# ── validate_soil_data ────────────────────────────────────────────────────────
test_that("validate_soil_data returns correct structure", {
  data(tillage_operations, package = "soiltillr")
  result <- validate_soil_data(tillage_operations, "year", "field_id", "depth_cm")
  expect_named(result, c("valid", "issues", "warnings"))
  expect_type(result$valid, "logical")
})

test_that("validate_soil_data passes clean data", {
  data(tillage_operations, package = "soiltillr")
  result <- validate_soil_data(tillage_operations, "year", "field_id", "depth_cm")
  expect_true(result$valid)
  expect_length(result$issues, 0)
})

test_that("validate_soil_data catches missing column", {
  df <- data.frame(year = 2020:2022, field = "A", depth = c(10, 15, 20))
  result <- validate_soil_data(df, "year", "field_id", "depth")
  expect_false(result$valid)
  expect_true(any(grepl("field_id", result$issues)))
})

test_that("validate_soil_data catches negative values", {
  df <- data.frame(year = 2020:2022,
                   field_id = "A",
                   depth = c(10, -5, 20))
  result <- validate_soil_data(df, "year", "field_id", "depth")
  expect_false(result$valid)
  expect_true(any(grepl("Negative", result$issues)))
})

test_that("validate_soil_data rejects empty data frame", {
  df <- data.frame(year = integer(0), field_id = character(0),
                   depth = numeric(0))
  result <- validate_soil_data(df, "year", "field_id", "depth")
  expect_false(result$valid)
})

# ── summarise_tillage ─────────────────────────────────────────────────────────
test_that("summarise_tillage returns correct structure", {
  data(tillage_operations, package = "soiltillr")
  result <- summarise_tillage(tillage_operations, "year", "field_id", "depth_cm")
  expect_s3_class(result, "data.frame")
  expect_true(all(c("year", "field_id", "n_operations",
                    "mean_depth_cm", "max_depth_cm") %in% names(result)))
})

test_that("summarise_tillage n_operations is correct", {
  df <- data.frame(
    year     = c(2020, 2020, 2021, 2021),
    field_id = c("A", "A", "A", "B"),
    depth_cm = c(10, 20, 15, 18)
  )
  result <- summarise_tillage(df, "year", "field_id", "depth_cm")
  expect_equal(result$n_operations[result$year == 2020 & result$field_id == "A"], 2)
  expect_equal(result$n_operations[result$year == 2021 & result$field_id == "A"], 1)
})

test_that("summarise_tillage mean_depth_cm is correct", {
  df <- data.frame(
    year     = c(2020, 2020, 2021, 2021),
    field_id = c("A", "A", "A", "B"),
    depth_cm = c(10, 30, 20, 25)
  )
  result <- summarise_tillage(df, "year", "field_id", "depth_cm")
  expect_equal(result$mean_depth_cm[result$year == 2020 & result$field_id == "A"], 20)
})

test_that("summarise_tillage works with op_col", {
  data(tillage_operations, package = "soiltillr")
  result <- summarise_tillage(tillage_operations, "year", "field_id",
                              "depth_cm", op_col = "operation")
  expect_true("dominant_operation" %in% names(result))
})

# ── tillage_depth_trend ───────────────────────────────────────────────────────
test_that("tillage_depth_trend returns trend column", {
  data(tillage_operations, package = "soiltillr")
  result <- tillage_depth_trend(tillage_operations, "year", "field_id", "depth_cm")
  expect_true("trend" %in% names(result))
  expect_true("baseline" %in% result$trend)
})

test_that("tillage_depth_trend first year is baseline", {
  data(tillage_operations, package = "soiltillr")
  result <- tillage_depth_trend(tillage_operations, "year", "field_id", "depth_cm")
  first_years <- result[result$trend == "baseline", ]
  expect_true(nrow(first_years) > 0)
  expect_true(all(is.na(first_years$depth_change_cm)))
})

test_that("tillage_depth_trend detects decreasing trend", {
  df <- data.frame(
    year     = rep(2020:2022, each = 1),
    field_id = rep("A", 3),
    depth_cm = c(30, 20, 10)
  )
  result <- tillage_depth_trend(df, "year", "field_id", "depth_cm")
  expect_true(any(result$trend == "decreasing"))
})

# ── detect_compaction ─────────────────────────────────────────────────────────
test_that("detect_compaction returns risk column", {
  data(tillage_operations, package = "soiltillr")
  result <- detect_compaction(tillage_operations, "year", "field_id", "depth_cm")
  expect_true("compaction_risk" %in% names(result))
  expect_true(all(result$compaction_risk %in% c("high", "moderate", "low")))
})

test_that("detect_compaction high risk for deep tillage", {
  df <- data.frame(
    year     = c(2020, 2021),
    field_id = c("A", "B"),
    depth_cm = c(32, 28)
  )
  result <- detect_compaction(df, "year", "field_id", "depth_cm",
                              compaction_threshold_cm = 20)
  expect_equal(result$compaction_risk[result$field_id == "A"], "high")
})

test_that("detect_compaction low risk for shallow tillage", {
  df <- data.frame(
    year     = c(2020, 2021),
    field_id = c("A", "B"),
    depth_cm = c(5, 8)
  )
  result <- detect_compaction(df, "year", "field_id", "depth_cm",
                              compaction_threshold_cm = 20)
  expect_equal(result$compaction_risk[result$field_id == "A"], "low")
})