'use client'

import { useState, useEffect, useRef, useCallback } from 'react'
import { Button } from '@/components/ui/button'
import { Input } from '@/components/ui/input'
import { useToast } from '@/components/ui/use-toast'
import {
  GraduationCap,
  Plus,
  Target,
  Check,
  CircleDashed,
  CircleSlash,
  MinusCircle,
  Trash2,
  ClipboardCheck,
  Loader2,
} from 'lucide-react'

type GoalStatus = 'OPEN' | 'REACHED' | 'PARTIAL' | 'MISSED'

interface ExerciseGoal {
  id: string
  text: string
  status: GoalStatus
  note: string | null
  sortOrder: number
}

interface ExerciseCockpitProps {
  projectId: string | null
  projectTitle: string
  canEdit: boolean
  initialEvaluation?: string
  onEvaluationSaved?: (value: string) => void
}

const STATUS_CONFIG: Record<GoalStatus, { label: string; icon: typeof Check; cls: string; activeCls: string }> = {
  OPEN: {
    label: 'Offen',
    icon: CircleDashed,
    cls: 'text-muted-foreground',
    activeCls: 'bg-muted text-foreground border-muted-foreground/40',
  },
  REACHED: {
    label: 'Erreicht',
    icon: Check,
    cls: 'text-green-600',
    activeCls: 'bg-green-100 text-green-700 border-green-500 dark:bg-green-950/40 dark:text-green-300',
  },
  PARTIAL: {
    label: 'Teilweise',
    icon: MinusCircle,
    cls: 'text-amber-600',
    activeCls: 'bg-amber-100 text-amber-700 border-amber-500 dark:bg-amber-950/40 dark:text-amber-300',
  },
  MISSED: {
    label: 'Nicht erreicht',
    icon: CircleSlash,
    cls: 'text-red-600',
    activeCls: 'bg-red-100 text-red-700 border-red-500 dark:bg-red-950/40 dark:text-red-300',
  },
}

const STATUS_ORDER: GoalStatus[] = ['OPEN', 'REACHED', 'PARTIAL', 'MISSED']

export function ExerciseCockpit({ projectId, projectTitle, canEdit, initialEvaluation, onEvaluationSaved }: ExerciseCockpitProps) {
  const [goals, setGoals] = useState<ExerciseGoal[]>([])
  const [isLoading, setIsLoading] = useState(false)
  const [newGoalText, setNewGoalText] = useState('')
  const [isAdding, setIsAdding] = useState(false)
  const [evaluation, setEvaluation] = useState(initialEvaluation || '')
  const [evalSaving, setEvalSaving] = useState(false)
  const evalDebounce = useRef<NodeJS.Timeout | null>(null)
  const { toast } = useToast()

  // Ziele laden
  const loadGoals = useCallback(async () => {
    if (!projectId) {
      setGoals([])
      return
    }
    setIsLoading(true)
    try {
      const res = await fetch(`/api/projects/${projectId}/exercise-goals`)
      if (res.ok) {
        const data = await res.json()
        setGoals(data.goals || [])
      }
    } catch (e) {
      console.warn('Fehler beim Laden der Übungsziele:', e)
    } finally {
      setIsLoading(false)
    }
  }, [projectId])

  useEffect(() => {
    loadGoals()
  }, [loadGoals])

  // Auswertung übernehmen, wenn sich das Projekt ändert
  useEffect(() => {
    setEvaluation(initialEvaluation || '')
  }, [projectId, initialEvaluation])

  const addGoal = async () => {
    if (!projectId || !newGoalText.trim()) return
    setIsAdding(true)
    try {
      const res = await fetch(`/api/projects/${projectId}/exercise-goals`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ text: newGoalText.trim() }),
      })
      if (!res.ok) throw new Error('Ziel konnte nicht angelegt werden')
      const data = await res.json()
      setGoals((prev) => [...prev, data.goal])
      setNewGoalText('')
    } catch (e) {
      toast({ title: 'Fehler', description: e instanceof Error ? e.message : 'Unbekannter Fehler', variant: 'destructive' })
    } finally {
      setIsAdding(false)
    }
  }

  const patchGoal = async (goalId: string, patch: Partial<Pick<ExerciseGoal, 'text' | 'status' | 'note'>>) => {
    if (!projectId) return
    // Optimistisch aktualisieren
    setGoals((prev) => prev.map((g) => (g.id === goalId ? { ...g, ...patch } : g)))
    try {
      await fetch(`/api/projects/${projectId}/exercise-goals/${goalId}`, {
        method: 'PUT',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify(patch),
      })
    } catch (e) {
      console.warn('Fehler beim Speichern des Ziels:', e)
      loadGoals()
    }
  }

  const deleteGoal = async (goalId: string) => {
    if (!projectId) return
    setGoals((prev) => prev.filter((g) => g.id !== goalId))
    try {
      await fetch(`/api/projects/${projectId}/exercise-goals/${goalId}`, { method: 'DELETE' })
    } catch (e) {
      console.warn('Fehler beim Löschen des Ziels:', e)
      loadGoals()
    }
  }

  // Auswertung mit Debounce speichern
  const handleEvaluationChange = (value: string) => {
    setEvaluation(value)
    if (!projectId) return
    if (evalDebounce.current) clearTimeout(evalDebounce.current)
    evalDebounce.current = setTimeout(async () => {
      setEvalSaving(true)
      try {
        await fetch(`/api/projects/${projectId}`, {
          method: 'PATCH',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify({ exerciseEvaluation: value }),
        })
        onEvaluationSaved?.(value)
      } catch (e) {
        console.warn('Fehler beim Speichern der Auswertung:', e)
      } finally {
        setEvalSaving(false)
      }
    }, 800)
  }

  const reachedCount = goals.filter((g) => g.status === 'REACHED').length
  const total = goals.length

  return (
    <div className="h-full overflow-auto bg-blue-50/40 dark:bg-background">
      {/* Header */}
      <div className="p-3 md:p-4 border-b-2 border-blue-600 dark:border-blue-800 bg-white dark:bg-card shadow-sm">
        <div className="flex items-center justify-between mb-1">
          <h2 className="text-lg md:text-xl font-bold flex items-center gap-2 text-blue-800 dark:text-blue-400">
            <GraduationCap className="w-5 h-5 md:w-6 md:h-6" />
            Übungs-Cockpit
          </h2>
          {total > 0 && (
            <span className="text-sm font-medium text-blue-700 dark:text-blue-300 bg-blue-100 dark:bg-blue-950/40 px-2 py-0.5 rounded">
              {reachedCount}/{total} erreicht
            </span>
          )}
        </div>
        <p className="text-xs text-muted-foreground truncate">{projectTitle || 'Übung'}</p>
      </div>

      <div className="p-3 md:p-4 space-y-6 max-w-3xl">
        {/* Übungsziele */}
        <section>
          <h3 className="text-sm font-semibold flex items-center gap-2 mb-3 text-foreground/80">
            <Target className="w-4 h-4 text-blue-600" />
            Übungsziele
          </h3>

          {canEdit && (
            <div className="flex gap-2 mb-3">
              <Input
                value={newGoalText}
                onChange={(e) => setNewGoalText(e.target.value)}
                onKeyDown={(e) => { if (e.key === 'Enter') addGoal() }}
                placeholder="Neues Übungsziel — z.B. Wasserbezug ab Hydrant befehlen"
                disabled={isAdding || !projectId}
              />
              <Button onClick={addGoal} disabled={isAdding || !newGoalText.trim() || !projectId}>
                {isAdding ? <Loader2 className="w-4 h-4 animate-spin" /> : <Plus className="w-4 h-4" />}
              </Button>
            </div>
          )}

          {isLoading ? (
            <div className="flex items-center justify-center py-8 text-muted-foreground">
              <Loader2 className="w-5 h-5 animate-spin mr-2" /> Lädt…
            </div>
          ) : goals.length === 0 ? (
            <p className="text-sm text-muted-foreground py-6 text-center border border-dashed rounded-lg">
              Noch keine Ziele. Lege in der Vorbereitung fest, was die Übung auslösen soll.
            </p>
          ) : (
            <ul className="space-y-2">
              {goals.map((goal) => (
                <li key={goal.id} className="border rounded-lg p-3 bg-white dark:bg-card">
                  <div className="flex items-start justify-between gap-2">
                    <p className="text-sm font-medium flex-1">{goal.text}</p>
                    {canEdit && (
                      <button
                        onClick={() => deleteGoal(goal.id)}
                        className="text-muted-foreground hover:text-destructive shrink-0"
                        title="Ziel löschen"
                      >
                        <Trash2 className="w-4 h-4" />
                      </button>
                    )}
                  </div>

                  {/* Zielerreichung */}
                  <div className="flex flex-wrap gap-1.5 mt-2">
                    {STATUS_ORDER.map((s) => {
                      const cfg = STATUS_CONFIG[s]
                      const Icon = cfg.icon
                      const active = goal.status === s
                      return (
                        <button
                          key={s}
                          type="button"
                          onClick={() => canEdit && patchGoal(goal.id, { status: s })}
                          disabled={!canEdit}
                          className={`inline-flex items-center gap-1 rounded-md border px-2 py-1 text-xs font-medium transition-colors disabled:cursor-default ${
                            active ? cfg.activeCls : 'border-transparent text-muted-foreground hover:bg-accent'
                          }`}
                        >
                          <Icon className="w-3.5 h-3.5" /> {cfg.label}
                        </button>
                      )
                    })}
                  </div>

                  {/* Notiz zum Ziel */}
                  {canEdit && (
                    <Input
                      value={goal.note || ''}
                      onChange={(e) => setGoals((prev) => prev.map((g) => (g.id === goal.id ? { ...g, note: e.target.value } : g)))}
                      onBlur={(e) => patchGoal(goal.id, { note: e.target.value })}
                      placeholder="Notiz / Beobachtung (optional)"
                      className="mt-2 h-8 text-xs"
                    />
                  )}
                  {!canEdit && goal.note && (
                    <p className="mt-2 text-xs text-muted-foreground">{goal.note}</p>
                  )}
                </li>
              ))}
            </ul>
          )}
        </section>

        {/* Auswertung */}
        <section>
          <h3 className="text-sm font-semibold flex items-center gap-2 mb-3 text-foreground/80">
            <ClipboardCheck className="w-4 h-4 text-blue-600" />
            Auswertung
            {evalSaving && <Loader2 className="w-3.5 h-3.5 animate-spin text-muted-foreground" />}
          </h3>
          <textarea
            value={evaluation}
            onChange={(e) => handleEvaluationChange(e.target.value)}
            disabled={!canEdit || !projectId}
            rows={6}
            placeholder="Gesamtbeurteilung, Lessons Learned, was ist aufgefallen…"
            className="w-full rounded-md border border-input bg-background px-3 py-2 text-sm focus:outline-none focus:ring-2 focus:ring-blue-500 disabled:opacity-60 resize-y"
          />
          <p className="text-xs text-muted-foreground mt-1">Wird automatisch gespeichert.</p>
        </section>
      </div>
    </div>
  )
}
