test_that("gui_tga_curve validates columns and coerces to numeric", {
  df <- data.frame(T = c("25", "50", "100"), W = c("100.0", "99.8", "98.1"))
  out <- gui_tga_curve(df, "T", "W")
  expect_equal(names(out), c("temperature_C", "weight_pct"))
  expect_equal(out$temperature_C, c(25, 50, 100))
  expect_error(gui_tga_curve(df, "nope", "W"), "not found")
})

test_that("gui_tga_stages feeds into biocharkit::proximate_analysis correctly", {
  T <- seq(25, 800, by = 5)
  W <- ifelse(T <= 110, 100 - (5 / 110) * T,
       ifelse(T <= 650, 95 - (40 / (650 - 110)) * (T - 110), 55))
  df <- data.frame(temp = T, wt = W)
  out <- gui_tga_stages(df, "temp", "wt")
  expect_equal(out$moisture_pct, 5, tolerance = 0.5)
  expect_equal(out$VM_pct, 40, tolerance = 0.5)
  expect_equal(out$ash_pct, 55, tolerance = 0.5)
})

test_that("gui_tga_stages respects custom moisture_end/vm_end breakpoints", {
  T <- seq(25, 800, by = 5)
  W <- ifelse(T <= 150, 100 - (8 / 150) * T,
       ifelse(T <= 600, 92 - (37 / (600 - 150)) * (T - 150), 55))
  df <- data.frame(temp = T, wt = W)
  out <- gui_tga_stages(df, "temp", "wt", moisture_end = 150, vm_end = 600)
  expect_equal(out$moisture_end_C, 150)
  expect_equal(out$vm_end_C, 600)
  expect_equal(out$moisture_pct, 8, tolerance = 0.5)
})

test_that("gui_tga_stages_batch processes multiple samples and skips failures with a warning", {
  mk <- function(id, vm_center) {
    Tt <- seq(25, 800, by = 10)
    Ww <- 100 - 5 * (Tt > 110) - 40 / (1 + exp(-(Tt - vm_center) / 20))
    data.frame(id = id, temp = Tt, wt = Ww)
  }
  good <- rbind(mk("A", 300), mk("B", 380))
  bad <- data.frame(id = "C", temp = c(25, 50), wt = c(100, 99))
  df <- rbind(good, bad)

  expect_warning(out <- gui_tga_stages_batch(df, "id", "temp", "wt"), "could not be processed")
  expect_equal(sort(unique(out$id)), c("A", "B"))
})

test_that("gui_tga_stages_batch errors on missing columns", {
  df <- data.frame(id = "A", x = 1, y = 2)
  expect_error(gui_tga_stages_batch(df, "id", "temp", "wt"), "not found")
})

test_that("gui_tga_kissinger returns a display-ready one-row params table", {
  df <- data.frame(beta = c(5, 10, 15, 20), Tpeak = c(320, 335, 344, 351))
  res <- gui_tga_kissinger(df, "beta", "Tpeak")
  expect_equal(nrow(res$params), 1)
  expect_true(all(c("Ea_kJmol", "A_min1", "R2") %in% names(res$params)))
  expect_true(res$params$R2 > 0.99)
  expect_false(is.null(res$fit$model))
})

test_that("gui_tga_kissinger errors on missing columns", {
  df <- data.frame(x = 1:3, y = 1:3)
  expect_error(gui_tga_kissinger(df, "beta", "Tpeak"), "not found")
})