#pragma once

#ifndef TSPECTRUM_INCLUDED
#define TSPECTRUM_INCLUDED

#include "tpixelutils.h"
#include "tutil.h"

#undef DVAPI
#undef DVVAR
#ifdef TCOLOR_EXPORTS
#define DVAPI DV_EXPORT_API
#define DVVAR DV_EXPORT_VAR
#else
#define DVAPI DV_IMPORT_API
#define DVVAR DV_IMPORT_VAR
#endif

#ifdef _WIN32
#pragma warning(disable : 4251)
#endif

//===================================================================

template <class T>
class DVAPI TSpectrumT
{
public:
	typedef std::pair<double, T> ColorKey;
	typedef ColorKey Key;

private:
	typedef std::vector<ColorKey> KeyTable;
	KeyTable m_keys, m_sortedKeys;
	typedef std::pair<T, T> Pair; // premultiplied/not premultiplied
	std::vector<Pair> m_samples;

	inline T getActualValue(double s)
	{
		assert(!m_sortedKeys.empty());
		typename std::vector<ColorKey>::const_iterator b;
		b = std::lower_bound(m_sortedKeys.begin(), m_sortedKeys.end(), ColorKey(s, T()));
		if (b == m_sortedKeys.end())
			return m_sortedKeys.rbegin()->second;
		else if (b == m_sortedKeys.begin() || areAlmostEqual(b->first, s))
			return b->second;
		else {
			typename KeyTable::const_iterator a = b;
			a--;
			assert(a->first < s && s <= b->first);
			double f = (s - a->first) / (b->first - a->first);
			return blend(a->second, b->second, f);
		}
	}

	void update()
	{
		assert(!m_keys.empty());
		m_sortedKeys = m_keys;
		std::sort(m_sortedKeys.begin(), m_sortedKeys.end());
		if (m_samples.empty())
			m_samples.resize(100);
		int n = m_samples.size();
		for (int i = 0; i < n; i++) {
			T v = getActualValue((double)i / (double)(n - 1));
			m_samples[i].second = v;
			m_samples[i].first = premultiply(v);
		}
	}

public:
	TSpectrumT()
		: m_keys(), m_sortedKeys(), m_samples() {}

	TSpectrumT(const TSpectrumT<T> &s)
		: m_keys(s.m_keys), m_sortedKeys(s.m_sortedKeys), m_samples(s.m_samples) {}

	TSpectrumT(int keyCount, ColorKey keys[], int sampleCount = 100)
		: m_keys(keys, keys + keyCount)
	{
		m_samples.resize(sampleCount);
		update();
	}

	/*SpectrumT(std::map<double, T> &keys, int sampleCount=100)
  {
    m_keys = keys;
    updateTable(sampleCount);
  }
*/

	TSpectrumT(const T &a, const T &b, int sampleCount = 100)
	{
		m_keys.push_back(ColorKey(0, a));
		m_keys.push_back(ColorKey(1, b));
		m_samples.resize(sampleCount);
		update();
	}

	bool operator==(const TSpectrumT<T> &s) const
	{
		if (m_keys.size() != s.m_keys.size())
			return false;
		typename KeyTable::const_iterator i0, i1;
		for (i0 = m_keys.begin(),
			i1 = s.m_keys.begin();
			 i0 != m_keys.end();
			 ++i0, ++i1) {
			assert(i1 != s.m_keys.end());
			if (i0->first != i1->first)
				return false;
			if (i0->second != i1->second)
				return false;
		}
		return true;
	}

	bool operator!=(const TSpectrumT<T> &s) const
	{
		return !operator==(s);
	}

	T getValue(double s) const // non premoltiplicati
	{
		assert(!m_keys.empty());
		int m = m_samples.size();
		assert(m > 1);
		if (s <= 0)
			return m_samples.front().second;
		else if (s >= 1)
			return m_samples.back().second;
		s = s * (m - 1);
		int i = tfloor(s);
		assert(0 <= i && i < m - 1);
		s -= i;
		assert(0 <= s && s < 1);
		T a = m_samples[i].second;
		T b = m_samples[i + 1].second;
		return blend<T>(a, b, s);
	}

	T getPremultipliedValue(double s) const // non premoltiplicati
	{
		assert(!m_keys.empty());
		int m = m_samples.size();
		assert(m > 1);
		if (s <= 0)
			return m_samples.front().first;
		else if (s >= 1)
			return m_samples.back().first;
		s = s * (m - 1);
		int i = tfloor(s);
		assert(0 <= i && i < m - 1);
		s -= i;
		assert(0 <= s && s < 1);
		T a = m_samples[i].first;
		T b = m_samples[i + 1].first;
		return blend<T>(a, b, s);
	}

	int getKeyCount() const
	{
		return m_keys.size();
	}

	Key getKey(int index) const
	{
		assert(0 <= index && index < getKeyCount());
		return m_keys[index];
	}

	void setKey(int index, const Key &key)
	{
		assert(0 <= index && index < getKeyCount());
		assert(0 <= key.first && key.first <= 1);
		m_keys[index] = key;
		update();
	}

	void addKey(const Key &key)
	{
		m_keys.push_back(key);
		update();
	}

	void removeKey(int index)
	{
		if (m_keys.size() <= 1)
			return;
		assert(0 <= index && index < getKeyCount());
		m_keys.erase(m_keys.begin() + index);
		update();
	}
};

#ifdef _WIN32
template class DVAPI TSpectrumT<TPixel32>;
template class DVAPI TSpectrumT<TPixel64>;
#endif

typedef TSpectrumT<TPixel32> TSpectrum;
typedef TSpectrumT<TPixel64> TSpectrum64;

#ifdef _WIN32
#pragma warning(default : 4251)
#endif

#endif