import { useState, useCallback } from 'react'
import {
  getPresetManifestEntry,
  presetToChordsData,
  presetToUploadData
} from '../utils/presetManifest'

export function useSession() {
  const [sessionId, setSessionId] = useState(null)
  const [stems, setStems] = useState([])
  const [detection, setDetection] = useState(null)
  const [chordsData, setChordsData] = useState(null)
  const [loading, setLoading] = useState(false)
  const [error, setError] = useState(null)

  const clearError = useCallback(() => {
    setError(null)
  }, [])

  const loadPreset = useCallback(async (presetName) => {
    setLoading(true)
    setError(null)

    try {
      const preset = await getPresetManifestEntry(presetName)
      if (!preset) {
        throw new Error(`Preset '${presetName}' is missing from the manifest.`)
      }

      const localSessionId = `preset:${presetName}`
      const uploadData = presetToUploadData(preset, localSessionId)

      setSessionId(localSessionId)
      setStems(uploadData.stems)
      setDetection(preset.detection)
      setChordsData(presetToChordsData(preset))

      return { upload: uploadData, detection: preset.detection }
    } catch (err) {
      setError(err.message)
      return null
    } finally {
      setLoading(false)
    }
  }, [])

  return {
    sessionId,
    stems,
    detection,
    chordsData,
    loading,
    error,
    loadPreset,
    clearError
  }
}