import { exec } from 'child_process'
import { promisify } from 'util'
import { Env_get_required } from './env'

const execAsync = promisify(exec)

// Cache for 10 seconds
let cacheTimestamp = 0
let cachedData: StorageData | null = null

export interface StorageData {
  activeDriveUsage: number
  totalDiskCapacity: number
  totalDiskUsed: number
  availableDisk: number
}

export async function fetchStorageData(): Promise<StorageData> {
  const now = Date.now()
  
  // Return cached data if less than 10 seconds old
  if (cachedData && now - cacheTimestamp < 10000) {
    return cachedData
  }

  try {
    // Get active drive usage in bytes
    const { stdout: driveSize } = await execAsync('fctdrive drive-size')
    const activeDriveUsage = parseInt(driveSize.trim()) || 0

    // Get disk usage in bytes
    const fctdrivePath = Env_get_required('FCTDRIVE_PATH')
    const { stdout: dfOutput } = await execAsync(`df -B1 "${fctdrivePath}/blobs"`)
    
    // Parse df output - second line contains the data
    const lines = dfOutput.trim().split('\n')
    const dataLine = lines[1] // Skip header line
    const columns = dataLine.split(/\s+/)
    
    const totalDiskCapacity = parseInt(columns[1]) || 0
    const totalDiskUsed = parseInt(columns[2]) || 0
    const availableDisk = parseInt(columns[3]) || 0

    const data: StorageData = {
      activeDriveUsage,
      totalDiskCapacity,
      totalDiskUsed,
      availableDisk
    }

    // Update cache
    cachedData = data
    cacheTimestamp = now

    return data
  } catch (error) {
    console.error('Failed to fetch storage data:', error)
    
    // Return zeros on error as requested
    return {
      activeDriveUsage: 0,
      totalDiskCapacity: 0,
      totalDiskUsed: 0,
      availableDisk: 0
    }
  }
}