box::use(
  testthat[
    expect_equal,
    expect_error,
    expect_false,
    expect_length,
    expect_match,
    expect_null,
    expect_output,
    expect_true,
    skip_if,
    skip_if_not_installed,
    test_that
  ]
)

# `resolve_worker_count()` reads its environment; pin every input so the
# assertions hold regardless of the machine, and lift the R CMD check core cap
# (`_R_CHECK_LIMIT_CORES_`) that would otherwise clamp the result to 2.
worker_count <- function(n_tasks, is_interactive = FALSE, os_type = "unix", n_cores = 8L) {
  box::use(artma / modules / method_execution[resolve_worker_count])

  resolve_worker_count(
    n_tasks,
    is_interactive = is_interactive,
    os_type = os_type,
    n_cores = n_cores,
    max_workers = Inf,
    graphics_fork_safe = TRUE
  )
}

can_fork <- function() {
  cores <- tryCatch(parallel::detectCores(), error = function(err) NA_integer_)
  !identical(.Platform$OS.type, "windows") && is.numeric(cores) && !is.na(cores) && cores >= 2L
}

test_that("group_methods_into_layers puts independent methods in one layer", {
  box::use(artma / modules / method_execution[group_methods_into_layers])

  layers <- group_methods_into_layers(c("a", "b", "c"), list())

  expect_length(layers, 1L)
  expect_equal(layers[[1L]], c("a", "b", "c"))
})

test_that("group_methods_into_layers separates dependents into later layers", {
  box::use(artma / modules / method_execution[group_methods_into_layers])

  layers <- group_methods_into_layers(
    c("bma", "funnel_plot", "best_practice_estimate"),
    list(best_practice_estimate = "bma")
  )

  expect_length(layers, 2L)
  expect_equal(layers[[1L]], c("bma", "funnel_plot"))
  expect_equal(layers[[2L]], "best_practice_estimate")
})

test_that("group_methods_into_layers chains transitive dependencies", {
  box::use(artma / modules / method_execution[group_methods_into_layers])

  layers <- group_methods_into_layers(
    c("a", "b", "c"),
    list(b = "a", c = "b")
  )

  expect_equal(layers, list("a", "b", "c"))
})

test_that("group_methods_into_layers ignores dependencies outside the requested set", {
  box::use(artma / modules / method_execution[group_methods_into_layers])

  layers <- group_methods_into_layers(c("fma"), list(fma = "bma"))

  expect_equal(layers, list("fma"))
})

test_that("group_methods_into_layers handles the empty case and aborts on cycles", {
  box::use(artma / modules / method_execution[group_methods_into_layers])

  expect_equal(group_methods_into_layers(character(), list()), list())
  expect_error(
    group_methods_into_layers(c("a", "b"), list(a = "b", b = "a")),
    "Cyclic"
  )
})

test_that("group_methods_into_layers flattens to a valid topological order", {
  box::use(
    artma / modules / method_execution[group_methods_into_layers],
    artma / modules / runtime_methods[topo_sort_methods]
  )

  names <- c("bma", "fma", "best_practice_estimate")
  deps <- list(best_practice_estimate = "bma", fma = "bma")

  flattened <- unlist(group_methods_into_layers(topo_sort_methods(names, deps), deps))

  expect_true(which(flattened == "bma") < which(flattened == "fma"))
  expect_true(which(flattened == "bma") < which(flattened == "best_practice_estimate"))
})

test_that("resolve_worker_count falls back to sequential execution", {
  withr::local_options(list(artma.general.parallel = TRUE))

  # A single task never forks.
  expect_equal(worker_count(1L, n_cores = 8L), 1L)
  # Windows has no fork().
  expect_equal(worker_count(4L, os_type = "windows", n_cores = 8L), 1L)
  # A single core leaves nothing to parallelise over.
  expect_equal(worker_count(4L, n_cores = 1L), 1L)
  # An unknown core count is treated as unusable.
  expect_equal(worker_count(4L, n_cores = NA_integer_), 1L)
})

test_that("resolve_worker_count honours the artma.general.parallel flag", {
  withr::local_options(list(artma.general.parallel = FALSE))
  expect_equal(worker_count(4L, n_cores = 8L), 1L)

  withr::local_options(list(artma.general.parallel = TRUE))
  expect_equal(worker_count(4L, n_cores = 8L), 4L)
  expect_equal(worker_count(9L, n_cores = 4L), 3L)
})

test_that("resolve_worker_count stays sequential when methods may still prompt", {
  withr::local_options(list(artma.general.parallel = TRUE, artma.autonomy.level = "balanced"))
  expect_equal(worker_count(4L, is_interactive = TRUE, n_cores = 8L), 1L)

  withr::local_options(list(artma.autonomy.level = "autonomous"))
  expect_equal(worker_count(4L, is_interactive = TRUE, n_cores = 8L), 4L)
})

test_that("resolve_worker_count respects the environment's process ceiling", {
  box::use(artma / modules / method_execution[max_parallel_workers, resolve_worker_count])

  withr::local_options(list(artma.general.parallel = TRUE))

  # R CMD check refuses more than two simultaneous processes.
  withr::local_envvar(list("_R_CHECK_LIMIT_CORES_" = "TRUE"))
  expect_equal(max_parallel_workers(), 2L)
  expect_equal(
    resolve_worker_count(
      8L,
      is_interactive = FALSE, os_type = "unix", n_cores = 16L, graphics_fork_safe = TRUE
    ),
    2L
  )

  # Outside a check, mc.cores is the user-facing cap.
  withr::local_envvar(list("_R_CHECK_LIMIT_CORES_" = NA))
  withr::local_options(list(mc.cores = 3L))
  expect_equal(max_parallel_workers(), 3L)
  expect_equal(
    resolve_worker_count(
      8L,
      is_interactive = FALSE, os_type = "unix", n_cores = 16L, graphics_fork_safe = TRUE
    ),
    3L
  )
})

test_that("without_captured_output lets output through and still traps errors", {
  box::use(artma / modules / method_execution[without_captured_output])

  expect_output(
    outcome <- without_captured_output({
      cat("to stdout\n")
      "value"
    }),
    "to stdout"
  )
  expect_equal(outcome$value, "value")
  expect_null(outcome$error)
  expect_equal(outcome$output, character())

  failed <- without_captured_output(stop("boom"))
  expect_null(failed$value)
  expect_match(failed$error, "boom")
})

test_that("a sequential layer leaves output on the console so prompts stay visible", {
  box::use(artma / modules / method_execution[execute_method_layer])

  # A method that prompts renders its menu with cat()/cli. Sinking that output
  # hid the menu while the method blocked on a keypress, hanging the run.
  expect_output(
    outcomes <- execute_method_layer(
      "asks",
      run_one = function(name) {
        cat("Do you want to run BMA first?\n")
        name
      },
      workers = 1L
    ),
    "Do you want to run BMA first?",
    fixed = TRUE
  )

  expect_equal(outcomes[[1L]]$value, "asks")
  expect_equal(outcomes[[1L]]$output, character())
})

test_that("with_captured_output captures output instead of printing it", {
  box::use(artma / modules / method_execution[with_captured_output])

  outcome <- testthat::expect_silent(
    with_captured_output({
      cat("to stdout\n")
      message("to stderr")
      "value"
    })
  )

  expect_equal(outcome$value, "value")
  expect_null(outcome$error)
  expect_true(any(grepl("to stdout", outcome$output, fixed = TRUE)))
  expect_true(any(grepl("to stderr", outcome$output, fixed = TRUE)))
})

test_that("with_captured_output keeps cli formatting intact", {
  box::use(artma / modules / method_execution[with_captured_output])

  withr::local_options(list(cli.num_colors = 256L))

  outcome <- with_captured_output(cli::cli_alert_success("all {.strong good}"))
  captured <- paste(outcome$output, collapse = "\n")

  expect_match(captured, "all")
  # ANSI escapes survive the capture, so replaying reproduces the styling.
  expect_true(grepl("\033[", captured, fixed = TRUE))
})

test_that("with_captured_output keeps consecutive cli messages on separate lines", {
  box::use(artma / modules / method_execution[with_captured_output])

  # cli condition messages carry no trailing newline (unlike base::message()),
  # so without an explicit newline they concatenate into one line (issue #321).
  outcome <- with_captured_output({
    cli::cli_inform("first line")
    cli::cli_inform("second line")
  })

  first_idx <- grep("first line", outcome$output)
  second_idx <- grep("second line", outcome$output)
  expect_equal(length(first_idx), 1L)
  expect_equal(length(second_idx), 1L)
  expect_false(identical(first_idx, second_idx))
})

test_that("with_captured_output records errors and restores the sinks", {
  box::use(artma / modules / method_execution[with_captured_output])

  sinks_before <- sink.number()
  outcome <- with_captured_output(stop("boom"))

  expect_null(outcome$value)
  expect_equal(outcome$error, "boom")
  expect_equal(sink.number(), sinks_before)
})

test_that("build_rng_streams derives distinct, reproducible streams", {
  box::use(artma / modules / method_execution[build_rng_streams])

  streams <- build_rng_streams(c("a", "b"), seed = 42L)

  expect_equal(names(streams), c("a", "b"))
  expect_false(identical(streams$a, streams$b))
  expect_equal(streams, build_rng_streams(c("a", "b"), seed = 42L))
  expect_false(identical(streams, build_rng_streams(c("a", "b"), seed = 7L)))
})

test_that("build_rng_streams leaves the caller's RNG state untouched", {
  box::use(artma / modules / method_execution[build_rng_streams])

  set.seed(123)
  before_kind <- RNGkind()
  before_seed <- .Random.seed

  build_rng_streams(c("a", "b", "c"), seed = 1L)

  expect_equal(RNGkind(), before_kind)
  expect_equal(.Random.seed, before_seed)
})

test_that("build_rng_streams gives a method the same stream regardless of the requested set", {
  box::use(artma / modules / method_execution[build_rng_streams])

  alone <- build_rng_streams("a", seed = 42L)
  paired <- build_rng_streams(c("a", "b"), seed = 42L)
  reversed <- build_rng_streams(c("b", "a"), seed = 42L)

  # A cached stochastic result must not go stale just because a later run
  # requests a different combination of methods, so the stream is a function
  # of the seed and the method's name only.
  expect_equal(paired$a, alone$a)
  expect_equal(reversed$a, paired$a)
  expect_equal(reversed$b, paired$b)
})

test_that("method_stream_seed folds the seed and name deterministically", {
  box::use(artma / modules / method_execution[method_stream_seed])

  expect_equal(method_stream_seed(42L, "bma"), method_stream_seed(42L, "bma"))
  expect_false(method_stream_seed(42L, "bma") == method_stream_seed(42L, "fma"))
  expect_false(method_stream_seed(42L, "bma") == method_stream_seed(7L, "bma"))
  expect_true(is.integer(method_stream_seed(20240101, "bma")))
})

test_that("build_rng_streams rejects a missing seed", {
  box::use(artma / modules / method_execution[build_rng_streams])

  expect_error(build_rng_streams("a", seed = NA), "single non-missing number")
})

test_that("execute_method_layer returns results in input order", {
  box::use(artma / modules / method_execution[execute_method_layer])

  outcomes <- execute_method_layer(c("c", "a", "b"), run_one = function(name) toupper(name))

  expect_equal(vapply(outcomes, function(o) o$value, character(1)), c("C", "A", "B"))
})

test_that("execute_method_layer isolates failures from the rest of the layer", {
  box::use(artma / modules / method_execution[execute_method_layer])

  run_one <- function(name) {
    if (identical(name, "b")) stop("b exploded")
    name
  }

  for (workers in c(1L, 2L)) {
    skip_if(workers > 1L && !can_fork(), "forking is unavailable")

    outcomes <- execute_method_layer(c("a", "b", "c"), run_one = run_one, workers = workers)

    expect_equal(outcomes[[1L]]$value, "a")
    expect_null(outcomes[[2L]]$value)
    expect_match(outcomes[[2L]]$error, "b exploded")
    expect_equal(outcomes[[3L]]$value, "c")
  }
})

test_that("execute_method_layer gives identical results in parallel and sequentially", {
  box::use(artma / modules / method_execution[build_rng_streams, execute_method_layer])

  skip_if(!can_fork(), "forking is unavailable")

  names <- c("a", "b", "c")
  streams <- build_rng_streams(names, seed = 99L)
  run_one <- function(name) list(name = name, draws = stats::runif(3))

  sequential <- execute_method_layer(names, run_one, streams = streams, workers = 1L)
  concurrent <- execute_method_layer(names, run_one, streams = streams, workers = 2L)

  expect_equal(
    lapply(sequential, function(o) o$value),
    lapply(concurrent, function(o) o$value)
  )
})

test_that("describe_dead_worker never reports an empty error", {
  box::use(artma / modules / method_execution[describe_dead_worker])

  # `mclapply()` yields NULL for a child that was killed outright, which used to
  # collapse to an empty failure message.
  silent <- describe_dead_worker(NULL, "bma")
  expect_true(nzchar(silent))
  expect_match(silent, "bma", fixed = TRUE)
  expect_match(silent, "artma.general.parallel", fixed = TRUE)

  detailed <- describe_dead_worker("boom", "funnel_plot")
  expect_match(detailed, "funnel_plot", fixed = TRUE)
  expect_match(detailed, "boom", fixed = TRUE)
})

test_that("execute_method_layer explains a worker that died without an error", {
  box::use(artma / modules / method_execution[execute_method_layer])

  skip_if(!can_fork(), "forking is unavailable")

  # Guard the kill on actually being in a forked child: signalling the current
  # process would take down the testthat subprocess running this file.
  parent_pid <- Sys.getpid()
  outcomes <- suppressWarnings(execute_method_layer(
    c("a", "b"),
    run_one = function(name) {
      if (identical(name, "b") && !identical(Sys.getpid(), parent_pid)) {
        tools::pskill(Sys.getpid())
      }
      name
    },
    workers = 2L
  ))

  expect_equal(outcomes[[1L]]$value, "a")
  expect_null(outcomes[[2L]]$value)
  expect_true(nzchar(outcomes[[2L]]$error))
  expect_match(outcomes[[2L]]$error, "b", fixed = TRUE)
})

test_that("execute_method_layer pins BLAS/OpenMP to one thread only while forking", {
  box::use(artma / modules / method_execution[execute_method_layer])

  skip_if(!can_fork(), "forking is unavailable")
  skip_if_not_installed("RhpcBLASctl")
  # RhpcBLASctl reports NA for every OpenMP query when R itself was not built
  # with OpenMP support (common on macOS toolchains); there is nothing to
  # verify restored in that case, but the layer must still run correctly.
  has_omp <- !is.na(RhpcBLASctl::omp_get_max_threads())

  if (has_omp) {
    RhpcBLASctl::omp_set_num_threads(2L)
    withr::defer(RhpcBLASctl::omp_set_num_threads(RhpcBLASctl::omp_get_num_procs()))
  }

  outcomes <- execute_method_layer(
    c("a", "b"),
    run_one = function(name) name,
    workers = 2L
  )

  expect_equal(vapply(outcomes, function(o) o$value, character(1)), c("a", "b"))
  if (has_omp) {
    # The pin-and-restore happens around `mclapply()` in the parent process,
    # so the parent's own thread count is unaffected once the layer returns.
    expect_equal(RhpcBLASctl::omp_get_max_threads(), 2L)
  }
})

test_that("execute_method_layer captures output from forked workers", {
  box::use(artma / modules / method_execution[execute_method_layer])

  skip_if(!can_fork(), "forking is unavailable")

  outcomes <- testthat::expect_silent(
    execute_method_layer(
      c("a", "b"),
      run_one = function(name) {
        cli::cli_alert_info("running {name}")
        name
      },
      workers = 2L
    )
  )

  expect_true(any(grepl("running a", outcomes[[1L]]$output, fixed = TRUE)))
  expect_true(any(grepl("running b", outcomes[[2L]]$output, fixed = TRUE)))
})

test_that("execute_method_layer returns the files each method wrote", {
  box::use(
    artma / libs / infrastructure / output_files[record_output_file],
    artma / modules / method_execution[execute_method_layer]
  )

  work <- withr::local_tempdir()

  run_one <- function(name) {
    path <- file.path(work, paste0(name, ".png"))
    file.create(path)
    record_output_file(path)
    name
  }

  # Sequentially and in forks alike: a forked child records into its own copy
  # of the capture stack, so the paths only reach the parent through the
  # outcome, and the run manifest would otherwise miss every parallel method.
  for (workers in c(1L, 2L)) {
    skip_if(workers > 1L && !can_fork(), "forking is unavailable")

    outcomes <- execute_method_layer(c("a", "b"), run_one = run_one, workers = workers)

    expect_equal(basename(outcomes[[1L]]$files), "a.png")
    expect_equal(basename(outcomes[[2L]]$files), "b.png")
  }
})