using System;

namespace XCEngine.Rendering.RenderGraphModule
{
    public sealed class RenderGraph
    {
        private readonly XCEngine.Rendering.ScriptableRenderContext
            m_context;

        public RenderGraph()
            : this(null)
        {
        }

        public RenderGraph(
            XCEngine.Rendering.ScriptableRenderContext context)
        {
            m_context = context;
        }

        public XCEngine.Rendering.RenderGraphRasterPassBuilder
        AddRasterPass(
            string passName)
        {
            if (m_context == null)
            {
                throw new InvalidOperationException(
                    "RenderGraph is not bound to a recording context.");
            }

            return m_context.AddRasterPass(passName);
        }

        public XCEngine.Rendering.RenderGraphTextureHandle
        CreateTransientTexture(
            string name,
            XCEngine.Rendering.RenderGraphTextureDesc desc)
        {
            if (m_context == null)
            {
                throw new InvalidOperationException(
                    "RenderGraph is not bound to a recording context.");
            }

            return m_context.CreateTransientTexture(
                name,
                desc);
        }

        public XCEngine.Rendering.RenderGraphTextureHandle
        CreateFullscreenTransientColorTexture(
            string name)
        {
            if (m_context == null)
            {
                throw new InvalidOperationException(
                    "RenderGraph is not bound to a recording context.");
            }

            return m_context.CreateFullscreenTransientColorTexture(name);
        }

        public XCEngine.Rendering.RenderGraphTextureHandle
        CreateFullscreenTransientDepthTexture(
            string name)
        {
            if (m_context == null)
            {
                throw new InvalidOperationException(
                    "RenderGraph is not bound to a recording context.");
            }

            return m_context.CreateFullscreenTransientDepthTexture(name);
        }

        public XCEngine.Rendering.RendererListHandle
        CreateRendererList(
            XCEngine.Rendering.RendererListDesc rendererListDesc)
        {
            return CreateRendererList(
                rendererListDesc,
                XCEngine.Rendering.DrawingSettings.CreateDefault());
        }

        public XCEngine.Rendering.RendererListHandle
        CreateRendererList(
            XCEngine.Rendering.RendererListDesc rendererListDesc,
            XCEngine.Rendering.DrawingSettings drawingSettings)
        {
            if (m_context == null)
            {
                throw new InvalidOperationException(
                    "RenderGraph is not bound to a recording context.");
            }

            return m_context.CreateRendererList(
                rendererListDesc,
                drawingSettings);
        }

        internal string passName =>
            m_context != null
                ? m_context.passName
                : string.Empty;

        public XCEngine.Rendering.RenderGraphTextureHandle
        sourceColorTexture =>
            m_context != null
                ? m_context.sourceColorTexture
                : default;

        public XCEngine.Rendering.RenderGraphTextureHandle
        primaryColorTarget =>
            m_context != null
                ? m_context.primaryColorTarget
                : default;

        public XCEngine.Rendering.RenderGraphTextureHandle
        depthTarget =>
            m_context != null
                ? m_context.depthTarget
                : default;
    }
}