import OSLog
import RealityKit
import RealityKitContent
import SwiftUI

struct ThreeSixtySkysphereRealityView: View {
    let logger = Logger(subsystem: SUBSYSTEM, category: "ThreeSixtySkysphereRealityView")
    
    @Environment(\.scenePhase) var scenePhase
    @Environment(AppModel.self) var appModel
    
    let rootEntity = Entity()
    let threeSixtySkysphereEntity = Entity()
    
    var body: some View {
        RealityView { content, attachments in
            logger.info("\(#function) \(#line) `RealityView { content, attachments in`")
            await loadScenes(content: content, attachments: attachments)
            
        } update: { content, attachments in
            logger.info("\(#function) \(#line) `update: { content, attachments in`")
            
        } placeholder: {
            
            let _ = logger.info("\(#function) \(#line) `placeholder`")
            ProgressView()
            
        } attachments: {
            
            let _ = logger.info("\(#function) \(#line) `attachments`")
            
            Attachment(id: "AttachmentID.exitThreeSixty") {
                Button(action: {
                    logger.info("\(#function) \(#line) button pressed")
                    appModel.showingScene = .intro
                }) {
                        Text("Close")
                }
                .glassBackgroundEffect()
                .cornerRadius(25)

            }
        }
    }
    
    func loadScenes(content: RealityViewContent, attachments: RealityViewAttachments) async {
        logger.info("\(#function) \(#line)")
        addSkyboxImage(entity: threeSixtySkysphereEntity)
        rootEntity.addChild(threeSixtySkysphereEntity)
        
        guard let exitThreeSixtyAttachement = attachments.entity(for: "AttachmentID.exitThreeSixty") else {
            logger.error("\(#function) \(#line) missing attachment")
            assertionFailure("missing attachment")
            return
        }
        exitThreeSixtyAttachement.scale = scaleForAttachements
        let anchorEntity = AnchorEntity(world: [0, 0.6, -1.8])
        anchorEntity.addChild(exitThreeSixtyAttachement)
        rootEntity.addChild(anchorEntity)
//        exitThreeSixtyAttachement.isEnabled = false
        content.add(rootEntity)
        
        // This delay in displaying the attachment resolves an issue whereby there would
        // otherwise be a slight flicker and dimming upon initial load of the scene.
//        DispatchQueue.main.asyncAfter(deadline: .now() + .milliseconds(500)) {
//            exitThreeSixtyAttachement.isEnabled = true
//        }
    }
    
    func addSkyboxImage(entity: Entity) {
        do {
            let uiImage = UIImage(named: "Skydome_8k")!
            
            // There is a hard limit of 8,192px width images in this `TextureResource.generate` method
            // If we try to generate a texture from an image of 8,193px width, texture generation will fail.
            let texture = try TextureResource(image: uiImage.cgImage!, options: TextureResource.CreateOptions.init(semantic: nil))
            
            var material = UnlitMaterial()
            material.color = .init(texture: .init(texture))
            entity.components.set(ModelComponent(
                mesh: .generateSphere(radius: 1000),
                materials: [material])
            )
            
            entity.scale *= .init(x: -1, y: 1, z: 1)
            entity.transform.translation += SIMD3(0.0, 1.0, 0.0)
            entity.transform.rotation = simd_quatf(angle: 89.5, axis: [0, 1, 0]) // rotate so that user faces the sea
            
        } catch (let error) {
            logger.error("\(#function) \(#line) texture not loaded with error \(error.localizedDescription)")
            assertionFailure("texture not loaded with error \(error.localizedDescription)")
        }
    }
}

#Preview {
    ThreeSixtySkysphereRealityView()
}