use fix_error::Error;
use fix_runtime::{
    BytecodeReader, Machine, MachineExt, Path, Step, StrictValue, Value, VmRuntimeCtx,
    VmRuntimeCtxExt, canon_path_str,
};
use gc_arena::Mutation;

pub fn to_path<'gc, M: Machine<'gc>>(
    m: &mut M,
    ctx: &mut impl VmRuntimeCtx,
    reader: &mut BytecodeReader<'_>,
    mc: &Mutation<'gc>,
) -> Step {
    // coerce to path THEN TO STRING
    let val = m.force_and_retry::<StrictValue>(reader, mc)?;
    if let Some(Path(s)) = val.downcast::<Path>() {
        return m.return_from_primop(Value::new(s), reader);
    }
    let Some(s) = ctx.get_string(val) else {
        return m.finish_err(Error::eval_error(format!(
            "cannot coerce {} to a path",
            val.ty()
        )));
    };
    if !s.starts_with('/') {
        return m.finish_err(Error::eval_error(format!(
            "string '{s}' doesn't represent an absolute path"
        )));
    }
    let canon = canon_path_str(s);
    let sid = ctx.intern_string(canon);
    m.return_from_primop(Value::new(sid), reader)
}

pub fn is_path<'gc, M: Machine<'gc>>(
    m: &mut M,
    reader: &mut BytecodeReader<'_>,
    mc: &Mutation<'gc>,
) -> Step {
    let val = m.force_and_retry::<StrictValue>(reader, mc)?;
    let is_path = val.is::<Path>();
    m.return_from_primop(Value::new(is_path), reader)
}