                                    value={Number(data.output_quantity) === 0 ? '' : formatQuantity(data.output_quantity)}
                                    onChange={(e) => setData('output_quantity', e.target.value)}
                                    placeholder="例如: 50"
                                    className="h-9 font-mono"
                                />
                                {errors.output_quantity && <p className="text-red-500 text-xs mt-1">{errors.output_quantity}</p>}
                            </div>

                            <div className="space-y-1">
                                <Label className="text-xs font-medium text-grey-2">預計入庫倉庫 *</Label>
                                <SearchableSelect
                                    value={selectedWarehouse}
                                    onValueChange={setSelectedWarehouse}
                                    options={warehouses.map(w => ({
                                        label: w.name,
                                        value: String(w.id),
                                    }))}
                                    placeholder="選擇倉庫"
                                    className="w-full h-9"
                                />
                                {errors.warehouse_id && <p className="text-red-500 text-xs mt-1">{errors.warehouse_id}</p>}
                            </div>
                        </div>

                        <div className="mt-4 space-y-1">
                            <Label className="text-xs font-medium text-grey-2">備註</Label>
                            <Textarea
                                value={data.remark}
                                onChange={(e) => setData('remark', e.target.value)}
                                placeholder="生產備註..."
                                rows={2}
                                className="resize-none"
                            />
                        </div>
                    </div>

                    {/* BOM 原物料明細 */}
                    <div className="bg-white p-6 rounded-lg shadow-sm border border-gray-200 mb-6">
                        <div className="flex items-center justify-between mb-4">
                            <h2 className="text-lg font-semibold">原物料使用明細 (BOM)</h2>
                            <Button
                                type="button"
                                variant="outline"
                                onClick={addBomItem}
                                className="gap-2 button-filled-primary text-white"
                            >
                                <Plus className="h-4 w-4" />
                                新增原物料
                            </Button>
                        </div>

                        {bomItems.length === 0 && (
                            <div className="text-center py-8 text-gray-500">
                                <Factory className="h-8 w-8 mx-auto mb-2 text-gray-300" />
                                點擊「新增原物料」開始建立 BOM
                            </div>
                        )}

                        {bomItems.length > 0 && (
                            <div className="border rounded-lg overflow-hidden">
                                <Table>
                                    <TableHeader>
                                        <TableRow className="bg-gray-50/50">
                                            <TableHead className="w-[18%]">商品 <span className="text-red-500">*</span></TableHead>
                                            <TableHead className="w-[15%]">來源倉庫 <span className="text-red-500">*</span></TableHead>
                                            <TableHead className="w-[30%]">批號 <span className="text-red-500">*</span></TableHead>
                                            <TableHead className="w-[12%]">數量 <span className="text-red-500">*</span></TableHead>
                                            <TableHead className="w-[10%]">單位</TableHead>
                                            <TableHead className="w-[10%]"></TableHead>
                                        </TableRow>
                                    </TableHeader>
                                    <TableBody>
                                        {bomItems.map((item, index) => {
                                            // 1. 商品選項
                                            const productOptions = products.map(p => ({
                                                label: `${p.name} (${p.code})`,
                                                value: String(p.id)
                                            }));

                                            // 2. 來源倉庫選項 (根據商品庫存過濾)
                                            const currentInventories = productInventoryMap[item.ui_product_id] || [];
                                            const filteredWarehouseOptions = Array.from(new Map(
                                                currentInventories.map((inv: InventoryOption) => [inv.warehouse_id, { label: inv.warehouse_name, value: String(inv.warehouse_id) }])
                                            ).values());

                                            // 如果篩選後沒有倉庫（即該商品無庫存），則顯示所有倉庫以供選取（或顯示無庫存提示）
                                            const uniqueWarehouseOptions = filteredWarehouseOptions.length > 0
                                                ? filteredWarehouseOptions
                                                : (item.ui_product_id && !loadingProducts[item.ui_product_id] ? [] : []);

                                            // 3. 批號選項 (利用 sublabel 顯示詳細資訊，保持選中後簡潔)
                                            const batchOptions = currentInventories
                                                .filter((inv: InventoryOption) => String(inv.warehouse_id) === item.ui_warehouse_id)
                                                .map((inv: InventoryOption) => ({
                                                    label: inv.batch_number,
                                                    value: String(inv.id),
                                                    sublabel: `(存:${inv.quantity} | 效:${inv.expiry_date || '無'})`
                                                }));

                                            return (
                                                <TableRow key={index}>
                                                    {/* 1. 選擇商品 */}
                                                    <TableCell className="align-top">
                                                        <SearchableSelect
                                                            value={item.ui_product_id}
                                                            onValueChange={(v) => updateBomItem(index, 'ui_product_id', v)}
                                                            options={productOptions}
                                                            placeholder="選擇商品"
                                                            className="w-full"
                                                        />
                                                    </TableCell>

                                                    {/* 2. 選擇來源倉庫 */}
                                                    <TableCell className="align-top">
                                                        <SearchableSelect
                                                            value={item.ui_warehouse_id}
                                                            onValueChange={(v) => updateBomItem(index, 'ui_warehouse_id', v)}
                                                            options={uniqueWarehouseOptions as any}
                                                            placeholder={item.ui_product_id
                                                                ? (loadingProducts[item.ui_product_id]
                                                                    ? "載入庫存中..."
                                                                    : (uniqueWarehouseOptions.length === 0 ? "該商品目前無庫存" : "選擇倉庫"))
                                                                : "請先選商品"}
                                                            className="w-full"
                                                            disabled={!item.ui_product_id || (loadingProducts[item.ui_product_id])}
                                                        />
                                                    </TableCell>

                                                    {/* 3. 選擇批號 */}
                                                    <TableCell className="align-top">
                                                        <SearchableSelect
                                                            value={item.inventory_id}
                                                            onValueChange={(v) => updateBomItem(index, 'inventory_id', v)}
                                                            options={batchOptions as any}
                                                            placeholder={item.ui_warehouse_id ? "選擇批號" : "請先選倉庫"}
                                                            className="w-full"
                                                            disabled={!item.ui_warehouse_id}
                                                        />
                                                        {item.inventory_id && (() => {
                                                            const selectedInv = currentInventories.find((i: InventoryOption) => String(i.id) === item.inventory_id);
                                                            if (selectedInv) {
                                                                const isInsufficient = selectedInv.quantity < parseFloat(item.ui_input_quantity || '0');
                                                                return (
                                                                    <div className={`text-xs mt-1 ${isInsufficient ? 'text-red-500 font-bold animate-pulse' : 'text-gray-500'}`}>
                                                                        有效日期: {selectedInv.expiry_date || '無'} |
                                                                        庫存: {formatQuantity(selectedInv.quantity)}
                                                                        {isInsufficient && ' (庫存不足！)'}
                                                                    </div>
                                                                );
                                                            }
                                                            return null;
                                                        })()}
                                                    </TableCell>

                                                    {/* 3. 輸入數量 */}
                                                    <TableCell className="align-top">
                                                        <Input
                                                            type="number"
                                                            step="any"
                                                            value={formatQuantity(item.ui_input_quantity)}
                                                            onChange={(e) => updateBomItem(index, 'ui_input_quantity', e.target.value)}
                                                            placeholder="0"
                                                            className="h-9 text-right"
                                                            disabled={!item.inventory_id}
                                                        />
                                                    </TableCell>

                                                    {/* 4. 單位 */}
                                                    <TableCell className="align-top">
                                                        <div className="h-9 flex items-center px-1 text-sm text-gray-600 font-medium">
                                                            {item.ui_base_unit_name || '-'}
                                                        </div>
                                                    </TableCell>


                                                    <TableCell className="align-top">
                                                        <Button
                                                            type="button"
                                                            variant="outline"
                                                            size="sm"
                                                            onClick={() => removeBomItem(index)}
                                                            className="button-outlined-error"
                                                            title="刪除"
                                                        >
                                                            <Trash2 className="h-4 w-4" />
                                                        </Button>
                                                    </TableCell>
                                                </TableRow>
                                            );
                                        })}
                                    </TableBody>
                                </Table>
                            </div>
                        )}

                        {errors.items && <p className="text-red-500 text-sm mt-2">{errors.items}</p>}
                    </div>
                </form>
            </div>
        </AuthenticatedLayout>
    );
}