#[cfg(feature = "serde")]
use serde::{Deserialize, Serialize};

/// Use `PixelFont::px_to_cols` to convert pixels to columns
#[cfg_attr(feature = "serde", derive(Serialize, Deserialize))]
#[derive(Debug, Clone, Eq, PartialEq, Copy, Default)]
pub enum WrappingStrategy {
    #[default]
    /// Don't wrap, may draw off screen
    None,
    /// Splits string at column
    AtCol(usize),
    /// Wraps at the first space before column (acts like AtCol if no space is on that line)
    SpaceBeforeCol(usize),
    /// Same as AtCol but adds a hyphen if it's splitting a word
    AtColWithHyphen(usize),
    /// Chops off the end of string it's over specific length
    Cutoff(usize),
    /// Same as Cutoff but adds an ellipsis
    Ellipsis(usize),
}

impl WrappingStrategy {
    pub fn wrap(&self, input: &str) -> Vec<String> {
        match self {
            WrappingStrategy::None => input.split('\n').map(|s| s.to_string()).collect(),
            WrappingStrategy::AtCol(col) => {
                let mut output = vec![];
                let lines = WrappingStrategy::None.wrap(input);
                for mut line in lines {
                    while line.chars().count() > *col {
                        output.push(line.chars().take(*col).collect());
                        line = line.chars().skip(*col).collect();
                    }
                    output.push(line);
                }
                output
            }
            WrappingStrategy::SpaceBeforeCol(col) => {
                let mut output = vec![];
                let lines = WrappingStrategy::None.wrap(input);
                for mut text in lines {
                    while text.chars().count() > *col {
                        let chars: Vec<char> = text.chars().collect();
                        let line: String = text.chars().take(*col).collect();
                        if line.ends_with(|c: char| c.is_whitespace())
                            || text
                                .chars()
                                .nth(*col)
                                .map(|c| c.is_whitespace())
                                .unwrap_or(false)
                        {
                            output.push(text.chars().take(*col).collect());
                            text = text.chars().skip(*col).collect();
                        } else {
                            let mut whitespace = chars
                                .iter()
                                .take(*col)
                                .rposition(|c| c.is_whitespace())
                                .unwrap_or(0);
                            if whitespace == 0 {
                                whitespace = *col
                            }
                            output.push(text.chars().take(whitespace).collect());
                            text = text.chars().skip(whitespace).collect();
                        }
                    }
                    output.push(text);
                }
                output.iter().map(|s| s.trim().to_string()).collect()
            }
            WrappingStrategy::AtColWithHyphen(col) => {
                let mut output = vec![];
                let lines = WrappingStrategy::None.wrap(input);
                for mut line in lines {
                    while line.chars().count() > *col {
                        let text: String = line.chars().take(*col).collect();
                        if text.chars().last().unwrap_or(' ').is_alphabetic()
                            && line.chars().nth(*col).unwrap_or(' ').is_alphabetic()
                        {
                            output.push(format!("{text}-"));
                        } else {
                            output.push(text.clone());
                        }
                        line = line.chars().skip(*col).collect();
                    }
                    output.push(line)
                }
                output
            }
            WrappingStrategy::Cutoff(col) => input
                .split('\n')
                .map(|line| line.chars().take(*col).collect())
                .collect(),
            WrappingStrategy::Ellipsis(col) => input
                .split('\n')
                .map(|line| {
                    if line.chars().count() >= *col {
                        format!("{}…", line.chars().take(*col).collect::<String>())
                    } else {
                        line.to_string()
                    }
                })
                .collect(),
        }
    }
}

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

    fn c(list: &[&str]) -> Vec<String> {
        list.iter().map(|s| s.to_string()).collect()
    }

    #[test]
    fn none() {
        assert_eq!(None.wrap("this is a test"), c(&["this is a test"]));
        assert_eq!(None.wrap("this is\na test"), c(&["this is", "a test"]));
        assert_eq!(None.wrap("this is \n a test"), c(&["this is ", " a test"]));
    }

    #[test]
    fn at_col() {
        assert_eq!(
            AtCol(4).wrap("some words, and some are longer"),
            c(&["some", " wor", "ds, ", "and ", "some", " are", " lon", "ger"])
        );

        assert_eq!(
            AtCol(5).wrap("Split Here\nBut mid word\nhere"),
            c(&["Split", " Here", "But m", "id wo", "rd", "here"])
        )
    }

    #[test]
    fn at_col_hyphen() {
        assert_eq!(
            AtColWithHyphen(4).wrap("some words, and some are longer"),
            c(&["some", " wor-", "ds, ", "and ", "some", " are", " lon-", "ger"])
        );
        assert_eq!(
            AtColWithHyphen(4).wrap("smol large massive"),
            c(&["smol", " lar-", "ge m-", "assi-", "ve"])
        );
        assert_eq!(
            AtColWithHyphen(4).wrap("smol large\nmassive"),
            c(&["smol", " lar-", "ge", "mass-", "ive"])
        );
    }

    #[test]
    fn space_before_col() {
        assert_eq!(
            SpaceBeforeCol(4).wrap("some words, and some are longer"),
            c(&["some", "wor", "ds,", "and", "some", "are", "lon", "ger"])
        );
        assert_eq!(
            SpaceBeforeCol(8).wrap("some words, and some are longer"),
            c(&["some", "words,", "and some", "are", "longer"])
        );
    }

    #[test]
    fn cutoff() {
        assert_eq!(Cutoff(30).wrap("short test"), c(&["short test"]));
        assert_eq!(Cutoff(10).wrap("longer test string"), c(&["longer tes"]));
        assert_eq!(
            Cutoff(10).wrap("longer\ntest string"),
            c(&["longer", "test strin"])
        );
    }

    #[test]
    fn ellipsis() {
        assert_eq!(Ellipsis(30).wrap("short test"), c(&["short test"]));
        assert_eq!(Ellipsis(10).wrap("longer test string"), c(&["longer tes…"]));
        assert_eq!(
            Ellipsis(10).wrap("longer\ntest string"),
            c(&["longer", "test strin…"])
        );
    }
}