'use client'

import React, { useState, useEffect } from 'react'
import { useParams, useRouter } from 'next/navigation'
import Link from 'next/link'
import { AssessmentResultCard } from '@/components/sdk/use-case-assessment/AssessmentResultCard'

interface TriggeredRule {
  code: string
  category: string
  title: string
  description: string
  severity: string
  score_delta: number
  gdpr_ref: string
}

interface RequiredControl {
  id: string
  title: string
  description: string
  severity: string
  category: string
  gdpr_ref: string
}

interface PatternRecommendation {
  pattern_id: string
  title: string
  description: string
  rationale: string
  priority: number
}

interface ForbiddenPattern {
  pattern_id: string
  title: string
  description: string
  reason: string
}

interface FullAssessment {
  id: string
  title: string
  tenant_id: string
  domain: string
  created_at: string
  intake?: {
    use_case_text?: string
    [key: string]: unknown
  }
  // Flat result fields
  feasibility: string
  risk_level: string
  risk_score: number
  complexity: string
  dsfa_recommended: boolean
  art22_risk: boolean
  training_allowed: string
  triggered_rules?: TriggeredRule[]
  required_controls?: RequiredControl[]
  recommended_architecture?: PatternRecommendation[]
  forbidden_patterns?: ForbiddenPattern[]
  explanation_text?: string
  explanation_model?: string
  explanation_generated_at?: string
  policy_version: string
}

export default function AssessmentDetailPage() {
  const params = useParams()
  const router = useRouter()
  const assessmentId = params.id as string

  const [assessment, setAssessment] = useState<FullAssessment | null>(null)
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState<string | null>(null)
  const [explaining, setExplaining] = useState(false)
  const [explanationError, setExplanationError] = useState<string | null>(null)

  async function loadAssessment() {
    const response = await fetch(`/api/sdk/v1/ucca/assessments/${assessmentId}`)
    if (!response.ok) throw new Error('Assessment nicht gefunden')
    return response.json()
  }

  useEffect(() => {
    if (!assessmentId) return
    loadAssessment()
      .then(data => setAssessment(data))
      .catch(() => {
        // Fallback: fetch from list
        fetch('/api/sdk/v1/ucca/assessments')
          .then(r => r.json())
          .then(data => {
            const found = (data.assessments || []).find((a: FullAssessment) => a.id === assessmentId)
            if (found) {
              setAssessment(found)
              setError(null)
            } else {
              setError('Assessment nicht gefunden')
            }
          })
          .catch(() => setError('Fehler beim Laden'))
      })
      .finally(() => setLoading(false))
  }, [assessmentId])

  const handleDelete = async () => {
    if (!confirm('Assessment wirklich loeschen?')) return
    try {
      await fetch(`/api/sdk/v1/ucca/assessments/${assessmentId}`, { method: 'DELETE' })
      router.push('/sdk/use-cases')
    } catch {
      // Ignore delete errors
    }
  }

  const handleExplain = async () => {
    setExplaining(true)
    setExplanationError(null)
    try {
      const res = await fetch(`/api/sdk/v1/ucca/assessments/${assessmentId}/explain`, {
        method: 'POST',
        headers: { 'Content-Type': 'application/json' },
        body: JSON.stringify({ language: 'de' }),
      })
      if (!res.ok) throw new Error('Fehler bei der Erklärung')
      // Reload assessment to get updated explanation_text
      const updated = await fetch(`/api/sdk/v1/ucca/assessments/${assessmentId}`)
      setAssessment(await updated.json())
    } catch (err) {
      setExplanationError(err instanceof Error ? err.message : 'Fehler')
    } finally {
      setExplaining(false)
    }
  }

  if (loading) {
    return (
      <div className="flex items-center justify-center h-64">
        <div className="text-gray-500">Lade Assessment...</div>
      </div>
    )
  }

  if (error || !assessment) {
    return (
      <div className="space-y-4">
        <div className="bg-red-50 border border-red-200 rounded-lg p-6 text-center">
          <h3 className="text-lg font-semibold text-red-800">Fehler</h3>
          <p className="text-red-600 mt-1">{error || 'Assessment nicht gefunden'}</p>
        </div>
        <Link href="/sdk/use-cases" className="text-purple-600 hover:text-purple-700">
          Zurueck zur Uebersicht
        </Link>
      </div>
    )
  }

  // Build result object for AssessmentResultCard from flat assessment fields
  const resultForCard = {
    feasibility: assessment.feasibility,
    risk_level: assessment.risk_level,
    risk_score: assessment.risk_score,
    complexity: assessment.complexity,
    dsfa_recommended: assessment.dsfa_recommended,
    art22_risk: assessment.art22_risk,
    training_allowed: assessment.training_allowed,
    // AssessmentResultCard expects rule_code; backend stores code — map here
    triggered_rules: assessment.triggered_rules?.map(r => ({
      rule_code: r.code,
      title: r.title,
      severity: r.severity,
      gdpr_ref: r.gdpr_ref,
    })),
    required_controls: assessment.required_controls?.map(c => ({
      id: c.id,
      title: c.title,
      description: c.description,
      effort: c.category,
    })),
    recommended_architecture: assessment.recommended_architecture?.map(p => ({
      id: p.pattern_id,
      title: p.title,
      description: p.description,
      benefit: p.rationale,
    })),
    summary: '',
    recommendation: '',
  }

  return (
    <div className="space-y-6">
      {/* Breadcrumb */}
      <div className="flex items-center gap-2 text-sm text-gray-500">
        <Link href="/sdk/use-cases" className="hover:text-purple-600">Use Cases</Link>
        <span>/</span>
        <span className="text-gray-900">{assessment.title || assessmentId.slice(0, 8)}</span>
      </div>

      {/* Header */}
      <div className="flex items-start justify-between gap-4">
        <div>
          <h1 className="text-2xl font-bold text-gray-900">{assessment.title || 'Assessment Detail'}</h1>
          <div className="flex items-center gap-4 mt-2 text-sm text-gray-500">
            <span>Domain: {assessment.domain}</span>
            <span>Erstellt: {new Date(assessment.created_at).toLocaleDateString('de-DE')}</span>
          </div>
        </div>
        <div className="flex items-center gap-2 flex-wrap justify-end">
          <button
            onClick={handleExplain}
            disabled={explaining}
            className="px-4 py-2 text-sm bg-purple-100 text-purple-700 rounded-lg hover:bg-purple-200 transition-colors disabled:opacity-50"
          >
            {explaining ? 'Generiere...' : '✨ KI-Erklärung'}
          </button>
          <a
            href={`/api/sdk/v1/ucca/export/${assessmentId}?format=md`}
            download
            className="px-4 py-2 text-sm bg-gray-100 text-gray-700 rounded-lg hover:bg-gray-200 transition-colors"
          >
            ↓ Markdown
          </a>
          <a
            href={`/api/sdk/v1/ucca/export/${assessmentId}?format=json`}
            download
            className="px-4 py-2 text-sm bg-gray-100 text-gray-700 rounded-lg hover:bg-gray-200 transition-colors"
          >
            ↓ JSON
          </a>
          <Link
            href={`/sdk/use-cases/new?edit=${assessmentId}`}
            className="px-4 py-2 text-sm bg-purple-600 text-white rounded-lg hover:bg-purple-700 transition-colors"
          >
            Bearbeiten
          </Link>
          <button
            onClick={handleDelete}
            className="px-4 py-2 text-sm text-red-600 hover:bg-red-50 rounded-lg transition-colors"
          >
            Loeschen
          </button>
          <Link
            href="/sdk/use-cases"
            className="px-4 py-2 text-sm bg-gray-100 text-gray-700 rounded-lg hover:bg-gray-200 transition-colors"
          >
            Zurueck
          </Link>
        </div>
      </div>

      {/* Explanation error */}
      {explanationError && (
        <div className="bg-red-50 border border-red-200 rounded-lg p-4 text-red-700 text-sm">
          {explanationError}
        </div>
      )}

      {/* Use Case Text */}
      {assessment.intake?.use_case_text && (
        <div className="bg-gray-50 rounded-xl border border-gray-200 p-6">
          <h3 className="text-sm font-medium text-gray-500 mb-2">Beschreibung des Anwendungsfalls</h3>
          <p className="text-gray-800 whitespace-pre-wrap">{assessment.intake.use_case_text as string}</p>
        </div>
      )}

      {/* Result */}
      <AssessmentResultCard result={resultForCard as Parameters<typeof AssessmentResultCard>[0]['result']} />

      {/* KI-Erklärung */}
      {assessment.explanation_text && (
        <div className="bg-purple-50 border border-purple-200 rounded-xl p-6">
          <div className="flex items-center gap-2 mb-3">
            <span className="text-lg">✨</span>
            <h3 className="text-sm font-semibold text-purple-800">KI-Erklärung</h3>
            {assessment.explanation_model && (
              <span className="text-xs text-purple-500 ml-auto">via {assessment.explanation_model}</span>
            )}
          </div>
          <p className="text-purple-900 whitespace-pre-wrap text-sm leading-relaxed">
            {assessment.explanation_text}
          </p>
        </div>
      )}
    </div>
  )
}