import RefreshRoundedIcon from '@mui/icons-material/RefreshRounded';
import { Alert, Box, Button, Paper, Tab, Tabs, Typography } from '@mui/material';
import { useCallback, useEffect, useMemo, useRef, useState } from 'react';
import { useNavigate } from 'react-router-dom';
import { HeaderSwitch } from '../../components/HeaderMenu/HeaderSwitch';
import { PrimaryButton, PrimaryOutlinedButton } from '../../components/common/Buttons/Buttons';
import { SummaryTable, buildSummaryTree, countSummaryTree, filterSummaryTree } from './SummaryTable';
import { useSvod } from './SvodContext';
import { SvodFilters } from './SvodFilters';

const SHEETS = [
	{ value: 'MAIN', label: 'Общий свод' },
	{ value: 'FORM_1', label: 'Смета ССП' },
	{ value: 'FORM_2', label: 'Смета РФ' },
	{ value: 'FORM_3', label: 'Проекты РФ Развитие' },
	{ value: 'FORM_4', label: 'Проектная деятельность' },
];
const METRICS = [
	{ key: 'plan', label: 'План' },
	{ key: 'approved', label: 'Утверждено' },
	{ key: 'fact', label: 'Факт' },
	{ key: 'corrected', label: 'Скорректированный план' },
];
const FORM_3_METRIC_LABELS = {
	plan: 'Расходы, планируемые РФ',
	approved: 'Утвержденные базовые расходы',
	fact: 'Фактические расходы',
	corrected: 'Скорректированная смета расходов',
};
const DIRECTIONS = [
	{ key: 'support', label: 'Поддержка' },
	{ key: 'development', label: 'Развитие' },
];
const QUARTERS = [
	{ key: 'q1', label: 'I кв.' },
	{ key: 'q2', label: 'II кв.' },
	{ key: 'q3', label: 'III кв.' },
	{ key: 'q4', label: 'IV кв.' },
	{ key: 'year', label: 'Год' },
];
const FORM_3_QUARTERS = [
	{ key: 'q1', label: 'I квартал' },
	{ key: 'q2', label: 'II квартал' },
	{ key: 'q3', label: 'III квартал' },
	{ key: 'q4', label: 'IV квартал' },
	{ key: 'year', label: 'ИТОГО Развитие' },
];
const numberFormatter = new Intl.NumberFormat('ru-RU', { maximumFractionDigits: 2 });
const valueAt = (row, path) => path.reduce((value, key) => value?.[key], row.data);
const tableSize = (rem) => rem * 16;

const formatValue = (value) => {
	if (value === null || value === undefined || value === '') return '—';
	const numericValue = typeof value === 'number' ? value : Number(value);
	if (numericValue === 0) return '-';
	return Number.isNaN(numericValue) ? value : numberFormatter.format(numericValue);
};

const getShapeForSheet = (sheet) => {
	const directionShape = { q1: 0, q2: 0, q3: 0, q4: 0, year: 0 };
	const correctedShape = { q2: 0, q3: 0, q4: 0 };
	return {
		plan: { support: directionShape, development: directionShape, ...(['FORM_1', 'MAIN'].includes(sheet) ? { total_year: 0 } : {}) },
		approved: { support: directionShape, development: directionShape, ...(['FORM_1', 'MAIN'].includes(sheet) ? { total_year: 0 } : {}) },
		fact: { support: directionShape, development: directionShape, ...(['FORM_1', 'MAIN'].includes(sheet) ? { total_year: 0 } : {}) },
		corrected: { support: correctedShape, development: correctedShape },
	};
};

const valueColumn = (metric, direction, period) => ({
	id: `${metric.key}.${direction.key}.${period.key}`,
	header: period.label,
	accessorFn: (row) => valueAt(row, [metric.key, direction.key, period.key]),
	Cell: ({ cell }) => formatValue(cell.getValue()),
	size: tableSize(period.key === 'year' ? 8 : 6.75),
	muiTableBodyCellProps: { align: 'right' },
	muiTableHeadCellProps: { align: 'right' },
});

const createForm3MetricColumns = (metric) => ({
	id: metric.key,
	header: FORM_3_METRIC_LABELS[metric.key],
	columns: FORM_3_QUARTERS.filter(({ key }) =>
		valueAt({ data: getShapeForSheet('FORM_3') }, [metric.key, 'development', key]) !== undefined,
	).map((period) => ({
		...valueColumn(metric, { key: 'development' }, period),
		id: metric.key + '.' + period.key,
	})),
});

const createColumns = (sheet) => {
	let visibleDirections = DIRECTIONS;
	if (sheet === 'FORM_2') visibleDirections = DIRECTIONS.filter(({ key }) => key === 'support');
	if (['FORM_3', 'FORM_4'].includes(sheet)) visibleDirections = DIRECTIONS.filter(({ key }) => key === 'development');
	const shape = getShapeForSheet(sheet);
	if (sheet === 'FORM_3') {
		return [
			{ id: 'section_code', header: '№ п/п', accessorFn: (row) => row.data?.section_code, size: tableSize(5.75) },
			{
				id: 'name',
				header: 'Перечень расходов и затрат',
				accessorFn: (row) => row.data?.name,
				size: tableSize(20.625),
				Cell: ({ cell, row }) => (
					<Box sx={{ pl: row.original.depth * 1.125 + 'rem', fontWeight: row.original.depth < 2 ? 600 : 400 }}>
						{cell.getValue() || 'Без названия'}
					</Box>
				),
			},
			...METRICS.map(createForm3MetricColumns),
		];
	}
	const metricColumns = METRICS.map((metric) => ({
		id: metric.key,
		header: sheet === 'FORM_3' ? FORM_3_METRIC_LABELS[metric.key] : metric.label,
		columns: visibleDirections
			.map((direction) => ({
				id: `${metric.key}.${direction.key}`,
				header: direction.label,
				columns: QUARTERS.filter(({ key }) => valueAt({ data: shape }, [metric.key, direction.key, key]) !== undefined).map((period) =>
					valueColumn(metric, direction, period),
				),
			}))
			.concat(
				shape[metric.key].total_year === undefined
					? []
					: [
							{
								id: `${metric.key}.total`,
								header: 'Итого',
								columns: [
									{
										id: `${metric.key}.total_year`,
										header: 'Год',
										accessorFn: (row) => valueAt(row, [metric.key, 'total_year']),
										Cell: ({ cell }) => formatValue(cell.getValue()),
										size: tableSize(8.25),
										muiTableBodyCellProps: { align: 'right' },
										muiTableHeadCellProps: { align: 'right' },
									},
								],
							},
						],
			),
	}));
	return [
		{ id: 'section_code', header: 'Код', accessorFn: (row) => row.data?.section_code, size: tableSize(5.75) },
		{
			id: 'name',
			header: 'Статья расходов',
			accessorFn: (row) => row.data?.name,
			size: tableSize(20.625),
			Cell: ({ cell, row }) => (
				<Box sx={{ pl: `${row.original.depth * 1.125}rem`, fontWeight: row.original.depth < 2 ? 600 : 400 }}>
					{cell.getValue() || 'Без названия'}
				</Box>
			),
		},
		...metricColumns,
	];
};

export default function SvodPage() {
	const navigate = useNavigate();
	const { getSheetFilters, updateSheetFilters, getSummary, invalidateSummary } = useSvod();
	const [sheet, setSheet] = useState('MAIN');
	const [rows, setRows] = useState([]);
	const [loading, setLoading] = useState(true);
	const [error, setError] = useState('');
	const latestSummaryRequestRef = useRef(0);
	const { year, selectedOrganizations, search } = getSheetFilters(sheet);
	const updateCurrentSheetFilters = useCallback(
		(changes) => {
			updateSheetFilters(sheet, changes);
		},
		[sheet, updateSheetFilters],
	);

	const loadSummary = useCallback(async () => {
		const requestId = latestSummaryRequestRef.current + 1;
		latestSummaryRequestRef.current = requestId;
		setLoading(true);
		setError('');
		try {
			const response = await getSummary(
				sheet,
				year,
				selectedOrganizations.map(({ id }) => id),
			);
			if (latestSummaryRequestRef.current !== requestId) return;
			setRows([...(response.result || [])].sort((a, b) => (a.sort_order ?? 0) - (b.sort_order ?? 0)));
		} catch (loadError) {
			if (latestSummaryRequestRef.current !== requestId) return;
			setRows([]);
			setError(loadError.response?.data?.detail || 'Не удалось загрузить свод. Попробуйте ещё раз.');
		} finally {
			if (latestSummaryRequestRef.current === requestId) setLoading(false);
		}
	}, [getSummary, selectedOrganizations, sheet, year]);

	useEffect(() => {
		loadSummary();
		return () => {
			latestSummaryRequestRef.current += 1;
		};
	}, [loadSummary]);

	const refreshSummary = useCallback(() => {
		invalidateSummary(
			sheet,
			year,
			selectedOrganizations.map(({ id }) => id),
		);
		loadSummary();
	}, [invalidateSummary, loadSummary, selectedOrganizations, sheet, year]);

	const openFilteredTasks = useCallback(() => {
		const params = new URLSearchParams({ year: String(year) });
		const organizationIds = selectedOrganizations.map(({ id }) => id);
		if (organizationIds.length > 0) params.set('org_units', organizationIds.join(','));
		if (sheet !== 'MAIN') params.set('form_type', sheet);
		navigate(`/tasks?${params.toString()}`);
	}, [navigate, selectedOrganizations, sheet, year]);

	const openFilteredProjects = useCallback(() => {
		const params = new URLSearchParams();
		const organizationIds = selectedOrganizations.map(({ id }) => id);
		if (organizationIds.length > 0) params.set('branch_ids', organizationIds.join(','));
		const query = params.toString();
		navigate(query ? `/projects?${query}` : '/projects');
	}, [navigate, selectedOrganizations]);

	const tree = useMemo(() => buildSummaryTree(rows), [rows]);
	const filteredRows = useMemo(() => {
		const normalizedSearch = search.trim().toLowerCase();
		return normalizedSearch ? filterSummaryTree(tree, normalizedSearch) : tree;
	}, [tree, search]);
	const columns = useMemo(() => createColumns(sheet), [sheet]);
	const filteredRowsCount = useMemo(() => countSummaryTree(filteredRows), [filteredRows]);

	return (
		<Box
			sx={{
				px: '2rem',
				pt: '1rem',
				pb: '1.5rem',
				height: '100%',
				minHeight: 0,
				overflow: 'hidden',
				display: 'flex',
				flexDirection: 'column',
				gap: '1rem',
			}}>
			<HeaderSwitch />

			<Paper elevation={0} sx={{ border: '0.0625rem solid #e5e7eb', borderRadius: '0.75rem', overflow: 'hidden', flexShrink: 0 }}>
				<Tabs
					value={sheet}
					onChange={(_event, value) => setSheet(value)}
					variant='scrollable'
					scrollButtons='auto'
					sx={{ px: '1rem', minHeight: '3rem', borderBottom: '0.0625rem solid #edf0f2' }}>
					{SHEETS.map((item) => (
						<Tab key={item.value} value={item.value} label={item.label} sx={{ textTransform: 'none', alignItems: 'flex-start', textAlign: 'left', minHeight: '3rem' }} />
					))}
				</Tabs>
				<SvodFilters year={year} selectedOrganizations={selectedOrganizations} search={search} onChange={updateCurrentSheetFilters}>
					{!loading && filteredRowsCount !== rows.length && (
						<Typography variant='caption' color='text.secondary' sx={{ flexShrink: 0, whiteSpace: 'nowrap' }}>
							{`Найдено ${filteredRowsCount.toLocaleString('ru-RU')} из ${rows.length.toLocaleString('ru-RU')} строк`}
						</Typography>
					)}
					{sheet === 'FORM_3' ? (
						<PrimaryButton variant='contained' onClick={openFilteredProjects} sx={{ ml: 'auto', height: '2.5rem', flexShrink: 0 }}>
							Перейти к проектам
						</PrimaryButton>
					) : (
						<PrimaryButton variant='contained' onClick={openFilteredTasks} sx={{ ml: 'auto', height: '2.5rem', flexShrink: 0 }}>
							Перейти к задачам
						</PrimaryButton>
					)}
					<PrimaryOutlinedButton
						variant='outlined'
						color='default'
						startIcon={<RefreshRoundedIcon />}
						disabled={loading}
						onClick={refreshSummary}
						sx={{ height: '2.5rem', flexShrink: 0 }}>
						Обновить
					</PrimaryOutlinedButton>
				</SvodFilters>
			</Paper>
			{error ? (
				<Alert
					severity='error'
					action={
						<Button color='inherit' size='small' onClick={refreshSummary}>
							Повторить
						</Button>
					}>
					{error}
				</Alert>
			) : (
				<SummaryTable columns={columns} data={filteredRows} loading={loading} />
			)}
		</Box>
	);
}