import type { WorkflowJSON } from '@n8n/workflow-sdk';

import { analyzeAgentInputColumns } from '../analyze-agent-input-columns.service';

type TestNode = Partial<WorkflowJSON['nodes'][number]>;

const wf = (nodes: TestNode[]): WorkflowJSON =>
	({
		name: 't',
		nodes,
		connections: {},
		pinData: {},
		settings: {},
	}) as unknown as WorkflowJSON;

describe('analyzeAgentInputColumns', () => {
	it('extracts $json.<field> from agent prompt parameter', () => {
		const workflow = wf([
			{
				name: 'Agent',
				type: '@n8n/n8n-nodes-langchain.agent',
				typeVersion: 1,
				parameters: { text: '={{ $json.user_query }}' },
				position: [0, 0],
				id: 'a',
			},
		]);
		const result = analyzeAgentInputColumns(workflow, 'Agent');
		expect(result).toEqual({ agentNodeName: 'Agent', inputColumns: ['user_query'] });
	});

	it('aggregates references across multiple parameters', () => {
		const workflow = wf([
			{
				name: 'Agent',
				type: '@n8n/n8n-nodes-langchain.agent',
				typeVersion: 1,
				parameters: {
					text: '={{ $json.user_query }}',
					options: { systemMessage: '={{ $json.system_prompt }}' },
				},
				position: [0, 0],
				id: 'a',
			},
		]);
		const result = analyzeAgentInputColumns(workflow, 'Agent');
		expect(result.inputColumns.sort()).toEqual(['system_prompt', 'user_query']);
	});

	it('falls back to ["input"] when no $json refs are found', () => {
		const workflow = wf([
			{
				name: 'Agent',
				type: '@n8n/n8n-nodes-langchain.agent',
				typeVersion: 1,
				parameters: { text: 'literal prompt with no expressions' },
				position: [0, 0],
				id: 'a',
			},
		]);
		const result = analyzeAgentInputColumns(workflow, 'Agent');
		expect(result.inputColumns).toEqual(['input']);
	});

	it('throws when the named agent node does not exist', () => {
		const workflow = wf([]);
		expect(() => analyzeAgentInputColumns(workflow, 'Missing')).toThrow(/not found/i);
	});

	it('matches both item.json.<field> and $json.<field>', () => {
		const workflow = wf([
			{
				name: 'Agent',
				type: '@n8n/n8n-nodes-langchain.agent',
				typeVersion: 1,
				parameters: {
					text: '={{ $json.q }}',
					options: { systemMessage: '={{ $input.item.json.context }}' },
				},
				position: [0, 0],
				id: 'a',
			},
		]);
		const result = analyzeAgentInputColumns(workflow, 'Agent');
		expect(result.inputColumns.sort()).toEqual(['context', 'q']);
	});
});