import { useState, useEffect } from 'react'
import { Save, Download, Upload, Trash2, Plus, Check, Pencil, X, LogOut, Shield, Key, BarChart3 } from 'lucide-react'
import { useProfile } from '../context/ProfileContext'
import { useAuth } from '../context/AuthContext'
import { Avatar } from './ProfileSelect'
import { api } from '../utils/api'
import AdminPanel from './AdminPanel'
import FeatureUsageOverview from '../components/FeatureUsageOverview'
import UsageBadge from '../components/UsageBadge'

const COLORS = ['#1D9E75','#378ADD','#D85A30','#EF9F27','#7F77DD','#D4537E','#639922','#888780']

function ProfileForm({ profile, onSave, onCancel, title }) {
  const [form, setForm] = useState({
    name:         profile?.name         || '',
    sex:          profile?.sex          || 'm',
    dob:          profile?.dob          || '',
    height:       profile?.height       || '',
    goal_weight:  profile?.goal_weight  || '',
    goal_bf_pct:  profile?.goal_bf_pct  || '',
    avatar_color: profile?.avatar_color || COLORS[0],
  })
  const set = (k,v) => setForm(f=>({...f,[k]:v}))

  return (
    <div style={{background:'var(--surface2)',borderRadius:10,padding:14,marginTop:8,
      border:'1.5px solid var(--accent)'}}>
      {title && <div style={{fontWeight:600,fontSize:14,marginBottom:12,color:'var(--accent)'}}>{title}</div>}

      <div className="form-row">
        <label className="form-label">Name</label>
        <input type="text" className="form-input" value={form.name}
          onChange={e=>set('name',e.target.value)} autoFocus/>
        <span className="form-unit"/>
      </div>

      <div style={{marginBottom:12}}>
        <div style={{fontSize:12,color:'var(--text3)',marginBottom:8}}>Avatar-Farbe</div>
        <div style={{display:'flex',gap:8,alignItems:'center'}}>
          <Avatar profile={{...form}} size={36}/>
          <div style={{display:'flex',gap:6,flexWrap:'wrap'}}>
            {COLORS.map(c=>(
              <div key={c} onClick={()=>set('avatar_color',c)}
                style={{width:26,height:26,borderRadius:'50%',background:c,cursor:'pointer',
                  border:`3px solid ${form.avatar_color===c?'white':'transparent'}`,
                  boxShadow:form.avatar_color===c?`0 0 0 2px ${c}`:'none'}}/>
            ))}
          </div>
        </div>
      </div>

      <div className="form-row">
        <label className="form-label">Geschlecht</label>
        <select className="form-select" value={form.sex} onChange={e=>set('sex',e.target.value)}>
          <option value="m">Männlich</option>
          <option value="f">Weiblich</option>
        </select>
      </div>
      <div className="form-row">
        <label className="form-label">Geburtsdatum</label>
        <input type="date" className="form-input" style={{width:140}} value={form.dob||''}
          onChange={e=>set('dob',e.target.value)}/>
        <span className="form-unit"/>
      </div>
      <div className="form-row">
        <label className="form-label">Größe</label>
        <input type="number" className="form-input" min={100} max={250} value={form.height||''}
          onChange={e=>set('height',e.target.value)}/>
        <span className="form-unit">cm</span>
      </div>
      <div style={{fontSize:11,fontWeight:600,color:'var(--text3)',textTransform:'uppercase',
        letterSpacing:'0.04em',margin:'10px 0 6px'}}>Ziele (optional)</div>
      <div className="form-row">
        <label className="form-label">Zielgewicht</label>
        <input type="number" className="form-input" min={30} max={300} step={0.1}
          value={form.goal_weight||''} onChange={e=>set('goal_weight',e.target.value)} placeholder="–"/>
        <span className="form-unit">kg</span>
      </div>
      <div className="form-row">
        <label className="form-label">Ziel-KF%</label>
        <input type="number" className="form-input" min={3} max={50} step={0.1}
          value={form.goal_bf_pct||''} onChange={e=>set('goal_bf_pct',e.target.value)} placeholder="–"/>
        <span className="form-unit">%</span>
      </div>
      <div style={{display:'flex',gap:8,marginTop:12}}>
        <button className="btn btn-primary" style={{flex:1}} onClick={()=>onSave(form)}>
          <Save size={13}/> Speichern
        </button>
        <button className="btn btn-secondary" style={{flex:1}} onClick={onCancel}>
          <X size={13}/> Abbrechen
        </button>
      </div>
    </div>
  )
}

export default function SettingsPage() {
  const { profiles, activeProfile, setActiveProfile, refreshProfiles } = useProfile()
  const { logout, isAdmin, canExport } = useAuth()
  const [adminOpen, setAdminOpen] = useState(false)
  const [pinOpen,   setPinOpen]   = useState(false)
  const [newPin,    setNewPin]    = useState('')
  const [pinMsg,    setPinMsg]    = useState(null)
  const [exportUsage, setExportUsage] = useState(null)  // Phase 3: Usage badge

  // Load feature usage for export badges
  useEffect(() => {
    api.getFeatureUsage().then(features => {
      const exportFeature = features.find(f => f.feature_id === 'data_export')
      setExportUsage(exportFeature)
    }).catch(err => console.error('Failed to load usage:', err))
  }, [])

  const handleLogout = async () => {
    if (!confirm('Ausloggen?')) return
    await logout()
  }

  const handlePinChange = async () => {
    if (newPin.length < 4) return setPinMsg('Mind. 4 Zeichen')
    try {
      const token = localStorage.getItem('bodytrack_token')||''
      const pid   = localStorage.getItem('bodytrack_active_profile')||''
      const r = await fetch('/api/auth/pin', {
        method:'PUT',
        headers:{'Content-Type':'application/json','X-Auth-Token':token,'X-Profile-Id':pid},
        body: JSON.stringify({pin: newPin})
      })
      if (!r.ok) throw new Error('Fehler')
      setNewPin(''); setPinMsg('✓ PIN geändert')
      setTimeout(()=>setPinMsg(null), 2000)
    } catch(e) { setPinMsg('Fehler beim Speichern') }
  }
  // editingId: string ID of profile being edited, or 'new' for new profile, or null
  const [editingId,  setEditingId]  = useState(null)
  const [saved,      setSaved]      = useState(false)
  const [importing,  setImporting]  = useState(false)
  const [importMsg,  setImportMsg]  = useState(null)

  const handleImport = async (e) => {
    const file = e.target.files?.[0]
    if (!file) return

    if (!confirm(`Backup "${file.name}" importieren? Vorhandene Einträge werden nicht überschrieben.`)) {
      e.target.value = '' // Reset file input
      return
    }

    setImporting(true)
    setImportMsg(null)

    try {
      const formData = new FormData()
      formData.append('file', file)

      const token = localStorage.getItem('bodytrack_token')||''
      const pid   = localStorage.getItem('bodytrack_active_profile')||''

      const res = await fetch('/api/import/zip', {
        method: 'POST',
        headers: {
          'X-Auth-Token': token,
          'X-Profile-Id': pid
        },
        body: formData
      })

      const data = await res.json()

      if (!res.ok) {
        throw new Error(data.detail || 'Import fehlgeschlagen')
      }

      // Show success message with stats
      const stats = data.stats
      const lines = []
      if (stats.weight > 0)         lines.push(`${stats.weight} Gewicht`)
      if (stats.circumferences > 0) lines.push(`${stats.circumferences} Umfänge`)
      if (stats.caliper > 0)        lines.push(`${stats.caliper} Caliper`)
      if (stats.nutrition > 0)      lines.push(`${stats.nutrition} Ernährung`)
      if (stats.activity > 0)       lines.push(`${stats.activity} Aktivität`)
      if (stats.photos > 0)         lines.push(`${stats.photos} Fotos`)
      if (stats.insights > 0)       lines.push(`${stats.insights} KI-Analysen`)

      setImportMsg({
        type: 'success',
        text: `✓ Import erfolgreich: ${lines.join(', ')}`
      })

      // Refresh data (in case new entries were added)
      await refreshProfiles()

    } catch (err) {
      setImportMsg({
        type: 'error',
        text: `✗ ${err.message}`
      })
    } finally {
      setImporting(false)
      e.target.value = '' // Reset file input
      setTimeout(() => setImportMsg(null), 5000)
    }
  }

  const handleSave = async (form, profileId) => {
    const data = {}
    if (form.name)         data.name         = form.name
    if (form.sex)          data.sex          = form.sex
    if (form.dob)          data.dob          = form.dob
    if (form.height)       data.height       = parseFloat(form.height)
    if (form.avatar_color) data.avatar_color = form.avatar_color
    if (form.goal_weight)  data.goal_weight  = parseFloat(form.goal_weight)
    if (form.goal_bf_pct)  data.goal_bf_pct  = parseFloat(form.goal_bf_pct)

    if (profileId === 'new') {
      const p = await api.createProfile({ ...data, name: form.name || 'Neues Profil' })
      await refreshProfiles()
      // Don't auto-switch – just close the form
    } else {
      await api.updateProfile(profileId, data)
      await refreshProfiles()
      // If editing active profile, update it
      if (profileId === activeProfile?.id) {
        const updated = profiles.find(p => p.id === profileId)
        if (updated) setActiveProfile({...updated, ...data})
      }
    }
    setEditingId(null)
    setSaved(true)
    setTimeout(() => setSaved(false), 2000)
  }

  const handleDelete = async (id) => {
    if (!confirm('Profil und ALLE zugehörigen Daten unwiderruflich löschen?')) return
    await api.deleteProfile(id)
    await refreshProfiles()
    if (activeProfile?.id === id) {
      const remaining = profiles.filter(p => p.id !== id)
      if (remaining.length) setActiveProfile(remaining[0])
    }
    setEditingId(null)
  }

  return (
    <div>
      <h1 className="page-title">Einstellungen</h1>

      {/* Profile list */}
      <div className="card section-gap">
        <div className="card-title">Profile ({profiles.length})</div>

        {profiles.map(p => (
          <div key={p.id}>
            <div style={{display:'flex',alignItems:'center',gap:10,padding:'10px 0',
              borderBottom:'1px solid var(--border)'}}>
              <Avatar profile={p} size={40}/>
              <div style={{flex:1}}>
                <div style={{fontSize:14,fontWeight:600}}>{p.name}</div>
                <div style={{fontSize:11,color:'var(--text3)'}}>
                  {p.sex==='m'?'Männlich':'Weiblich'}
                  {p.height ? ` · ${p.height} cm` : ''}
                  {p.goal_weight ? ` · Ziel: ${p.goal_weight} kg` : ''}
                </div>
              </div>
              <div style={{display:'flex',gap:6,alignItems:'center'}}>
                {activeProfile?.id === p.id
                  ? <span style={{fontSize:11,color:'var(--accent)',fontWeight:600,padding:'3px 8px',
                      background:'var(--accent-light)',borderRadius:6}}>Aktiv</span>
                  : <button className="btn btn-secondary" style={{padding:'4px 10px',fontSize:12}}
                      onClick={handleLogout}>
                      Nutzer wechseln
                    </button>
                }
                <button className="btn btn-secondary" style={{padding:'4px 8px'}}
                  onClick={()=>setEditingId(editingId===p.id ? null : p.id)}>
                  <Pencil size={12}/>
                </button>
                {profiles.length > 1 && (
                  <button className="btn btn-danger" style={{padding:'4px 8px'}}
                    onClick={()=>handleDelete(p.id)}>
                    <Trash2 size={12}/>
                  </button>
                )}
              </div>
            </div>

            {/* Edit form – only shown for THIS profile */}
            {editingId === p.id && (
              <ProfileForm
                profile={p}
                onSave={(form) => handleSave(form, p.id)}
                onCancel={() => setEditingId(null)}
              />
            )}
          </div>
        ))}

        {/* New profile */}
        {editingId === 'new' ? (
          <ProfileForm
            title="Neues Profil"
            onSave={(form) => handleSave(form, 'new')}
            onCancel={() => setEditingId(null)}
          />
        ) : (
          <button className="btn btn-secondary btn-full" style={{marginTop:12}}
            onClick={() => setEditingId('new')}>
            <Plus size={14}/> Neues Profil anlegen
          </button>
        )}
      </div>

      {/* Auth actions */}
      <div className="card section-gap">
        <div className="card-title">🔐 Konto</div>
        <div style={{display:'flex',gap:8,flexDirection:'column'}}>
          <button className="btn btn-secondary btn-full"
            onClick={()=>setPinOpen(o=>!o)}
            style={{display:'flex',alignItems:'center',gap:8,justifyContent:'center'}}>
            <Key size={14}/> PIN / Passwort ändern
          </button>
          {pinOpen && (
            <div style={{padding:12,background:'var(--surface2)',borderRadius:8}}>
              <div style={{display:'flex',gap:8}}>
                <input type="password" className="form-input" placeholder="Neue PIN/Passwort"
                  value={newPin} onChange={e=>setNewPin(e.target.value)} style={{flex:1}}/>
                <button className="btn btn-primary" onClick={handlePinChange}>Setzen</button>
              </div>
              {pinMsg && <div style={{fontSize:12,color:pinMsg.startsWith('✓')?'var(--accent)':'#D85A30',marginTop:6}}>{pinMsg}</div>}
            </div>
          )}
          <button className="btn btn-secondary btn-full"
            onClick={handleLogout}
            style={{display:'flex',alignItems:'center',gap:8,justifyContent:'center',color:'var(--warn)'}}>
            <LogOut size={14}/> Ausloggen
          </button>
        </div>
      </div>

      {/* Feature Usage Overview (Phase 3) */}
      <div className="card section-gap">
        <div className="card-title" style={{display:'flex',alignItems:'center',gap:6}}>
          <BarChart3 size={15} color="var(--accent)"/> Kontingente
        </div>
        <p style={{fontSize:13,color:'var(--text2)',marginBottom:12,lineHeight:1.6}}>
          Übersicht über deine Feature-Nutzung und verfügbare Kontingente.
        </p>
        <FeatureUsageOverview />
      </div>

      {/* Admin Panel */}
      {isAdmin && (
        <div className="card section-gap">
          <div style={{display:'flex',alignItems:'center',justifyContent:'space-between'}}>
            <div className="card-title" style={{margin:0,display:'flex',alignItems:'center',gap:6}}>
              <Shield size={15} color="var(--accent)"/> Admin
            </div>
            <button className="btn btn-secondary" style={{fontSize:12}}
              onClick={()=>setAdminOpen(o=>!o)}>
              {adminOpen?'Schließen':'Öffnen'}
            </button>
          </div>
          {adminOpen && <div style={{marginTop:12}}><AdminPanel/></div>}
        </div>
      )}

      {/* Export */}
      <div className="card section-gap">
        <div className="card-title">Daten exportieren</div>
        <p style={{fontSize:13,color:'var(--text2)',marginBottom:12,lineHeight:1.6}}>
          Exportiert alle Daten von <strong>{activeProfile?.name}</strong>:
          Gewicht, Umfänge, Caliper, Ernährung, Aktivität und KI-Auswertungen.
        </p>
        <div style={{display:'flex',flexDirection:'column',gap:8}}>
          {!canExport && (
            <div style={{padding:'10px 12px',background:'#FCEBEB',borderRadius:8,
              fontSize:13,color:'#D85A30',marginBottom:8}}>
              🔒 Export ist für dein Profil nicht freigeschaltet. Bitte den Admin kontaktieren.
            </div>
          )}
          {canExport && <>
            <button className="btn btn-primary btn-full"
              onClick={()=>api.exportZip()}>
              <div className="badge-button-layout">
                <div className="badge-button-header">
                  <span><Download size={14}/> ZIP exportieren</span>
                  {exportUsage && <UsageBadge {...exportUsage} />}
                </div>
                <span className="badge-button-description">je eine CSV pro Kategorie</span>
              </div>
            </button>
            <button className="btn btn-secondary btn-full"
              onClick={()=>api.exportJson()}>
              <div className="badge-button-layout">
                <div className="badge-button-header">
                  <span><Download size={14}/> JSON exportieren</span>
                  {exportUsage && <UsageBadge {...exportUsage} />}
                </div>
                <span className="badge-button-description">maschinenlesbar, alles in einer Datei</span>
              </div>
            </button>
          </>}
        </div>
        <p style={{fontSize:11,color:'var(--text3)',marginTop:8}}>
          Der ZIP-Export enthält separate Dateien für Excel und eine lesbare KI-Auswertungsdatei.
        </p>
      </div>

      {/* Import */}
      <div className="card section-gap">
        <div className="card-title">Backup importieren</div>
        <p style={{fontSize:13,color:'var(--text2)',marginBottom:12,lineHeight:1.6}}>
          Importiere einen ZIP-Export zurück in <strong>{activeProfile?.name}</strong>.
          Vorhandene Einträge werden nicht überschrieben.
        </p>
        <div style={{display:'flex',flexDirection:'column',gap:8}}>
          {!canExport && (
            <div style={{padding:'10px 12px',background:'#FCEBEB',borderRadius:8,
              fontSize:13,color:'#D85A30',marginBottom:8}}>
              🔒 Import ist für dein Profil nicht freigeschaltet. Bitte den Admin kontaktieren.
            </div>
          )}
          {canExport && (
            <>
              <label className="btn btn-primary btn-full"
                style={{cursor:importing?'wait':'pointer',opacity:importing?0.6:1}}>
                <input type="file" accept=".zip" onChange={handleImport}
                  disabled={importing}
                  style={{display:'none'}}/>
                {importing ? (
                  <>Importiere...</>
                ) : (
                  <>
                    <Upload size={14}/> ZIP-Backup importieren
                  </>
                )}
              </label>
              {importMsg && (
                <div style={{
                  padding:'10px 12px',
                  background: importMsg.type === 'success' ? '#E1F5EE' : '#FCEBEB',
                  borderRadius:8,
                  fontSize:12,
                  color: importMsg.type === 'success' ? 'var(--accent)' : '#D85A30',
                  lineHeight:1.4
                }}>
                  {importMsg.text}
                </div>
              )}
            </>
          )}
        </div>
        <p style={{fontSize:11,color:'var(--text3)',marginTop:8}}>
          Der Import erkennt automatisch das Format und importiert nur neue Einträge.
        </p>
      </div>

      {saved && (
        <div style={{position:'fixed',bottom:80,left:'50%',transform:'translateX(-50%)',
          background:'var(--accent)',color:'white',padding:'8px 20px',borderRadius:20,
          fontSize:13,fontWeight:600,display:'flex',alignItems:'center',gap:6,zIndex:100}}>
          <Check size={14}/> Gespeichert
        </div>
      )}
    </div>
  )
}