import { useState } from 'react'
import type { Exam, ExamState } from '../types'
import { gradeQuestion } from '../utils/grading'
import { formatTime } from '../utils/formatting'
import Tex from './Tex'
import QuestionMedia from './QuestionMedia'
import QuestionRenderer from './questions/QuestionRenderer'

interface Props {
  exam: Exam
  state: ExamState
  onRestart: () => void
  onExit: () => void
  reviewOnly?: boolean
}

export default function Results({ exam, state, onRestart, onExit, reviewOnly }: Props) {
  const { answers, startedAt, completedAt } = state
  const elapsedMs = (completedAt ?? Date.now()) - startedAt

  const graded = exam.questions.map((q) => ({
    q,
    userAnswer: answers[q.id],
    result: gradeQuestion(q, answers[q.id]),
  }))

  const totalPoints = exam.questions.reduce((a, q) => a + (q.points ?? 1), 0)
  const scorePoints = graded.reduce((a, g) => a + g.result.points, 0)
  const gradedCount = graded.filter((g) => g.result.status !== 'ungraded').length
  const correctCount = graded.filter((g) => g.result.correct).length
  const pct = totalPoints ? Math.round((scorePoints / totalPoints) * 100) : 0
  const passing = exam.passingScore ?? 60
  const passed = pct >= passing

  const byCat: Record<string, { earned: number; possible: number; correct: number; total: number }> = {}
  graded.forEach((g) => {
    const cat = g.q.category ?? 'Uncategorized'
    if (!byCat[cat]) byCat[cat] = { earned: 0, possible: 0, correct: 0, total: 0 }
    byCat[cat].possible += g.q.points ?? 1
    byCat[cat].earned += g.result.points
    byCat[cat].total += 1
    if (g.result.correct) byCat[cat].correct += 1
  })

  const [openIdx, setOpenIdx] = useState<number | null>(null)

  return (
    <div className="results">
      <div className="results-eyebrow">
        {reviewOnly ? 'Reviewing past attempt' : 'Exam complete'} · {exam.title}
      </div>
      <h1 className="results-title">
        You scored <em>{pct}%</em><br />
        <span style={{ fontSize: '0.5em', color: 'var(--ink-3)' }}>
          {passed
            ? `Above the ${passing}% passing mark.`
            : `Below the ${passing}% passing mark. Keep practicing.`}
        </span>
      </h1>

      <div className="score-grid">
        <div className="score-cell">
          <div className="score-cell-label">Points</div>
          <div className="score-cell-value">{scorePoints}<span className="score-cell-unit">/ {totalPoints}</span></div>
        </div>
        <div className="score-cell" style={{ paddingLeft: 24 }}>
          <div className="score-cell-label">Correct</div>
          <div className="score-cell-value">{correctCount}<span className="score-cell-unit">/ {gradedCount}</span></div>
        </div>
        <div className="score-cell" style={{ paddingLeft: 24 }}>
          <div className="score-cell-label">Time</div>
          <div className="score-cell-value mono" style={{ fontSize: 36 }}>{formatTime(elapsedMs)}</div>
        </div>
      </div>

      {Object.keys(byCat).length > 1 && (
        <div className="category-breakdown">
          <div style={{ fontFamily: 'var(--font-mono)', fontSize: 11, textTransform: 'uppercase', letterSpacing: '0.12em', color: 'var(--ink-3)', marginBottom: 16, fontWeight: 500 }}>
            By category
          </div>
          {Object.entries(byCat).map(([cat, c]) => {
            const catPct = c.possible ? Math.round((c.earned / c.possible) * 100) : 0
            return (
              <div key={cat} className="category-row">
                <div style={{ fontWeight: 500 }}>{cat}</div>
                <div className="category-bar"><div style={{ width: `${catPct}%` }} /></div>
                <div className="category-score">{catPct}%</div>
              </div>
            )
          })}
        </div>
      )}

      <h2 className="review-heading">Review</h2>
      {graded.map((g, i) => {
        const promptText = g.q.prompt
          .replace(/\$\$([^$]+)\$\$/g, '[math]')
          .replace(/\$([^$]+)\$/g, '[math]')
        return (
          <div key={g.q.id} className={`review-item${openIdx === i ? ' open' : ''}`}>
            <div className="review-item-header" onClick={() => setOpenIdx(openIdx === i ? null : i)}>
              <span className="review-num">{String(i + 1).padStart(2, '0')}</span>
              <span className="review-title">
                <Tex>{promptText.slice(0, 90)}</Tex>
                {promptText.length > 90 ? '…' : ''}
              </span>
              <span className={`review-status ${g.result.status}`}>{g.result.status}</span>
              <span style={{ color: 'var(--ink-4)' }}>{openIdx === i ? '−' : '+'}</span>
            </div>
            {openIdx === i && (
              <div className="review-body">
                <div className="q-prompt" style={{ fontSize: 20, marginBottom: 20 }}>
                  <Tex>{g.q.prompt}</Tex>
                </div>
                <QuestionMedia q={g.q} />
                <QuestionRenderer q={g.q} value={g.userAnswer} onChange={() => {}} locked graded />
                {g.q.explanation && (
                  <div className="feedback" style={{ marginTop: 24 }}>
                    <div className="feedback-label">Explanation</div>
                    <div className="feedback-body"><Tex>{g.q.explanation}</Tex></div>
                  </div>
                )}
                {g.q.rubric && (
                  <div style={{ marginTop: 20, fontSize: 13.5 }}>
                    <div className="meta-label" style={{ marginBottom: 8 }}>Rubric (self-grade)</div>
                    <ul style={{ paddingLeft: 18, margin: 0, lineHeight: 1.7, color: 'var(--ink-2)' }}>
                      {g.q.rubric.map((r, j) => <li key={j}><Tex>{r}</Tex></li>)}
                    </ul>
                  </div>
                )}
              </div>
            )}
          </div>
        )
      })}

      <div style={{ marginTop: 48, display: 'flex', gap: 12 }}>
        {!reviewOnly && <button className="btn btn-primary" onClick={onRestart}>Retake exam</button>}
        <button className="btn" onClick={onExit}>Back to home</button>
      </div>
    </div>
  )
}