/**
 * UploadWizard – refactored orchestrator
 *
 * A 3-step upload wizard that delegates:
 *   - Machine state    → useUploadMachine
 *   - File validation  → useFileValidation
 *   - Vision AI tags   → useVisionTags
 *   - Step rendering   → Step1FileUpload / Step2Details / Step3Publish
 *   - Reusable UI      → ContentTypeSelector / CategorySelector / UploadSidebar …
 */
import React, { useCallback, useEffect, useMemo, useRef, useState } from 'react'
import { AnimatePresence, motion, useReducedMotion } from 'framer-motion'

import useUploadMachine, { machineStates } from '../../hooks/upload/useUploadMachine'
import useFileValidation from '../../hooks/upload/useFileValidation'
import useVisionTags from '../../hooks/upload/useVisionTags'

import UploadStepper from './UploadStepper'
import UploadActions from './UploadActions'
import Step1FileUpload from './steps/Step1FileUpload'
import Step2Details from './steps/Step2Details'
import Step3Publish from './steps/Step3Publish'

import {
  buildCategoryTree,
  getContentTypeValue,
} from '../../lib/uploadUtils'

// ─── Wizard step config ───────────────────────────────────────────────────────
const wizardSteps = [
  { key: 'upload', label: 'Upload' },
  { key: 'details', label: 'Details' },
  { key: 'publish', label: 'Publish' },
]

// ─── Helpers ─────────────────────────────────────────────────────────────────
function isValidForUpload(primaryFile, primaryErrors, isArchive, screenshotErrors) {
  if (!primaryFile) return false
  if (primaryErrors.length > 0) return false
  if (isArchive && screenshotErrors.length > 0) return false
  return true
}

const initialMetadata = {
  title: '',
  rootCategoryId: '',
  subCategoryId: '',
  tags: [],
  description: '',
  rightsAccepted: false,
  contentType: '',
}

// ─── Component ────────────────────────────────────────────────────────────────
export default function UploadWizard({
  onValidationStateChange,
  initialDraftId = null,
  chunkSize,
  contentTypes = [],
  suggestedTags = [],
}) {
  // ── UI state ──────────────────────────────────────────────────────────────
  const [activeStep, setActiveStep] = useState(1)
  const [showRestoredBanner, setShowRestoredBanner] = useState(Boolean(initialDraftId))
  const [isUploadLocked, setIsUploadLocked] = useState(false)
  const [resolvedArtworkId, setResolvedArtworkId] = useState(() => {
    const parsed = Number(initialDraftId)
    return Number.isFinite(parsed) && parsed > 0 ? Math.floor(parsed) : null
  })

  // ── File + screenshot state ───────────────────────────────────────────────
  const [primaryFile, setPrimaryFile] = useState(null)
  const [screenshots, setScreenshots] = useState([])

  // ── Metadata state ────────────────────────────────────────────────────────
  const [metadata, setMetadata] = useState(initialMetadata)

  // ── Refs ──────────────────────────────────────────────────────────────────
  const prefersReducedMotion = useReducedMotion()
  const stepContentRef = useRef(null)
  const stepHeadingRef = useRef(null)
  const hasAutoAdvancedRef = useRef(false)

  const quickTransition = prefersReducedMotion ? { duration: 0 } : { duration: 0.2, ease: 'easeOut' }

  // ── File validation hook ──────────────────────────────────────────────────
  const {
    primaryType,
    primaryErrors,
    primaryWarnings,
    fileMetadata,
    primaryPreviewUrl,
    screenshotErrors,
    screenshotPerFileErrors,
  } = useFileValidation(primaryFile, screenshots)

  const isArchive = primaryType === 'archive'

  const canStartUpload = isValidForUpload(primaryFile, primaryErrors, isArchive, screenshotErrors)

  // ── Machine hook ──────────────────────────────────────────────────────────
  const {
    machine,
    runUploadFlow,
    handleCancel,
    handlePublish,
    handleRetry,
    resetMachine,
    abortAllRequests,
    clearPolling,
  } = useUploadMachine({
    primaryFile,
    canStartUpload,
    primaryType,
    isArchive,
    initialDraftId,
    metadata,
    chunkSize,
    onArtworkCreated: (id) => setResolvedArtworkId(id),
  })

  // ── Upload-ready flag (needed before vision hook) ─────────────────────────
  const uploadReady = (
    machine.state === machineStates.ready_to_publish ||
    machine.processingStatus === 'ready' ||
    machine.state === machineStates.complete
  )

  // ── Vision tags hook – fires on upload completion, not step change ──────────
  // Starts fetching AI tag suggestions while the user is still on Step 1,
  // so results are ready (or partially ready) by the time Step 2 opens.
  const { visionSuggestedTags } = useVisionTags(resolvedArtworkId, uploadReady)

  // ── Category tree computation ─────────────────────────────────────────────
  const categoryTreeByType = useMemo(() => {
    const result = {}
    const list = Array.isArray(contentTypes) ? contentTypes : []
    list.forEach((type) => {
      const value = getContentTypeValue(type)
      if (!value) return
      result[value] = buildCategoryTree([type])
    })
    return result
  }, [contentTypes])

  const filteredCategoryTree = useMemo(() => {
    const selected = String(metadata.contentType || '')
    if (!selected) return []
    return categoryTreeByType[selected] || []
  }, [categoryTreeByType, metadata.contentType])

  const allRootCategoryOptions = useMemo(() => {
    const items = []
    Object.entries(categoryTreeByType).forEach(([contentTypeValue, roots]) => {
      roots.forEach((root) => items.push({ ...root, contentTypeValue }))
    })
    return items
  }, [categoryTreeByType])

  const selectedRootCategory = useMemo(() => {
    const id = String(metadata.rootCategoryId || '')
    if (!id) return null
    return (
      filteredCategoryTree.find((r) => String(r.id) === id) ||
      allRootCategoryOptions.find((r) => String(r.id) === id) ||
      null
    )
  }, [filteredCategoryTree, allRootCategoryOptions, metadata.rootCategoryId])

  const requiresSubCategory = Boolean(
    selectedRootCategory &&
    Array.isArray(selectedRootCategory.children) &&
    selectedRootCategory.children.length > 0
  )

  // ── Metadata validation ───────────────────────────────────────────────────
  const metadataErrors = useMemo(() => {
    const errors = {}
    if (!String(metadata.title || '').trim()) errors.title = 'Title is required.'
    if (!metadata.contentType) errors.contentType = 'Content type is required.'
    if (!metadata.rootCategoryId) errors.category = 'Root category is required.'
    if (metadata.rootCategoryId && requiresSubCategory && !metadata.subCategoryId) {
      errors.category = 'Subcategory is required for the selected category.'
    }
    if (!metadata.rightsAccepted) errors.rights = 'Rights confirmation is required.'
    return errors
  }, [metadata, requiresSubCategory])

  const detailsValid = Object.keys(metadataErrors).length === 0

  // ── Merged AI + manual suggested tags ────────────────────────────────────
  const mergedSuggestedTags = useMemo(() => {
    const map = new Map()
    const addTag = (item) => {
      if (!item) return
      const key = String(item?.slug || item?.tag || item?.name || item).trim().toLowerCase()
      if (!key || map.has(key)) return
      map.set(key, typeof item === 'string' ? item : {
        id: item.id ?? key,
        name: item.name || item.tag || item.slug || key,
        slug: item.slug || item.tag || key,
        usage_count: Number(item.usage_count || 0),
        is_ai: Boolean(item.is_ai || item.source === 'ai'),
        source: item.source || (item.is_ai ? 'ai' : 'manual'),
      })
    }
    ;(Array.isArray(suggestedTags) ? suggestedTags : []).forEach(addTag)
    ;(Array.isArray(visionSuggestedTags) ? visionSuggestedTags : []).forEach(addTag)
    return Array.from(map.values())
  }, [suggestedTags, visionSuggestedTags])

  // ── Derived flags ─────────────────────────────────────────────────────────
  const highestUnlockedStep = uploadReady ? (detailsValid ? 3 : 2) : 1
  const showProgress = ![machineStates.idle, machineStates.cancelled].includes(machine.state)

  const canPublish = useMemo(() => (
    uploadReady &&
    metadata.rightsAccepted &&
    machine.state !== machineStates.publishing
  ), [uploadReady, metadata.rightsAccepted, machine.state])

  const stepProgressPercent = useMemo(() => {
    if (activeStep === 1) return 33
    if (activeStep === 2) return 66
    return 100
  }, [activeStep])

  // ── Validation surface for parent ────────────────────────────────────────
  const validationErrors = useMemo(
    () => [...primaryErrors, ...screenshotErrors],
    [primaryErrors, screenshotErrors]
  )

  useEffect(() => {
    if (typeof onValidationStateChange === 'function') {
      onValidationStateChange({ isValid: canStartUpload, validationErrors, isArchive })
    }
  }, [canStartUpload, validationErrors, isArchive, onValidationStateChange])

  // ── Auto-advance to step 2 after upload complete ──────────────────────────
  useEffect(() => {
    if (uploadReady && activeStep === 1 && !hasAutoAdvancedRef.current) {
      hasAutoAdvancedRef.current = true
      setIsUploadLocked(true)
      setActiveStep(2)
    }
  }, [uploadReady, activeStep])

  useEffect(() => {
    if (uploadReady) setIsUploadLocked(true)
  }, [uploadReady])

  // ── Step scroll + focus ───────────────────────────────────────────────────
  useEffect(() => {
    if (!stepContentRef.current) return
    stepContentRef.current.scrollIntoView({
      behavior: prefersReducedMotion ? 'auto' : 'smooth',
      block: 'start',
    })
    window.setTimeout(() => {
      stepHeadingRef.current?.focus?.({ preventScroll: true })
    }, 0)
  }, [activeStep, prefersReducedMotion])

  // ── Cleanup ───────────────────────────────────────────────────────────────
  useEffect(() => {
    return () => {
      abortAllRequests()
      clearPolling()
    }
  }, [abortAllRequests, clearPolling])

  // ── Metadata helpers ──────────────────────────────────────────────────────
  const setMeta = useCallback((patch) => setMetadata((prev) => ({ ...prev, ...patch })), [])

  // ── Full reset ────────────────────────────────────────────────────────────
  const handleReset = useCallback(() => {
    resetMachine()
    setPrimaryFile(null)
    setScreenshots([])
    setMetadata(initialMetadata)
    setIsUploadLocked(false)
    hasAutoAdvancedRef.current = false
    setResolvedArtworkId(() => {
      const parsed = Number(initialDraftId)
      return Number.isFinite(parsed) && parsed > 0 ? Math.floor(parsed) : null
    })
    setActiveStep(1)
  }, [resetMachine, initialDraftId])

  const goToStep = useCallback((step) => {
    if (step >= 1 && step <= highestUnlockedStep) setActiveStep(step)
  }, [highestUnlockedStep])

  // ── Step content renderer ─────────────────────────────────────────────────
  const renderStepContent = () => {
    // Complete / success screen
    if (machine.state === machineStates.complete) {
      return (
        <motion.div
          initial={prefersReducedMotion ? false : { opacity: 0, scale: 0.98 }}
          animate={{ opacity: 1, scale: 1 }}
          transition={prefersReducedMotion ? { duration: 0 } : { duration: 0.28, ease: 'easeOut' }}
          className="rounded-2xl ring-1 ring-emerald-300/25 bg-emerald-500/8 p-8 text-center"
        >
          <motion.div
            initial={prefersReducedMotion ? false : { scale: 0.7, opacity: 0 }}
            animate={{ scale: 1, opacity: 1 }}
            transition={prefersReducedMotion ? { duration: 0 } : { delay: 0.1, duration: 0.26, ease: 'backOut' }}
            className="mx-auto mb-4 flex h-14 w-14 items-center justify-center rounded-full ring-2 ring-emerald-300/40 bg-emerald-500/20 text-emerald-200"
          >
            <svg className="h-7 w-7" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" aria-hidden="true">
              <path strokeLinecap="round" strokeLinejoin="round" d="M5 13l4 4L19 7" />
            </svg>
          </motion.div>

          <h3 className="text-xl font-semibold text-white">Your artwork is live 🎉</h3>
          <p className="mt-2 text-sm text-emerald-100/75">
            It has been published and is now visible to the community.
          </p>

          <div className="mt-6 flex flex-wrap justify-center gap-3">
            <a
              href={resolvedArtworkId ? `/artwork/${resolvedArtworkId}` : '/'}
              className="rounded-lg ring-1 ring-emerald-300/45 bg-emerald-400/20 px-4 py-2 text-sm font-medium text-emerald-50 hover:bg-emerald-400/30 transition"
            >
              View artwork
            </a>
            <button
              type="button"
              onClick={handleReset}
              className="rounded-lg ring-1 ring-white/20 bg-white/8 px-4 py-2 text-sm text-white hover:bg-white/15 transition"
            >
              Upload another
            </button>
          </div>
        </motion.div>
      )
    }

    if (activeStep === 1) {
      return (
        <Step1FileUpload
          headingRef={stepHeadingRef}
          primaryFile={primaryFile}
          primaryPreviewUrl={primaryPreviewUrl}
          primaryErrors={primaryErrors}
          primaryWarnings={primaryWarnings}
          fileMetadata={fileMetadata}
          fileSelectionLocked={isUploadLocked}
          onPrimaryFileChange={setPrimaryFile}
          isArchive={isArchive}
          screenshots={screenshots}
          screenshotErrors={screenshotErrors}
          screenshotPerFileErrors={screenshotPerFileErrors}
          onScreenshotsChange={setScreenshots}
          machine={machine}
          showProgress={showProgress}
          onRetry={() => handleRetry(canPublish)}
          onReset={handleReset}
        />
      )
    }

    if (activeStep === 2) {
      return (
        <Step2Details
          headingRef={stepHeadingRef}
          primaryFile={primaryFile}
          primaryPreviewUrl={primaryPreviewUrl}
          isArchive={isArchive}
          fileMetadata={fileMetadata}
          screenshots={screenshots}
          contentTypes={contentTypes}
          metadata={metadata}
          metadataErrors={metadataErrors}
          filteredCategoryTree={filteredCategoryTree}
          allRootCategoryOptions={allRootCategoryOptions}
          requiresSubCategory={requiresSubCategory}
          onContentTypeChange={(value) => setMeta({ contentType: value, rootCategoryId: '', subCategoryId: '' })}
          onRootCategoryChange={(rootId) => setMeta({ rootCategoryId: rootId, subCategoryId: '' })}
          onSubCategoryChange={(subId) => setMeta({ subCategoryId: subId })}
          suggestedTags={mergedSuggestedTags}
          onChangeTitle={(value) => setMeta({ title: value })}
          onChangeTags={(value) => setMeta({ tags: value })}
          onChangeDescription={(value) => setMeta({ description: value })}
          onToggleRights={(value) => setMeta({ rightsAccepted: Boolean(value) })}
        />
      )
    }

    return (
      <Step3Publish
        headingRef={stepHeadingRef}
        primaryFile={primaryFile}
        primaryPreviewUrl={primaryPreviewUrl}
        isArchive={isArchive}
        screenshots={screenshots}
        fileMetadata={fileMetadata}
        metadata={metadata}
        canPublish={canPublish}
        uploadReady={uploadReady}
      />
    )
  }

  // ── Action bar helpers ────────────────────────────────────────────────────
  const disableReason = (() => {
    if (activeStep === 1) return validationErrors[0] || machine.error || 'Complete upload requirements first.'
    if (activeStep === 2) return metadataErrors.title || metadataErrors.contentType || metadataErrors.category || metadataErrors.rights || 'Complete required metadata.'
    return machine.error || 'Publish is available when upload is ready and rights are confirmed.'
  })()

  // ─────────────────────────────────────────────────────────────────────────
  return (
    <section
      ref={stepContentRef}
      className="space-y-6 pb-24 text-white lg:pb-0"
      data-is-archive={isArchive ? 'true' : 'false'}
    >
      {/* Restored draft banner */}
      {showRestoredBanner && (
        <div className="rounded-xl ring-1 ring-sky-300/25 bg-sky-500/10 px-4 py-2.5 text-sm text-sky-100">
          <div className="flex items-center justify-between gap-3">
            <span>Draft restored. Continue from your previous upload session.</span>
            <button
              type="button"
              onClick={() => setShowRestoredBanner(false)}
              className="shrink-0 rounded-md ring-1 ring-sky-200/35 bg-sky-500/15 px-2 py-1 text-xs text-sky-100 hover:bg-sky-500/25 focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-sky-300/70"
            >
              Dismiss
            </button>
          </div>
        </div>
      )}

      {/* Step indicator */}
      <UploadStepper
        steps={wizardSteps}
        activeStep={activeStep}
        highestUnlockedStep={highestUnlockedStep}
        onStepClick={goToStep}
      />

      {/* Thin progress bar */}
      <div className="-mt-3 rounded-full bg-white/8 p-0.5">
        <motion.div
          className="h-1.5 rounded-full bg-gradient-to-r from-sky-400/90 via-cyan-300/90 to-emerald-300/90"
          animate={{ width: `${stepProgressPercent}%` }}
          transition={quickTransition}
        />
      </div>

      {/* Animated step content */}
      <AnimatePresence mode="wait" initial={false}>
        <motion.div
          key={`step-${activeStep}`}
          initial={prefersReducedMotion ? false : { opacity: 0, y: 8 }}
          animate={{ opacity: 1, y: 0 }}
          exit={prefersReducedMotion ? {} : { opacity: 0, y: -8 }}
          transition={quickTransition}
        >
          <div className="max-w-4xl mx-auto">
            {renderStepContent()}
          </div>
        </motion.div>
      </AnimatePresence>

      {/* Sticky action bar */}
      <UploadActions
        step={activeStep}
        canStart={canStartUpload && [machineStates.idle, machineStates.error, machineStates.cancelled].includes(machine.state)}
        canContinue={detailsValid}
        canPublish={canPublish}
        canGoBack={activeStep > 1 && machine.state !== machineStates.complete}
        canReset={Boolean(primaryFile || screenshots.length || metadata.title || metadata.description || metadata.tags.length)}
        canCancel={activeStep === 1 && [
          machineStates.initializing,
          machineStates.uploading,
          machineStates.finishing,
          machineStates.processing,
        ].includes(machine.state)}
        canRetry={machine.state === machineStates.error}
        isUploading={[machineStates.uploading, machineStates.initializing].includes(machine.state)}
        isProcessing={[machineStates.processing, machineStates.finishing].includes(machine.state)}
        isPublishing={machine.state === machineStates.publishing}
        isCancelling={machine.isCancelling}
        disableReason={disableReason}
        onStart={runUploadFlow}
        onContinue={() => detailsValid && setActiveStep(3)}
        onPublish={() => handlePublish(canPublish)}
        onBack={() => setActiveStep((s) => Math.max(1, s - 1))}
        onCancel={handleCancel}
        onReset={handleReset}
        onRetry={() => handleRetry(canPublish)}
        onSaveDraft={() => {}}
        showSaveDraft={activeStep === 2}
        resetLabel={isUploadLocked ? 'Reset upload' : 'Reset'}
        mobileSticky
      />
    </section>
  )
}