// LexLua.cxx - lexer for Lua language
// Written by Paul Winwood

#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <stdarg.h>
#include <stdio.h>
#include <fcntl.h>

#include "Platform.h"

#include "PropSet.h"
#include "Accessor.h"
#include "KeyWords.h"
#include "Scintilla.h"
#include "SciLexer.h"

inline bool isLuaOperator(char ch) {
	if (isalnum(ch))
		return false;
	// '.' left out as it is used to make up numbers
	if (ch == '*' || ch == '/' ||ch == '-' || ch == '+' ||
		ch == '(' || ch == ')' || ch == '=' ||
		ch == '{' || ch == '}' || ch == '~' ||
		ch == '[' || ch == ']' || ch == ';' ||
		ch == '<' || ch == '>' || ch == ',' ||
		ch == '.' || ch == '^' || ch == '%' || ch == ':')
			return true;
	return false;
}

static void classifyWordLua(unsigned int start,
							unsigned int end,
							WordList	&keywords,
							Accessor	&styler)
{
    char s[100];
    bool wordIsNumber = isdigit(styler[start]) || (styler[start] == '.');

    for (unsigned int i = 0; i < end - start + 1 && i < 30; i++)
	{
	    s[i] = styler[start + i];
	    s[i + 1] = '\0';
	}

    char chAttr = SCE_LUA_IDENTIFIER;

    if (wordIsNumber)
	    chAttr = SCE_LUA_NUMBER;
    else
	{
	    if (keywords.InList(s))
		{
		    chAttr = SCE_LUA_WORD;
		}
	}
    styler.ColourTo(end, chAttr);
}

static void ColouriseLuaDoc(unsigned int startPos,
						    int 		 length,
						    int 		 initStyle,
						    WordList    *keywordlists[],
						    Accessor    &styler)
{

    WordList &keywords = *keywordlists[0];

    styler.StartAt(startPos);
    styler.GetLine(startPos);

    int  state = initStyle;
    char chPrev = ' ';
    char chNext = styler[startPos];
    unsigned int lengthDoc = startPos + length;
    bool firstChar = true;
    int  literalString = 0;

    styler.StartSegment(startPos);
    for (unsigned int i = startPos; i <= lengthDoc; i++)
	{
	    char ch = chNext;
	    chNext = styler.SafeGetCharAt(i + 1);

	    if (styler.IsLeadByte(ch))
		{
		    chNext = styler.SafeGetCharAt(i + 2);
		    chPrev = ' ';
		    i += 1;
		    continue;
		}

	    if (state == SCE_LUA_STRINGEOL)
		{
		    if (ch != '\r' && ch != '\n')
			{
			    styler.ColourTo(i-1, state);
			    state = SCE_LUA_DEFAULT;
			}
		}

	    if (state == SCE_LUA_LITERALSTRING && ch == '[' && chNext == '[')
		{
		    literalString++;
		}
	    else if (state == SCE_LUA_DEFAULT)
		{
		    if (ch == '-' && chNext == '-')
			{
			    styler.ColourTo(i-1, state);
			    state = SCE_LUA_COMMENTLINE;
			}
		    else if (ch == '[' && chNext == '[')
			{
			    state = SCE_LUA_LITERALSTRING;
			    literalString = 1;
			}
		    else if (ch == '\"')
			{
			    styler.ColourTo(i-1, state);
			    state = SCE_LUA_STRING;
			}
		    else if (ch == '\'')
			{
			    styler.ColourTo(i-1, state);
			    state = SCE_LUA_CHARACTER;
			}
		    else if (ch == '$' && firstChar)
			{
			    styler.ColourTo(i-1, state);
			    state = SCE_LUA_PREPROCESSOR;
			}
			else if (ch == '#' && firstChar)	// Should be only on the first line of the file! Cannot be tested here
			{
				styler.ColourTo(i-1, state);
				state = SCE_LUA_COMMENTLINE;
			}
		    else if (isLuaOperator(ch))
			{
			    styler.ColourTo(i-1, state);
			    styler.ColourTo(i, SCE_LUA_OPERATOR);
			}
		    else if (iswordstart(ch))
			{
			    styler.ColourTo(i-1, state);
			    state = SCE_LUA_WORD;
			}
		}
	    else if (state == SCE_LUA_WORD)
		{
		    if (!iswordchar(ch))
			{
			    classifyWordLua(styler.GetStartSegment(), i - 1, keywords, styler);
			    state = SCE_LUA_DEFAULT;
			    if (ch == '[' && chNext == '[')
				{
				    literalString = 1;
				    state = SCE_LUA_LITERALSTRING;
				}
			    else if (ch == '-' && chNext == '-')
				{
				    state = SCE_LUA_COMMENTLINE;
				}
			    else if (ch == '\"')
				{
				    state = SCE_LUA_STRING;
				}
			    else if (ch == '\'')
				{
				    state = SCE_LUA_CHARACTER;
				}
			    else if (ch == '$' && firstChar)
				{
				    state = SCE_LUA_PREPROCESSOR;
				}
			    else if (isLuaOperator(ch))
				{
				    styler.ColourTo(i, SCE_LUA_OPERATOR);
				}
			}
			else if (ch == '.' && chNext == '.')
			{
			    classifyWordLua(styler.GetStartSegment(), i - 1, keywords, styler);
				styler.ColourTo(i, SCE_LUA_OPERATOR);
				state = SCE_LUA_DEFAULT;
			}
		}
	    else
		{
		    if (state == SCE_LUA_LITERALSTRING)
			{
			    if (ch == ']' && (chPrev == ']') && (--literalString == 0))
				{
				    styler.ColourTo(i, state);
				    state = SCE_LUA_DEFAULT;
				}
			}
		    else if (state == SCE_LUA_PREPROCESSOR)
			{
			    if ((ch == '\r' || ch == '\n') && (chPrev != '\\'))
				{
				    styler.ColourTo(i-1, state);
				    state = SCE_LUA_DEFAULT;
				}
			}
		    else if (state == SCE_LUA_COMMENTLINE)
			{
			    if (ch == '\r' || ch == '\n')
				{
				    styler.ColourTo(i-1, state);
				    state = SCE_LUA_DEFAULT;
				}
			}
		    else if (state == SCE_LUA_STRING)
			{
			    if ((ch == '\r' || ch == '\n') && (chPrev != '\\'))
				{
				    styler.ColourTo(i-1, state);
				    state = SCE_LUA_STRINGEOL;
				}
			    else if (ch == '\\')
				{
				    if (chNext == '\"' || chNext == '\\')
					{
					    i++;
					    ch = chNext;
					    chNext = styler.SafeGetCharAt(i + 1);
					}
				}
			    else if (ch == '\"')
				{
				    styler.ColourTo(i, state);
				    state = SCE_LUA_DEFAULT;
				    i++;
				    ch = chNext;
				    chNext = styler.SafeGetCharAt(i + 1);
				}
			}
		    else if (state == SCE_LUA_CHARACTER)
			{
			    if ((ch == '\r' || ch == '\n') && (chPrev != '\\'))
				{
				    styler.ColourTo(i-1, state);
				    state = SCE_LUA_STRINGEOL;
				}
			    else if (ch == '\\')
				{
				    if (chNext == '\'' || chNext == '\\')
					{
					    i++;
					    ch = chNext;
					    chNext = styler.SafeGetCharAt(i + 1);
					}
				}
			    else if (ch == '\'')
				{
				    styler.ColourTo(i, state);
				    state = SCE_LUA_DEFAULT;
				    i++;
				    ch = chNext;
				    chNext = styler.SafeGetCharAt(i + 1);
				}
			}

		    if (state == SCE_LUA_DEFAULT)
			{
			    if (ch == '-' && chNext == '-')
				{
				    state = SCE_LUA_COMMENTLINE;
				}
			    else if (ch == '\"')
				{
				    state = SCE_LUA_STRING;
				}
			    else if (ch == '\'')
				{
				    state = SCE_LUA_CHARACTER;
				}
			    else if (ch == '$' && firstChar)
				{
				    state = SCE_LUA_PREPROCESSOR;
				}
			    else if (iswordstart(ch))
				{
				    state = SCE_LUA_WORD;
				}
			    else if (isLuaOperator(ch))
				{
				    styler.ColourTo(i, SCE_LUA_OPERATOR);
				}
			}
		}
	    chPrev = ch;
	    firstChar = (ch == '\r' || ch == '\n');
	}
    styler.ColourTo(lengthDoc - 1, state);
}

LexerModule lmLua(SCLEX_LUA, ColouriseLuaDoc);