duckfn 0.0.3

//! 错误与 panic 处理辅助：结果别名、错误构造、panic 转查询错误。
//!
//! Error and panic helpers: result aliases, error construction and converting panics into
//! query errors.

use quack_rs::error::ExtensionError;
use quack_rs::prelude::ScalarFunctionInfo;
use std::panic::{UnwindSafe, catch_unwind};
use quack_rs::aggregate::AggregateFunctionInfo;

/// 本 crate 的结果类型别名：错误统一为 quack-rs 的 [`ExtensionError`]。
///
/// Result type alias of this crate: the error is always quack-rs' [`ExtensionError`].
pub type DuckResult<T> = Result<T, ExtensionError>;
/// 「可能为空的结果」类型别名，`Ok(None)` 表示 SQL NULL。
///
/// Alias for a fallible, nullable result; `Ok(None)` represents SQL NULL.
pub type DuckOptionResult<T> = DuckResult<Option<T>>;

/// 由任意字符串构造一个 quack-rs 错误。
///
/// Creates a quack-rs error from any string-like value.
pub fn duck_error(message: impl Into<String>) -> ExtensionError {
    ExtensionError::new(message)
}

/// 把 `catch_unwind` 捕获到的 panic payload 转成 [`ExtensionError`]。
///
/// Converts the panic payload caught by `catch_unwind` into an [`ExtensionError`].
pub fn panic_to_duck_error(e: Box<dyn std::any::Any + Send>) -> ExtensionError {
    duck_error(panic_to_string(e))
}

/// 把 `Vec<Option<T>>` 转成 `Vec<Option<&T>>`，用于按引用批量写入向量。
///
/// Converts `Vec<Option<T>>` into `Vec<Option<&T>>`, used to write a batch of values by
/// reference.
pub fn vec_option_to_ref<T>(vec: &[Option<T>]) -> Vec<Option<&T>> {
    vec.iter().map(Option::as_ref).collect()
}

/// 将panic转换成字符串
///
/// 支持 `&str` 与 `String` 两种 payload，其他情况返回 `"unknown panic"`。
///
/// Converts a panic payload into a string. Both `&str` and `String` payloads are supported;
/// anything else yields `"unknown panic"`.
pub fn panic_to_string(e: Box<dyn std::any::Any + Send>) -> String {
    if let Some(s) = e.downcast_ref::<&str>() {
        s.to_string()
    } else if let Some(s) = e.downcast_ref::<String>() {
        s.clone()
    } else {
        "unknown panic".to_string()
    }
}

/// 处理scalar函数的panic：执行 `f`，panic 时转成查询错误写回 `info`。
///
/// Handles panics in scalar functions: runs `f` and, on panic, reports the message as a query
/// error through `info`.
pub fn duck_scalar_unwind<F: FnOnce() -> R + UnwindSafe, R>(info: &ScalarFunctionInfo, f: F) {
    let unwind = catch_unwind(f);
    if let Err(e) = unwind {
        info.set_error(&panic_to_string(e));
    }
}

/// 处理aggregate函数的panic：执行 `f`，panic 时转成查询错误写回 `info`。
///
/// Handles panics in aggregate functions: runs `f` and, on panic, reports the message as a
/// query error through `info`.
pub fn duck_aggregate_unwind<F: FnOnce() -> R + UnwindSafe, R>(info: &AggregateFunctionInfo, f: F) {
    let unwind = catch_unwind(f);
    if let Err(e) = unwind {
        info.set_error(&panic_to_string(e));
    }
}