//! Performance benchmarks for core operations.
//!
//! Run with: `cargo bench`
//! First run establishes baseline. Subsequent runs report regressions.

use std::fs;
use std::path::PathBuf;

use criterion::{Criterion, criterion_group, criterion_main};

fn fixture_path(name: &str) -> PathBuf {
    let manifest_dir = env!("CARGO_MANIFEST_DIR");
    PathBuf::from(manifest_dir)
        .join("tests")
        .join("fixtures")
        .join(name)
}

fn load_petstore_json() -> serde_json::Value {
    let path = fixture_path("petstore.json");
    let bytes = fs::read(&path).expect("failed to read petstore.json fixture");
    serde_json::from_slice(&bytes).expect("failed to parse petstore.json")
}

fn bench_json_parse(c: &mut Criterion) {
    let path = fixture_path("petstore.json");
    let bytes = fs::read(&path).expect("failed to read petstore.json fixture");

    c.bench_function("parse_petstore_json", |b| {
        b.iter(|| {
            let _: serde_json::Value = serde_json::from_slice(&bytes).expect("parse failed");
        });
    });
}

fn bench_build_index(c: &mut Criterion) {
    let raw_json = load_petstore_json();

    c.bench_function("build_index_petstore", |b| {
        b.iter(|| {
            // Simulate endpoint extraction (mirrors build_index core logic)
            if let Some(paths) = raw_json.get("paths").and_then(|v| v.as_object()) {
                let mut endpoints = Vec::new();
                for (path, methods) in paths {
                    if let Some(methods_map) = methods.as_object() {
                        for (method, _op) in methods_map {
                            endpoints.push((path.clone(), method.clone()));
                        }
                    }
                }
                assert!(!endpoints.is_empty());
            }
        });
    });
}

fn bench_hash_computation(c: &mut Criterion) {
    let path = fixture_path("petstore.json");
    let bytes = fs::read(&path).expect("failed to read petstore.json");

    c.bench_function("sha256_petstore", |b| {
        b.iter(|| {
            use sha2::{Digest, Sha256};
            let mut hasher = Sha256::new();
            hasher.update(&bytes);
            let _result = format!("sha256:{:x}", hasher.finalize());
        });
    });
}

fn bench_json_pointer_resolution(c: &mut Criterion) {
    let raw_json = load_petstore_json();

    c.bench_function("json_pointer_resolution", |b| {
        b.iter(|| {
            let _ = raw_json
                .pointer("/paths/~1pets/get/summary")
                .map(|v| v.as_str());
            let _ = raw_json
                .pointer("/components/schemas/Pet")
                .map(|v| v.is_object());
            let _ = raw_json.pointer("/info/title").map(|v| v.as_str());
        });
    });
}

fn bench_search_scoring(c: &mut Criterion) {
    let raw_json = load_petstore_json();

    // Pre-extract summaries for search simulation
    let mut summaries: Vec<String> = Vec::new();
    if let Some(paths) = raw_json.get("paths").and_then(|v| v.as_object()) {
        for (_path, methods) in paths {
            if let Some(methods_map) = methods.as_object() {
                for (_method, op) in methods_map {
                    if let Some(summary) = op.get("summary").and_then(|v| v.as_str()) {
                        summaries.push(summary.to_lowercase());
                    }
                }
            }
        }
    }

    c.bench_function("search_scoring_pet", |b| {
        let query = "pet";
        b.iter(|| {
            let mut matches = 0u32;
            for summary in &summaries {
                if summary.contains(query) {
                    matches += 1;
                }
            }
            assert!(matches > 0);
        });
    });
}

criterion_group!(
    benches,
    bench_json_parse,
    bench_build_index,
    bench_hash_computation,
    bench_json_pointer_resolution,
    bench_search_scoring,
);
criterion_main!(benches);