import { marked } from 'marked';
import { escapeAttribute, highlightCode } from './highlight.js';

const modules = import.meta.glob('../../../../doc/manual/source/**/*.md', {
  query: '?raw',
  import: 'default',
  eager: true,
});

const documentEntries = Object.entries(modules).map(([path, content]) => {
  const relativePath = path
    .replace(/^\.\.\/\.\.\/\.\.\/\.\.\/doc\/manual\/source\//, '')
    .replace(/\.md$/, '');
  const pathParts = relativePath.split('/');
  const locale = pathParts[0] === 'jp' ? 'ja' : 'en';
  const localizedParts = locale === 'ja' ? pathParts.slice(1) : pathParts;
  const sourcePath = localizedParts.join('/');
  const base = localizedParts.slice(0, -1);
  const slug = sourcePath.replace(/\/index$/, '') || 'index';
  return { locale, slug, content, base };
});

const docsByLocale = Object.fromEntries(
  ['en', 'ja'].map((locale) => [
    locale,
    Object.fromEntries(
      documentEntries
        .filter((entry) => entry.locale === locale)
        .map(({ slug, content }) => [slug, content]),
    ),
  ]),
);

const docBasesByLocale = Object.fromEntries(
  ['en', 'ja'].map((locale) => [
    locale,
    Object.fromEntries(
      documentEntries
        .filter((entry) => entry.locale === locale)
        .map(({ slug, base }) => [slug, base]),
    ),
  ]),
);

const englishNav = [
  { title: 'Introduction', slug: 'introduction' },
  {
    title: 'Language Specification',
    slug: 'language',
    children: [
      { title: 'Syntax', slug: 'language/syntax' },
      { title: 'Grammar', slug: 'language/grammar' },
      {
        title: 'Value',
        slug: 'language/value',
        children: [
          { title: 'String', slug: 'language/value/string' },
          { title: 'Int', slug: 'language/value/int' },
          { title: 'Float', slug: 'language/value/float' },
          { title: 'Bool', slug: 'language/value/bool' },
        ],
      },
      {
        title: 'Expression',
        slug: 'language/expression',
        children: [
          { title: 'Literal', slug: 'language/expression/literal' },
          { title: 'Identifier', slug: 'language/expression/identifier' },
          { title: 'Path Reference', slug: 'language/expression/path-reference' },
          { title: 'Object', slug: 'language/expression/object' },
          { title: 'Array', slug: 'language/expression/array' },
          { title: 'Function', slug: 'language/expression/function' },
          { title: 'Function Call', slug: 'language/expression/function-call' },
          { title: 'Let', slug: 'language/expression/let' },
          { title: 'Match', slug: 'language/expression/match' },
          { title: 'Import', slug: 'language/expression/import' },
          { title: 'Composition', slug: 'language/expression/composition' },
          { title: 'Range Refinement', slug: 'language/expression/ascription' },
          { title: 'Default', slug: 'language/expression/default' },
          { title: 'Arithmetic', slug: 'language/expression/arithmetic' },
          { title: 'Logical and Comparison', slug: 'language/expression/logical-and-comparison' },
        ],
      },
      { title: 'Constraints and Defaults', slug: 'language/constraints-and-defaults' },
      { title: 'Operators', slug: 'language/operators' },
      { title: 'Functions', slug: 'language/functions' },
      { title: 'Modules and Imports', slug: 'language/modules-and-imports' },
      { title: 'Evaluation Semantics', slug: 'language/evaluation' },
      { title: 'Materialization and Errors', slug: 'language/materialization-and-errors' },
      { title: 'Naming', slug: 'language/naming' },
      { title: 'Examples', slug: 'language/examples' },
    ],
  },
  { title: 'Embedding', slug: 'embedding' },
  { title: 'Packages and Integrations', slug: 'components' },
];

const japaneseNav = [
  { title: 'はじめに', slug: 'introduction' },
  {
    title: '言語仕様',
    slug: 'language',
    children: [
      { title: '構文と字句', slug: 'language/syntax' },
      { title: '文法', slug: 'language/grammar' },
      {
        title: '値',
        slug: 'language/value',
        children: [
          { title: 'String', slug: 'language/value/string' },
          { title: 'Int', slug: 'language/value/int' },
          { title: 'Float', slug: 'language/value/float' },
          { title: 'Bool', slug: 'language/value/bool' },
        ],
      },
      {
        title: '式',
        slug: 'language/expression',
        children: [
          { title: 'リテラル', slug: 'language/expression/literal' },
          { title: '識別子', slug: 'language/expression/identifier' },
          { title: 'パス参照', slug: 'language/expression/path-reference' },
          { title: 'オブジェクト', slug: 'language/expression/object' },
          { title: '配列', slug: 'language/expression/array' },
          { title: '関数', slug: 'language/expression/function' },
          { title: '関数呼び出し', slug: 'language/expression/function-call' },
          { title: 'let', slug: 'language/expression/let' },
          { title: 'match', slug: 'language/expression/match' },
          { title: 'import', slug: 'language/expression/import' },
          { title: '合成', slug: 'language/expression/composition' },
          { title: '範囲の絞り込み', slug: 'language/expression/ascription' },
          { title: 'default', slug: 'language/expression/default' },
          { title: '算術式', slug: 'language/expression/arithmetic' },
          { title: '論理式と比較式', slug: 'language/expression/logical-and-comparison' },
        ],
      },
      { title: '制約とdefault', slug: 'language/constraints-and-defaults' },
      { title: '演算子', slug: 'language/operators' },
      { title: '関数', slug: 'language/functions' },
      { title: 'モジュールとimport', slug: 'language/modules-and-imports' },
      { title: '遅延評価', slug: 'language/evaluation' },
      { title: '具体化とエラー', slug: 'language/materialization-and-errors' },
      { title: '命名規約', slug: 'language/naming' },
      { title: '例', slug: 'language/examples' },
    ],
  },
  { title: '組み込み', slug: 'embedding' },
  { title: 'パッケージと統合', slug: 'components' },
];

const navByLocale = {
  en: englishNav,
  ja: japaneseNav,
};

const renderer = new marked.Renderer();

renderer.code = (code, language = '') => {
  const normalizedLanguage = language.split(/\s+/)[0] ?? '';
  const className = normalizedLanguage ? ` class="language-${escapeAttribute(normalizedLanguage)}"` : '';
  return `<pre class="code-block"><code${className}>${highlightCode(code, normalizedLanguage)}</code></pre>`;
};

renderer.codespan = (code) => `<code>${code}</code>`;

marked.setOptions({ gfm: true, renderer });

export function getNav(locale = 'en') {
  return navByLocale[locale] ?? englishNav;
}

export function allDocSlugs(locale = 'en') {
  return Object.keys(docsByLocale[locale] ?? {}).filter((slug) => slug !== 'index');
}

function flattenNav(items) {
  return items.flatMap((item) => [item.slug, ...(item.children ? flattenNav(item.children) : [])]);
}

export function orderedDocSlugs(locale = 'en', { includeIndex = false } = {}) {
  const localizedDocs = docsByLocale[locale] ?? docsByLocale.en;
  const slugs = flattenNav(getNav(locale)).filter((slug) => localizedDocs[slug]);
  return includeIndex ? ['index', ...slugs] : slugs;
}

function findDocTitle(slug, items) {
  for (const item of items) {
    if (item.slug === slug) return item.title;
    if (item.children) {
      const childTitle = findDocTitle(slug, item.children);
      if (childTitle) return childTitle;
    }
  }
  return undefined;
}

export function docTitle(slug, locale = 'en') {
  if (slug === 'index') return locale === 'ja' ? 'Decodalマニュアル' : 'Decodal Manual';
  return findDocTitle(slug, getNav(locale)) ?? slug;
}

function getSource(slug, locale) {
  const localizedDocs = docsByLocale[locale] ?? docsByLocale.en;
  return localizedDocs[slug] ?? localizedDocs.index ?? '# Not found\n';
}

function stripInlineMarkdown(value) {
  return value
    .replace(/!\[([^\]]*)\]\([^)]*\)/g, '$1')
    .replace(/\[([^\]]+)\]\([^)]*\)/g, '$1')
    .replace(/[`*_~]/g, '')
    .replace(/<[^>]+>/g, '')
    .replace(/\s+/g, ' ')
    .trim();
}

export function docDescription(slug, locale = 'en') {
  const blocks = getSource(slug, locale)
    .replace(/```[\s\S]*?```/g, '')
    .split(/\n\s*\n/)
    .map((block) => block.trim())
    .filter((block) => block && !block.startsWith('#') && !/^[-*]\s/.test(block));
  const description = stripInlineMarkdown(blocks[0] ?? '');
  if (description.length <= 180) return description;
  const shortened = description.slice(0, 177).replace(/\s+\S*$/, '').trimEnd();
  return `${shortened || description.slice(0, 177)}…`;
}

export function sourceMarkdown(slug, locale = 'en') {
  return getSource(slug, locale).replace(/\]\(([^)\s]+)\)/g, (all, destination) => {
    const [href, hash = ''] = destination.split('#', 2);
    if (!href.endsWith('.md')) return all;
    const target = normalizeDocLink(locale, slug, href.slice(0, -3));
    const pathname = target === 'index'
      ? `/docs/${locale}.md`
      : `/docs/${locale}/${target}.md`;
    return `](${pathname}${hash ? `#${hash}` : ''})`;
  });
}

export function renderMarkdown(slug, locale = 'en') {
  const html = marked.parse(getSource(slug, locale));
  return html.replace(/href="([^"#][^"]*)\.md(#[^"]*)?"/g, (_all, href, hash = '') => {
    const target = normalizeDocLink(locale, slug, href);
    const pathname = target === 'index' ? `/docs/${locale}/` : `/docs/${locale}/${target}/`;
    return `href="${pathname}${hash}"`;
  });
}

function normalizeDocLink(locale, currentSlug, href) {
  const base = docBasesByLocale[locale]?.[currentSlug] ?? [];
  const parts = [...base, ...href.split('/')];
  const out = [];
  for (const part of parts) {
    if (!part || part === '.') continue;
    if (part === '..') out.pop();
    else out.push(part);
  }
  if (out[out.length - 1] === 'index') out.pop();
  return out.join('/') || 'index';
}