-- Checks for lib/weather.lua.
-- Run from the repo root:  lua test/test_weather.lua
-- The domain tables are what silently misreport when a boundary is off by one,
-- so every range boundary gets an assertion. The card itself is verified by
-- screenshot.

package.path = './?.lua;' .. package.path
local weather = require 'lib.weather'

-- === Condition id to icon =================================================
-- OWM ids group by hundreds, but the boundaries are not round numbers: the
-- ranges come from the polybar script that ran against this API for years.
-- Each assertion pairs the last id in a range with the first id of the next,
-- which is where an off-by-one would hide.
-- Sunrise 1500, sunset 1900, so DAY must sit INSIDE that window and NIGHT
-- outside it. Naming them without checking them against the window is how the
-- first draft of this test made every timestamp evaluate as night.
local DAY, NIGHT = 1700, 2000

local function icon(id, now)
  return weather.icon(id, now, 1500, 1900)   -- sunrise 1500, sunset 1900
end

-- Thunderstorm: everything up to 232.
assert(icon(200, DAY) == weather.ICON.thunder_day, 'id 200 day')
assert(icon(232, DAY) == weather.ICON.thunder_day, 'id 232 is still thunder')
assert(icon(232, NIGHT) == weather.ICON.thunder_night, 'id 232 night')

-- Light drizzle: 233..311.
assert(icon(233, DAY) == weather.ICON.drizzle_day, 'id 233 leaves thunder')
assert(icon(311, DAY) == weather.ICON.drizzle_day, 'id 311 is still light drizzle')

-- Heavy drizzle: 312..321.
assert(icon(312, DAY) == weather.ICON.drizzle_heavy_day, 'id 312 is heavy drizzle')
assert(icon(321, DAY) == weather.ICON.drizzle_heavy_day, 'id 321 is still heavy drizzle')

-- Rain: 322..531.
assert(icon(322, DAY) == weather.ICON.rain_day, 'id 322 is rain')
assert(icon(531, DAY) == weather.ICON.rain_day, 'id 531 is still rain')

-- Snow: 532..622. One icon, no day/night variant.
assert(icon(600, DAY) == weather.ICON.snow, 'id 600 is snow')
assert(icon(622, NIGHT) == weather.ICON.snow, 'snow is the same at night')

-- Fog: 623..771.
assert(icon(741, DAY) == weather.ICON.fog, 'id 741 is fog')
assert(icon(771, DAY) == weather.ICON.fog, 'id 771 is still fog')

-- Tornado is a single id, not a range.
assert(icon(781, DAY) == weather.ICON.tornado, 'id 781 is tornado')

-- Clear and few clouds each have a day and a night face.
assert(icon(800, DAY) == weather.ICON.clear_day, 'id 800 day is the sun')
assert(icon(800, NIGHT) == weather.ICON.clear_night, 'id 800 night is the moon')
assert(icon(801, DAY) == weather.ICON.few_day, 'id 801 day')
assert(icon(801, NIGHT) == weather.ICON.few_night, 'id 801 night')

-- Overcast: 802..804, no night variant.
assert(icon(804, DAY) == weather.ICON.overcast, 'id 804 is overcast')

-- Anything outside the known ids must be visibly wrong, not silently sunny.
assert(icon(999, DAY) == weather.ICON.unknown, 'unknown id gets the error glyph')
assert(weather.icon(nil, DAY, 1500, 1900) == weather.ICON.unknown, 'nil id')

-- Nothing may raise. A missing timestamp with a known sun, or a known
-- timestamp with no sun, both have to return a glyph rather than an error,
-- because an error here is a blank dashboard with no message.
assert(weather.icon(800, nil, 1500, 1900) == weather.ICON.clear_day,
  'a nil now must not raise, and falls back to the day face')
assert(weather.icon(800, DAY, nil, nil) == weather.ICON.clear_day,
  'no sun times must not raise')

-- The codepoint VALUES are deliberately not asserted. A test comparing
-- M.ICON.snow against a literal would only prove the same escape was typed
-- twice; whether E31A actually draws a snow cloud in the target font is not
-- something an assertion can see. That check is the glyph sheet rendered in
-- the plan's Step 5, and it is how a wrong-but-present codepoint was caught
-- before this file existed.

-- === Wind =================================================================
-- OWM metric gives m/s; the card shows km/h. The conversion is where a wrong
-- factor would look plausible but read 3.6x off.
assert(weather.kmh(10) == 36, '10 m/s is 36 km/h')
assert(weather.kmh(0) == 0, 'calm')
assert(weather.kmh(nil) == nil, 'missing wind speed stays missing')

-- Beaufort thresholds, in km/h, from the polybar script. Each assertion sits
-- on a boundary and just past it, which is where an inclusive/exclusive
-- mistake hides.
assert(weather.beaufort(0) == 0, 'calm is force 0')
assert(weather.beaufort(1) == 0, '1 km/h is still force 0')
assert(weather.beaufort(2) == 1, 'just over 1 is force 1')
assert(weather.beaufort(5) == 1, '5 is still force 1')
assert(weather.beaufort(6) == 2, 'just over 5 is force 2')
assert(weather.beaufort(11) == 2, '11 is still force 2')
assert(weather.beaufort(12) == 3, 'just over 11 is force 3')
assert(weather.beaufort(19) == 3, '19 is still force 3')
assert(weather.beaufort(28) == 4, '28 is force 4')
assert(weather.beaufort(38) == 5, '38 is force 5')
assert(weather.beaufort(49) == 6, '49 is force 6')
assert(weather.beaufort(61) == 7, '61 is force 7')
assert(weather.beaufort(74) == 8, '74 is force 8')
assert(weather.beaufort(88) == 9, '88 is force 9')
assert(weather.beaufort(102) == 10, '102 is force 10')
assert(weather.beaufort(117) == 11, '117 is force 11')
assert(weather.beaufort(118) == 12, 'over 117 is hurricane force')

-- Compass: eight points, each spanning 45 degrees, offset by half a step so
-- north straddles 0 rather than starting at it. The wraparound is the case
-- that a naive floor(deg/45) gets wrong.
assert(weather.compass(0) == 'N', '0 is north')
assert(weather.compass(360) == 'N', '360 wraps to north')
assert(weather.compass(11) == 'N', 'just under the NE boundary')
assert(weather.compass(349) == 'N', 'just over the NW boundary wraps to north')
assert(weather.compass(45) == 'NE', '45 is northeast')
assert(weather.compass(90) == 'E', '90 is east')
assert(weather.compass(135) == 'SE', '135 is southeast')
assert(weather.compass(180) == 'S', '180 is south')
assert(weather.compass(225) == 'SW', '225 is southwest')
assert(weather.compass(270) == 'W', '270 is west')
assert(weather.compass(315) == 'NW', '315 is northwest')
assert(weather.compass(nil) == nil, 'missing direction stays missing')

-- The arrow points where the wind is going, and OWM reports where it comes
-- from, so a north wind draws a downward arrow.
assert(weather.arrow(0) == '\u{2193}', 'a north wind blows southward')
assert(weather.arrow(180) == '\u{2191}', 'a south wind blows northward')
assert(weather.arrow(nil) == '', 'no direction draws nothing')

-- === Sun position =========================================================
-- t is the fraction of daylight elapsed, and the widget uses it to place the
-- dot along the arc. Sunrise 1000, sunset 2000, so midday is 1500.
assert(weather.sun_t(1000, 1000, 2000) == 0, 'at sunrise t is 0')
assert(weather.sun_t(1500, 1000, 2000) == 0.5, 'at midday t is half')
assert(weather.sun_t(2000, 1000, 2000) == 1, 'at sunset t is 1')

-- OWM reports today's sunrise and sunset, so between midnight and sunrise the
-- numerator is negative. The clamp is the whole handling; without it the dot
-- would be drawn off the left end of the arc.
assert(weather.sun_t(500, 1000, 2000) == 0, 'before dawn clamps to 0')
assert(weather.sun_t(9999, 1000, 2000) == 1, 'after dusk clamps to 1')

-- Degenerate input must not divide by zero.
assert(weather.sun_t(1500, 2000, 2000) == 0, 'zero-length day gives 0, not nan')
assert(weather.sun_t(nil, 1000, 2000) == nil, 'missing now gives nil')
assert(weather.sun_t(1500, nil, 2000) == nil, 'missing sunrise gives nil')

-- is_day drives both the icon face and the dot's colour: a dot parked at the
-- end of the arc must not read as a sun that is still up.
assert(weather.is_day(1500, 1000, 2000) == true, 'midday is day')
assert(weather.is_day(1000, 1000, 2000) == true, 'sunrise counts as day')
assert(weather.is_day(2000, 1000, 2000) == true, 'sunset counts as day')
assert(weather.is_day(500, 1000, 2000) == false, 'before dawn is night')
assert(weather.is_day(2500, 1000, 2000) == false, 'after dusk is night')

-- === Parsing the cache ====================================================
-- The parser reads scalars by key with Lua patterns rather than pulling in a
-- JSON library: the response is flat and known, and six numbers do not justify
-- a dependency. Caching the whole response still costs nothing, since a field
-- added later is already on disk.
local function read(path)
  local f = assert(io.open(path, 'r'))
  local s = f:read('*a')
  f:close()
  return s
end

local w = weather.parse(read('test/fixtures/weather.json'))
assert(w, 'the fixture must parse')
assert(w.id == 501, 'condition id, got ' .. tostring(w.id))
assert(w.description == 'moderate rain', 'description, got ' .. tostring(w.description))
assert(w.temp == 18.34, 'temp, got ' .. tostring(w.temp))
assert(w.feels_like == 18.11, 'feels like, got ' .. tostring(w.feels_like))
assert(w.humidity == 72, 'humidity, got ' .. tostring(w.humidity))
assert(w.wind_speed == 4.12, 'wind m/s, got ' .. tostring(w.wind_speed))
assert(w.wind_deg == 230, 'wind direction, got ' .. tostring(w.wind_deg))
assert(w.sunrise == 1789600000, 'sunrise, got ' .. tostring(w.sunrise))
assert(w.sunset == 1789646000, 'sunset, got ' .. tostring(w.sunset))
assert(w.city == 'Example City', 'city, got ' .. tostring(w.city))
assert(w.dt == 1789625000, 'observation time, got ' .. tostring(w.dt))

-- temp comes before feels_like in the response and both live under "main",
-- so a lazy pattern would read one for the other. They differ in the fixture
-- precisely so this is checkable.
assert(w.temp ~= w.feels_like, 'temp and feels_like must not collapse')

-- Failure modes all return nil rather than raising: a Lua error here is a
-- blank dashboard, not a message.
assert(weather.parse(read('test/fixtures/weather_truncated.json')) == nil,
  'a truncated response must give nil')
assert(weather.parse('') == nil, 'empty input gives nil')
assert(weather.parse('not json at all') == nil, 'garbage gives nil')
assert(weather.parse(nil) == nil, 'nil input gives nil')

-- An error body carries cod 401 and no weather. It must not parse as data.
assert(weather.parse('{"cod":401,"message":"Invalid API key."}') == nil,
  'an API error body must give nil')

-- Negative temperatures are ordinary here for half the year, and a number in
-- exponent form must not be truncated at the 'e': reading 1.8e1 as 1.8 would
-- draw 2 degrees instead of 18, wrong in a way that still looks like weather.
local cold = weather.parse(
  '{"weather":[{"id":600,"description":"snow"}],"main":{"temp":-12.5},' ..
  '"sys":{"sunrise":100,"sunset":200},"name":"X","dt":150}')
assert(cold and cold.temp == -12.5, 'a negative temp, got ' .. tostring(cold and cold.temp))
local exp = weather.parse(
  '{"weather":[{"id":800}],"main":{"temp":1.8e1},' ..
  '"sys":{"sunrise":100,"sunset":200}}')
assert(exp and exp.temp == 18, 'exponent form, got ' .. tostring(exp and exp.temp))

-- === Staleness ============================================================
-- 45 minutes is three missed fetches at the 15-minute interval, so one
-- transient failure does not flag the card.
assert(weather.is_stale(1000, 1000) == false, 'a fresh reading is not stale')
assert(weather.is_stale(1000, 1000 + 45 * 60) == false, 'exactly 45 min is the boundary')
assert(weather.is_stale(1000, 1000 + 45 * 60 + 1) == true, 'past 45 min is stale')
assert(weather.is_stale(nil, 1000) == true, 'no observation time counts as stale')

-- The age string is what the card prints beside the city, so it must be short.
assert(weather.age_str(1000, 1000 + 90) == '1m', 'ninety seconds reads as 1m')
assert(weather.age_str(1000, 1000 + 3600) == '1h', 'an hour reads as 1h')
assert(weather.age_str(1000, 1000 + 7200) == '2h', 'two hours')
assert(weather.age_str(1000, 1000 + 86400 * 2) == '2d', 'days, once it gets that bad')

-- Neither takes `now` on faith: a nil there used to raise, and a raise is a
-- blank dashboard rather than a message.
assert(weather.is_stale(1000, nil) == true, 'a nil now must not raise')
assert(weather.age_str(1000, nil) == '?', 'a nil now must not raise')

-- A dt in the future means a clock skew. "stale -17m" reads as a broken
-- widget, so the age floors at zero and the reading counts as fresh.
assert(weather.age_str(2000, 1000) == '0m', 'a future dt reads as 0m, got ' ..
  tostring(weather.age_str(2000, 1000)))
assert(weather.is_stale(2000, 1000) == false, 'a future dt is not stale')

print('test_weather: all assertions passed')