frontend/src/components/FileUpload.jsx

import React, { useState, useCallback, useEffect } from 'react'

/* Upload slots — hidden
const STEM_TYPES = [
  { name: 'guitar', label: 'Guitar', icon: '🎸' },
  { name: 'drums', label: 'Drums', icon: '🥁' },
  { name: 'bass', label: 'Bass', icon: '🎸' },
  { name: 'synth', label: 'Synth', icon: '🎹' },
  { name: 'click_record', label: 'Click Record', icon: '⏱️' }
]
*/

function FileUpload({ onUpload, onLoadPreset, loading, error, onClearError, cacheStatus = {} }) {
  const [presets, setPresets] = useState([])
  const [selectedPreset, setSelectedPreset] = useState('')

  useEffect(() => {
    fetch('/api/presets')
      .then(r => r.json())
      .then(data => setPresets(data.presets || []))
      .catch(() => {})
  }, [])

  /* Upload slots — hidden
  const [stems, setStems] = useState({
    guitar: null,
    drums: null,
    bass: null,
    synth: null,
    click_record: null
  })
  const [midiFiles, setMidiFiles] = useState([])
  const [midiDragActive, setMidiDragActive] = useState(false)

  const handleStemSelect = useCallback((stemType, file) => {
    setStems(prev => ({ ...prev, [stemType]: file }))
  }, [])

  const handleStemRemove = useCallback((stemType) => {
    setStems(prev => ({ ...prev, [stemType]: null }))
  }, [])

  const handleMidiSelect = useCallback((e) => {
    const selectedFiles = Array.from(e.target.files).filter(f =>
      f.name.toLowerCase().endsWith('.mid') || f.name.toLowerCase().endsWith('.midi')
    )
    setMidiFiles(prev => [...prev, ...selectedFiles])
  }, [])

  const handleMidiRemove = useCallback((index) => {
    setMidiFiles(prev => prev.filter((_, i) => i !== index))
  }, [])

  const handleMidiDrag = useCallback((e) => {
    e.preventDefault()
    e.stopPropagation()
    if (e.type === 'dragenter' || e.type === 'dragover') {
      setMidiDragActive(true)
    } else if (e.type === 'dragleave') {
      setMidiDragActive(false)
    }
  }, [])

  const handleMidiDrop = useCallback((e) => {
    e.preventDefault()
    e.stopPropagation()
    setMidiDragActive(false)

    const droppedFiles = Array.from(e.dataTransfer.files).filter(f =>
      f.name.toLowerCase().endsWith('.mid') || f.name.toLowerCase().endsWith('.midi')
    )
    setMidiFiles(prev => [...prev, ...droppedFiles])
  }, [])

  const handleSubmit = useCallback(async () => {
    const formData = new FormData()
    Object.entries(stems).forEach(([name, file]) => {
      if (file) formData.append(name, file)
    })
    midiFiles.forEach(file => {
      formData.append('midi', file)
    })
    await onUpload(formData)
  }, [stems, midiFiles, onUpload])

  const stemCount = Object.values(stems).filter(f => f !== null).length
  const hasFiles = stemCount > 0
  */

  return (
    <div className="glass rounded-2xl p-6 animate-fade-in max-w-4xl mx-auto">
      <h2 className="text-xl font-semibold mb-6 text-center">Load a Demo Track</h2>

      {/* Demo presets dropdown */}
      {presets.length > 0 && (
        <div className="p-4 bg-gray-800/50 rounded-xl border border-gray-600">
          <div className="flex gap-3">
            <select
              value={selectedPreset}
              onChange={(e) => setSelectedPreset(e.target.value)}
              disabled={loading}
              className="flex-1 bg-gray-800 border border-gray-600 rounded-lg px-3 py-2 text-white text-sm focus:outline-none focus:border-primary-500"
            >
              <option value="">Select a demo...</option>
              {presets.map(p => {
                const status = cacheStatus[p]
                const label = status === 'cached'
                  ? `${p} ✓`
                  : status === 'loading'
                    ? `${p} …`
                    : p
                return <option key={p} value={p}>{label}</option>
              })}
            </select>
            <button
              onClick={() => selectedPreset && onLoadPreset(selectedPreset)}
              disabled={loading || !selectedPreset}
              className="px-4 py-2 rounded-lg text-sm font-medium transition-all disabled:bg-gray-700 disabled:text-gray-500 disabled:cursor-not-allowed bg-gradient-to-r from-primary-600 to-accent-600 hover:from-primary-500 hover:to-accent-500"
            >
              {loading ? 'Loading...' : 'Load'}
            </button>
          </div>
        </div>
      )}

      {/* Upload slots — hidden
      <div className="grid grid-cols-2 gap-4 mb-6">
        {STEM_TYPES.map(({ name, label, icon }) => (
          <StemUploadCard
            key={name}
            name={name}
            label={label}
            icon={icon}
            file={stems[name]}
            onSelect={(file) => handleStemSelect(name, file)}
            onRemove={() => handleStemRemove(name)}
            disabled={loading}
          />
        ))}
      </div>

      <div
        onDragEnter={handleMidiDrag}
        onDragLeave={handleMidiDrag}
        onDragOver={handleMidiDrag}
        onDrop={handleMidiDrop}
        className={`
          mt-6 p-4 border-2 border-dashed rounded-xl transition-all
          ${midiDragActive
            ? 'border-blue-500 bg-blue-500/10'
            : 'border-gray-600'
          }
        `}
      >
        <div className="flex items-center justify-between mb-3">
          <div className="flex items-center gap-2">
            <span className="text-2xl">🎹</span>
            <span className="font-medium text-gray-300">MIDI Files (Optional)</span>
          </div>
          <label
            htmlFor="midi-input"
            className="px-4 py-2 bg-gray-700 hover:bg-gray-600 rounded-lg cursor-pointer transition-colors text-sm"
          >
            + Add MIDI
          </label>
          <input
            type="file"
            multiple
            accept=".mid,.midi"
            onChange={handleMidiSelect}
            className="hidden"
            id="midi-input"
            disabled={loading}
          />
        </div>

        {midiFiles.length > 0 && (
          <div className="space-y-2">
            {midiFiles.map((file, index) => (
              <div
                key={index}
                className="flex items-center justify-between bg-gray-800/50 rounded-lg px-3 py-2"
              >
                <div className="flex items-center gap-2">
                  <span className="text-sm truncate">{file.name}</span>
                  <span className="text-xs text-gray-500">
                    {(file.size / 1024).toFixed(1)} KB
                  </span>
                </div>
                <button
                  onClick={() => handleMidiRemove(index)}
                  className="text-gray-400 hover:text-red-400 transition-colors"
                  disabled={loading}
                >
                  ✕
                </button>
              </div>
            ))}
          </div>
        )}
      </div>

      <button
        onClick={handleSubmit}
        disabled={loading || !hasFiles}
        className={`
          w-full mt-6 py-3 rounded-xl font-medium transition-all
          ${loading || !hasFiles
            ? 'bg-gray-600 cursor-not-allowed'
            : 'bg-gradient-to-r from-primary-600 to-accent-600 hover:from-primary-500 hover:to-accent-500'
          }
        `}
      >
        {loading ? (
          <span className="flex items-center justify-center gap-2">
            <span className="animate-spin">⏳</span>
            Analyzing...
          </span>
        ) : (
          `Upload ${stemCount} Stem${stemCount !== 1 ? 's' : ''}${midiFiles.length > 0 ? ` + ${midiFiles.length} MIDI` : ''}`
        )}
      </button>
      */}

      {/* Error display */}
      {error && (
        <div className="mt-4 p-3 bg-red-500/20 border border-red-500/50 rounded-lg text-red-300 text-sm flex items-center justify-between">
          <span>{error}</span>
          <button
            onClick={onClearError}
            className="text-red-400 hover:text-red-200"
          >
            ✕
          </button>
        </div>
      )}
    </div>
  )
}

/* StemUploadCard — hidden
function StemUploadCard({ name, label, icon, file, onSelect, onRemove, disabled }) {
  const [dragActive, setDragActive] = React.useState(false)

  const handleFileChange = (e) => {
    const selectedFile = e.target.files[0]
    if (selectedFile && selectedFile.name.toLowerCase().endsWith('.wav')) {
      onSelect(selectedFile)
    }
  }

  const handleDrag = (e) => {
    e.preventDefault()
    e.stopPropagation()
    if (e.type === 'dragenter' || e.type === 'dragover') {
      setDragActive(true)
    } else if (e.type === 'dragleave') {
      setDragActive(false)
    }
  }

  const handleDrop = (e) => {
    e.preventDefault()
    e.stopPropagation()
    setDragActive(false)

    const droppedFile = e.dataTransfer.files[0]
    if (droppedFile && droppedFile.name.toLowerCase().endsWith('.wav')) {
      onSelect(droppedFile)
    }
  }

  return (
    <div
      onDragEnter={handleDrag}
      onDragLeave={handleDrag}
      onDragOver={handleDrag}
      onDrop={handleDrop}
      className={`
        p-4 rounded-xl border-2 transition-all
        ${file
          ? 'border-green-500 bg-green-500/10'
          : dragActive
            ? 'border-blue-500 bg-blue-500/10'
            : 'border-gray-600 hover:border-primary-500 bg-gray-800/30'
        }
      `}
    >
      <div className="flex items-center justify-between mb-3">
        <div className="flex items-center gap-2">
          <span className="text-2xl">{icon}</span>
          <span className="font-medium text-gray-300">{label}</span>
        </div>
        {file && (
          <button
            onClick={onRemove}
            className="text-gray-400 hover:text-red-400 transition-colors"
            disabled={disabled}
          >
            ✕
          </button>
        )}
      </div>

      {file ? (
        <div className="text-sm">
          <p className="text-gray-300 truncate">{file.name}</p>
          <p className="text-gray-500 text-xs mt-1">
            {(file.size / 1024 / 1024).toFixed(1)} MB
          </p>
        </div>
      ) : (
        <label
          htmlFor={`${name}-input`}
          className="block w-full py-2 text-center bg-gray-700 hover:bg-gray-600 rounded-lg cursor-pointer transition-colors text-sm"
        >
          Select File
        </label>
      )}

      <input
        type="file"
        accept=".wav"
        onChange={handleFileChange}
        className="hidden"
        id={`${name}-input`}
        disabled={disabled}
      />
    </div>
  )
}
*/

export default FileUpload