buildLocationString builds the location line

buildLogOutput generates the log lines from current buffer.

buildMainWeatherLine constructs the rich first line

buildOptionLookups creates lookup maps for short-to-long names and option details.

buildURL replaces placeholders in the base URL with actual values.

checkURLForPNG returns true if the request is for a .png image but not for files in the /files/ directory.

colorForTemp returns a temperature-based color (cold blue → hot red). You can tweak the gradient here.

Helper: convert current_condition

Helper: convert hourly

convertCurrentConditionToCond converts domain.CurrentCondition to v1.cond

convertSequence converts a single ANSI sequence if it contains truecolor.

dawnTime returns civil dawn time in local HH:MM format (or "??:??" on error/failure)

────────────────────────────────────────────────────────────────────────────── Helpers (usually kept private in the same file) ───────────────────────

determineNumDays extracts forecast depth logic

diffLines returns a human-readable diff of two multi-line strings

drawAstronomical — exact port of the original Python draw_astronomical function

drawDate - respects NoCaption / NoCity indirectly through frame

drawRainSpark — now matches Python v2 label position (TOP of the sparkline)

drawWeatherEmoji renders hourly weather emojis by reusing RenderConditionEmoji from the oneline package (via a minimal dummy context).

drawWind renders the two-line wind block (exactly like Python)

duskTime returns civil dusk time in local HH:MM format (or "??:??" on error/failure)

execute runs the external program with the selected data in env vars.

extractCurrent extracts from CurrentCondition

extractQueryFromLine extracts the query from a log line and validates its format.

extractWeatherDay extracts from WeatherDay (daily + Hourly[0])

fetchAndCache performs the actual upstream request and stores the result.

fixGraphemes replaces complex graphemes with "!" and returns them separately

formatDate returns localized and optionally reversed date string for the header.

getMapKeys returns a sorted slice of keys from a map for error messages.

getUplink forwards the incoming request to one of the backend uplink servers and returns a cacheable response. It enriches the request with location

GetWeather fetches weather data while respecting the concurrency limit. It reuses HTTP connections thanks to the shared http.Client.

h2m returns minutes since midnight for a cond (used in comparison)

handleFlagOption processes flag options (e.g., "0pq" or "m") without values.

handleValueOption processes options with values (e.g., "lang=fr").

ipFromAddr extracts the IP address from an "IP:PORT" string. Returns the original string if no colon is found.

isBrowserClient determines if the User-Agent indicates a web browser. All real browsers include "Mozilla/" in their User-Agent string for historical N

loadAll preloads every language found in share/translations/

loadCertificates loads all certificates and returns a map + default cert

loadLanguage loads a single language (used during initialization)

loadTestData loads the new structured testcases.json

=================================================================== Helpers ===================================================================

openErrorFile creates and opens the error file for writing.

openLogFile opens the log file for reading.

parseColor converts a hex string (RRGGBB) or named color to color.Color

parseConditions parses the classic wttr.in conditions.txt format

preloadFontFiles extracts fonts from embed.FS to temp files once at startup

printDay renders a single forecast day in the classic v1 box style.

processLogLine processes a single log line and writes errors to the error file.

processLogLines reads and processes each line of the log file.

randInt returns a random integer in the range [min, max). Note: rand.Seed should be called once at program startup for better randomness.

renderNowWithOffset returns current local time with timezone offset

renderSections with proper terminal display width

screenToBuffer returns the screen content as [][]te.Cell

selectBestHourlySlots picks the best matching hourly entry for each target time slot.

selectFormatter chooses the appropriate formatter based on the output format option.

selectRenderer chooses the appropriate renderer based on the format option.

Helper to keep the main handler clean

serveHTTPS starts HTTPS server with support for multiple certificates via SNI

slotTimes returns the preferred times of day (in minutes since midnight) for the 4 slots.

solarNoonTime — approximate as midpoint between sunrise & sunset