"use client"

import { useState } from "react"
import { useRouter } from "next/navigation"
import { useTranslations } from "next-intl"
import { MoreHorizontal, Eye, Pencil, Trash, Archive, UploadCloud, Undo2, Copy, BarChart3 } from "lucide-react"
import { toast } from "sonner"

import { Button } from "@/shared/components/ui/button"
import { ScrollArea } from "@/shared/components/ui/scroll-area"
import {
  DropdownMenu,
  DropdownMenuContent,
  DropdownMenuItem,
  DropdownMenuLabel,
  DropdownMenuSeparator,
  DropdownMenuTrigger,
} from "@/shared/components/ui/dropdown-menu"
import {
  AlertDialog,
  AlertDialogAction,
  AlertDialogCancel,
  AlertDialogContent,
  AlertDialogDescription,
  AlertDialogFooter,
  AlertDialogHeader,
  AlertDialogTitle,
} from "@/shared/components/ui/alert-dialog"
import {
  Dialog,
  DialogContent,
  DialogTitle,
} from "@/shared/components/ui/dialog"

import { deleteExamAction, duplicateExamAction, updateExamAction, getExamPreviewAction } from "../actions"
import { Exam } from "../types"
import { ExamPaperPreview } from "./assembly/exam-paper-preview"
import type { ExamNode } from "./assembly/selected-question-list"
import { createId } from "@paralleldrive/cuid2"
import { useExamHomeworkFeatures } from "@/shared/hooks/use-exam-homework-features"

// Raw structure node shape returned from the DB before hydration
type RawStructureNode = {
  id?: string
  type?: string
  questionId?: string
  score?: number
  title?: string
  children?: RawStructureNode[]
}

// Type guard to narrow unknown structure payload to raw nodes
const isRawStructureNode = (v: unknown): v is RawStructureNode => {
  if (typeof v !== "object" || v === null) return false
  // 从 unknown 收窄为 Record<string, unknown> 以进行字段检查
  const obj = v as Record<string, unknown>
  return typeof obj.type === "string"
}

const isRawStructureArray = (v: unknown): v is RawStructureNode[] =>
  Array.isArray(v) && v.every((item) => isRawStructureNode(item))

interface ExamActionsProps {
  exam: Exam
}

export function ExamActions({ exam }: ExamActionsProps) {
  const router = useRouter()
  const t = useTranslations("examHomework")
  const features = useExamHomeworkFeatures()
  const [showViewDialog, setShowViewDialog] = useState(false)
  const [showDeleteDialog, setShowDeleteDialog] = useState(false)
  const [isWorking, setIsWorking] = useState(false)
  const [previewNodes, setPreviewNodes] = useState<ExamNode[] | null>(null)
  const [loadingPreview, setLoadingPreview] = useState(false)

  const handleView = async () => {
    setLoadingPreview(true)
    setShowViewDialog(true)
    try {
      const result = await getExamPreviewAction(exam.id)
      if (result.success && result.data) {
        const { structure } = result.data

        const hydrate = (nodes: RawStructureNode[]): ExamNode[] => {
          return nodes.map((node) => {
            if (node.type === "question") {
              return {
                // Avoid empty-string fallback that could cause React key collisions
                id: node.id ?? node.questionId ?? createId(),
                type: "question" as const,
                questionId: node.questionId,
                score: node.score,
                // Question content is not available in preview payload; left undefined
              }
            }
            if (node.type === "group") {
              return {
                id: node.id ?? createId(),
                type: "group" as const,
                title: node.title,
                score: node.score,
                children: hydrate(node.children ?? []),
              }
            }
            // Unknown node type: treat as group with no children to avoid runtime crash
            return {
              id: node.id ?? createId(),
              type: "group" as const,
              title: node.title,
              children: [],
            }
          })
        }

        const nodes = isRawStructureArray(structure) ? hydrate(structure) : []
        setPreviewNodes(nodes)
      } else {
        toast.error(t("exam.actions.previewFailed"))
        setShowViewDialog(false)
      }
    } catch {
      toast.error(t("exam.actions.previewFailed"))
      setShowViewDialog(false)
    } finally {
      setLoadingPreview(false)
    }
  }

  const copyId = () => {
    try {
      void navigator.clipboard.writeText(exam.id)
      toast.success(t("exam.actions.idCopied"))
    } catch (error) {
      console.error("[ExamActions]", error instanceof Error ? error.message : String(error))
      toast.error(t("exam.actions.idCopied"))
    }
  }

  const setStatus = async (status: Exam["status"]) => {
    setIsWorking(true)
    try {
      const formData = new FormData()
      formData.set("examId", exam.id)
      formData.set("status", status)
      const result = await updateExamAction(null, formData)
      if (result.success) {
        toast.success(status === "published" ? t("exam.actions.publishSuccess") : status === "archived" ? t("exam.actions.archiveSuccess") : t("exam.actions.draftSuccess"))
        router.refresh()
      } else {
        toast.error(result.message || t("exam.actions.updateFailed"))
      }
    } catch {
      toast.error(t("exam.actions.updateFailed"))
    } finally {
      setIsWorking(false)
    }
  }

  const duplicateExam = async () => {
    setIsWorking(true)
    try {
      const formData = new FormData()
      formData.set("examId", exam.id)
      const result = await duplicateExamAction(null, formData)
      if (result.success && result.data) {
        toast.success(t("exam.actions.duplicateSuccess"))
        router.push(`/teacher/exams/${result.data}/build`)
        router.refresh()
      } else {
        toast.error(result.message || t("exam.actions.duplicateFailed"))
      }
    } catch {
      toast.error(t("exam.actions.duplicateFailed"))
    } finally {
      setIsWorking(false)
    }
  }

  const handleDelete = async () => {
    setIsWorking(true)
    try {
      const formData = new FormData()
      formData.set("examId", exam.id)
      const result = await deleteExamAction(null, formData)
      if (result.success) {
        toast.success(t("exam.actions.deleteSuccess"))
        setShowDeleteDialog(false)
        router.refresh()
      } else {
        toast.error(result.message || t("exam.actions.deleteFailed"))
      }
    } catch {
      toast.error(t("exam.actions.deleteFailed"))
    } finally {
      setIsWorking(false)
    }
  }

  return (
    <>
      <div className="flex items-center gap-1">
        <Button
          variant="ghost"
          size="icon"
          className="h-11 w-11 sm:h-8 sm:w-8 text-muted-foreground hover:text-foreground"
          onClick={(e) => {
            e.stopPropagation()
            handleView()
          }}
          title={t("exam.actions.preview")}
          aria-label={t("exam.actions.preview")}
        >
          <Eye className="h-4 w-4" />
        </Button>
        <DropdownMenu>
          <DropdownMenuTrigger asChild>
            <Button variant="ghost" className="h-11 w-11 sm:h-8 sm:w-8 p-0" aria-label={t("exam.actions.openMenu")}>
              <span className="sr-only">{t("exam.actions.openMenu")}</span>
              <MoreHorizontal className="h-4 w-4" />
            </Button>
          </DropdownMenuTrigger>
          <DropdownMenuContent align="end">
            <DropdownMenuLabel>{t("exam.actions.copyId")}</DropdownMenuLabel>
            <DropdownMenuItem onClick={copyId}>
              <Copy className="mr-2 h-4 w-4" /> {t("exam.actions.copyId")}
            </DropdownMenuItem>
            <DropdownMenuSeparator />
            {features.canBuild && (
              <DropdownMenuItem onClick={() => router.push(`/teacher/exams/${exam.id}/build`)}>
                <Pencil className="mr-2 h-4 w-4" /> {t("exam.actions.edit")}
              </DropdownMenuItem>
            )}
            {features.canBuild && (
              <DropdownMenuItem onClick={() => router.push(`/teacher/exams/${exam.id}/build`)}>
                <MoreHorizontal className="mr-2 h-4 w-4" /> {t("exam.actions.build")}
              </DropdownMenuItem>
            )}
            {features.canViewStats && (
              <DropdownMenuItem onClick={() => router.push(`/teacher/exams/${exam.id}/analytics`)}>
                <BarChart3 className="mr-2 h-4 w-4" /> {t("exam.analytics.viewAnalytics")}
              </DropdownMenuItem>
            )}
          {features.canCreate && (
            <>
              <DropdownMenuSeparator />
              <DropdownMenuItem onClick={duplicateExam} disabled={isWorking}>
                <Copy className="mr-2 h-4 w-4" /> {t("exam.actions.duplicate")}
              </DropdownMenuItem>
            </>
          )}
          {features.canPublish && (
            <>
              <DropdownMenuSeparator />
              <DropdownMenuItem
                onClick={() => setStatus("published")}
                disabled={isWorking || exam.status === "published"}
              >
                <UploadCloud className="mr-2 h-4 w-4" /> {t("exam.actions.publish")}
              </DropdownMenuItem>
              <DropdownMenuItem
                onClick={() => setStatus("draft")}
                disabled={isWorking || exam.status === "draft"}
              >
                <Undo2 className="mr-2 h-4 w-4" /> {t("exam.actions.moveToDraft")}
              </DropdownMenuItem>
              <DropdownMenuItem
                onClick={() => setStatus("archived")}
                disabled={isWorking || exam.status === "archived"}
              >
                <Archive className="mr-2 h-4 w-4" /> {t("exam.actions.archive")}
              </DropdownMenuItem>
            </>
          )}
          {features.canManage && (
            <>
              <DropdownMenuSeparator />
              <DropdownMenuItem
                className="text-destructive focus:text-destructive"
                onClick={() => setShowDeleteDialog(true)}
                disabled={isWorking}
              >
                <Trash className="mr-2 h-4 w-4" /> {t("exam.actions.delete")}
              </DropdownMenuItem>
            </>
          )}
        </DropdownMenuContent>
      </DropdownMenu>
      </div>

      <AlertDialog open={showDeleteDialog} onOpenChange={setShowDeleteDialog}>
        <AlertDialogContent>
          <AlertDialogHeader>
            <AlertDialogTitle>{t("exam.actions.deleteConfirmTitle")}</AlertDialogTitle>
            <AlertDialogDescription>
              {t("exam.actions.deleteConfirmDescription", { title: exam.title })}
            </AlertDialogDescription>
          </AlertDialogHeader>
          <AlertDialogFooter>
            <AlertDialogCancel>{t("exam.actions.cancel")}</AlertDialogCancel>
            <AlertDialogAction
              className="bg-destructive text-destructive-foreground hover:bg-destructive/90"
              onClick={(e) => {
                e.preventDefault()
                handleDelete()
              }}
              disabled={isWorking}
            >
              {t("exam.actions.delete")}
            </AlertDialogAction>
          </AlertDialogFooter>
        </AlertDialogContent>
      </AlertDialog>

      <Dialog open={showViewDialog} onOpenChange={setShowViewDialog}>
        <DialogContent className="max-w-4xl h-[90vh] flex flex-col p-0 gap-0">
            <div className="p-4 border-b shrink-0 flex items-center justify-between">
               <DialogTitle className="text-lg font-semibold tracking-tight">{exam.title}</DialogTitle>
            </div>
            <ScrollArea className="flex-1">
                {loadingPreview ? (
                    <div className="py-20 text-center text-muted-foreground">{t("exam.actions.loadingPreview")}</div>
                ) : previewNodes && previewNodes.length > 0 ? (
                    <div className="max-w-3xl mx-auto py-8 px-6">
                        <ExamPaperPreview
                            title={exam.title}
                            subject={exam.subject}
                            grade={exam.grade}
                            durationMin={exam.durationMin}
                            totalScore={exam.totalScore}
                            nodes={previewNodes}
                        />
                    </div>
                ) : (
                    <div className="py-20 text-center text-muted-foreground">
                        {t("exam.actions.noQuestions")}
                    </div>
                )}
            </ScrollArea>
        </DialogContent>
      </Dialog>
    </>
  )
}
