import React, { useState, useEffect, useMemo, useRef } from 'react';
import { Head } from '@inertiajs/react';
import AppLayout from '@/Layouts/AppLayout';
import {
    MaterialReactTable,
    type MRT_ColumnDef,
    type MRT_PaginationState,
    type MRT_SortingState,
} from 'material-react-table';
import axios from 'axios';
import { toast } from 'react-hot-toast';
import { Combobox } from '@headlessui/react';
import { FontAwesomeIcon } from '@fortawesome/react-fontawesome';
import { faChevronDown, faCheck } from '@fortawesome/free-solid-svg-icons';

// --- Interfaces ---
interface DropdownOption {
    id: number;
    name: string;
}

interface StockEntry {
    id: number;
    physical_item_id: number | null;
    supplier_id: number | null;
    count: number;
    price: number | null;
    bought: string | null;
    description: string | null;
    note: string | null;
    stock_position_id: number | null;
    country_of_origin_id: number | null;
    on_the_way: boolean;
    stock_batch_id: number | null;
    created_by?: number;
    updated_by?: number;
    physical_item?: DropdownOption;
    supplier?: DropdownOption;
    stock_position?: { id: number; line: string; rack: string; shelf: string; position: string };
}

interface StockEntryFormData {
    physical_item_id: number | null;
    supplier_id: number | null;
    count: number;
    price: number | null;
    bought: string | null;
    description: string | null;
    note: string | null;
    stock_position_id: number | null;
    country_of_origin_id: number | null;
    on_the_way: boolean;
    stock_batch_id: number | null;
}

const defaultForm = {
    physical_item_id: null,
    supplier_id: null,
    count: 0,
    price: null,
    bought: null,
    description: null,
    note: null,
    stock_position_id: null,
    country_of_origin_id: null,
    on_the_way: false,
    stock_batch_id: null,
};

export default function StockEntries() {
    // Table state
    const [data, setData] = useState<StockEntry[]>([]);
    const [isError, setIsError] = useState(false);
    const [isLoading, setIsLoading] = useState(false);
    const [isRefetching, setIsRefetching] = useState(false);
    const [rowCount, setRowCount] = useState(0);

    // Dropdowns
    const [stockPositions, setStockPositions] = useState<DropdownOption[]>([]);
    const [suppliers, setSuppliers] = useState<DropdownOption[]>([]);
    const [physicalItems, setPhysicalItems] = useState<DropdownOption[]>([]);
    const [originCountries, setOriginCountries] = useState<DropdownOption[]>([]);

    // Modal/form state
    const [editingEntry, setEditingEntry] = useState<StockEntry | null>(null);
    const [formData, setFormData] = useState<StockEntryFormData>(defaultForm);

    // Batch mode state
    const [isBatchMode, setIsBatchMode] = useState(false);
    const [batchSelections, setBatchSelections] = useState<number[]>([]);

    // Combobox search
    const [itemQuery, setItemQuery] = useState('');
    const filteredItems = useMemo(
        () => itemQuery === ''
            ? physicalItems
            : physicalItems.filter(item =>
                item.name.toLowerCase().includes(itemQuery.toLowerCase()),
            ),
        [itemQuery, physicalItems],
    );

    // Pagination/sorting/filtering
    const [pagination, setPagination] = useState<MRT_PaginationState>({ pageIndex: 0, pageSize: 10 });
    const [sorting, setSorting] = useState<MRT_SortingState>([{ id: 'updated_at', desc: true }]);
    const [globalFilter, setGlobalFilter] = useState('');

    // Modal ref
    const dialogRef = useRef<HTMLDialogElement>(null);
    const openModal = () => dialogRef.current?.showModal();
    const closeModal = () => dialogRef.current?.close();

    // Columns
    const columns = useMemo<MRT_ColumnDef<StockEntry>[]>(
        () => [
            { accessorKey: 'id', header: 'ID', size: 80 },
            { accessorKey: 'physical_item.name', header: 'Physical Item', size: 200 },
            { accessorKey: 'supplier.name', header: 'Supplier', size: 150 },
            { accessorKey: 'physical_item.manufacturer.name', header: 'Brand', size: 150 },
            { accessorKey: 'count', header: 'Count', size: 100 },
            { accessorKey: 'price', header: 'Price', size: 100, Cell: ({ cell }) => cell.getValue<number>()?.toFixed(2) || '-' },
            { accessorKey: 'bought', header: 'Bought Date', size: 120 },
            { accessorKey: 'on_the_way', header: 'On The Way', size: 100, Cell: ({ cell }) => cell.getValue<boolean>() ? 'Yes' : 'No' },
            { accessorKey: 'stock_position', header: 'Position', size: 150, Cell: ({ row }) => {
                    const pos = row.original.stock_position;
                    return pos ? `${pos.line}-${pos.rack}-${pos.shelf}-${pos.position}` : '-';
                }
            },
            { accessorKey: 'updated_at', header: 'Last Updated', size: 150 },
        ],
        [],
    );

    // Batch columns
    const batchColumns = useMemo<MRT_ColumnDef<StockEntry>[]>(
        () => [
            {
                accessorKey: 'select',
                header: 'Select',
                Cell: ({ row }) => {
                    const id = row.original.id;
                    return (
                        <input
                            type="checkbox"
                            checked={batchSelections.includes(id)}
                            onChange={() => setBatchSelections(prev =>
                                prev.includes(id) ? prev.filter(x => x !== id) : [...prev, id]
                            )}
                        />
                    );
                },
            },
            { accessorKey: 'id', header: 'ID' },
            { accessorKey: 'physical_item.name', header: 'Item' },
            { accessorKey: 'supplier.name', header: 'Supplier' },
        ],
        [batchSelections],
    );

    // Fetch options & data
    useEffect(() => { fetchData(); }, [pagination.pageIndex, pagination.pageSize, sorting, globalFilter]);
    useEffect(() => { fetchOptions(); }, []);

    async function fetchOptions() {
        try {
            const { data } = await axios.get('/api/stockData/options');
            setStockPositions(data.stockPositions);
            setSuppliers(data.suppliers);
            setOriginCountries(data.countriesOrigin);
        } catch {
            toast.error('Failed to load form options');
        }
    }

    async function fetchData() {
        setIsLoading(!data.length);
        setIsRefetching(!!data.length);
        try {
            const res = await axios.get('/api/stockData');
            setData(res.data.data);
            setRowCount(res.data.meta.total);
        } catch {
            setIsError(true);
            toast.error('Failed to fetch stock entries');
        } finally {
            setIsLoading(false);
            setIsRefetching(false);
        }
    }

    async function fetchPhysicalItems(query: string) {
        try {
            const res = await axios.get('/api/stockData/options/items', { params: { item_name: query } });
            setPhysicalItems(res.data.physicalItems);
        } catch {
            toast.error('Failed to load items');
        }
    }
    useEffect(() => {
        const delay = setTimeout(() => itemQuery && fetchPhysicalItems(itemQuery), 500);
        return () => clearTimeout(delay);
    }, [itemQuery]);

    // Input change
    const handleInputChange = (e: React.ChangeEvent<HTMLInputElement | HTMLTextAreaElement | HTMLSelectElement>) => {
        const { name, value, type } = e.target;
        setFormData(prev => ({
            ...prev,
            [name]: type === 'checkbox'
                ? (e.target as HTMLInputElement).checked
                : type === 'number'
                    ? parseFloat(value) || null
                    : value || null,
        }));
    };

    // Submit
    const handleSubmit = async (e: React.FormEvent) => {
        e.preventDefault();
        try {
            let res;
            if (editingEntry) {
                res = await axios.put(`/api/stockData/${editingEntry.id}`, formData);
                toast.success('Stock entry updated');
            } else {
                res = await axios.post('/api/stockData', formData);
                toast.success('Stock entry created');
            }
            const newEntry: StockEntry = res.data;
            if (isBatchMode) {
                // Add to batch and keep modal open
                setBatchSelections(prev => [...prev, newEntry.id]);
                setFormData({ ...defaultForm, on_the_way: true });
            } else {
                closeModal();
            }
            fetchData();
        } catch {
            toast.error('Failed to save');
        }
    };

    // Batch submit
    const handleBatchSubmit = async (e: React.FormEvent) => {
        e.preventDefault();
        try {
            await axios.post('/api/stockData/batch', { ids: batchSelections });
            toast.success('Batch created');
            closeModal();
            fetchData();
        } catch {
            toast.error('Batch submit failed');
        }
    };

    const handleEdit = (entry: StockEntry) => {
        setEditingEntry(entry);
        setFormData({ ...entry });
        openModal();
    };

    const handleDelete = async (id: number) => {
        if (!confirm('Are you sure?')) return;
        try {
            await axios.delete(`/api/stockData/${id}`);
            toast.success('Deleted');
            fetchData();
        } catch {
            toast.error('Failed to delete');
        }
    };

    const handleAdd = () => {
        setIsBatchMode(false);
        setEditingEntry(null);
        setFormData(defaultForm);
        openModal();
    };

    const handleNewBatch = () => {
        setIsBatchMode(true);
        setEditingEntry(null);
        setBatchSelections([]);
        setFormData({ ...defaultForm, on_the_way: true });
        openModal();
    };

    return (
        <AppLayout title="Stock Entries" renderHeader={() => (
            <h2 className="font-semibold text-xl text-gray-800 dark:text-gray-200 leading-tight">
                Stock Entries
            </h2>
        )}>
            <Head title="Stock Entries" />
            <div className="py-12">
                <div className="max-w-7xl mx-auto sm:px-6 lg:px-8">
                    <div className="bg-white dark:bg-gray-800 overflow-hidden shadow-xl sm:rounded-lg p-6">
                        <div className="mb-4 flex justify-between items-center">
                            <h1 className="text-2xl font-bold">Stock Entries</h1>
                            <div>
                                <button className="btn mr-2" onClick={handleNewBatch}>New batch</button>
                                <button className="btn" onClick={handleAdd}>Add New Entry</button>
                            </div>
                        </div>
                        <MaterialReactTable
                            columns={columns}
                            data={data}
                            enableTopToolbar
                            manualPagination
                            manualSorting
                            manualFiltering
                            onPaginationChange={setPagination}
                            onSortingChange={setSorting}
                            onGlobalFilterChange={setGlobalFilter}
                            rowCount={rowCount}
                            state={{ isLoading, pagination, showProgressBars: isRefetching, sorting, globalFilter }}
                            enableRowActions
                            renderRowActionMenuItems={({ row }) => [
                                <button key="edit" onClick={() => handleEdit(row.original)} className="menu-item">Edit</button>,
                                <button key="delete" onClick={() => handleDelete(row.original.id)} className="menu-item text-red-600">Delete</button>,
                            ]}
                        />
                    </div>
                </div>
            </div>

            {/* Modal (Add/Edit & Batch) */}
            <dialog ref={dialogRef} className="modal">
                <form onSubmit={handleSubmit} className={`modal-box flex space-x-4 p-6 ${isBatchMode ? 'max-w-full' : ''}`}>
                    <button type="button" onClick={closeModal} className="btn btn-sm btn-circle btn-ghost absolute right-2 top-2">✕</button>
                    {isBatchMode && (
                        <div className="w-2/3">
                            <h3 className="font-bold text-lg mb-2">Select Incoming Items</h3>
                            <MaterialReactTable
                                columns={batchColumns}
                                data={data.filter(e => e.on_the_way)}
                                enablePagination={false}
                                enableSorting={false}
                                enableGlobalFilter={false}
                                getRowId={row => row.id.toString()}
                            />
                        </div>
                    )}
                    <div className={isBatchMode ? 'w-1/3' : 'w-full'}>
                        <h3 className="font-bold text-lg mb-4">{isBatchMode ? 'New Batch Entry' : (editingEntry ? 'Edit Stock Entry' : 'New Stock Entry')}</h3>
                        {/* Physical Item */}
                        <div className="form-control">
                            <Combobox value={formData.physical_item_id} onChange={val => setFormData(prev => ({ ...prev, physical_item_id: val }))}>
                                <Combobox.Input
                                    onChange={e => setItemQuery(e.target.value)}
                                    displayValue={id => physicalItems.find(i => i.id === id)?.name || ''}
                                    placeholder="Select item..."
                                    className="input"
                                />
                                <Combobox.Options className="dropdown-content menu p-2 shadow bg-base-100 rounded-box max-h-60 overflow-auto">
                                    {filteredItems.map(item => (
                                        <Combobox.Option key={item.id} value={item.id} className="cursor-pointer p-2 hover:bg-gray-200">
                                            <div className="flex justify-between items-center">
                                                <span>{item.name}</span>
                                                {formData.physical_item_id === item.id && <FontAwesomeIcon icon={faCheck} />}
                                            </div>
                                        </Combobox.Option>
                                    ))}
                                </Combobox.Options>
                            </Combobox>
                        </div>

                        {/* Supplier */}
                        <div className="form-control">
                            <label className="label" htmlFor="supplier_id">
                                <span className="label-text">Supplier</span>
                            </label>
                            <select id="supplier_id" name="supplier_id" value={formData.supplier_id || ''} onChange={handleInputChange} className="select">
                                <option value="">Select supplier...</option>
                                {suppliers.map(s => <option key={s.id} value={s.id}>{s.name}</option>)}
                            </select>
                        </div>

                        {/* Count, Price, Bought Date */}
                        <div className="grid grid-cols-3 gap-4">
                            <div className="form-control">
                                <label className="label" htmlFor="count"><span className="label-text">Count</span></label>
                                <input id="count" name="count" type="number" value={formData.count} onChange={handleInputChange} className="input" />
                            </div>
                            <div className="form-control">
                                <label className="label" htmlFor="price"><span className="label-text">Price</span></label>
                                <input id="price" name="price" type="number" step="0.01" value={formData.price || ''} onChange={handleInputChange} className="input" />
                            </div>
                            <div className="form-control">
                                <label className="label" htmlFor="bought"><span className="label-text">Bought Date</span></label>
                                <input id="bought" name="bought" type="date" value={formData.bought || ''} onChange={handleInputChange} className="input" />
                            </div>
                        </div>

                        {/* Description & Note */}
                        <div className="form-control">
                            <label className="label" htmlFor="description"><span className="label-text">Description</span></label>
                            <textarea id="description" name="description" value={formData.description || ''} onChange={handleInputChange} className="textarea" />
                        </div>
                        <div className="form-control">
                            <label className="label" htmlFor="note"><span className="label-text">Note</span></label>
                            <textarea id="note" name="note" value={formData.note || ''} onChange={handleInputChange} className="textarea" />
                        </div>

                        {/* Stock Position & Country & On The Way */}
                        <div className="grid grid-cols-3 gap-4 items-end">
                            <div className="form-control">
                                <label className="label" htmlFor="stock_position_id"><span className="label-text">Position</span></label>
                                <select id="stock_position_id" name="stock_position_id" value={formData.stock_position_id || ''} onChange={handleInputChange} className="select">
                                    <option value="">Select...</option>
                                    {stockPositions.map(pos => <option key={pos.id} value={pos.id}>{pos.name}</option>)}
                                </select>
                            </div>
                            <div className="form-control">
                                <label className="label" htmlFor="supplier_id">
                                    <span className="label-text">Country</span>
                                </label>
                                <select id="country_of_origin_id" name="country_of_origin_id" value={formData.country_of_origin_id || ''} onChange={handleInputChange} className="select">
                                    <option value="">Select country...</option>
                                    {originCountries.map(s => <option key={s.id} value={s.id}>{s.name}</option>)}
                                </select>
                            </div>
                            <div className="form-control flex items-center">
                                <label className="label cursor-pointer">
                                    <input type="checkbox" name="on_the_way" checked={formData.on_the_way} onChange={handleInputChange} className="checkbox mr-2" />
                                    <span className="label-text">On The Way</span>
                                </label>
                            </div>
                        </div>

                        {/* Submit */}
                        <div className="modal-action flex justify-between">
                            {isBatchMode && (
                                <button
                                    type="button"
                                    className="btn btn-primary"
                                    disabled={batchSelections.length === 0}
                                    onClick={handleBatchSubmit}
                                >
                                    Create Batch
                                </button>
                            )}

                            <button type="submit" className="btn btn-primary">
                                {isBatchMode ? 'Create Entry' : (editingEntry ? 'Update Entry' : 'Create Entry')}
                            </button>
                        </div>
                    </div>
                </form>
            </dialog>
        </AppLayout>
    );
}