/*
 * Copyright 2004-2005, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
 * Distributed under the terms of the MIT License.
 */


#include "RTF.h"

#include <DataIO.h>

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


static char read_char(BDataIO &stream, bool endOfFileAllowed = false) throw (status_t);
static int32 parse_integer(char first, BDataIO &stream, char &_last) throw (status_t);


using namespace RTF;


static char
read_char(BDataIO &stream, bool endOfFileAllowed) throw (status_t)
{
	char c;
	ssize_t bytesRead = stream.Read(&c, 1);
	
	if (bytesRead < B_OK)
		throw (status_t)bytesRead;

	if (bytesRead == 0 && !endOfFileAllowed)
		throw (status_t)B_ERROR;

	return c;
}


static int32
parse_integer(char first, BDataIO &stream, char &_last) throw (status_t)
{
	int32 integer = 0;
	int32 count = 0;

	char digit = first;

	if (digit == '\0')
		digit = read_char(stream);

	while (true) {
		if (isdigit(digit)) {
			integer = integer * 10 + digit - '0';
			count++;
		} else {
			_last = digit;
			goto out;
		}

		digit = read_char(stream);
	}

out:
	if (count == 0)
		throw (status_t)B_BAD_TYPE;

	return integer;
}


static void
dump(Element &element, int32 level = 0)
{
	printf("%03ld:", level);
	for (int32 i = 0; i < level; i++)
		printf("  ");

	if (RTF::Header *header = dynamic_cast<RTF::Header *>(&element)) {
		printf("<RTF header, major version %ld>\n", header->Version());
	} else if (RTF::Command *command = dynamic_cast<RTF::Command *>(&element)) {
		printf("<Command: %s", command->Name());
		if (command->HasOption())
			printf(", Option %ld", command->Option());
		puts(">");
	} else if (RTF::Text *text = dynamic_cast<RTF::Text *>(&element)) {
		printf("<Text>");
		puts(text->String());
	} else if (dynamic_cast<RTF::Group *>(&element) != NULL)
		puts("<Group>");

	if (RTF::Group *group = dynamic_cast<RTF::Group *>(&element)) {
		for (uint32 i = 0; i < group->CountElements(); i++)
			dump(*group->ElementAt(i), level + 1);
	}
}


//	#pragma mark -


Parser::Parser(BDataIO &stream)
	:
	fStream(stream),
	fIdentified(false)
{
}


status_t
Parser::Identify()
{
	char header[5];
	if (fStream.Read(header, sizeof(header)) < (ssize_t)sizeof(header))
		return B_IO_ERROR;

	if (strncmp(header, "{\\rtf", 5))
		return B_BAD_TYPE;

	fIdentified = true;
	return B_OK;
}


status_t
Parser::Parse(Header &header)
{
	if (!fIdentified && Identify() != B_OK)
		return B_BAD_TYPE;

	try {
		int32 openBrackets = 1;

		// since we already preparsed parts of the RTF header, the header
		// is handled here directly
		char last;
		header.Parse('\0', fStream, last);

		Group *parent = &header;
		char c = last;

		while (true) {
			Element *element = NULL;

			switch (c) {
				case '{':
					openBrackets++;
					parent->AddElement(element = new Group());
					parent = static_cast<Group *>(element);
					break;

				case '\\':
					parent->AddElement(element = new Command());
					break;

				case '}':
					openBrackets--;
					parent->DetermineDestination();
					parent = parent->Parent();
					// supposed to fall through
				case '\n':
				case '\r':
				{
					ssize_t bytesRead = fStream.Read(&c, 1);
					if (bytesRead < B_OK)
						throw (status_t)bytesRead;
					else if (bytesRead != 1) {
						// this is the only valid exit status
						if (openBrackets == 0)
							return B_OK;

						throw B_ERROR;
					}
					continue;
				}

				default:
					parent->AddElement(element = new Text());
					break;
			}

			if (element == NULL)
				throw (status_t)B_ERROR;

			element->Parse(c, fStream, last);
			c = last;
		}
	} catch (status_t status) {
		return status;
	}

	return B_OK;
}


//	#pragma mark -


Element::Element()
	:
	fParent(NULL)
{
}


Element::~Element()
{
}


void
Element::SetParent(Group *parent)
{
	fParent = parent;
}


Group *
Element::Parent() const
{
	return fParent;
}


void
Element::PrintToStream(int32 level)
{
	dump(*this, level);
}


//	#pragma mark -


Group::Group()
	:
	fDestination(OTHER_DESTINATION)
{
}


Group::~Group()
{
	Element *element;
	while ((element = (Element *)fElements.RemoveItem(0L)) != NULL) {
		delete element;
	}
}


void
Group::Parse(char first, BDataIO &stream, char &last) throw (status_t)
{
	if (first == '\0')
		first = read_char(stream);

	if (first != '{')
		throw (status_t)B_BAD_TYPE;

	last = read_char(stream);
}


status_t
Group::AddElement(Element *element)
{
	if (element == NULL)
		return B_BAD_VALUE;

	if (fElements.AddItem(element)) {
		element->SetParent(this);
		return B_OK;
	}

	return B_NO_MEMORY;
}


uint32
Group::CountElements() const
{
	return (uint32)fElements.CountItems();
}


Element *
Group::ElementAt(uint32 index) const
{
	return static_cast<Element *>(fElements.ItemAt(index));
}


Command *
Group::FindDefinition(const char *name, int32 index) const
{
	if (index < 0)
		return NULL;

	Element *element;
	int32 number = 0;
	for (uint32 i = 0; (element = ElementAt(i)) != NULL; i++) {
		if (Text *text = dynamic_cast<Text *>(element)) {
			// the ';' indicates the next definition
			if (!strcmp(text->String(), ";"))
				number++;
		} else if (Command *command = dynamic_cast<Command *>(element)) {
			if (command != NULL
				&& !strcmp(name, command->Name())
				&& number == index)
				return command;
		}
	}

	return NULL;
}


Group *
Group::FindGroup(const char *name) const
{
	Element *element;
	for (uint32 i = 0; (element = ElementAt(i)) != NULL; i++) {
		Group *group = dynamic_cast<Group *>(element);
		if (group == NULL)
			continue;

		Command *command = dynamic_cast<Command *>(group->ElementAt(0));
		if (command != NULL && !strcmp(name, command->Name()))
			return group;
	}

	return NULL;
}


const char *
Group::Name() const
{
	Command *command = dynamic_cast<Command *>(ElementAt(0));
	if (command != NULL)
		return command->Name();

	return NULL;
}


void
Group::DetermineDestination()
{
	const char *name = Name();
	if (name == NULL) {
		fDestination = TEXT_DESTINATION;
		return;
	}

	if (!strcmp(name, "*")) {
		fDestination = COMMENT_DESTINATION;
		return;
	}

	const char *texts[] = {"rtf", "sect", "par"};
	for (uint32 i = 0; i < sizeof(texts) / sizeof(texts[0]); i++) {
		if (!strcmp(name, texts[i])) {
			fDestination = TEXT_DESTINATION;
			return;
		}
	}

	fDestination = OTHER_DESTINATION;
}


group_destination
Group::Destination() const
{
	return fDestination;
}


//	#pragma mark -


Header::Header()
	:
	fVersion(0)
{
}


Header::~Header()
{
}


void
Header::Parse(char first, BDataIO &stream, char &last) throw (status_t)
{
	// The stream has been peeked into by the parser already, and
	// only the version follows in the stream -- let's pick it up

	fVersion = parse_integer(first, stream, last);

	// recreate "rtf" command to name this group

	Command *command = new Command();
	command->SetName("rtf");
	command->SetOption(fVersion);

	AddElement(command);
}


int32
Header::Version() const
{
	return fVersion;
}


const char *
Header::Charset() const
{
	Command *command = dynamic_cast<Command *>(ElementAt(1));
	if (command == NULL)
		return NULL;

	return command->Name();
}


rgb_color 
Header::Color(int32 index)
{
	rgb_color color = {0, 0, 0, 255};

	Group *colorTable = FindGroup("colortbl");

	if (colorTable != NULL) {
		if (Command *gun = colorTable->FindDefinition("red", index))
			color.red = gun->Option();
		if (Command *gun = colorTable->FindDefinition("green", index))
			color.green = gun->Option();
		if (Command *gun = colorTable->FindDefinition("blue", index))
			color.blue = gun->Option();
	}

	return color;
}


//	#pragma mark -


Text::Text()
{
}


Text::~Text()
{
	SetTo(NULL);
}


void
Text::Parse(char first, BDataIO &stream, char &last) throw (status_t)
{
	char c = first;
	if (c == '\0')
		c = read_char(stream);
	
	fText = "";

	while (true) {
		if (c == '\\' || c == '}')
			break;

		// ToDo: this is horribly inefficient with BStrings
		fText.Append(c, 1);
		c = read_char(stream);
	}

	// ToDo: add support for different charsets - right now, only ASCII is supported!
	//	To achieve this, we should just translate everything into UTF-8 here

	last = c;
}


status_t
Text::SetTo(const char *text)
{
	return fText.SetTo(text) != NULL ? B_OK : B_NO_MEMORY;
}


const char *
Text::String() const
{
	return fText.String();
}


uint32
Text::Length() const
{
	return fText.Length();
}


//	#pragma mark -


Command::Command()
	:
	fName(NULL),
	fHasOption(false),
	fOption(-1)
{
}


Command::~Command()
{
}


void
Command::Parse(char first, BDataIO &stream, char &last) throw (status_t)
{
	if (first == '\0')
		first = read_char(stream);

	if (first != '\\')
		throw B_BAD_TYPE;

	// get name
	char name[kCommandLength];
	size_t length = 0;
	char c;
	while (isalpha(c = read_char(stream))) {
		name[length++] = c;
		if (length >= kCommandLength - 1)
			throw B_BAD_TYPE;
	}

	if (length == 0) {
		if (c == '\n' || c == '\r') {
			// we're a hard return
			fName.SetTo("par");
		} else
			fName.SetTo(c, 1);

		// read over character
		c = read_char(stream);
	} else
		fName.SetTo(name, length);

	// parse numeric option

	if (c == '-')
		c = read_char(stream);

	last = c;

	if (isdigit(c))
		SetOption(parse_integer(c, stream, last));

	// a space delimiter is eaten up by the command
	if (isspace(last))
		last = read_char(stream);
}


status_t
Command::SetName(const char *name)
{
	return fName.SetTo(name) != NULL ? B_OK : B_NO_MEMORY;
}


const char *
Command::Name()
{
	return fName.String();
}


void
Command::UnsetOption()
{
	fHasOption = false;
	fOption = -1;
}


void
Command::SetOption(int32 option)
{
	fOption = option;
	fHasOption = true;
}


bool
Command::HasOption() const
{
	return fHasOption;
}


int32
Command::Option() const
{
	return fOption;
}


//	#pragma mark -


Iterator::Iterator(Element &start, group_destination destination)
{
	SetTo(start, destination);
}


void
Iterator::SetTo(Element &start, group_destination destination)
{
	fStart = &start;
	fDestination = destination;

	Rewind();
}


void
Iterator::Rewind()
{
	fStack.MakeEmpty();
	fStack.Push(fStart);
}


bool
Iterator::HasNext() const
{
	return !fStack.IsEmpty();
}


Element *
Iterator::Next()
{
	Element *element;

	if (!fStack.Pop(&element))
		return NULL;

	Group *group = dynamic_cast<Group *>(element);
	if (group != NULL
		&& (fDestination == ALL_DESTINATIONS
			|| fDestination == group->Destination())) {
		// put this group's children on the stack in
		// reverse order, so that we iterate over
		// the tree in in-order

		for (int32 i = group->CountElements(); i-- > 0;) {
			fStack.Push(group->ElementAt(i));
		}
	}

	return element;
}