import std/[os, osproc, strutils, tempfiles, unittest]
import ../src/namespaced_logging
import ./ownership

type
  CloneControl = object
    failNext: bool
  FallibleAppender = ref object of LogAppender
    control: ptr CloneControl

method clone(app: FallibleAppender): LogAppender {.gcsafe.} =
  if app.control.failNext:
    app.control.failNext = false
    raise newException(ValueError, "injected clone failure")
  FallibleAppender(control: app.control)

type
  LifetimeProbeObj = object
    destroyed: ptr int
  LifetimeProbe = SharedLogState[LifetimeProbeObj]

proc `=destroy`(probe: LifetimeProbeObj) =
  if probe.destroyed != nil:
    inc probe.destroyed[]

proc ignoreMessage(state: var LifetimeProbe, msg: LogMessage) {.gcsafe, noconv.} =
  discard

proc watchedService(destroyed: ptr int): LogService =
  result = initLogService()
  result.addAppender(initCustomLogAppender(
    initSharedLogState(LifetimeProbeObj(destroyed: destroyed)), ignoreMessage))

proc createAndReleaseService(destroyed: ptr int) =
  var service = watchedService(destroyed)
  service.setThreshold("worker", lvlInfo)
  # All owning handles leave scope here. No thread or cycle is involved.

suite "ORC service handle lifetime":
  test "copy, self-assignment, replacement, and move retain exactly one lifetime":
    var firstDestroyed, replacedDestroyed = 0
    block:
      var first = watchedService(addr firstDestroyed)
      var other = watchedService(addr replacedDestroyed)
      other = first
      check replacedDestroyed == 1
      first = first
      first = LogService()
      check firstDestroyed == 0

      var moved = move(other)
      expect ValueError:
        discard other.threadLocalRef()
      moved.setThreshold("worker", lvlInfo)
      let local = moved.threadLocalRef()
      moved = LogService()
      check firstDestroyed == 0
      check local.getLogger("worker").isEnabled(lvlInfo)
    check firstDestroyed == 1
    check replacedDestroyed == 1

  test "handles embedded in copied containers retain the service":
    var destroyed = 0
    block:
      var source = watchedService(addr destroyed)
      var handles = @[source, source]
      var copied = handles
      source = LogService()
      handles.setLen(0)
      check destroyed == 0
      copied[0].setThreshold("worker", lvlWarn)
      let local = copied[1].threadLocalRef()
      check not local.getLogger("worker").isEnabled(lvlInfo)
      copied.setLen(0)
      check destroyed == 0
    check destroyed == 1

  test "an exported handle outlives the local service it came from":
    var destroyed = 0
    block:
      var exported: LogService
      block:
        let local = watchedService(addr destroyed).threadLocalRef()
        exported = local.service
      check destroyed == 0
      check exported.threadLocalRef().getLogger("worker").isEnabled(lvlInfo)
    check destroyed == 1

  test "failed local construction releases its shared owner and partial cache":
    var destroyed = 0
    var control: CloneControl
    block:
      var service = watchedService(addr destroyed)
      service.addAppender(FallibleAppender(control: addr control))
      control.failNext = true
      expect ValueError:
        discard service.threadLocalRef()
      check destroyed == 0
    check destroyed == 1

suite "ORC ownership and configuration regressions":
  test "isEnabled observes a namespace change before any log call":
    var service = initLogService()
    service.setThreshold("worker", lvlError)
    let local = service.threadLocalRef()
    let logger = local.getLogger("worker")
    check not logger.isEnabled(lvlInfo)

    # Simulate a change from another service handle without introducing a
    # reference-count race into this deterministic configuration test.
    service.setThreshold("worker", lvlInfo)
    check logger.isEnabled(lvlInfo)

  test "a failed refresh is retried without another configuration change":
    var control: CloneControl
    var service = initLogService()
    service.addAppender(FallibleAppender(control: addr control))
    let local = service.threadLocalRef()
    discard local.getLogger("worker")
    service.setRootThreshold(lvlInfo)

    control.failNext = true
    expect ValueError:
      local.ensureFreshness()

    # clone now succeeds; the failed refresh must not have marked the
    # incomplete local configuration as current.
    local.ensureFreshness()
    check local.appenders().len == 1

  test "releasing the service releases state owned by its appenders":
    var destroyed = 0
    createAndReleaseService(addr destroyed)
    check destroyed == 1

suite "Background writer shutdown regressions":
  for destination in ["file", "console", "stderr", "file-empty", "console-empty",
                      "files", "file-parallel", "console-parallel"]:
    test destination & " writer drains accepted messages at normal process exit":
      let directory = createTempDir("namespaced_logging_shutdown_", "")
      let outputPath = directory / "messages.log"
      defer: removeDir(directory)

      let child = startProcess(parentDir(getAppFilename()) / "writer_child",
        args = [destination, outputPath], options = {poParentStreams})
      defer: close(child)
      let exitCode = child.waitForExit(15_000)
      if exitCode == -1:
        child.kill()
        discard child.waitForExit()
      check exitCode == 0
      require fileExists(outputPath)

      if destination.endsWith("-parallel"):
        let received = readFile(outputPath).splitLines()
        require received.len == 10_001
        var next = [0, 2_500, 5_000, 7_500]
        for line in received[0 ..< 10_000]:
          require line.startsWith("message ")
          let number = parseInt(line[8 .. ^1])
          require number in 0 ..< 10_000
          let worker = number div 2_500
          check number == next[worker]
          inc next[worker]
        check next == [2_500, 5_000, 7_500, 10_000]
      else:
        var expected: string
        for i in 0 ..< 10_000:
          if destination == "file-empty" and i mod 128 == 0:
            expected.add("\n")
          expected.add("message " & $i & "\n")
        check readFile(outputPath) == expected
        if destination == "files":
          require fileExists(outputPath & ".second")
          check readFile(outputPath & ".second") == expected