/**
 * Test: before_compaction & after_compaction hook wiring
 */
import { beforeEach, describe, expect, it, vi } from "vitest";
import { makeZeroUsageSnapshot } from "../agents/usage.js";

const hookMocks = vi.hoisted(() => ({
  runner: {
    hasHooks: vi.fn(() => false),
    runBeforeCompaction: vi.fn(async () => {}),
    runAfterCompaction: vi.fn(async () => {}),
  },
  emitAgentEvent: vi.fn(),
}));

describe("compaction hook wiring", () => {
  let handleAutoCompactionStart: typeof import("../agents/pi-embedded-subscribe.handlers.compaction.js").handleAutoCompactionStart;
  let handleAutoCompactionEnd: typeof import("../agents/pi-embedded-subscribe.handlers.compaction.js").handleAutoCompactionEnd;

  beforeEach(async () => {
    vi.resetModules();
    hookMocks.runner.hasHooks.mockClear();
    hookMocks.runner.hasHooks.mockReturnValue(false);
    hookMocks.runner.runBeforeCompaction.mockClear();
    hookMocks.runner.runBeforeCompaction.mockResolvedValue(undefined);
    hookMocks.runner.runAfterCompaction.mockClear();
    hookMocks.runner.runAfterCompaction.mockResolvedValue(undefined);
    hookMocks.emitAgentEvent.mockClear();
    vi.doMock("../plugins/hook-runner-global.js", () => ({
      getGlobalHookRunner: () => hookMocks.runner,
    }));
    vi.doMock("../infra/agent-events.js", () => ({
      emitAgentEvent: hookMocks.emitAgentEvent,
    }));
    ({ handleAutoCompactionStart, handleAutoCompactionEnd } =
      await import("../agents/pi-embedded-subscribe.handlers.compaction.js"));
  });

  function createCompactionEndCtx(params: {
    runId: string;
    messages?: unknown[];
    sessionFile?: string;
    sessionKey?: string;
    compactionCount?: number;
    withRetryHooks?: boolean;
  }) {
    return {
      params: {
        runId: params.runId,
        sessionKey: params.sessionKey,
        session: {
          messages: params.messages ?? [],
          sessionFile: params.sessionFile,
        },
      },
      state: { compactionInFlight: true },
      log: { debug: vi.fn(), warn: vi.fn() },
      maybeResolveCompactionWait: vi.fn(),
      incrementCompactionCount: vi.fn(),
      getCompactionCount: () => params.compactionCount ?? 0,
      ...(params.withRetryHooks
        ? {
            noteCompactionRetry: vi.fn(),
            resetForCompactionRetry: vi.fn(),
          }
        : {}),
    };
  }

  it("calls runBeforeCompaction in handleAutoCompactionStart", () => {
    hookMocks.runner.hasHooks.mockReturnValue(true);

    const ctx = {
      params: {
        runId: "r1",
        sessionKey: "agent:main:web-abc123",
        session: { messages: [1, 2, 3], sessionFile: "/tmp/test.jsonl" },
        onAgentEvent: vi.fn(),
      },
      state: { compactionInFlight: false },
      log: { debug: vi.fn(), warn: vi.fn() },
      incrementCompactionCount: vi.fn(),
      ensureCompactionPromise: vi.fn(),
    };

    handleAutoCompactionStart(ctx as never);

    expect(hookMocks.runner.runBeforeCompaction).toHaveBeenCalledTimes(1);

    const beforeCalls = hookMocks.runner.runBeforeCompaction.mock.calls as unknown as Array<
      [unknown, unknown]
    >;
    const event = beforeCalls[0]?.[0] as
      | { messageCount?: number; messages?: unknown[]; sessionFile?: string }
      | undefined;
    expect(event?.messageCount).toBe(3);
    expect(event?.messages).toEqual([1, 2, 3]);
    expect(event?.sessionFile).toBe("/tmp/test.jsonl");
    const hookCtx = beforeCalls[0]?.[1] as { sessionKey?: string } | undefined;
    expect(hookCtx?.sessionKey).toBe("agent:main:web-abc123");
    expect(ctx.ensureCompactionPromise).toHaveBeenCalledTimes(1);
    expect(hookMocks.emitAgentEvent).toHaveBeenCalledWith({
      runId: "r1",
      stream: "compaction",
      data: { phase: "start" },
    });
    expect(ctx.params.onAgentEvent).toHaveBeenCalledWith({
      stream: "compaction",
      data: { phase: "start" },
    });
  });

  it("calls runAfterCompaction when willRetry is false", () => {
    hookMocks.runner.hasHooks.mockReturnValue(true);

    const ctx = createCompactionEndCtx({
      runId: "r2",
      messages: [1, 2],
      sessionFile: "/tmp/session.jsonl",
      sessionKey: "agent:main:web-xyz",
      compactionCount: 1,
    });

    handleAutoCompactionEnd(
      ctx as never,
      {
        type: "auto_compaction_end",
        willRetry: false,
        result: { summary: "compacted" },
      } as never,
    );

    expect(hookMocks.runner.runAfterCompaction).toHaveBeenCalledTimes(1);

    const afterCalls = hookMocks.runner.runAfterCompaction.mock.calls as unknown as Array<
      [unknown, unknown]
    >;
    const event = afterCalls[0]?.[0] as
      | { messageCount?: number; compactedCount?: number; sessionFile?: string }
      | undefined;
    expect(event?.messageCount).toBe(2);
    expect(event?.compactedCount).toBe(1);
    expect(event?.sessionFile).toBe("/tmp/session.jsonl");
    const hookCtx = afterCalls[0]?.[1] as { sessionKey?: string } | undefined;
    expect(hookCtx?.sessionKey).toBe("agent:main:web-xyz");
    expect(ctx.incrementCompactionCount).toHaveBeenCalledTimes(1);
    expect(ctx.maybeResolveCompactionWait).toHaveBeenCalledTimes(1);
    expect(hookMocks.emitAgentEvent).toHaveBeenCalledWith({
      runId: "r2",
      stream: "compaction",
      data: { phase: "end", willRetry: false, completed: true },
    });
  });

  it("does not call runAfterCompaction when willRetry is true but still increments counter", () => {
    hookMocks.runner.hasHooks.mockReturnValue(true);

    const ctx = createCompactionEndCtx({
      runId: "r3",
      compactionCount: 1,
      withRetryHooks: true,
    });

    handleAutoCompactionEnd(
      ctx as never,
      {
        type: "auto_compaction_end",
        willRetry: true,
        result: { summary: "compacted" },
      } as never,
    );

    expect(hookMocks.runner.runAfterCompaction).not.toHaveBeenCalled();
    // Counter is incremented even with willRetry — compaction succeeded (#38905)
    expect(ctx.incrementCompactionCount).toHaveBeenCalledTimes(1);
    expect(ctx.noteCompactionRetry).toHaveBeenCalledTimes(1);
    expect(ctx.resetForCompactionRetry).toHaveBeenCalledTimes(1);
    expect(ctx.maybeResolveCompactionWait).not.toHaveBeenCalled();
    expect(hookMocks.emitAgentEvent).toHaveBeenCalledWith({
      runId: "r3",
      stream: "compaction",
      data: { phase: "end", willRetry: true, completed: true },
    });
  });

  it("does not increment counter when compaction was aborted", () => {
    const ctx = createCompactionEndCtx({ runId: "r3b" });

    handleAutoCompactionEnd(
      ctx as never,
      {
        type: "auto_compaction_end",
        willRetry: false,
        result: undefined,
        aborted: true,
      } as never,
    );

    expect(ctx.incrementCompactionCount).not.toHaveBeenCalled();
  });

  it("does not increment counter when compaction has result but was aborted", () => {
    const ctx = createCompactionEndCtx({ runId: "r3b2" });

    handleAutoCompactionEnd(
      ctx as never,
      {
        type: "auto_compaction_end",
        willRetry: false,
        result: { summary: "compacted" },
        aborted: true,
      } as never,
    );

    expect(ctx.incrementCompactionCount).not.toHaveBeenCalled();
  });

  it("does not increment counter when result is undefined", () => {
    const ctx = createCompactionEndCtx({ runId: "r3c" });

    handleAutoCompactionEnd(
      ctx as never,
      {
        type: "auto_compaction_end",
        willRetry: false,
        result: undefined,
        aborted: false,
      } as never,
    );

    expect(ctx.incrementCompactionCount).not.toHaveBeenCalled();
  });

  it("resets stale assistant usage after final compaction", () => {
    const messages = [
      { role: "user", content: "hello" },
      {
        role: "assistant",
        content: "response one",
        usage: { totalTokens: 180_000, input: 100, output: 50 },
      },
      {
        role: "assistant",
        content: "response two",
        usage: { totalTokens: 181_000, input: 120, output: 60 },
      },
    ];

    const ctx = {
      params: { runId: "r4", session: { messages } },
      state: { compactionInFlight: true },
      log: { debug: vi.fn(), warn: vi.fn() },
      maybeResolveCompactionWait: vi.fn(),
      getCompactionCount: () => 1,
      incrementCompactionCount: vi.fn(),
    };

    handleAutoCompactionEnd(
      ctx as never,
      {
        type: "auto_compaction_end",
        willRetry: false,
        result: { summary: "compacted" },
      } as never,
    );

    const assistantOne = messages[1] as { usage?: unknown };
    const assistantTwo = messages[2] as { usage?: unknown };
    expect(assistantOne.usage).toEqual(makeZeroUsageSnapshot());
    expect(assistantTwo.usage).toEqual(makeZeroUsageSnapshot());
  });

  it("does not clear assistant usage while compaction is retrying", () => {
    const messages = [
      {
        role: "assistant",
        content: "response",
        usage: { totalTokens: 184_297, input: 130_000, output: 2_000 },
      },
    ];

    const ctx = {
      params: { runId: "r5", session: { messages } },
      state: { compactionInFlight: true },
      log: { debug: vi.fn(), warn: vi.fn() },
      noteCompactionRetry: vi.fn(),
      resetForCompactionRetry: vi.fn(),
      getCompactionCount: () => 0,
    };

    handleAutoCompactionEnd(
      ctx as never,
      {
        type: "auto_compaction_end",
        willRetry: true,
      } as never,
    );

    const assistant = messages[0] as { usage?: unknown };
    expect(assistant.usage).toEqual({ totalTokens: 184_297, input: 130_000, output: 2_000 });
  });
});
