# Tests for utility functions

test_that("simulate_invasion generates correct structure", {
  dat <- simulate_invasion(n_years = 25, seed = 123)

  expect_true(is.data.frame(dat))
  expect_true("year" %in% names(dat))
  expect_true("count" %in% names(dat))
  expect_true("true_phase" %in% names(dat))
  expect_equal(nrow(dat), 25)
})

test_that("simulate_invasion respects parameters", {
  dat <- simulate_invasion(
    n_years = 40,
    start_year = 1980,
    lag_duration = 15,
    seed = 123
  )

  expect_equal(min(dat$year), 1980)
  expect_equal(max(dat$year), 2019)
  expect_equal(attr(dat, "true_breakpoint"), 1995)
})

test_that("simulate_invasion generates effort when requested", {
  dat <- simulate_invasion(effort = TRUE, seed = 123)

  expect_true("effort" %in% names(dat))
  expect_true(all(dat$effort > 0))
})

test_that("invasion_summary computes correct statistics", {
  dat <- simulate_invasion(n_years = 20, seed = 123)
  stats <- invasion_summary(dat$year, dat$count)

  expect_s3_class(stats, "invasion_summary")
  expect_equal(stats$time_span$duration, 20)
  expect_equal(stats$counts$total, sum(dat$count))
  expect_true(!is.null(stats$assessment))
})

test_that("validate_invasion_data catches issues", {
  # Good data should pass
  dat <- simulate_invasion(seed = 123)
  expect_true(validate_invasion_data(dat$year, dat$count))

  # Different lengths should fail
  expect_false(suppressWarnings(
    validate_invasion_data(1:10, 1:5)
  ))
})

test_that("aggregate_by_year works correctly", {
  raw <- data.frame(
    year = c(2000, 2000, 2000, 2001, 2001, 2002),
    species = "test"
  )

  agg <- aggregate_by_year(raw, "year")

  expect_equal(nrow(agg), 3)
  expect_equal(agg$count[agg$year == 2000], 3)
  expect_equal(agg$count[agg$year == 2001], 2)
  expect_equal(agg$count[agg$year == 2002], 1)
})