import type { ArticlesBlock, BannerBlock, BannerStyle, Breadcrumb, ContentBlock, FaqBlock, LanguageAlternative, Media, MediaBlock, MediaContentBlock, NavigationLink, NavigationLinkVariant, PageBlock, PageDocument, PageHero, PageRequest, PageResolution, PageTeaser, PageTeaserList, RichText, SitemapEntry, SiteMenu, SiteSettings, UnknownBlock } from '../types';

const LINK_VARIANTS = new Set<NavigationLinkVariant>([
  'primary',
  'secondary',
  'outline',
  'ghost',
  'inline'
]);

const HERO_IMPACTS = new Set(['none', 'low', 'middle', 'high']);

const BANNER_STYLES = new Set<BannerStyle>(['info', 'success', 'warning', 'error']);

export function isRecord(value: unknown): value is Record<string, unknown> {
  return typeof value === 'object' && value !== null && !Array.isArray(value);
}

function asString(value: unknown, fallback = ''): string {
  return typeof value === 'string' ? value : fallback;
}

function asOptionalString(value: unknown): string | undefined {
  return typeof value === 'string' && value.length > 0 ? value : undefined;
}

function asOptionalNumber(value: unknown): number | undefined {
  return typeof value === 'number' && Number.isFinite(value) ? value : undefined;
}

function normalizePath(value: string): string {
  return value.split('/').filter(Boolean).join('/');
}

function normalizeRichText(value: unknown): RichText {
  if (isRecord(value)) {
    return { content: asString(value['content']) };
  }

  return { content: asString(value) };
}

function normalizeMedia(value: unknown): Media | undefined {
  if (!isRecord(value)) {
    return undefined;
  }

  const url = asString(value['url']);
  if (!url) {
    return undefined;
  }

  const media: Media = {
    url,
    alt: asString(value['alt'])
  };
  const width = asOptionalNumber(value['width']);
  const height = asOptionalNumber(value['height']);
  const mimeType = asOptionalString(value['mimeType']);

  if (width !== undefined) media.width = width;
  if (height !== undefined) media.height = height;
  if (mimeType !== undefined) media.mimeType = mimeType;

  return media;
}

function normalizeNavigationLink(value: unknown): NavigationLink | null {
  if (!isRecord(value)) {
    return null;
  }

  const label = asString(value['label']);
  if (!label) {
    return null;
  }

  const rawVariant = asString(value['variant']);
  const variant = LINK_VARIANTS.has(rawVariant as NavigationLinkVariant)
    ? (rawVariant as NavigationLinkVariant)
    : 'ghost';
  const rawLinkType = asString(value['linkType']);
  const linkType = rawLinkType === 'internal' ? 'internal' : 'external';
  const rawPageId = value['pageId'];
  const link: NavigationLink = {
    linkType,
    pageId: typeof rawPageId === 'number' || typeof rawPageId === 'string' ? String(rawPageId) : '',
    externalUrl: asString(value['externalUrl']),
    openInNewTab: value['openInNewTab'] === true,
    label,
    variant
  };
  const href = asOptionalString(value['href'] ?? value['url'] ?? value['path']);

  if (href !== undefined) link.href = href;

  return link;
}

function normalizeNavigationLinks(value: unknown): NavigationLink[] {
  if (!Array.isArray(value)) {
    return [];
  }

  return value
    .map((item) => normalizeNavigationLink(item))
    .filter((item): item is NavigationLink => item !== null);
}

function normalizeBreadcrumbs(value: unknown): Breadcrumb[] {
  if (!Array.isArray(value)) {
    return [];
  }

  return value.filter(isRecord).flatMap((item) => {
    const label = asString(item['label']);
    const href = asString(item['href']);

    return label ? [{ label, href }] : [];
  });
}

function normalizeHero(value: unknown): PageHero | undefined {
  if (!isRecord(value)) {
    return undefined;
  }

  const rawImpact = asString(value['type']);
  const type = HERO_IMPACTS.has(rawImpact) ? (rawImpact as PageHero['type']) : 'middle';
  const hero: PageHero = {
    type,
    ctaItems: normalizeNavigationLinks(value['ctaItems'])
  };
  const title = asOptionalString(value['title']);
  const subtitle = asOptionalString(value['subtitle']);
  const content = normalizeRichText(value['content']);
  const media = normalizeMedia(value['media']);

  if (title !== undefined) hero.title = title;
  if (subtitle !== undefined) hero.subtitle = subtitle;
  if (content.content) hero.content = content;
  if (media !== undefined) hero.media = media;

  return hero;
}

function unwrapBlock(value: Record<string, unknown>): Record<string, unknown> {
  const data = value['data'];
  if (!isRecord(data)) {
    return value;
  }

  return {
    ...data,
    id: value['id'] ?? data['id'],
    type: value['type'] ?? data['type']
  };
}

function normalizeBlock(value: unknown, index: number): PageBlock | null {
  if (!isRecord(value)) {
    return null;
  }

  const block = unwrapBlock(value);
  const type = asString(block['type']);
  if (!type) {
    return null;
  }

  const id = String(block['id'] ?? `${type}-${index + 1}`);

  if (type === 'content') {
    const columns = Array.isArray(block['columns'])
      ? block['columns'].filter(isRecord).map((column) => ({
          content: normalizeRichText(column['content']),
          ctaItems: normalizeNavigationLinks(column['ctaItems'])
        }))
      : [];

    return {
      id,
      type,
      title: asString(block['title']),
      subtitle: asString(block['subtitle']),
      columns
    } satisfies ContentBlock;
  }

  if (type === 'faq') {
    const items = Array.isArray(block['items'])
      ? block['items'].filter(isRecord).map((item) => ({
          question: asString(item['question']),
          answer: asString(item['answer'])
        }))
      : [];

    return {
      id,
      type,
      title: asString(block['title']),
      subtitle: asString(block['subtitle']),
      items
    } satisfies FaqBlock;
  }

  if (type === 'media-content') {
    return {
      id,
      type,
      title: asString(block['title']),
      mediaPosition: block['mediaPosition'] === 'right' ? 'right' : 'left',
      media: normalizeMedia(block['media']),
      content: normalizeRichText(block['content']),
      ctaItems: normalizeNavigationLinks(block['ctaItems'])
    } satisfies MediaContentBlock;
  }

  if (type === 'articles') {
    const items = Array.isArray(block['items'])
      ? block['items'].filter(isRecord).map((item) => ({
          title: asString(item['title']),
          content: normalizeRichText(item['content'])
        }))
      : [];
    const cta = normalizeNavigationLink(block['cta']);
    const articlesBlock: ArticlesBlock = {
      id,
      type,
      title: asString(block['title']),
      subtitle: normalizeRichText(block['subtitle']),
      items
    };

    if (cta !== null) articlesBlock.cta = cta;

    return articlesBlock;
  }

  if (type === 'banner') {
    const rawStyle = asString(block['style']);

    return {
      id,
      type,
      style: BANNER_STYLES.has(rawStyle as BannerStyle) ? (rawStyle as BannerStyle) : 'info',
      content: normalizeRichText(block['content']),
      ctaItems: normalizeNavigationLinks(block['ctaItems'])
    } satisfies BannerBlock;
  }

  if (type === 'media') {
    return {
      id,
      type,
      media: normalizeMedia(block['media'])
    } satisfies MediaBlock;
  }

  return {
    id,
    type,
    data: block
  } satisfies UnknownBlock;
}

function normalizeBlocks(value: unknown): PageBlock[] {
  if (!Array.isArray(value)) {
    return [];
  }

  return value
    .map((block, index) => normalizeBlock(block, index))
    .filter((block): block is PageBlock => block !== null);
}

function normalizeLayout(value: unknown, fallbackValue: unknown): string {
  if (typeof value === 'string') {
    return value;
  }

  if (isRecord(value)) {
    return asString(value['type'], 'landing');
  }

  return asString(fallbackValue, 'landing');
}

export function normalizePage(value: unknown, request: PageRequest): PageDocument | null {
  if (!isRecord(value)) {
    return null;
  }

  const hasPageIdentity =
    value['id'] !== undefined ||
    typeof value['path'] === 'string' ||
    typeof value['title'] === 'string';
  if (!hasPageIdentity) {
    return null;
  }

  const path = normalizePath(asString(value['path'], request.path));
  const finalPathSegment = path.split('/').at(-1) ?? '';
  const locale = asString(value['locale'], request.locale);
  const hero = normalizeHero(value['hero']);
  const seoValue = isRecord(value['seo']) ? value['seo'] : {};
  const title = asString(value['title'], hero?.title ?? finalPathSegment);
  const page: PageDocument = {
    id: String(value['id'] ?? `${locale}:${path || 'index'}`),
    status: asString(value['status'], 'published'),
    locale,
    path,
    groupKey: asString(value['groupKey'], finalPathSegment),
    layout: normalizeLayout(value['layout'], value['pageType']),
    title,
    seo: {
      title: asString(seoValue['title'] ?? value['seoTitle'], title),
      description: asString(seoValue['description'] ?? value['seoDescription'])
    },
    breadcrumbs: normalizeBreadcrumbs(value['breadcrumbs']),
    blocks: normalizeBlocks(value['blocks'] ?? value['components']),
    publishedAt: asOptionalString(value['publishedAt']) ?? null,
    updatedAt: asOptionalString(value['updatedAt']) ?? null
  };

  if (hero !== undefined) page.hero = hero;

  return page;
}

function normalizeMenus(value: unknown): SiteMenu[] {
  if (!Array.isArray(value)) {
    return [];
  }

  return value.filter(isRecord).map((menu) => ({
    title: asString(menu['title']).trim(),
    items: normalizeNavigationLinks(menu['items'])
  }));
}

export function createEmptySiteSettings(locale: string): SiteSettings {
  return {
    locale,
    header: { menus: [], ctaItems: [] },
    footer: { copyright: '', menus: [] },
    legal: { privacyPath: '', termsPath: '' }
  };
}

export function normalizeSiteSettings(value: unknown, locale: string): SiteSettings | null {
  if (!isRecord(value)) {
    return null;
  }

  const header = isRecord(value['header']) ? value['header'] : {};
  const footer = isRecord(value['footer']) ? value['footer'] : {};
  const legal = isRecord(value['legal']) ? value['legal'] : {};

  return {
    locale: asString(value['locale'], locale),
    header: {
      menus: normalizeMenus(header['menus']),
      ctaItems: normalizeNavigationLinks(header['ctaItems'])
    },
    footer: {
      copyright: asString(footer['copyright']),
      menus: normalizeMenus(footer['menus'])
    },
    legal: {
      privacyPath: asString(legal['privacyPath']),
      termsPath: asString(legal['termsPath'])
    }
  };
}

function normalizeLanguageAlternatives(value: unknown): LanguageAlternative[] {
  if (!Array.isArray(value)) {
    return [];
  }

  return value.filter(isRecord).flatMap((item) => {
    const locale = asString(item['locale']);
    const path = normalizePath(asString(item['path']));

    return locale ? [{ locale, path }] : [];
  });
}

export function normalizePageResolution(
  value: unknown,
  request: PageRequest
): PageResolution | null {
  if (!isRecord(value)) {
    return null;
  }

  const root = isRecord(value['data']) ? value['data'] : value;
  const wrappedPage = isRecord(root['page']) ? root['page'] : null;
  const rawPage = wrappedPage
    ? {
        ...wrappedPage,
        blocks: root['components'] ?? wrappedPage['blocks'],
        hero: wrappedPage['hero'] ?? root['hero'],
        breadcrumbs: root['breadcrumbs'] ?? wrappedPage['breadcrumbs']
      }
    : root;
  const page = normalizePage(rawPage, request);

  if (!page) {
    return null;
  }

  const resolution: PageResolution = {
    page,
    languageAlternatives: normalizeLanguageAlternatives(root['languageAlternatives'])
  };
  const settings = normalizeSiteSettings(root['settings'], request.locale);

  if (settings) resolution.settings = settings;

  return resolution;
}

export function normalizeSitemapEntries(payload: unknown): SitemapEntry[] {
  if (!isRecord(payload) || !Array.isArray(payload['items'])) {
    return [];
  }

  return payload['items'].filter(isRecord).flatMap((item) => {
    const locale = asString(item['locale']);

    if (!locale) {
      return [];
    }

    return [
      {
        locale,
        path: normalizePath(asString(item['path'])),
        groupKey: asString(item['groupKey']),
        pageType: asString(item['pageType']),
        publishedAt: asOptionalString(item['publishedAt']) ?? null,
        updatedAt: asOptionalString(item['updatedAt']) ?? null
      }
    ];
  });
}

export function sitemapLastPage(payload: unknown): number {
  const pagination =
    isRecord(payload) && isRecord(payload['pagination']) ? payload['pagination'] : {};
  const lastPage = pagination['lastPage'];

  return typeof lastPage === 'number' && Number.isInteger(lastPage) && lastPage > 0 ? lastPage : 1;
}

export function normalizeRoutePath(path: string): string {
  return normalizePath(path);
}

export function normalizePageTeaserList(payload: unknown): PageTeaserList {
  const items = normalizePageTeasers(payload);
  const rawPagination =
    isRecord(payload) && isRecord(payload['pagination']) ? payload['pagination'] : {};

  const asPositiveInt = (value: unknown, fallback: number): number => {
    return typeof value === 'number' && Number.isInteger(value) && value > 0 ? value : fallback;
  };

  return {
    items,
    pagination: {
      page: asPositiveInt(rawPagination['page'], 1),
      perPage: asPositiveInt(rawPagination['perPage'], Math.max(items.length, 1)),
      total: asPositiveInt(rawPagination['total'], items.length),
      lastPage: asPositiveInt(rawPagination['lastPage'], 1)
    }
  };
}

export function normalizePageTeasers(payload: unknown): PageTeaser[] {
  if (!isRecord(payload) || !Array.isArray(payload['items'])) {
    return [];
  }

  return payload['items'].filter(isRecord).flatMap((item) => {
    const title = asString(item['title']);
    const path = normalizePath(asString(item['path']));

    if (!title || !path) {
      return [];
    }

    const teaser: PageTeaser = {
      id: String(item['id'] ?? path),
      path,
      title,
      description: asString(item['description']),
      publishedAt: asOptionalString(item['publishedAt']) ?? null
    };
    const media = normalizeMedia(item['media']);

    if (media !== undefined) teaser.media = media;

    return [teaser];
  });
}