pub fn stdout_and_stderr(out: std::process::Output) -> String {
    let out = if !out.stdout.is_empty() {
        out.stdout
    } else {
        out.stderr
    };

    String::from_utf8(out).unwrap_or_default()
}

pub fn remove_main(script: &str) -> String {
    const MAIN_FN: &str = "fn main() {";

    let mut script = remove_comments(script);

    let main_start = match script.find(MAIN_FN) {
        Some(idx) if balanced_quotes(&script[..idx]) => idx,
        _ => return script,
    };

    let open_tag = main_start + MAIN_FN.len();

    let mut close_tag = None;

    // look for closing tag
    let mut tag_score = 1;
    for (idx, character) in script[open_tag + 1..].chars().enumerate() {
        if character == '{' {
            tag_score += 1;
        }
        if character == '}' {
            tag_score -= 1;
            if tag_score == 0 {
                close_tag = Some(idx);
                break;
            }
        }
    }
    if let Some(close_tag) = close_tag {
        script.remove(open_tag + close_tag + 1);
        script.replace_range(main_start..=open_tag, "");
    }
    script
}

pub struct StringTools {}

impl StringTools {
    pub fn _insert_at_char_idx(buffer: &mut String, idx: usize, character: char) {
        let mut buffer_chars: Vec<char> = buffer.chars().collect();
        buffer_chars.insert(idx, character);
        *buffer = buffer_chars.into_iter().collect();
    }

    pub fn _remove_at_char_idx(buffer: &mut String, idx: usize) -> Option<char> {
        let mut buffer_chars: Vec<char> = buffer.chars().collect();

        let removed_char = if buffer_chars.len() > idx {
            Some(buffer_chars.remove(idx))
        } else {
            None
        };

        *buffer = buffer_chars.into_iter().collect();

        removed_char
    }

    pub fn _get_char_at_idx(buffer: &str, idx: usize) -> Option<char> {
        let buffer_chars: Vec<char> = buffer.chars().collect();
        buffer_chars.into_iter().nth(idx)
    }

    pub fn chars_count(buffer: &str) -> usize {
        buffer.chars().count()
    }

    pub fn new_lines_count(buffer: &str) -> usize {
        buffer.chars().filter(|c| c == &'\n').count()
    }

    pub fn _is_multiline(string: &str) -> bool {
        string.chars().filter(|c| *c == '\n').count() > 1
    }

    pub fn strings_unique(s1: &str, s2: &mut String) {
        let mut idx = s2.len();
        loop {
            if !s2[..idx].is_empty() && s1.ends_with(&s2[..idx]) {
                for _ in 0..idx {
                    s2.remove(0);
                }
                break;
            }
            if idx == 0 {
                if let Some(last_char) = s1.chars().last() {
                    if last_char.is_alphanumeric() {
                        s2.clear();
                    }
                }
                break;
            }

            idx -= 1;
        }
    }

    pub fn unmatched_brackets(s: &str) -> bool {
        let s = remove_comments(s);
        let mut braces = std::collections::HashMap::new();
        braces.insert('(', 0);
        braces.insert('[', 0);
        braces.insert('{', 0);

        let mut quote = false;
        let mut double_quote = false;
        let mut previous_char = ' ';
        for character in s.chars() {
            // safe unwraps ahead
            match character {
                '(' => {
                    if !quote && !double_quote {
                        *braces.get_mut(&'(').unwrap() += 1;
                    }
                }
                ')' => {
                    if !quote && !double_quote {
                        *braces.get_mut(&'(').unwrap() -= 1;
                    }
                }
                '[' => {
                    if !quote && !double_quote {
                        *braces.get_mut(&'[').unwrap() += 1;
                    }
                }
                ']' => {
                    if !quote && !double_quote {
                        *braces.get_mut(&'[').unwrap() -= 1;
                    }
                }
                '{' => {
                    if !quote && !double_quote {
                        *braces.get_mut(&'{').unwrap() += 1;
                    }
                }
                '}' => {
                    if !quote && !double_quote {
                        *braces.get_mut(&'{').unwrap() -= 1;
                    }
                }
                '"' => {
                    if previous_char != '\\' {
                        double_quote = !double_quote;
                    }
                }
                '\'' => {
                    if previous_char != '\\' {
                        quote = !quote;
                    }
                }
                _ => (),
            }
            previous_char = character;
        }

        braces[&'('] != 0 || braces[&'['] != 0 || braces[&'{'] != 0
    }
}

pub fn read_until_bytes<R: std::io::BufRead + ?Sized>(
    r: &mut R,
    delim: &[u8],
    buffer: &mut Vec<u8>,
) -> std::io::Result<usize> {
    let mut read = 0;
    let mut count = 0;
    loop {
        let (done, used) = {
            let available = match r.fill_buf() {
                Ok(n) => n,
                Err(ref e) if e.kind() == std::io::ErrorKind::Interrupted => continue,
                Err(e) => return Err(e),
            };
            match available.iter().position(|b| *b == delim[count]) {
                Some(i) => {
                    buffer.extend_from_slice(&available[..=i]);

                    count += 1;
                    if count == delim.len() {
                        (true, i + 1)
                    } else {
                        (false, i + 1)
                    }
                }
                None => {
                    count = 0;
                    buffer.extend_from_slice(available);
                    (false, available.len())
                }
            }
        };
        r.consume(used);
        read += used;
        if done || used == 0 {
            return Ok(read);
        }
    }
}

fn remove_comments(s: &str) -> String {
    s.lines()
        .filter(|l| !l.trim_start().starts_with("//"))
        .map(|l| {
            let mut quote = false;
            let mut d_quote = false;

            let mut l = l.chars().peekable();
            let mut purged_line = String::new();

            loop {
                match (l.next(), l.peek()) {
                    (Some('/'), Some('/')) => {
                        if !quote && !d_quote {
                            break;
                        }
                    }
                    (Some('\''), _) => {
                        quote = !quote;
                        purged_line.push('\'');
                    }
                    (Some('"'), _) => {
                        d_quote = !d_quote;
                        purged_line.push('"');
                    }
                    (Some(c), _) => purged_line.push(c),
                    _ => break,
                }
            }
            purged_line + "\n"
        })
        .collect()
}

fn balanced_quotes(s: &str) -> bool {
    s.match_indices(|p| p == '"' || p == '\'').count() % 2 == 0
}