import { supabase } from '@/lib/supabase'

const ANSWER_VALUES = ['A', 'B', 'C', 'D'] as const

interface TestResultData {
  testId: number | null
  selectedParts: number[]
  score: number
  total: number
  timeUsed: number
  answers: { questionId: number; selected: number | null; correct: boolean }[]
}

/** Fire-and-forget: save test result. Failures are logged but don't block UI. */
export async function saveTestResult(userId: string, data: TestResultData): Promise<void> {
  const { data: attempt, error: attemptError } = await supabase
    .from('user_test_attempt')
    .insert({
      user_id: userId,
      test_id: data.testId,
      selected_parts: data.selectedParts,
      time_limit_minutes: 10,
      submitted_at: new Date().toISOString(),
      time_spent_seconds: data.timeUsed,
      total_correct: data.score,
      total_questions: data.total,
    })
    .select('id')
    .single()

  if (attemptError) {
    console.error('Failed to save test attempt:', attemptError.message)
    return
  }

  const answerRows = data.answers.map(a => ({
    attempt_id: attempt.id,
    question_id: a.questionId,
    selected_value: a.selected !== null ? ANSWER_VALUES[a.selected] : null,
    is_correct: a.correct,
  }))

  const { error: answersError } = await supabase.from('user_answer').insert(answerRows)
  if (answersError) console.error('Failed to save answers:', answersError.message)
}

/** Fire-and-forget: save writing submission with AI feedback. */
export async function saveWritingSubmission(
  userId: string,
  content: string,
  feedback: object,
): Promise<void> {
  const { error } = await supabase.from('writing_submissions').insert({
    user_id: userId,
    content,
    feedback,
  })
  if (error) console.error('Failed to save writing submission:', error.message)
}

/** Count today's writing submissions for server-side rate limiting (authenticated users). */
export async function countTodayWritingSubmissions(userId: string): Promise<number> {
  const today = new Date().toISOString().split('T')[0]
  const { count, error } = await supabase
    .from('writing_submissions')
    .select('*', { count: 'exact', head: true })
    .eq('user_id', userId)
    .gte('created_at', `${today}T00:00:00.000Z`)
  if (error) return 0
  return count ?? 0
}

/** Fetch test history for a user (most recent first, max 20). */
export async function fetchTestHistory(userId: string) {
  const { data, error } = await supabase
    .from('user_test_attempt')
    .select('id, selected_parts, time_spent_seconds, total_correct, total_questions, score, submitted_at, created_at')
    .eq('user_id', userId)
    .order('created_at', { ascending: false })
    .limit(20)
  if (error) throw error
  return data ?? []
}

/** Fetch writing history for a user (most recent first, max 20). */
export async function fetchWritingHistory(userId: string) {
  const { data, error } = await supabase
    .from('writing_submissions')
    .select('id, content, feedback, created_at')
    .eq('user_id', userId)
    .order('created_at', { ascending: false })
    .limit(20)
  if (error) throw error
  return data ?? []
}