import http from 'node:http';
import https from 'node:https';
import { execa } from 'execa';
import semver from 'semver';
import spdxLicenses from 'spdx-license-list';
import {
	type DependencyMap,
	isModuleName,
	isObject,
	type PeopleSetting,
	Project,
	toArray,
} from '@boost/common';
import { Package } from './Package';
import type { ValidateOptions } from './types';

export class PackageValidator {
	static entryPoints: string[] = ['main', 'module', 'browser', 'types', 'typings', 'bin', 'man'];

	errors: string[] = [];

	package: Package;

	warnings: string[] = [];

	constructor(pkg: Package) {
		this.package = pkg;
	}

	hasErrors(): boolean {
		return this.errors.length > 0;
	}

	hasWarnings(): boolean {
		return this.warnings.length > 0;
	}

	async validate(options: ValidateOptions) {
		const promises: Promise<unknown>[] = [];

		if (options.meta) {
			this.checkMetadata();
		}

		if (options.deps) {
			this.checkDependencies();
		}

		if (options.engines) {
			promises.push(this.checkEngines());
		}

		if (options.entries) {
			this.checkEntryPoints();
		}

		if (options.license) {
			this.checkLicense();
		}

		if (options.links) {
			promises.push(this.checkLinks());
		}

		if (options.people) {
			promises.push(this.checkPeople());
		}

		if (options.repo) {
			promises.push(this.checkRepository());
		}

		await Promise.all(promises);

		return this;
	}

	protected checkDependencies() {
		this.package.debug('Checking dependencies');

		const usesLerna = this.isLernaManaged();
		const workspacePackageNames = new Set(this.getWorkspacePackageNames());
		const {
			dependencies = {},
			devDependencies = {},
			peerDependencies = {},
			// peerDependenciesMeta = {},
			optionalDependencies = {},
		} = this.package.json;

		this.checkDependencyRange(dependencies);
		this.checkDependencyRange(devDependencies);
		this.checkDependencyRange(peerDependencies);
		this.checkDependencyRange(optionalDependencies);

		Object.entries(peerDependencies).forEach(([peerName, versionConstraint]) => {
			const devVersion = semver.coerce(devDependencies[peerName]);
			const prodVersion = dependencies[peerName];

			if (prodVersion) {
				this.errors.push(`Dependency "${peerName}" defined as both a prod and peer dependency.`);
			}

			// Avoid further checks if constraint is special.
			if (versionConstraint.includes(':')) {
				return;
			}

			// When using Lerna, we want to avoid pairing a peer with a dev dependency,
			// as Lerna will update their `package.json` version of all dependent packages!
			// This would accidently publish many packages that shouldn't be.
			if (usesLerna && workspacePackageNames.has(peerName)) {
				if (devVersion) {
					this.errors.push(
						`Peer dependency "${peerName}" should not define a dev dependency when using Lerna.`,
					);
				}

				return;
			}

			if (!devVersion) {
				// NOTE: This is useful but causes unnecessary "package changes" when using semantic
				// releases or changesets. Best approach forward?
				// if (!peerDependenciesMeta[peerName]?.optional) {
				// 	this.warnings.push(
				// 		`Peer dependency "${peerName}" is missing a version satisfying dev dependency.`,
				// 	);
				// }
			} else if (!semver.satisfies(devVersion.version, versionConstraint)) {
				this.errors.push(
					`Dev dependency "${peerName}" does not satisfy version constraint of its peer. Found ${devVersion.version}, requires ${versionConstraint}.`,
				);
			}
		});
	}

	protected checkDependencyRange(deps: DependencyMap) {
		Object.entries(deps).forEach(([depName, version]) => {
			if (version.startsWith('file:')) {
				this.errors.push(
					`Dependency "${depName}" must not require the file system. Found "file:" constraint.`,
				);
			} else if (version.startsWith('link:')) {
				this.errors.push(
					`Dependency "${depName}" must not require symlinks. Found "link:" constraint.`,
				);
			}
		});
	}

	protected async checkEngines() {
		this.package.debug('Checking engines');

		const { engines } = this.package.json;
		const nodeConstraint = engines?.node;
		const npmConstraint = engines?.npm;
		const yarnConstraint = engines?.yarn;

		if (nodeConstraint) {
			const nodeVersion = semver.coerce(await this.getBinVersion('node'));

			if (nodeVersion && !semver.satisfies(nodeVersion.version, nodeConstraint)) {
				this.warnings.push(
					`Node.js does not satisfy engine constraints. Found ${nodeVersion.version}, requires ${nodeConstraint}.`,
				);
			}
		}

		if (npmConstraint) {
			const npmVersion = semver.coerce(await this.getBinVersion('npm'));

			if (npmVersion && !semver.satisfies(npmVersion.version, npmConstraint)) {
				this.warnings.push(
					`npm does not satisfy engine constraints. Found ${npmVersion.version}, requires ${npmConstraint}.`,
				);
			}
		}

		if (yarnConstraint) {
			const yarnVersion = semver.coerce(await this.getBinVersion('yarn'));

			if (yarnVersion && !semver.satisfies(yarnVersion.version, yarnConstraint)) {
				this.warnings.push(
					`Yarn does not satisfy engine constraints. Found ${yarnVersion.version}, requires ${yarnConstraint}.`,
				);
			}
		}
	}

	protected checkEntryPoints() {
		this.package.debug('Checking entry points');

		const { bin, man, exports: exp } = this.package.json;

		PackageValidator.entryPoints.forEach((field) => {
			const relPath = this.package.json[field as 'main'];

			if (!relPath || typeof relPath !== 'string') {
				if (field === 'main' && !exp) {
					this.errors.push('Missing primary entry point. Provide a `main` or `exports` field.');
				}

				return;
			}

			if (!this.doesPathExist(relPath)) {
				this.errors.push(`Entry point "${field}" resolves to an invalid or missing file.`);
			}
		});

		if (isObject(bin)) {
			Object.entries(bin).forEach(([name, path]) => {
				if (!this.doesPathExist(path)) {
					this.errors.push(`Bin "${name}" resolves to an invalid or missing file.`);
				}
			});
		}

		if (Array.isArray(man)) {
			man.forEach((path) => {
				if (!this.doesPathExist(path)) {
					this.errors.push(`Manual "${path}" resolves to an invalid or missing file.`);
				}
			});
		}
	}

	protected checkLicense() {
		this.package.debug('Checking license');

		const { license } = this.package.json;

		if (license) {
			if (license === 'UNLICENSED') {
				return;
			}

			const spdxLicenseTypes = new Set(
				Object.keys(spdxLicenses).map((key) => key.toLocaleLowerCase()),
			);

			toArray(
				typeof license === 'string' ? { type: license, url: spdxLicenses[license] } : license,
			).forEach((l) => {
				if (!spdxLicenseTypes.has(l.type.toLocaleLowerCase())) {
					this.errors.push(`Invalid license "${l.type}". Must be an official SPDX license type.`);
				}
			});
		} else {
			this.errors.push('Missing license.');
		}

		if (!this.doesPathExist('LICENSE') && !this.doesPathExist('LICENSE.md')) {
			this.errors.push(
				'No license file found in package. Must contain one of LICENSE or LICENSE.md.',
			);
		}
	}

	protected async checkLinks() {
		this.package.debug('Checking links');

		const { bugs, homepage } = this.package.json;
		const bugsUrl = isObject(bugs) ? bugs.url : bugs;

		if (homepage && !(await this.doesUrlExist(homepage))) {
			this.warnings.push('Homepage link is invalid. URL is either malformed or upstream is down.');
		}

		if (bugsUrl && !(await this.doesUrlExist(bugsUrl))) {
			this.warnings.push('Bugs link is invalid. URL is either malformed or upstream is down.');
		}
	}

	protected checkMetadata() {
		this.package.debug('Checking metadata');

		const { name, version, description, keywords, private: isPrivate } = this.package.json;

		if (!name) {
			this.errors.push('Missing name.');
		} else if (!isModuleName(name)) {
			this.errors.push('Invalid name format. Must contain alphanumeric characters and dashes.');
		}

		// Only validate name when a private package
		if (isPrivate) {
			return;
		}

		if (!version) {
			this.errors.push('Missing version.');
		}

		if (!description) {
			this.warnings.push('Missing description.');
		}

		if (!keywords || keywords.length === 0) {
			this.warnings.push('Missing keywords.');
		}

		if (!this.doesPathExist('README') && !this.doesPathExist('README.md')) {
			this.errors.push('No read me found in package. Must contain one of README or README.md.');
		}
	}

	protected async checkPeople() {
		this.package.debug('Checking author and contributors');

		const { author, contributors } = this.package.json;

		if (!author) {
			this.warnings.push('Missing author.');
		} else if (isObject(author)) {
			if (!author.name) {
				this.errors.push('Missing author name.');
			}

			if (author.url && !(await this.doesUrlExist(author.url))) {
				this.warnings.push('Author URL is invalid. URL is either malformed or upstream is down.');
			}
		}

		if (Array.isArray(contributors)) {
			await Promise.all(
				(contributors as PeopleSetting[]).map(async (contrib) => {
					if (typeof contrib === 'string') {
						return;
					}

					if (!contrib.name) {
						this.errors.push('Missing contributor name.');
					}

					if (contrib.url && !(await this.doesUrlExist(contrib.url))) {
						this.warnings.push(
							'Contributor URL is invalid. URL is either malformed or upstream is down.',
						);
					}
				}),
			);
		} else if (contributors) {
			this.warnings.push('Contributors must be an array.');
		}
	}

	protected async checkRepository() {
		this.package.debug('Checking repository');

		const repo = this.package.json.repository;
		const url = isObject(repo) ? repo.url : repo;

		if (!url) {
			this.errors.push('Missing repository.');
		} else if (url.startsWith('http') && !(await this.doesUrlExist(url))) {
			this.warnings.push('Repository is invalid. URL is either malformed or upstream is down.');
		}

		if (isObject(repo)) {
			const dir = repo.directory;

			if (dir && !this.package.workspaceRoot.append(dir).exists()) {
				this.errors.push(`Repository directory "${dir}" does not exist.`);
			}
		}
	}

	protected doesPathExist(path: string): boolean {
		return this.package.path.append(path).exists();
	}

	// istanbul ignore next
	protected async doesUrlExist(url: string): Promise<boolean> {
		return new Promise((resolve) => {
			const request = url.startsWith('https') ? https.request : http.request;
			const ping = request(url, () => {
				resolve(true);
				ping.abort();
			});

			ping.on('error', () => {
				resolve(false);
				ping.abort();
			});

			ping.write('');
			ping.end();
		});
	}

	protected async getBinVersion(bin: string): Promise<string> {
		try {
			return (await execa(bin, ['-v'], { preferLocal: true })).stdout.trim();
		} catch {
			// istanbul ignore next
			return '';
		}
	}

	protected getWorkspacePackageNames(): string[] {
		return new Project(this.package.workspaceRoot)
			.getWorkspacePackages()
			.map((wp) => wp.package.name);
	}

	protected isLernaManaged(): boolean {
		return this.package.workspaceRoot.append('lerna.json').exists();
	}
}