// Scintilla source code edit control
/** @file LexPython.cxx
 ** Lexer for Python.
 **/
// Copyright 1998-2001 by Neil Hodgson <neilh@scintilla.org>
// The License.txt file describes the conditions under which this software may be distributed.

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

#include "Platform.h"

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

/* Returns true if the "as" word that begins at start follows an import statement */
static bool IsImportAs(unsigned int start, Accessor &styler) {
	unsigned int i;
	unsigned int j;
	char s[10];

	/* Find any import before start but after any statement terminator or quote */
	i = start;
	while (i > 0) {
		char ch = styler[i - 1];

		if (ch == '\n' || ch == '\r' || ch == ';' || ch == '\'' || ch == '"' || ch == '`')
			break;
		if (ch == 't' && i > 5) {
			for (j = 0; j < 6; j++)
				s[j] = styler[(i - 6) + j];
			s[j] = '\0';
			if (strcmp(s, "import") == 0)
				return true;
		}
		i--;
	}

        return false;
}

static void ClassifyWordPy(unsigned int start, unsigned int end, WordList &keywords, Accessor &styler, char *prevWord) {
	char s[100];
	bool wordIsNumber = isdigit(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_P_IDENTIFIER;
	if (0 == strcmp(prevWord, "class"))
		chAttr = SCE_P_CLASSNAME;
	else if (0 == strcmp(prevWord, "def"))
		chAttr = SCE_P_DEFNAME;
	else if (wordIsNumber)
		chAttr = SCE_P_NUMBER;
	else if (keywords.InList(s))
		chAttr = SCE_P_WORD;
	else if (strcmp(s, "as") == 0 && IsImportAs(start, styler))
		chAttr = SCE_P_WORD;
	// make sure that dot-qualifiers inside the word are lexed correct
	else for (unsigned int i = 0; i < end - start + 1; i++) {
		if (styler[start + i] == '.') {
			styler.ColourTo(start + i - 1, chAttr);
			styler.ColourTo(start + i, SCE_P_OPERATOR);
		}
	}
	styler.ColourTo(end, chAttr);
	strcpy(prevWord, s);
}

static bool IsPyComment(Accessor &styler, int pos, int len) {
	return len>0 && styler[pos]=='#';
}

static bool IsPyStringStart(char ch, char chNext, char chNext2) {
	if (ch == '\'' || ch == '"')
		return true;
	if (ch == 'u' || ch == 'U') {
		if (chNext == '"' || chNext == '\'')
			return true;
		if ((chNext == 'r' || chNext == 'R') && (chNext2 == '"' || chNext2 == '\''))
			return true;
	}
	if ((ch == 'r' || ch == 'R') && (chNext == '"' || chNext == '\''))
		return true;

	return false;
}

static bool IsPyWordStart(char ch, char chNext, char chNext2) {
	return (iswordchar(ch) && !IsPyStringStart(ch, chNext, chNext2));
}

/* Return the state to use for the string starting at i; *nextIndex will be set to the first index following the quote(s) */
static int GetPyStringState(Accessor &styler, int i, int *nextIndex) {
	char ch = styler.SafeGetCharAt(i);
	char chNext = styler.SafeGetCharAt(i + 1);

	// Advance beyond r, u, or ur prefix, but bail if there are any unexpected chars
	if (ch == 'r' || ch == 'R') {
		i++;
		ch = styler.SafeGetCharAt(i);
		chNext = styler.SafeGetCharAt(i + 1);
	}
	else if (ch == 'u' || ch == 'U') {
		if (chNext == 'r' || chNext == 'R')
			i += 2;
		else
			i += 1;
		ch = styler.SafeGetCharAt(i);
		chNext = styler.SafeGetCharAt(i + 1);
	}

	if (ch != '"' && ch != '\'') {
		*nextIndex = i + 1;
		return SCE_P_DEFAULT;
	}

	if (ch == chNext && ch == styler.SafeGetCharAt(i + 2)) {
		*nextIndex = i + 3;

		if (ch == '"')
			return SCE_P_TRIPLEDOUBLE;
		else
			return SCE_P_TRIPLE;
	} else {
		*nextIndex = i + 1;

		if (ch == '"')
			return SCE_P_STRING;
		else
			return SCE_P_CHARACTER;
	}
}

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

	int lengthDoc = startPos + length;

	// Backtrack to previous line in case need to fix its tab whinging
	if (startPos > 0) {
		int lineCurrent = styler.GetLine(startPos);
		if (lineCurrent > 0) {
			startPos = styler.LineStart(lineCurrent-1);
			if (startPos == 0)
				initStyle = SCE_P_DEFAULT;
			else
				initStyle = styler.StyleAt(startPos-1);
		}
	}

	// Python uses a different mask because bad indentation is marked by oring with 32
	styler.StartAt(startPos, 127);

	WordList &keywords = *keywordlists[0];

	int whingeLevel = styler.GetPropertyInt("tab.timmy.whinge.level");
	char prevWord[200];
	prevWord[0] = '\0';
	if (length == 0)
		return ;

	int state = initStyle & 31;

	int nextIndex = 0;
	char chPrev = ' ';
	char chPrev2 = ' ';
	char chNext = styler[startPos];
	styler.StartSegment(startPos);
	bool atStartLine = true;
	int spaceFlags = 0;
	for (int i = startPos; i < lengthDoc; i++) {

		if (atStartLine) {
			char chBad = static_cast<char>(64);
			char chGood = static_cast<char>(0);
			char chFlags = chGood;
			if (whingeLevel == 1) {
				chFlags = (spaceFlags & wsInconsistent) ? chBad : chGood;
			} else if (whingeLevel == 2) {
				chFlags = (spaceFlags & wsSpaceTab) ? chBad : chGood;
			} else if (whingeLevel == 3) {
				chFlags = (spaceFlags & wsSpace) ? chBad : chGood;
			} else if (whingeLevel == 4) {
				chFlags = (spaceFlags & wsTab) ? chBad : chGood;
			}
			styler.SetFlags(chFlags, static_cast<char>(state));
			atStartLine = false;
		}

		char ch = chNext;
		chNext = styler.SafeGetCharAt(i + 1);
		char chNext2 = styler.SafeGetCharAt(i + 2);

		if ((ch == '\r' && chNext != '\n') || (ch == '\n') || (i == lengthDoc)) {
			if ((state == SCE_P_DEFAULT) || (state == SCE_P_TRIPLE) || (state == SCE_P_TRIPLEDOUBLE)) {
				// Perform colourisation of white space and triple quoted strings at end of each line to allow
				// tab marking to work inside white space and triple quoted strings
				styler.ColourTo(i, state);
			}
			atStartLine = true;
		}

		if (styler.IsLeadByte(ch)) {
			chNext = styler.SafeGetCharAt(i + 2);
			chPrev = ' ';
			chPrev2 = ' ';
			i += 1;
			continue;
		}

		if (state == SCE_P_STRINGEOL) {
			if (ch != '\r' && ch != '\n') {
				styler.ColourTo(i - 1, state);
				state = SCE_P_DEFAULT;
			}
		}
		if (state == SCE_P_DEFAULT) {
			if (IsPyWordStart(ch, chNext, chNext2)) {
				styler.ColourTo(i - 1, state);
				state = SCE_P_WORD;
			} else if (ch == '#') {
				styler.ColourTo(i - 1, state);
				state = chNext == '#' ? SCE_P_COMMENTBLOCK : SCE_P_COMMENTLINE;
			} else if (IsPyStringStart(ch, chNext, chNext2)) {
				styler.ColourTo(i - 1, state);
				state = GetPyStringState(styler, i, &nextIndex);
				if (nextIndex != i + 1) {
					i = nextIndex - 1;
					ch = ' ';
					chPrev = ' ';
					chNext = styler.SafeGetCharAt(i + 1);
				}
			} else if (isoperator(ch)) {
				styler.ColourTo(i - 1, state);
				styler.ColourTo(i, SCE_P_OPERATOR);
			}
		} else if (state == SCE_P_WORD) {
			if (!iswordchar(ch)) {
				ClassifyWordPy(styler.GetStartSegment(), i - 1, keywords, styler, prevWord);
				state = SCE_P_DEFAULT;
				if (ch == '#') {
					state = chNext == '#' ? SCE_P_COMMENTBLOCK : SCE_P_COMMENTLINE;
				} else if (IsPyStringStart(ch, chNext, chNext2)) {
					styler.ColourTo(i - 1, state);
					state = GetPyStringState(styler, i, &nextIndex);
					if (nextIndex != i + 1) {
						i = nextIndex - 1;
						ch = ' ';
						chPrev = ' ';
						chNext = styler.SafeGetCharAt(i + 1);
					}
				} else if (isoperator(ch)) {
					styler.ColourTo(i, SCE_P_OPERATOR);
				}
			}
		} else {
			if (state == SCE_P_COMMENTLINE || state == SCE_P_COMMENTBLOCK) {
				if (ch == '\r' || ch == '\n') {
					styler.ColourTo(i - 1, state);
					state = SCE_P_DEFAULT;
				}
			} else if (state == SCE_P_STRING) {
				if ((ch == '\r' || ch == '\n') && (chPrev != '\\')) {
					styler.ColourTo(i - 1, state);
					state = SCE_P_STRINGEOL;
				} else if (ch == '\\') {
					if (chNext == '\"' || chNext == '\'' || chNext == '\\') {
						i++;
						ch = chNext;
						chNext = styler.SafeGetCharAt(i + 1);
					}
				} else if (ch == '\"') {
					styler.ColourTo(i, state);
					state = SCE_P_DEFAULT;
				}
			} else if (state == SCE_P_CHARACTER) {
				if ((ch == '\r' || ch == '\n') && (chPrev != '\\')) {
					styler.ColourTo(i - 1, state);
					state = SCE_P_STRINGEOL;
				} else if (ch == '\\') {
					if (chNext == '\"' || chNext == '\'' || chNext == '\\') {
						i++;
						ch = chNext;
						chNext = styler.SafeGetCharAt(i + 1);
					}
				} else if (ch == '\'') {
					styler.ColourTo(i, state);
					state = SCE_P_DEFAULT;
				}
			} else if (state == SCE_P_TRIPLE) {
				if (ch == '\'' && chPrev == '\'' && chPrev2 == '\'') {
					styler.ColourTo(i, state);
					state = SCE_P_DEFAULT;
				}
			} else if (state == SCE_P_TRIPLEDOUBLE) {
				if (ch == '\"' && chPrev == '\"' && chPrev2 == '\"') {
					styler.ColourTo(i, state);
					state = SCE_P_DEFAULT;
				}
			}
		}
		chPrev2 = chPrev;
		chPrev = ch;
	}
	if (state == SCE_P_WORD) {
		ClassifyWordPy(styler.GetStartSegment(), lengthDoc, keywords, styler, prevWord);
	} else {
		styler.ColourTo(lengthDoc, state);
	}
}

static void FoldPyDoc(unsigned int startPos, int length, int initStyle,
						   WordList *[], Accessor &styler) {
	int lengthDoc = startPos + length;

	// Backtrack to previous line in case need to fix its fold status
	int lineCurrent = styler.GetLine(startPos);
	if (startPos > 0) {
		if (lineCurrent > 0) {
			lineCurrent--;
			startPos = styler.LineStart(lineCurrent);
			if (startPos == 0)
				initStyle = SCE_P_DEFAULT;
			else
				initStyle = styler.StyleAt(startPos-1);
		}
	}
	int state = initStyle & 31;
	int spaceFlags = 0;
	int indentCurrent = styler.IndentAmount(lineCurrent, &spaceFlags, IsPyComment);
	if ((state == SCE_P_TRIPLE) || (state == SCE_P_TRIPLEDOUBLE))
		indentCurrent |= SC_FOLDLEVELWHITEFLAG;
	char chNext = styler[startPos];
	for (int i = startPos; i < lengthDoc; i++) {
		char ch = chNext;
		chNext = styler.SafeGetCharAt(i + 1);
		int style = styler.StyleAt(i) & 31;

		if ((ch == '\r' && chNext != '\n') || (ch == '\n') || (i == lengthDoc)) {
			int lev = indentCurrent;
			int indentNext = styler.IndentAmount(lineCurrent + 1, &spaceFlags, IsPyComment);
			if ((style == SCE_P_TRIPLE) || (style== SCE_P_TRIPLEDOUBLE))
				indentNext |= SC_FOLDLEVELWHITEFLAG;
			if (!(indentCurrent & SC_FOLDLEVELWHITEFLAG)) {
				// Only non whitespace lines can be headers
				if ((indentCurrent & SC_FOLDLEVELNUMBERMASK) < (indentNext & SC_FOLDLEVELNUMBERMASK)) {
					lev |= SC_FOLDLEVELHEADERFLAG;
				} else if (indentNext & SC_FOLDLEVELWHITEFLAG) {
					// Line after is blank so check the next - maybe should continue further?
					int spaceFlags2 = 0;
					int indentNext2 = styler.IndentAmount(lineCurrent + 2, &spaceFlags2, IsPyComment);
					if ((indentCurrent & SC_FOLDLEVELNUMBERMASK) < (indentNext2 & SC_FOLDLEVELNUMBERMASK)) {
						lev |= SC_FOLDLEVELHEADERFLAG;
					}
				}
			}
			indentCurrent = indentNext;
			styler.SetLevel(lineCurrent, lev);
			lineCurrent++;
		}
	}
}
						   
LexerModule lmPython(SCLEX_PYTHON, ColourisePyDoc, "python", FoldPyDoc);