library(testthat)
library(rainerosr)

test_that("validate_rainfall_data detects missing columns", {
  data <- data.frame(time = 1:5, wrong_col = 1:5)
  
  result <- validate_rainfall_data(data, "time", "depth")
  
  expect_false(result$valid)
  expect_true(any(grepl("Depth column", result$issues)))
})

test_that("validate_rainfall_data detects negative rainfall", {
  data <- data.frame(
    time = as.POSIXct(c("2024-01-01 10:00", "2024-01-01 10:15")),
    depth = c(5, -2)
  )
  
  result <- validate_rainfall_data(data, "time", "depth")
  
  expect_false(result$valid)
  expect_true(any(grepl("Negative rainfall", result$issues)))
})

test_that("validate_rainfall_data detects non-monotonic time", {
  data <- data.frame(
    time = as.POSIXct(c("2024-01-01 10:00", "2024-01-01 09:00")),
    depth = c(5, 3)
  )
  
  result <- validate_rainfall_data(data, "time", "depth")
  
  expect_false(result$valid)
  expect_true(any(grepl("monotonically", result$issues)))
})

test_that("validate_rainfall_data passes valid data", {
  data <- data.frame(
    time = as.POSIXct(c("2024-01-01 10:00", "2024-01-01 10:15", "2024-01-01 10:30")),
    depth = c(5.2, 3.1, 2.8)
  )
  
  result <- validate_rainfall_data(data, "time", "depth")
  
  expect_true(result$valid)
  expect_length(result$issues, 0)
})

test_that("validate_rainfall_data warns on very small rainfall", {
  data <- data.frame(
    time = as.POSIXct(c("2024-01-01 10:00", "2024-01-01 10:15")),
    depth = c(0.3, 0.2)
  )
  
  result <- validate_rainfall_data(data, "time", "depth")
  
  expect_true(any(grepl("less than 1 mm", result$warnings)))
})