use std::{
    env,
    fs::File,
    io::{ErrorKind, Read},
    process::exit,
};

use serde::{Deserialize, Serialize};

#[derive(Serialize, Deserialize, Default, Debug)]
pub enum ScreenType {
    Terminal,
    #[default]
    Window,
}

pub struct Config {
    pub rom: Option<String>,
    pub screen: ScreenType,
    pub char_rom: Option<String>,
}

#[derive(Serialize, Deserialize, Debug)]
struct ConfigBuilder {
    rom: Option<String>,
    char_rom: Option<String>,
    screen: ScreenType,
}

impl ConfigBuilder {
    fn new() -> Self {
        Self {
            rom: None,
            char_rom: None,
            screen: ScreenType::default(),
        }
    }

    fn build(self) -> Config {
        let rom = match self.rom {
            Some(rom) => Some(rom),
            None => {
                println!("no rom was provided :(");
                exit(1);
            }
        };
        let char_rom = self.char_rom;
        let screen = self.screen;

        Config {
            rom,
            screen,
            char_rom,
        }
    }
}

fn help(command: Option<String>) {
    let executable: String = env::args().next().unwrap();
    if let Some(command) = command {
        match &command as &str {
            "rom" | "--rom" | "-r" => {
                println!("{executable} {command} <path>\n\nload a rom/binary from path");
                exit(0);
            }
            "screen" | "--screen" | "-s" => {
                println!("{executable} {command} <path>\n\nload a rom/binary from path");
                exit(0);
            }
            "help" | "--help" | "-h" => {
                println!("{executable} {command} <command>\n\nshow help info for a given command");
                exit(0);
            }
            _ => {
                println!(
                    "{command:?} isn't a valid command!\n\nuse `{executable} help` to see all valid commands",
                );
                exit(1);
            }
        }
    } else {
        println!("ʕ·ᴥ·ʔ- {executable} is an emulator for george:");
        println!("https://git.augustkline.com/august/george\n");
        println!("commands:");
        println!("  help, -h, --help <command>: print help info for any command");
        println!("  rom, -r, --rom <path>: load a rom/binary from path");
        println!("  screen, -s, --screen <type>: use the \"terminal\" or \"window\" display type");
        println!("\nconfiguration:");
        println!("  george-emu searches for a `george.toml` in the current directory.\n  in `george.toml` you can specify a path for the character rom using the key `char_rom` and the main rom/binary with the key `rom`");
        exit(0);
    }
}

pub fn get_input() -> Config {
    let executable: String = env::args().next().unwrap();
    let mut config = ConfigBuilder::new();

    let len = env::args().len();

    if len == 1 {
        config = match File::open("./george.toml") {
            Ok(mut file) => {
                let mut string = String::new();
                file.read_to_string(&mut string).unwrap();
                toml::from_str(string.as_str()).unwrap()
            }
            Err(_) => {
                println!("couldn't find a `george.toml` in the current directory!");
                println!("\nuse `{executable} --help` to see all config options");
                exit(1);
            }
        };
        return config.build();
    }

    let mut args = env::args().skip(1);

    while let Some(arg) = args.next() {
        match &arg[..] {
            "--help" | "-h" | "help" => help(args.next()),
            "--rom" | "-r" | "rom" => {
                if let Some(path) = args.next() {
                    match std::fs::File::open(&path) {
                        Ok(_) => {
                            config.rom = Some(path);
                        }
                        Err(error) => {
                            match error.kind() {
                                ErrorKind::NotFound => {
                                    println!("couldn't find the rom at {path:?}");
                                }
                                ErrorKind::PermissionDenied => {
                                    println!(
                                    "didn't have sufficient permissions to open the rom at {path:?}"
                                );
                                }
                                _ => {
                                    println!("something went wrong! try again in a moment? really not sure why you're getting this error");
                                }
                            }
                            exit(1);
                        }
                    };
                } else {
                    println!("no rom specified!");
                    exit(1);
                }
            }
            "--screen" | "-s" | "screen" => {
                let kind = args.next();
                match kind {
                    Some(kind) => match &kind as &str {
                        "terminal" | "Terminal" | "TERMINAL" | "t" | "term" => {}
                        "window" | "Window" | "WINDOW" | "w" | "win" => {
                            config.screen = ScreenType::Window
                        }
                        _ => {
                            println!("{kind:?} isn't a valid screen type!\n\nuse \"{executable} --help screen\" to see all valid screen types");
                            exit(1);
                        }
                    },
                    None => {
                        println!("no screen type was provided!\n\nuse \"{executable} --help screen\" to see all valid screen types");
                        exit(1);
                    }
                }
            }
            _ => {
                println!("{arg:?} isn't a valid command!\n\nuse \"{executable} help\" to see all valid commands");
                exit(1);
            }
        }
    }
    config.build()
}