import { expect, test } from "bun:test"
import { Service, type EnsureReason } from "../src/promise/service"
import {
  catchesSigterm,
  expectNotListening,
  serviceFixture,
  stopSignal,
  stoppedExitCode,
} from "./fixture/service-fixture"
import { accelerate } from "./fixture/service-timing"

const ensure = accelerate(Service.ensure)
const stop = accelerate(Service.stop)

test("discovers a registered service", async () => {
  await using fixture = await serviceFixture()
  const registration = fixture.registration
  fixture.spawn("graceful")
  await fixture.waitForFile()

  expect(await Service.discover({ file: registration, version: "test" })).toEqual(
    expect.objectContaining({ url: expect.stringMatching(/^http:\/\//) }),
  )
  expect(await Service.discover({ file: registration, version: "other" })).toBeUndefined()
})

test("discovers a compatible registered service", async () => {
  await using fixture = await serviceFixture()
  const registration = fixture.registration
  fixture.spawn("compatible")
  await fixture.waitForFile()

  expect(await Service.discover({ file: registration, version: "2.1.0" })).toBeUndefined()
  expect(await Service.discover({ file: registration, version: "2.1.0-next.1" })).toEqual(
    expect.objectContaining({ url: expect.stringMatching(/^http:\/\//) }),
  )
  expect(await Service.discover({ file: registration, version: (version) => version.startsWith("2.") })).toEqual(
    expect.objectContaining({ url: expect.stringMatching(/^http:\/\//) }),
  )
  expect(await Service.discover({ file: registration, version: (version) => version.startsWith("3.") })).toBeUndefined()
})

test("ensures a missing service with native promises", async () => {
  await using fixture = await serviceFixture()
  const registration = fixture.registration
  const starts: EnsureReason[] = []

  const endpoint = await ensure({
    file: registration,
    version: "test",
    command: fixture.command("coordinated"),
    onStart: (reason) => starts.push(reason),
  })
  const info = await Bun.file(registration).json()
  fixture.track(info.pid)

  expect(endpoint.url).toBe(info.url)
  expect(starts).toEqual(["missing"])
})

test("adds configured environment variables with native promises", async () => {
  await using fixture = await serviceFixture()
  const registration = fixture.registration
  const endpoint = await ensure({
    file: registration,
    version: "test",
    command: fixture.command("environment"),
    env: { OPENCODE_SERVICE_ENV_TEST: "configured" },
  })
  const info = await Bun.file(registration).json()
  fixture.track(info.pid)

  expect(endpoint.url).toBe(info.url)
  expect(await Bun.file(registration + ".environment").text()).toBe("configured")
})

test("passes the prepared handoff to the replacement server", async () => {
  await using fixture = await serviceFixture()
  const registration = fixture.registration
  fixture.spawn("handoff")
  await fixture.waitForFile()
  await ensure({
    file: registration,
    version: "test",
    command: fixture.command("environment"),
    env: { OPENCODE_PTY_HANDOFF: "must-not-inherit" },
  })
  const replacement = await Bun.file(registration).json()
  fixture.track(replacement.pid)

  expect(await Bun.file(registration + ".handoff").json()).toEqual(await Bun.file(registration + ".prepared").json())
  expect(await Bun.file(registration + ".pty-handoff").exists()).toBe(false)
})

test("waits for a live contender when another native contender fails", async () => {
  await using fixture = await serviceFixture()
  const registration = fixture.registration

  const endpoint = await ensure({
    file: registration,
    version: "test",
    command: fixture.command("coordinated-failed-loser", "300"),
  })
  const info = await Bun.file(registration).json()
  fixture.track(info.pid)

  expect(endpoint.url).toBe(info.url)
})

test("reports a failed registered service", async () => {
  await using fixture = await serviceFixture()
  const registration = fixture.registration
  fixture.spawn("failed-owner")
  await fixture.waitForFile()

  await expect(ensure({ file: registration, version: "test", command: [] })).rejects.toThrow(
    "Background service failed to start",
  )
})

test("reports overlapping contender failures without recruiting replacements", async () => {
  await using fixture = await serviceFixture()
  const started = Date.now()
  const pending = ensure({ file: fixture.registration, version: "test", command: fixture.command("controlled") }).catch(
    (error: unknown) => error,
  )
  const [first, second] = await fixture.waitForStarts(2)
  await fixture.release(first, "fail")
  // Let discovery observe the exit across two accelerated spawn windows before the survivor exits.
  await Bun.sleep(450)
  await fixture.release(second, "fail")
  const error = await pending

  expect(Date.now() - started).toBeLessThan(3_000)
  expect(error).toBeInstanceOf(Error)
  if (!(error instanceof Error)) throw error
  expect(error.message).toContain("Server process exited with code 23")
  expect(error.message).toContain("storage initialization denied")
  expect(await fixture.starts()).toHaveLength(2)
})

test("retains a contender failure until the deadline while its survivor stalls", async () => {
  await using fixture = await serviceFixture()
  const started = Date.now()
  const pending = ensure({ file: fixture.registration, version: "test", command: fixture.command("controlled") }).catch(
    (error: unknown) => error,
  )
  const [first, second] = await fixture.waitForStarts(2)
  await fixture.release(first, "fail")
  const error = await pending

  expect(Date.now() - started).toBeGreaterThanOrEqual(3_000)
  expect(error).toBeInstanceOf(Error)
  if (!(error instanceof Error)) throw error
  expect(error.message).toContain("Server process exited with code 23")
  expect(error.message).toContain("storage initialization denied")
  expect(await fixture.starts()).toHaveLength(2)
  expect(() => process.kill(second, 0)).not.toThrow()
})

test("accepts a surviving contender after a failure without recruiting replacements", async () => {
  await using fixture = await serviceFixture()
  const pending = ensure({ file: fixture.registration, version: "test", command: fixture.command("controlled") })
  const [first, second] = await fixture.waitForStarts(2)
  await fixture.release(first, "fail")
  await Bun.sleep(450)
  await fixture.release(second, "ready")
  const endpoint = await pending

  expect((await Service.discover({ file: fixture.registration, version: "test" }))?.url).toBe(endpoint.url)
  expect((await Bun.file(fixture.registration).json()).pid).toBe(second)
  expect(await fixture.starts()).toHaveLength(2)
})

test("recovers when an unresponsive contender is evicted after a prior failure", async () => {
  await using fixture = await serviceFixture()
  const pending = ensure({ file: fixture.registration, version: "test", command: fixture.command("controlled") })
  const [first, second] = await fixture.waitForStarts(2)
  await fixture.release(second, "hang")
  await fixture.waitForFile()
  await fixture.release(first, "fail")
  const [, , third] = await fixture.waitForStarts(3)
  await fixture.release(third, "ready")
  const endpoint = await pending
  fixture.track(third)

  expect((await Service.discover({ file: fixture.registration, version: "test" }))?.url).toBe(endpoint.url)
  expect((await Bun.file(fixture.registration).json()).pid).toBe(third)
})

test("reports a bounded contender stderr tail with native promises", async () => {
  await using fixture = await serviceFixture()
  const registration = fixture.registration
  const error = await Service.ensure({
    file: registration,
    version: "test",
    command: fixture.command("stderr-failed"),
  }).catch((error: unknown) => error)

  expect(error).toBeInstanceOf(Error)
  if (!(error instanceof Error)) throw error
  expect(error.message).toContain("actionable startup failure")
  expect(error.message.length).toBeLessThan(9_000)
}, 10_000)

test("evicts an unresponsive registered service before starting its replacement", async () => {
  await using fixture = await serviceFixture()
  const registration = fixture.registration
  const existing = fixture.spawn("hanging")
  await fixture.waitForFile()
  const original = await Bun.file(registration).json()

  const endpoint = await ensure({
    file: registration,
    version: "test",
    command: fixture.command("delayed", "10"),
  })
  const replacement = await Bun.file(registration).json()
  fixture.track(replacement.pid)

  expect((await Bun.file(registration + ".requests").text()).trim().split("\n")).toHaveLength(3)
  expect(await existing.exited).toBe(stoppedExitCode)
  expect(replacement.pid).not.toBe(original.pid)
  expect(endpoint.url).toBe(replacement.url)
})

test("recovers when the starting service it waits for is stopped", async () => {
  await using fixture = await serviceFixture()
  const registration = fixture.registration
  const starting = fixture.spawn("starting")
  await fixture.waitForFile()
  const result = ensure({ file: registration, version: "test", command: fixture.command("delayed", "10") })

  await fixture.waitForFile(registration + ".status-request")
  await stop({ file: registration })
  const endpoint = await result
  const replacement = await Bun.file(registration).json()
  fixture.track(replacement.pid)

  expect(await starting.exited).toBe(stoppedExitCode)
  expect(replacement.pid).not.toBe(starting.pid)
  expect(endpoint.url).toBe(replacement.url)
})

test("replaces a crashed service whose registration names a dead process", async () => {
  await using fixture = await serviceFixture()
  const registration = fixture.registration
  const crashed = fixture.spawn("graceful")
  await fixture.waitForFile()
  crashed.kill("SIGKILL")
  await crashed.exited

  const starts: EnsureReason[] = []
  const endpoint = await ensure({
    file: registration,
    version: "test",
    command: fixture.command("delayed", "10"),
    onStart: (reason) => starts.push(reason),
  })
  const replacement = await Bun.file(registration).json()
  fixture.track(replacement.pid)

  expect(replacement.pid).not.toBe(crashed.pid)
  expect(endpoint.url).toBe(replacement.url)
  expect(starts).toEqual(["missing"])
})

test("stops the registered service even when terminal handoff fails", async () => {
  await using fixture = await serviceFixture()
  const registration = fixture.registration
  fixture.spawn("handoff-broken")
  await fixture.waitForFile()

  await Service.stop({ file: registration, pty: "handoff" })

  expect(await fixture.signal()).toBe(stopSignal)
  expect(await Bun.file(registration).exists()).toBe(false)
  expect((await Bun.file(registration + ".pty-handoff").json()).handoff).toBeNull()
})

test("signals the registered service process", async () => {
  await using fixture = await serviceFixture()
  const registration = fixture.registration
  fixture.spawn("graceful")
  await fixture.waitForFile()

  await Service.stop({ file: registration })

  expect(await fixture.signal()).toBe(stopSignal)
  expect(await Bun.file(registration).exists()).toBe(false)
})

test("stop escalates when the registration disappears before the process exits", async () => {
  await using fixture = await serviceFixture()
  const registration = fixture.registration
  const existing = fixture.spawn("lingering", "5000")
  await fixture.waitForFile()
  const original = await Bun.file(registration).json()

  await stop({ file: registration })

  expect(await fixture.signal()).toBe(stopSignal)
  expect(() => process.kill(original.pid, 0)).toThrow()
  await expectNotListening(original.url)
  expect(await Bun.file(registration).exists()).toBe(false)
  await existing.exited
}, 15_000)

test.skipIf(process.platform === "win32")(
  "stop fails when the process survives SIGKILL",
  async () => {
    await using fixture = await serviceFixture()
    const registration = fixture.registration
    fixture.spawnUnreaped("lingering", "60000")
    await fixture.waitForFile()
    const original = await Bun.file(registration).json()

    await expect(stop({ file: registration })).rejects.toThrow(`Server process ${original.pid} is still running`)
    expect(await Bun.file(registration + ".signal").text()).toBe("SIGTERM")
  },
  15_000,
)

// On Windows the original process cannot outlive SIGTERM, so no successor can register before it exits.
test.skipIf(!catchesSigterm)(
  "stop waits for the original process while preserving a newly registered successor",
  async () => {
    await using fixture = await serviceFixture()
    const registration = fixture.registration
    const existing = fixture.spawn("lingering", "15000")
    await fixture.waitForFile()
    const original = await Bun.file(registration).json()
    // Default timing keeps the grace period open long enough for the successor to register first.
    const stopping = Service.stop({ file: registration })

    try {
      await fixture.waitForFile(registration + ".unregistered")
      const successor = fixture.spawn("graceful")
      await fixture.waitForFile()
      const replacement = await Bun.file(registration).json()
      expect(existing.exitCode).toBe(null)
      expect(replacement.pid).toBe(successor.pid)

      await stopping

      expect(() => process.kill(original.pid, 0)).toThrow()
      await expectNotListening(original.url)
      expect(await Bun.file(registration).json()).toEqual(replacement)
      expect(await fetch(new URL("/api/info", replacement.url)).then((response) => response.json())).toMatchObject({
        pid: successor.pid,
      })
      expect(successor.exitCode).toBe(null)
    } finally {
      existing.kill("SIGKILL")
      await stopping
    }
  },
  20_000,
)