interface MockResponseSpec {
	type: 'json' | 'binary' | 'error';
	body?: unknown;
	statusCode?: number;
	contentType?: string;
	filename?: string;
	sizeHint?: 'small' | 'medium' | 'large';
}

const submitQueue: MockResponseSpec[] = [];
const generateOverride: { fn?: () => Promise<unknown> } = {};
const submitCapture: { handler?: (input: MockResponseSpec) => Promise<unknown> } = {};
const quirksCapture: { handler?: () => Promise<string> } = {};

const mockGenerate = jest.fn(async (_prompt: string) => {
	if (generateOverride.fn) return await generateOverride.fn();
	const next = submitQueue.shift();
	if (next && submitCapture.handler) {
		await submitCapture.handler(next);
	}
	return { messages: [], finishReason: 'tool-calls' };
});

interface MockAgent {
	tool: jest.Mock;
	generate: jest.Mock;
}

const mockAgent: MockAgent = {
	tool: jest.fn(function (this: MockAgent, builtTool: { _name?: string; _handler?: unknown }) {
		if (builtTool._name === 'submit_response') {
			submitCapture.handler = builtTool._handler as (input: MockResponseSpec) => Promise<unknown>;
		} else if (builtTool._name === 'get_endpoint_quirks') {
			quirksCapture.handler = builtTool._handler as () => Promise<string>;
		}
		return this;
	}),
	generate: mockGenerate,
};
const mockExtractText = jest.fn((result: { _text?: string }) => result._text ?? '');

jest.mock('@n8n/instance-ai', () => ({
	createEvalAgent: jest.fn(() => mockAgent),
	extractText: mockExtractText,
	Tool: jest.fn().mockImplementation((name: string) => {
		const built: { _name: string; _handler?: unknown } = { _name: name };
		const builder = {
			description: jest.fn().mockReturnThis(),
			input: jest.fn().mockReturnThis(),
			handler: jest.fn(function (this: unknown, h: unknown) {
				built._handler = h;
				return this;
			}),
			build: jest.fn(() => built),
		};
		return builder;
	}),
}));

jest.mock('../api-docs', () => ({ fetchApiDocs: jest.fn().mockResolvedValue('') }));

jest.mock('../node-config', () => ({
	extractNodeConfig: jest.fn().mockReturnValue('{}'),
}));

jest.mock('@n8n/di', () => ({
	Container: {
		get: jest.fn().mockReturnValue({
			info: jest.fn(),
			warn: jest.fn(),
			error: jest.fn(),
			debug: jest.fn(),
		}),
	},
	// No-op decorator factory so n8n-core's @Service-decorated classes load
	// without registering against a real DI container.
	Service: () => (target: unknown) => target,
}));

import { Container } from '@n8n/di';
import { createEvalAgent, Tool } from '@n8n/instance-ai';
import FileType from 'file-type';
import FormData from 'form-data';
import type { IHttpRequestOptions, INode } from 'n8n-workflow';

import { fetchApiDocs } from '../api-docs';
import { buildDateAnchors, createLlmMockHandler } from '../mock-handler';
import { extractNodeConfig } from '../node-config';

// `restoreMocks: true` in the root jest.config wipes `.mockImplementation` set
// inside jest.mock factories before every test, so re-apply the mocks that
// matter for tests to pass. Keep in sync with the factory bodies above.
function reapplyMockImplementations() {
	jest.mocked(Container.get).mockReturnValue({
		info: jest.fn(),
		warn: jest.fn(),
		error: jest.fn(),
		debug: jest.fn(),
	});
	jest.mocked(fetchApiDocs).mockResolvedValue('');
	jest.mocked(extractNodeConfig).mockReturnValue('{}');
	jest.mocked(createEvalAgent).mockReturnValue(mockAgent as never);
	jest.mocked(Tool).mockImplementation(((name: string) => {
		const built: { _name: string; _handler?: unknown } = { _name: name };
		const builder = {
			description: jest.fn().mockReturnThis(),
			input: jest.fn().mockReturnThis(),
			handler: jest.fn(function (this: unknown, h: unknown) {
				built._handler = h;
				return this;
			}),
			build: jest.fn(() => built),
		};
		return builder;
	}) as never);
	mockAgent.tool.mockImplementation(function (
		this: MockAgent,
		builtTool: { _name?: string; _handler?: unknown },
	) {
		if (builtTool._name === 'submit_response') {
			submitCapture.handler = builtTool._handler as (input: MockResponseSpec) => Promise<unknown>;
		} else if (builtTool._name === 'get_endpoint_quirks') {
			quirksCapture.handler = builtTool._handler as () => Promise<string>;
		}
		return this;
	});
	mockGenerate.mockImplementation(async (_prompt: string) => {
		if (generateOverride.fn) return await generateOverride.fn();
		const next = submitQueue.shift();
		if (next && submitCapture.handler) {
			await submitCapture.handler(next);
		}
		return { messages: [], finishReason: 'tool-calls' };
	});
	mockExtractText.mockImplementation((result: { _text?: string }) => result._text ?? '');
}

// ---------------------------------------------------------------------------
// Helpers
// ---------------------------------------------------------------------------

function llmSubmits(spec: MockResponseSpec) {
	submitQueue.push(spec);
}

function llmDoesNotSubmit(text = '') {
	generateOverride.fn = async () => ({ messages: [], finishReason: 'stop', _text: text });
}

function llmRejects(error: Error) {
	generateOverride.fn = async () => {
		throw error;
	};
}

const baseRequest = {
	url: 'https://api.slack.com/chat.postMessage',
	method: 'POST',
} as IHttpRequestOptions;
const baseNode = { name: 'Slack', type: 'n8n-nodes-base.slack' } as INode;

async function callHandler(
	handler: ReturnType<typeof createLlmMockHandler>,
	request = baseRequest,
	node = baseNode,
) {
	const result = await handler(request, node);
	if (!result) throw new Error('Expected mock handler to return a response');
	return result;
}

beforeEach(() => {
	jest.clearAllMocks();
	reapplyMockImplementations();
	submitQueue.length = 0;
	generateOverride.fn = undefined;
	submitCapture.handler = undefined;
	quirksCapture.handler = undefined;
});

// ---------------------------------------------------------------------------
// createLlmMockHandler — response materialization via submit_response tool
// ---------------------------------------------------------------------------

describe('createLlmMockHandler', () => {
	it('should return a function', () => {
		const handler = createLlmMockHandler();
		expect(typeof handler).toBe('function');
	});

	it('should materialize JSON spec submitted via submit_response', async () => {
		llmSubmits({ type: 'json', body: { id: 1, ok: true } });
		const handler = createLlmMockHandler();
		const result = await callHandler(handler);

		expect(result).toEqual({
			body: { id: 1, ok: true },
			headers: { 'content-type': 'application/json' },
			statusCode: 200,
		});
	});

	it('should default json body to { ok: true } when body is omitted', async () => {
		llmSubmits({ type: 'json' });
		const handler = createLlmMockHandler();
		const result = await callHandler(handler);

		expect(result).toEqual({
			body: { ok: true },
			headers: { 'content-type': 'application/json' },
			statusCode: 200,
		});
	});

	it('should preserve an explicit null body (204/202-style empty payload)', async () => {
		llmSubmits({ type: 'json', body: null });
		const handler = createLlmMockHandler();
		const result = await callHandler(handler);

		expect(result).toEqual({
			body: null,
			headers: { 'content-type': 'application/json' },
			statusCode: 200,
		});
	});

	it('should materialize binary spec with a valid PDF fixture when contentType=application/pdf', async () => {
		llmSubmits({ type: 'binary', contentType: 'application/pdf', filename: 'doc.pdf' });
		const handler = createLlmMockHandler();
		const result = await callHandler(handler);

		expect(result.statusCode).toBe(200);
		expect(result.headers['content-type']).toBe('application/pdf');
		expect(Buffer.isBuffer(result.body)).toBe(true);
		const sniffed = await FileType.fromBuffer(result.body as Buffer);
		expect(sniffed?.mime).toBe('application/pdf');
		expect(sniffed?.ext).toBe('pdf');
	});

	it('should populate content-disposition and content-length headers for binary responses', async () => {
		llmSubmits({ type: 'binary', contentType: 'image/png', filename: 'logo.png' });
		const handler = createLlmMockHandler();
		const result = await callHandler(handler);

		expect(result.headers['content-disposition']).toBe('attachment; filename="logo.png"');
		expect(result.headers['content-length']).toBe(String((result.body as Buffer).length));
	});

	it('should respect sizeHint=medium for binary responses', async () => {
		llmSubmits({
			type: 'binary',
			contentType: 'application/pdf',
			filename: 'big.pdf',
			sizeHint: 'medium',
		});
		const handler = createLlmMockHandler();
		const result = await callHandler(handler);

		expect((result.body as Buffer).length).toBeGreaterThanOrEqual(64 * 1024);
	});

	it('should use default filename and content-type for binary when omitted', async () => {
		llmSubmits({ type: 'binary' });
		const handler = createLlmMockHandler();
		const result = await callHandler(handler);

		expect(result.statusCode).toBe(200);
		expect(result.headers['content-type']).toBe('application/octet-stream');
		expect(result.headers['content-disposition']).toBe('attachment; filename="mock-file.dat"');
		expect(Buffer.isBuffer(result.body)).toBe(true);
		expect((result.body as Buffer).length).toBeGreaterThan(0);
	});

	it('should materialize error spec with correct status code', async () => {
		llmSubmits({ type: 'error', statusCode: 404, body: { error: 'not found' } });
		const handler = createLlmMockHandler();
		const result = await callHandler(handler);

		expect(result).toEqual({
			body: { error: 'not found' },
			headers: { 'content-type': 'application/json' },
			statusCode: 404,
		});
	});

	it('should default error status code to 500 when omitted', async () => {
		llmSubmits({ type: 'error' });
		const handler = createLlmMockHandler();
		const result = await callHandler(handler);

		expect(result).toEqual({
			body: { error: 'Mock error' },
			headers: { 'content-type': 'application/json' },
			statusCode: 500,
		});
	});

	it('should return _evalMockError when agent does not call submit_response', async () => {
		llmDoesNotSubmit('I cannot generate this response');
		const handler = createLlmMockHandler();
		const result = await callHandler(handler);

		expect(result).toEqual({
			body: expect.objectContaining({ _evalMockError: true }),
			headers: { 'content-type': 'application/json' },
			statusCode: 200,
		});
	});

	it('should return _evalMockError when agent.generate rejects', async () => {
		llmRejects(new Error('LLM timeout'));
		const handler = createLlmMockHandler();
		const result = await callHandler(handler);

		expect(result).toEqual({
			body: expect.objectContaining({
				_evalMockError: true,
				message: expect.stringContaining('LLM timeout'),
			}),
			headers: { 'content-type': 'application/json' },
			statusCode: 200,
		});
	});

	it('should cache node config across calls for the same node name', async () => {
		const { extractNodeConfig } = require('../node-config') as {
			extractNodeConfig: jest.Mock;
		};
		extractNodeConfig.mockReturnValue('{"resource":"message"}');

		llmSubmits({ type: 'json', body: { ok: true } });
		llmSubmits({ type: 'json', body: { ok: true } });
		const handler = createLlmMockHandler();

		await handler(baseRequest, baseNode);
		await handler(baseRequest, baseNode);

		expect(extractNodeConfig).toHaveBeenCalledTimes(1);
	});

	it('should extract config separately for different node names', async () => {
		const { extractNodeConfig } = require('../node-config') as {
			extractNodeConfig: jest.Mock;
		};
		extractNodeConfig.mockReturnValue('{}');

		llmSubmits({ type: 'json', body: {} });
		llmSubmits({ type: 'json', body: {} });
		const handler = createLlmMockHandler();

		await handler(baseRequest, { name: 'Slack', type: 'n8n-nodes-base.slack' } as INode);
		await handler(baseRequest, { name: 'Gmail', type: 'n8n-nodes-base.gmail' } as INode);

		expect(extractNodeConfig).toHaveBeenCalledTimes(2);
	});
});

// ---------------------------------------------------------------------------
// Prompt construction — verify request details reach the agent
// ---------------------------------------------------------------------------

describe('prompt construction', () => {
	it('should include request body in prompt', async () => {
		llmSubmits({ type: 'json', body: {} });
		const handler = createLlmMockHandler();

		await handler(
			{ url: 'https://api.slack.com/chat.postMessage', method: 'POST', body: { text: 'hi' } },
			baseNode,
		);

		const prompt = mockGenerate.mock.calls[0][0];
		expect(prompt).toContain('"text":"hi"');
	});

	it('should include query string in prompt', async () => {
		llmSubmits({ type: 'json', body: {} });
		const handler = createLlmMockHandler();

		await handler(
			{ url: 'https://api.slack.com/channels', method: 'GET', qs: { limit: 10 } },
			baseNode,
		);

		const prompt = mockGenerate.mock.calls[0][0];
		expect(prompt).toContain('"limit":10');
	});

	it('should include scenario hints when provided', async () => {
		llmSubmits({ type: 'json', body: {} });
		const handler = createLlmMockHandler({ scenarioHints: 'return rate-limited error' });

		await handler(baseRequest, baseNode);

		const prompt = mockGenerate.mock.calls[0][0];
		expect(prompt).toContain('return rate-limited error');
	});

	it('should include global context and node hints when provided', async () => {
		llmSubmits({ type: 'json', body: {} });
		const handler = createLlmMockHandler({
			globalContext: 'project-id=abc123',
			nodeHints: { Slack: 'channel=#general' },
		});

		await handler(baseRequest, baseNode);

		const prompt = mockGenerate.mock.calls[0][0];
		expect(prompt).toContain('project-id=abc123');
		expect(prompt).toContain('channel=#general');
	});

	it('should include date anchors as the last section so they sit below API docs', async () => {
		llmSubmits({ type: 'json', body: {} });
		const handler = createLlmMockHandler();

		await handler(baseRequest, baseNode);

		const prompt = mockGenerate.mock.calls[0][0];
		expect(prompt).toContain('## Date anchors');
		expect(prompt).toMatch(/- today: \d{4}-\d{2}-\d{2}/);
		expect(prompt).toMatch(/- yesterday: \d{4}-\d{2}-\d{2}/);
		expect(prompt).toMatch(/- 14 days ago: \d{4}-\d{2}-\d{2}/);
		expect(prompt.lastIndexOf('## Date anchors')).toBeGreaterThan(
			prompt.lastIndexOf('## API documentation'),
		);
	});

	it('should add GraphQL format guidance for /graphql endpoints', async () => {
		llmSubmits({ type: 'json', body: { data: { viewer: { id: '1' } } } });
		const handler = createLlmMockHandler();

		await handler(
			{
				url: 'https://api.github.com/graphql',
				method: 'POST',
				body: { query: '{ viewer { id } }' },
			} as IHttpRequestOptions,
			{ name: 'GitHub', type: 'n8n-nodes-base.github' } as INode,
		);

		const prompt = mockGenerate.mock.calls[0][0];
		expect(prompt).toContain('GraphQL');
	});

	it('should add GraphQL format guidance when body contains query field', async () => {
		llmSubmits({ type: 'json', body: { data: {} } });
		const handler = createLlmMockHandler();

		await handler(
			{
				url: 'https://api.linear.app/v1',
				method: 'POST',
				body: { query: '{ issues { nodes { id } } }' },
			} as IHttpRequestOptions,
			{ name: 'Linear', type: 'n8n-nodes-base.httpRequest' } as INode,
		);

		const prompt = mockGenerate.mock.calls[0][0];
		expect(prompt).toContain('GraphQL');
	});

	it('should redact raw Buffer request bodies to size metadata', async () => {
		llmSubmits({ type: 'json', body: {} });
		const handler = createLlmMockHandler();

		await handler(
			{
				url: 'https://api.example.com/upload',
				method: 'POST',
				body: Buffer.from('PNG-bytes-would-go-here'),
				headers: { 'content-type': 'image/png' },
			} as unknown as IHttpRequestOptions,
			baseNode,
		);

		const prompt = mockGenerate.mock.calls[0][0];
		expect(prompt).toContain('"__redacted":"buffer"');
		expect(prompt).toContain('"contentType":"image/png"');
		expect(prompt).not.toContain('PNG-bytes-would-go-here');
	});

	it('should redact form-data multipart request bodies to part metadata', async () => {
		const fd = new FormData();
		fd.append('caption', 'hello');
		fd.append('file', Buffer.from('binary-data-here'), {
			filename: 'voice.ogg',
			contentType: 'audio/ogg',
		});

		llmSubmits({ type: 'json', body: { ok: true, file_id: 'abc' } });
		const handler = createLlmMockHandler();

		await handler(
			{
				url: 'https://api.telegram.org/bot123/sendVoice',
				method: 'POST',
				body: fd,
			} as unknown as IHttpRequestOptions,
			baseNode,
		);

		const prompt = mockGenerate.mock.calls[0][0];
		expect(prompt).toContain('"__redacted":"multipart"');
		expect(prompt).toContain('"name":"caption"');
		expect(prompt).toContain('"name":"file"');
		expect(prompt).toContain('"filename":"voice.ogg"');
		expect(prompt).toContain('"contentType":"audio/ogg"');
		expect(prompt).not.toContain('binary-data-here');
	});

	it('should default method to GET when not specified', async () => {
		llmSubmits({ type: 'json', body: {} });
		const handler = createLlmMockHandler();

		await handler({ url: 'https://api.slack.com/channels' }, baseNode);

		const prompt = mockGenerate.mock.calls[0][0];
		expect(prompt).toContain('GET');
	});
});

// ---------------------------------------------------------------------------
// extractServiceName — tested indirectly through prompt content
// ---------------------------------------------------------------------------

describe('service name extraction (via prompt)', () => {
	it('should extract "Slack" from api.slack.com', async () => {
		llmSubmits({ type: 'json', body: {} });
		const handler = createLlmMockHandler();

		await handler({ url: 'https://api.slack.com/chat.postMessage' }, baseNode);

		const prompt = mockGenerate.mock.calls[0][0];
		expect(prompt).toContain('Service: Slack');
	});

	it('should extract "Googleapis" from www.googleapis.com', async () => {
		llmSubmits({ type: 'json', body: {} });
		const handler = createLlmMockHandler();

		await handler(
			{ url: 'https://www.googleapis.com/sheets/v4/spreadsheets' } as IHttpRequestOptions,
			{ name: 'Sheets', type: 'n8n-nodes-base.googleSheets' } as INode,
		);

		const prompt = mockGenerate.mock.calls[0][0];
		expect(prompt).toContain('Service: Googleapis');
	});

	it('should return "Unknown" for invalid URLs', async () => {
		llmSubmits({ type: 'json', body: {} });
		const handler = createLlmMockHandler();

		await handler({ url: 'not-a-url' }, baseNode);

		const prompt = mockGenerate.mock.calls[0][0];
		expect(prompt).toContain('Service: Unknown');
	});
});

// ---------------------------------------------------------------------------
// extractEndpoint — tested indirectly through prompt content
// ---------------------------------------------------------------------------

describe('endpoint extraction (via prompt)', () => {
	it('should extract path and query from URL', async () => {
		llmSubmits({ type: 'json', body: {} });
		const handler = createLlmMockHandler();

		await handler(
			{ url: 'https://api.slack.com/conversations.list?limit=100&cursor=abc' },
			baseNode,
		);

		const prompt = mockGenerate.mock.calls[0][0];
		expect(prompt).toContain('/conversations.list?limit=100&cursor=abc');
	});

	it('should extract path without query when there is none', async () => {
		llmSubmits({ type: 'json', body: {} });
		const handler = createLlmMockHandler();

		await handler({ url: 'https://api.slack.com/chat.postMessage' }, baseNode);

		const prompt = mockGenerate.mock.calls[0][0];
		expect(prompt).toContain('/chat.postMessage');
		const match = prompt.match(/(?:GET|POST)\s+(\S+)/);
		expect(match?.[1]).not.toContain('?');
	});

	it('should fall back to raw url for invalid URLs', async () => {
		llmSubmits({ type: 'json', body: {} });
		const handler = createLlmMockHandler();

		await handler({ url: 'not-a-url', method: 'GET' }, baseNode);

		const prompt = mockGenerate.mock.calls[0][0];
		expect(prompt).toContain('GET not-a-url');
	});
});

// ---------------------------------------------------------------------------
// buildDateAnchors — date math used to seed the user prompt
// ---------------------------------------------------------------------------

describe('buildDateAnchors', () => {
	it('renders today plus the standard set of relative anchors', () => {
		const fixed = new Date('2026-05-12T14:30:00.000Z');
		const block = buildDateAnchors(fixed);

		expect(block).toContain('- today: 2026-05-12');
		expect(block).toContain('full timestamp 2026-05-12T14:30:00.000Z');
		expect(block).toContain('- yesterday: 2026-05-11');
		expect(block).toContain('- 7 days ago: 2026-05-05');
		expect(block).toContain('- 14 days ago: 2026-04-28');
		expect(block).toContain('- 30 days ago: 2026-04-12');
		expect(block).toContain('- 1 day from now: 2026-05-13');
		expect(block).toContain('- 7 days from now: 2026-05-19');
	});

	it('uses UTC for date math (avoids local-timezone drift around midnight)', () => {
		// 23:59 UTC on the 12th — local time in many zones would tip to the 13th.
		const fixed = new Date('2026-05-12T23:59:00.000Z');
		const block = buildDateAnchors(fixed);
		expect(block).toContain('- today: 2026-05-12');
		expect(block).toContain('- yesterday: 2026-05-11');
	});
});

// ---------------------------------------------------------------------------
// get_endpoint_quirks tool — registered alongside submit_response and bound
// to the live request context
// ---------------------------------------------------------------------------

describe('get_endpoint_quirks tool', () => {
	it('is registered on every handler invocation', async () => {
		llmSubmits({ type: 'json', body: {} });
		const handler = createLlmMockHandler();

		await callHandler(handler);

		expect(quirksCapture.handler).toBeDefined();
	});

	it('returns guidance for a known service (Notion)', async () => {
		llmSubmits({ type: 'json', body: {} });
		const handler = createLlmMockHandler();

		await handler({ url: 'https://api.notion.com/v1/pages', method: 'POST' }, {
			name: 'Notion',
			type: 'n8n-nodes-base.notion',
		} as INode);

		expect(quirksCapture.handler).toBeDefined();
		const result = await quirksCapture.handler!();
		expect(result).toMatch(/full|FULL/);
	});

	it('returns the no-quirks message for services without registered quirks', async () => {
		llmSubmits({ type: 'json', body: {} });
		const handler = createLlmMockHandler();

		await handler({ url: 'https://api.github.com/repos/owner/name/issues', method: 'GET' }, {
			name: 'GitHub',
			type: 'n8n-nodes-base.github',
		} as INode);

		expect(quirksCapture.handler).toBeDefined();
		const result = await quirksCapture.handler!();
		expect(result).toContain('No specific quirks');
	});
});