test_that("defineAnalysisWindows returns correct structure with defaults", {

  windows <- defineAnalysisWindows()

  expect_true(is.list(windows))
  expect_length(windows, 8L)

  # Each element should be an analysisWindows object

  for (w in windows) {
    expect_s3_class(w, "analysisWindows")
    expect_true(all(c("startDay", "endDay", "windowName") %in% names(w)))
    expect_true(is.integer(w$startDay))
    expect_true(is.integer(w$endDay))
    expect_true(is.character(w$windowName))
  }
})

test_that("defineAnalysisWindows uses custom values", {
  windows <- defineAnalysisWindows(
    startDays = c(-30, 0),
    endDays   = c(-1, 30)
  )

  expect_length(windows, 2L)
  expect_equal(windows[[1]]$startDay, -30L)
  expect_equal(windows[[1]]$endDay, -1L)
  expect_equal(windows[[2]]$startDay, 0L)
  expect_equal(windows[[2]]$endDay, 30L)
})

test_that("defineAnalysisWindows generates automatic window names", {
  windows <- defineAnalysisWindows(
    startDays = c(-365, 1),
    endDays   = c(-1, 365)
  )

  expect_equal(windows[[1]]$windowName, "-365 to -1")
  expect_equal(windows[[2]]$windowName, "1 to 365")
})

test_that("defineAnalysisWindows accepts custom window names", {
  windows <- defineAnalysisWindows(
    startDays   = c(-30, 0),
    endDays     = c(-1, 30),
    windowNames = c("Pre-index", "Post-index")
  )

  expect_equal(windows[[1]]$windowName, "Pre-index")
  expect_equal(windows[[2]]$windowName, "Post-index")
})

test_that("defineAnalysisWindows errors on length mismatch between startDays and endDays", {
  expect_error(
    defineAnalysisWindows(startDays = c(-30, 0), endDays = c(-1)),
    "startDays and endDays must have the same length"
  )
})

test_that("defineAnalysisWindows errors on non-numeric input", {
  expect_error(
    defineAnalysisWindows(startDays = c("a", "b"), endDays = c("c", "d")),
    "startDays and endDays must be numeric"
  )

  expect_error(
    defineAnalysisWindows(startDays = c(-30, 0), endDays = c("x", "y")),
    "startDays and endDays must be numeric"
  )
})

test_that("defineAnalysisWindows errors when startDay > endDay", {
  expect_error(
    defineAnalysisWindows(startDays = c(10), endDays = c(5)),
    "Each startDay must be <= its corresponding endDay"
  )
})

test_that("defineAnalysisWindows errors on wrong windowNames length", {
  expect_error(
    defineAnalysisWindows(
      startDays = c(-30, 0), endDays = c(-1, 30),
      windowNames = c("only_one")
    ),
    "windowNames must be a character vector of the same length"
  )
})

test_that("defineAnalysisWindows errors on non-character windowNames", {
  expect_error(
    defineAnalysisWindows(
      startDays = c(-30, 0), endDays = c(-1, 30),
      windowNames = c(1, 2)
    ),
    "windowNames must be a character vector of the same length"
  )
})

test_that("defineAnalysisWindows errors on empty string windowNames", {
  expect_error(
    defineAnalysisWindows(
      startDays = c(-30, 0), endDays = c(-1, 30),
      windowNames = c("valid", "")
    ),
    "windowNames must contain non-empty strings"
  )

  expect_error(
    defineAnalysisWindows(
      startDays = c(-30, 0), endDays = c(-1, 30),
      windowNames = c("valid", "  ")
    ),
    "windowNames must contain non-empty strings"
  )
})

test_that("defineAnalysisWindows errors on NA windowNames", {
  expect_error(
    defineAnalysisWindows(
      startDays = c(-30, 0), endDays = c(-1, 30),
      windowNames = c("valid", NA_character_)
    ),
    "windowNames must contain non-empty strings"
  )
})

test_that("defineAnalysisWindows handles single window", {
  windows <- defineAnalysisWindows(startDays = 0, endDays = 0)
  expect_length(windows, 1L)
  expect_equal(windows[[1]]$startDay, 0L)
  expect_equal(windows[[1]]$endDay, 0L)
  expect_equal(windows[[1]]$windowName, "0 to 0")
})

test_that("defineAnalysisWindows coerces to integer", {
  windows <- defineAnalysisWindows(startDays = -30.0, endDays = -1.0)
  expect_true(is.integer(windows[[1]]$startDay))
  expect_true(is.integer(windows[[1]]$endDay))
})