local coreKernels = asset.require("spice/core")



-- Barycenter of the solar system, expressed in the Galactic frame
local SolarSystemBarycenter = {
  Identifier = "SolarSystemBarycenter",
  -- No parent; this node is attached to the scene graph root
  TimeFrame = {
    Type = "TimeFrameInterval",
    Start = "1550-JAN-01",
    End = "2650-JAN-22"
  },
  GUI = {
    Name = "Solar System Barycenter",
    Path = "/Solar System",
    Hidden = true
  }
}

local SunCenter = {
  Identifier = "SunCenter",
  Parent = SolarSystemBarycenter.Identifier,
  Transform = {
    Translation = {
      Type = "SpiceTranslation",
      Target = coreKernels.ID.Sun,
      Observer = coreKernels.ID.SolarSystemBarycenter
    }
  },
  GUI = {
    Name = "Sun Center",
    Path = "/Solar System/Sun",
    Description = "Spice frame for the Sun",
    Hidden = true
  }
}

-- Spice frame for the Sun
local SunIAU = {
  Identifier = "SunIAU",
  Parent = SolarSystemBarycenter.Identifier,
  Transform = {
    Translation = {
      Type = "SpiceTranslation",
      Target = coreKernels.ID.Sun,
      Observer = coreKernels.ID.SolarSystemBarycenter
    },
    Rotation = {
      Type = "SpiceRotation",
      SourceFrame = coreKernels.Frame.Sun,
      DestinationFrame = coreKernels.Frame.Galactic
    }
  },
  GUI = {
    Name = "Sun IAU",
    Path = "/Solar System/Sun",
    Hidden = true
  }
}

local SunEclipJ2000 = {
  Identifier = "SunEclipJ2000",
  Parent = SolarSystemBarycenter.Identifier,
  Transform = {
    Translation = {
      Type = "SpiceTranslation",
      Target = coreKernels.ID.Sun,
      Observer = coreKernels.ID.SolarSystemBarycenter
    },
    Rotation = {
      Type = "SpiceRotation",
      SourceFrame = coreKernels.Frame.EclipJ2000,
      DestinationFrame = coreKernels.Frame.Galactic
    }
  },
  GUI = {
    Name = "Sun J2000",
    Path = "/Solar System/Sun",
    Hidden = true
  }
}

local LightSource = {
  Type = "SceneGraphLightSource",
  Identifier = "Sun",
  Node = SunIAU.Identifier,
  Intensity = 1.0
}


asset.onInitialize(function()
  openspace.addSceneGraphNode(SolarSystemBarycenter)
  openspace.addSceneGraphNode(SunCenter)
  openspace.addSceneGraphNode(SunIAU)
  openspace.addSceneGraphNode(SunEclipJ2000)
end)

asset.onDeinitialize(function()
  openspace.removeSceneGraphNode(SunEclipJ2000)
  openspace.removeSceneGraphNode(SunIAU)
  openspace.removeSceneGraphNode(SunCenter)
  openspace.removeSceneGraphNode(SolarSystemBarycenter)
end)

asset.export(SolarSystemBarycenter)
asset.export(SunCenter)
asset.export(SunIAU)
asset.export(SunEclipJ2000)
asset.export("LightSource", LightSource)



asset.meta = {
  Name = "Sun Transforms",
  Description = "Sun transforms: Solar System Barycenter, SUN IAU and SUN J2000",
  Author = "OpenSpace Team",
  URL = "http://openspaceproject.com",
  License = "MIT license"
}