import { promises as fs } from 'node:fs'
import { homedir } from 'node:os'
import * as path from 'node:path'
import process from 'node:process'

export interface UserConfigPersisted {
    apiId: number
    apiHash: string
}

export function getConfigFilePath(): string {
    switch (process.platform) {
        case 'linux':
            return path.join(homedir(), '.local', 'share', 'mtcute-create.json')
        case 'darwin':
            return path.join(homedir(), 'Library', 'Application Support', 'mtcute-create.json')
        case 'win32':
            return path.join(process.env.APPDATA!, 'mtcute-create.json')
    }

    throw new Error(`Unsupported platform: ${process.platform}`)
}

export async function readConfig(): Promise<UserConfigPersisted | null> {
    const filePath = getConfigFilePath()

    try {
        const data = await fs.readFile(filePath, 'utf8')

        return JSON.parse(data) as UserConfigPersisted
    } catch (e) {
        if (e && typeof e === 'object' && 'code' in e && e.code === 'ENOENT') return null

        throw e
    }
}

export async function writeConfig(config: UserConfigPersisted): Promise<void> {
    const filePath = getConfigFilePath()

    await fs.mkdir(path.dirname(filePath), { recursive: true })
    await fs.writeFile(filePath, JSON.stringify(config, null, 2))
}