(* HTML5 spec constants *)

(* Use Astring for string operations *)
let lowercase = Astring.String.Ascii.lowercase

(* Helper to create a hashtable set from a list for O(1) membership *)
let make_set elements =
  let tbl = Hashtbl.create (List.length elements) in
  List.iter (fun e -> Hashtbl.add tbl e ()) elements;
  tbl

(* Void elements - no end tag allowed *)
let void_elements = [
  "area"; "base"; "br"; "col"; "embed"; "hr"; "img"; "input";
  "link"; "meta"; "source"; "track"; "wbr"
]
let void_elements_tbl = make_set void_elements

(* Raw text elements - content is raw text *)
let raw_text_elements = ["script"; "style"]

(* Escapable raw text elements *)
let escapable_raw_text_elements = ["textarea"; "title"]

(* Formatting elements for adoption agency *)
let formatting_elements = [
  "a"; "b"; "big"; "code"; "em"; "font"; "i"; "nobr"; "s"; "small";
  "strike"; "strong"; "tt"; "u"
]
let formatting_elements_tbl = make_set formatting_elements

(* Special elements *)
let special_elements = [
  "address"; "applet"; "area"; "article"; "aside"; "base"; "basefont";
  "bgsound"; "blockquote"; "body"; "br"; "button"; "caption"; "center";
  "col"; "colgroup"; "dd"; "details"; "dir"; "div"; "dl"; "dt"; "embed";
  "fieldset"; "figcaption"; "figure"; "footer"; "form"; "frame"; "frameset";
  "h1"; "h2"; "h3"; "h4"; "h5"; "h6"; "head"; "header"; "hgroup"; "hr";
  "html"; "iframe"; "img"; "input"; "keygen"; "li"; "link"; "listing";
  "main"; "marquee"; "menu"; "meta"; "nav"; "noembed"; "noframes";
  "noscript"; "object"; "ol"; "p"; "param"; "plaintext"; "pre"; "script";
  "search"; "section"; "select"; "source"; "style"; "summary"; "table";
  "tbody"; "td"; "template"; "textarea"; "tfoot"; "th"; "thead"; "title";
  "tr"; "track"; "ul"; "wbr"; "xmp"
]
let special_elements_tbl = make_set special_elements

(* Heading elements *)
let heading_elements = ["h1"; "h2"; "h3"; "h4"; "h5"; "h6"]
let heading_elements_tbl = make_set heading_elements

(* Implied end tag elements *)
let implied_end_tags = [
  "dd"; "dt"; "li"; "optgroup"; "option"; "p"; "rb"; "rp"; "rt"; "rtc"
]
let implied_end_tags_tbl = make_set implied_end_tags

(* Thoroughly implied end tags *)
let thoroughly_implied_end_tags = [
  "caption"; "colgroup"; "dd"; "dt"; "li"; "optgroup"; "option"; "p";
  "rb"; "rp"; "rt"; "rtc"; "tbody"; "td"; "tfoot"; "th"; "thead"; "tr"
]
let thoroughly_implied_end_tags_tbl = make_set thoroughly_implied_end_tags

(* Scope elements for various scope checks *)
let default_scope = [
  "applet"; "caption"; "html"; "table"; "td"; "th"; "marquee"; "object"; "template"
]

let list_item_scope = default_scope @ ["ol"; "ul"]

let button_scope = default_scope @ ["button"]

let table_scope = ["html"; "table"; "template"]

let select_scope_exclude = ["optgroup"; "option"]
let select_scope_exclude_tbl = make_set select_scope_exclude

(* MathML text integration points *)
let mathml_text_integration = ["mi"; "mo"; "mn"; "ms"; "mtext"]
let mathml_text_integration_tbl = make_set mathml_text_integration

(* MathML attribute adjustments - O(1) hashtable lookup *)
let mathml_attr_adjustments_tbl =
  let adjustments = [("definitionurl", "definitionURL")] in
  let tbl = Hashtbl.create 4 in
  List.iter (fun (k, v) -> Hashtbl.add tbl k v) adjustments;
  tbl

let adjust_mathml_attrs attrs =
  List.map (fun (k, v) ->
    match Hashtbl.find_opt mathml_attr_adjustments_tbl (lowercase k) with
    | Some adjusted_k -> (adjusted_k, v)
    | None -> (k, v)
  ) attrs

(* SVG HTML integration points *)
let svg_html_integration = ["foreignObject"; "desc"; "title"]
let svg_html_integration_tbl = make_set (List.map lowercase svg_html_integration)

(* Helper to create hashtable from association list for O(1) lookup *)
let make_assoc_tbl pairs =
  let tbl = Hashtbl.create (List.length pairs) in
  List.iter (fun (k, v) -> Hashtbl.add tbl k v) pairs;
  tbl

(* SVG tag name adjustments *)
let svg_tag_adjustments = [
  ("altglyph", "altGlyph");
  ("altglyphdef", "altGlyphDef");
  ("altglyphitem", "altGlyphItem");
  ("animatecolor", "animateColor");
  ("animatemotion", "animateMotion");
  ("animatetransform", "animateTransform");
  ("clippath", "clipPath");
  ("feblend", "feBlend");
  ("fecolormatrix", "feColorMatrix");
  ("fecomponenttransfer", "feComponentTransfer");
  ("fecomposite", "feComposite");
  ("feconvolvematrix", "feConvolveMatrix");
  ("fediffuselighting", "feDiffuseLighting");
  ("fedisplacementmap", "feDisplacementMap");
  ("fedistantlight", "feDistantLight");
  ("fedropshadow", "feDropShadow");
  ("feflood", "feFlood");
  ("fefunca", "feFuncA");
  ("fefuncb", "feFuncB");
  ("fefuncg", "feFuncG");
  ("fefuncr", "feFuncR");
  ("fegaussianblur", "feGaussianBlur");
  ("feimage", "feImage");
  ("femerge", "feMerge");
  ("femergenode", "feMergeNode");
  ("femorphology", "feMorphology");
  ("feoffset", "feOffset");
  ("fepointlight", "fePointLight");
  ("fespecularlighting", "feSpecularLighting");
  ("fespotlight", "feSpotLight");
  ("fetile", "feTile");
  ("feturbulence", "feTurbulence");
  ("foreignobject", "foreignObject");
  ("glyphref", "glyphRef");
  ("lineargradient", "linearGradient");
  ("radialgradient", "radialGradient");
  ("textpath", "textPath");
]
let svg_tag_adjustments_tbl = make_assoc_tbl svg_tag_adjustments

(* SVG attribute adjustments *)
let svg_attr_adjustments = [
  ("attributename", "attributeName");
  ("attributetype", "attributeType");
  ("basefrequency", "baseFrequency");
  ("baseprofile", "baseProfile");
  ("calcmode", "calcMode");
  ("clippathunits", "clipPathUnits");
  ("diffuseconstant", "diffuseConstant");
  ("edgemode", "edgeMode");
  ("filterunits", "filterUnits");
  ("glyphref", "glyphRef");
  ("gradienttransform", "gradientTransform");
  ("gradientunits", "gradientUnits");
  ("kernelmatrix", "kernelMatrix");
  ("kernelunitlength", "kernelUnitLength");
  ("keypoints", "keyPoints");
  ("keysplines", "keySplines");
  ("keytimes", "keyTimes");
  ("lengthadjust", "lengthAdjust");
  ("limitingconeangle", "limitingConeAngle");
  ("markerheight", "markerHeight");
  ("markerunits", "markerUnits");
  ("markerwidth", "markerWidth");
  ("maskcontentunits", "maskContentUnits");
  ("maskunits", "maskUnits");
  ("numoctaves", "numOctaves");
  ("pathlength", "pathLength");
  ("patterncontentunits", "patternContentUnits");
  ("patterntransform", "patternTransform");
  ("patternunits", "patternUnits");
  ("pointsatx", "pointsAtX");
  ("pointsaty", "pointsAtY");
  ("pointsatz", "pointsAtZ");
  ("preservealpha", "preserveAlpha");
  ("preserveaspectratio", "preserveAspectRatio");
  ("primitiveunits", "primitiveUnits");
  ("refx", "refX");
  ("refy", "refY");
  ("repeatcount", "repeatCount");
  ("repeatdur", "repeatDur");
  ("requiredextensions", "requiredExtensions");
  ("requiredfeatures", "requiredFeatures");
  ("specularconstant", "specularConstant");
  ("specularexponent", "specularExponent");
  ("spreadmethod", "spreadMethod");
  ("startoffset", "startOffset");
  ("stddeviation", "stdDeviation");
  ("stitchtiles", "stitchTiles");
  ("surfacescale", "surfaceScale");
  ("systemlanguage", "systemLanguage");
  ("tablevalues", "tableValues");
  ("targetx", "targetX");
  ("targety", "targetY");
  ("textlength", "textLength");
  ("viewbox", "viewBox");
  ("viewtarget", "viewTarget");
  ("xchannelselector", "xChannelSelector");
  ("ychannelselector", "yChannelSelector");
  ("zoomandpan", "zoomAndPan");
]
let svg_attr_adjustments_tbl = make_assoc_tbl svg_attr_adjustments

(* Foreign attribute adjustments *)
let foreign_attr_adjustments = [
  ("xlink:actuate", ("xlink", "actuate", "http://www.w3.org/1999/xlink"));
  ("xlink:arcrole", ("xlink", "arcrole", "http://www.w3.org/1999/xlink"));
  ("xlink:href", ("xlink", "href", "http://www.w3.org/1999/xlink"));
  ("xlink:role", ("xlink", "role", "http://www.w3.org/1999/xlink"));
  ("xlink:show", ("xlink", "show", "http://www.w3.org/1999/xlink"));
  ("xlink:title", ("xlink", "title", "http://www.w3.org/1999/xlink"));
  ("xlink:type", ("xlink", "type", "http://www.w3.org/1999/xlink"));
  ("xml:lang", ("xml", "lang", "http://www.w3.org/XML/1998/namespace"));
  ("xml:space", ("xml", "space", "http://www.w3.org/XML/1998/namespace"));
  ("xmlns", ("", "xmlns", "http://www.w3.org/2000/xmlns/"));
  ("xmlns:xlink", ("xmlns", "xlink", "http://www.w3.org/2000/xmlns/"));
]
let foreign_attr_adjustments_tbl = make_assoc_tbl foreign_attr_adjustments

(* Quirks mode detection *)
let quirky_public_matches = [
  "-//w3o//dtd w3 html strict 3.0//en//";
  "-/w3c/dtd html 4.0 transitional/en";
  "html"
]

let quirky_public_prefixes = [
  "+//silmaril//dtd html pro v0r11 19970101//";
  "-//as//dtd html 3.0 aswedit + extensions//";
  "-//advasoft ltd//dtd html 3.0 aswedit + extensions//";
  "-//ietf//dtd html 2.0 level 1//";
  "-//ietf//dtd html 2.0 level 2//";
  "-//ietf//dtd html 2.0 strict level 1//";
  "-//ietf//dtd html 2.0 strict level 2//";
  "-//ietf//dtd html 2.0 strict//";
  "-//ietf//dtd html 2.0//";
  "-//ietf//dtd html 2.1e//";
  "-//ietf//dtd html 3.0//";
  "-//ietf//dtd html 3.2 final//";
  "-//ietf//dtd html 3.2//";
  "-//ietf//dtd html 3//";
  "-//ietf//dtd html level 0//";
  "-//ietf//dtd html level 1//";
  "-//ietf//dtd html level 2//";
  "-//ietf//dtd html level 3//";
  "-//ietf//dtd html strict level 0//";
  "-//ietf//dtd html strict level 1//";
  "-//ietf//dtd html strict level 2//";
  "-//ietf//dtd html strict level 3//";
  "-//ietf//dtd html strict//";
  "-//ietf//dtd html//";
  "-//metrius//dtd metrius presentational//";
  "-//microsoft//dtd internet explorer 2.0 html strict//";
  "-//microsoft//dtd internet explorer 2.0 html//";
  "-//microsoft//dtd internet explorer 2.0 tables//";
  "-//microsoft//dtd internet explorer 3.0 html strict//";
  "-//microsoft//dtd internet explorer 3.0 html//";
  "-//microsoft//dtd internet explorer 3.0 tables//";
  "-//netscape comm. corp.//dtd html//";
  "-//netscape comm. corp.//dtd strict html//";
  "-//o'reilly and associates//dtd html 2.0//";
  "-//o'reilly and associates//dtd html extended 1.0//";
  "-//o'reilly and associates//dtd html extended relaxed 1.0//";
  "-//sq//dtd html 2.0 hotmetal + extensions//";
  "-//softquad software//dtd hotmetal pro 6.0::19990601::extensions to html 4.0//";
  "-//softquad//dtd hotmetal pro 4.0::19971010::extensions to html 4.0//";
  "-//spyglass//dtd html 2.0 extended//";
  "-//sun microsystems corp.//dtd hotjava html//";
  "-//sun microsystems corp.//dtd hotjava strict html//";
  "-//w3c//dtd html 3 1995-03-24//";
  "-//w3c//dtd html 3.2 draft//";
  "-//w3c//dtd html 3.2 final//";
  "-//w3c//dtd html 3.2//";
  "-//w3c//dtd html 3.2s draft//";
  "-//w3c//dtd html 4.0 frameset//";
  "-//w3c//dtd html 4.0 transitional//";
  "-//w3c//dtd html experimental 19960712//";
  "-//w3c//dtd html experimental 970421//";
  "-//w3c//dtd w3 html//";
  "-//w3o//dtd w3 html 3.0//";
  "-//webtechs//dtd mozilla html 2.0//";
  "-//webtechs//dtd mozilla html//";
]

let limited_quirky_public_prefixes = [
  "-//w3c//dtd xhtml 1.0 frameset//";
  "-//w3c//dtd xhtml 1.0 transitional//";
]

let html4_public_prefixes = [
  "-//w3c//dtd html 4.01 frameset//";
  "-//w3c//dtd html 4.01 transitional//";
]

let quirky_system_matches = [
  "http://www.ibm.com/data/dtd/v11/ibmxhtml1-transitional.dtd"
]

(* Table-related element sets for tree builder O(1) lookups *)
let table_section_elements = ["tbody"; "thead"; "tfoot"]
let table_section_elements_tbl = make_set table_section_elements

let table_cell_elements = ["td"; "th"]
let table_cell_elements_tbl = make_set table_cell_elements

let foster_parenting_elements = ["table"; "tbody"; "tfoot"; "thead"; "tr"]
let foster_parenting_elements_tbl = make_set foster_parenting_elements

(* Helper functions - O(1) hashtable lookups *)
let is_void_element name = Hashtbl.mem void_elements_tbl name
let is_formatting_element name = Hashtbl.mem formatting_elements_tbl name
let is_special_element name = Hashtbl.mem special_elements_tbl name
let is_heading_element name = Hashtbl.mem heading_elements_tbl name
let is_implied_end_tag name = Hashtbl.mem implied_end_tags_tbl name
let is_thoroughly_implied_end_tag name = Hashtbl.mem thoroughly_implied_end_tags_tbl name
let is_mathml_text_integration name = Hashtbl.mem mathml_text_integration_tbl name
let is_svg_html_integration name = Hashtbl.mem svg_html_integration_tbl (lowercase name)
let is_select_scope_exclude name = Hashtbl.mem select_scope_exclude_tbl name
let is_table_section_element name = Hashtbl.mem table_section_elements_tbl name
let is_table_cell_element name = Hashtbl.mem table_cell_elements_tbl name
let is_foster_parenting_element name = Hashtbl.mem foster_parenting_elements_tbl name

(* Backwards compatibility aliases *)
let is_void = List.mem
let is_formatting = List.mem
let is_special name = List.mem name special_elements
let is_heading = List.mem

let adjust_svg_tag_name name =
  match Hashtbl.find_opt svg_tag_adjustments_tbl (lowercase name) with
  | Some adjusted -> adjusted
  | None -> name

let adjust_svg_attrs attrs =
  List.map (fun (name, value) ->
    let adjusted_name =
      match Hashtbl.find_opt svg_attr_adjustments_tbl (lowercase name) with
      | Some n -> n
      | None -> name
    in
    (adjusted_name, value)
  ) attrs

let adjust_foreign_attrs attrs =
  List.map (fun (name, value) ->
    match Hashtbl.find_opt foreign_attr_adjustments_tbl (lowercase name) with
    | Some (prefix, local, _ns) ->
      if prefix = "" then (local, value)
      else (prefix ^ ":" ^ local, value)
    | None -> (name, value)
  ) attrs