import { formatModelRef } from "../../src/shared/model";
import { COMPACTION_OVERRIDE_ENTRY, type SessionModelOverride } from "./types";

export function normalizeSessionOverride(input: unknown): SessionModelOverride | null {
  if (!input || typeof input !== "object") return null;
  const mode = (input as any).mode;

  if (mode === "auto" || mode === "current") {
    return { mode };
  }

  if (mode === "model" && typeof (input as any).reference === "string" && (input as any).reference.trim()) {
    return { mode: "model", reference: (input as any).reference.trim() };
  }

  return null;
}

export function restoreSessionOverride(sessionManager: { getEntries(): any[] }): SessionModelOverride | null {
  const entries = sessionManager.getEntries();
  for (let i = entries.length - 1; i >= 0; i--) {
    const entry = entries[i];
    if (entry.type !== "custom" || entry.customType !== COMPACTION_OVERRIDE_ENTRY) continue;
    const override = normalizeSessionOverride(entry.data);
    if (override) return override;
  }
  return null;
}

export function describeSessionOverride(override: SessionModelOverride | null): string {
  if (!override || override.mode === "auto") return "auto";
  if (override.mode === "current") return "current-model";
  return override.reference;
}

export function describeEffectiveModel(model: unknown): string {
  const ref = formatModelRef(model);
  return ref || "(none)";
}