use anyhow::Result;
use std::fs;
use std::io::Write;
use std::path::Path;
use std::time::{Duration, Instant};

struct CopyTestResult {
    total_files: usize,
    total_size: u64,
    copy_time: Duration,
    throughput: f64,
    avg_latency: Duration,
}

impl CopyTestResult {
    fn print_summary(&self, label: &str) {
        println!("\n{} Results:", label);
        println!("  Files copied: {}", self.total_files);
        println!(
            "  Total size: {:.2} MB",
            self.total_size as f64 / 1024.0 / 1024.0
        );
        println!("  Copy time: {:?}", self.copy_time);
        println!("  Throughput: {:.2} MB/sec", self.throughput);
        println!("  Avg latency: {:?}", self.avg_latency);
    }
}

fn main() -> Result<()> {
    println!("=== Multi-File Copy Performance Test ===\n");

    println!("Configuration:");
    println!("  Test files: 10,000");
    println!("  File size: 1KB each (total ~10MB)");
    println!("  Test 1: Traditional std::fs::copy");
    println!("  Test 2: Hybrid Architecture + Cache Warmup");
    println!("  Test 3: Comparison Analysis");

    println!("\n=== Phase 1: Prepare Test Environment ===");

    let test_dir = "/tmp/copy_test_source";
    let target_traditional = "/tmp/copy_test_traditional";
    let target_hybrid = "/tmp/copy_test_hybrid";

    println!("\nStep 1: Create test files...");
    create_test_files(test_dir, 10000)?;

    let test_files = collect_test_files(test_dir)?;
    println!("  ✓ Created {} test files", test_files.len());

    println!("\n=== Phase 2: Traditional Copy Test ===");

    fs::create_dir_all(target_traditional)?;
    let traditional_result = test_traditional_copy(&test_files, target_traditional)?;
    traditional_result.print_summary("Traditional std::fs::copy");

    println!("\n=== Phase 3: Hybrid Copy Test (with Prepare) ===");

    println!("\nStep 2: Initialize Hybrid Router...");
    use filetree_hybrid::HybridRouter;
    let router = HybridRouter::init_user_db("copy_test")?;

    println!("\nStep 3: Prepare - Cache Warmup...");
    let warmup_start = Instant::now();

    for (idx, file_path) in test_files.iter().enumerate().take(1000) {
        let file_name = file_path.file_name().unwrap().to_str().unwrap();
        let node = filetree_hybrid::HybridRouter::new_folder(file_name, None);
        router.insert_node(&node)?;

        if idx % 100 == 0 {
            println!("  Warmup progress: {}/1000 files", idx);
        }
    }

    let warmup_time = warmup_start.elapsed();
    println!("  ✓ Cache warmed up: {:?}", warmup_time);

    println!("\nStep 4: Hybrid Copy (with cache lookup)...");
    fs::create_dir_all(target_hybrid)?;

    let hybrid_start = Instant::now();
    let mut copied_files = 0;
    let mut total_bytes = 0;

    for (idx, src_file) in test_files.iter().enumerate() {
        let file_name = src_file.file_name().unwrap().to_str().unwrap();

        if let Some(_cache) = router.get_node(&file_name.replace(".", ""))? {
            let target_file = Path::new(target_hybrid).join(file_name);

            let file_size = src_file.metadata()?.len();
            fs::copy(src_file, &target_file)?;

            copied_files += 1;
            total_bytes += file_size;
        } else {
            let target_file = Path::new(target_hybrid).join(file_name);
            fs::copy(src_file, &target_file)?;
            copied_files += 1;
            total_bytes += src_file.metadata()?.len();
        }

        if idx % 1000 == 0 {
            println!("  Copy progress: {}/10000 files", idx);
        }
    }

    let hybrid_time = hybrid_start.elapsed();
    let hybrid_result = CopyTestResult {
        total_files: copied_files,
        total_size: total_bytes,
        copy_time: hybrid_time,
        throughput: total_bytes as f64 / hybrid_time.as_secs_f64(),
        avg_latency: hybrid_time / copied_files as u32,
    };

    hybrid_result.print_summary("Hybrid Copy (with Prepare)");

    println!("\n=== Phase 4: Performance Comparison ===");

    println!("\nComparison Table:");
    println!("┌─────────────────────────────────────────┐");
    println!("│ Metric              │ Traditional │ Hybrid  │");
    println!("├─────────────────────────────────────────┤");
    println!(
        "│ Copy time           │ {:?} │ {:?} │",
        traditional_result.copy_time, hybrid_result.copy_time
    );
    println!(
        "│ Throughput          │ {:.2} MB/s  │ {:.2} MB/s │",
        traditional_result.throughput / 1024.0 / 1024.0,
        hybrid_result.throughput / 1024.0 / 1024.0
    );
    println!(
        "│ Avg latency         │ {:?} │ {:?} │",
        traditional_result.avg_latency, hybrid_result.avg_latency
    );
    println!(
        "│ Speedup             │ 1.00x      │ {:.2}x   │",
        traditional_result.copy_time.as_nanos() as f64 / hybrid_result.copy_time.as_nanos() as f64
    );
    println!("└─────────────────────────────────────────┘");

    let speedup =
        traditional_result.copy_time.as_nanos() as f64 / hybrid_result.copy_time.as_nanos() as f64;

    if speedup > 1.5 {
        println!("\n✅ SIGNIFICANT IMPROVEMENT: {:.2}x faster!", speedup);
        println!("   Hybrid architecture significantly improves multi-file copy performance.");
    } else if speedup > 1.1 {
        println!("\n✅ MODERATE IMPROVEMENT: {:.2}x faster", speedup);
        println!("   Hybrid architecture provides moderate improvement.");
    } else {
        println!("\n⚠️ NO SIGNIFICANT IMPROVEMENT: {:.2}x", speedup);
        println!("   Consider further optimizations:");
        println!("   - Larger cache warmup (more files)");
        println!("   - Batch copy operations");
        println!("   - Parallel copy threads");
    }

    println!("\n=== Phase 5: Cleanup ===");

    fs::remove_dir_all(test_dir)?;
    fs::remove_dir_all(target_traditional)?;
    fs::remove_dir_all(target_hybrid)?;

    let db_path = filetree_hybrid::HybridRouter::user_db_path("copy_test");
    let sqlite_path = format!("{}.sqlite", db_path);
    let sled_path = format!("{}.sled", db_path);

    fs::remove_file(&sqlite_path)?;
    fs::remove_dir_all(&sled_path)?;

    println!("  ✓ Test environment cleaned up");

    println!("\n✅ Multi-File Copy Test completed successfully!");

    Ok(())
}

fn create_test_files(dir: &str, count: usize) -> Result<()> {
    fs::create_dir_all(dir)?;

    for i in 0..count {
        let file_path = Path::new(dir).join(format!("test_file_{:05}.txt", i));
        let mut file = fs::File::create(&file_path)?;

        let content = format!("Test file {} content\n", i);
        file.write_all(content.as_bytes())?;

        if i % 1000 == 0 {
            println!("  Creating progress: {}/{} files", i, count);
        }
    }

    Ok(())
}

fn collect_test_files(dir: &str) -> Result<Vec<std::path::PathBuf>> {
    let mut files = Vec::new();

    for entry in fs::read_dir(dir)? {
        let entry = entry?;
        if entry.file_type()?.is_file() {
            files.push(entry.path());
        }
    }

    Ok(files)
}

fn test_traditional_copy(files: &[std::path::PathBuf], target: &str) -> Result<CopyTestResult> {
    let start = Instant::now();
    let mut copied_files = 0;
    let mut total_bytes = 0;

    for (idx, src_file) in files.iter().enumerate() {
        let file_name = src_file.file_name().unwrap().to_str().unwrap();
        let target_file = Path::new(target).join(file_name);

        let file_size = src_file.metadata()?.len();
        fs::copy(src_file, &target_file)?;

        copied_files += 1;
        total_bytes += file_size;

        if idx % 1000 == 0 {
            println!("  Copy progress: {}/{} files", idx, files.len());
        }
    }

    let elapsed = start.elapsed();

    Ok(CopyTestResult {
        total_files: copied_files,
        total_size: total_bytes,
        copy_time: elapsed,
        throughput: total_bytes as f64 / elapsed.as_secs_f64(),
        avg_latency: elapsed / copied_files as u32,
    })
}