/*
    Copyright (C) 2014-2020 Carl Hetherington <cth@carlh.net>

    This file is part of DCP-o-matic.

    DCP-o-matic is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    DCP-o-matic is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with DCP-o-matic.  If not, see <http://www.gnu.org/licenses/>.

*/


#include "cross.h"
#include "exceptions.h"
#include "string_text_file.h"
#include "string_text_file_content.h"
#include <dcp/file.h>
#include <sub/collect.h>
#include <sub/exceptions.h>
#include <sub/ssa_reader.h>
#include <sub/stl_binary_reader.h>
#include <sub/subrip_reader.h>
#include <sub/web_vtt_reader.h>
#include <unicode/ucsdet.h>
#include <unicode/ucnv.h>
#include <iostream>

#include "i18n.h"


using std::cout;
using std::shared_ptr;
using std::string;
using std::vector;
using boost::scoped_array;
using boost::optional;
using dcp::ArrayData;
using namespace dcpomatic;


StringTextFile::StringTextFile (shared_ptr<const StringTextFileContent> content)
{
	string ext = content->path(0).extension().string();
	transform (ext.begin(), ext.end(), ext.begin(), ::tolower);

	std::unique_ptr<sub::Reader> reader;

	if (ext == ".stl") {
		dcp::File f(content->path(0), "rb");
		if (!f) {
			throw OpenFileError (f.path(), errno, OpenFileError::READ);
		}
		try {
			reader.reset(new sub::STLBinaryReader(f.get()));
		} catch (...) {
			throw;
		}

	} else {
		/* Text-based file; sort out its character encoding before we try to parse it */

		ArrayData in (content->path (0));

		UErrorCode status = U_ZERO_ERROR;
		UCharsetDetector* detector = ucsdet_open (&status);
		ucsdet_setText (detector, reinterpret_cast<const char *>(in.data()), in.size(), &status);

		UCharsetMatch const * match = ucsdet_detect (detector, &status);
		char const * in_charset = ucsdet_getName (match, &status);

		UConverter* to_utf16 = ucnv_open (in_charset, &status);
		/* This is a guess; I think we should be able to encode any input in 4 times its input size */
		scoped_array<uint16_t> utf16 (new uint16_t[in.size() * 2]);
		int const utf16_len = ucnv_toUChars (
				to_utf16, reinterpret_cast<UChar*>(utf16.get()), in.size() * 2,
				reinterpret_cast<const char *>(in.data()), in.size(),
				&status
				);

		UConverter* to_utf8 = ucnv_open ("UTF-8", &status);
		/* Another guess */
		scoped_array<char> utf8 (new char[utf16_len * 2]);
		ucnv_fromUChars (to_utf8, utf8.get(), utf16_len * 2, reinterpret_cast<UChar*>(utf16.get()), utf16_len, &status);

		/* Fix OS X line endings */
		size_t utf8_len = strlen (utf8.get ());
		for (size_t i = 0; i < utf8_len; ++i) {
			if (utf8[i] == '\r' && ((i == utf8_len - 1) || utf8[i + 1] != '\n')) {
				utf8[i] = '\n';
			}
		}

		ucsdet_close (detector);
		ucnv_close (to_utf16);
		ucnv_close (to_utf8);

		if (ext == ".srt") {
			try {
				reader.reset(new sub::SubripReader(utf8.get()));
			} catch (sub::SubripError& subrip_error) {
				/* Sometimes files are have the .srt extension but are really WEBVTT... */
				try {
					reader.reset(new sub::WebVTTReader(utf8.get()));
				} catch (sub::WebVTTHeaderError&) {
					/* ...but in this case there isn't even a WebVTT error */
					throw subrip_error;
				}
			}
		} else if (ext == ".ssa" || ext == ".ass") {
			reader.reset(new sub::SSAReader(utf8.get()));
		} else if (ext == ".vtt") {
			reader.reset(new sub::WebVTTReader(utf8.get()));
		}
	}

	if (reader) {
		_subtitles = sub::collect<vector<sub::Subtitle>>(reader->subtitles());
	}
}

/** @return time of first subtitle, if there is one */
optional<ContentTime>
StringTextFile::first () const
{
	if (_subtitles.empty()) {
		return {};
	}

	return ContentTime::from_seconds(_subtitles[0].from.all_as_seconds());
}

ContentTime
StringTextFile::length () const
{
	if (_subtitles.empty ()) {
		return {};
	}

	return ContentTime::from_seconds (_subtitles.back().to.all_as_seconds ());
}