#!/usr/bin/env -S cargo +nightly -Zscript
---cargo
[package]
name = "bench_message_serialization"
edition = "2024"

[dependencies]
cargo = { path = "." }
cargo-util-schemas = { path = "crates/cargo-util-schemas" }
criterion = { version = "0.5" }
serde = { version = "1.0", features = ["derive"] }
serde_json = { version = "1.0", features = ["raw_value"] }

[profile.dev]
opt-level = 3
debug = false
---

//! # Machine Message Serialization Benchmark (Criterion-based)
//!
//! ## Quick Start
//! ```sh
//! cargo +nightly -Zscript bench_message_serialization.rs
//! ```
//!
//! ## Overview
//!
//! This benchmark uses criterion.rs for statistically rigorous benchmarking of
//! real message types from the cargo crate (`cargo::util::machine_message`):
//! - BuildFinished (simple)
//! - Artifact (complex)
//!
//! Compares:
//! - Original: Double serialization + string manipulation
//! - Optimized: Single serialization using `#[serde(flatten)]`
//!
//! ## Features
//!
//! - Multiple samples (100) for statistical reliability
//! - Automatic outlier detection and handling
//! - Confidence intervals and variance analysis
//! - Statistical significance testing

use cargo::core::Edition;
use cargo::core::Target;
use cargo::core::compiler::CrateType;
use cargo::util::machine_message::{Artifact, ArtifactDebuginfo, ArtifactProfile, BuildFinished};
use cargo_util_schemas::core::PackageIdSpec;
use criterion::{Criterion, black_box};
use serde::Serialize;
use std::path::PathBuf;
use std::time::Duration;

// ============================================================================
// Trait with Both Original and Optimized Methods
// ============================================================================

pub trait Message: Serialize {
    fn reason(&self) -> &str;

    fn to_json_string_original(&self) -> String {
        // Before: 2 serializations + string concatenation
        let json = serde_json::to_string(self).unwrap();
        assert!(json.starts_with("{\""));
        let reason = serde_json::json!(self.reason());
        format!("{{\"reason\":{},{}", reason, &json[1..])
    }

    fn to_json_string_optimized(&self) -> String {
        // After: 1 serialization using flatten
        #[derive(Serialize)]
        struct WithReason<'a, S: Serialize> {
            reason: &'a str,
            #[serde(flatten)]
            msg: &'a S,
        }
        let with_reason = WithReason {
            reason: self.reason(),
            msg: &self,
        };
        serde_json::to_string(&with_reason).unwrap()
    }
}

impl Message for BuildFinished {
    fn reason(&self) -> &str {
        "build-finished"
    }
}

impl<'a> Message for Artifact<'a> {
    fn reason(&self) -> &str {
        "compiler-artifact"
    }
}

// ============================================================================
// Test Data Builders
// ============================================================================

fn build_finished() -> BuildFinished {
    BuildFinished { success: true }
}

fn artifact<'a>() -> Artifact<'a> {
    let target = Box::leak(Box::new(Target::lib_target(
        "my_package",
        vec![CrateType::Rlib],
        PathBuf::from("/home/user/projects/my-package/src/lib.rs"),
        Edition::Edition2021,
    )));

    Artifact {
        package_id: PackageIdSpec::parse("my-package").unwrap(),
        manifest_path: PathBuf::from("/home/user/projects/my-package/Cargo.toml"),
        target,
        profile: ArtifactProfile {
            opt_level: "3",
            debuginfo: Some(ArtifactDebuginfo::Int(2)),
            debug_assertions: false,
            overflow_checks: false,
            test: false,
        },
        features: vec![
            "default".to_string(),
            "experimental".to_string(),
            "feature3".to_string(),
            "feature4".to_string(),
            "feature5".to_string(),
            "feature6".to_string(),
            "feature7".to_string(),
        ],
        filenames: vec![
            PathBuf::from("/home/user/projects/my-package/target/debug/deps/libmy_package.rlib"),
            PathBuf::from("/home/user/projects/my-package/target/debug/deps/libmy_package.d"),
        ],
        executable: None,
        fresh: false,
    }
}

// ============================================================================
// Benchmark Helper
// ============================================================================

fn benchmark_message<M: Message>(criterion: &mut Criterion, name: &str, msg: M) {
    let mut group = criterion.benchmark_group(name);
    group.sample_size(100);
    group.measurement_time(Duration::from_secs(5));
    group.warm_up_time(Duration::from_secs(3));

    group.bench_function("original", |b| {
        b.iter(|| black_box(&msg).to_json_string_original())
    });

    group.bench_function("optimized", |b| {
        b.iter(|| black_box(&msg).to_json_string_optimized())
    });

    group.finish();
}

// ============================================================================
// Main
// ============================================================================

fn main() {
    let mut criterion = Criterion::default()
        .measurement_time(Duration::from_secs(5))
        .sample_size(100)
        .warm_up_time(Duration::from_secs(3))
        .with_plots();

    eprintln!();
    eprintln!("╔══════════════════════════════════════════════════════════╗");
    eprintln!("║   Machine Message Serialization Benchmark (Criterion)    ║");
    eprintln!("║   Statistical Analysis • Real Cargo Types                ║");
    eprintln!("╚══════════════════════════════════════════════════════════╝");
    eprintln!();

    // Verify correctness before benchmarking
    {
        let bf = build_finished();
        let orig = bf.to_json_string_original();
        let opt = bf.to_json_string_optimized();
        assert_eq!(orig, opt, "BuildFinished outputs don't match!");

        let art = artifact();
        let orig = art.to_json_string_original();
        let opt = art.to_json_string_optimized();
        assert_eq!(orig, opt, "Artifact outputs don't match!");

        eprintln!("✓ Correctness check passed\n");
    }

    eprintln!("📊 Benchmarking BuildFinished (simple message)...");
    eprintln!();
    benchmark_message(&mut criterion, "BuildFinished", build_finished());
    eprintln!();

    eprintln!("📊 Benchmarking Artifact (complex message)...");
    eprintln!();
    benchmark_message(&mut criterion, "Artifact", artifact());
    eprintln!();

    criterion.final_summary();

    eprintln!();
    eprintln!("╔════════════════════════════════════════╗");
    eprintln!("║   Benchmark Complete                   ║");
    eprintln!("║   Results saved to: target/criterion/  ║");
    eprintln!("╚════════════════════════════════════════╝");
    eprintln!();
}