import XCTest
@testable import MarkBase

class TwelveBConfigFixTest: XCTestCase {
    
    func test12BAfterConfigFix() throws {
        print("\n═══════════════════════════════════════════════════════════════════")
        print("  12B Config Fix Test - Verify 0 NaN After Correction")
        print("═══════════════════════════════════════════════════════════════════\n")
        
        let modelPath = "/Users/accusys/MarkBaseEngine/models/gemma-4-12b-it-4bit"
        
        print("Step 1: Verify config modification...")
        let configPath = modelPath + "/config.json"
        guard let configData = FileManager.default.contents(atPath: configPath) else {
            XCTFail("Config file not found")
            return
        }
        
        let config = try JSONDecoder().decode(ModelConfigStruct.self, from: configData)
        print("  ✓ Config loaded")
        print("    num_attention_heads: \(config.textConfig.numAttentionHeads)")
        print("    num_key_value_heads: \(config.textConfig.numKeyValueHeads ?? 0)")
        print("    hidden_size: \(config.textConfig.hiddenSize)")
        
        if config.textConfig.numKeyValueHeads == 2 {
            print("  ✓✓ Config FIXED: num_kv_heads = 2 (matches weights)")
        } else {
            print("  ✗ Config NOT fixed: num_kv_heads = \(config.textConfig.numKeyValueHeads ?? 0)")
            XCTFail("Config should have num_kv_heads=2")
            return
        }
        
        print("\nStep 2: Load 12B model...")
        let engine = try MarkBaseEngine(autoCompile: true)
        let model = try E4BModel(modelDir: modelPath, engine: engine, maxContextLength: 128)
        print("  ✓ Model loaded")
        print("    Layers: \(model.numHiddenLayers)")
        print("    Hidden: \(model.hiddenSize)")
        print("    Vocab: \(model.vocabSize)")
        
        print("\nStep 3: Test forward pass (multiple positions)...")
        var totalNaN = 0
        let testPositions = [0, 50, 100, 200]
        
        for pos in testPositions {
            let result = try model.forwardOptimized(tokenId: 2, position: pos)
            let nanCount = result.filter { $0.isNaN }.count
            totalNaN += nanCount
            print("  Position \(pos): NaN=\(nanCount)/\(result.count)")
        }
        
        print("\n═══════════════════════════════════════════════════════════════════")
        print("  RESULTS SUMMARY")
        print("═══════════════════════════════════════════════════════════════════\n")
        print("  Total NaN across \(testPositions.count) positions: \(totalNaN)")
        print("  Config fix: num_kv_heads changed from 8 to 2")
        
        if totalNaN == 0 {
            print("  ✓✓✓ SUCCESS! 0 NaN - Config fix resolved the issue!")
            print("  ⭐⭐⭐⭐⭐ 12B now PERFECT after correction")
        } else if totalNaN < 5 {
            print("  ⭐⭐⭐⭐ Improved! NaN reduced (was 3, now \(totalNaN))")
        } else {
            print("  ✗ Config fix did NOT resolve the issue")
            print("  ⚠️ NaN still present: \(totalNaN)")
        }
        
        print("═══════════════════════════════════════════════════════════════════\n")
        
        XCTAssertEqual(totalNaN, 0, "After config fix, should have 0 NaN")
    }
}

struct ModelConfigStruct: Decodable {
    let textConfig: TextConfig
    
    enum CodingKeys: String, CodingKey {
        case textConfig = "text_config"
    }
}

struct TextConfig: Decodable {
    let numAttentionHeads: Int
    let numKeyValueHeads: Int?
    let hiddenSize: Int
    
    enum CodingKeys: String, CodingKey {
        case numAttentionHeads = "num_attention_heads"
        case numKeyValueHeads = "num_key_value_heads"
        case hiddenSize = "hidden_size"
    }
}