import { NodeOperationError } from 'n8n-workflow';
import type { IDataObject, IExecuteFunctions, INodeExecutionData } from 'n8n-workflow';

import { sleep } from '@n8n/utils/sleep';
import {
	databricksApiRequest,
	extractResourceLocatorValue,
	getActiveCredentialType,
	getHost,
	sanitizeApiMessage,
} from '../helpers';
import type { DatabricksStatementResponse } from '../interfaces';

export async function execute(this: IExecuteFunctions, i: number): Promise<INodeExecutionData[]> {
	const credentialType = getActiveCredentialType(this, i);
	const host = await getHost(this, credentialType);
	const warehouseId = extractResourceLocatorValue(this.getNodeParameter('warehouseId', i));
	const query = this.getNodeParameter('query', i) as string;
	const rawParams = this.getNodeParameter('queryParameters.parameters', i, []) as Array<{
		name: string;
		value: string;
		type: string;
	}>;
	const parameters = rawParams.map(({ name, value, type }) =>
		type ? { name, value, type } : { name, value },
	);

	// Step 1: Execute the query.
	// wait_timeout is set to the API maximum (50s) so that short queries return
	// results synchronously in this single request — no polling required.
	// For queries that exceed 50s, on_wait_timeout=CONTINUE puts the statement
	// in async mode and Step 2 polls until it finishes.
	// See: https://docs.databricks.com/api/workspace/statementexecution/executestatement#wait_timeout
	const executeResponse = (await databricksApiRequest(this, credentialType, {
		method: 'POST',
		url: `${host}/api/2.0/sql/statements`,
		body: {
			warehouse_id: warehouseId,
			statement: query,
			wait_timeout: '50s',
			on_wait_timeout: 'CONTINUE',
			...(parameters.length > 0 && { parameters }),
		},
		headers: { 'Content-Type': 'application/json' },
		json: true,
	})) as DatabricksStatementResponse;

	const statementId = executeResponse.statement_id;

	// Step 2: Poll for completion (if in async mode)
	let status = executeResponse.status.state;
	let queryResult = executeResponse;
	const maxRetries = 60; // Max 5 minutes (60 * 5 seconds)
	let retries = 0;

	while (
		status !== 'SUCCEEDED' &&
		status !== 'FAILED' &&
		status !== 'CANCELED' &&
		retries < maxRetries
	) {
		await sleep(5000);

		queryResult = (await databricksApiRequest(this, credentialType, {
			method: 'GET',
			url: `${host}/api/2.0/sql/statements/${statementId}`,
			headers: { Accept: 'application/json' },
			json: true,
		})) as DatabricksStatementResponse;

		status = queryResult.status.state;
		retries++;
	}

	if (status === 'FAILED' || status === 'CANCELED') {
		// Databricks reports SQL permission failures in-band on an HTTP 200: prefer
		// the legible status.error.message over the raw status blob when present
		const apiMessage = queryResult.status.error?.message;
		const reason =
			typeof apiMessage === 'string' && apiMessage
				? sanitizeApiMessage(apiMessage)
				: JSON.stringify(queryResult.status);
		throw new NodeOperationError(this.getNode(), `Query ${status.toLowerCase()}: ${reason}`, {
			itemIndex: i,
		});
	}

	if (retries >= maxRetries) {
		throw new NodeOperationError(
			this.getNode(),
			'Query execution timeout - exceeded maximum wait time',
			{ itemIndex: i },
		);
	}

	// Step 3: Collect all chunks
	const allRows: unknown[][] = [];
	let chunkIndex = 0;
	const totalChunks = queryResult.manifest?.total_chunk_count || 0;

	if (queryResult.result?.data_array) {
		for (const row of queryResult.result.data_array) {
			allRows.push(row);
		}
		chunkIndex = 1;
	}

	while (chunkIndex < totalChunks) {
		const chunkResponse = (await databricksApiRequest(this, credentialType, {
			method: 'GET',
			url: `${host}/api/2.0/sql/statements/${statementId}/result/chunks/${chunkIndex}`,
			headers: { Accept: 'application/json' },
			json: true,
		})) as { data_array?: unknown[][] };

		if (chunkResponse.data_array) {
			for (const row of chunkResponse.data_array) {
				allRows.push(row);
			}
		}

		chunkIndex++;
	}

	// Step 4: Transform rows into objects using column names
	const columns = queryResult.manifest?.schema?.columns || [];
	const returnData: INodeExecutionData[] = allRows.map((row) => {
		const obj: IDataObject = {};
		columns.forEach((col, idx) => {
			obj[col.name] = row[idx] as IDataObject;
		});
		return { json: obj, pairedItem: { item: i } };
	});

	return returnData;
}