use sexp::SourcePosition;

use crate::asm::data::{Rd, RdObj, Wr, RdWr};
use crate::asm::data::literal::{DebugMsg, Label, RoutineName};
use crate::asm::instr::Op;
use crate::asm::instr::op::OpKind;

#[derive(Debug)]
pub enum Barrier {
    /// Barrier that logically opens a section that cannot be jumped into, typically a routine
    Open(Label),
    /// Closing counterpart to the Open barrier
    Close(Label),
    /// Stand-alone barrier
    Standalone,
}

#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub enum SleepUnit {
    Usec, Msec, Sec
}

impl SleepUnit {
    pub fn micros(self) -> u64 {
        match self {
            SleepUnit::Usec => 1,
            SleepUnit::Msec => 1000,
            SleepUnit::Sec => 1000000,
        }
    }
}

#[derive(Clone, Debug, PartialEq)]
pub enum LdsValue {
    Values(Vec<Rd>),
    Chars(String),
}

#[derive(Debug)]
pub enum BuiltinOp {
    /// Do nothing (costs one cycle)
    Nop,
    /// Stop execution
    Halt,
    /// Sleep
    Sleep {
        count: Rd,
        unit_us: SleepUnit,
    },
    /// Mark a jump target.
    Label(Label),
    /// Jump to a label
    Jump(Label),
    /// Mark a far jump target (can be jumped to from another routine).
    /// This label is preserved in optimized code.
    FarLabel(Label),
    /// Jump to a label that can be in another function
    FarJump(Label),
    /// Call a routine with arguments.
    /// The arguments are passed as argX. Return values are stored in resX registers.
    Call(RoutineName, Vec<Rd>),
    /// Exit the current routine with return values
    Ret(Vec<Rd>),
    /// Mark a routine entry point (call target).
    /// The RoutineName struct includes its arity
    Routine(RoutineName),
    /// Skip backward or forward. The skip count can be defined by an argument.
    Skip(Rd),
    /// Deny jumps, skips and run across this address, producing a run-time fault.
    Barrier {
        kind: Barrier,
        msg: Option<DebugMsg>,
    },
    /// Generate a run-time fault with a debugger message
    Fault(Option<DebugMsg>),
    /// Deallocate an extension object.
    /// The object is released and the handle becomes invalid.
    Delete(RdObj),
    /// Move a value
    Move { dst: Wr, src: Rd },
    /// Move lower 32 bits
    Move32 { dst: RdWr, src: Rd },
    /// Move lower 16 bits
    Move16 { dst: RdWr, src: Rd },
    /// Move lower 8 bits
    Move8 { dst: RdWr, src: Rd },
    /// Move N values
    MoveMultiple { dst: Wr, src: Rd, count: Rd },
    /// Move values from a string or integer list
    MoveSequence { dst: Wr, value: LdsValue },
    /// Swap two registers
    Exchange { a: RdWr, b: RdWr },
    /// Store runtime status to a register
    StoreFlags { dst: Wr },
    /// Load runtime status from a register
    LoadFlags { src: Rd },
}

impl BuiltinOp {
    pub fn into_op(self: BuiltinOp, pos: SourcePosition) -> Op {
        Op {
            kind: self.into(),
            pos,
            cond: None,
        }
    }
}

impl From<BuiltinOp> for OpKind {
    fn from(bo: BuiltinOp) -> Self {
        OpKind::BuiltIn(bo)
    }
}