import getPort from 'get-port';
import type { StartedNetwork, StartedTestContainer, StoppedTestContainer } from 'testcontainers';
import { Network } from 'testcontainers';

import { createElapsedLogger, pollContainerHttpEndpoint } from './helpers/utils';
import { waitForNetworkQuiet } from './network-stabilization';
import type { LoadBalancerResult } from './services/load-balancer';
import type { N8NStartupDiagnostics } from './services/n8n';
import { createN8NInstances, N8NStartupError } from './services/n8n';
import { helperFactories, services } from './services/registry';
import type {
	FileToMount,
	HelperContext,
	HelperFactories,
	Service,
	ServiceHelpers,
	ServiceName,
	ServiceResult,
	StackConfig,
	StartContext,
} from './services/types';
import { recordStartupFailure } from './startup-diagnostics';
import { createTelemetryRecorder } from './telemetry';

const SERVICE_REGISTRY: Record<ServiceName, Service> = services;

export type N8NConfig = StackConfig;

export interface N8NStack {
	baseUrl: string;
	projectName: string;
	stop: () => Promise<void>;
	containers: StartedTestContainer[];
	serviceResults: Partial<Record<ServiceName, ServiceResult>>;
	services: ServiceHelpers;
	logs: ServiceHelpers['observability']['logs'];
	metrics: ServiceHelpers['observability']['metrics'];
	findContainers: (namePattern: string | RegExp) => StartedTestContainer[];
	stopContainer: (namePattern: string | RegExp) => Promise<StoppedTestContainer | null>;
	/** Direct URLs to each main instance (bypasses load balancer). Index 0 = main-1, etc. */
	mainUrls: string[];
	startupDiagnostics: N8NStartupDiagnostics;
}

function shouldServiceStart(name: ServiceName, service: Service, ctx: StartContext): boolean {
	// Explicitly requested services always start
	if (ctx.config.services?.includes(name)) return true;
	if (service.shouldStart) {
		return service.shouldStart(ctx);
	}
	return false;
}

function groupByDependencyLevel(serviceNames: ServiceName[]): ServiceName[][] {
	const levels: ServiceName[][] = [];
	const assigned = new Set<ServiceName>();

	while (assigned.size < serviceNames.length) {
		const currentLevel: ServiceName[] = [];
		for (const name of serviceNames) {
			if (assigned.has(name)) continue;
			const service = SERVICE_REGISTRY[name];
			const deps = service?.dependsOn ?? [];
			if (deps.every((dep) => !serviceNames.includes(dep) || assigned.has(dep))) {
				currentLevel.push(name);
			}
		}
		if (currentLevel.length === 0) {
			throw new Error('Circular dependency detected in services');
		}
		levels.push(currentLevel);
		currentLevel.forEach((name) => assigned.add(name));
	}

	return levels;
}

export async function createN8NStack(config: N8NConfig = {}): Promise<N8NStack> {
	const {
		mains = 1,
		workers = 0,
		postgres: usePostgresConfig = false,
		env = {},
		projectName,
		resourceQuota,
		workerResourceQuota,
		services: enabledServices = [],
		external = false,
	} = config;

	const log = createElapsedLogger('stack');

	const isQueueMode = mains > 1 || workers > 0;
	const needsLoadBalancer = mains > 1;
	const usePostgres = usePostgresConfig || isQueueMode || enabledServices.includes('keycloak');
	const uniqueProjectName = projectName ?? `n8n-stack-${Math.random().toString(36).substring(7)}`;

	let allocatedMainPort: number | undefined;
	let allocatedLbPort: number | undefined;

	if (needsLoadBalancer) {
		allocatedLbPort = await getPort();
	} else {
		allocatedMainPort = await getPort();
	}

	const containers: StartedTestContainer[] = [];
	const serviceResults: Record<string, ServiceResult> = {};
	let environment: Record<string, string> = {};

	log(`Starting: ${uniqueProjectName}`);

	const telemetry = createTelemetryRecorder(config);

	let network: StartedNetwork;
	try {
		const networkStart = performance.now();
		network = await new Network().start();
		telemetry.recordNetwork(Math.round(performance.now() - networkStart));
	} catch (error) {
		const message = error instanceof Error ? error.message : String(error);
		telemetry.flush(false, `Network creation failed: ${message}`);
		throw error;
	}

	try {
		const ctx: StartContext = {
			config: { ...config, postgres: usePostgres },
			projectName: uniqueProjectName,
			mains,
			workers,
			isQueueMode,
			usePostgres,
			needsLoadBalancer,
			external,
			environment,
			serviceResults,
			allocatedPorts: {
				main: allocatedMainPort,
				loadBalancer: allocatedLbPort,
			},
		};

		// Step 1: Start services sequentially within each dependency level.
		// Sequential is intentional: parallel start on 2-vCPU CI runners thrashes CPU during
		// each container's JIT/init spike and pushes services past their startup timeouts.
		// Local benchmarks showed individual containers booting 2-4× faster sequentially under
		// contention, with only modest wall-clock cost on uncontended hardware.
		const allServiceNames = Object.keys(SERVICE_REGISTRY) as ServiceName[];
		const servicesToStart = allServiceNames.filter((name) =>
			shouldServiceStart(name, SERVICE_REGISTRY[name], ctx),
		);
		const dependencyLevels = groupByDependencyLevel(servicesToStart);

		const startService = async (name: ServiceName) => {
			const service = SERVICE_REGISTRY[name];
			const options = service.getOptions?.(ctx);
			const serviceStart = performance.now();
			try {
				const result = await service.start(network, uniqueProjectName, options, ctx);
				telemetry.recordService(name, Math.round(performance.now() - serviceStart));
				return { name, service, result };
			} catch (error) {
				telemetry.recordService(name, Math.round(performance.now() - serviceStart));
				const message = error instanceof Error ? error.message : String(error);
				throw new Error(`Service "${service.description}" (${name}) failed to start: ${message}`);
			}
		};

		for (const level of dependencyLevels) {
			const levelNames = level.map((name) => SERVICE_REGISTRY[name].description).join(', ');

			const results: Array<Awaited<ReturnType<typeof startService>>> = [];
			for (const name of level) {
				results.push(await startService(name));
			}

			for (const { name, service, result } of results) {
				// Some services (e.g., tracing) return multiple containers
				const serviceContainers =
					'containers' in result && Array.isArray(result.containers)
						? (result.containers as StartedTestContainer[])
						: [result.container];
				containers.push(...serviceContainers);
				serviceResults[name] = result;

				if (service.env) {
					environment = { ...environment, ...service.env(result) };
				}
				if (service.extraEnv) {
					environment = { ...environment, ...service.extraEnv(result) };
				}
			}

			ctx.environment = environment;
			ctx.serviceResults = serviceResults;

			log(`Services ready: ${levelNames}`);
		}

		// Step 2: Start n8n (main 1 first for DB setup, then rest in parallel)
		const lbResult = serviceResults.loadBalancer as LoadBalancerResult | undefined;
		const baseUrl = lbResult?.meta.baseUrl ?? `http://localhost:${allocatedMainPort}`;

		const filesToMount: FileToMount[] = Object.values(serviceResults).flatMap((result) => {
			const meta = result.meta as { n8nFilesToMount?: FileToMount[] } | undefined;
			return meta?.n8nFilesToMount ?? [];
		});

		const n8nStartupStart = performance.now();
		const n8nResult = await createN8NInstances({
			mains,
			workers,
			projectName: uniqueProjectName,
			network,
			serviceEnvironment: environment,
			userEnvironment: env,
			usePostgres,
			baseUrl: needsLoadBalancer ? undefined : baseUrl,
			allocatedPort: needsLoadBalancer ? undefined : allocatedMainPort,
			resourceQuota,
			workerResourceQuota,
			filesToMount,
		});
		containers.push(...n8nResult.containers);
		telemetry.recordN8nStartup(
			Math.round(performance.now() - n8nStartupStart),
			n8nResult.containers.length,
		);
		log(`n8n ready: ${mains} main(s), ${workers} worker(s)`);

		if (lbResult) {
			await pollContainerHttpEndpoint(lbResult.container, '/healthz/readiness');
			log('Load balancer ready');
		}

		ctx.baseUrl = baseUrl;

		// Build direct main URLs (bypassing load balancer)
		const mainUrls: string[] = [];
		for (let i = 1; i <= mains; i++) {
			const mainNamePattern = mains > 1 ? `-n8n-main-${i}` : '-n8n';
			const mainContainer = containers.find((c) => c.getName().endsWith(mainNamePattern));
			if (mainContainer) {
				const mainPort = mainContainer.getMappedPort(5678);
				mainUrls.push(`http://localhost:${mainPort}`);
			}
		}
		log(`Direct main URLs: ${mainUrls.join(', ')}`);

		// Run verification hooks (e.g. keycloak connectivity check)
		const n8nContainers = containers.filter((c) => {
			const name = c.getName();
			return name.includes('-n8n-main-') || name.endsWith('-n8n');
		});

		const verifications: string[] = [];
		for (const name of servicesToStart) {
			const service = SERVICE_REGISTRY[name];
			if (service.verifyFromN8n && serviceResults[name]) {
				await service.verifyFromN8n(serviceResults[name], n8nContainers);
				verifications.push(service.description);
			}
		}
		if (verifications.length > 0) {
			log(`Verified: ${verifications.join(', ')}`);
		}

		await waitForNetworkQuiet();
		telemetry.flush(true);

		const helperCtx: HelperContext = {
			containers,
			findContainer: (pattern: RegExp) => containers.find((c) => pattern.test(c.getName())),
			serviceResults,
		};
		const helperCache: Partial<ServiceHelpers> = {};

		const servicesProxy = new Proxy({} as ServiceHelpers, {
			get: <K extends keyof ServiceHelpers>(
				_target: ServiceHelpers,
				prop: K,
			): ServiceHelpers[K] => {
				if (prop in helperCache) {
					return helperCache[prop]!;
				}

				const factory = (helperFactories as HelperFactories)[prop];
				if (!factory) {
					throw new Error(
						`No helper factory found for service: ${String(prop)}. ` +
							`Available helpers: ${Object.keys(helperFactories).join(', ')}`,
					);
				}

				const helper = factory(helperCtx);
				helperCache[prop] = helper;
				return helper;
			},
			has: (_target, prop) => prop in helperFactories,
			ownKeys: () => Object.keys(helperFactories),
			getOwnPropertyDescriptor: (_target, prop) => {
				if (prop in helperFactories) {
					return { enumerable: true, configurable: true };
				}
				return undefined;
			},
		});

		return {
			baseUrl,
			projectName: uniqueProjectName,
			stop: async () => await stopN8NStack(containers, network, uniqueProjectName),
			containers,
			serviceResults,
			services: servicesProxy,
			get logs() {
				return servicesProxy.observability.logs;
			},
			get metrics() {
				return servicesProxy.observability.metrics;
			},
			findContainers(namePattern: string | RegExp): StartedTestContainer[] {
				const regex = typeof namePattern === 'string' ? new RegExp(namePattern) : namePattern;
				return containers.filter((container) => regex.test(container.getName()));
			},
			async stopContainer(namePattern: string | RegExp): Promise<StoppedTestContainer | null> {
				const regex = typeof namePattern === 'string' ? new RegExp(namePattern) : namePattern;
				const container = containers.find((c) => regex.test(c.getName()));
				return container ? await container.stop() : null;
			},
			mainUrls,
			startupDiagnostics: n8nResult.diagnostics,
		};
	} catch (error) {
		const message = error instanceof Error ? error.message : String(error);
		if (error instanceof N8NStartupError) {
			recordStartupFailure(uniqueProjectName, error.diagnostics, message);
		}
		telemetry.flush(false, message);
		throw error;
	}
}

function getErrorMessage(error: unknown): string {
	if (error instanceof Error) {
		return error.message;
	}
	return String(error);
}

async function stopN8NStack(
	containers: StartedTestContainer[],
	network: StartedNetwork,
	uniqueProjectName: string,
): Promise<void> {
	const errors: Error[] = [];
	try {
		const stopPromises = containers.reverse().map(async (container) => {
			try {
				await container.stop();
			} catch (error) {
				errors.push(
					new Error(`Failed to stop container ${container.getId()}: ${getErrorMessage(error)}`),
				);
			}
		});
		await Promise.allSettled(stopPromises);

		try {
			await network.stop();
		} catch (error) {
			errors.push(
				new Error(`Failed to stop network ${network.getName()}: ${getErrorMessage(error)}`),
			);
		}

		if (errors.length > 0) {
			console.warn(
				`Some cleanup operations failed for stack ${uniqueProjectName}:`,
				errors.map((e) => e.message).join(', '),
			);
		}
	} catch (error) {
		console.error(`Critical error during cleanup for stack ${uniqueProjectName}:`, error);
		throw error;
	}
}