'use client'

import React, { useState } from 'react'
import Link from 'next/link'
import { useRouter } from 'next/navigation'
import { useSDK, getStepById, getNextStep, getPreviousStep, SDK_STEPS } from '@/lib/sdk'
import { STEP_EXPLANATIONS } from './StepExplanations'

// =============================================================================
// TYPES
// =============================================================================

export interface StepTip {
  icon: 'info' | 'warning' | 'success' | 'lightbulb'
  title: string
  description: string
}

interface StepHeaderProps {
  stepId: string
  title?: string
  description?: string
  explanation?: string
  tips?: StepTip[]
  showNavigation?: boolean
  showProgress?: boolean
  onComplete?: () => void
  isCompleted?: boolean
  children?: React.ReactNode
}

// =============================================================================
// ICONS
// =============================================================================

const icons = {
  info: (
    <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
      <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M13 16h-1v-4h-1m1-4h.01M21 12a9 9 0 11-18 0 9 9 0 0118 0z" />
    </svg>
  ),
  warning: (
    <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
      <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M12 9v2m0 4h.01m-6.938 4h13.856c1.54 0 2.502-1.667 1.732-3L13.732 4c-.77-1.333-2.694-1.333-3.464 0L3.34 16c-.77 1.333.192 3 1.732 3z" />
    </svg>
  ),
  success: (
    <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
      <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M9 12l2 2 4-4m6 2a9 9 0 11-18 0 9 9 0 0118 0z" />
    </svg>
  ),
  lightbulb: (
    <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
      <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M9.663 17h4.673M12 3v1m6.364 1.636l-.707.707M21 12h-1M4 12H3m3.343-5.657l-.707-.707m2.828 9.9a5 5 0 117.072 0l-.548.547A3.374 3.374 0 0014 18.469V19a2 2 0 11-4 0v-.531c0-.895-.356-1.754-.988-2.386l-.548-.547z" />
    </svg>
  ),
  arrowLeft: (
    <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
      <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M10 19l-7-7m0 0l7-7m-7 7h18" />
    </svg>
  ),
  arrowRight: (
    <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
      <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M14 5l7 7m0 0l-7 7m7-7H3" />
    </svg>
  ),
  check: (
    <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
      <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M5 13l4 4L19 7" />
    </svg>
  ),
  help: (
    <svg className="w-5 h-5" fill="none" stroke="currentColor" viewBox="0 0 24 24">
      <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M8.228 9c.549-1.165 2.03-2 3.772-2 2.21 0 4 1.343 4 3 0 1.4-1.278 2.575-3.006 2.907-.542.104-.994.54-.994 1.093m0 3h.01M21 12a9 9 0 11-18 0 9 9 0 0118 0z" />
    </svg>
  ),
}

const tipColors = {
  info: 'bg-blue-50 border-blue-200 text-blue-800',
  warning: 'bg-amber-50 border-amber-200 text-amber-800',
  success: 'bg-green-50 border-green-200 text-green-800',
  lightbulb: 'bg-purple-50 border-purple-200 text-purple-800',
}

const tipIconColors = {
  info: 'text-blue-500',
  warning: 'text-amber-500',
  success: 'text-green-500',
  lightbulb: 'text-purple-500',
}

// =============================================================================
// STEP HEADER COMPONENT
// =============================================================================

export function StepHeader({
  stepId,
  title: titleProp,
  description: descriptionProp,
  explanation: explanationProp,
  tips: tipsProp,
  showNavigation = true,
  showProgress = true,
  onComplete,
  isCompleted = false,
  children,
}: StepHeaderProps) {
  const router = useRouter()
  const { state, dispatch } = useSDK()
  const [showHelp, setShowHelp] = useState(false)

  // Look up defaults from STEP_EXPLANATIONS when props are not provided
  const preset = STEP_EXPLANATIONS[stepId as keyof typeof STEP_EXPLANATIONS]
  const title = titleProp ?? preset?.title ?? stepId
  const description = descriptionProp ?? preset?.description ?? ''
  const explanation = explanationProp ?? preset?.explanation ?? ''
  const tips = tipsProp ?? preset?.tips ?? []

  const currentStep = getStepById(stepId)
  const prevStep = getPreviousStep(stepId)
  const nextStep = getNextStep(stepId)

  const stepCompleted = state.completedSteps.includes(stepId)

  const handleComplete = () => {
    if (onComplete) {
      onComplete()
    }
    dispatch({ type: 'COMPLETE_STEP', payload: stepId })
    if (nextStep) {
      router.push(nextStep.url)
    }
  }

  const handleSkip = () => {
    if (nextStep) {
      router.push(nextStep.url)
    }
  }

  // Calculate step progress within phase
  const phaseSteps = currentStep ?
    SDK_STEPS.filter(s => s.phase === currentStep.phase).length : 0
  const stepNumber = currentStep?.order || 0

  return (
    <div className="space-y-6">
      {/* Breadcrumb & Progress */}
      {showProgress && currentStep && (
        <div className="flex items-center justify-between">
          <div className="flex items-center gap-2 text-sm text-gray-500">
            <Link href="/sdk" className="hover:text-purple-600 transition-colors">
              SDK
            </Link>
            <span>/</span>
            <span className="text-gray-700">
              Phase {currentStep.phase}: {currentStep.phase === 1 ? 'Assessment' : 'Dokumente'}
            </span>
            <span>/</span>
            <span className="text-purple-600 font-medium">{currentStep.nameShort}</span>
          </div>
          <div className="flex items-center gap-2 text-sm">
            <span className="text-gray-500">Schritt {stepNumber} von {phaseSteps}</span>
            <div className="w-24 h-2 bg-gray-200 rounded-full overflow-hidden">
              <div
                className="h-full bg-purple-600 rounded-full transition-all"
                style={{ width: `${(stepNumber / phaseSteps) * 100}%` }}
              />
            </div>
          </div>
        </div>
      )}

      {/* Main Header Card */}
      <div className="bg-white rounded-xl border border-gray-200 overflow-hidden">
        {/* Header */}
        <div className="p-6 border-b border-gray-100">
          <div className="flex items-start justify-between">
            <div className="flex-1">
              <div className="flex items-center gap-3">
                <h1 className="text-2xl font-bold text-gray-900">{title}</h1>
                {stepCompleted && (
                  <span className="flex items-center gap-1 px-2 py-1 text-xs bg-green-100 text-green-700 rounded-full">
                    {icons.check}
                    Abgeschlossen
                  </span>
                )}
              </div>
              <p className="mt-2 text-gray-500">{description}</p>
            </div>
            <button
              onClick={() => setShowHelp(!showHelp)}
              className={`p-2 rounded-lg transition-colors ${
                showHelp ? 'bg-purple-100 text-purple-600' : 'text-gray-400 hover:bg-gray-100 hover:text-gray-600'
              }`}
              title="Hilfe anzeigen"
            >
              {icons.help}
            </button>
          </div>
        </div>

        {/* Explanation Panel (collapsible) */}
        {showHelp && (
          <div className="px-6 py-4 bg-gradient-to-r from-purple-50 to-indigo-50 border-b border-purple-100">
            <div className="flex items-start gap-3">
              <div className="p-2 bg-purple-100 rounded-lg text-purple-600">
                {icons.lightbulb}
              </div>
              <div>
                <h3 className="font-medium text-purple-900">Was ist das?</h3>
                <p className="mt-1 text-sm text-purple-800">{explanation}</p>
              </div>
            </div>
          </div>
        )}

        {/* Tips */}
        {tips.length > 0 && (
          <div className="px-6 py-4 space-y-3 bg-gray-50 border-b border-gray-100">
            {tips.map((tip, index) => (
              <div
                key={index}
                className={`flex items-start gap-3 p-3 rounded-lg border ${tipColors[tip.icon]}`}
              >
                <div className={tipIconColors[tip.icon]}>
                  {icons[tip.icon]}
                </div>
                <div>
                  <h4 className="font-medium text-sm">{tip.title}</h4>
                  <p className="text-sm opacity-80">{tip.description}</p>
                </div>
              </div>
            ))}
          </div>
        )}

        {/* Action Buttons */}
        {children && (
          <div className="px-6 py-4 bg-gray-50">
            {children}
          </div>
        )}
      </div>

      {/* Navigation */}
      {showNavigation && (
        <div className="flex items-center justify-between">
          <div>
            {prevStep ? (
              <Link
                href={prevStep.url}
                className="flex items-center gap-2 px-4 py-2 text-gray-600 hover:text-gray-900 hover:bg-gray-100 rounded-lg transition-colors"
              >
                {icons.arrowLeft}
                <span>Zurueck: {prevStep.nameShort}</span>
              </Link>
            ) : (
              <Link
                href="/sdk"
                className="flex items-center gap-2 px-4 py-2 text-gray-600 hover:text-gray-900 hover:bg-gray-100 rounded-lg transition-colors"
              >
                {icons.arrowLeft}
                <span>Zur Uebersicht</span>
              </Link>
            )}
          </div>

          <div className="flex items-center gap-3">
            {nextStep && !stepCompleted && (
              <button
                onClick={handleSkip}
                className="px-4 py-2 text-gray-500 hover:text-gray-700 hover:bg-gray-100 rounded-lg transition-colors"
              >
                Ueberspringen
              </button>
            )}
            {nextStep ? (
              <button
                onClick={handleComplete}
                className="flex items-center gap-2 px-6 py-2 bg-purple-600 text-white rounded-lg hover:bg-purple-700 transition-colors"
              >
                <span>{stepCompleted ? 'Weiter' : 'Abschliessen & Weiter'}</span>
                {icons.arrowRight}
              </button>
            ) : (
              <button
                onClick={handleComplete}
                className="flex items-center gap-2 px-6 py-2 bg-green-600 text-white rounded-lg hover:bg-green-700 transition-colors"
              >
                {icons.check}
                <span>Phase abschliessen</span>
              </button>
            )}
          </div>
        </div>
      )}
    </div>
  )
}

export default StepHeader