use std::fmt;

enum Num<'a> {
    Hex(&'a str),
    Dec(i32),
}

impl<'a> fmt::Display for Num<'a> {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        match self {
            Num::Hex(h) => write!(f, "{h}"),
            Num::Dec(d) => write!(f, "{d}"),
        }
    }
}

enum Variable<'a> {
    Int(&'a str, Num<'a>),
    String(&'a str, &'a str),
}

fn contains_string(variables: &[Variable]) -> bool {
    variables.iter().any(|variable| match variable {
        Variable::Int(_, _) => false,
        Variable::String(_, _) => true,
    })
}

fn create_config_struct(content: &str, path: &str, struct_name: &str) {
    let variables: Vec<Variable<'_>> = content
        .lines()
        .map(|line| {
            let mut split = line.split(':');

            let name = split
                .next()
                .unwrap()
                .trim()
                .trim_start_matches('"')
                .trim_end_matches('"');

            let value = split.next().unwrap().trim();

            if value.starts_with('"') {
                let trimmed_string = value.trim_start_matches('"').trim_end_matches('"');

                Variable::String(name, trimmed_string)
            } else {
                Variable::Int(
                    name,
                    if value.starts_with("0x") {
                        Num::Hex(value)
                    } else {
                        Num::Dec(str::parse(value).unwrap())
                    },
                )
            }
        })
        .collect();

    let needs_lifetime = contains_string(&variables);
    let mut file_string = String::new();

    file_string += &format!("pub struct {struct_name}");

    if needs_lifetime {
        file_string += "<'a> ";
    }

    file_string += "{\n";

    for variable in variables.iter() {
        match variable {
            Variable::Int(name, _value) => {
                file_string += &format!("\tpub {name}: i32,\n");
            }
            Variable::String(name, _value) => {
                file_string += &format!("\tpub {name}: &'a str,\n");
            }
        }
    }

    file_string += "}\n\n";

    file_string += "impl";

    if needs_lifetime {
        file_string += "<'a> ";
    }

    file_string += struct_name;

    if needs_lifetime {
        file_string += "<'a> ";
    }

    file_string += "{\n";
    file_string += "\tpub const fn new() -> Self {\n";
    file_string += "\t\tSelf {\n";

    for variable in variables.iter() {
        match variable {
            Variable::Int(name, value) => {
                file_string += &format!("\t\t\t{name}: {value},\n");
            }
            Variable::String(name, value) => {
                file_string += &format!("\t\t\t{name}: \"{value}\",\n");
            }
        }
    }

    file_string += "\t\t}\n";
    file_string += "\t}\n";
    file_string += "}\n";

    std::fs::write(path, file_string).unwrap();
}

fn main() {
    create_config_struct(
        include_str!("serial.conf"),
        "src/serial_config.rs",
        "SerialConfig",
    );
}