import { tmpdir } from 'node:os'
import { writeFile, rm } from 'node:fs/promises'
import { join } from 'node:path'

import ffmpeg from 'fluent-ffmpeg'

export type MediaMetadata = {
  durationInSec: number
  durationInMs: number
  hasAudio: boolean
}

/**
 * Get the media info of a base64 or file path
 * @param input
 * @returns
 */
export async function getMediaInfo(input: string): Promise<MediaMetadata> {
  // If the input is a base64 string
  if (input.startsWith('data:')) {
    // Extract the base64 content
    // Extract the base64 content
    const [head, tail] = input.split(';base64,')
    if (!tail) {
      throw new Error('Invalid base64 data')
    }

    const extension = head.split('/').pop() || ''
    const base64Content = tail || ''

    // Decode the base64 content to a buffer
    const buffer = Buffer.from(base64Content, 'base64')

    // Generate a temporary file name
    const tempFileName = join(tmpdir(), `temp-media-${Date.now()}.${extension}`)

    // Write the buffer to a temporary file
    await writeFile(tempFileName, buffer)

    // Get metadata from the temporary file then delete the file
    try {
      return await getMetaDataFromPath(tempFileName)
    } finally {
      await rm(tempFileName)
    }
  }

  // If the input is a path to the file
  return await getMetaDataFromPath(input)
}

async function getMetaDataFromPath(filePath: string): Promise<MediaMetadata> {
  return new Promise((resolve, reject) => {
    ffmpeg.ffprobe(filePath, (err, metadata) => {
      let results = {
        durationInSec: 0,
        durationInMs: 0,
        hasAudio: false,
      }

      if (err) {
        console.error(
          'getMediaInfo(): failed to analyze the source (might happen with empty files)',
          err
        )
        // reject(err);
        resolve(results)
        return
      }

      try {
        results.durationInSec = metadata?.format?.duration || 0
        results.durationInMs = results.durationInSec * 1000
        results.hasAudio = (metadata?.streams || []).some(
          (stream) => stream.codec_type === 'audio'
        )
      } catch (err) {
        console.error(
          `getMediaInfo(): failed to analyze the source (might happen with empty files)`,
          err
        )
        results.durationInSec = 0
        results.durationInMs = 0
        results.hasAudio = false
      }
      resolve(results)
    })
  })
}