import { useState, useEffect } from "react";
import AuthenticatedLayout from "@/Layouts/AuthenticatedLayout";
import { Head, router, Link } from "@inertiajs/react";
import { Button } from "@/Components/ui/button";
import { Input } from "@/Components/ui/input";
import { Label } from "@/Components/ui/label";
import {
    Table,
    TableBody,
    TableCell,
    TableHead,
    TableHeader,
    TableRow,
} from "@/Components/ui/table";
import { Badge } from "@/Components/ui/badge";
import { Checkbox } from "@/Components/ui/checkbox";
import {
    Dialog,
    DialogContent,
    DialogHeader,
    DialogTitle,
    DialogTrigger,
} from "@/Components/ui/dialog";
import {
    AlertDialog,
    AlertDialogAction,
    AlertDialogCancel,
    AlertDialogContent,
    AlertDialogDescription,
    AlertDialogFooter,
    AlertDialogHeader,
    AlertDialogTitle,
    AlertDialogTrigger,
} from "@/Components/ui/alert-dialog";
import { Plus, Save, Trash2, ArrowLeft, CheckCircle, Package, ArrowLeftRight, Printer, Search } from "lucide-react";
import { toast } from "sonner";
import axios from "axios";
import { Can } from '@/Components/Permission/Can';
import { usePermission } from '@/hooks/usePermission';

export default function Show({ order }: any) {
    const { can } = usePermission();
    const [items, setItems] = useState(order.items || []);
    const [remarks, setRemarks] = useState(order.remarks || "");
    const [isSaving, setIsSaving] = useState(false);
    const [deleteId, setDeleteId] = useState<string | null>(null);
    const [isPostDialogOpen, setIsPostDialogOpen] = useState(false);

    // Product Selection
    const [isProductDialogOpen, setIsProductDialogOpen] = useState(false);
    const [availableInventory, setAvailableInventory] = useState<any[]>([]);
    const [loadingInventory, setLoadingInventory] = useState(false);
    const [searchQuery, setSearchQuery] = useState('');
    const [selectedInventory, setSelectedInventory] = useState<string[]>([]); // product_id-batch

    useEffect(() => {
        if (isProductDialogOpen) {
            loadInventory();
            setSelectedInventory([]);
            setSearchQuery('');
        }
    }, [isProductDialogOpen]);

    const loadInventory = async () => {
        setLoadingInventory(true);
        try {
            // Fetch inventory from SOURCE warehouse
            const response = await axios.get(route('api.warehouses.inventories', order.from_warehouse_id));
            setAvailableInventory(response.data);
        } catch (error) {
            console.error("Failed to load inventory", error);
            toast.error("無法載入庫存資料");
        } finally {
            setLoadingInventory(false);
        }
    };

    const toggleSelect = (key: string) => {
        setSelectedInventory(prev =>
            prev.includes(key) ? prev.filter(k => k !== key) : [...prev, key]
        );
    };

    const toggleSelectAll = () => {
        const filtered = availableInventory.filter(inv =>
            inv.product_name.toLowerCase().includes(searchQuery.toLowerCase()) ||
            inv.product_code.toLowerCase().includes(searchQuery.toLowerCase())
        );
        const filteredKeys = filtered.map(inv => `${inv.product_id}-${inv.batch_number}`);

        if (filteredKeys.length > 0 && filteredKeys.every(k => selectedInventory.includes(k))) {
            setSelectedInventory(prev => prev.filter(k => !filteredKeys.includes(k)));
        } else {
            setSelectedInventory(prev => Array.from(new Set([...prev, ...filteredKeys])));
        }
    };

    const handleAddSelected = () => {
        if (selectedInventory.length === 0) return;

        const newItems = [...items];
        let addedCount = 0;

        availableInventory.forEach(inv => {
            const key = `${inv.product_id}-${inv.batch_number}`;
            if (selectedInventory.includes(key)) {
                // Check if already added
                const exists = newItems.find((i: any) =>
                    i.product_id === inv.product_id &&
                    i.batch_number === inv.batch_number
                );

                if (!exists) {
                    newItems.push({
                        product_id: inv.product_id,
                        product_name: inv.product_name,
                        product_code: inv.product_code,
                        batch_number: inv.batch_number,
                        unit: inv.unit_name,
                        quantity: 1, // Default 1
                        max_quantity: inv.quantity, // Max available
                        notes: "",
                    });
                    addedCount++;
                }
            }
        });

        setItems(newItems);
        setIsProductDialogOpen(false);

        if (addedCount > 0) {
            toast.success(`已成功加入 ${addedCount} 個項目`);
        } else {
            toast.info("選取的商品已在清單中");
        }
    };

    const handleUpdateItem = (index: number, field: string, value: any) => {
        const newItems = [...items];
        newItems[index][field] = value;
        setItems(newItems);
    };

    const handleRemoveItem = (index: number) => {
        const newItems = items.filter((_: any, i: number) => i !== index);
        setItems(newItems);
    };

    const handleSave = async () => {
        setIsSaving(true);
        try {
            await router.put(route('inventory.transfer.update', [order.id]), {
                items: items,
                remarks: remarks,
            }, {
                onSuccess: () => { },
                onError: () => toast.error("儲存失敗，請檢查輸入"),
            });
        } finally {
            setIsSaving(false);
        }
    };

    const handlePost = () => {
        router.put(route('inventory.transfer.update', [order.id]), {
            action: 'post'
        }, {
            onSuccess: () => {
                setIsPostDialogOpen(false);
            }
        });
    };

    const handleDelete = () => {
        router.delete(route('inventory.transfer.destroy', [order.id]), {
            onSuccess: () => {
                setDeleteId(null);
            }
        });
    };

    const canEdit = can('inventory_transfer.edit');
    const isReadOnly = order.status !== 'draft' || !canEdit;

    return (
        <AuthenticatedLayout
            breadcrumbs={[
                { label: '商品與庫存管理', href: '#' },
                { label: '庫存調撥', href: route('inventory.transfer.index') },
                { label: `調撥單: ${order.doc_no}`, href: route('inventory.transfer.show', [order.id]), isPage: true },
            ]}
        >
            <Head title={`調撥單 ${order.doc_no}`} />

            <div className="container mx-auto p-6 max-w-7xl animate-in fade-in duration-500 space-y-6">
                <div>
                    <Link href={route('inventory.transfer.index')}>
                        <Button
                            variant="outline"
                            className="gap-2 button-outlined-primary mb-6"
                        >
                            <ArrowLeft className="h-4 w-4" />
                            返回調撥單列表
                        </Button>
                    </Link>

                    <div className="flex flex-col md:flex-row md:items-center justify-between gap-4">
                        <div>
                            <div className="flex items-center gap-2">
                                <h1 className="text-2xl font-bold text-grey-0 flex items-center gap-2">
                                    <ArrowLeftRight className="h-6 w-6 text-primary-main" />
                                    調撥單: {order.doc_no}
                                </h1>
                                {order.status === 'completed' && <Badge className="bg-green-500 hover:bg-green-600">已完成</Badge>}
                                {order.status === 'draft' && <Badge className="bg-blue-500 hover:bg-blue-600">草稿</Badge>}
                                {order.status === 'voided' && <Badge variant="destructive">已作廢</Badge>}
                            </div>
                            <p className="text-sm text-gray-500 mt-1 font-medium">
                                來源: {order.from_warehouse_name} <ArrowLeftRight className="inline-block h-3 w-3 mx-1" /> 目的: {order.to_warehouse_name} <span className="mx-2">|</span> 建立人: {order.created_by}
                            </p>
                        </div>

                        <div className="flex items-center gap-2">
                            <Button
                                variant="outline"
                                size="sm"
                                className="button-outlined-primary"
                                onClick={() => window.print()}
                            >
                                <Printer className="w-4 h-4 mr-2" />
                                列印
                            </Button>

                            {!isReadOnly && (
                                <div className="flex items-center gap-2">
                                    <Can permission="inventory_transfer.delete">
                                        <AlertDialog open={!!deleteId} onOpenChange={(open) => !open && setDeleteId(null)}>
                                            <AlertDialogTrigger asChild>
                                                <Button variant="outline" size="sm" className="button-outlined-error" onClick={() => setDeleteId(order.id)}>
                                                    <Trash2 className="w-4 h-4 mr-2" />
                                                    刪除
                                                </Button>
                                            </AlertDialogTrigger>
                                            <AlertDialogContent>
                                                <AlertDialogHeader>
                                                    <AlertDialogTitle>確定要刪除此調撥單嗎？</AlertDialogTitle>
                                                    <AlertDialogDescription>
                                                        此動作無法復原。如果單據已存在重要資料，請謹慎操作。
                                                    </AlertDialogDescription>
                                                </AlertDialogHeader>
                                                <AlertDialogFooter>
                                                    <AlertDialogCancel>取消</AlertDialogCancel>
                                                    <AlertDialogAction onClick={handleDelete} className="button-filled-error">確認刪除</AlertDialogAction>
                                                </AlertDialogFooter>
                                            </AlertDialogContent>
                                        </AlertDialog>
                                    </Can>

                                    <Can permission="inventory_transfer.edit">
                                        <Button
                                            variant="outline"
                                            size="sm"
                                            className="button-outlined-primary"
                                            onClick={handleSave}
                                            disabled={isSaving}
                                        >
                                            <Save className="w-4 h-4 mr-2" />
                                            儲存草稿
                                        </Button>

                                        <AlertDialog open={isPostDialogOpen} onOpenChange={setIsPostDialogOpen}>
                                            <AlertDialogTrigger asChild>
                                                <Button
                                                    size="sm"
                                                    className="button-filled-primary"
                                                    disabled={items.length === 0 || isSaving}
                                                >
                                                    <CheckCircle className="w-4 h-4 mr-2" />
                                                    確認過帳
                                                </Button>
                                            </AlertDialogTrigger>
                                            <AlertDialogContent>
                                                <AlertDialogHeader>
                                                    <AlertDialogTitle>確定要過帳嗎？</AlertDialogTitle>
                                                    <AlertDialogDescription>
                                                        過帳後庫存將立即從「{order.from_warehouse_name}」轉移至「{order.to_warehouse_name}」，且無法再進行修改。
                                                    </AlertDialogDescription>
                                                </AlertDialogHeader>
                                                <AlertDialogFooter>
                                                    <AlertDialogCancel>取消</AlertDialogCancel>
                                                    <AlertDialogAction onClick={handlePost} className="button-filled-primary">確認過帳</AlertDialogAction>
                                                </AlertDialogFooter>
                                            </AlertDialogContent>
                                        </AlertDialog>
                                    </Can>
                                </div>
                            )}
                        </div>
                    </div>
                </div>

                <div className="bg-white rounded-lg shadow-sm border p-6 space-y-4">
                    <div className="flex items-center justify-between">
                        <Label className="text-gray-500 font-semibold">備註資訊</Label>
                    </div>
                    {isReadOnly ? (
                        <div className="text-gray-700 p-2 bg-gray-50 rounded border text-sm min-h-[40px]">
                            {order.remarks || '無備註'}
                        </div>
                    ) : (
                        <Input
                            value={remarks}
                            onChange={(e) => setRemarks(e.target.value)}
                            className="h-9 focus:ring-primary-main"
                            placeholder="填寫調撥單備註..."
                        />
                    )}
                </div>

                <div className="bg-white rounded-lg shadow-sm border p-6 space-y-4">
                    <div className="flex items-center justify-between">
                        <div>
                            <h3 className="font-semibold text-lg text-grey-900">調撥明細</h3>
                            <p className="text-sm text-grey-500">
                                請選擇要調撥的商品並輸入數量。所有商品將從「{order.from_warehouse_name}」轉出。
                            </p>
                        </div>
                        {!isReadOnly && (
                            <Dialog open={isProductDialogOpen} onOpenChange={setIsProductDialogOpen}>
                                <DialogTrigger asChild>
                                    <Button variant="outline" className="button-outlined-primary">
                                        <Plus className="h-4 w-4 mr-2" />
                                        加入商品
                                    </Button>
                                </DialogTrigger>
                                <DialogContent className="max-w-4xl max-h-[85vh] flex flex-col p-6">
                                    <DialogHeader className="flex flex-row items-center justify-between space-y-0 pb-4">
                                        <DialogTitle className="text-xl">選擇來源庫存 ({order.from_warehouse_name})</DialogTitle>
                                        <div className="relative w-64">
                                            <Search className="absolute left-3 top-1/2 -translate-y-1/2 h-4 w-4 text-grey-3" />
                                            <Input
                                                placeholder="搜尋品名或代號..."
                                                className="pl-9 h-9 border-2 border-grey-3 focus:ring-primary-main"
                                                value={searchQuery}
                                                onChange={(e) => setSearchQuery(e.target.value)}
                                            />
                                        </div>
                                    </DialogHeader>
                                    <div className="flex-1 overflow-auto pr-1">
                                        {loadingInventory ? (
                                            <div className="text-center py-12">
                                                <Package className="h-10 w-10 animate-bounce mx-auto text-gray-300 mb-2" />
                                                <p className="text-grey-2 text-sm">庫存資料載入中...</p>
                                            </div>
                                        ) : (
                                            <div className="border rounded-lg overflow-hidden">
                                                <Table>
                                                    <TableHeader className="bg-gray-50/80 sticky top-0 z-10 shadow-sm">
                                                        <TableRow>
                                                            <TableHead className="w-[50px] text-center">
                                                                <Checkbox
                                                                    checked={availableInventory.length > 0 && (() => {
                                                                        const filtered = availableInventory.filter(inv =>
                                                                            inv.product_name.toLowerCase().includes(searchQuery.toLowerCase()) ||
                                                                            inv.product_code.toLowerCase().includes(searchQuery.toLowerCase())
                                                                        );
                                                                        const filteredKeys = filtered.map(inv => `${inv.product_id}-${inv.batch_number}`);
                                                                        return filteredKeys.length > 0 && filteredKeys.every(k => selectedInventory.includes(k));
                                                                    })()}
                                                                    onCheckedChange={() => toggleSelectAll()}
                                                                />
                                                            </TableHead>
                                                            <TableHead className="font-medium text-grey-600">商品代號</TableHead>
                                                            <TableHead className="font-medium text-grey-600">品名</TableHead>
                                                            <TableHead className="font-medium text-grey-600">批號</TableHead>
                                                            <TableHead className="text-right font-medium text-grey-600 pr-6">現有庫存</TableHead>
                                                        </TableRow>
                                                    </TableHeader>
                                                    <TableBody>
                                                        {(() => {
                                                            const filtered = availableInventory.filter(inv =>
                                                                inv.product_name.toLowerCase().includes(searchQuery.toLowerCase()) ||
                                                                inv.product_code.toLowerCase().includes(searchQuery.toLowerCase())
                                                            );

                                                            if (filtered.length === 0) {
                                                                return (
                                                                    <TableRow>
                                                                        <TableCell colSpan={5} className="text-center py-12 text-grey-3 italic font-medium">
                                                                            {searchQuery ? `找不到與 "${searchQuery}" 相關的商品` : '尚無庫存資料'}
                                                                        </TableCell>
                                                                    </TableRow>
                                                                );
                                                            }

                                                            return filtered.map((inv) => {
                                                                const key = `${inv.product_id}-${inv.batch_number}`;
                                                                const isSelected = selectedInventory.includes(key);
                                                                return (
                                                                    <TableRow
                                                                        key={key}
                                                                        className={`hover:bg-primary-lightest/20 cursor-pointer transition-colors ${isSelected ? 'bg-primary-lightest/40' : ''}`}
                                                                        onClick={() => toggleSelect(key)}
                                                                    >
                                                                        <TableCell className="text-center" onClick={(e) => e.stopPropagation()}>
                                                                            <Checkbox
                                                                                checked={isSelected}
                                                                                onCheckedChange={() => toggleSelect(key)}
                                                                            />
                                                                        </TableCell>
                                                                        <TableCell className="font-mono text-sm text-grey-1">{inv.product_code}</TableCell>
                                                                        <TableCell className="font-semibold text-grey-0">{inv.product_name}</TableCell>
                                                                        <TableCell className="text-sm font-mono text-grey-2">{inv.batch_number || '-'}</TableCell>
                                                                        <TableCell className="text-right font-bold text-primary-main pr-6">{inv.quantity} {inv.unit_name}</TableCell>
                                                                    </TableRow>
                                                                );
                                                            });
                                                        })()}
                                                    </TableBody>
                                                </Table>
                                            </div>
                                        )}
                                    </div>
                                    <div className="mt-6 flex items-center justify-between border-t pt-4">
                                        <div className="flex items-center gap-3">
                                            <div className="px-3 py-1 bg-primary-lightest/50 border border-primary-light/20 rounded-full text-sm font-medium text-primary-main animate-in zoom-in duration-200">
                                                已選取 {selectedInventory.length} 項商品
                                            </div>
                                            {selectedInventory.length > 0 && (
                                                <Button
                                                    variant="ghost"
                                                    size="sm"
                                                    className="text-grey-3 hover:text-red-500 hover:bg-red-50 text-xs px-2 h-7"
                                                    onClick={() => setSelectedInventory([])}
                                                >
                                                    清除全部
                                                </Button>
                                            )}
                                        </div>
                                        <div className="flex gap-2">
                                            <Button
                                                variant="outline"
                                                className="button-outlined-primary w-24"
                                                onClick={() => setIsProductDialogOpen(false)}
                                            >
                                                取消
                                            </Button>
                                            <Button
                                                className="button-filled-primary min-w-32"
                                                disabled={selectedInventory.length === 0}
                                                onClick={handleAddSelected}
                                            >
                                                確認加入選取項
                                            </Button>
                                        </div>
                                    </div>
                                </DialogContent>
                            </Dialog>
                        )}
                    </div>

                    <div className="border rounded-lg overflow-hidden">
                        <Table>
                            <TableHeader className="bg-gray-50">
                                <TableRow>
                                    <TableHead className="w-[50px] text-center font-medium text-grey-600">#</TableHead>
                                    <TableHead className="font-medium text-grey-600">商品名稱 / 代號</TableHead>
                                    <TableHead className="font-medium text-grey-600">批號</TableHead>
                                    <TableHead className="text-right w-32 font-medium text-grey-600">
                                        {order.status === 'completed' ? '過帳時庫存' : '可用庫存'}
                                    </TableHead>
                                    <TableHead className="text-right w-40 font-medium text-grey-600">調撥數量</TableHead>
                                    <TableHead className="font-medium text-grey-600">單位</TableHead>
                                    <TableHead className="font-medium text-grey-600">備註</TableHead>
                                    {!isReadOnly && <TableHead className="w-[50px]"></TableHead>}
                                </TableRow>
                            </TableHeader>
                            <TableBody>
                                {items.length === 0 ? (
                                    <TableRow>
                                        <TableCell colSpan={8} className="text-center h-24 text-gray-500">
                                            尚未加入商品
                                        </TableCell>
                                    </TableRow>
                                ) : (
                                    items.map((item: any, index: number) => (
                                        <TableRow key={index}>
                                            <TableCell className="text-center text-gray-500 font-medium">{index + 1}</TableCell>
                                            <TableCell className="py-3">
                                                <div className="flex flex-col">
                                                    <span className="font-semibold text-gray-900">{item.product_name}</span>
                                                    <span className="text-xs text-gray-500 font-mono">{item.product_code}</span>
                                                </div>
                                            </TableCell>
                                            <TableCell className="text-sm font-mono">{item.batch_number || '-'}</TableCell>
                                            <TableCell className="text-right font-semibold text-primary-main">
                                                {item.max_quantity} {item.unit || item.unit_name}
                                            </TableCell>
                                            <TableCell className="px-1 py-3">
                                                {isReadOnly ? (
                                                    <div className="text-right font-semibold mr-2">{item.quantity}</div>
                                                ) : (
                                                    <div className="flex flex-col gap-1 items-end pr-2">
                                                        <Input
                                                            type="number"
                                                            min="0.01"
                                                            step="0.01"
                                                            value={item.quantity}
                                                            onChange={(e) => handleUpdateItem(index, 'quantity', e.target.value)}
                                                            className="h-9 w-32 text-right font-medium focus:ring-primary-main"
                                                        />
                                                    </div>
                                                )}
                                            </TableCell>
                                            <TableCell className="text-sm text-gray-500">{item.unit || item.unit_name}</TableCell>
                                            <TableCell className="px-1">
                                                {isReadOnly ? (
                                                    <span className="text-sm text-gray-600">{item.notes}</span>
                                                ) : (
                                                    <Input
                                                        value={item.notes}
                                                        onChange={(e) => handleUpdateItem(index, 'notes', e.target.value)}
                                                        placeholder="備註..."
                                                        className="h-9 text-sm"
                                                    />
                                                )}
                                            </TableCell>
                                            {!isReadOnly && (
                                                <TableCell className="text-center">
                                                    <Button variant="ghost" size="sm" className="h-8 w-8 text-red-400 hover:text-red-600 hover:bg-red-50 p-0" onClick={() => handleRemoveItem(index)}>
                                                        <Trash2 className="h-4 w-4" />
                                                    </Button>
                                                </TableCell>
                                            )}
                                        </TableRow>
                                    ))
                                )}
                            </TableBody>
                        </Table>
                    </div>
                </div>
            </div>
        </AuthenticatedLayout>
    );
}