Sample env carries a version marker; install appends settings missing since the writing version

internal/config/sample.go

@@ -2,6 +2,7 @@ package config
 
 import (
 	"fmt"
+	"strconv"
 	"strings"
 )
 
@@ -14,12 +15,14 @@ type sampleEntry struct {
 	active  bool // rendered uncommented
 }
 
-// SampleEnv renders a sample .env file covering every setting, each with a
-// comment line. Everything is commented out — so all defaults apply —
-// except LOG_FILE when logFile is non-empty: a Windows service has no
-// console, so the installer pre-wires file logging there.
-func SampleEnv(logFile string) string {
-	entries := []sampleEntry{
+// versionMarker prefixes the first line of an installer-written env file so
+// later installs can tell which version wrote it.
+const versionMarker = "# gpu-turnstile version: "
+
+// sampleEntries lists every setting in sample order. logFile activates the
+// LOG_FILE line (Windows install); empty keeps it commented like the rest.
+func sampleEntries(logFile string) []sampleEntry {
+	return []sampleEntry{
 		{"LISTEN_OLLAMA", ":11434", "Ollama-facing listener address", false},
 		{"LISTEN_COMFY", ":8188", "ComfyUI-facing listener address", false},
 		{"OLLAMA_URL", "http://127.0.0.1:11434", "Ollama upstream URL; setting it enables the Ollama consumer (default: empty = disabled)", false},
@@ -48,18 +51,111 @@ func SampleEnv(logFile string) string {
 		{"UPDATE_REPO", "https://git.rambossek.at/PUBLIC/gpu-turnstile", "Repository to check for releases", false},
 		{"UPDATE_ASSET", "gpu-turnstile.exe", "Release asset to download", false},
 	}
+}
+
+// SampleEnv renders a sample .env file covering every setting, each with a
+// comment line. Everything is commented out — so all defaults apply —
+// except LOG_FILE when logFile is non-empty: a Windows service has no
+// console, so the installer pre-wires file logging there. The first line
+// carries the writing version so later installs can upgrade the file.
+func SampleEnv(version, logFile string) string {
 	var b strings.Builder
-	b.WriteString("# gpu-turnstile configuration\n")
+	b.WriteString(versionMarker + version + "\n")
 	b.WriteString("# KEY=VALUE lines; \"#\" starts a comment. Every setting below is at its\n")
 	b.WriteString("# default and commented out — remove the \"#\" to change it.\n")
 	b.WriteString("# At least one of OLLAMA_URL / COMFY_URL must be set for the proxy to start.\n\n")
-	for _, e := range entries {
-		fmt.Fprintf(&b, "# %s\n", e.comment)
-		if e.active {
-			fmt.Fprintf(&b, "%s=%s\n\n", e.name, e.value)
-		} else {
-			fmt.Fprintf(&b, "#%s=%s\n\n", e.name, e.value)
-		}
+	for _, e := range sampleEntries(logFile) {
+		writeEntry(&b, e)
 	}
 	return b.String()
 }
+
+func writeEntry(b *strings.Builder, e sampleEntry) {
+	fmt.Fprintf(b, "# %s\n", e.comment)
+	if e.active {
+		fmt.Fprintf(b, "%s=%s\n\n", e.name, e.value)
+	} else {
+		fmt.Fprintf(b, "#%s=%s\n\n", e.name, e.value)
+	}
+}
+
+// SyncSample upgrades an installer-written env file: when its version
+// marker says it was written by an older gpu-turnstile, every setting the
+// file does not mention — commented or not — is appended at the end, and
+// the marker is updated to version. Files without the marker (hand-written
+// configs) and up-to-date files are returned unchanged; changed reports
+// whether the returned content differs. A "dev" version never upgrades.
+func SyncSample(data, version, logFile string) (string, bool) {
+	if version == "" || version == "dev" {
+		return data, false
+	}
+	first, _, _ := strings.Cut(data, "\n")
+	marker, ok := strings.CutPrefix(first, versionMarker)
+	if !ok {
+		return data, false // not written by the installer
+	}
+	if compareVersions(strings.TrimSpace(marker), version) >= 0 {
+		return data, false // same or newer
+	}
+
+	present := make(map[string]bool)
+	for _, line := range strings.Split(data, "\n") {
+		line = strings.TrimSpace(strings.TrimPrefix(strings.TrimSpace(line), "#"))
+		if name, _, ok := strings.Cut(line, "="); ok {
+			present[strings.TrimSpace(name)] = true
+		}
+	}
+
+	var b strings.Builder
+	b.WriteString(versionMarker + version + "\n")
+	rest := strings.TrimPrefix(data, first)
+	b.WriteString(strings.TrimRight(rest, "\n"))
+	b.WriteString("\n")
+	for _, e := range sampleEntries(logFile) {
+		if !present[e.name] {
+			fmt.Fprintf(&b, "\n# Added by gpu-turnstile %s:\n", version)
+			writeEntry(&b, e)
+		}
+	}
+	out := b.String()
+	return out, out != data
+}
+
+// compareVersions orders two vX.Y.Z version strings. Unparseable versions
+// (including "dev") sort before any release.
+func compareVersions(a, b string) int {
+	pa, oka := parseVersion(a)
+	pb, okb := parseVersion(b)
+	if oka != okb {
+		if oka {
+			return 1
+		}
+		return -1
+	}
+	for i := range pa {
+		if pa[i] != pb[i] {
+			if pa[i] > pb[i] {
+				return 1
+			}
+			return -1
+		}
+	}
+	return 0
+}
+
+func parseVersion(v string) ([3]int, bool) {
+	var out [3]int
+	v = strings.TrimPrefix(strings.TrimSpace(v), "v")
+	parts := strings.Split(v, ".")
+	if len(parts) != 3 {
+		return out, false
+	}
+	for i, p := range parts {
+		n, err := strconv.Atoi(p)
+		if err != nil || n < 0 {
+			return out, false
+		}
+		out[i] = n
+	}
+	return out, true
+}