/*
 * Copyright 2014 Google Inc. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "tango-gl/util.h"
#include <rtabmap/utilite/ULogger.h>

namespace tango_gl {

namespace {
int NormalizedColorCameraRotation(int camera_rotation) {
  int camera_n = 0;
  switch (camera_rotation) {
    case 90:
      camera_n = 1;
      break;
    case 180:
      camera_n = 2;
      break;
    case 270:
      camera_n = 3;
      break;
    default:
      camera_n = 0;
      break;
  }
  return camera_n;
}
}  // annonymous namespace

void util::CheckGlError(const char* operation) {
  for (GLint error = glGetError(); error; error = glGetError()) {
    LOGE("after %s() glError (0x%x)\n", operation, error);
  }
}

// Convenience function used in CreateProgram below.
static GLuint LoadShader(GLenum shader_type, const char* shader_source) {
  GLuint shader = glCreateShader(shader_type);
  if (shader) {
    glShaderSource(shader, 1, &shader_source, NULL);
    glCompileShader(shader);
    GLint compiled = 0;
    glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
    if (!compiled) {
      GLint info_len = 0;
      glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &info_len);
      if (info_len) {
        char* buf = (char*) malloc(info_len);
        if (buf) {
          glGetShaderInfoLog(shader, info_len, NULL, buf);
          LOGE("Could not compile shader %d:\n%s\n", shader_type, buf);
          free(buf);
        }
        glDeleteShader(shader);
        shader = 0;
      }
    }
  }
  return shader;
}

GLuint util::CreateProgram(const char* vertex_source,
                             const char* fragment_source) {
  GLuint vertexShader = LoadShader(GL_VERTEX_SHADER, vertex_source);
  if (!vertexShader) {
    return 0;
  }

  GLuint fragment_shader = LoadShader(GL_FRAGMENT_SHADER, fragment_source);
  if (!fragment_shader) {
    return 0;
  }

  GLuint program = glCreateProgram();
  if (program) {
    glAttachShader(program, vertexShader);
    CheckGlError("glAttachShader");
    glAttachShader(program, fragment_shader);
    CheckGlError("glAttachShader");
    glLinkProgram(program);
    GLint link_status = GL_FALSE;
    glGetProgramiv(program, GL_LINK_STATUS, &link_status);
    if (link_status != GL_TRUE) {
      GLint buf_length = 0;
      glGetProgramiv(program, GL_INFO_LOG_LENGTH, &buf_length);
      if (buf_length) {
        char* buf = (char*) malloc(buf_length);
        if (buf) {
          glGetProgramInfoLog(program, buf_length, NULL, buf);
          LOGE("Could not link program:\n%s\n", buf);
          free(buf);
        }
      }
      glDeleteProgram(program);
      program = 0;
    }
  }
  CheckGlError("CreateProgram");
  return program;
}

void util::DecomposeMatrix (const glm::mat4& transform_mat,
                              glm::vec3& translation,
                              glm::quat& rotation,
                              glm::vec3& scale) {
  float scale_x = glm::length( glm::vec3( transform_mat[0][0], transform_mat[1][0], transform_mat[2][0] ) );
  float scale_y = glm::length( glm::vec3( transform_mat[0][1], transform_mat[1][1], transform_mat[2][1] ) );
  float scale_z = glm::length( glm::vec3( transform_mat[0][2], transform_mat[1][2], transform_mat[2][2] ) );


  float determinant = glm::determinant( transform_mat );
  if( determinant < 0.0 )
    scale_x = -scale_x;

  translation.x = transform_mat[3][0];
  translation.y = transform_mat[3][1];
  translation.z = transform_mat[3][2];

  float inverse_scale_x = 1.0 / scale_x;
  float inverse_scale_y = 1.0 / scale_y;
  float inverse_scale_z = 1.0 / scale_z;

  glm::mat4 transform_unscaled = transform_mat;

  transform_unscaled[0][0] *= inverse_scale_x;
  transform_unscaled[1][0] *= inverse_scale_x;
  transform_unscaled[2][0] *= inverse_scale_x;

  transform_unscaled[0][1] *= inverse_scale_y;
  transform_unscaled[1][1] *= inverse_scale_y;
  transform_unscaled[2][1] *= inverse_scale_y;

  transform_unscaled[0][2] *= inverse_scale_z;
  transform_unscaled[1][2] *= inverse_scale_z;
  transform_unscaled[2][2] *= inverse_scale_z;

  rotation = glm::quat_cast( transform_mat );

  scale.x = scale_x;
  scale.y = scale_y;
  scale.z = scale_z;
}

glm::vec3 util::GetColumnFromMatrix(const glm::mat4& mat, const int col) {
  return glm::vec3(mat[col][0], mat[col][1], mat[col][2]);
}

glm::vec3 util::GetTranslationFromMatrix(const glm::mat4& mat) {
  return glm::vec3(mat[3][0], mat[3][1], mat[3][2]);
}

float util::Clamp(float value, float min, float max) {
  return value < min ? min : (value > max ? max : value);
}

// Print out a column major matrix.
void util::PrintMatrix(const glm::mat4& matrix) {
  int i;
  for (i = 0; i < 4; i++) {
    LOGI("[ %f, %f, %f, %f ]", matrix[0][i], matrix[1][i], matrix[2][i],
         matrix[3][i]);
  }
  LOGI(" ");
}

void util::PrintVector(const glm::vec3& vector) {
  LOGI("[ %f, %f, %f ]", vector[0], vector[1], vector[2]);
  LOGI(" ");
}

void util::PrintQuaternion(const glm::quat& quat) {
  LOGI("[ %f, %f, %f, %f ]", quat[0], quat[1], quat[2], quat[3]);
  LOGI(" ");
}

glm::vec3 util::LerpVector(const glm::vec3& x, const glm::vec3& y, float a) {
  return x * (1.0f - a) + y * a;
}

float util::DistanceSquared(const glm::vec3& v1, const glm::vec3& v2) {
  glm::vec3 delta = v2 - v1;
  return glm::dot(delta, delta);
}

bool util::SegmentAABBIntersect(const glm::vec3& aabb_min,
                            const glm::vec3& aabb_max,
                            const glm::vec3& start,
                            const glm::vec3& end) {
  float tmin, tmax, tymin, tymax, tzmin, tzmax;
  glm::vec3 direction = end - start;
  if (direction.x >= 0) {
    tmin = (aabb_min.x - start.x) / direction.x;
    tmax = (aabb_max.x - start.x) / direction.x;
  } else {
    tmin = (aabb_max.x - start.x) / direction.x;
    tmax = (aabb_min.x - start.x) / direction.x;
  }
  if (direction.y >= 0) {
    tymin = (aabb_min.y - start.y) / direction.y;
    tymax = (aabb_max.y - start.y) / direction.y;
  } else {
    tymin = (aabb_max.y - start.y) / direction.y;
    tymax = (aabb_min.y - start.y) / direction.y;
  }
  if ((tmin > tymax) || (tymin > tmax)) return false;

  if (tymin > tmin) tmin = tymin;
  if (tymax < tmax) tmax = tymax;
  if (direction.z >= 0) {
    tzmin = (aabb_min.z - start.z) / direction.z;
    tzmax = (aabb_max.z - start.z) / direction.z;
  } else {
    tzmin = (aabb_max.z - start.z) / direction.z;
    tzmax = (aabb_min.z - start.z) / direction.z;
  }
  if ((tmin > tzmax) || (tzmin > tmax)) return false;

  if (tzmin > tmin) tmin = tzmin;
  if (tzmax < tmax) tmax = tzmax;
  // Use the full length of the segment.
  return ((tmin < 1.0f) && (tmax > 0));
}

glm::vec3 util::ApplyTransform(const glm::mat4& mat, const glm::vec3& vec) {
  return glm::vec3(mat * glm::vec4(vec, 1.0f));
}

}  // namespace tango_gl