// BarrierHandlerBox - Memory barrier instruction handler
// Handles: barrier (memory fence for ordering guarantees)

using selfhost.vm.boxes.result_box as Result
using selfhost.vm.hakorune-vm.json_field_extractor as JsonFieldExtractor

static box BarrierHandlerBox {
  // Handle barrier instruction
  // inst_json: {"op":"barrier","op_kind":"Read|Write","ptr":X}
  // regs: register MapBox
  // mem: memory MapBox
  // Returns: Result.Ok(0) or Result.Err(message)
  // Phase 1: No-op (just validate fields, actual memory barrier not implemented yet)
  handle(inst_json, regs, mem) {
    // Extract op_kind
    local kind = JsonFieldExtractor.extract_string(inst_json, "op_kind")
    if kind == null {
      return Result.Err("barrier: op_kind not found")
    }

    // Validate op_kind (must be "Read" or "Write")
    if kind != "Read" && kind != "Write" {
      return Result.Err("barrier: invalid op_kind: " + kind)
    }

    // Extract ptr (memory pointer)
    local ptr = JsonFieldExtractor.extract_int(inst_json, "ptr")
    if ptr == null {
      return Result.Err("barrier: ptr not found")
    }

    // Phase 1: No-op (just validate fields)
    // Future: Implement actual memory barrier semantics for ordering guarantees
    // - Read barrier: Ensure all preceding loads complete before subsequent loads
    // - Write barrier: Ensure all preceding stores complete before subsequent stores
    return Result.Ok(0)
  }
}
