// 隔离同一受检翻倍在内联表达式、Rust 函数边界和 Dever 生成路径上的差异。
// 共享故障元数据以排除错误对象大小和来源内容，原 packages 参照保持不变。

fn shared_fault() -> Fault {
    GENERATED_DISPATCH(i64::MAX).unwrap_err()
}

fn dispatch_generated(values: &[i64]) -> Result<i64, Fault> {
    GENERATED_DISPATCH(values.first().copied().unwrap_or(0))
}

fn adjust_generated(values: &[i64]) -> Result<i64, Fault> {
    GENERATED_ADJUST(values.first().copied().unwrap_or(0))
}

fn inline_reference(values: &[i64]) -> Result<i64, Fault> {
    values
        .first()
        .copied()
        .unwrap_or(0)
        .checked_mul(2)
        .ok_or_else(shared_fault)
}

fn propagated_reference(values: &[i64]) -> Result<i64, Fault> {
    let answer = values
        .first()
        .copied()
        .unwrap_or(0)
        .checked_mul(2)
        .ok_or_else(shared_fault)?;
    Ok(answer)
}

fn helper(value: i64) -> Result<i64, Fault> {
    value.checked_mul(2).ok_or_else(shared_fault)
}

fn helper_reference(values: &[i64]) -> Result<i64, Fault> {
    helper(values.first().copied().unwrap_or(0))
}

#[inline(always)]
fn early_helper(value: i64) -> Result<i64, Fault> {
    value.checked_mul(2).ok_or_else(shared_fault)
}

fn early_helper_reference(values: &[i64]) -> Result<i64, Fault> {
    early_helper(values.first().copied().unwrap_or(0))
}

fn independent_helper(value: i64) -> Result<i64, Fault> {
    value.checked_mul(2).ok_or(&FaultInfo {
        message: "integer arithmetic fault",
        source: "reference.dever",
        line: 1,
        column: 1,
    })
}

fn independent_helper_reference(values: &[i64]) -> Result<i64, Fault> {
    independent_helper(values.first().copied().unwrap_or(0))
}

fn propagated_helper(value: i64) -> Result<i64, Fault> {
    let answer = value.checked_mul(2).ok_or_else(shared_fault)?;
    Ok(answer)
}

fn propagated_helper_reference(values: &[i64]) -> Result<i64, Fault> {
    propagated_helper(values.first().copied().unwrap_or(0))
}

fn batch_generated(values: &[i64]) -> Result<i64, Fault> {
    let mut total = 0i64;
    for value in values {
        total = total
            .checked_add(GENERATED_DISPATCH(*value)?)
            .ok_or_else(shared_fault)?;
    }
    Ok(total)
}

fn batch_reference(values: &[i64]) -> Result<i64, Fault> {
    let mut total = 0i64;
    for value in values {
        let doubled = value.checked_mul(2).ok_or_else(shared_fault)?;
        total = total.checked_add(doubled).ok_or_else(shared_fault)?;
    }
    Ok(total)
}

fn main() {
    let operations = [
        dispatch_generated as fn(&[i64]) -> Result<i64, Fault>,
        adjust_generated,
        inline_reference,
        propagated_reference,
        helper_reference,
        early_helper_reference,
        propagated_helper_reference,
    ];
    for value in [
        i64::MIN,
        i64::MIN / 2 - 1,
        i64::MIN / 2,
        -1,
        0,
        1,
        21,
        i64::MAX / 2,
        i64::MAX / 2 + 1,
        i64::MAX,
    ] {
        for operation in operations {
            assert_eq!(
                operation(&[value]).map_err(|fault| fault.to_string()),
                inline_reference(&[value]).map_err(|fault| fault.to_string())
            );
        }
        assert_eq!(
            independent_helper_reference(&[value]).map_err(|_| ()),
            inline_reference(&[value]).map_err(|_| ())
        );
    }
    for (name, operation) in [
        (
            "dispatch",
            dispatch_generated as fn(&[i64]) -> Result<i64, Fault>,
        ),
        ("adjust", adjust_generated),
        ("propagated", propagated_reference),
        ("helper", helper_reference),
        ("early_helper", early_helper_reference),
        ("independent_helper", independent_helper_reference),
        ("propagated_helper", propagated_helper_reference),
    ] {
        eprintln!(
            "{name}_equals_dispatch={}",
            std::ptr::fn_addr_eq(
                operation,
                dispatch_generated as fn(&[i64]) -> Result<i64, Fault>
            )
        );
    }
    let values = (0..256).map(|index| index * 17 - 2000).collect::<Vec<_>>();
    for input in [
        vec![],
        vec![i64::MAX],
        vec![i64::MIN],
        vec![i64::MAX / 2, 1],
        values.clone(),
    ] {
        assert_eq!(
            batch_generated(&input).map_err(|fault| fault.to_string()),
            batch_reference(&input).map_err(|fault| fault.to_string())
        );
    }
    println!("case,sample,implementation,elapsed_ns,checksum");
    compare(
        "scalar_matched_hot_path",
        &[21],
        3000000,
        adjust_generated,
        independent_helper_reference,
        |value| *value as u64,
    );
    compare(
        "scalar_inline",
        &[21],
        3000000,
        dispatch_generated,
        inline_reference,
        |value| *value as u64,
    );
    compare_named(
        "scalar_direct",
        &[21],
        3000000,
        dispatch_generated,
        adjust_generated,
        |value| *value as u64,
        "direct",
    );
    compare(
        "scalar_propagated",
        &[21],
        3000000,
        dispatch_generated,
        propagated_reference,
        |value| *value as u64,
    );
    compare(
        "scalar_helper",
        &[21],
        3000000,
        dispatch_generated,
        helper_reference,
        |value| *value as u64,
    );
    compare(
        "scalar_early_helper",
        &[21],
        3000000,
        dispatch_generated,
        early_helper_reference,
        |value| *value as u64,
    );
    compare(
        "scalar_independent_helper",
        &[21],
        3000000,
        dispatch_generated,
        independent_helper_reference,
        |value| *value as u64,
    );
    compare(
        "scalar_propagated_helper",
        &[21],
        3000000,
        dispatch_generated,
        propagated_helper_reference,
        |value| *value as u64,
    );
    compare(
        "scalar_batch",
        &values,
        30000,
        batch_generated,
        batch_reference,
        |value| *value as u64,
    );
}