import { useState, useEffect } from "react";
import { useForm } from "@inertiajs/react";
import {
    Dialog,
    DialogContent,
    DialogDescription,
    DialogFooter,
    DialogHeader,
    DialogTitle,
} from "@/Components/ui/dialog";
import { Button } from "@/Components/ui/button";
import { Input } from "@/Components/ui/input";
import { Label } from "@/Components/ui/label";
import { Textarea } from "@/Components/ui/textarea";
import {
    Select,
    SelectContent,
    SelectItem,
    SelectTrigger,
    SelectValue,
} from "@/Components/ui/select";
import { WarehouseInventory } from "@/types/warehouse";
import { toast } from "sonner";
import { Minus, Plus, Equal } from "lucide-react";

interface InventoryAdjustmentDialogProps {
    warehouseId: string;
    item: WarehouseInventory | null;
    isOpen: boolean;
    onClose: () => void;
}

type Operation = "add" | "subtract" | "set";

export default function InventoryAdjustmentDialog({
    warehouseId,
    item,
    isOpen,
    onClose,
}: InventoryAdjustmentDialogProps) {
    const [operation, setOperation] = useState<Operation>("add");

    const { data, setData, put, processing, reset, errors } = useForm({
        quantity: 0,
        reason: "盤點調整",
        notes: "",
        operation: "add" as Operation,
        type: "adjustment", // 預設類型
    });

    // 重新開放時重置
    useEffect(() => {
        if (isOpen) {
            reset();
            setOperation("add");
        }
    }, [isOpen]);

    useEffect(() => {
        setData("operation", operation);
    }, [operation]);

    const handleSubmit = (e: React.FormEvent) => {
        e.preventDefault();
        if (!item) return;

        put(route("warehouses.inventory.update", {
            warehouse: warehouseId,
            product: item.productId // 這裡後端接收 product (或可用 inventory ID 擴充)
        }), {
            onSuccess: () => {
                onClose();
            },
            onError: () => {
                toast.error("調整失敗，請檢查欄位資料");
            }
        });
    };

    if (!item) return null;

    // 計算剩餘庫存預覽
    const getResultQuantity = () => {
        const inputQty = Number(data.quantity) || 0;
        switch (operation) {
            case "add": return item.quantity + inputQty;
            case "subtract": return Math.max(0, item.quantity - inputQty);
            case "set": return inputQty;
            default: return item.quantity;
        }
    };

    return (
        <Dialog open={isOpen} onOpenChange={onClose}>
            <DialogContent className="sm:max-w-[425px]">
                <DialogHeader>
                    <DialogTitle>手動庫存調整</DialogTitle>
                    <DialogDescription>
                        調整商品：{item.productName} (批號: {item.batchNumber || "無"})
                    </DialogDescription>
                </DialogHeader>

                <form onSubmit={handleSubmit} className="space-y-6 py-4">
                    {/* 現有庫存 */}
                    <div className="flex items-center justify-between p-3 bg-gray-50 rounded-lg border">
                        <span className="text-gray-600">現有庫存</span>
                        <span className="font-bold text-lg">{item.quantity}</span>
                    </div>

                    {/* 調整方式 */}
                    <div className="space-y-3">
                        <Label>調整方式</Label>
                        <div className="grid grid-cols-3 gap-2">
                            <Button
                                type="button"
                                variant={operation === "add" ? "default" : "outline"}
                                className={`flex flex-col gap-1 h-auto py-2 ${operation === "add" ? "bg-primary text-white" : ""}`}
                                onClick={() => setOperation("add")}
                            >
                                <Plus className="h-4 w-4" />
                                <span className="text-xs">增加</span>
                            </Button>
                            <Button
                                type="button"
                                variant={operation === "subtract" ? "default" : "outline"}
                                className={`flex flex-col gap-1 h-auto py-2 ${operation === "subtract" ? "bg-primary text-white" : ""}`}
                                onClick={() => setOperation("subtract")}
                            >
                                <Minus className="h-4 w-4" />
                                <span className="text-xs">減少</span>
                            </Button>
                            <Button
                                type="button"
                                variant={operation === "set" ? "default" : "outline"}
                                className={`flex flex-col gap-1 h-auto py-2 ${operation === "set" ? "bg-primary text-white" : ""}`}
                                onClick={() => setOperation("set")}
                            >
                                <Equal className="h-4 w-4" />
                                <span className="text-xs">直接設定</span>
                            </Button>
                        </div>
                    </div>

                    {/* 調整數量 */}
                    <div className="space-y-2">
                        <Label htmlFor="quantity">調整數量</Label>
                        <Input
                            id="quantity"
                            type="number"
                            step="any"
                            value={data.quantity === 0 ? "" : data.quantity}
                            onChange={e => setData("quantity", Number(e.target.value))}
                            placeholder="請輸入數量"
                            className={errors.quantity ? "border-red-500" : ""}
                        />
                        {errors.quantity && <p className="text-xs text-red-500">{errors.quantity}</p>}
                    </div>

                    {/* 預計剩餘庫存 */}
                    <div className="flex items-center justify-between p-3 bg-primary/5 rounded-lg border border-primary/20">
                        <span className="text-gray-600">調整後庫存</span>
                        <span className="font-bold text-lg text-primary">{getResultQuantity()}</span>
                    </div>

                    {/* 調整原因 */}
                    <div className="space-y-2">
                        <Label htmlFor="reason">調整原因</Label>
                        <Select
                            value={data.reason}
                            onValueChange={val => setData("reason", val)}
                        >
                            <SelectTrigger>
                                <SelectValue placeholder="選擇原因" />
                            </SelectTrigger>
                            <SelectContent>
                                <SelectItem value="盤點調整">盤點調整</SelectItem>
                                <SelectItem value="損耗">損耗</SelectItem>
                                <SelectItem value="其他">其他</SelectItem>
                            </SelectContent>
                        </Select>
                    </div>

                    {/* 備註 */}
                    <div className="space-y-2">
                        <Label htmlFor="notes">備註（選填）</Label>
                        <Textarea
                            id="notes"
                            value={data.notes}
                            onChange={e => setData("notes", e.target.value)}
                            placeholder="輸入調整細節..."
                            rows={2}
                        />
                    </div>

                    <DialogFooter>
                        <Button
                            type="button"
                            variant="outline"
                            onClick={onClose}
                            disabled={processing}
                        >
                            取消
                        </Button>
                        <Button
                            type="submit"
                            disabled={processing || data.quantity <= 0 && operation !== "set"}
                        >
                            確認調整
                        </Button>
                    </DialogFooter>
                </form>
            </DialogContent>
        </Dialog>
    );
}

// Helper: 假如沒有 route 函式 (Ziggy)，則需要手動處理 URL
function route(name: string, params: any) {
    if (name === "warehouses.inventory.update") {
        return `/warehouses/${params.warehouse}/inventory/${params.product}`;
    }
    return "";
}