Stand alone, document, and let the config show anythingv0.1.1

prognosis no longer reads ~/.wegorc. Falling back to another program's
configuration made it useless without wego installed, and hid the fact that
it has no way to know where you are: location= is now required in its own
config, and the error says so and shows how to set it.

Custom columns. Any field the two Open-Meteo APIs expose can be displayed by
declaring it -- column.birch = air:birch_pollen -- and then naming it in
columns=. The source is explicit because forecast and air-quality are separate
services with separate fields; an air column costs one extra request, made only
when one is declared. Air values merge onto forecast hours by timestamp rather
than array index, since nothing guarantees the two endpoints start at the same
hour and merging by position would shift a column by an hour unnoticed. A value
the API withholds renders blank, not zero: for an allergen those are different
claims.

Pollen selection no longer privileges grass. A species named in pollen= is
shown even at zero, because you named it for a reason; pollen=all shows only
what is present, or the line is six zeroes. Grass had been special-cased, which
forced it on someone allergic to birch while hiding theirs.

Temperature colours are compared in Celsius whatever the display units. In
imperial, 85F -- a mild 29C -- was rendering in the red that means IMGW would
issue a heat warning.

A man page, checked by make lint and installed by make install. The Makefile
gains PREFIX/DESTDIR for packaging, a version stamped into the binary, a
release target that refuses to tag a dirty tree or a version with no changelog
entry, cross-compilation for six platforms, and a pre-push hook.

Also: humidity in the default columns, -weather for output meant for someone
else, -ascii so an SMS stays in GSM-7 rather than dropping to 70-character
UCS-2 segments, and -pollen and -version.

1 files changed, 59 insertions, 35 deletions

diff --git a/cmd/prognosis/main.go b/cmd/prognosis/main.go
index 6e29c8e..3075563 100644
--- a/cmd/prognosis/main.go
+++ b/cmd/prognosis/main.go
@@ -3,7 +3,6 @@
 package main
 
 import (
-	"bufio"
 	"errors"
 	"flag"
 	"fmt"
@@ -19,7 +18,9 @@ import (
 	"github.com/lukaszkasprzak/prognosis/internal/render"
 )
 
-const wegorc = ".wegorc"
+// version is stamped at build time: -ldflags "-X main.version=$(git describe)".
+// "dev" means someone built it straight from a working tree.
+var version = "dev"
 
 func main() { os.Exit(run()) }
 
@@ -28,12 +29,13 @@ func run() int {
 	configureResolver()
 
 	var (
-		location = flag.String("l", "", "place to query (default: config, then ~/.wegorc)")
+		location = flag.String("l", "", "place to query (default: location= in the config file)")
 		hours    = flag.Int("n", 0, "hours ahead to show")
 		days     = flag.Int("d", 0, "days ahead to show, 24h each")
 		columns  = flag.String("columns", "", "comma-separated columns to display")
 		icons    = flag.String("icons", "", "icon set: nerd, emoji or none")
 		lang     = flag.String("lang", "", "display language: en or pl")
+		pollen   = flag.String("pollen", "", "pollen species to show: a list, or all / none")
 		noGraph  = flag.Bool("no-graph", false, "table only, no chart")
 		weather  = flag.Bool("weather", false, "forecast only: no sun times, summary, pollen or chart")
 		noWarn   = flag.Bool("no-warnings", false, "omit IMGW warnings")
@@ -41,6 +43,7 @@ func run() int {
 		noColor  = flag.Bool("no-color", false, "plain output")
 		pick     = flag.Int("pick", 0, "choose the Nth place when the name is ambiguous")
 		showCfg  = flag.Bool("config", false, "print the config file path and exit")
+		showVer  = flag.Bool("version", false, "print the version and exit")
 	)
 	flag.Usage = usage
 	// Go's flag package stops at the first non-flag argument, so
@@ -59,6 +62,11 @@ func run() int {
 		rest = flag.Args()[1:]
 	}
 
+	if *showVer {
+		fmt.Printf("prognosis %s\n", version)
+		return 0
+	}
+
 	cfgPath := config.Path()
 	if *showCfg {
 		fmt.Println(cfgPath)
@@ -87,6 +95,16 @@ func run() int {
 	if *lang != "" {
 		cfg.DisplayLang = *lang
 	}
+	if *pollen != "" {
+		switch *pollen {
+		case "all":
+			cfg.Pollen, cfg.PollenExplicit = append([]string(nil), config.AllSpecies...), false
+		case "none":
+			cfg.Pollen, cfg.PollenExplicit = nil, false
+		default:
+			cfg.Pollen, cfg.PollenExplicit = splitList(*pollen), true
+		}
+	}
 	if *noGraph {
 		cfg.Graph = false
 	}
@@ -147,10 +165,9 @@ func run() int {
 		cfg.Location = place
 	}
 	if cfg.Location == "" {
-		cfg.Location = locationFromWegorc()
-	}
-	if cfg.Location == "" {
-		fmt.Fprintf(os.Stderr, "prognosis: no location set in %s and none in ~/%s\n", cfgPath, wegorc)
+		fmt.Fprintf(os.Stderr,
+			"prognosis: no location set. Put one in %s:\n\n    location=Krakow\n\n"+
+				"or pass it for one run: prognosis -l Krakow\n", cfgPath)
 		return 2
 	}
 
@@ -180,6 +197,17 @@ func run() int {
 		fmt.Fprintf(os.Stderr, "note: %d %s %d\n", len(data.Rows), cat.Word("hours_available"), cfg.Hours)
 	}
 
+	// Custom air-quality columns need a second request, made only when the
+	// config actually declares one.
+	if fields := cfg.AirFields(); len(fields) > 0 {
+		hourly, err := openmeteo.AirHourly(geo.Lat, geo.Lon, cfg.Hours, fields)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "note: air-quality data unavailable: %v\n", err)
+		} else {
+			mergeCustom(data.Rows, hourly, cfg)
+		}
+	}
+
 	view := render.View{
 		Label: geo.Label, TZ: data.TZ, Rows: data.Rows,
 		Sun: data.Sun, Daily: data.Daily,
@@ -350,33 +378,6 @@ func parseCoords(s string) (float64, float64, bool) {
 	return a, b, true
 }
 
-// locationFromWegorc reads location= from wego's config, so the two tools never
-// disagree about where you are.
-func locationFromWegorc() string {
-	home, err := os.UserHomeDir()
-	if err != nil {
-		return ""
-	}
-	f, err := os.Open(home + "/" + wegorc)
-	if err != nil {
-		return ""
-	}
-	defer f.Close()
-	sc := bufio.NewScanner(f)
-	for sc.Scan() {
-		line := strings.TrimSpace(sc.Text())
-		if line == "" || strings.HasPrefix(line, "#") {
-			continue
-		}
-		if k, v, ok := strings.Cut(line, "="); ok && strings.TrimSpace(k) == "location" {
-			if v = strings.TrimSpace(v); v != "" {
-				return v
-			}
-		}
-	}
-	return ""
-}
-
 func shouldColour(mode string) bool {
 	switch mode {
 	case "never":
@@ -424,18 +425,41 @@ func usage() {
 usage: prognosis [flags] [place]
 
 flags:
-  -l PLACE       place to query (default: config, then ~/.wegorc)
+  -l PLACE       place to query (default: location= in the config file)
   -pick N        choose the Nth place when the name matches several
   -n N           hours ahead to show
   -d N           days ahead to show, 24h each (max %d)
   -columns LIST  comma-separated columns; valid: %s
   -icons SET     nerd, emoji or none
   -lang LANG     en or pl
+  -pollen LIST   pollen species to show: a list, or all / none
   -no-graph      table only
   -weather       forecast only: no sun times, summary, pollen or chart
   -no-warnings   omit IMGW warnings
   -ascii         ASCII only, so an SMS stays in GSM-7 (160 chars, not 70)
   -no-color      plain output
   -config        print the config file path and exit
+  -version       print the version and exit
 `, openmeteo.MaxForecastDays-1, strings.Join(config.ValidColumns(), ", "))
 }
+
+// mergeCustom copies air-quality values onto the matching forecast hour.
+//
+// Custom values are stored under the column's own name, prefixed, so they can
+// never collide with an API field name already in the row.
+func mergeCustom(rows []openmeteo.Row, hourly map[string]map[string]float64, cfg config.Config) {
+	for i, r := range rows {
+		byField, ok := hourly[r.When.Format("2006-01-02T15:04")]
+		if !ok {
+			continue
+		}
+		for name, cc := range cfg.Custom {
+			if cc.Source != "air" {
+				continue
+			}
+			if v, ok := byField[cc.Field]; ok {
+				rows[i].Vals[render.CustomKey(name)] = v
+			}
+		}
+	}
+}