import { UserError } from 'n8n-workflow';
import type { IExecuteFunctions, ILoadOptionsFunctions } from 'n8n-workflow';

import type { DatabricksCredentials, OpenAPISchema } from './interfaces';

export function getActiveCredentialType(
	context: IExecuteFunctions | ILoadOptionsFunctions,
	itemIndex = 0,
): 'databricksApi' | 'databricksOAuth2Api' {
	const authentication = context.getNodeParameter(
		'authentication',
		itemIndex,
		'accessToken',
	) as string;
	return authentication === 'oAuth2' ? 'databricksOAuth2Api' : 'databricksApi';
}

export async function getHost(
	context: IExecuteFunctions | ILoadOptionsFunctions,
	credentialType: 'databricksApi' | 'databricksOAuth2Api',
): Promise<string> {
	const credentials = await context.getCredentials<DatabricksCredentials>(credentialType);
	return credentials.host.replace(/\/$/, '');
}

export function extractResourceLocatorValue(param: unknown): string {
	if (typeof param === 'object' && param !== null) {
		return (param as { value?: string }).value || '';
	}
	return (param as string) || '';
}

type DetectFormatResult = {
	format: string;
	schema: unknown;
	requiredFields: string[];
	invocationUrl: string;
};

function detectFormatFromProperties(
	properties: Record<string, unknown>,
	invocationUrl: string,
	isOneOf = false,
): DetectFormatResult | null {
	if (properties.messages)
		return {
			format: 'chat',
			schema: properties.messages,
			requiredFields: ['messages'],
			invocationUrl,
		};
	if (properties.prompt)
		return {
			format: 'completions',
			schema: properties.prompt,
			requiredFields: ['prompt'],
			invocationUrl,
		};
	if (
		properties.input &&
		(!isOneOf || (!properties.dataframe_records && !properties.dataframe_split))
	)
		return {
			format: 'embeddings',
			schema: properties.input,
			requiredFields: ['input'],
			invocationUrl,
		};
	if (properties.dataframe_split)
		return {
			format: 'dataframe_split',
			schema: properties.dataframe_split,
			requiredFields: ['dataframe_split'],
			invocationUrl,
		};
	if (properties.dataframe_records)
		return {
			format: 'dataframe_records',
			schema: properties.dataframe_records,
			requiredFields: ['dataframe_records'],
			invocationUrl,
		};
	if (properties.inputs)
		return {
			format: 'inputs',
			schema: properties.inputs,
			requiredFields: ['inputs'],
			invocationUrl,
		};
	if (properties.instances)
		return {
			format: 'instances',
			schema: properties.instances,
			requiredFields: ['instances'],
			invocationUrl,
		};
	return null;
}

export function detectInputFormat(openApiSchema: OpenAPISchema): DetectFormatResult {
	const invocationUrl = openApiSchema.servers?.[0]?.url;
	if (!invocationUrl) {
		throw new UserError('No server URL found in OpenAPI schema');
	}

	const pathKeys = Object.keys(openApiSchema.paths);
	if (!pathKeys.length) {
		throw new UserError('No paths found in OpenAPI schema');
	}

	const invocationPath = pathKeys[0];
	const postOperation = openApiSchema.paths[invocationPath]?.post;

	if (!postOperation?.requestBody?.content?.['application/json']?.schema) {
		throw new UserError('No request schema found');
	}

	const schema = postOperation.requestBody.content['application/json'].schema;

	if (schema.oneOf && schema.oneOf.length > 0) {
		for (const option of schema.oneOf) {
			const properties = (option.properties || {}) as Record<string, unknown>;
			const result = detectFormatFromProperties(properties, invocationUrl, true);
			if (result) return result;
		}
	}

	const properties = (schema.properties || {}) as Record<string, unknown>;
	const result = detectFormatFromProperties(properties, invocationUrl);
	if (result) return result;

	return { format: 'generic', schema, requiredFields: [], invocationUrl };
}

export function generateExampleFromSchema(schema: unknown, format: string): string {
	const schemaObj = schema as {
		properties?: Record<string, { type?: string; oneOf?: unknown[] }>;
	} | null;
	if (schemaObj?.properties) {
		try {
			const exampleObj: Record<string, unknown> = {};

			for (const [key, propValue] of Object.entries(schemaObj.properties)) {
				const propType = propValue.type;

				if (key === 'messages' && propType === 'array') {
					exampleObj.messages = [{ role: 'user', content: 'Hello! How can you help me today?' }];
				} else if (key === 'prompt' && propType === 'string') {
					exampleObj.prompt = 'What is Databricks?';
				} else if (key === 'input' && propType === 'array') {
					exampleObj.input = ['Text to embed'];
				} else if (key === 'max_tokens' && propType === 'integer') {
					exampleObj.max_tokens = 256;
				} else if (key === 'temperature' && propType === 'number') {
					exampleObj.temperature = 0.7;
				} else if (key === 'top_p' && propType === 'number') {
					exampleObj.top_p = 0.9;
				} else if (key === 'top_k' && propType === 'integer') {
					exampleObj.top_k = 40;
				} else if (key === 'stream' && propType === 'boolean') {
					exampleObj.stream = false;
				} else if (key === 'n' && propType === 'integer') {
					exampleObj.n = 1;
				} else if (key === 'stop' && propValue.oneOf) {
					exampleObj.stop = ['\\n'];
				}
			}

			if (Object.keys(exampleObj).length > 0) {
				return JSON.stringify(exampleObj, null, 2);
			}
		} catch (e) {
			// Fall through to default examples
		}
	}

	const examples: Record<string, string> = {
		chat: `{
  "messages": [
    {
      "role": "user",
      "content": "Hello! How are you?"
    }
  ],
  "max_tokens": 256,
  "temperature": 0.7
}`,
		completions: `{
  "prompt": "What is machine learning?",
  "max_tokens": 256,
  "temperature": 0.7,
  "top_p": 0.9
}`,
		embeddings: `{
  "input": [
    "Example text to embed"
  ]
}`,
		dataframe_split: `{
  "dataframe_split": {
    "columns": ["feature1", "feature2"],
    "data": [[1.0, 2.0], [3.0, 4.0]]
  }
}`,
		dataframe_records: `{
  "dataframe_records": [
    {"feature1": 1.0, "feature2": 2.0}
  ]
}`,
		inputs: `{
  "inputs": {
    "tensor1": [1, 2, 3]
  }
}`,
		instances: `{
  "instances": [
    {"tensor1": 1}
  ]
}`,
	};

	return examples[format] || '{}';
}

export function validateRequestBody(
	requestBody: Record<string, unknown>,
	detectedFormat: string,
): void {
	switch (detectedFormat) {
		case 'chat':
			if (!requestBody.messages || !Array.isArray(requestBody.messages)) {
				throw new UserError('Invalid chat format: "messages" array is required');
			}
			break;
		case 'completions':
			if (!requestBody.prompt) {
				throw new UserError('Invalid completions format: "prompt" is required');
			}
			break;
		case 'embeddings':
			if (!requestBody.input) {
				throw new UserError('Invalid embeddings format: "input" is required');
			}
			break;
		case 'dataframe_split':
			if (!(requestBody.dataframe_split as Record<string, unknown>)?.data) {
				throw new UserError('Invalid dataframe_split format: "dataframe_split.data" is required');
			}
			break;
		case 'dataframe_records':
			if (!requestBody.dataframe_records || !Array.isArray(requestBody.dataframe_records)) {
				throw new UserError(
					'Invalid dataframe_records format: "dataframe_records" array is required',
				);
			}
			break;
		case 'inputs':
			if (!requestBody.inputs) {
				throw new UserError('Invalid inputs format: "inputs" is required');
			}
			break;
		case 'instances':
			if (!requestBody.instances || !Array.isArray(requestBody.instances)) {
				throw new UserError('Invalid instances format: "instances" array is required');
			}
			break;
	}
}