//
//  VideoHandler.swift
//  Pocket Poster
//
//  Created by lemin on 6/8/25.
//

import Foundation
import AVFoundation
import UIKit

extension CGImage {
    var png: Data? {
        guard let mutableData = CFDataCreateMutable(nil, 0),
            let destination = CGImageDestinationCreateWithData(mutableData, "public.png" as CFString, 1, nil) else { return nil }
        CGImageDestinationAddImage(destination, self, nil)
        guard CGImageDestinationFinalize(destination) else { return nil }
        return mutableData as Data
    }
    var jpg: Data? {
        let uiimg = UIImage(cgImage: self)
        return uiimg.jpegData(compressionQuality: 0.7)
    }
}

class VideoHandler {
    static func createCaml(from url: URL, autoReverses: Bool) throws -> URL {
        // copy the resources
        let descrURL = SymHandler.getDocumentsDirectory().appendingPathComponent(UUID().uuidString, conformingTo: .directory)
        try FileManager.default.createDirectory(at: descrURL, withIntermediateDirectories: false)
        
        print("pre resource")
        guard let rc = Bundle.main.url(forResource: "VideoCAML", withExtension: nil) else { throw URLError(.fileDoesNotExist) }
        print("post resource")
        try FileManager.default.copyItem(at: rc, to: descrURL.appendingPathComponent("videoCAML"))
        print("post copy")
        
        let coreAnimDir = descrURL.appending(path: "videoCAML/versions/1/contents/9183.Custom-810w-1080h@2x~ipad.wallpaper/9183.Custom_Background-810w-1080h@2x~ipad.ca")
        let assetsFolder = coreAnimDir.appendingPathComponent("assets", conformingTo: .directory)
        if !FileManager.default.fileExists(atPath: assetsFolder.path()) {
            try FileManager.default.createDirectory(at: assetsFolder, withIntermediateDirectories: true)
        }
        
        // load the video
        let asset = AVURLAsset(url: url)
        
        let assetImageGenerator = AVAssetImageGenerator(asset: asset)
        assetImageGenerator.appliesPreferredTrackTransform = true
        assetImageGenerator.apertureMode = AVAssetImageGenerator.ApertureMode.encodedPixels
        
        // create the caml
        guard let track = asset.tracks(withMediaType: .video).first else {
            print("Failed to get video track")
            throw AVError(.decodeFailed)
        }
        let size = track.naturalSize.applying(track.preferredTransform)
        let width = Int(size.width)
        let height = Int(size.height)
        let fps = track.nominalFrameRate
        let duration = CMTimeGetSeconds(asset.duration)
        let totalFrames = Int(fps * Float(duration))
        let animDur = Double(totalFrames) / Double(fps)
        var camlData = """
<?xml version="1.0" encoding="UTF-8"?>
        
<caml xmlns="http://www.apple.com/CoreAnimation/1.0">
<CALayer allowsEdgeAntialiasing="1" allowsGroupOpacity="1" bounds="0 0 \(width) \(height)" contentsFormat="RGBA8" cornerCurve="circular" hidden="0" name="_FLOATING" position="\(Int(width/2)) \(Int(height/2))">
<sublayers>
<CATransformLayer allowsEdgeAntialiasing="1" allowsGroupOpacity="1" allowsHitTesting="1" bounds="0 0 \(width) \(height)" contentsFormat="RGBA8" cornerCurve="circular" name="Chip" position="\(Int(width/2)) \(Int(height/2))">
<sublayers>
<CALayer allowsEdgeAntialiasing="1" allowsGroupOpacity="1" bounds="0 0 \(width) \(height)" contentsFormat="RGBA8" cornerCurve="circular" name="CALayer1" position="\(Int(width/2)) \(Int(height/2))">
<contents type="CGImage" src="assets/0.jpg"/>
<animations>
<animation type="CAKeyframeAnimation" calculationMode="linear" keyPath="contents" beginTime="1e-100" duration="\(animDur)" removedOnCompletion="0" repeatCount="inf" repeatDuration="0" speed="1" timeOffset="0" autoreverses="\(autoReverses ? 1 : 0)">
<values>\n
"""
        
        // go through every frame and add it to the caml
        do {
            let reader = try AVAssetReader(asset: asset)
            let readerOutputSettings: [String: Any] = [
                kCVPixelBufferPixelFormatTypeKey as String: Int(kCVPixelFormatType_32BGRA)
            ]
            
            let readerOutput = AVAssetReaderTrackOutput(track: track, outputSettings: readerOutputSettings)
            reader.add(readerOutput)
            
            reader.startReading()
            
            var frameCount = 0

            while let sampleBuffer = readerOutput.copyNextSampleBuffer(),
                  let imageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer) {
                let name = "\(frameCount).jpg"
                UIApplication.shared.change(title: "Generating Video...", body: "Creating assets/\(name)...")

                let ciImage = CIImage(cvPixelBuffer: imageBuffer)
                let context = CIContext()
                if let cgImage = context.createCGImage(ciImage, from: ciImage.extent) {
                    if let img = cgImage.jpg {
                        try img.write(to: assetsFolder.appendingPathComponent(name))
                        camlData += "\t\t\t<CGImage src=\"assets/\(name)\"/>\n"
                        frameCount += 1
                    }
                }
            }

        } catch {
            print("Error reading asset: \(error)")
        }
        UIApplication.shared.change(title: "Generating Video...", body: "Creating CAML data...")
        
        camlData += """
        </values>
        </animation>
      </animations>
    </CALayer>
  </sublayers>
    </CATransformLayer>
  </sublayers>
  <states>
    <LKState name="Locked">
  <elements/>
    </LKState>
    <LKState name="Unlock">
  <elements/>
    </LKState>
    <LKState name="Sleep">
  <elements/>
    </LKState>
  </states>
  <stateTransitions>
    <LKStateTransition fromState="*" toState="Unlock">
  <elements/>
    </LKStateTransition>
    <LKStateTransition fromState="Unlock" toState="*">
  <elements/>
    </LKStateTransition>
    <LKStateTransition fromState="*" toState="Locked">
  <elements/>
    </LKStateTransition>
    <LKStateTransition fromState="Locked" toState="*">
  <elements/>
    </LKStateTransition>
    <LKStateTransition fromState="*" toState="Sleep">
  <elements/>
    </LKStateTransition>
    <LKStateTransition fromState="Sleep" toState="*">
  <elements/>
    </LKStateTransition>
  </stateTransitions>
</CALayer>
</caml>
"""
        // write the caml
        guard let caData = camlData.data(using: .utf8) else { throw URLError(.unknown) }
        try caData.write(to: coreAnimDir.appendingPathComponent("main.caml"))
        
        // write the other info xml
        camlData = """
        <?xml version="1.0" encoding="UTF-8"?>
        <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
        <plist version="1.0">
        <dict>
            <key>assetManifest</key>
            <string>assetManifest.caml</string>
            <key>documentHeight</key>
            <real>\(height)</real>
            <key>documentResizesToView</key>
            <true/>
            <key>documentWidth</key>
            <real>\(width)</real>
            <key>dynamicGuidesEnabled</key>
            <true/>
            <key>geometryFlipped</key>
            <false/>
            <key>guidesEnabled</key>
            <true/>
            <key>interactiveMouseEventsEnabled</key>
            <true/>
            <key>interactiveShowsCursor</key>
            <true/>
            <key>interactiveTouchEventsEnabled</key>
            <false/>
            <key>loopEnd</key>
            <real>0.0</real>
            <key>loopStart</key>
            <real>0.0</real>
            <key>loopingEnabled</key>
            <false/>
            <key>multitouchDisablesMouse</key>
            <false/>
            <key>multitouchEnabled</key>
            <false/>
            <key>presentationMouseEventsEnabled</key>
            <true/>
            <key>presentationShowsCursor</key>
            <true/>
            <key>presentationTouchEventsEnabled</key>
            <false/>
            <key>rootDocument</key>
            <string>main.caml</string>
            <key>savesWindowFrame</key>
            <false/>
            <key>scalesToFitInPlayer</key>
            <true/>
            <key>showsTouches</key>
            <true/>
            <key>snappingEnabled</key>
            <true/>
            <key>timelineMarkers</key>
            <string>[(null)]</string>
            <key>touchesColor</key>
            <string>1 1 0 0.8</string>
            <key>unitsInPixelsInPlayer</key>
            <true/>
        </dict>
        </plist>
        """
        
        guard let xmlData = camlData.data(using: .utf8) else { throw URLError(.unknown) }
        try xmlData.write(to: coreAnimDir.appendingPathComponent("index.xml", conformingTo: .xml))
        
        return descrURL
    }
}