//! Deterministic benchmarks for the pure payment domain (review item 7.7).
//!
//! These use the stable-Rust harness rather than `#![feature(test)]` or an
//! extra dependency, so they run under the repository's pinned toolchain and
//! in CI without a nightly compiler.
//!
//! They measure only pure, allocation-bounded work: no clock skew from I/O, no
//! gateway, no database. Run with:
//!
//! ```bash
//! cargo bench -p nigig-pay-domain
//! ```

use std::time::{Duration, Instant};

use nigig_pay_domain::evidence::{
    body_digest, EvidenceLog, EvidenceSentiment, EvidenceSource, ObservedEvidence,
};
use nigig_pay_domain::fee::compute_adjusted_amount;
use nigig_pay_domain::money::Money;
use nigig_pay_domain::payment_intent::{PaymentIntent, PaymentState};
use nigig_pay_domain::validation::validate_phone;

/// Run `iterations` of `body` and report the total and per-operation cost.
fn bench(name: &str, iterations: u32, mut body: impl FnMut()) -> Duration {
    // One warm-up pass so first-call allocation does not dominate.
    body();
    let start = Instant::now();
    for _ in 0..iterations {
        body();
    }
    let elapsed = start.elapsed();
    let per_op = elapsed / iterations;
    println!("{name:<44} {iterations:>7} iters  {elapsed:>12.3?} total  {per_op:>10.3?}/op");
    elapsed
}

fn bench_money_formatting() {
    bench("money_format_ksh", 100_000, || {
        let amount = Money::from_major(1_234_567);
        std::hint::black_box(amount.format_ksh());
    });
}

fn bench_phone_validation() {
    let inputs = [
        "0712345678",
        "+254712345678",
        "254112345678",
        "0712 345 678",
        "not-a-phone",
    ];
    bench("validate_100_phone_numbers", 1_000, || {
        for _ in 0..20 {
            for input in inputs.iter() {
                std::hint::black_box(validate_phone(input).ok());
            }
        }
    });
}

fn bench_fee_quotes() {
    bench("compute_100_fee_quotes", 1_000, || {
        for index in 0..100u64 {
            let quote = compute_adjusted_amount(
                Money::from_major(1_000 + index),
                Ok(Money::from_major(23)),
                Some(Ok(Money::from_major(34))),
                index % 2 == 0,
                index % 3 == 0,
            );
            std::hint::black_box(quote.ok());
        }
    });
}

fn bench_state_machine() {
    bench("drive_1000_intents_through_lifecycle", 100, || {
        for _ in 0..1_000 {
            let mut intent = PaymentIntent::new(
                Money::from_major(1_000),
                Money::from_major(23),
                "254712345678".into(),
                "Send Money".into(),
            );
            let _ = intent.transition(PaymentState::Dispatching);
            let _ = intent.transition(PaymentState::Submitted);
            let _ = intent.transition(PaymentState::Confirmed);
            std::hint::black_box(&intent);
        }
    });
}

fn bench_evidence_digest() {
    let body = "QWE123 Confirmed. Ksh1,000.00 sent to ADA LOVELACE 254712345678 \
                on 27/7/26 at 2:15 PM. New M-PESA balance is Ksh4,321.00.";
    bench("digest_1000_sms_bodies", 100, || {
        for index in 0..1_000 {
            std::hint::black_box(body_digest(&format!("{body}{index}")));
        }
    });
}

fn bench_evidence_dedup() {
    // The de-duplication scan is linear in log length, so measure the cost of
    // a realistically noisy log rather than a single insert.
    bench("record_200_evidence_entries", 500, || {
        let mut log = EvidenceLog::new();
        let amount = Money::from_major(1_000);
        for index in 0..200 {
            let evidence = ObservedEvidence::new(
                EvidenceSource::Sms {
                    sender: "MPESA".into(),
                },
                EvidenceSentiment::Indeterminate,
                index as i64,
                body_digest(&format!("message-{index}")),
            );
            std::hint::black_box(log.record(evidence, amount));
        }
    });
}

fn main() {
    println!("nigig-pay-domain benchmarks (pure domain, no I/O)");
    println!("{}", "-".repeat(96));
    bench_money_formatting();
    bench_phone_validation();
    bench_fee_quotes();
    bench_state_machine();
    bench_evidence_digest();
    bench_evidence_dedup();
    println!("{}", "-".repeat(96));
    println!("done");
}