import { type EvmtsConfig, type ResolvedConfig } from './Config'
import { defineConfig } from './defineConfig'
import { existsSync, readFileSync } from 'fs'
import * as path from 'path'

type LoadConfig = (
	configFilePath: string,
	logger?: Pick<typeof console, 'error' | 'warn'>,
) => ResolvedConfig

export const loadConfig: LoadConfig = (configFilePath, logger = console) => {
	/**
	 * evmts.config.ts currently doesn't work for ts-plugin because it is not syncronous
	 * for now load config will load from tsconfig instead until fixed
	 */
	const tsConfigPath = path.join(configFilePath, 'tsconfig.json')
	const jsConfigPath = path.join(configFilePath, 'jsconfig.json')
	let configStr
	try {
		configStr = existsSync(jsConfigPath)
			? readFileSync(jsConfigPath, 'utf8')
			: readFileSync(tsConfigPath, 'utf8')
	} catch (error) {
		logger.error(error)
		throw new Error(
			`Failed to read the file at ${tsConfigPath}. Make sure the file exists and is accessible.`,
		)
	}
	let configJson: {
		compilerOptions: {
			plugins?: Array<{ name: '@evmts/ts-plugin' } & EvmtsConfig>
			baseUrl?: string
		}
	}
	try {
		configJson = JSON.parse(configStr)
	} catch (e) {
		logger.error(e)
		throw new Error(`tsconfig.json at ${tsConfigPath} is not valid json`)
	}

	let config: EvmtsConfig | undefined =
		configJson?.compilerOptions?.plugins?.find(
			(plugin) => plugin.name === '@evmts/ts-plugin',
		)

	if (!config) {
		logger.warn(
			'No Evmts plugin found in tsconfig.json. Using the default config',
		)
		config = {}
	}

	if (config && configJson.compilerOptions.baseUrl) {
		config = {
			...config,
			compiler: {
				...config.compiler,
				libs: [
					...(config.compiler?.libs ?? []),
					path.join(configFilePath, configJson.compilerOptions.baseUrl),
				],
			},
		}
	}

	return defineConfig(() => config ?? {}).configFn(configFilePath)
}