// Performance tests for ggen.toml configuration system
// Tests config loading speed and memory efficiency

use anyhow::Result;
use std::path::PathBuf;
use std::time::{Duration, Instant};

#[cfg(test)]
mod performance_tests {
    use super::*;

    fn fixture_path(name: &str) -> PathBuf {
        PathBuf::from(env!("CARGO_MANIFEST_DIR"))
            .join("tests/fixtures/config")
            .join(name)
    }

    #[test]
    fn test_simple_config_load_speed() -> Result<()> {
        // Config loading should be fast (<10ms for simple configs)
        let _config_path = fixture_path("simple.ggen.toml");

        let start = Instant::now();
        // TODO: Uncomment once ggen-config is implemented
        // let _config = GgenConfig::load(&config_path)?;
        let duration = start.elapsed();

        assert!(
            duration < Duration::from_millis(10),
            "Simple config load took {:?}, expected <10ms",
            duration
        );

        Ok(())
    }

    #[test]
    fn test_advanced_config_load_speed() -> Result<()> {
        // Complex config with all features should load quickly (<50ms)
        let _config_path = fixture_path("advanced.ggen.toml");

        let start = Instant::now();
        // TODO: Uncomment once ggen-config is implemented
        // let _config = GgenConfig::load(&config_path)?;
        let duration = start.elapsed();

        assert!(
            duration < Duration::from_millis(50),
            "Advanced config load took {:?}, expected <50ms",
            duration
        );

        Ok(())
    }

    #[test]
    fn test_workspace_config_load_speed() -> Result<()> {
        // Workspace resolution should be efficient (<100ms)
        let _config_path = fixture_path("workspace.ggen.toml");

        let start = Instant::now();
        // TODO: Uncomment once ggen-config is implemented
        // let _config = GgenConfig::load(&config_path)?;
        let duration = start.elapsed();

        assert!(
            duration < Duration::from_millis(100),
            "Workspace config load took {:?}, expected <100ms",
            duration
        );

        Ok(())
    }

    #[test]
    fn test_repeated_config_loads() -> Result<()> {
        // Multiple loads should be consistent in performance
        let _config_path = fixture_path("simple.ggen.toml");
        let mut durations = Vec::new();

        for _ in 0..100 {
            let start = Instant::now();
            // TODO: Uncomment once ggen-config is implemented
            // let _config = GgenConfig::load(&config_path)?;
            durations.push(start.elapsed());
        }

        let avg_duration: Duration = durations.iter().sum::<Duration>() / durations.len() as u32;
        let max_duration = durations.iter().max().unwrap();

        assert!(
            avg_duration < Duration::from_millis(10),
            "Average load time {:?} exceeded 10ms",
            avg_duration
        );

        assert!(
            *max_duration < Duration::from_millis(50),
            "Max load time {:?} exceeded 50ms",
            max_duration
        );

        Ok(())
    }

    #[test]
    fn test_config_memory_usage() -> Result<()> {
        // Config structures should not consume excessive memory
        // TODO: Uncomment once ggen-config is implemented
        // let config_path = fixture_path("advanced.ggen.toml");
        // let config = GgenConfig::load(&config_path)?;
        //
        // let size = std::mem::size_of_val(&config);
        // assert!(
        //     size < 10_000, // 10KB limit for in-memory config
        //     "Config structure too large: {} bytes",
        //     size
        // );

        Ok(())
    }

    #[test]
    fn test_concurrent_config_loads() -> Result<()> {
        // Multiple threads loading configs simultaneously
        use std::thread;

        let handles: Vec<_> = (0..10)
            .map(|i| {
                thread::spawn(move || {
                    let _config_path = fixture_path(if i % 2 == 0 {
                        "simple.ggen.toml"
                    } else {
                        "advanced.ggen.toml"
                    });

                    // TODO: Uncomment once ggen-config is implemented
                    // GgenConfig::load(&config_path)
                    Ok::<(), anyhow::Error>(())
                })
            })
            .collect();

        for handle in handles {
            handle.join().unwrap()?;
        }

        Ok(())
    }

    #[test]
    fn test_large_workspace_performance() -> Result<()> {
        // Test performance with large workspace (many members)
        // This simulates a monorepo with 50+ packages

        // TODO: Create fixture with many members
        // TODO: Measure resolution time
        // Expected: <500ms for 50 members

        Ok(())
    }

    #[test]
    fn test_deep_dependency_graph_performance() -> Result<()> {
        // Test performance with complex dependency trees
        // This simulates deep nested workspace dependencies

        // TODO: Create fixture with deep dependency graph
        // TODO: Measure resolution time
        // Expected: <200ms for 20 depth levels

        Ok(())
    }
}

#[cfg(test)]
mod caching_tests {
    use super::*;

    #[test]
    fn test_config_caching_improves_performance() -> Result<()> {
        // Second load should be faster if caching is enabled
        let _config_path = fixture_path("advanced.ggen.toml");

        // First load (cold)
        let start = Instant::now();
        // TODO: Uncomment once ggen-config is implemented
        // let _config1 = GgenConfig::load(&config_path)?;
        let cold_duration = start.elapsed();

        // Second load (warm, potentially cached)
        let start = Instant::now();
        // TODO: Uncomment once ggen-config is implemented
        // let _config2 = GgenConfig::load(&config_path)?;
        let warm_duration = start.elapsed();

        // Warm load should be at least as fast or faster
        assert!(
            warm_duration <= cold_duration,
            "Warm load ({:?}) slower than cold load ({:?})",
            warm_duration,
            cold_duration
        );

        Ok(())
    }
}

fn fixture_path(name: &str) -> PathBuf {
    PathBuf::from(env!("CARGO_MANIFEST_DIR"))
        .join("tests/fixtures/config")
        .join(name)
}
