use prometeu_bytecode::FunctionMeta;
use prometeu_bytecode::isa::core::CoreOpCode as OpCode;
use prometeu_vm::verifier::{Verifier, VerifierError};

fn enc_op(op: OpCode) -> [u8; 2] { [(op as u8), 0x00] }

#[test]
fn err_invalid_yield_with_non_empty_stack() {
    // Program:
    // 0..2: PUSH_I32 1 (imm 4 bytes)
    // 6..8: YIELD
    // 8..10: RET
    let mut code = Vec::new();
    code.extend_from_slice(&enc_op(OpCode::PushI32));
    code.extend_from_slice(&1u32.to_le_bytes());
    code.extend_from_slice(&enc_op(OpCode::Yield));
    code.extend_from_slice(&enc_op(OpCode::Ret));

    let functions = vec![FunctionMeta { code_offset: 0, code_len: code.len() as u32, return_slots: 1, ..Default::default() }];
    let res = Verifier::verify(&code, &functions);
    assert_eq!(res, Err(VerifierError::InvalidYieldContext { pc: 6, height: 1 }));
}

#[test]
fn err_spawn_arg_mismatch() {
    // Caller at func 0: SPAWN fn_id=1, arg_count=1; RET
    // Callee at func 1: expects 2 param_slots
    let mut code = Vec::new();
    code.extend_from_slice(&enc_op(OpCode::Spawn));
    code.extend_from_slice(&1u32.to_le_bytes()); // fn_id
    code.extend_from_slice(&1u32.to_le_bytes()); // arg_count (mismatch: callee expects 2)
    code.extend_from_slice(&enc_op(OpCode::Ret));

    let caller = FunctionMeta { code_offset: 0, code_len: code.len() as u32, return_slots: 0, ..Default::default() };
    // Callee has no code here; only signature matters
    let callee = FunctionMeta { code_offset: code.len() as u32, code_len: 0, param_slots: 2, return_slots: 0, ..Default::default() };
    let functions = vec![caller, callee];

    let res = Verifier::verify(&code, &functions);
    assert_eq!(res, Err(VerifierError::BadSpawnArgCount { pc: 0, expected: 2, got: 1 }));
}

#[test]
fn err_sleep_truncated_immediate() {
    // Encode SLEEP but provide only 1 of 4 immediate bytes
    let mut code = Vec::new();
    code.extend_from_slice(&enc_op(OpCode::Sleep));
    code.push(0xAB);
    let functions = vec![FunctionMeta { code_offset: 0, code_len: code.len() as u32, ..Default::default() }];
    let res = Verifier::verify(&code, &functions);
    assert_eq!(
        res,
        Err(VerifierError::TruncatedImmediate { pc: 0, opcode: OpCode::Sleep, need: 4, have: 1 })
    );
}