// alias_preflight_box.hako — AliasPreflightBox
// Responsibility: Early check for using-alias heads in Stage‑1 names.
// Input: raw dotted label (e.g., "alias.something.method"), UsingResolverBox instance.
// Behavior: If dotted, verify alias head is known; otherwise print a stable one-line error and return 0.
// Non‑Responsibility: Namespace normalization or emit.

using "lang/src/compiler/pipeline_v2/using_resolver_box.hako" as UsingResolverBox
using "lang/src/compiler/pipeline_v2/regex_flow.hako" as RegexFlow

static box AliasPreflightBox {
  // Returns 1 if OK, 0 if alias head is unresolved (prints error).
  check_head(raw_label, r_state) {
    if raw_label == null { return 1 }
    if r_state == null { return 1 }
    local s = "" + raw_label
    local dot = RegexFlow.find_from(s, ".", 0)
    if dot < 0 { return 1 }
    local head = s.substring(0, dot)
    if head == null || head == "" { return 1 }
    if UsingResolverBox.resolve_namespace_alias(r_state, head) == null {
      print("[ERROR] Unresolved using alias: " + head)
      return 0
    }
    return 1
  }
}

static box AliasPreflightMain { main(args) { return 0 } }