import { describe, expect, test } from "bun:test";

import { repairHistory } from "../agent/history-repair/history-repair.js";
import type { Message } from "../providers/types.js";

describe("history-repair observability", () => {
  test("stats are all zero for valid history (no logs should be emitted)", () => {
    const messages: Message[] = [
      { role: "user", content: [{ type: "text", text: "Hello" }] },
      { role: "assistant", content: [{ type: "text", text: "Hi" }] },
    ];

    const { stats } = repairHistory(messages);

    expect(stats.assistantToolResultsMigrated).toBe(0);
    expect(stats.missingToolResultsInserted).toBe(0);
    expect(stats.orphanToolResultsDowngraded).toBe(0);
    expect(stats.consecutiveSameRoleMerged).toBe(0);
  });

  test("stats are non-zero only when repairs are applied", () => {
    const messages: Message[] = [
      { role: "user", content: [{ type: "text", text: "Go" }] },
      {
        role: "assistant",
        content: [
          { type: "tool_use", id: "tu_1", name: "bash", input: {} },
          { type: "tool_result", tool_use_id: "tu_bad", content: "stale" },
        ],
      },
      {
        role: "user",
        content: [
          { type: "tool_result", tool_use_id: "tu_orphan", content: "orphan" },
        ],
      },
    ];

    const { stats } = repairHistory(messages);

    // assistantToolResultsMigrated: 1 (tu_bad migrated from assistant message)
    expect(stats.assistantToolResultsMigrated).toBe(1);
    // missingToolResultsInserted: 1 (tu_1 had no matching result in next user msg)
    // but actually the orphan tu_orphan is downgraded, and tu_1 is injected
    expect(stats.missingToolResultsInserted).toBe(1);
    // orphanToolResultsDowngraded: 1 (tu_orphan doesn't match tu_1)
    expect(stats.orphanToolResultsDowngraded).toBe(1);

    // All counters > 0 → log would be emitted
    const shouldLog =
      stats.assistantToolResultsMigrated > 0 ||
      stats.missingToolResultsInserted > 0 ||
      stats.orphanToolResultsDowngraded > 0 ||
      stats.consecutiveSameRoleMerged > 0;
    expect(shouldLog).toBe(true);
  });
});