openchamber/packages/ui/src/sync/__tests__/event-reducer.test.ts

import { describe, expect, test } from "bun:test"
import type { Event, Part } from "@opencode-ai/sdk/v2/client"
import { applyDirectoryEvent } from "../event-reducer"
import { INITIAL_STATE, type State } from "../types"

function state(overrides: Partial<State> = {}): State {
  return {
    ...INITIAL_STATE,
    message: {},
    part: {},
    ...overrides,
  }
}

function deltaEvent(): Event {
  return {
    type: "message.part.delta",
    properties: {
      messageID: "msg_1",
      partID: "prt_1",
      field: "text",
      delta: "hello",
    },
  } as Event
}

function partUpdatedEvent(): Event {
  return {
    type: "message.part.updated",
    properties: {
      part: {
        id: "prt_1",
        messageID: "msg_1",
        sessionID: "ses_1",
        type: "text",
        text: "hello",
      },
    },
  } as Event
}

describe("applyDirectoryEvent", () => {
  test("returns typed materialization when delta arrives before parts", () => {
    const result = applyDirectoryEvent(state(), deltaEvent())

    expect(result).toEqual({
      changed: false,
      materialization: { type: "incomplete-session-snapshot", messageID: "msg_1", partID: "prt_1" },
    })
  })

  test("returns typed materialization when delta part is missing", () => {
    const result = applyDirectoryEvent(
      state({ part: { msg_1: [{ id: "prt_2", messageID: "msg_1", type: "text", text: "" } as Part] } }),
      deltaEvent(),
    )

    expect(result).toEqual({
      changed: false,
      materialization: { type: "incomplete-session-snapshot", messageID: "msg_1", partID: "prt_1" },
    })
  })

  test("applies part update and requests materialization when owning message is absent", () => {
    const draft = state()
    const result = applyDirectoryEvent(draft, partUpdatedEvent())

    expect(draft.part.msg_1.map((item) => item.id)).toEqual(["prt_1"])
    expect(result).toEqual({
      changed: true,
      materialization: {
        type: "incomplete-session-snapshot",
        sessionID: "ses_1",
        messageID: "msg_1",
        partID: "prt_1",
      },
    })
  })

  test("applies part update without materialization when owning message exists", () => {
    const draft = state({
      message: { ses_1: [{ id: "msg_1", sessionID: "ses_1", role: "assistant", time: { created: 1 } } as never] },
    })
    const result = applyDirectoryEvent(draft, partUpdatedEvent())

    expect(draft.part.msg_1.map((item) => item.id)).toEqual(["prt_1"])
    expect(result).toBe(true)
  })
})