// Copyright (C) 2015 The Android Open Source Project
//
// 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.

@Doc("https://www.khronos.org/opengles/sdk/docs/man/xhtml/glBindBuffer.xml","OpenGL ES 2.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man3/html/glBindBuffer.xhtml","OpenGL ES 3.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man31/html/glBindBuffer.xhtml","OpenGL ES 3.1")
cmd void glBindBuffer(GLenum target, BufferId buffer) {
  minRequiredVersion(2, 0)
  switch (target) {
    case GL_ARRAY_BUFFER, GL_ELEMENT_ARRAY_BUFFER: {
      // version 2.0
    }
    case GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, GL_PIXEL_PACK_BUFFER, GL_PIXEL_UNPACK_BUFFER,
        GL_TRANSFORM_FEEDBACK_BUFFER, GL_UNIFORM_BUFFER: {
      minRequiredVersion(3, 0)
    }
    case GL_ATOMIC_COUNTER_BUFFER, GL_DISPATCH_INDIRECT_BUFFER, GL_DRAW_INDIRECT_BUFFER,
        GL_SHADER_STORAGE_BUFFER: {
      minRequiredVersion(3, 1)
    }
    default: {
      glErrorInvalidEnum(target)
    }
  }

  ctx := GetContext()
  if !(buffer in ctx.Instances.Buffers) {
    ctx.Instances.Buffers[buffer] = new!Buffer()
  }
  ctx.BoundBuffers[target] = buffer
}

@Doc("https://www.khronos.org/opengles/sdk/docs/man3/html/glBindBufferBase.xhtml","OpenGL ES 3.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man31/html/glBindBufferBase.xhtml","OpenGL ES 3.1")
cmd void glBindBufferBase(GLenum target, GLuint index, BufferId buffer) {
  minRequiredVersion(3, 0)
  switch (target) {
    case GL_TRANSFORM_FEEDBACK_BUFFER, GL_UNIFORM_BUFFER: {
      // version 3.0
    }
    case GL_ATOMIC_COUNTER_BUFFER, GL_SHADER_STORAGE_BUFFER: {
      minRequiredVersion(3, 1)
    }
    default: {
      glErrorInvalidEnum(target)
    }
  }

  // TODO
}

@Doc("https://www.khronos.org/opengles/sdk/docs/man3/html/glBindBufferRange.xhtml","OpenGL ES 3.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man31/html/glBindBufferRange.xhtml","OpenGL ES 3.1")
cmd void glBindBufferRange(GLenum     target,
                           GLuint     index,
                           BufferId   buffer,
                           GLintptr   offset,
                           GLsizeiptr size) {
  minRequiredVersion(3, 0)
  switch (target) {
    case GL_TRANSFORM_FEEDBACK_BUFFER, GL_UNIFORM_BUFFER: {
      // version 3.0
    }
    case GL_ATOMIC_COUNTER_BUFFER, GL_SHADER_STORAGE_BUFFER: {
      minRequiredVersion(3, 1)
    }
    default: {
      glErrorInvalidEnum(target)
    }
  }
  // TODO
}

@Doc("https://www.khronos.org/opengles/sdk/docs/man/xhtml/glBufferData.xml","OpenGL ES 2.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man3/html/glBufferData.xhtml","OpenGL ES 3.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man31/html/glBufferData.xhtml","OpenGL ES 3.1")
cmd void glBufferData(GLenum target, GLsizeiptr size, BufferDataPointer data, GLenum usage) {
  minRequiredVersion(2, 0)
  switch (target) {
    case GL_ARRAY_BUFFER, GL_ELEMENT_ARRAY_BUFFER: {
      // version 2.0
    }
    case GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, GL_PIXEL_PACK_BUFFER, GL_PIXEL_UNPACK_BUFFER,
        GL_TRANSFORM_FEEDBACK_BUFFER, GL_UNIFORM_BUFFER: {
      minRequiredVersion(3, 0)
    }
    case GL_ATOMIC_COUNTER_BUFFER, GL_DISPATCH_INDIRECT_BUFFER, GL_DRAW_INDIRECT_BUFFER,
        GL_SHADER_STORAGE_BUFFER: {
      minRequiredVersion(3, 1)
    }
    default: {
      glErrorInvalidEnum(target)
    }
  }
  switch (usage) {
    case GL_DYNAMIC_DRAW, GL_STATIC_DRAW, GL_STREAM_DRAW: {
      // version 2.0
    }
    case GL_DYNAMIC_COPY, GL_DYNAMIC_READ, GL_STATIC_COPY, GL_STATIC_READ, GL_STREAM_COPY,
        GL_STREAM_READ: {
      minRequiredVersion(3, 0)
    }
    default: {
      glErrorInvalidEnum(usage)
    }
  }

  ctx := GetContext()
  id := ctx.BoundBuffers[target]
  b := ctx.Instances.Buffers[id]
  b.Data = switch (data != null) {
    case true:  clone(as!u8*(data)[0:size])
    case false: make!u8(size)
  }
  b.Size = size
  b.Usage = usage
}

@Doc("https://www.khronos.org/opengles/sdk/docs/man/xhtml/glBufferSubData.xml","OpenGL ES 2.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man3/html/glBufferSubData.xhtml","OpenGL ES 3.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man31/html/glBufferSubData.xhtml","OpenGL ES 3.1")
cmd void glBufferSubData(GLenum target, GLintptr offset, GLsizeiptr size, BufferDataPointer data) {
  minRequiredVersion(2, 0)
  switch (target) {
    case GL_ARRAY_BUFFER, GL_ELEMENT_ARRAY_BUFFER: {
      // version 2.0
    }
    case GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, GL_PIXEL_PACK_BUFFER, GL_PIXEL_UNPACK_BUFFER,
        GL_TRANSFORM_FEEDBACK_BUFFER, GL_UNIFORM_BUFFER: {
      minRequiredVersion(3, 0)
    }
    case GL_ATOMIC_COUNTER_BUFFER, GL_DISPATCH_INDIRECT_BUFFER, GL_DRAW_INDIRECT_BUFFER,
        GL_SHADER_STORAGE_BUFFER: {
      minRequiredVersion(3, 1)
    }
    default: {
      glErrorInvalidEnum(target)
    }
  }

  read(data[0:size])
  // TODO: Assignment to subset
}

@Doc("https://www.khronos.org/opengles/sdk/docs/man3/html/glCopyBufferSubData.xhtml","OpenGL ES 3.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man31/html/glCopyBufferSubData.xhtml","OpenGL ES 3.1")
cmd void glCopyBufferSubData(GLenum     readTarget,
                             GLenum     writeTarget,
                             GLintptr   readOffset,
                             GLintptr   writeOffset,
                             GLsizeiptr size) {
  minRequiredVersion(3, 0)
  switch (readTarget) {
    case GL_ARRAY_BUFFER, GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, GL_ELEMENT_ARRAY_BUFFER,
        GL_PIXEL_PACK_BUFFER, GL_PIXEL_UNPACK_BUFFER, GL_TRANSFORM_FEEDBACK_BUFFER,
        GL_UNIFORM_BUFFER: {
      // version 3.0
    }
    default: {
      glErrorInvalidEnum(readTarget)
    }
  }
  switch (writeTarget) {
    case GL_ARRAY_BUFFER, GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, GL_ELEMENT_ARRAY_BUFFER,
        GL_PIXEL_PACK_BUFFER, GL_PIXEL_UNPACK_BUFFER, GL_TRANSFORM_FEEDBACK_BUFFER,
        GL_UNIFORM_BUFFER: {
      // version 3.0
    }
    default: {
      glErrorInvalidEnum(writeTarget)
    }
  }
  // TODO
}

@Doc("https://www.khronos.org/opengles/sdk/docs/man/xhtml/glDeleteBuffers.xml","OpenGL ES 2.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man3/html/glDeleteBuffers.xhtml","OpenGL ES 3.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man31/html/glDeleteBuffers.xhtml","OpenGL ES 3.1")
cmd void glDeleteBuffers(GLsizei count, const BufferId* buffers) {
  minRequiredVersion(2, 0)

  b := buffers[0:count]
  ctx := GetContext()
  for i in (0 .. count) {
    ctx.Instances.Buffers[b[i]] = null
  }
}

@Doc("https://www.khronos.org/opengles/sdk/docs/man/xhtml/glGenBuffers.xml","OpenGL ES 2.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man3/html/glGenBuffers.xhtml","OpenGL ES 3.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man31/html/glGenBuffers.xhtml","OpenGL ES 3.1")
cmd void glGenBuffers(GLsizei count, BufferId* buffers) {
  minRequiredVersion(2, 0)

  b := buffers[0:count]
  ctx := GetContext()
  for i in (0 .. count) {
    id := as!BufferId(?)
    ctx.Instances.Buffers[id] = new!Buffer()
    b[i] = id
  }
}

@Doc("https://www.khronos.org/opengles/sdk/docs/man3/html/glGetBufferParameter.xhtml","OpenGL ES 3.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man31/html/glGetBufferParameter.xhtml","OpenGL ES 3.1")
cmd void glGetBufferParameteri64v(GLenum target, GLenum pname, GLint64* params) {
  minRequiredVersion(3, 0)
  switch (target) {
    case GL_ARRAY_BUFFER, GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, GL_ELEMENT_ARRAY_BUFFER,
        GL_PIXEL_PACK_BUFFER, GL_PIXEL_UNPACK_BUFFER, GL_TRANSFORM_FEEDBACK_BUFFER,
        GL_UNIFORM_BUFFER: {
      // version 3.0
    }
    default: {
      glErrorInvalidEnum(target)
    }
  }
  switch (pname) {
    case GL_BUFFER_ACCESS_FLAGS, GL_BUFFER_MAPPED, GL_BUFFER_MAP_LENGTH, GL_BUFFER_MAP_OFFSET,
        GL_BUFFER_SIZE, GL_BUFFER_USAGE: {
      // version 3.0
    }
    default: {
      glErrorInvalidEnum(pname)
    }
  }
  // TODO
}

@Doc("https://www.khronos.org/opengles/sdk/docs/man/xhtml/glGetBufferParameteriv.xml","OpenGL ES 2.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man3/html/glGetBufferParameter.xhtml","OpenGL ES 3.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man31/html/glGetBufferParameter.xhtml","OpenGL ES 3.1")
cmd void glGetBufferParameteriv(GLenum target, GLenum parameter, GLint* value) {
  minRequiredVersion(2, 0)
  switch (target) {
    case GL_ARRAY_BUFFER, GL_ELEMENT_ARRAY_BUFFER: {
      // version 2.0
    }
    case GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, GL_PIXEL_PACK_BUFFER, GL_PIXEL_UNPACK_BUFFER,
        GL_TRANSFORM_FEEDBACK_BUFFER, GL_UNIFORM_BUFFER: {
      minRequiredVersion(3, 0)
    }
    default: {
      glErrorInvalidEnum(target)
    }
  }
  switch (parameter) {
    case GL_BUFFER_SIZE, GL_BUFFER_USAGE: {
      // version 2.0
    }
    case GL_BUFFER_ACCESS_FLAGS, GL_BUFFER_MAPPED, GL_BUFFER_MAP_LENGTH, GL_BUFFER_MAP_OFFSET: {
      minRequiredVersion(3, 0)
    }
    default: {
      glErrorInvalidEnum(parameter)
    }
  }

  ctx := GetContext()
  id := ctx.BoundBuffers[target]
  b := ctx.Instances.Buffers[id]
  value[0] = switch (parameter) {
    case GL_BUFFER_SIZE:  as!GLint(b.Size)
    case GL_BUFFER_USAGE: as!GLint(b.Usage)
  }
}

@Doc("https://www.khronos.org/opengles/sdk/docs/man3/html/glGetBufferPointerv.xhtml","OpenGL ES 3.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man31/html/glGetBufferPointerv.xhtml","OpenGL ES 3.1")
cmd void glGetBufferPointerv(GLenum target, GLenum pname, void** params) {
  minRequiredVersion(3, 0)
  switch (target) {
    case GL_ARRAY_BUFFER, GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, GL_ELEMENT_ARRAY_BUFFER,
        GL_PIXEL_PACK_BUFFER, GL_PIXEL_UNPACK_BUFFER, GL_TRANSFORM_FEEDBACK_BUFFER,
        GL_UNIFORM_BUFFER: {
      // version 3.0
    }
    default: {
      glErrorInvalidEnum(target)
    }
  }
  switch (pname) {
    case GL_BUFFER_MAP_POINTER: {
      // version 3.0
    }
    default: {
      glErrorInvalidEnum(pname)
    }
  }
  // TODO
}

@Doc("https://www.khronos.org/opengles/sdk/docs/man/xhtml/glIsBuffer.xml","OpenGL ES 2.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man3/html/glIsBuffer.xhtml","OpenGL ES 3.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man31/html/glIsBuffer.xhtml","OpenGL ES 3.1")
cmd bool glIsBuffer(BufferId buffer) {
  minRequiredVersion(2, 0)

  ctx := GetContext()
  return buffer in ctx.Instances.Buffers
}

@Doc("https://www.khronos.org/opengles/sdk/docs/man3/html/glMapBufferRange.xhtml","OpenGL ES 3.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man31/html/glMapBufferRange.xhtml","OpenGL ES 3.1")
cmd void* glMapBufferRange(GLenum target, GLintptr offset, GLsizeiptr length, GLbitfield access) {
  minRequiredVersion(3, 0)
  switch (target) {
    case GL_ARRAY_BUFFER, GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, GL_ELEMENT_ARRAY_BUFFER,
        GL_PIXEL_PACK_BUFFER, GL_PIXEL_UNPACK_BUFFER, GL_TRANSFORM_FEEDBACK_BUFFER,
        GL_UNIFORM_BUFFER: {
      // version 3.0
    }
    case GL_ATOMIC_COUNTER_BUFFER, GL_DISPATCH_INDIRECT_BUFFER, GL_DRAW_INDIRECT_BUFFER,
        GL_SHADER_STORAGE_BUFFER: {
      minRequiredVersion(3, 1)
    }
    default: {
      glErrorInvalidEnum(target)
    }
  }
  supportsBits(access, GL_MAP_FLUSH_EXPLICIT_BIT | GL_MAP_INVALIDATE_BUFFER_BIT | GL_MAP_INVALIDATE_RANGE_BIT | GL_MAP_READ_BIT | GL_MAP_UNSYNCHRONIZED_BIT | GL_MAP_WRITE_BIT)
  if (GL_MAP_FLUSH_EXPLICIT_BIT in access) {
  }
  if (GL_MAP_INVALIDATE_BUFFER_BIT in access) {
  }
  if (GL_MAP_INVALIDATE_RANGE_BIT in access) {
  }
  if (GL_MAP_READ_BIT in access) {
  }
  if (GL_MAP_UNSYNCHRONIZED_BIT in access) {
  }
  if (GL_MAP_WRITE_BIT in access) {
  }

  ctx := GetContext()
  b := ctx.Instances.Buffers[ctx.BoundBuffers[target]]

  ptr := as!u8*(?)

  b.MappingAccess = access
  b.MappingData = ptr[0:length]
  if GL_MAP_READ_BIT in access {
    src := b.Data[offset:offset + as!GLintptr(length)]
    dst := b.MappingData
    // copy(dst, src) // TEMP HACK: copy cannot be used here as this is a copy after a fence (ptr := ?)
    write(dst)
  }

  return as!void*(ptr)
}

@Doc("https://www.khronos.org/opengles/sdk/docs/man3/html/glMapBufferRange.xhtml","OpenGL ES 3.0")
@Doc("https://www.khronos.org/opengles/sdk/docs/man31/html/glMapBufferRange.xhtml","OpenGL ES 3.1")
cmd GLboolean glUnmapBuffer(GLenum target) {
  minRequiredVersion(3, 0)
  switch (target) {
    case GL_ARRAY_BUFFER, GL_COPY_READ_BUFFER, GL_COPY_WRITE_BUFFER, GL_ELEMENT_ARRAY_BUFFER,
        GL_PIXEL_PACK_BUFFER, GL_PIXEL_UNPACK_BUFFER, GL_TRANSFORM_FEEDBACK_BUFFER,
        GL_UNIFORM_BUFFER: {
      // version 3.0
    }
    case GL_ATOMIC_COUNTER_BUFFER, GL_DISPATCH_INDIRECT_BUFFER, GL_DRAW_INDIRECT_BUFFER,
        GL_SHADER_STORAGE_BUFFER: {
      minRequiredVersion(3, 1)
    }
    default: {
      glErrorInvalidEnum(target)
    }
  }

  ctx := GetContext()
  b := ctx.Instances.Buffers[ctx.BoundBuffers[target]]
  // if GL_MAP_WRITE_BIT in b.MappingAccess { // TEMP HACK: Commented as 'fence not allowed in *semantic.Branch'
  copy(b.Data[b.MappingOffset:b.MappingOffset + len(b.MappingData)], b.MappingData)
  // }
  return ?
}