// Copyright (c) 2005-2006, Rodrigo Braz Monteiro, Fredrik Mellbin
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//   * Redistributions of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//   * Redistributions in binary form must reproduce the above copyright notice,
//     this list of conditions and the following disclaimer in the documentation
//     and/or other materials provided with the distribution.
//   * Neither the name of the Aegisub Group nor the names of its contributors
//     may be used to endorse or promote products derived from this software
//     without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//
// -----------------------------------------------------------------------------
//
// AEGISUB
//
// Website: http://aegisub.cellosoft.com
// Contact: mailto:zeratul@cellosoft.com
//


///////////
// Headers
#include "vfr.h"
#include "utils.h"
#include <wx/filename.h>
#include <fstream>
#include <algorithm>

/////////////////////
// V2 Clear function
void FrameRate::Clear () {
	Frame.clear();
}


////////////////
// V2 Add frame
void FrameRate::AddFrame(int ms) {
	Frame.push_back(ms);
}


//////////////////
// V2 Get Average
void FrameRate::CalcAverage() {
	double last = 0.0;
	int frames = 0;
	for (std::vector<int>::iterator cur=Frame.begin();cur!=Frame.end();cur++) {
		last = *cur;
		frames++;
	}

	AverageFrameRate = double(frames)*1000.0/last;
}


//////////////////////// FrameRate //////////////////////
///////////////
// Constructor
FrameRate::FrameRate() {
	Unload();
}


//////////////
// Destructor
FrameRate::~FrameRate() {
	Clear();
}


/////////////////////////////
// Gets frame number at time
int FrameRate::GetFrameAtTime(int ms) {
	if (!loaded) return -1;

	ms = MAX(ms,0); //fix me, unsafe for CorrectFrame... for frame 0?

	if (FrameRateType == CFR) {
		return floor((double(ms)/1000.0) * AverageFrameRate);
	}
	else if (FrameRateType == VFR) {
		if (ms < floor(last_time)) {
			// Binary search
			size_t start = 0;
			size_t end = last_frame;
			size_t cur;
			bool largerEqual;
			while (start <= end) {
				cur = (start+end)>>1;
				largerEqual = Frame[cur] >= ms;

				// Found
				if (largerEqual && (cur == 0 || Frame[cur-1] < ms))
					return cur;
				
				// Not found
				if (largerEqual) end = cur-1;
				else start = cur+1;
			}
		} else if (assumefps != 0) {
			return last_frame + floor((ms-last_time) * assumefps / 1000);
		}
	}
	return -1;
}


//////////////////////
// Gets time at frame
int FrameRate::GetTimeAtFrame(int frame) {
	if (!loaded) return -1;

	wxASSERT(frame >= 0);

	if (FrameRateType == CFR) {
		return floor(double(frame) / AverageFrameRate * 1000);
	} else if (FrameRateType == VFR) {
		if (frame < last_frame)
			return Frame.at(frame);
		else if (assumefps != 0)
			return floor(last_time + (frame-last_frame+1) / assumefps * 1000);
	}
	return -1;
}


//////////////////
// Loads VFR file
void FrameRate::Load(wxString filename) {
	using namespace std;
	
	// Check if file exists
	wxFileName filetest(filename);
	if (!filetest.FileExists()) throw _T("File not found.");

	// Open file
	ifstream file;
	file.open(filename.mb_str(wxConvLocal));
	if (!file.is_open()) throw _T("Could not open file.");

	//fix me, will b0rk if loading the file fails
	Unload();

	// Read header
	char buffer[65536];
	file.getline(buffer,65536);
	wxString header(buffer,wxConvUTF8);

	// V1, code converted from avcvfr9
	if (header == _T("# timecode format v1")) {
		//locate the default fps line
		
		while (!file.eof()) {
			file.getline(buffer,65536);
			wxString curLine(buffer,wxConvUTF8);

			//skip empty lines and comments
			if (curLine == _T("") || curLine.Left(1) == _T("#"))
				continue;
			//fix me? should be case insensitive comparison
			else if (curLine.Left(7) != _T("Assume "))
				throw _T("Encountered data before 'Assume <fps>' line");
			else {
				curLine.Mid(6).ToDouble(&assumefps);
				break;
			}
		}

		//read and expand all timecodes to v2
		wxString curline;

		double currenttime = 0;
		int lposition = -1;

		long lstart;
		long lend;
		double lfps;

		while (!file.eof()) {
			file.getline(buffer,65536);
			wxString curLine(buffer,wxConvUTF8);

			//skip empty lines and comments
			if (curLine == _T("") || curLine.Left(1) == _T("#"))
				continue;
			
			wxString tmp = curLine.AfterFirst(_T(','));
			wxString temp = curLine.BeforeFirst(_T(','));
			temp.ToLong(&lstart);
			temp = tmp.BeforeLast(_T(','));
			temp.ToLong(&lend);
			temp = tmp.AfterLast(_T(','));
			temp.ToDouble(&lfps);

			for (int i = 0; i <= lstart - lposition - 2; i++)
				AddFrame(floor(currenttime+(i*1000) / assumefps));

			currenttime += ((lstart - lposition - 1)*1000) / assumefps;

			for (int i = 0; i <= lend - lstart; i++)
				AddFrame(floor(currenttime+(i*1000) / lfps));

			currenttime += ((lend - lstart + 1)*1000) / lfps;

			lposition = lend;
		}

		last_time = currenttime;
		last_frame = Frame.size();
	}

	// V2
	else if (header == _T("# timecode format v2")) {
		// Assigns new VFR file
		FrameRateType = VFR;

		long lftime = -1;
		long cftime = 0;
		last_frame = 0;

		// Reads body
		while (!file.eof()) {
			file.getline (buffer,65536);
			wxString curLine(buffer,wxConvUTF8);

			//skip empty lines and comments
			if (curLine == _T("") || curLine.Left(1) == _T("#"))
				continue;

			wxString tmp = curLine.BeforeFirst(_T('.'));
			tmp.ToLong(&cftime);
			wxASSERT(lftime < cftime);
			AddFrame(cftime);
			lftime = cftime;
		}

		last_time = cftime;
		last_frame = Frame.size();

	}

	// Unknown
	else {
		file.close();
		Unload();
		throw _T("Unknown file format.");
	}

	// Run test
	bool doTest = false;
	if (doTest) {
		int fail = 0;
		int res;
		for (int i=0;i<1000;i++) {
			res = GetFrameAtTime(GetTimeAtFrame(i));
			if (res != i) {
				wxLogMessage(wxString::Format(_T("Expected %i but got %i (%i)"),i,res,GetTimeAtFrame(i)));
				fail++;
			}
		}
		if (fail) wxLogMessage(wxString::Format(_T("Failed %i times"),fail));
		else wxLogMessage(_T("VFR passes test"));
	}

	// Close file
	file.close();
	loaded = true;
	vfrFile = filename;
	FrameRateType = VFR;
	CalcAverage();
}


//////////
// Unload
void FrameRate::Unload () {
	FrameRateType = NONE;
	AverageFrameRate = 0;
	assumefps = 0;
	last_time = 0;
	last_frame = 0;
	Clear();
	loaded = false;
	vfrFile = _T("");
}


///////////////
// Sets to CFR
void FrameRate::SetCFR(double fps,bool ifunset) {
	if (loaded && ifunset) return;

	Unload();
	loaded = true;
	vfrFile = _T("");
	FrameRateType = CFR;
	AverageFrameRate = fps;
}

/////////////////////////////
// Get correct frame at time
// returns the adjusted time for end frames when start=false
// otherwise for start frames
int FrameRate::CorrectFrameAtTime(int ms,bool start) {
	int frame;

	// CFR
	if (FrameRateType == CFR) {
		int delta = 0;
		if (start) delta = 1;
		frame = GetFrameAtTime(ms-delta)+delta;
		int time = GetTimeAtFrame(frame);
		if (start && time < ms) frame++;
		if (!start && time > ms) frame--;
	}

	// VFR
	else {
		frame = GetFrameAtTime(ms);
		if (!start) frame--;
	}

	return frame;
}


/////////////////////////////
// Get correct time at frame
// compensates and returns an end time when start=false
int FrameRate::CorrectTimeAtFrame(int frame,bool start) {
	if (start)
		return GetTimeAtFrame(frame);
	else
		return GetTimeAtFrame(frame+1);
}


///////////
// Globals
FrameRate VFR_Output;
FrameRate VFR_Input;