'use client'

import Select from '@/components/ui/Select'

import { useCallback, useEffect, useMemo, useRef, useState } from 'react'
import { useRouter, useSearchParams } from 'next/navigation'
import { useSession } from 'next-auth/react'
import ToastBubble from '@/components/ToastBubble'
import { useToast } from '@/hooks/useToast'
import {
  createWorkReviewProject,
  createWorkReviewVersion,
  deleteWorkReviewProject,
  getWorkReviewBoard,
  submitWorkReview,
  WorkReviewRequestError,
} from '@/lib/work-review-client'
import type {
  WorkReviewBoardData,
  WorkReviewProject,
  WorkReviewReviewInput,
  WorkReviewStatus,
  WorkReviewSubmissionInput,
} from '@/types/work-review'
import { WorkReviewDeleteConfirmationDialog, WorkReviewSubmissionDialog } from './WorkReviewDialogs'
import { WorkReviewHeader } from './WorkReviewHeader'
import { WorkReviewProjectCard } from './WorkReviewProjectCard'
import { WorkReviewReviewerWorkspace } from './WorkReviewReviewerWorkspace'
import { canResubmitWorkReviewProject } from '@/lib/work-review-policy'

const statusOptions: Array<{ value: WorkReviewStatus | ''; label: string }> = [
  { value: '', label: '全部状态' },
  { value: 'pending_review', label: '评审中' },
  { value: 'revision_required', label: '待修改' },
  { value: 'approved', label: '已通过' },
]

function normalizeStatus(value: string | null): WorkReviewStatus | '' {
  return ['pending_review', 'revision_required', 'approved'].includes(String(value || ''))
    ? value as WorkReviewStatus
    : ''
}

function normalizePage(value: string | null) {
  return Math.max(1, Number(value || 1) || 1)
}

function LoadingScreen() {
  return (
    <div className="min-h-screen bg-[#fafafa]">
      <div className="h-16 border-b border-[#e7e8ea] bg-[#fafafa]" />
      <main className="mx-auto max-w-[1180px] px-4 py-8 sm:px-6">
        <div className="h-8 w-48 animate-pulse bg-[#eceef0]" />
        <div className="mt-3 h-4 w-72 animate-pulse bg-[#f2f3f5]" />
        <div className="mt-8 grid gap-3 sm:grid-cols-3">
          {[0, 1, 2].map((item) => <div key={item} className="h-20 animate-pulse rounded-xl bg-white" />)}
        </div>
        <div className="mt-6 space-y-3">
          {[0, 1, 2].map((item) => <div key={item} className="h-32 animate-pulse rounded-xl bg-white" />)}
        </div>
      </main>
    </div>
  )
}

export default function WorkReviewBoard() {
  const { data: session, status: sessionStatus } = useSession()
  const router = useRouter()
  const searchParams = useSearchParams()
  const initialQueryRef = useRef(searchParams.get('query') || '')
  const initialStatusRef = useRef(normalizeStatus(searchParams.get('status')))
  const initialPageRef = useRef(normalizePage(searchParams.get('page')))
  const initialProjectRef = useRef(searchParams.get('project') || '')
  const deepLinkProjectRef = useRef(initialProjectRef.current)
  const requestSequenceRef = useRef(0)
  const abortRef = useRef<AbortController | null>(null)
  const [query, setQuery] = useState(initialQueryRef.current)
  const [debouncedQuery, setDebouncedQuery] = useState(initialQueryRef.current)
  const [statusFilter, setStatusFilter] = useState<WorkReviewStatus | ''>(initialStatusRef.current)
  const [page, setPage] = useState(initialPageRef.current)
  const [data, setData] = useState<WorkReviewBoardData | null>(null)
  const [loading, setLoading] = useState(true)
  const [error, setError] = useState<string | null>(null)
  const [deepLinkedProjectMissing, setDeepLinkedProjectMissing] = useState(false)
  const [expandedProjectId, setExpandedProjectId] = useState(initialProjectRef.current)
  const [submissionDialog, setSubmissionDialog] = useState<{
    mode: 'create' | 'resubmit'
    project?: WorkReviewProject
  } | null>(null)
  const [deletionDialogProject, setDeletionDialogProject] = useState<WorkReviewProject | null>(null)
  const [deletionBusy, setDeletionBusy] = useState(false)
  const [deletionError, setDeletionError] = useState<string | null>(null)
  const { toast, showToast } = useToast()

  useEffect(() => {
    const timer = window.setTimeout(() => {
      setDebouncedQuery(query.trim())
      setPage(1)
    }, 300)
    return () => window.clearTimeout(timer)
  }, [query])

  useEffect(() => {
    if (sessionStatus !== 'unauthenticated') return
    const currentPath = typeof window === 'undefined'
      ? '/work-review'
      : `${window.location.pathname}${window.location.search}`
    router.replace(`/login?redirect=${encodeURIComponent(currentPath)}`)
  }, [router, sessionStatus])

  const updateUrl = useCallback((input?: { project?: string; replaceProject?: boolean }) => {
    const params = new URLSearchParams()
    if (debouncedQuery) params.set('query', debouncedQuery)
    if (statusFilter) params.set('status', statusFilter)
    if (page > 1) params.set('page', String(page))
    const projectId = input?.replaceProject
      ? input.project || ''
      : expandedProjectId
    if (projectId) params.set('project', projectId)
    const value = params.toString()
    router.replace(`/work-review${value ? `?${value}` : ''}`, { scroll: false })
  }, [debouncedQuery, expandedProjectId, page, router, statusFilter])

  useEffect(() => {
    if (sessionStatus !== 'authenticated') return
    updateUrl()
  }, [sessionStatus, updateUrl])

  const load = useCallback(async (options?: { board?: boolean }) => {
    if (sessionStatus !== 'authenticated') return
    const sequence = requestSequenceRef.current + 1
    requestSequenceRef.current = sequence
    abortRef.current?.abort()
    const controller = new AbortController()
    abortRef.current = controller
    setLoading(true)
    setError(null)
    try {
      const deepLinkProject = options?.board ? '' : deepLinkProjectRef.current
      const nextData = await getWorkReviewBoard({
        query: options?.board ? '' : debouncedQuery,
        status: options?.board ? '' : statusFilter,
        project: deepLinkProject,
        page: options?.board ? 1 : page,
        pageSize: 20,
      }, controller.signal)
      if (sequence !== requestSequenceRef.current) return
      if (deepLinkProject) {
        setDeepLinkedProjectMissing(!nextData.items.some((item) => item.id === deepLinkProject))
        deepLinkProjectRef.current = ''
      } else {
        setDeepLinkedProjectMissing(false)
      }
      setData(nextData)
    } catch (loadError) {
      if (controller.signal.aborted || sequence !== requestSequenceRef.current) return
      if (loadError instanceof WorkReviewRequestError && loadError.status === 401) {
        const currentPath = `${window.location.pathname}${window.location.search}`
        router.replace(`/login?redirect=${encodeURIComponent(currentPath)}`)
        return
      }
      setError(loadError instanceof Error ? loadError.message : '看板加载失败')
    } finally {
      if (sequence === requestSequenceRef.current) setLoading(false)
    }
  }, [debouncedQuery, page, router, sessionStatus, statusFilter])

  useEffect(() => {
    void load()
    return () => {
      requestSequenceRef.current += 1
      abortRef.current?.abort()
    }
  }, [load])

  useEffect(() => {
    if (!expandedProjectId || !data?.items.some((item) => item.id === expandedProjectId)) return
    const frame = window.requestAnimationFrame(() => {
      document.getElementById(`work-review-project-${expandedProjectId}`)?.scrollIntoView({
        block: 'start',
        behavior: 'smooth',
      })
    })
    return () => window.cancelAnimationFrame(frame)
  }, [data?.items, expandedProjectId])

  const replaceProject = useCallback((project: WorkReviewProject) => {
    setData((current) => current ? {
      ...current,
      items: current.items.map((item) => item.id === project.id ? project : item),
    } : current)
  }, [])

  const submitProject = async (input: WorkReviewSubmissionInput) => {
    const project = await createWorkReviewProject(input)
    setStatusFilter('')
    setQuery('')
    setDebouncedQuery('')
    setPage(1)
    setData((current) => current ? {
      ...current,
      items: [project, ...current.items.filter((item) => item.id !== project.id)].slice(0, current.pagination.pageSize),
      pagination: { ...current.pagination, page: 1, total: current.pagination.total + 1 },
    } : current)
    setExpandedProjectId(project.id)
    setSubmissionDialog(null)
    showToast('作品已提交，评审通知正在发送')
  }

  const submitVersion = async (projectId: string, input: WorkReviewSubmissionInput) => {
    const project = await createWorkReviewVersion(projectId, input)
    replaceProject(project)
    setExpandedProjectId(project.id)
    setSubmissionDialog(null)
    showToast(`V${project.latestVersion} 已提交，评审通知正在发送`)
  }

  const submitReview = async (versionId: string, input: WorkReviewReviewInput) => {
    const project = await submitWorkReview(versionId, input)
    replaceProject(project)
    setExpandedProjectId(project.id)
    if (project.status === 'approved') {
      showToast('评审已完成，作品通过结果已通知发起人')
    } else if (project.status === 'revision_required') {
      showToast('评审已完成，修改意见已通知发起人')
    } else {
      showToast('评审意见已提交，等待另一位评审完成')
    }
  }

  const confirmDeleteProject = async () => {
    if (!deletionDialogProject || deletionBusy) return
    const project = deletionDialogProject
    setDeletionBusy(true)
    setDeletionError(null)
    try {
      await deleteWorkReviewProject(project.id)
      const shouldGoToPreviousPage = Boolean(data && data.items.length === 1 && page > 1)
      setData((current) => current ? {
        ...current,
        items: current.items.filter((item) => item.id !== project.id),
        pagination: {
          ...current.pagination,
          total: Math.max(0, current.pagination.total - 1),
          totalPages: Math.max(1, Math.ceil(Math.max(0, current.pagination.total - 1) / current.pagination.pageSize)),
        },
      } : current)
      if (expandedProjectId === project.id) {
        setExpandedProjectId('')
        updateUrl({ project: '', replaceProject: true })
      }
      setDeletionDialogProject(null)
      showToast(`作品「${project.title}」已删除`)
      if (shouldGoToPreviousPage) {
        setPage((current) => Math.max(1, current - 1))
      } else {
        void load()
      }
    } catch (deleteError) {
      setDeletionError(deleteError instanceof Error ? deleteError.message : '删除失败，请重试')
    } finally {
      setDeletionBusy(false)
    }
  }

  const pageStats = useMemo(() => {
    const items = data?.items || []
    return {
      action: items.filter((item) => item.permissions.canResubmit || item.permissions.pendingReviewRoles.length > 0).length,
      pending: items.filter((item) => item.status === 'pending_review').length,
      revision: items.filter((item) => item.status === 'revision_required').length,
      approved: items.filter((item) => item.status === 'approved').length,
    }
  }, [data?.items])

  if (sessionStatus === 'loading' || (sessionStatus === 'authenticated' && !data && loading)) {
    return <LoadingScreen />
  }
  if (sessionStatus === 'unauthenticated' || !session) return null

  const me = data?.me
  const canSubmit = Boolean(me?.permissions.canSubmit)
  const canDeleteProjects = Boolean(me?.permissions.canDeleteProjects)
  const requestedProject = expandedProjectId
    ? data?.items.find((item) => item.id === expandedProjectId)
    : null
  // 看板接口已经按当前用户做过可见范围过滤；所有可见作品都使用同一套详情工作区。
  // 具体的评审、批注和提交修改按钮仍由项目 permissions 单独控制。
  const focusedProject = requestedProject
  const canResubmitFocusedProject = focusedProject
    ? canResubmitWorkReviewProject(focusedProject)
    : false

  if (focusedProject) {
    return (
      <div className="min-h-screen bg-[#fafafa] text-[#1a1c1d]">
        <WorkReviewHeader
          name={me?.user.name || session.user?.name || '当前用户'}
          avatar={me?.user.avatar || (session.user as any)?.avatar || null}
          wide
          secondaryAction={canResubmitFocusedProject ? {
            label: '提交修改',
            icon: 'add',
            onClick: () => setSubmissionDialog({ mode: 'resubmit', project: focusedProject }),
          } : undefined}
          primaryAction={{
            label: '返回看板',
            icon: 'back',
            onClick: () => {
              deepLinkProjectRef.current = ''
              setExpandedProjectId('')
              setQuery('')
              setDebouncedQuery('')
              setStatusFilter('')
              setPage(1)
              router.replace('/work-review', { scroll: false })
              void load({ board: true })
            },
          }}
        />
        <main className="mx-auto w-full max-w-[1600px] px-3 py-3 sm:px-5 sm:py-4">
          <WorkReviewReviewerWorkspace
            project={focusedProject}
            onSubmitReview={(version, input) => submitReview(version.id, input)}
          />
        </main>

        {submissionDialog && (
          <WorkReviewSubmissionDialog
            key={`${submissionDialog.mode}-${submissionDialog.project?.id || 'new'}-${submissionDialog.project?.latestVersion || 0}`}
            mode={submissionDialog.mode}
            project={submissionDialog.project}
            onClose={() => setSubmissionDialog(null)}
            onSubmit={(input) => submissionDialog.mode === 'create'
              ? submitProject(input)
              : submitVersion(submissionDialog.project!.id, input)}
          />
        )}
        {toast?.show && <ToastBubble message={toast.message} variant={toast.variant} topOffsetClass="top-20" zIndexClass="z-[1300]" />}
      </div>
    )
  }

  return (
    <div className="min-h-screen bg-[#fafafa] text-[#1a1c1d]">
      <WorkReviewHeader
        name={me?.user.name || session.user?.name || '当前用户'}
        avatar={me?.user.avatar || (session.user as any)?.avatar || null}
        primaryAction={canSubmit ? {
          label: '提交作品',
          icon: 'add',
          onClick: () => setSubmissionDialog({ mode: 'create' }),
        } : undefined}
      />

      <main className="mx-auto w-full max-w-[1180px] px-4 py-7 pb-16 sm:px-6 sm:py-9">
        <section className="flex flex-col gap-4 sm:flex-row sm:items-end sm:justify-between">
          <div>
            <h1 className="text-[24px] font-bold tracking-tight text-[#101828]">作品与评审记录</h1>
            <p className="mt-1.5 text-[13px] font-medium text-[#667085]">
              同一作品的所有提交版本与评审意见会归档在一张卡片中
            </p>
          </div>
          {data && (
            <div className="text-[12px] font-semibold text-[#7b8494]">
              共 {data.pagination.total} 个作品
            </div>
          )}
        </section>

        <section className="mt-6 grid grid-cols-2 gap-2 sm:grid-cols-4" aria-label="本页状态概览">
          {[
            { label: '待我操作', value: pageStats.action, tone: 'text-[#0052d9]', filter: '' as const },
            { label: '评审中', value: pageStats.pending, tone: 'text-[#0052d9]', filter: 'pending_review' as const },
            { label: '待修改', value: pageStats.revision, tone: 'text-[#8a5200]', filter: 'revision_required' as const },
            { label: '已通过', value: pageStats.approved, tone: 'text-[#087a3c]', filter: 'approved' as const },
          ].map((item) => (
            <button
              key={item.label}
              type="button"
              onClick={() => {
                setStatusFilter(item.filter)
                setPage(1)
                setExpandedProjectId('')
              }}
              className={`rounded-xl border bg-white px-4 py-3 text-left transition-colors ${
                statusFilter === item.filter && item.label !== '待我操作'
                  ? 'border-[#8ab9ff] ring-1 ring-[#cfe0ff]'
                  : 'border-[#e1e7ef] hover:border-[#b8cae2]'
              }`}
            >
              <div className={`text-[22px] font-bold leading-none ${item.tone}`}>{item.value}</div>
              <div className="mt-1.5 text-[11px] font-semibold text-[#667085]">{item.label} <span className="font-normal text-[#98a2b3]">· 本页</span></div>
            </button>
          ))}
        </section>

        <section className="mt-5 rounded-xl border border-[#e1e7ef] bg-white p-3 sm:p-4" aria-label="作品筛选">
          <div className="grid gap-3 sm:grid-cols-[minmax(0,1fr)_180px_auto]">
            <label className="relative">
              <span className="sr-only">搜索作品</span>
              <svg className="pointer-events-none absolute left-3 top-1/2 h-4 w-4 -translate-y-1/2 text-[#98a2b3]" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2">
                <circle cx="11" cy="11" r="7" />
                <path d="m20 20-3.5-3.5" />
              </svg>
              <input
                value={query}
                onChange={(event) => setQuery(event.target.value)}
                placeholder="搜索作品名称或提交人"
                className="h-11 w-full rounded border border-[#d7dde7] bg-white pl-10 pr-3 text-[13px] outline-none placeholder:text-[#98a2b3] focus:border-[#0050cb] focus:ring-2 focus:ring-[#dcecff]"
              />
            </label>
            <label>
              <span className="sr-only">状态筛选</span>
              <Select
                value={statusFilter}
                onChange={(event) => {
                  setStatusFilter(normalizeStatus(event.target.value))
                  setPage(1)
                  setExpandedProjectId('')
                }}
                className="h-11 w-full rounded border border-[#d7dde7] bg-white px-3 text-[13px] font-semibold text-[#344054] outline-none focus:border-[#0050cb] focus:ring-2 focus:ring-[#dcecff]"
              >
                {statusOptions.map((option) => <option key={option.value} value={option.value}>{option.label}</option>)}
              </Select>
            </label>
            <button
              type="button"
              onClick={() => void load()}
              disabled={loading}
              className="h-11 rounded border border-[#d7dde7] bg-white px-4 text-[12px] font-bold text-[#344054] hover:bg-[#f7f8fa] disabled:opacity-50"
            >
              {loading ? '刷新中...' : '刷新'}
            </button>
          </div>
        </section>

        {deepLinkedProjectMissing && (
          <div className="mt-4 rounded-lg border border-[#f3d29b] bg-[#fffaf0] px-4 py-3 text-[12px] font-semibold leading-5 text-[#8a5200]">
            通知对应的作品不在当前结果页中。请清除筛选后搜索作品名称；如仍未找到，请联系管理员确认访问权限。
          </div>
        )}

        {error && (
          <div className="mt-5 rounded-xl border border-[#f0b8b8] bg-[#fff5f5] px-4 py-4" role="alert">
            <div className="text-[13px] font-bold text-[#b42318]">看板加载失败</div>
            <p className="mt-1 text-[12px] font-medium leading-5 text-[#93000a]">{error}</p>
            <button
              type="button"
              onClick={() => void load()}
              className="mt-3 min-h-9 rounded bg-[#b42318] px-4 text-[12px] font-bold text-white hover:bg-[#931f16]"
            >
              重新加载
            </button>
          </div>
        )}

        {data && !error && (
          <section className={`mt-5 space-y-3 transition-opacity ${loading ? 'opacity-55' : 'opacity-100'}`} aria-busy={loading}>
            {data.items.map((project) => (
              <WorkReviewProjectCard
                key={project.id}
                project={project}
                expanded={expandedProjectId === project.id}
                canDelete={canDeleteProjects}
                deleteBusy={deletionBusy && deletionDialogProject?.id === project.id}
                onToggle={() => {
                  const nextId = expandedProjectId === project.id ? '' : project.id
                  setExpandedProjectId(nextId)
                  updateUrl({ project: nextId, replaceProject: true })
                }}
                onDelete={() => {
                  setDeletionError(null)
                  setDeletionDialogProject(project)
                }}
                onResubmit={() => setSubmissionDialog({ mode: 'resubmit', project })}
                onReview={() => {
                  setExpandedProjectId(project.id)
                  updateUrl({ project: project.id, replaceProject: true })
                }}
              />
            ))}

            {data.items.length === 0 && (
              <div className="rounded-xl border border-dashed border-[#c8d1dd] bg-white px-5 py-14 text-center">
                <div className="mx-auto flex h-12 w-12 items-center justify-center rounded-full bg-[#eef3f8] text-[20px] font-bold text-[#7b8494]">0</div>
                <h2 className="mt-4 text-[17px] font-bold text-[#101828]">
                  {debouncedQuery || statusFilter ? '没有符合条件的作品' : '还没有作品记录'}
                </h2>
                <p className="mt-1.5 text-[12px] font-medium text-[#7b8494]">
                  {debouncedQuery || statusFilter ? '可以调整搜索词或状态筛选' : canSubmit ? '提交第一份作品，开始评审流程' : '有作品分配给你后会显示在这里'}
                </p>
                {(debouncedQuery || statusFilter) ? (
                  <button
                    type="button"
                    onClick={() => {
                      setQuery('')
                      setDebouncedQuery('')
                      setStatusFilter('')
                      setPage(1)
                    }}
                    className="mt-5 min-h-10 rounded border border-[#cfd6e1] px-4 text-[12px] font-bold text-[#344054] hover:bg-[#f7f8fa]"
                  >
                    清除筛选
                  </button>
                ) : canSubmit ? (
                  <button
                    type="button"
                    onClick={() => setSubmissionDialog({ mode: 'create' })}
                    className="mt-5 min-h-10 rounded bg-[#0050cb] px-4 text-[12px] font-bold text-white hover:bg-[#003fa3]"
                  >
                    提交作品
                  </button>
                ) : null}
              </div>
            )}
          </section>
        )}

        {data && data.pagination.totalPages > 1 && (
          <nav className="mt-6 flex items-center justify-center gap-3" aria-label="作品分页">
            <button
              type="button"
              disabled={page <= 1 || loading}
              onClick={() => {
                setExpandedProjectId('')
                setPage((current) => Math.max(1, current - 1))
                window.scrollTo({ top: 0, behavior: 'smooth' })
              }}
              className="min-h-10 rounded border border-[#d7dde7] bg-white px-4 text-[12px] font-bold text-[#344054] hover:bg-[#f7f8fa] disabled:cursor-not-allowed disabled:text-[#b6bdc8]"
            >
              上一页
            </button>
            <span className="min-w-[88px] text-center text-[12px] font-semibold text-[#667085]">
              {data.pagination.page} / {data.pagination.totalPages}
            </span>
            <button
              type="button"
              disabled={page >= data.pagination.totalPages || loading}
              onClick={() => {
                setExpandedProjectId('')
                setPage((current) => Math.min(data.pagination.totalPages, current + 1))
                window.scrollTo({ top: 0, behavior: 'smooth' })
              }}
              className="min-h-10 rounded border border-[#d7dde7] bg-white px-4 text-[12px] font-bold text-[#344054] hover:bg-[#f7f8fa] disabled:cursor-not-allowed disabled:text-[#b6bdc8]"
            >
              下一页
            </button>
          </nav>
        )}
      </main>

      {submissionDialog && (
        <WorkReviewSubmissionDialog
          key={`${submissionDialog.mode}-${submissionDialog.project?.id || 'new'}-${submissionDialog.project?.latestVersion || 0}`}
          mode={submissionDialog.mode}
          project={submissionDialog.project}
          onClose={() => setSubmissionDialog(null)}
          onSubmit={(input) => submissionDialog.mode === 'create'
            ? submitProject(input)
            : submitVersion(submissionDialog.project!.id, input)}
        />
      )}
      {deletionDialogProject && (
        <WorkReviewDeleteConfirmationDialog
          project={deletionDialogProject}
          busy={deletionBusy}
          error={deletionError}
          onClose={() => {
            if (deletionBusy) return
            setDeletionDialogProject(null)
            setDeletionError(null)
          }}
          onConfirm={() => void confirmDeleteProject()}
        />
      )}
      {toast?.show && <ToastBubble message={toast.message} variant={toast.variant} topOffsetClass="top-20" zIndexClass="z-[1300]" />}
    </div>
  )
}