/**
 * \file
 * \brief Source code for the Keyframe class
 * \author Copyright (c) 2011 Jonathan Thomas
 */

#include "../include/KeyFrame.h"

using namespace std;
using namespace openshot;

/// Because points can be added in any order, we need to reorder them
/// in ascending order based on the point.co.X value.  This simplifies
/// processing the curve, due to all the points going from left to right.
void Keyframe::ReorderPoints() {
	// Loop through all coordinates, and sort them by the X attribute
	for (int x = 0; x < Points.size(); x++) {
		int compare_index = x;
		int smallest_index = x;

		for (int compare_index = x + 1; compare_index < Points.size(); compare_index++) {
			if (Points[compare_index].co.X < Points[smallest_index].co.X) {
				smallest_index = compare_index;
			}
		}

		// swap items
		if (smallest_index != compare_index) {
			cout << "swap item " << Points[compare_index].co.X << " with "
					<< Points[smallest_index].co.X << endl;
			swap(Points[compare_index], Points[smallest_index]);
		}
	}
}

// Constructor which sets the default point & coordinate at X=0
Keyframe::Keyframe(float value) : Auto_Handle_Percentage(0.4f) {
	// Init the factorial table, needed by bezier curves
	CreateFactorialTable();

	// Add initial point
	AddPoint(Point(value));
}

/// Keyframe constructor
Keyframe::Keyframe() : Auto_Handle_Percentage(0.4f) {
	// Init the factorial table, needed by bezier curves
	CreateFactorialTable();
}

/// Add a new point on the key-frame.  Each point has a primary coordinate,
/// a left handle, and a right handle.
void Keyframe::AddPoint(Point p) {
	// Add point at correct spot
	Points.push_back(p);

	// Sort / Re-order points based on X coordinate
	ReorderPoints();

	// Set Handles (used for smooth curves).
	SetHandles(p);

	// Process all points in Key-frame
	Process();
}

/// Set the handles, used for smooth curves.  The handles are based
/// on the surrounding points.
void Keyframe::SetHandles(Point current)
{
	// Lookup the index of this point
	int index = FindIndex(current);
	Point *Current_Point = &Points[index];

	// Find the previous point and next points (if any)
	Point *Previous_Point = NULL;
	Point *Next_Point = NULL;
	float Previous_X_diff = 0.0f;
	float Next_X_diff = 0.0f;

	// If not the 1st point
	if (index > 0)
		Previous_Point = &Points[index - 1];

	// If not the last point
	if (index < (Points.size() - 1))
		Next_Point = &Points[index + 1];

	// Update the previous point's right handle
	if (Previous_Point)
		Previous_X_diff = (Current_Point->co.X - Previous_Point->co.X) * Auto_Handle_Percentage; // Use the keyframe handle percentage to size the handle
	if (Previous_Point && Previous_Point->handle_type == AUTO)
		Previous_Point->handle_right.X = Previous_Point->co.X + Previous_X_diff;
	// Update the current point's left handle
	if (Current_Point->handle_type == AUTO)
		Current_Point->handle_left.X = Current_Point->co.X - Previous_X_diff;

	// Update the next point's left handle
	if (Next_Point)
		Next_X_diff = (Next_Point->co.X - Current_Point->co.X) * Auto_Handle_Percentage; // Use the keyframe handle percentage to size the handle
	if (Next_Point && Next_Point->handle_type == AUTO)
		Next_Point->handle_left.X = Next_Point->co.X - Next_X_diff;
	// Update the next point's right handle
	if (Current_Point->handle_type == AUTO)
		Current_Point->handle_right.X = Current_Point->co.X + Next_X_diff;
}

// Get the index of a point by matching a coordinate
int Keyframe::FindIndex(Point p) throw(OutOfBoundsPoint) {
	// loop through points, and find a matching coordinate
	for (int x = 0; x < Points.size(); x++) {
		// Get each point
		Point existing_point = Points[x];

		// find a match
		if (p.co.X == existing_point.co.X && p.co.Y == existing_point.co.Y) {
			// Remove the matching point, and break out of loop
			return x;
		}
	}

	// no matching point found
	throw OutOfBoundsPoint("Invalid point requested", -1, Points.size());
}

// Get the value at a specific index
Coordinate Keyframe::GetValue(int index)
{
	// Is index a valid point?
	if (index >= 0 && index < Values.size())
		// Return value
		return Values[index];
	else if (index < 0 && Values.size() > 0)
		// Return the minimum value
		return Coordinate(index, Values[0].Y);
	else if (index >= Values.size() && Values.size() > 0)
		// return the maximum value
		return Coordinate(index, Values[Values.size() - 1].Y);
	else
		// return a blank coordinate (0,0)
		return Coordinate(0,0);
}

// Get a point at a specific index
Point& Keyframe::GetPoint(int index) throw(OutOfBoundsPoint) {
	// Is index a valid point?
	if (index >= 0 && index < Points.size())
		return Points[index];
	else
		// Invalid index
		throw OutOfBoundsPoint("Invalid point requested", index, Points.size());
}

// Remove a point by matching a coordinate
void Keyframe::RemovePoint(Point p) throw(OutOfBoundsPoint) {
	// loop through points, and find a matching coordinate
	for (int x = 0; x < Points.size(); x++) {
		// Get each point
		Point existing_point = Points[x];

		// find a match
		if (p.co.X == existing_point.co.X && p.co.Y == existing_point.co.Y) {
			// Remove the matching point, and break out of loop
			Points.erase(Points.begin() + x);

			// Process points
			Process();

			break;
		}
	}

	// no matching point found
	throw OutOfBoundsPoint("Invalid point requested", -1, Points.size());
}

// Remove a point by index
void Keyframe::RemovePoint(int index) throw(OutOfBoundsPoint) {
	// Is index a valid point?
	if (index >= 0 && index < Points.size())
	{
		// Remove a specific point by index
		Points.erase(Points.begin() + index);

		// Process points
		Process();
	}
	else
		// Invalid index
		throw OutOfBoundsPoint("Invalid point requested", index, Points.size());
}

void Keyframe::UpdatePoint(int index, Point p) {
	// Remove matching point
	RemovePoint(index);

	// Add new point
	AddPoint(p);

	// Reorder points
	ReorderPoints();

	// Process points
	Process();
}

void Keyframe::PrintPoints() {
	int x = 0;
	for (vector<Point>::iterator it = Points.begin(); it != Points.end(); it++) {
		cout << it->co.X << "\t" << it->co.Y << endl;
		x++;
	}
}

void Keyframe::PrintValues() {
	cout << " PRINT ALL VALUES " << endl;

	for (int x = 0; x < Values.size(); x++) {
		Coordinate c = Values[x];
		cout << c.X << "\t" << c.Y << endl;
	}
}

void Keyframe::Process() {
	// do not process if no points are found
	if (Points.size() == 0)
		return;

	// Clear all values
	Values.clear();

	// fill in all values between 0 and 1st point's co.X
	Point p1 = Points[0];
	for (int x = 0; x < p1.co.X; x++)
		Values.push_back(Coordinate(Values.size(), p1.co.Y));

	// Loop through each pair of points (1 less than the max points).  Each
	// pair of points is used to process a segment of the keyframe.
	Point p2(0, 0);
	for (int x = 0; x < Points.size() - 1; x++) {
		p1 = Points[x];
		p2 = Points[x + 1];

		// process segment p1,p2
		ProcessSegment(x, p1, p2);
	}
}

void Keyframe::ProcessSegment(int Segment, Point p1, Point p2) {
	// Determine the number of values for this segment
	int number_of_values = round(p2.co.X) - round(p1.co.X);

	// Exit function if no values
	if (number_of_values == 0)
		return;

	// Based on the interpolation mode, fill the "values" vector with the coordinates
	// for this segment
	switch (p2.interpolation) {

	// Calculate the "values" for this segment in with a LINEAR equation, effectively
	// creating a straight line with coordinates.
	case LINEAR: {
		// Get the difference in value
		float current_value = p1.co.Y;
		float value_difference = p2.co.Y - p1.co.Y;
		float value_increment = 0.0f;

		// Get the increment value, but take into account the
		// first segment has 1 extra value
		value_increment = value_difference / (float) (number_of_values);

		if (Segment == 0)
			// Add an extra value to the first segment
			number_of_values++;
		else
			// If not 1st segment, skip the first value
			current_value += value_increment;

		// Add each increment to the values vector
		for (int x = 0; x < number_of_values; x++) {
			// add value as a coordinate to the "values" vector
			Values.push_back(Coordinate(Values.size(), current_value));

			// increment value
			current_value += value_increment;
		}

		break;
	}

		// Calculate the "values" for this segment using a quadratic Bezier curve.  This creates a
		// smooth curve.
	case BEZIER: {

		// Always increase the number of points by 1 (need all possible points
		// to correctly calculate the curve).
		number_of_values++;
		number_of_values *= 4;	// We need a higher resolution curve (4X)

		vector<Coordinate> segment_coordinates;
		segment_coordinates.push_back(p1.co);
		segment_coordinates.push_back(p1.handle_right);
		segment_coordinates.push_back(p2.handle_left);
		segment_coordinates.push_back(p2.co);

		vector<Coordinate> raw_coordinates;
		int npts = segment_coordinates.size();
		int icount, jcount;
		double step, t;
		double last_x = -1; // small number init, to track the last used x

		// Calculate points on curve
		icount = 0;
		t = 0;

		step = (double) 1.0 / (number_of_values - 1);

		for (int i1 = 0; i1 < number_of_values; i1++) {
			if ((1.0 - t) < 5e-6)
				t = 1.0;

			jcount = 0;

			float new_x = 0.0f;
			float new_y = 0.0f;

			for (int i = 0; i < npts; i++) {
				Coordinate co = segment_coordinates[i];
				double basis = Bernstein(npts - 1, i, t);
				new_x += basis * co.X;
				new_y += basis * co.Y;
			}

			// Add new value to the vector
			Coordinate current_value(new_x, new_y);

			// Add all values for 1st segment
			raw_coordinates.push_back(current_value);

			// increment counters
			icount += 2;
			t += step;
		}

		// Loop through the raw coordinates, and map them correctly to frame numbers.  For example,
		// we can't have duplicate X values, since X represents our frame  numbers.
		int current_frame = p1.co.X;
		float current_value = p1.co.Y;
		for (int i = 0; i < raw_coordinates.size(); i++)
		{
			// Get the raw coordinate
			Coordinate raw = raw_coordinates[i];

			if (current_frame == round(raw.X))
				// get value of raw coordinate
				current_value = raw.Y;
			else
			{
				// Missing X values (use last known Y values)
				int number_of_missing = round(raw.X) - current_frame;
				for (int missing = 0; missing < number_of_missing; missing++)
				{
					// Add new value to the vector
					Coordinate new_coord(current_frame, current_value);

					if (Segment == 0 || Segment > 0 && current_frame > p1.co.X)
						// Add to "values" vector
						Values.push_back(new_coord);

					// Increment frame
					current_frame++;
				}

				// increment the current value
				current_value = raw.Y;
			}
		}

		// Add final coordinate
		Coordinate new_coord(current_frame, current_value);
		Values.push_back(new_coord);

		break;
	}

		// Calculate the "values" of this segment by maintaining the value of p1 until the
		// last point, and then make the value jump to p2.  This effectively just jumps
		// the value, instead of ramping up or down the value.
	case CONSTANT: {

		if (Segment == 0)
			// first segment has 1 extra value
			number_of_values++;

		// Add each increment to the values vector
		for (int x = 0; x < number_of_values; x++) {
			if (x < (number_of_values - 1)) {
				// Not the last value of this segment
				// add coordinate to "values"
				Values.push_back(Coordinate(Values.size(), p1.co.Y));
			} else {
				// This is the last value of this segment
				// add coordinate to "values"
				Values.push_back(Coordinate(Values.size(), p2.co.Y));
			}
		}
		break;
	}

	}
}

// Create lookup table for fast factorial calculation
void Keyframe::CreateFactorialTable() {
	// Only 4 lookups are needed, because we only support 4 coordinates per curve
	FactorialLookup[0] = 1.0;
	FactorialLookup[1] = 1.0;
	FactorialLookup[2] = 2.0;
	FactorialLookup[3] = 6.0;
}

// Get a factorial for a coordinate
double Keyframe::Factorial(int n) {
	assert(n >= 0 && n <= 3);
	return FactorialLookup[n]; /* returns the value n! as a SUMORealing point number */
}

// Calculate the factorial function for Bernstein basis
double Keyframe::Ni(int n, int i) {
	double ni;
	double a1 = Factorial(n);
	double a2 = Factorial(i);
	double a3 = Factorial(n - i);
	ni = a1 / (a2 * a3);
	return ni;
}

// Calculate Bernstein basis
double Keyframe::Bernstein(int n, int i, double t) {
	double basis;
	double ti; /* t^i */
	double tni; /* (1 - t)^i */

	/* Prevent problems with pow */
	if (t == 0.0 && i == 0)
		ti = 1.0;
	else
		ti = pow(t, i);

	if (n == i && t == 1.0)
		tni = 1.0;
	else
		tni = pow((1 - t), (n - i));

	// Bernstein basis
	basis = Ni(n, i) * ti * tni;
	return basis;
}