"use client"

import type { HomeworkAssignmentQuestionAnalytics } from "@/modules/homework/types"
import { ScrollArea } from "@/shared/components/ui/scroll-area"

const isRecord = (v: unknown): v is Record<string, unknown> => typeof v === "object" && v !== null

const getOptions = (content: unknown): Array<{ id: string; text: string }> => {
  if (!isRecord(content)) return []
  const raw = content.options
  if (!Array.isArray(raw)) return []
  const out: Array<{ id: string; text: string }> = []
  for (const item of raw) {
    if (!isRecord(item)) continue
    const id = typeof item.id === "string" ? item.id : ""
    const text = typeof item.text === "string" ? item.text : ""
    if (!id || !text) continue
    out.push({ id, text })
  }
  return out
}

const safeInlineJson = (v: unknown) => {
  try {
    const s = JSON.stringify(v)
    if (typeof s === "string" && s.length > 180) return `${s.slice(0, 180)}…`
    return s ?? String(v)
  } catch {
    return String(v)
  }
}

const formatAnswer = (answerContent: unknown, question: HomeworkAssignmentQuestionAnalytics | null) => {
  if (isRecord(answerContent) && "answer" in answerContent) answerContent = answerContent.answer
  if (answerContent === null || answerContent === undefined) return "未作答"
  const options = getOptions(question?.questionContent ?? null)
  const optionTextById = new Map(options.map((o) => [o.id, o.text] as const))

  if (typeof answerContent === "boolean") return answerContent ? "True" : "False"
  if (typeof answerContent === "string") return optionTextById.get(answerContent) ?? answerContent
  if (Array.isArray(answerContent)) {
    const parts = answerContent
      .map((x) => (typeof x === "string" ? optionTextById.get(x) ?? x : x))
      .map((x) => (typeof x === "string" ? x : safeInlineJson(x)))
    return parts.join(", ")
  }
  return safeInlineJson(answerContent)
}

const clamp01 = (v: number) => Math.max(0, Math.min(1, v))

function ErrorRatePieChart({ errorRate }: { errorRate: number }) {
  const pct = clamp01(errorRate) * 100
  const r = 15.91549430918954
  const dashA = pct
  const dashB = 100 - pct
  const showError = pct > 0

  return (
    <svg viewBox="0 0 36 36" className="size-12" role="img" aria-label={`错误率 ${pct.toFixed(1)}%`}>
      <circle cx="18" cy="18" r={r} fill="none" strokeWidth="3.5" className="stroke-border" />
      <circle cx="18" cy="18" r={r} fill="none" strokeWidth="3.5" className="stroke-chart-2" />
      {showError ? (
        <circle
          cx="18"
          cy="18"
          r={r}
          fill="none"
          strokeWidth="3.5"
          strokeLinecap="round"
          strokeDasharray={`${dashA} ${dashB}`}
          transform="rotate(-90 18 18)"
          className="stroke-destructive"
        />
      ) : null}
      <text x="18" y="19.2" textAnchor="middle" className="fill-foreground text-[8px] font-medium tabular-nums">
        {pct.toFixed(0)}%
      </text>
    </svg>
  )
}

export function HomeworkAssignmentQuestionErrorDetailPanel({
  selected,
  gradedSampleCount,
}: {
  selected: HomeworkAssignmentQuestionAnalytics | null
  gradedSampleCount: number
}) {
  const wrongAnswers = selected?.wrongAnswers ?? []
  const errorCount = selected?.errorCount ?? 0
  const errorRate = selected?.errorRate ?? 0

  return (
    <div className="flex h-full flex-col overflow-hidden bg-muted/5">
      <div className="border-b px-6 py-4 bg-muted/5">
        <div className="text-sm font-medium">Error Analysis</div>
      </div>
      <ScrollArea className="flex-1">
        <div className="p-6 space-y-6">
          {selected ? (
            <>
              <div className="flex items-center gap-4 p-4 bg-background rounded-lg border shadow-sm">
                <div className="shrink-0">
                  <ErrorRatePieChart errorRate={errorRate} />
                </div>
                <div className="min-w-0 flex-1 grid gap-1">
                  <div className="flex items-center justify-between text-sm">
                    <span className="text-muted-foreground">Question</span>
                    <span className="font-medium">Q{selected.questionId.slice(-4)}</span>
                  </div>
                  <div className="flex items-center justify-between text-sm">
                    <span className="text-muted-foreground">Errors</span>
                    <span className="font-medium text-destructive">
                      {errorCount} <span className="text-muted-foreground text-xs">/ {gradedSampleCount}</span>
                    </span>
                  </div>
                </div>
              </div>

              <div className="space-y-4">
                <div className="text-xs font-medium text-muted-foreground uppercase tracking-wider">Wrong Answers ({wrongAnswers.length})</div>
                {wrongAnswers.length === 0 ? (
                  <div className="text-sm text-muted-foreground italic py-4 text-center bg-background rounded-md border border-dashed">
                    No wrong answers recorded.
                  </div>
                ) : (
                  <div className="space-y-3">
                    {wrongAnswers.map((wa, i) => (
                      <div key={i} className="rounded-md border bg-background p-3 text-sm shadow-sm">
                        <div className="mb-1 flex items-center justify-between">
                          <span className="text-xs font-medium text-muted-foreground">Student Answer</span>
                          <span className="text-xs text-muted-foreground">{wa.count ?? 1} student{(wa.count ?? 1) > 1 ? "s" : ""}</span>
                        </div>
                        <div className="font-medium text-destructive break-words">
                          {formatAnswer(wa.answerContent, selected)}
                        </div>
                      </div>
                    ))}
                  </div>
                )}
              </div>
            </>
          ) : (
            <div className="flex h-full flex-col items-center justify-center text-center text-muted-foreground py-12">
              <p>Select a question from the left</p>
              <p className="text-xs mt-1">to view error analysis</p>
            </div>
          )}
        </div>
      </ScrollArea>
    </div>
  )
}