import fs, {readFileSync} from 'node:fs';
import path from 'node:path';
import type {LogLevel} from '@remotion/renderer';
import {RenderInternals} from '@remotion/renderer';
import {BrowserSafeApis} from '@remotion/renderer/client';
import {StudioServerInternals} from '@remotion/studio-server';
import dotenv from 'dotenv';
import {chalk} from './chalk';
import {makeHyperlink} from './hyperlinks/make-link';
import {Log} from './log';
import {parsedCli} from './parsed-cli';

const {envFileOption} = BrowserSafeApis.options;

function getProcessEnv(): Record<string, string> {
	const env: Record<string, string> = {};

	const validKeys = Object.keys(process.env).filter((key) =>
		key.startsWith('REMOTION_'),
	);

	for (const key of validKeys) {
		env[key] = process.env[key] as string;
	}

	return env;
}

const watchEnvFile = ({
	processEnv,
	envFile,
	onUpdate,
	logLevel,
}: {
	processEnv: ReturnType<typeof getProcessEnv>;
	envFile: string;
	onUpdate: (newProps: Record<string, string>) => void;
	logLevel: LogLevel;
}): (() => void) => {
	const {unwatch} = StudioServerInternals.installFileWatcher({
		file: envFile,
		onChange: async (event) => {
			try {
				if (event.type === 'deleted') {
					Log.warn({indent: false, logLevel}, `${envFile} was deleted.`);
				} else {
					onUpdate({
						...processEnv,
						...dotenv.parse(event.content),
					});
					Log.info(
						{indent: false, logLevel},
						chalk.blueBright(
							event.type === 'created'
								? `Created env file ${envFile}`
								: `Updated env file ${envFile}`,
						),
					);
				}
			} catch (err) {
				Log.error(
					{indent: false, logLevel},
					`${envFile} update failed with error ${(err as Error).stack}`,
				);
			}
		},
	});
	return unwatch;
};

const getEnvForEnvFile = ({
	processEnv,
	envFile,
	onUpdate,
	logLevel,
	indent,
}: {
	processEnv: ReturnType<typeof getProcessEnv>;
	envFile: string;
	onUpdate: null | ((newProps: Record<string, string>) => void);
	logLevel: LogLevel;
	indent: boolean;
}) => {
	try {
		const envFileData = readFileSync(envFile);
		if (onUpdate) {
			if (typeof fs.watchFile === 'undefined') {
				Log.warn(
					{indent: false, logLevel},
					'Unsupported feature (fs.watchFile): .env file will not hot reload.',
				);
			} else {
				watchEnvFile({processEnv, envFile, onUpdate, logLevel});
			}
		}

		const relativeEnvFile = path.relative(process.cwd(), envFile);
		Log.verbose(
			{indent, logLevel},
			`Loaded env file from ${makeHyperlink({fallback: envFile, text: relativeEnvFile, url: 'file://' + envFile})}.`,
		);

		return {
			...processEnv,
			...dotenv.parse(envFileData),
		};
	} catch (err) {
		Log.error(
			{indent: false, logLevel},
			`Your .env file at ${envFile} could not not be parsed.`,
		);
		Log.error({indent: false, logLevel}, err);
		process.exit(1);
	}
};

const findDotEnvFile = (
	remotionRoot: string,
): {found: string | null; defaultEnvFile: string} => {
	const defaultEnvFile = path.resolve(remotionRoot, '.env');
	const paths = [defaultEnvFile, path.resolve(remotionRoot, '.env.local')];

	for (const p of paths) {
		if (fs.existsSync(p)) {
			return {found: p, defaultEnvFile};
		}
	}

	return {found: null, defaultEnvFile};
};

export const getEnvironmentVariables = (
	onUpdate: null | ((newProps: Record<string, string>) => void),
	logLevel: LogLevel,
	indent: boolean,
): Record<string, string> => {
	const processEnv = getProcessEnv();

	const {value: envFileValue, source: envFileSource} = envFileOption.getValue({
		commandLine: parsedCli,
	});

	const remotionRoot = RenderInternals.findRemotionRoot();

	if (envFileValue && envFileSource !== 'default') {
		const baseDir = envFileSource === 'cli' ? process.cwd() : remotionRoot;
		const envFile = path.resolve(baseDir, envFileValue);
		if (!fs.existsSync(envFile)) {
			Log.error(
				{indent: false, logLevel},
				envFileSource === 'cli'
					? 'You passed a --env-file but it could not be found.'
					: 'You specified a custom .env file using `Config.setDotEnvLocation()` in the config file but it could not be found',
			);
			Log.error(
				{indent: false, logLevel},
				'We looked for the file at:',
				envFile,
			);
			Log.error(
				{indent: false, logLevel},
				'Check that your path is correct and try again.',
			);
			process.exit(1);
		}

		return getEnvForEnvFile({processEnv, envFile, onUpdate, logLevel, indent});
	}

	const {defaultEnvFile, found} = findDotEnvFile(remotionRoot);

	if (!found) {
		if (onUpdate) {
			if (typeof fs.watchFile === 'undefined') {
				Log.warn(
					{indent: false, logLevel},
					'Unsupported Bun feature: .env file will not hot reload.',
				);
			} else {
				watchEnvFile({
					processEnv,
					envFile: defaultEnvFile,
					onUpdate,
					logLevel,
				});
			}
		}

		return processEnv;
	}

	return getEnvForEnvFile({
		processEnv,
		envFile: found,
		onUpdate,
		logLevel,
		indent,
	});
};