import XCTest
@testable import MarkBase

final class AudioGPUTest: XCTestCase {
    func testGPUvsCPU() throws {
        let engine = try MarkBaseEngine(autoCompile: true)
        let extractor = AudioFeatureExtractor(sampleRate: 16000, nMels: 128, nFft: 400, hopLength: 160)

        var audioData = [Float](repeating: 0, count: 16000)
        for i in 0..<audioData.count {
            audioData[i] = sin(2.0 * Float.pi * 440.0 * Float(i) / 16000.0) * 0.5
        }

        let startCPU = CFAbsoluteTimeGetCurrent()
        let cpuResult = extractor.extractMelSpectrogram(from: audioData)
        let cpuTime = CFAbsoluteTimeGetCurrent() - startCPU

        let startGPU = CFAbsoluteTimeGetCurrent()
        let gpuResult = try extractor.extractMelSpectrogramGPU(engine: engine, audioData: audioData)
        let gpuTime = CFAbsoluteTimeGetCurrent() - startGPU

        print("CPU: \(cpuResult.count)×\(cpuResult[0].count) in \(String(format: "%.1f", cpuTime * 1000))ms")
        print("GPU: \(gpuResult.count)×\(gpuResult[0].count) in \(String(format: "%.1f", gpuTime * 1000))ms")
        print("Speedup: \(String(format: "%.1f", cpuTime / gpuTime))×")

        // Compare in linear scale (log10 amplifies noise-floor differences)
        var maxLinearDiff: Float = 0
        var maxRelativeDiff: Float = 0
        var worstF = 0, worstM = 0
        for f in 0..<cpuResult.count {
            for m in 0..<cpuResult[0].count {
                let cLin = pow(10, cpuResult[f][m])
                let gLin = pow(10, gpuResult[f][m])
                let lDiff = abs(cLin - gLin)
                maxLinearDiff = max(maxLinearDiff, lDiff)
                if cLin > 1e-8 {
                    let relDiff = lDiff / cLin
                    if relDiff > maxRelativeDiff {
                        maxRelativeDiff = relDiff
                        worstF = f; worstM = m
                    }
                }
            }
        }
        print("Max linear diff: \(maxLinearDiff)")
        print("Max relative diff: \(maxRelativeDiff) at frame=\(worstF) mel=\(worstM)")
        print("  CPU(lin)=\(pow(10, cpuResult[worstF][worstM])) GPU(lin)=\(pow(10, gpuResult[worstF][worstM]))")
        XCTAssertLessThan(maxLinearDiff, 1e-3, "GPU mel linear values should match CPU")
    }
}