pub mod arc_cow;
pub mod channel;
pub mod fs;
pub mod github;
pub mod http;
pub mod paths;
#[cfg(any(test, feature = "test-support"))]
pub mod test;

use std::{
    borrow::Cow,
    cmp::{self, Ordering},
    ops::{AddAssign, Range, RangeInclusive},
    panic::Location,
    pin::Pin,
    task::{Context, Poll},
};

pub use backtrace::Backtrace;
use futures::Future;
use rand::{seq::SliceRandom, Rng};

pub use take_until::*;

#[macro_export]
macro_rules! debug_panic {
    ( $($fmt_arg:tt)* ) => {
        if cfg!(debug_assertions) {
            panic!( $($fmt_arg)* );
        } else {
            let backtrace = $crate::Backtrace::new();
            log::error!("{}\n{:?}", format_args!($($fmt_arg)*), backtrace);
        }
    };
}

pub fn truncate(s: &str, max_chars: usize) -> &str {
    match s.char_indices().nth(max_chars) {
        None => s,
        Some((idx, _)) => &s[..idx],
    }
}

/// Removes characters from the end of the string if it's length is greater than `max_chars` and
/// appends "..." to the string. Returns string unchanged if it's length is smaller than max_chars.
pub fn truncate_and_trailoff(s: &str, max_chars: usize) -> String {
    debug_assert!(max_chars >= 5);

    let truncation_ix = s.char_indices().map(|(i, _)| i).nth(max_chars);
    match truncation_ix {
        Some(length) => s[..length].to_string() + "…",
        None => s.to_string(),
    }
}

/// Removes characters from the front of the string if it's length is greater than `max_chars` and
/// prepends the string with "...". Returns string unchanged if it's length is smaller than max_chars.
pub fn truncate_and_remove_front(s: &str, max_chars: usize) -> String {
    debug_assert!(max_chars >= 5);

    let truncation_ix = s.char_indices().map(|(i, _)| i).nth_back(max_chars);
    match truncation_ix {
        Some(length) => "…".to_string() + &s[length..],
        None => s.to_string(),
    }
}

pub fn post_inc<T: From<u8> + AddAssign<T> + Copy>(value: &mut T) -> T {
    let prev = *value;
    *value += T::from(1);
    prev
}

/// Extend a sorted vector with a sorted sequence of items, maintaining the vector's sort order and
/// enforcing a maximum length. This also de-duplicates items. Sort the items according to the given callback. Before calling this,
/// both `vec` and `new_items` should already be sorted according to the `cmp` comparator.
pub fn extend_sorted<T, I, F>(vec: &mut Vec<T>, new_items: I, limit: usize, mut cmp: F)
where
    I: IntoIterator<Item = T>,
    F: FnMut(&T, &T) -> Ordering,
{
    let mut start_index = 0;
    for new_item in new_items {
        if let Err(i) = vec[start_index..].binary_search_by(|m| cmp(m, &new_item)) {
            let index = start_index + i;
            if vec.len() < limit {
                vec.insert(index, new_item);
            } else if index < vec.len() {
                vec.pop();
                vec.insert(index, new_item);
            }
            start_index = index;
        }
    }
}

pub fn merge_json_value_into(source: serde_json::Value, target: &mut serde_json::Value) {
    use serde_json::Value;

    match (source, target) {
        (Value::Object(source), Value::Object(target)) => {
            for (key, value) in source {
                if let Some(target) = target.get_mut(&key) {
                    merge_json_value_into(value, target);
                } else {
                    target.insert(key.clone(), value);
                }
            }
        }

        (source, target) => *target = source,
    }
}

pub fn merge_non_null_json_value_into(source: serde_json::Value, target: &mut serde_json::Value) {
    use serde_json::Value;
    if let Value::Object(source_object) = source {
        let target_object = if let Value::Object(target) = target {
            target
        } else {
            *target = Value::Object(Default::default());
            target.as_object_mut().unwrap()
        };
        for (key, value) in source_object {
            if let Some(target) = target_object.get_mut(&key) {
                merge_non_null_json_value_into(value, target);
            } else if !value.is_null() {
                target_object.insert(key.clone(), value);
            }
        }
    } else if !source.is_null() {
        *target = source
    }
}

pub trait ResultExt<E> {
    type Ok;

    fn log_err(self) -> Option<Self::Ok>;
    fn warn_on_err(self) -> Option<Self::Ok>;
    fn inspect_error(self, func: impl FnOnce(&E)) -> Self;
}

impl<T, E> ResultExt<E> for Result<T, E>
where
    E: std::fmt::Debug,
{
    type Ok = T;

    #[track_caller]
    fn log_err(self) -> Option<T> {
        match self {
            Ok(value) => Some(value),
            Err(error) => {
                let caller = Location::caller();
                log::error!("{}:{}: {:?}", caller.file(), caller.line(), error);
                None
            }
        }
    }

    fn warn_on_err(self) -> Option<T> {
        match self {
            Ok(value) => Some(value),
            Err(error) => {
                log::warn!("{:?}", error);
                None
            }
        }
    }

    /// https://doc.rust-lang.org/std/result/enum.Result.html#method.inspect_err
    fn inspect_error(self, func: impl FnOnce(&E)) -> Self {
        if let Err(err) = &self {
            func(err);
        }

        self
    }
}

pub trait TryFutureExt {
    fn log_err(self) -> LogErrorFuture<Self>
    where
        Self: Sized;
    fn warn_on_err(self) -> LogErrorFuture<Self>
    where
        Self: Sized;
    fn unwrap(self) -> UnwrapFuture<Self>
    where
        Self: Sized;
}

impl<F, T, E> TryFutureExt for F
where
    F: Future<Output = Result<T, E>>,
    E: std::fmt::Debug,
{
    fn log_err(self) -> LogErrorFuture<Self>
    where
        Self: Sized,
    {
        LogErrorFuture(self, log::Level::Error)
    }

    fn warn_on_err(self) -> LogErrorFuture<Self>
    where
        Self: Sized,
    {
        LogErrorFuture(self, log::Level::Warn)
    }

    fn unwrap(self) -> UnwrapFuture<Self>
    where
        Self: Sized,
    {
        UnwrapFuture(self)
    }
}

pub struct LogErrorFuture<F>(F, log::Level);

impl<F, T, E> Future for LogErrorFuture<F>
where
    F: Future<Output = Result<T, E>>,
    E: std::fmt::Debug,
{
    type Output = Option<T>;

    fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
        let level = self.1;
        let inner = unsafe { Pin::new_unchecked(&mut self.get_unchecked_mut().0) };
        match inner.poll(cx) {
            Poll::Ready(output) => Poll::Ready(match output {
                Ok(output) => Some(output),
                Err(error) => {
                    log::log!(level, "{:?}", error);
                    None
                }
            }),
            Poll::Pending => Poll::Pending,
        }
    }
}

pub struct UnwrapFuture<F>(F);

impl<F, T, E> Future for UnwrapFuture<F>
where
    F: Future<Output = Result<T, E>>,
    E: std::fmt::Debug,
{
    type Output = T;

    fn poll(self: Pin<&mut Self>, cx: &mut Context) -> Poll<Self::Output> {
        let inner = unsafe { Pin::new_unchecked(&mut self.get_unchecked_mut().0) };
        match inner.poll(cx) {
            Poll::Ready(result) => Poll::Ready(result.unwrap()),
            Poll::Pending => Poll::Pending,
        }
    }
}

pub struct Deferred<F: FnOnce()>(Option<F>);

impl<F: FnOnce()> Deferred<F> {
    /// Drop without running the deferred function.
    pub fn cancel(mut self) {
        self.0.take();
    }
}

impl<F: FnOnce()> Drop for Deferred<F> {
    fn drop(&mut self) {
        if let Some(f) = self.0.take() {
            f()
        }
    }
}

/// Run the given function when the returned value is dropped (unless it's cancelled).
pub fn defer<F: FnOnce()>(f: F) -> Deferred<F> {
    Deferred(Some(f))
}

pub struct RandomCharIter<T: Rng> {
    rng: T,
    simple_text: bool,
}

impl<T: Rng> RandomCharIter<T> {
    pub fn new(rng: T) -> Self {
        Self {
            rng,
            simple_text: std::env::var("SIMPLE_TEXT").map_or(false, |v| !v.is_empty()),
        }
    }

    pub fn with_simple_text(mut self) -> Self {
        self.simple_text = true;
        self
    }
}

impl<T: Rng> Iterator for RandomCharIter<T> {
    type Item = char;

    fn next(&mut self) -> Option<Self::Item> {
        if self.simple_text {
            return if self.rng.gen_range(0..100) < 5 {
                Some('\n')
            } else {
                Some(self.rng.gen_range(b'a'..b'z' + 1).into())
            };
        }

        match self.rng.gen_range(0..100) {
            // whitespace
            0..=19 => [' ', '\n', '\r', '\t'].choose(&mut self.rng).copied(),
            // two-byte greek letters
            20..=32 => char::from_u32(self.rng.gen_range(('α' as u32)..('ω' as u32 + 1))),
            // // three-byte characters
            33..=45 => ['✋', '✅', '❌', '❎', '⭐']
                .choose(&mut self.rng)
                .copied(),
            // // four-byte characters
            46..=58 => ['🍐', '🏀', '🍗', '🎉'].choose(&mut self.rng).copied(),
            // ascii letters
            _ => Some(self.rng.gen_range(b'a'..b'z' + 1).into()),
        }
    }
}

/// Get an embedded file as a string.
pub fn asset_str<A: rust_embed::RustEmbed>(path: &str) -> Cow<'static, str> {
    match A::get(path).unwrap().data {
        Cow::Borrowed(bytes) => Cow::Borrowed(std::str::from_utf8(bytes).unwrap()),
        Cow::Owned(bytes) => Cow::Owned(String::from_utf8(bytes).unwrap()),
    }
}

// copy unstable standard feature option unzip
// https://github.com/rust-lang/rust/issues/87800
// Remove when this ship in Rust 1.66 or 1.67
pub fn unzip_option<T, U>(option: Option<(T, U)>) -> (Option<T>, Option<U>) {
    match option {
        Some((a, b)) => (Some(a), Some(b)),
        None => (None, None),
    }
}

/// Immediately invoked function expression. Good for using the ? operator
/// in functions which do not return an Option or Result
#[macro_export]
macro_rules! iife {
    ($block:block) => {
        (|| $block)()
    };
}

/// Async Immediately invoked function expression. Good for using the ? operator
/// in functions which do not return an Option or Result. Async version of above
#[macro_export]
macro_rules! async_iife {
    ($block:block) => {
        (|| async move { $block })()
    };
}

pub trait RangeExt<T> {
    fn sorted(&self) -> Self;
    fn to_inclusive(&self) -> RangeInclusive<T>;
    fn overlaps(&self, other: &Range<T>) -> bool;
    fn contains_inclusive(&self, other: &Range<T>) -> bool;
}

impl<T: Ord + Clone> RangeExt<T> for Range<T> {
    fn sorted(&self) -> Self {
        cmp::min(&self.start, &self.end).clone()..cmp::max(&self.start, &self.end).clone()
    }

    fn to_inclusive(&self) -> RangeInclusive<T> {
        self.start.clone()..=self.end.clone()
    }

    fn overlaps(&self, other: &Range<T>) -> bool {
        self.start < other.end && other.start < self.end
    }

    fn contains_inclusive(&self, other: &Range<T>) -> bool {
        self.start <= other.start && other.end <= self.end
    }
}

impl<T: Ord + Clone> RangeExt<T> for RangeInclusive<T> {
    fn sorted(&self) -> Self {
        cmp::min(self.start(), self.end()).clone()..=cmp::max(self.start(), self.end()).clone()
    }

    fn to_inclusive(&self) -> RangeInclusive<T> {
        self.clone()
    }

    fn overlaps(&self, other: &Range<T>) -> bool {
        self.start() < &other.end && &other.start <= self.end()
    }

    fn contains_inclusive(&self, other: &Range<T>) -> bool {
        self.start() <= &other.start && &other.end <= self.end()
    }
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn test_extend_sorted() {
        let mut vec = vec![];

        extend_sorted(&mut vec, vec![21, 17, 13, 8, 1, 0], 5, |a, b| b.cmp(a));
        assert_eq!(vec, &[21, 17, 13, 8, 1]);

        extend_sorted(&mut vec, vec![101, 19, 17, 8, 2], 8, |a, b| b.cmp(a));
        assert_eq!(vec, &[101, 21, 19, 17, 13, 8, 2, 1]);

        extend_sorted(&mut vec, vec![1000, 19, 17, 9, 5], 8, |a, b| b.cmp(a));
        assert_eq!(vec, &[1000, 101, 21, 19, 17, 13, 9, 8]);
    }

    #[test]
    fn test_iife() {
        fn option_returning_function() -> Option<()> {
            None
        }

        let foo = iife!({
            option_returning_function()?;
            Some(())
        });

        assert_eq!(foo, None);
    }

    #[test]
    fn test_trancate_and_trailoff() {
        assert_eq!(truncate_and_trailoff("", 5), "");
        assert_eq!(truncate_and_trailoff("èèèèèè", 7), "èèèèèè");
        assert_eq!(truncate_and_trailoff("èèèèèè", 6), "èèèèèè");
        assert_eq!(truncate_and_trailoff("èèèèèè", 5), "èèèèè…");
    }
}