#ifndef __JetParser_h__
#define __JetParser_h__

#include "JetAST.h"
#include <string>
#include <map>
#include <utility>

namespace jetc {

   // Standalone parser for a subset of the JET template grammar. Mirrors the
   // character-level grammar implemented by JetCore's Tag::parseContainer /
   // Tag::Tag (attribute scanning, same-tag-name nesting depth, the <if>
   // <else> split) closely enough for well-formed templates, but is a fresh
   // implementation - it does not reuse JetCore's Tag classes, since those
   // fuse parsing and execution together (a real parse/execute split there
   // is a separate, larger refactor). Anything outside the modeled subset
   // (set/if/for/while/$[...]/literal text) is captured as an exact raw
   // source span and left for the existing interpreter (Tag::interpretSpan)
   // to run at compiled-program runtime, so unsupported constructs degrade
   // gracefully instead of failing to compile.
   class Parser {
    public:
      explicit Parser(const std::string &src) : s(src), pos(0) {}

      std::vector<NodePtr> parseNodes();

    private:
      std::string s;
      size_t pos;
      size_t nextId = 0;

      bool eof() const { return pos >= s.size(); }
      bool starts(const std::string &lit) const;
      static bool isNameChar(char c);
      void skipWs();
      std::string readName();
      std::string peekTagName(size_t at) const;

      bool matchTagOpen(const std::string &name, size_t at) const;
      bool matchTagClose(const std::string &name, size_t at) const;

      // p points at '<' of some tag's opening; advances p past its '>' or
      // "/>", skipping quoted attribute values. Returns true if self-closing.
      bool skipOpenTag(size_t &p) const;

      std::map<std::string, std::string> parseAttrs(bool &hasContainer);

      // Scans forward from bodyStart (just after the opening tag's '>') for
      // tagName's matching close, tracking same-tag-name nesting depth and
      // (if lookForElse) a depth==1 "<else>" split point.
      // Returns {closePos, elsePos} (elsePos == npos if not found/not sought).
      std::pair<size_t, size_t> scanBody(size_t bodyStart, const std::string &tagName, bool lookForElse);

      std::vector<NodePtr> parseSub(size_t start, size_t end);

      NodePtr parseVar();
      NodePtr parseSet();
      NodePtr parseIf();
      NodePtr parseFor();
      NodePtr parseWhile();
      NodePtr parseFallback();

      std::string newId(const std::string &prefix) { return prefix + std::to_string(nextId++) + "_"; }
   };

}

#endif