#include "cpp.h"

#include "bnf.h"
#include "cppbnf.h"
#include "debug.h"
#include "lexer.h"
#include "grammer.h"
#include "minicc.h"

#include <gtest/gtest.h>
#include <gmock/gmock.h>

#include <functional>
#include <unordered_set>
#include <unordered_map>

using namespace Gram;

CPP::CPP(){}

CPP::~CPP(){}

// Phase 1: Map physical character set to basic source character set
void CPP::source_charset_map()
{
 // TODO
}

// Phase 2: Escape backslashed line endings
void CPP::backslash_escape()
{
 // TODO
}

// Phase 3: Parse preprocessing tokens, TODO: discard comments
std::vector<Token> CPP::preprocessing_tokenize(const std::string& s)
{
 auto bnf{SubBNF(CPPBNF::GetCppBNFLex(), "preprocessing-token")};
 
 Lex::Lexer lexer(bnf, "preprocessing-token");

 return lexer.Lex(s);
}

// Phase 4: Preprocessing
void CPP::preprocess()
{
 // TODO
}

// Phase 5: Map chars and strings to execution charset
void CPP::execution_charset_map()
{
 // TODO
}

// Phase 6: Concatenate adjacent string literals
void CPP::concatenate_strings()
{
 // TODO
}

std::string CPP::valueOfNode(index_t node_index, const std::vector<TreeNode>& Tree)
{
 std::string result;

 std::vector<int32_t> todo(1, int32_t(node_index));

 while (!todo.empty()) {
  int32_t current_index = todo.back();
  todo.pop_back();

  // visit node if token
  if (ChildIdIsToken(current_index)) {
   result += m_code[TokenIdFromChildId(current_index)];
  } else {

   const TreeNode &node{Tree[current_index]};

   // iterate backwards in childs, to get depth-first search in tree, from the beginning
   std::for_each(node.child_ids.rbegin(), node.child_ids.rend(), [&](int32_t child){
    todo.push_back(child);
   });
  }
 }

 return result;
};

namespace {
 std::unordered_set<std::string> pp_types {
  "identifier",
  "pp-number",
  "character-literal",
  "user-defined-character-literal",
  "string-literal",
  "user-defined-string-literal",
  "preprocessing-op-or-punc"
 };

 std::unordered_set<std::string> keywords {
  "alignas",
  "alignof",
  "asm",
  "auto",
  "bool",
  "break",
  "case",
  "catch",
  "char",
  "char8_t",
  "char16_t",
  "char32_t",
  "class",
  "concept",
  "const",
  "consteval",
  "constexpr",
  "constinit",
  "const_cast",
  "continue",
  "co_await",
  "co_return",
  "co_yield",
  "decltype",
  "default",
  "delete",
  "do",
  "double",
  "dynamic_cast",
  "else",
  "enum",
  "explicit",
  "export",
  "extern",
  "false",
  "float",
  "for",
  "friend",
  "goto",
  "if",
  "inline",
  "int",
  "long",
  "mutable",
  "namespace",
  "new",
  "noexcept",
  "nullptr",
  "operator",
  "private",
  "protected",
  "public",
  "register",
  "reinterpret_cast",
  "requires",
  "return",
  "short",
  "signed",
  "sizeof",
  "static",
  "static_assert",
  "static_cast",
  "struct",
  "switch",
  "template",
  "this",
  "thread_local",
  "throw",
  "true",
  "try",
  "typedef",
  "typeid",
  "typename",
  "union",
  "unsigned",
  "using",
  "virtual",
  "void",
  "volatile",
  "wchar_t",
  "while",
 };
}

// Phase 7.a: Create tokens from preprocessing tokens
std::vector<Token> CPP::tokens_from_pptokens(const std::vector<Token>& pp_tokens)
{
 std::vector<Token> result;

 // "identifier" + value -> "identifier" + value, except identifiers from table 5.11, p.14 -> keyword as value, value
 // "pp-number" + value -> "literal" + value
 // "character-literal" -> "literal" + value
 // "user-defined-character-literal" -> "literal" + value
 // "string-literal" -> "literal" + value
 // "user-defined-string-literal" -> "literal" + value
 // "preprocessing-op-or-punc" -> value+value (operator,punctuator)
 
 for (auto& token: pp_tokens) {
  if (pp_types.find(token.type) != pp_types.end()) {
   if (token.type == "identifier") {
    if (keywords.find(token.value) != keywords.end())
     result.emplace_back(Token{token.value, token.value});
    else
     result.emplace_back(Token{"identifier"s, token.value});
   }
   else if (token.type == "preprocessing-op-or-punc")
    result.emplace_back(Token{token.value, token.value});
   else
    result.emplace_back(Token{"literal", token.value});
  } else
   throw std::runtime_error("Unhandled preprocessing token: "s + token.value + " ("s + token.type + ")"s);
 }
 return result;
}

// Phase 7.b: Grammar Analysis
std::vector<Gram::TreeNode> CPP::analysis(const std::vector<Token>& tokens)
{
 auto bnf = SubBNF(CPPBNF::GetCppBNFGram(), "translation-unit");

 Gram::Compiler compiler(bnf, "translation-unit");

 return compiler.compile(tokens);
}

namespace {

 CPP::map_type map_translation_unit {
  //{"top-level-declaration-seq", [](){}},
  {"top-level-declaration-seq/top-level-declaration/declaration/function-definition", [](){}},
 };

} // anonymous namespace

void CPP::traverse(index_t node_id, map_type& map)
{
 // TODO
}

// Phase 7.c: Translate
void CPP::translate()
{
 if (m_nodes.size() == 0)
  throw std::runtime_error("ICE: Tree is empty");

 traverse(0, map_translation_unit);
}

// Phase 8: Instantiate objects
void CPP::instantiate()
{
 // TODO
}

// Phase 9: Link libraries
void CPP::link()
{
 // TODO
}

// phases of translation, according to standard
void CPP::compile(const std::string& code)
{
 source_charset_map();
 
 backslash_escape();
 
 auto pp_tokens = preprocessing_tokenize(code);
 
 preprocess();
 
 execution_charset_map();
 
 concatenate_strings();
 
 auto tokens = tokens_from_pptokens(pp_tokens);
 m_nodes = analysis(tokens);
 translate();
 
 instantiate();
 
 link();
}

std::vector<uint8_t> CPP::getCode()
{
 // TODO
 return {
            0x48, 0xc7, 0xc0, 0x3c, 0x00, 0x00, 0x00, // mov    $0x3c,%rax     # syscall 60
            0x48, 0x31, 0xff,                         // xor    %rdi,%rdi      # exit code 0
            0x0f, 0x05,                               // syscall
 };
}

std::vector<uint8_t> CPP::getData()
{
 return {}; // TODO
}