import { existsSync, readFileSync } from 'node:fs';
import { extname } from 'node:path';
import { pathToFileURL } from 'node:url';
import { resolveEnvFilePath, IMPORT_HOOK_EXTENSIONS, isPromise } from './utils.js';
import { checkIfTypescriptSupported } from './loaders/typescript.js';
/**
 * Gets the environment vars from an env file
 */
export async function getEnvFileVars(envFilePath) {
    const absolutePath = resolveEnvFilePath(envFilePath);
    if (!existsSync(absolutePath)) {
        const pathError = new Error(`Invalid env file path (${envFilePath}).`);
        pathError.name = 'PathError';
        throw pathError;
    }
    // Get the file extension
    const ext = extname(absolutePath).toLowerCase();
    let env;
    if (IMPORT_HOOK_EXTENSIONS.includes(ext)) {
        if (/tsx?$/.test(ext))
            checkIfTypescriptSupported();
        // For some reason in ES Modules, only JSON file types need to be specifically delinated when importing them
        let attributeTypes = {};
        if (ext === '.json') {
            attributeTypes = { with: { type: 'json' } };
        }
        const res = await import(pathToFileURL(absolutePath).href, attributeTypes);
        if (typeof res === 'object' && res && 'default' in res) {
            env = res.default;
        }
        else {
            env = res;
        }
        // Check to see if the imported value is a promise
        if (isPromise(env)) {
            env = await env;
        }
        return normalizeEnvObject(env, absolutePath);
    }
    const file = readFileSync(absolutePath, { encoding: 'utf8' });
    switch (ext) {
        // other loaders can be added here
        default:
            return parseEnvString(file);
    }
}
/**
 * Parse out all env vars from a given env file string and return an object
 */
export function parseEnvString(envFileString) {
    // First thing we do is stripe out all comments
    envFileString = stripComments(envFileString);
    // Next we stripe out all the empty lines
    envFileString = stripEmptyLines(envFileString);
    // Merge the file env vars with the current process env vars (the file vars overwrite process vars)
    return parseEnvVars(envFileString);
}
/**
 * Parse out all env vars from an env file string
 */
export function parseEnvVars(envString) {
    const envParseRegex = /^((.+?)[=](.*))$/gim;
    const matches = {};
    let match;
    while ((match = envParseRegex.exec(envString)) !== null) {
        // Note: match[1] is the full env=var line
        const key = match[2].trim();
        let value = match[3].trim();
        // if the string is quoted, remove everything after the final
        // quote. This implicitly removes inline comments.
        if (value.startsWith("'") || value.startsWith('"')) {
            value = value.slice(1, value.lastIndexOf(value[0]));
        }
        else {
            // if the string is not quoted, we need to explicitly remove
            // inline comments.
            value = value.split('#')[0].trim();
        }
        value = value.replace(/\\n/g, '\n');
        matches[key] = value;
    }
    return JSON.parse(JSON.stringify(matches));
}
/**
 * Strips out comments from env file string
 */
export function stripComments(envString) {
    const commentsRegex = /(^\s*#.*$)/gim;
    return envString.replace(commentsRegex, '');
}
/**
 * Strips out newlines from env file string
 */
export function stripEmptyLines(envString) {
    const emptyLinesRegex = /(^\n)/gim;
    return envString.replace(emptyLinesRegex, '');
}
/**
 * If we load data from a file like .js, the user
 * might export something which is not an object.
 *
 * This function ensures that the input is valid,
 * and converts the object's values to strings, for
 * consistincy. See issue #125 for details.
 */
export function normalizeEnvObject(input, absolutePath) {
    if (typeof input !== 'object' || !input) {
        throw new Error(`env-cmd cannot load “${absolutePath}” because it does not export an object.`);
    }
    const env = {};
    for (const [key, value] of Object.entries(input)) {
        // we're intentionally stringifying the value here, to
        // match what `child_process.spawn` does when loading
        // env variables.
        // eslint-disable-next-line @typescript-eslint/restrict-template-expressions
        env[key] = `${value}`;
    }
    return env;
}