// Copyright (C) 2015 Jérôme Leclercq
// This file is part of the "Nazara Engine - Utility module"
// For conditions of distribution and use, see copyright notice in Config.hpp

#include <Nazara/Utility/Formats/MD5MeshParser.hpp>
#include <Nazara/Core/Error.hpp>
#include <Nazara/Math/Algorithm.hpp>
#include <Nazara/Utility/BufferMapper.hpp>
#include <Nazara/Utility/Config.hpp>
#include <Nazara/Utility/IndexIterator.hpp>
#include <Nazara/Utility/IndexMapper.hpp>
#include <Nazara/Utility/Mesh.hpp>
#include <Nazara/Utility/SkeletalMesh.hpp>
#include <Nazara/Utility/Skeleton.hpp>
#include <Nazara/Utility/StaticMesh.hpp>
#include <cstdio>
#include <cstring>
#include <limits>
#include <memory>
#include <Nazara/Utility/Debug.hpp>

namespace Nz
{
	MD5MeshParser::MD5MeshParser(Stream& stream) :
	m_stream(stream),
	m_keepLastLine(false),
	m_lineCount(0),
	m_meshIndex(0),
	m_streamFlags(stream.GetStreamOptions()) //< Saves stream flags
	{
		m_stream.EnableTextMode(true);
	}

	MD5MeshParser::~MD5MeshParser()
	{
		// Reset stream flags
		if ((m_streamFlags & StreamOption_Text) == 0)
			m_stream.EnableTextMode(false);
	}

	Ternary MD5MeshParser::Check()
	{
		if (Advance(false))
		{
			unsigned int version;
			if (std::sscanf(&m_currentLine[0], " MD5Version %u", &version) == 1)
			{
				if (version == 10)
					return Ternary_True;
			}
		}

		return Ternary_False;
	}

	const MD5MeshParser::Joint* MD5MeshParser::GetJoints() const
	{
		return m_joints.data();
	}

	std::size_t MD5MeshParser::GetJointCount() const
	{
		return m_joints.size();
	}

	const MD5MeshParser::Mesh* MD5MeshParser::GetMeshes() const
	{
		return m_meshes.data();
	}

	std::size_t MD5MeshParser::GetMeshCount() const
	{
		return m_meshes.size();
	}

	bool MD5MeshParser::Parse()
	{
		while (Advance(false))
		{
			switch (m_currentLine[0])
			{
				#if NAZARA_UTILITY_STRICT_RESOURCE_PARSING
				case 'M': // MD5Version
					if (m_currentLine.GetWord(0) != "MD5Version")
						UnrecognizedLine();
					break;

				case 'c': // commandline
					if (m_currentLine.GetWord(0) != "commandline")
						UnrecognizedLine();
					break;
				#endif

				case 'j': // joints
					#if NAZARA_UTILITY_STRICT_RESOURCE_PARSING
					if (!m_currentLine.StartsWith("joints {"))
					{
						UnrecognizedLine();
						break;
					}
					#endif

					if (!ParseJoints())
					{
						Error("Failed to parse joints");
						return false;
					}
					break;

				case 'm': // mesh
				{
					#if NAZARA_UTILITY_STRICT_RESOURCE_PARSING
					if (m_currentLine != "mesh {")
					{
						UnrecognizedLine();
						break;
					}
					#endif

					if (m_meshIndex >= m_meshes.size())
					{
						#if NAZARA_UTILITY_STRICT_RESOURCE_PARSING
						Warning("More meshes than registred");
						#endif

						m_meshes.push_back(Mesh());
					}

					if (!ParseMesh())
					{
						NazaraError("Failed to parse mesh");
						return false;
					}

					m_meshIndex++;
					break;
				}

				case 'n': // num[Frames/Joints]
				{
					unsigned int count;
					if (std::sscanf(&m_currentLine[0], "numJoints %u", &count) == 1)
					{
						#if NAZARA_UTILITY_STRICT_RESOURCE_PARSING
						if (!m_joints.empty())
							Warning("Joint count is already defined");
						#endif

						m_joints.resize(count);
					}
					else if (std::sscanf(&m_currentLine[0], "numMeshes %u", &count) == 1)
					{
						#if NAZARA_UTILITY_STRICT_RESOURCE_PARSING
						if (!m_meshes.empty())
							Warning("Mesh count is already defined");
						#endif

						m_meshes.resize(count);
					}
					#if NAZARA_UTILITY_STRICT_RESOURCE_PARSING
					else
						UnrecognizedLine();
					#endif
					break;
				}

				default:
					#if NAZARA_UTILITY_STRICT_RESOURCE_PARSING
					UnrecognizedLine();
					#endif
					break;
			}
		}

		return true;
	}

	bool MD5MeshParser::Advance(bool required)
	{
		if (!m_keepLastLine)
		{
			do
			{
				if (m_stream.EndOfStream())
				{
					if (required)
						Error("Incomplete MD5 file");

					return false;
				}

				m_lineCount++;

				m_currentLine = m_stream.ReadLine();
				m_currentLine = m_currentLine.SubStringTo("//"); // On ignore les commentaires
				m_currentLine.Simplify(); // Pour un traitement plus simple
				m_currentLine.Trim();
			}
			while (m_currentLine.IsEmpty());
		}
		else
			m_keepLastLine = false;

		return true;
	}

	void MD5MeshParser::Error(const String& message)
	{
		NazaraError(message + " at line #" + String::Number(m_lineCount));
	}

	bool MD5MeshParser::ParseJoints()
	{
		unsigned int jointCount = m_joints.size();
		if (jointCount == 0)
		{
			Error("Joint count is invalid or missing");
			return false;
		}

		for (unsigned int i = 0; i < jointCount; ++i)
		{
			if (!Advance())
				return false;

			unsigned int pos = m_currentLine.Find(' ');
			if (pos == String::npos)
			{
				UnrecognizedLine(true);
				return false;
			}

			if (pos >= 64)
			{
				NazaraError("Joint name is too long (>= 64 characters)");
				return false;
			}

			char name[64];
			if (std::sscanf(&m_currentLine[0], "%63s %d ( %f %f %f ) ( %f %f %f )", &name[0], &m_joints[i].parent,
																					&m_joints[i].bindPos.x, &m_joints[i].bindPos.y, &m_joints[i].bindPos.z,
																					&m_joints[i].bindOrient.x, &m_joints[i].bindOrient.y, &m_joints[i].bindOrient.z) != 8)
			{
				UnrecognizedLine(true);
				return false;
			}

			m_joints[i].name = name;
			m_joints[i].name.Trim('"');

			int parent = m_joints[i].parent;
			if (parent >= 0)
			{
				if (static_cast<unsigned int>(parent) >= jointCount)
				{
					Error("Joint's parent is out of bounds (" + String::Number(parent) + " >= " + String::Number(jointCount) + ')');
					return false;
				}
			}

			m_joints[i].bindOrient.ComputeW(); // On calcule la composante W
		}

		if (!Advance())
			return false;

		if (m_currentLine != '}')
		{
			#if NAZARA_UTILITY_STRICT_RESOURCE_PARSING
			Warning("Hierarchy braces closing not found");
			#endif

			// On tente de survivre à l'erreur
			m_keepLastLine = true;
		}

		return true;
	}

	bool MD5MeshParser::ParseMesh()
	{
		bool finished = false;
		while (!finished && Advance(false))
		{
			switch (m_currentLine[0])
			{
				case '}':
					finished = true;
					break;

				case 's': // shader
					#if NAZARA_UTILITY_STRICT_RESOURCE_PARSING
					if (!m_currentLine.StartsWith("shader "))
					{
						UnrecognizedLine();
						break;
					}
					#endif

					m_meshes[m_meshIndex].shader = m_currentLine.SubString(7);
					m_meshes[m_meshIndex].shader.Trim('"');
					break;

				case 'n': // num[tris/verts]
				{
					unsigned int count;
					if (std::sscanf(&m_currentLine[0], "numtris %u", &count) == 1)
					{
						m_meshes[m_meshIndex].triangles.resize(count);
						for (unsigned int i = 0; i < count; ++i)
						{
							if (!Advance())
								return false;

							Triangle& triangle = m_meshes[m_meshIndex].triangles[i];
							unsigned int index;
							if (std::sscanf(&m_currentLine[0], "tri %u %u %u %u", &index, &triangle.x, &triangle.y, &triangle.z) != 4)
							{
								UnrecognizedLine(true);
								return false;
							}

							if (index != i)
							{
								Error("Unexpected triangle index (expected " + String::Number(i) + ", got " + String::Number(index) + ')');
								return false;
							}
						}
					}
					else if (std::sscanf(&m_currentLine[0], "numverts %u", &count) == 1)
					{
						m_meshes[m_meshIndex].vertices.resize(count);
						for (unsigned int i = 0; i < count; ++i)
						{
							if (!Advance())
								return false;

							Vertex& vertex = m_meshes[m_meshIndex].vertices[i];
							unsigned int index;
							if (std::sscanf(&m_currentLine[0], "vert %u ( %f %f ) %u %u", &index, &vertex.uv.x, &vertex.uv.y, &vertex.startWeight, &vertex.weightCount) != 5)
							{
								UnrecognizedLine(true);
								return false;
							}

							if (index != i)
							{
								Error("Unexpected vertex index (expected " + String::Number(i) + ", got " + String::Number(index) + ')');
								return false;
							}
						}
					}
					else if (std::sscanf(&m_currentLine[0], "numweights %u", &count) == 1)
					{
						m_meshes[m_meshIndex].weights.resize(count);
						for (unsigned int i = 0; i < count; ++i)
						{
							if (!Advance())
								return false;

							Weight& weight = m_meshes[m_meshIndex].weights[i];
							unsigned int index;
							if (std::sscanf(&m_currentLine[0], "weight %u %u %f ( %f %f %f )", &index, &weight.joint, &weight.bias,
																							   &weight.pos.x, &weight.pos.y, &weight.pos.z) != 6)
							{
								UnrecognizedLine(true);
								return false;
							}

							if (index != i)
							{
								Error("Unexpected weight index (expected " + String::Number(i) + ", got " + String::Number(index) + ')');
								return false;
							}
						}
					}
					#if NAZARA_UTILITY_STRICT_RESOURCE_PARSING
					else
						UnrecognizedLine();
					#endif
					break;
				}

				default:
					#if NAZARA_UTILITY_STRICT_RESOURCE_PARSING
					UnrecognizedLine();
					#endif
					break;
			}
		}

		if (m_meshes[m_meshIndex].triangles.empty())
		{
			NazaraError("Mesh has no triangles");
			return false;
		}

		if (m_meshes[m_meshIndex].vertices.empty())
		{
			NazaraError("Mesh has no vertices");
			return false;
		}

		if (m_meshes[m_meshIndex].weights.empty())
		{
			NazaraError("Mesh has no weights");
			return false;
		}

		#if NAZARA_UTILITY_STRICT_RESOURCE_PARSING
		if (!finished)
			Warning("Mesh braces closing not found");
		#endif

		return true;
	}

	void MD5MeshParser::Warning(const String& message)
	{
		NazaraWarning(message + " at line #" + String::Number(m_lineCount));
	}

	void MD5MeshParser::UnrecognizedLine(bool error)
	{
		String message = "Unrecognized \"" + m_currentLine + '"';

		if (error)
			Error(message);
		else
			Warning(message);
}
}