import { CheckOutlined, EditOutlined } from '@ant-design/icons';
import { Alert, Button, Space, Splitter, Switch, message } from 'antd';
import { useCallback, useEffect, useMemo, useState } from 'react';
import { ApiError } from '../../api/client';
import { acceptChecks, confirmDocument, getStatement, patchStatement } from '../../services/api/documents';
import type { DocumentOut, FailedCheckOut, StatementOut, StatementPatch } from '../../types/api';
import { parseAmountInput } from '../../utils/money';
import { ChecksPanel, failureText } from './ChecksPanel';
import { ReviewCard, confirmButtonStyle } from './ReviewCard';
import { SourcePreview } from './SourcePreview';
import { type HeaderDraft, StatementHeaderBlock } from './StatementHeaderBlock';
import { StatementTable } from './StatementTable';
import { confirmErrorInfo } from './confirmError';
import { reviewActions } from './reviewView';
import { applyDraftInput, buildStatementGrid, draftToPatch, emptySublineKeys } from './statementGrid';

const errorText = (e: unknown, fallback: string) => (e instanceof ApiError ? e.message : fallback);

export function StatementReview({ document, onChanged }: { document: DocumentOut; onChanged: () => void }) {
	const [statement, setStatement] = useState<StatementOut | null>(null);
	const [loadError, setLoadError] = useState<string | null>(null);
	const [draft, setDraft] = useState<Record<string, string>>({});
	const [header, setHeader] = useState<HeaderDraft>({});
	const [editing, setEditing] = useState(false);
	const [saving, setSaving] = useState(false);
	const [confirmFailures, setConfirmFailures] = useState<FailedCheckOut[]>([]);
	const [confirmMessage, setConfirmMessage] = useState<string | null>(null);
	const [showEmptySublines, setShowEmptySublines] = useState(false);

	const load = useCallback(async () => {
		try {
			setStatement(await getStatement(document.id));
			setLoadError(null);
		} catch (e: unknown) {
			setLoadError(errorText(e, 'Не удалось получить форму'));
		}
	}, [document.id]);

	useEffect(() => {
		void load();
	}, [load]);

	const grid = useMemo(() => (statement ? buildStatementGrid(statement) : null), [statement]);
	// пустые строки детализации скрыты по умолчанию (только показ: PATCH и черновик работают по всем строкам формы)
	const emptySublines = useMemo(() => (grid ? emptySublineKeys(grid.rows, draft) : new Set<string>()), [grid, draft]);
	const shownRows = useMemo(() => {
		if (!grid) return [];
		return showEmptySublines ? grid.rows : grid.rows.filter((row) => !emptySublines.has(row.key));
	}, [grid, showEmptySublines, emptySublines]);
	const actions = reviewActions(statement?.document.status ?? 'ERROR', editing);
	// ячейки редактируются только в режиме правки; принять нарушения можно, пока документ не подтверждён
	const changeable = statement !== null && statement.document.status !== 'CONFIRMED' && statement.document.status !== 'ERROR';
	const dirty = Object.keys(draft).length > 0 || Object.keys(header).length > 0;

	const save = async () => {
		const values: Record<string, string | null> = {};
		for (const [key, text] of Object.entries(draft)) {
			const parsed = parseAmountInput(text);
			if (!parsed.ok) {
				message.error('Исправьте суммы с неверным форматом');
				return;
			}
			values[key] = parsed.value;
		}
		const body: StatementPatch = {};
		if (Object.keys(values).length > 0) {
			body.values = draftToPatch(values, grid?.rows ?? []);
		}
		const headerPatch: HeaderDraft = {};
		for (const field of ['inn', 'report_date', 'units'] as const) {
			const text = header[field]?.trim();
			if (text) {
				headerPatch[field] = text;
			}
		}
		if (Object.keys(headerPatch).length > 0) {
			body.header = headerPatch;
		}
		if (!body.values && !body.header) {
			cancel();
			return;
		}
		setSaving(true);
		try {
			// ответ сервера целиком заменяет состояние: он пересчитал проверки и мог сбросить акцепт
			setStatement(await patchStatement(document.id, body));
			setDraft({});
			setHeader({});
			setEditing(false);
			setConfirmFailures([]);
			setConfirmMessage(null);
			message.success('Изменения сохранены');
			onChanged();
		} catch (e: unknown) {
			message.error(errorText(e, 'Не удалось сохранить изменения'));
		} finally {
			setSaving(false);
		}
	};

	const cancel = () => {
		setDraft({});
		setHeader({});
		setEditing(false);
	};

	const accept = async (comment: string) => {
		try {
			setStatement(await acceptChecks(document.id, comment));
			onChanged();
			setConfirmFailures([]);
			setConfirmMessage(null);
		} catch (e: unknown) {
			message.error(errorText(e, 'Не удалось принять нарушения'));
			throw e;
		}
	};

	const confirm = async () => {
		try {
			await confirmDocument(document.id);
			message.success('Документ подтверждён');
			setConfirmFailures([]);
			setConfirmMessage(null);
			onChanged();
			await load();
		} catch (e: unknown) {
			const info = confirmErrorInfo(e);
			setConfirmFailures(info.failures);
			setConfirmMessage(info.code === 'PERIOD_REQUIRED' ? `${info.message}. Исправьте дату отчёта в шапке и сохраните.` : info.message);
		}
	};

	if (loadError) {
		return <Alert type='error' showIcon title={loadError} action={<Button onClick={() => void load()}>Повторить</Button>} />;
	}
	if (!statement || !grid) {
		return null;
	}

	const cardActions = editing ? (
		<Space>
			<Button
				type='primary'
				icon={<CheckOutlined />}
				style={confirmButtonStyle}
				loading={saving}
				disabled={!actions.canSave}
				onClick={save}>
				Сохранить
			</Button>
			<Button onClick={cancel}>Отменить</Button>
		</Space>
	) : (
		<Space>
			<Button icon={<EditOutlined />} disabled={!actions.canEdit} onClick={() => setEditing(true)}>
				Редактировать
			</Button>
			<Button
				type='primary'
				icon={<CheckOutlined />}
				style={actions.canConfirm ? confirmButtonStyle : undefined}
				disabled={!actions.canConfirm}
				onClick={confirm}>
				Подтвердить данные
			</Button>
		</Space>
	);

	return (
		<Splitter style={{ height: '100%' }}>
			<Splitter.Panel defaultSize='45%' min='25%'>
				<div style={{ height: '100%', paddingRight: 6 }}>
					<SourcePreview fileId={statement.document.file_id} />
				</div>
			</Splitter.Panel>
			<Splitter.Panel>
				<div style={{ height: '100%', paddingLeft: 6 }}>
					<ReviewCard title='Результат распознавания' extra={cardActions}>
						<Space orientation='vertical' size={12} style={{ width: '100%' }}>
							<StatementHeaderBlock
								header={statement.header}
								documentType={statement.document.document_type}
								editing={editing}
								draft={header}
								onDraftChange={(field, text) => setHeader((prev) => ({ ...prev, [field]: text }))}
							/>
							<ChecksPanel checks={statement.checks} editable={changeable} dirty={dirty} onAccept={accept} />
							{confirmMessage && (
								<Alert
									type='error'
									showIcon
									title={confirmMessage}
									description={
										confirmFailures.length > 0
											? confirmFailures.map((f) => <div key={`${f.column_index}-${f.relation}`}>{failureText(f)}</div>)
											: undefined
									}
								/>
							)}
							{emptySublines.size > 0 && (
								<span style={{ display: 'inline-flex', alignItems: 'center', gap: 8 }}>
									<Switch id='show-empty-sublines' size='small' checked={showEmptySublines} onChange={setShowEmptySublines} />
									<label htmlFor='show-empty-sublines' style={{ cursor: 'pointer' }}>
										Показать пустые строки детализации ({emptySublines.size})
									</label>
								</span>
							)}
							<StatementTable
								documentType={statement.document.document_type}
								columns={grid.columns}
								rows={shownRows}
								editable={editing && actions.canSave}
								draft={draft}
								onDraftChange={(key, text, original) => setDraft((prev) => applyDraftInput(prev, key, text, original, parseAmountInput))}
							/>
						</Space>
					</ReviewCard>
				</div>
			</Splitter.Panel>
		</Splitter>
	);
}