use thiserror::Error;

use crate::asm::data::literal::{DebugMsg, Label, RoutineName, Value};
use crate::asm::data::Register;
use std::borrow::Cow;

#[derive(Error, Debug)]
pub enum Fault {
    #[error("Bad instruction at addr {addr:#10x}: {cause}")]
    BadInstruction {
        addr: u32,
        cause: InstrError,
    },

    #[error("Runtime hit a barrier instruction: {msg}")]
    Barrier {
        msg: DebugMsg,
    },

    #[error("User fault: {msg}")]
    FaultInstr {
        msg: DebugMsg,
    },

    #[error("Program ended.")]
    Halt,

    #[error("Operation not allowed: {0}")]
    NotAllowed(Cow<'static, str>),

    #[error("Object does not exist: {0:#x}")]
    ObjectNotExist(Value),

    // #[error("Memory region {area:?} is locked by thread {owner:?}")]
    // MemoryLocked {
    //     area: MemorySpan,
    //     owner: ThreadToken
    // },
    //
    // #[error("Memory claim {claim:?} owned by thread {owner:?} does not exist")]
    // ClaimNotExist {
    //     claim: ClaimId,
    //     owner: ThreadToken
    // },

    #[error("Register does not exist: {reg:?}")]
    RegisterNotExist {
        reg: Register,
    },

    #[error("Register is read-only: {reg:?}")]
    RegisterNotWritable {
        reg: Register,
    },

    #[error("Called undefined routine: {routine}")]
    NoSuchRoutine {
        routine: RoutineName,
    },

    #[error("Jump to undefined far label: {label}")]
    NoSuchLabel {
        label: Label,
    },

    #[error("Crossed a barrier: {msg}")]
    JumpThroughBarrier {
        msg: DebugMsg,
    },

    #[error("Call stack underflow")]
    CallStackUnderflow,

    #[error("Attempt to read undefined extension data store")]
    ExtDataNotDefined,
}

#[derive(Error, Debug)]
pub enum InstrError {
    #[error("Instruction not recognized")]
    UnknownInstruction,

    #[error("Invalid bit span")]
    BadBitSpan,

    #[error("Operands data size differs")]
    UnevenOperandSize,
}