use crate::{eyre, Buffer, Parse};

use super::OneOf;

#[derive(Debug, Clone, PartialEq)]
/// `AnyOf` is a generic type that implements [`Parse`] to match many characters within the given string
///
/// ```
/// use nommy::{Parse, IntoBuf, text::AnyOf};
/// let mut buffer = "-_-.".chars().into_buf();
/// let c: String = AnyOf::<"-_">::parse(&mut buffer).unwrap().into();
/// assert_eq!(c, "-_-");
/// ```
pub struct AnyOf<const CHARS: &'static str>(String);

impl<const CHARS: &'static str> From<AnyOf<CHARS>> for String {
    fn from(v: AnyOf<CHARS>) -> Self {
        v.0
    }
}

impl<const CHARS: &'static str> Parse<char> for AnyOf<CHARS> {
    fn parse(input: &mut impl Buffer<char>) -> eyre::Result<Self> {
        let mut output = String::new();

        loop {
            let mut cursor = input.cursor();
            match OneOf::<CHARS>::parse(&mut cursor) {
                Ok(c) => output.push(c.into()),
                Err(_) => break,
            }
            cursor.fast_forward_parent();
        }

        Ok(Self(output))
    }

    fn peek(input: &mut impl Buffer<char>) -> bool {
        loop {
            let mut cursor = input.cursor();
            if !OneOf::<CHARS>::peek(&mut cursor) {
                break;
            }
            cursor.fast_forward_parent()
        }
        true
    }
}

#[derive(Debug, Clone, PartialEq)]
/// `WhileNot1` is a generic type that implements [`Parse`] to match many characters not within the given string
///
/// ```
/// use nommy::{Parse, IntoBuf, text::WhileNot1};
/// let mut buffer = "-_-.".chars().into_buf();
/// let c: String = WhileNot1::<".">::parse(&mut buffer).unwrap().into();
/// assert_eq!(c, "-_-");
/// ```
pub struct WhileNot1<const CHARS: &'static str>(String);

impl<const CHARS: &'static str> From<WhileNot1<CHARS>> for String {
    fn from(v: WhileNot1<CHARS>) -> Self {
        v.0
    }
}

impl<const CHARS: &'static str> Parse<char> for WhileNot1<CHARS> {
    fn parse(input: &mut impl Buffer<char>) -> eyre::Result<Self> {
        let mut output = String::new();

        while !OneOf::<CHARS>::peek(&mut input.cursor()) {
            match input.next() {
                None => break,
                Some(c) => output.push(c),
            }
        }

        if output.is_empty() {
            Err(eyre::eyre!("no characters found"))
        } else {
            Ok(Self(output))
        }
    }

    fn peek(input: &mut impl Buffer<char>) -> bool {
        if OneOf::<CHARS>::peek(input) {
            return false;
        }
        loop {
            let mut cursor = input.cursor();
            if OneOf::<CHARS>::peek(&mut cursor) {
                break;
            }
            cursor.fast_forward_parent()
        }
        true
    }
}

#[derive(Debug, Clone, PartialEq)]
/// `AnyOf1` is a generic type that implements [`Parse`] to match many characters within the given string
///
/// ```
/// use nommy::{Parse, IntoBuf, text::AnyOf1};
/// let mut buffer = "-_-.".chars().into_buf();
/// let c: String = AnyOf1::<"-_">::parse(&mut buffer).unwrap().into();
/// assert_eq!(c, "-_-");
/// ```
pub struct AnyOf1<const CHARS: &'static str>(String);

impl<const CHARS: &'static str> From<AnyOf1<CHARS>> for String {
    fn from(v: AnyOf1<CHARS>) -> Self {
        v.0
    }
}

impl<const CHARS: &'static str> Parse<char> for AnyOf1<CHARS> {
    fn parse(input: &mut impl Buffer<char>) -> eyre::Result<Self> {
        let mut output = String::new();

        loop {
            let mut cursor = input.cursor();
            match OneOf::<CHARS>::parse(&mut cursor) {
                Ok(c) => output.push(c.into()),
                Err(_) => break,
            }
            cursor.fast_forward_parent();
        }

        if output.is_empty() {
            Err(eyre::eyre!("no characters found"))
        } else {
            Ok(Self(output))
        }
    }

    fn peek(input: &mut impl Buffer<char>) -> bool {
        if !OneOf::<CHARS>::peek(input) {
            return false;
        }
        loop {
            let mut cursor = input.cursor();
            if !OneOf::<CHARS>::peek(&mut cursor) {
                break;
            }
            cursor.fast_forward_parent()
        }
        true
    }
}

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

    #[test]
    fn any_of_peek() {
        let mut buffer = "1024$".chars().into_buf();
        let mut cursor = buffer.cursor();
        assert!(AnyOf::<"0123456789">::peek(&mut cursor));
        assert_eq!(cursor.next(), Some('$'));
    }
}