use {
    super::{CropWriter, SPACE_FILLING},
    crate::pattern::NameMatch,
    minimad::Alignment,
    termimad::{CompoundStyle, StrFit},
};

pub struct MatchedString<'a> {
    pub name_match: Option<NameMatch>,
    pub string: &'a str,
    pub base_style: &'a CompoundStyle,
    pub match_style: &'a CompoundStyle,
    pub display_width: Option<usize>,
    pub align: Alignment,
}

impl<'a, 'w> MatchedString<'a> {

    pub fn new(
        name_match: Option<NameMatch>,
        string: &'a str,
        base_style: &'a CompoundStyle,
        match_style: &'a CompoundStyle,
    ) -> Self {
        Self {
            name_match,
            string,
            base_style,
            match_style,
            display_width: None,
            align: Alignment::Left,
        }
    }
    /// If the string contains sep, then cut the tail of this matched
    /// string and return it.
    /// Note: a non none display_width currently prevents splitting
    /// (i.e. it's not yet implemented and would involve compute width)
    pub fn split_on_last(&mut self, sep: char) -> Option<Self> {
        if self.display_width.is_some() {
            // the proper algo would need measuring the left part I guess
            None
        } else {
            self.string
                .rfind(sep)
                .map(|sep_idx| {
                    let right = &self.string[sep_idx+1..];
                    self.string = &self.string[..sep_idx+1];
                    let left_chars_count = self.string.chars().count();
                    let right_name_match = self.name_match.as_mut()
                        .map(|nm| nm.cut_after(left_chars_count));
                    MatchedString {
                        name_match: right_name_match,
                        string: right,
                        base_style: self.base_style,
                        match_style: self.match_style,
                        display_width: None,
                        align: self.align,
                    }
                })
        }
    }
    pub fn fill(&mut self, width: usize, align: Alignment) {
        self.display_width = Some(width);
        self.align = align;
    }
    pub fn queue_on<W>(&self, cw: &mut CropWriter<'w, W>) -> Result<(), termimad::Error>
    where
        W: std::io::Write,
    {
        if let Some(m) = &self.name_match {
            let mut pos_idx: usize = 0;
            let mut combined_style = self.base_style.clone();
            combined_style.overwrite_with(self.match_style);
            let mut right_filling = 0;
            let mut s = self.string;
            if let Some(dw) = self.display_width {
                let w = unicode_width::UnicodeWidthStr::width(s);
                #[allow(clippy::comparison_chain)]
                if w > dw {
                    let (count_bytes, _) = StrFit::count_fitting(s, dw);
                    s = &s[0..count_bytes];
                } else if w < dw {
                    match self.align {
                        Alignment::Right => {
                            cw.repeat(self.base_style, &SPACE_FILLING, dw - w)?;
                        }
                        Alignment::Center => {
                            right_filling = (dw - w) / 2;
                            cw.repeat(self.base_style, &SPACE_FILLING, dw - w - right_filling)?;
                        }
                        _ => {
                            right_filling = dw - w;
                        }
                    }
                }
            }
            // we might call queue_char more than allowed but that's okay
            // because the cropwriter will crop them
            for (cand_idx, cand_char) in s.chars().enumerate() {
                if pos_idx < m.pos.len() && m.pos[pos_idx] == cand_idx {
                    cw.queue_char(&combined_style, cand_char)?;
                    pos_idx += 1;
                } else {
                    cw.queue_char(self.base_style, cand_char)?;
                }
            }
            if right_filling > 0 {
                cw.repeat(self.base_style, &SPACE_FILLING, right_filling)?;
            }
        } else if let Some(w) = self.display_width {
            match self.align {
                Alignment::Center => {
                    cw.queue_str(self.base_style, &format!("{:^w$}", self.string, w = w))?;
                }
                Alignment::Right => {
                    cw.queue_str(self.base_style, &format!("{:>w$}", self.string, w = w))?;
                }
                _ => {
                    cw.queue_str(self.base_style, &format!("{:<w$}", self.string, w = w))?;
                }
            }
        } else {
            cw.queue_str(self.base_style, self.string)?;
        }
        Ok(())
    }
}