use std::{io, fs, env};
use ansi_term::Colour::RGB;

#[derive(Debug)]
struct Hex {
    content: Vec<u8>,
}

impl Hex {
    fn new(file: &str) -> io::Result<Self> { //check documentation for reference
        let content = fs::read(file)?;

        Ok(Self {
            content,
        })
    }

    fn show(&self) {
        println!("╔══════════╦═════════════════════════════════════════════════╦══════════════════╗");
        println!("║ Offset   ║ 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F ║ Content          ║");
        println!("╠══════════╬═════════════════════════════════════════════════╬══════════════════╣");

        let mut offset = 0;
        let mut hexdump = self.content.iter();

        let match_color = |byte, src: String| {
            match byte {
                0 => print!("{}", RGB(200, 200, 200).paint(src)),
                1..=31 => print!("{}", RGB(255, 150, 0).paint(src)),
                32..=126 => print!("{}", RGB(0, 200, 100).paint(src)),
                127..=160 => print!("{}", RGB(100, 0, 100).paint(src)),
                _ => print!("{}", RGB(50, 100, 100).paint(src)),
            }
        };

        self.content.chunks(16).for_each(|chunk| {
            print!("║ {:08X} ║ ", offset);

            for _ in 0..16 {
                match hexdump.next() {
                    Some(b) => {
                        let byte = format!("{:02X}", b);
                        match_color(*b, byte);
                    },
                    _ => print!("  "),
                }

                print!(" ");
            }

            print!("║ ");

            chunk.iter().for_each(|b| {
                let src = match b {
                    0..=31 | 127..=160 => ".".to_string(),
                    _ => (*b as char).to_string(),
                };

                match_color(*b, src);
            });

            println!(" ║");

            offset += 0x10;
        });

        print!("╚══════════╩═══════════════════════════════════════════════════════╩═══════════╝")
    }
}

/* fn help() {
    println!("A CLI hex viewer.\n");
    println!("USAGE:");
    println!("    hexview.exe [COMMAND]\n");
    println!("COMMANDS:");
    println!("    view\t View the raw bytes.");
    println!("    help\t Show this help output.")
} */

fn main() {
    let args: Vec<String> = env::args().collect();

    match args.get(1) {
        Some(p) => {
            let hex = Hex::new(p);

            if let Ok(c) = hex {
                c.show();
            }
        },
        _ => println!("Help command is WIP, enter a file as argument"),
    }
}