/**
 * 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 { Factory, Plus, Trash2, ArrowLeft, Save, Calendar, AlertCircle } from 'lucide-react';
import { Button } from "@/Components/ui/button";
import AuthenticatedLayout from "@/Layouts/AuthenticatedLayout";
import { Head, router, useForm } from "@inertiajs/react";
import toast, { Toaster } from 'react-hot-toast';
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 { Link } from "@inertiajs/react";
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 Unit {
    id: number;
    name: string;
}

interface InventoryOption {
    id: number;
    product_id: number;
    product_name: string;
    product_code: 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[];
    units: Unit[];
}

export default function ProductionCreate({ products, warehouses }: Props) {
    const [selectedWarehouse, setSelectedWarehouse] = useState<string>(""); // 產出倉庫
    // 快取對照表：warehouse_id -> inventories
    const [inventoryMap, setInventoryMap] = useState<Record<string, InventoryOption[]>>({});
    const [loadingWarehouses, setLoadingWareStates] = useState<Record<string, boolean>>({});

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

    const { data, setData, processing, errors } = useForm({
        product_id: "",
        warehouse_id: "",
        output_quantity: "",
        output_batch_number: "",
        output_box_count: "",
        production_date: new Date().toISOString().split('T')[0],
        expiry_date: "",
        remark: "",
        items: [] as { inventory_id: number; quantity_used: number; unit_id: number | null }[],
    });

    // 獲取倉庫資料的輔助函式
    const fetchWarehouseInventory = async (warehouseId: string) => {
        if (!warehouseId || inventoryMap[warehouseId] || loadingWarehouses[warehouseId]) return;

        setLoadingWareStates(prev => ({ ...prev, [warehouseId]: true }));
        try {
            const res = await fetch(route('api.production.warehouses.inventories', warehouseId));
            const data = await res.json();
            setInventoryMap(prev => ({ ...prev, [warehouseId]: data }));
        } catch (e) {
            console.error(e);
        } finally {
            setLoadingWareStates(prev => ({ ...prev, [warehouseId]: 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 };

        // 0. 當選擇來源倉庫變更時
        if (field === 'ui_warehouse_id') {
            // 重置後續欄位
            item.ui_product_id = "";
            item.inventory_id = "";
            item.quantity_used = "";
            item.unit_id = "";
            item.ui_input_quantity = "";
            item.ui_selected_unit = "base";
            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;

            // 觸發載入資料
            if (value) {
                fetchWarehouseInventory(value);
            }
        }

        // 1. 當選擇商品變更時 -> 清空批號與相關資訊
        if (field === 'ui_product_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;
        }

        // 2. 當選擇批號 (Inventory ID) 變更時 -> 載入該批號資訊
        if (field === 'inventory_id' && value) {
            const currentOptions = inventoryMap[item.ui_warehouse_id] || [];
            const inv = currentOptions.find(i => String(i.id) === value);
            if (inv) {
                item.ui_product_id = String(inv.product_id); // 確保商品也被選中 (雖通常是先選商品)
                item.ui_product_name = inv.product_name;
                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.base_unit_name || inv.unit_name || '';
                item.ui_large_unit_name = inv.large_unit_name || '';
                item.ui_base_unit_id = inv.base_unit_id;
                item.ui_large_unit_id = inv.large_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 || '');
            }
        }

        // 3. 計算最終數量 (Base Quantity)
        // 當 輸入數量 或 選擇單位 變更時
        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);
                // 注意：後端需要的是 Base Unit ID? 這裡我們都送 Base Unit ID，因為 quantity_used 是 Base Unit
                // 但為了保留 User 的選擇，我們可能可以在 remark 註記? 目前先從簡
                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]);

    // 自動產生成品批號（當選擇商品或日期變動時）
    useEffect(() => {
        if (!data.product_id) return;

        const product = products.find(p => String(p.id) === data.product_id);
        if (!product) return;

        const datePart = data.production_date; // YYYY-MM-DD
        const dateFormatted = datePart.replace(/-/g, '');
        const originCountry = 'TW';

        // 呼叫 API 取得下一組流水號
        // 複用庫存批號 API，但這裡可能沒有選 warehouse，所以用第一個預設
        const warehouseId = selectedWarehouse || (warehouses.length > 0 ? String(warehouses[0].id) : '1');

        fetch(`/api/warehouses/${warehouseId}/inventory/batches/${product.id}?originCountry=${originCountry}&arrivalDate=${datePart}`)
            .then(res => res.json())
            .then(result => {
                const seq = result.nextSequence || '01';
                const suggested = `${product.code}-${originCountry}-${dateFormatted}-${seq}`;
                setData('output_batch_number', suggested);
            })
            .catch(() => {
                // Fallback：若 API 失敗，使用預設 01
                const suggested = `${product.code}-${originCountry}-${dateFormatted}-01`;
                setData('output_batch_number', suggested);
            });
    }, [data.product_id, data.production_date]);

    // 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 (!data.output_batch_number) missingFields.push('成品批號');
            if (!data.production_date) missingFields.push('生產日期');
            if (!selectedWarehouse) missingFields.push('入庫倉庫');
            if (bomItems.length === 0) missingFields.push('原物料明細');

            if (missingFields.length > 0) {
                toast.error(
                    <div className="flex flex-col gap-1">
                        <span className="font-bold">請填寫必要欄位</span>
                        <span className="text-sm">缺漏：{missingFields.join('、')}</span>
                    </div>
                );
                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,
            items: formattedItems,
            status: status,
        }, {
            onError: (errors) => {
                const errorCount = Object.keys(errors).length;
                toast.error(
                    <div className="flex flex-col gap-1">
                        <span className="font-bold">建立失敗，請檢查表單</span>
                        <span className="text-sm">共有 {errorCount} 個欄位有誤，請修正後再試</span>
                    </div>
                );
            }
        });
    };

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

    return (
        <AuthenticatedLayout breadcrumbs={getBreadcrumbs("productionOrdersCreate")}>
            <Head title="建立生產單" />
            <Toaster position="top-right" />
            <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>
                        <div className="flex gap-2">
                            <Button
                                onClick={() => submit('draft')}
                                disabled={processing}
                                variant="outline"
                                className="button-outlined-primary"
                            >
                                <Save className="mr-2 h-4 w-4" />
                                儲存草稿
                            </Button>
                            <Button
                                onClick={() => submit('completed')}
                                disabled={processing}
                                className="button-filled-primary"
                            >
                                <Factory className="mr-2 h-4 w-4" />
                                建立工單
                            </Button>
                        </div>
                    </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>}
                            </div>

                            <div className="space-y-1">
                                <Label className="text-xs font-medium text-grey-2">生產數量 *</Label>
                                <Input
                                    type="number"
                                    step="0.01"
                                    value={data.output_quantity}
                                    onChange={(e) => setData('output_quantity', e.target.value)}
                                    placeholder="例如: 50"
                                    className="h-9"
                                />
                                {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">成品批號 *</Label>
                                <Input
                                    value={data.output_batch_number}
                                    onChange={(e) => setData('output_batch_number', e.target.value)}
                                    placeholder="選擇商品後自動產生"
                                    className="h-9 font-mono"
                                />
                                {errors.output_batch_number && <p className="text-red-500 text-xs mt-1">{errors.output_batch_number}</p>}
                            </div>

                            <div className="space-y-1">
                                <Label className="text-xs font-medium text-grey-2">箱數（選填）</Label>
                                <Input
                                    value={data.output_box_count}
                                    onChange={(e) => setData('output_box_count', e.target.value)}
                                    placeholder="例如: 10"
                                    className="h-9"
                                />
                            </div>

                            <div className="space-y-1">
                                <Label className="text-xs font-medium text-grey-2">生產日期 *</Label>
                                <div className="relative">
                                    <Calendar className="absolute left-2.5 top-1/2 transform -translate-y-1/2 h-4 w-4 text-gray-400 pointer-events-none" />
                                    <Input
                                        type="date"
                                        value={data.production_date}
                                        onChange={(e) => setData('production_date', e.target.value)}
                                        className="h-9 pl-9"
                                    />
                                </div>
                                {errors.production_date && <p className="text-red-500 text-xs mt-1">{errors.production_date}</p>}
                            </div>

                            <div className="space-y-1">
                                <Label className="text-xs font-medium text-grey-2">成品效期（選填）</Label>
                                <div className="relative">
                                    <Calendar className="absolute left-2.5 top-1/2 transform -translate-y-1/2 h-4 w-4 text-gray-400 pointer-events-none" />
                                    <Input
                                        type="date"
                                        value={data.expiry_date}
                                        onChange={(e) => setData('expiry_date', e.target.value)}
                                        className="h-9 pl-9"
                                    />
                                </div>
                            </div>

                            <div className="space-y-1">
                                <Label className="text-xs font-medium text-grey-2">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-[20%]">來源倉庫 <span className="text-red-500">*</span></TableHead>
                                            <TableHead className="w-[20%]">商品 <span className="text-red-500">*</span></TableHead>
                                            <TableHead className="w-[25%]">批號 <span className="text-red-500">*</span></TableHead>
                                            <TableHead className="w-[15%]">數量 <span className="text-red-500">*</span></TableHead>
                                            <TableHead className="w-[15%]">單位</TableHead>
                                            <TableHead className="w-[5%]"></TableHead>
                                        </TableRow>
                                    </TableHeader>
                                    <TableBody>
                                        {bomItems.map((item, index) => {
                                            // 取得此列已載入的 Inventory Options
                                            const currentOptions = inventoryMap[item.ui_warehouse_id] || [];

                                            // 過濾商品
                                            const uniqueProductOptions = Array.from(new Map(
                                                currentOptions.map(inv => [inv.product_id, { label: inv.product_name, value: String(inv.product_id) }])
                                            ).values());

                                            // 過濾批號
                                            const batchOptions = currentOptions
                                                .filter(inv => String(inv.product_id) === item.ui_product_id)
                                                .map(inv => ({
                                                    label: `${inv.batch_number} / ${inv.expiry_date || '無效期'} / ${inv.quantity}`,
                                                    value: String(inv.id)
                                                }));



                                            return (
                                                <TableRow key={index}>
                                                    {/* 0. 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={warehouses.map(w => ({ label: w.name, value: String(w.id) }))}
                                                            placeholder="選擇倉庫"
                                                            className="w-full"
                                                        />
                                                    </TableCell>

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

                                                    {/* 2. 選擇批號 */}
                                                    <TableCell className="align-top">
                                                        <SearchableSelect
                                                            value={item.inventory_id}
                                                            onValueChange={(v) => updateBomItem(index, 'inventory_id', v)}
                                                            options={batchOptions}
                                                            placeholder={item.ui_product_id ? "選擇批號" : "請先選商品"}
                                                            className="w-full"
                                                            disabled={!item.ui_product_id}
                                                        />
                                                        {item.inventory_id && (() => {
                                                            const selectedInv = currentOptions.find(i => String(i.id) === item.inventory_id);
                                                            if (selectedInv) return (
                                                                <div className="text-xs text-gray-500 mt-1">
                                                                    有效日期: {selectedInv.expiry_date || '無'} | 庫存: {selectedInv.quantity}
                                                                </div>
                                                            );
                                                            return null;
                                                        })()}
                                                    </TableCell>

                                                    {/* 3. 輸入數量 */}
                                                    <TableCell className="align-top">
                                                        <Input
                                                            type="number"
                                                            step="1"
                                                            value={item.ui_input_quantity}
                                                            onChange={(e) => updateBomItem(index, 'ui_input_quantity', e.target.value)}
                                                            placeholder="0"
                                                            className="h-9"
                                                            disabled={!item.inventory_id}
                                                        />
                                                    </TableCell>

                                                    {/* 4. 選擇單位 */}
                                                    <TableCell className="align-top pt-3">
                                                        <span className="text-sm">{item.ui_base_unit_name}</span>
                                                    </TableCell>



                                                    <TableCell className="align-top">
                                                        <Button
                                                            type="button"
                                                            variant="ghost"
                                                            size="sm"
                                                            onClick={() => removeBomItem(index)}
                                                            className="text-red-500 hover:text-red-700 hover:bg-red-50 p-2"
                                                        >
                                                            <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>
    );
}