import { Link } from 'react-router-dom'
import { Icon } from '../components/Icon'
import type { IconName } from '../components/Icon'
import { Badge } from '../components/ui'
import type { CourseLevel, LessonType, PublicCourseCard } from '../api/types'

/**
 * Drobne czesci wspolne dla stron Akademii.
 *
 * Kafelek kursu pokazuje sie na stronie glownej, na liscie kursow i w cenniku,
 * a pasek postepu na pulpicie i w odtwarzaczu. Trzy kopie tego samego kafelka
 * rozjechalyby sie przy pierwszej poprawce.
 */

export const LEVEL_LABEL: Record<CourseLevel, string> = {
  BASIC: 'Podstawowy',
  INTERMEDIATE: 'Średniozaawansowany',
  ADVANCED: 'Zaawansowany',
}

export const LESSON_TYPE_LABEL: Record<LessonType, string> = {
  VIDEO: 'Nagranie',
  TEXT: 'Materiał do czytania',
  FILE: 'Plik do pobrania',
  WEBINAR: 'Webinar',
  QUIZ: 'Sprawdzian',
}

export const LESSON_TYPE_ICON: Record<LessonType, IconName> = {
  VIDEO: 'play',
  TEXT: 'file-text',
  FILE: 'download',
  WEBINAR: 'presentation',
  QUIZ: 'list-checks',
}

/**
 * Cena brutto albo oznaczenie kursu darmowego.
 *
 * Brak ceny znaczy "darmowy", a nie "cena zero": to dwie rozne decyzje,
 * rozstrzygniete po stronie backendu przez `Course.isFree()`.
 */
export function formatPrice(price: string | number | null, currency: string) {
  if (price === null || price === undefined) {
    return 'Bezpłatny'
  }
  const value = typeof price === 'string' ? Number(price) : price
  if (!Number.isFinite(value)) {
    return 'Bezpłatny'
  }
  return new Intl.NumberFormat('pl-PL', {
    style: 'currency',
    currency: currency || 'PLN',
    minimumFractionDigits: 2,
  }).format(value)
}

/** Czas trwania w formie, w ktorej mysli czlowiek: godziny i minuty. */
export function formatCourseDuration(minutes: number | null) {
  if (!minutes || minutes <= 0) {
    return null
  }
  const hours = Math.floor(minutes / 60)
  const rest = minutes % 60
  if (hours === 0) {
    return `${rest} min`
  }
  return rest === 0 ? `${hours} godz.` : `${hours} godz. ${rest} min`
}

/** Adres okladki. Pusty identyfikator oznacza kafelek bez obrazka. */
export function mediaUrl(mediaId: number | null) {
  return mediaId ? `/api/public/media/${mediaId}` : null
}

export function CourseCover({
  mediaId,
  title,
  className = '',
}: {
  mediaId: number | null
  title: string
  className?: string
}) {
  const url = mediaUrl(mediaId)
  if (!url) {
    return (
      <div
        className={`flex items-center justify-center bg-gradient-hydro ${className}`}
        aria-hidden="true"
      >
        <Icon name="graduation-cap" size={32} className="text-white/70" />
      </div>
    )
  }
  return (
    <img
      src={url}
      alt={`Okładka kursu ${title}`}
      loading="lazy"
      className={`object-cover ${className}`}
    />
  )
}

/** Kafelek kursu na liscie. */
export function CourseCard({ course }: { course: PublicCourseCard }) {
  const duration = formatCourseDuration(course.durationMinutes)

  return (
    <Link
      to={`/kurs/${course.slug}`}
      className="group flex flex-col overflow-hidden rounded-lg border border-slate-100 bg-white shadow-sm transition-shadow duration-fast ease-standard hover:shadow-md focus-visible:outline-none focus-visible:ring-3 focus-visible:ring-blue-500/45"
    >
      <CourseCover mediaId={course.coverMediaId} title={course.title} className="h-40 w-full" />

      <div className="flex flex-1 flex-col p-4">
        <div className="flex flex-wrap items-center gap-1.5">
          {course.category && <Badge tone="info">{course.category}</Badge>}
          {course.free ? (
            <Badge tone="ok">Bezpłatny</Badge>
          ) : (
            <Badge tone="brand">{formatPrice(course.priceGross, course.currency)}</Badge>
          )}
        </div>

        <h3 className="mt-2.5 text-base font-semibold leading-snug text-slate-900 group-hover:text-blue-600">
          {course.title}
        </h3>
        {course.subtitle && (
          <p className="mt-1 line-clamp-2 text-sm leading-relaxed text-slate-600">
            {course.subtitle}
          </p>
        )}

        <div className="mt-auto flex flex-wrap items-center gap-x-4 gap-y-1.5 pt-3 text-xs text-slate-500">
          <span className="flex items-center gap-1.5">
            <Icon name="book-open" size={14} />
            <span className="hx-data">{course.lessonCount}</span>
            {lessonWord(course.lessonCount)}
          </span>
          {duration && (
            <span className="flex items-center gap-1.5">
              <Icon name="clock" size={14} />
              <span className="hx-data">{duration}</span>
            </span>
          )}
          {course.level && <span>{LEVEL_LABEL[course.level]}</span>}
          {course.certificateEnabled && (
            <span className="flex items-center gap-1.5 text-blue-600">
              <Icon name="award" size={14} />
              Certyfikat
            </span>
          )}
        </div>
      </div>
    </Link>
  )
}

/** Odmiana slowa "lekcja" przez liczbe: 1 lekcja, 2 lekcje, 5 lekcji. */
export function lessonWord(count: number) {
  if (count === 1) return 'lekcja'
  const rest10 = count % 10
  const rest100 = count % 100
  if (rest10 >= 2 && rest10 <= 4 && (rest100 < 12 || rest100 > 14)) return 'lekcje'
  return 'lekcji'
}

/** Pasek postepu kursu. Liczba pochodzi z backendu, z lekcji wymaganych. */
export function ProgressBar({
  percent,
  label,
  className = '',
}: {
  percent: number
  label?: string
  className?: string
}) {
  const safe = Math.max(0, Math.min(100, percent))
  return (
    <div className={className}>
      {label && (
        <div className="mb-1.5 flex items-center justify-between text-xs text-slate-600">
          <span>{label}</span>
          <span className="hx-data font-medium text-slate-900">{safe}%</span>
        </div>
      )}
      <div
        className="h-2 overflow-hidden rounded-full bg-slate-100"
        role="progressbar"
        aria-valuenow={safe}
        aria-valuemin={0}
        aria-valuemax={100}
        aria-label={label || 'Postęp kursu'}
      >
        <div
          className="h-full rounded-full bg-blue-500 transition-[width] duration-base ease-standard"
          style={{ width: `${safe}%` }}
        />
      </div>
    </div>
  )
}