use crate::emulator::VBRegister;

pub struct RegisterInfo {
    dwarf: u32,
    name: &'static str,
    set: &'static str,
    alt_name: Option<&'static str>,
    generic: Option<&'static str>,
}

impl RegisterInfo {
    pub fn to_description(&self) -> String {
        let mut string = format!("name:{}", self.name);
        if let Some(alt) = self.alt_name {
            string.push_str(&format!(";alt-name:{}", alt));
        }
        string.push_str(&format!(
            ";bitsize:32;offset:{};encoding:uint;format:hex;set:{};dwarf:{}",
            self.dwarf * 4,
            self.set,
            self.dwarf
        ));
        if let Some(generic) = self.generic {
            string.push_str(&format!(";generic:{}", generic));
        }
        string
    }

    pub fn to_vb_register(&self) -> VBRegister {
        match self.dwarf {
            0..32 => VBRegister::Program(self.dwarf),
            32..40 => VBRegister::System(self.dwarf - 32),
            40..42 => VBRegister::System(self.dwarf - 16),
            42..45 => VBRegister::System(self.dwarf - 13),
            45 => VBRegister::PC,
            other => panic!("unexpected DWARF register {other}"),
        }
    }
}

macro_rules! register {
    ($set:expr, $dwarf:expr, $name:expr) => {
        RegisterInfo {
            dwarf: $dwarf,
            name: $name,
            set: $set,
            alt_name: None,
            generic: None,
        }
    };
    ($set:expr, $dwarf:expr, $name:expr, alt: $alt:expr) => {
        RegisterInfo {
            dwarf: $dwarf,
            name: $name,
            set: $set,
            alt_name: Some($alt),
            generic: None,
        }
    };
    ($set:expr, $dwarf:expr, $name:expr, generic: $generic:expr) => {
        RegisterInfo {
            dwarf: $dwarf,
            name: $name,
            set: $set,
            alt_name: None,
            generic: Some($generic),
        }
    };
    ($set:expr, $dwarf:expr, $name:expr, alt: $alt:expr, generic: $generic:expr) => {
        RegisterInfo {
            dwarf: $dwarf,
            name: $name,
            set: $set,
            alt_name: Some($alt),
            generic: Some($generic),
        }
    };
}

const GENERAL: &str = "General Purpose Registers";
const SPECIAL: &str = "Special Registers";

pub const REGISTERS: [RegisterInfo; 46] = [
    register!(GENERAL, 0, "r0"),
    register!(GENERAL, 1, "r1"),
    register!(GENERAL, 2, "fp", alt: "r2", generic: "fp"),
    register!(GENERAL, 3, "sp", alt: "r3", generic: "sp"),
    register!(GENERAL, 4, "gp", alt: "r4"),
    register!(GENERAL, 5, "tp", alt: "r5"),
    register!(GENERAL, 6, "r6", generic: "arg1"),
    register!(GENERAL, 7, "r7", generic: "arg2"),
    register!(GENERAL, 8, "r8", generic: "arg3"),
    register!(GENERAL, 9, "r9", generic: "arg4"),
    register!(GENERAL, 10, "r10"),
    register!(GENERAL, 11, "r11"),
    register!(GENERAL, 12, "r12"),
    register!(GENERAL, 13, "r13"),
    register!(GENERAL, 14, "r14"),
    register!(GENERAL, 15, "r15"),
    register!(GENERAL, 16, "r16"),
    register!(GENERAL, 17, "r17"),
    register!(GENERAL, 18, "r18"),
    register!(GENERAL, 19, "r19"),
    register!(GENERAL, 20, "r20"),
    register!(GENERAL, 21, "r21"),
    register!(GENERAL, 22, "r22"),
    register!(GENERAL, 23, "r23"),
    register!(GENERAL, 24, "r24"),
    register!(GENERAL, 25, "r25"),
    register!(GENERAL, 26, "r26"),
    register!(GENERAL, 27, "r27"),
    register!(GENERAL, 28, "r28"),
    register!(GENERAL, 29, "r29"),
    register!(GENERAL, 30, "r30"),
    register!(GENERAL, 31, "lp", alt: "r31", generic: "ra"),
    register!(SPECIAL, 32, "eipc", alt: "sr0"),
    register!(SPECIAL, 33, "eipsw", alt: "sr1"),
    register!(SPECIAL, 34, "fepc", alt: "sr2"),
    register!(SPECIAL, 35, "fepsw", alt: "sr3"),
    register!(SPECIAL, 36, "ecr", alt: "sr4"),
    register!(SPECIAL, 37, "psw", alt: "sr5", generic: "flags"),
    register!(SPECIAL, 38, "pir", alt: "sr6"),
    register!(SPECIAL, 39, "tkcw", alt: "sr7"),
    register!(SPECIAL, 40, "chcw", alt: "sr24"),
    register!(SPECIAL, 41, "adtre", alt: "sr25"),
    register!(SPECIAL, 42, "sr29"),
    register!(SPECIAL, 43, "sr30"),
    register!(SPECIAL, 44, "sr31"),
    register!(SPECIAL, 45, "pc", generic: "pc"),
];