# ==============================================================================
# tests/testthat/test-roost_plot.R
# ==============================================================================

make_roost_like <- function() {
  d <- data.frame(
    month = as.Date(c("2024-01-01", "2024-02-01", "2024-03-01")),
    n     = c(10L, 14L, 9L)
  )
  attr(d, "roost_meta") <- list(time_unit = "month")
  d
}

make_roost_like_stacked <- function() {
  d <- data.frame(
    month     = rep(as.Date(c("2024-01-01", "2024-02-01")), each = 2),
    hosp_label = rep(c("Community", "Hospitalised"), 2),
    n          = c(8L, 2L, 11L, 3L)
  )
  attr(d, "roost_meta") <- list(time_unit = "month")
  d
}

make_roost_like_corrected <- function() {
  d <- make_roost_like()
  d$corrected_count       <- d$n * 2
  d$corrected_count_lower <- d$n * 1.5
  d$corrected_count_upper <- d$n * 2.5
  d
}

test_that("roost_plot() auto-detects x from roost_meta and y from 'n'", {
  p <- roost_plot(make_roost_like())
  expect_s3_class(p, "ggplot")
  built <- ggplot2::layer_data(p, 1)
  expect_equal(sort(built$y), sort(c(10, 14, 9)))
})

test_that("roost_plot() errors when x cannot be auto-detected and isn't supplied", {
  d <- data.frame(month = as.Date("2024-01-01"), n = 5L)
  expect_error(roost_plot(d), "auto-detected")
})

test_that("roost_plot() requires y when several n_* columns exist and none is 'n'", {
  d <- data.frame(month = as.Date("2024-01-01"), n_cases = 5L, n_deaths = 1L)
  attr(d, "roost_meta") <- list(time_unit = "month")
  expect_error(roost_plot(d), "n_cases, n_deaths")
})

test_that("roost_plot() resolves a single n_* candidate automatically", {
  d <- data.frame(month = as.Date("2024-01-01"), n_cases = 5L)
  attr(d, "roost_meta") <- list(time_unit = "month")
  p <- roost_plot(d)
  expect_s3_class(p, "ggplot")
})

test_that("roost_plot() stacks bars by stack_by", {
  p <- roost_plot(make_roost_like_stacked(), stack_by = "hosp_label", type = "bar")
  built <- ggplot2::layer_data(p, 1)
  expect_equal(nrow(built), 4)  # 2 months x 2 strata
})

test_that("roost_plot() auto-detects and draws a corrected_count overlay", {
  p <- roost_plot(make_roost_like_corrected())
  # bars (layer 1) + ribbon (layer 2) + corrected line (layer 3)
  expect_gte(length(p$layers), 3)
  line_layer <- ggplot2::layer_data(p, length(p$layers))
  expect_equal(sort(line_layer$y), sort(c(20, 28, 18)))
})

test_that("roost_plot() show_corrected = FALSE suppresses the overlay even when present", {
  p <- roost_plot(make_roost_like_corrected(), show_corrected = FALSE)
  expect_equal(length(p$layers), 1)  # bars only
})

test_that("roost_plot() show_corrected = TRUE errors if corrected_count is absent", {
  expect_error(roost_plot(make_roost_like(), show_corrected = TRUE), "corrected_count")
})

test_that("roost_plot() corrected_smooth changes the plotted corrected values", {
  d <- data.frame(
    month = seq(as.Date("2024-01-01"), by = "month", length.out = 8),
    n     = c(10L, 50L, 12L, 9L, 45L, 11L, 10L, 48L)  # jagged, so smoothing has a visible effect
  )
  attr(d, "roost_meta") <- list(time_unit = "month")
  d$corrected_count <- d$n * 2

  p_raw    <- roost_plot(d, corrected_smooth = FALSE)
  p_smooth <- roost_plot(d, corrected_smooth = TRUE)
  line_raw    <- ggplot2::layer_data(p_raw, length(p_raw$layers))
  line_smooth <- ggplot2::layer_data(p_smooth, length(p_smooth$layers))
  expect_false(isTRUE(all.equal(line_raw$y, line_smooth$y)))
})

test_that("roost_plot() sums the corrected overlay across stack_by groups", {
  d <- make_roost_like_stacked()
  d$corrected_count <- d$n * 2
  p <- roost_plot(d, stack_by = "hosp_label")
  line_layer <- ggplot2::layer_data(p, length(p$layers))
  # Jan: (8+2)*2 = 20 ; Feb: (11+3)*2 = 28
  expect_equal(sort(line_layer$y), sort(c(20, 28)))
})

test_that("roost_plot() rejects a non-data.frame", {
  expect_error(roost_plot(list(a = 1)), "data frame")
})

test_that("roost_plot() rejects an unknown stack_by column", {
  expect_error(roost_plot(make_roost_like(), stack_by = "not_a_col"), "not found")
})

test_that("roost_plot() interactive = TRUE without plotly errors informatively", {
  skip_if(requireNamespace("plotly", quietly = TRUE),
          "plotly is installed; this test only applies when it's absent")
  expect_error(roost_plot(make_roost_like(), interactive = TRUE), "plotly")
})