(** README documentation rendering. *)

let contains text fragment =
  let text_length = String.length text in
  let fragment_length = String.length fragment in
  let rec loop index =
    if index > text_length - fragment_length then false
    else if String.sub text index fragment_length = fragment then true
    else loop (index + 1)
  in
  fragment_length <= text_length && loop 0

let count text fragment =
  let text_length = String.length text in
  let fragment_length = String.length fragment in
  let rec loop index acc =
    if index > text_length - fragment_length then acc
    else if String.sub text index fragment_length = fragment then
      loop (index + 1) (acc + 1)
    else loop (index + 1) acc
  in
  if fragment_length > text_length then 0 else loop 0 0

let render ~filename content =
  Prose.Render.render ~filename content |> Dream_html.to_string

let test_markdown_document () =
  let html =
    render ~filename:"README.md"
      "# Project\n\nIntroduction.\n\n## Installation\n\n- Download\n- Run\n"
  in
  Alcotest.(check bool)
    "documentation container" true
    (contains html "readme-document readme-markdown");
  Alcotest.(check bool) "h1 heading" true (contains html "<h1 id=\"project\"");
  Alcotest.(check bool)
    "heading fragment link" true
    (contains html "<a href=\"#project\" class=\"readme-heading-link\">Project");
  Alcotest.(check bool)
    "nested h2 heading" true
    (contains html "<h2 id=\"installation\"");
  Alcotest.(check bool)
    "no line-number anchors" false
    (contains html "line-anchor")

let test_org_document () =
  let html =
    render ~filename:"README.org"
      "#+TITLE: Org Project\n\
       #+AUTHOR: Ada Lovelace\n\
       #+DATE: 2026-08-01\n\n\
       * Overview\n\n\
       #+BEGIN_SRC ocaml\n\
       let answer = 42\n\
       #+END_SRC\n"
  in
  Alcotest.(check bool)
    "Org document container" true
    (contains html "readme-document readme-org");
  Alcotest.(check bool)
    "title heading" true
    (contains html "<h1 id=\"org-project\"");
  Alcotest.(check bool)
    "metadata definition list" true
    (contains html "<dl class=\"readme-org-metadata\"");
  Alcotest.(check bool) "author metadata" true (contains html "<dt>Author</dt>");
  Alcotest.(check bool) "Org heading" true (contains html "<h1 id=\"overview\"");
  Alcotest.(check bool)
    "highlighted source block" true
    (contains html "source.ocaml-keyword")

let test_readme_filename_detection () =
  Alcotest.(check bool)
    "case-insensitive README name" true
    (Prose.Render.is_readme_filename "ReadMe.ORG");
  Alcotest.(check bool)
    "ordinary file is not a README" false
    (Prose.Render.is_readme_filename "guide.md")

let test_markdown_toc () =
  let html =
    render ~filename:"README.md"
      "# Project\n\n## Getting Started\n\nText.\n\n## API\n\nMore text.\n"
  in
  Alcotest.(check bool)
    "TOC disclosure present" true
    (contains html "readme-toc");
  Alcotest.(check bool)
    "TOC contains summary" true
    (contains html "Table of Contents");
  Alcotest.(check bool)
    "TOC links to first heading" true
    (contains html "href=\"#getting-started\"");
  Alcotest.(check bool)
    "TOC links to second heading" true
    (contains html "href=\"#api\"");
  Alcotest.(check bool)
    "TOC has nested list for subheadings" true
    (count html "toc-list" >= 2)

let test_org_toc () =
  let html =
    render ~filename:"README.org"
      "#+TITLE: My Project\n\
       #+AUTHOR: Ada\n\n\
       * Overview\n\n\
       ** Installation\n\n\
       Text.\n\n\
       * Usage\n"
  in
  Alcotest.(check bool)
    "Org TOC disclosure present" true
    (contains html "readme-toc");
  Alcotest.(check bool)
    "Org TOC links to Overview" true
    (contains html "href=\"#overview\"");
  Alcotest.(check bool)
    "Org TOC links to Installation" true
    (contains html "href=\"#installation\"");
  Alcotest.(check bool)
    "Org TOC links to Usage" true
    (contains html "href=\"#usage\"");
  Alcotest.(check bool)
    "Org TOC has nested list for subheadings" true
    (count html "toc-list" >= 2);
  let find s sub =
    let slen = String.length s and sublen = String.length sub in
    let rec f i =
      if i > slen - sublen then -1
      else if String.sub s i sublen = sub then i
      else f (i + 1)
    in
    f 0
  in
  let toc_at = find html "readme-toc\"" in
  let meta_at = find html "readme-org-metadata" in
  Alcotest.(check bool)
    "Org metadata appears before TOC" true
    (toc_at >= 0 && meta_at >= 0 && meta_at < toc_at)

let test_no_toc_without_headings () =
  let html = render ~filename:"README.md" "Just a paragraph.\n" in
  Alcotest.(check bool)
    "no TOC when no headings" false
    (contains html "readme-toc")

let test_org_inline_verbatim () =
  let html =
    render ~filename:"README.org" "* Notes\n\nUse =verbatim= for emphasis.\n"
  in
  Alcotest.(check bool)
    "verbatim span" true
    (contains html "<span class=\"readme-verbatim\">verbatim</span>");
  Alcotest.(check bool) "surrounding text preserved" true (contains html "Use ")

let test_org_inline_code () =
  let html =
    render ~filename:"README.org" "* Notes\n\nCall ~List.map~ here.\n"
  in
  Alcotest.(check bool)
    "code element" true
    (contains html "<code class=\"readme-code\">List.map</code>")

let test_org_link_with_description () =
  let html =
    render ~filename:"README.org"
      "* Links\n\nSee [[https://example.com][Example Site]] for details.\n"
  in
  Alcotest.(check bool)
    "link href" true
    (contains html "href=\"https://example.com\"");
  Alcotest.(check bool) "link text" true (contains html ">Example Site</a>")

let test_org_link_bare () =
  let html =
    render ~filename:"README.org"
      "* Links\n\nVisit [[https://example.com]] today.\n"
  in
  Alcotest.(check bool)
    "bare link href" true
    (contains html "href=\"https://example.com\"");
  Alcotest.(check bool)
    "bare link text equals URL" true
    (contains html ">https://example.com</a>")

let test_org_unordered_list () =
  let html =
    render ~filename:"README.org"
      "* Tasks\n\n- First item\n- Second item\n- Third item\n"
  in
  Alcotest.(check bool)
    "unordered list" true
    (contains html "<ul class=\"readme-list\">");
  Alcotest.(check bool) "list item content" true (contains html "Second item")

let test_org_ordered_list () =
  let html =
    render ~filename:"README.org" "* Steps\n\n1. Download\n2. Install\n3. Run\n"
  in
  Alcotest.(check bool)
    "ordered list" true
    (contains html "<ol class=\"readme-list readme-ordered-list\">");
  Alcotest.(check bool) "ordered item content" true (contains html "Install")

let test_org_definition_list () =
  let html =
    render ~filename:"README.org"
      "* Glossary\n\n\
       - Term One :: The first definition\n\
       - Term Two :: The second definition\n"
  in
  Alcotest.(check bool)
    "definition list" true
    (contains html "<dl class=\"readme-definition-list\">");
  Alcotest.(check bool)
    "definition term" true
    (contains html "<dt>Term One</dt>");
  Alcotest.(check bool)
    "definition description" true
    (contains html "The first definition")

let test_org_inline_in_list () =
  let html =
    render ~filename:"README.org"
      "* Items\n\n- Use ~code~ in lists\n- And =verbatim= too\n"
  in
  Alcotest.(check bool)
    "code in list item" true
    (contains html "<code class=\"readme-code\">code</code>");
  Alcotest.(check bool)
    "verbatim in list item" true
    (contains html "<span class=\"readme-verbatim\">verbatim</span>")

let test_org_multiline_unordered () =
  let html =
    render ~filename:"README.org"
      "* Notes\n\n- First item\n  continues here\n- Second item\n"
  in
  Alcotest.(check bool)
    "continuation joined to first item" true
    (contains html "First item continues here");
  Alcotest.(check bool)
    "second item separate" true
    (contains html "Second item")

let test_org_multiline_ordered () =
  let html =
    render ~filename:"README.org"
      "* Steps\n\n1. Download the\n   archive first\n2. Install it\n"
  in
  Alcotest.(check bool)
    "ordered continuation joined" true
    (contains html "Download the archive first");
  Alcotest.(check bool)
    "second ordered item separate" true
    (contains html "Install it")

let test_org_multiline_definition () =
  let html =
    render ~filename:"README.org"
      "* Glossary\n\n\
       - Term :: First line\n\
      \   of the definition\n\
       - Other :: Short\n"
  in
  Alcotest.(check bool)
    "definition continuation joined" true
    (contains html "First line of the definition");
  Alcotest.(check bool)
    "second definition separate" true (contains html "Short")

let suite =
  ( "readme",
    [
      Alcotest.test_case "Markdown document" `Quick test_markdown_document;
      Alcotest.test_case "Org document" `Quick test_org_document;
      Alcotest.test_case "README filename detection" `Quick
        test_readme_filename_detection;
      Alcotest.test_case "Markdown TOC" `Quick test_markdown_toc;
      Alcotest.test_case "Org TOC" `Quick test_org_toc;
      Alcotest.test_case "No TOC without headings" `Quick
        test_no_toc_without_headings;
      Alcotest.test_case "Org verbatim inline" `Quick test_org_inline_verbatim;
      Alcotest.test_case "Org code inline" `Quick test_org_inline_code;
      Alcotest.test_case "Org link with description" `Quick
        test_org_link_with_description;
      Alcotest.test_case "Org bare link" `Quick test_org_link_bare;
      Alcotest.test_case "Org unordered list" `Quick test_org_unordered_list;
      Alcotest.test_case "Org ordered list" `Quick test_org_ordered_list;
      Alcotest.test_case "Org definition list" `Quick test_org_definition_list;
      Alcotest.test_case "Org inline in list items" `Quick
        test_org_inline_in_list;
      Alcotest.test_case "Org multi-line unordered items" `Quick
        test_org_multiline_unordered;
      Alcotest.test_case "Org multi-line ordered items" `Quick
        test_org_multiline_ordered;
      Alcotest.test_case "Org multi-line definition items" `Quick
        test_org_multiline_definition;
    ] )