refactor: extract shared parseRecordLine to eliminate duplication

Extract record line parsing into a shared parseRecordLine function in
types.go, replacing duplicated parsing logic in aggregate.go and db.go.
Also simplifies lastKernelFromFile to use the shared function.

Task: a6e5c545-a37d-41a8-8a98-f3edb28ab662
Amp-Thread-ID: https://ampcode.com/threads/T-019ca323-dde1-73ac-97f0-cebfae5922a5
Co-authored-by: Amp <amp@ampcode.com>

4 files changed, 136 insertions, 63 deletions

diff --git a/internal/goprecords/aggregate.go b/internal/goprecords/aggregate.go
index ba446cb..e75d486 100644
--- a/internal/goprecords/aggregate.go
+++ b/internal/goprecords/aggregate.go
@@ -6,7 +6,6 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
-	"strconv"
 	"strings"
 )
 
@@ -82,35 +81,14 @@ func processRecordsFile(ctx context.Context, path, host string, out *Aggregates)
 			return ctx.Err()
 		default:
 		}
-		line := strings.TrimSpace(sc.Text())
-		if line == "" {
+		rec, ok := parseRecordLine(sc.Text())
+		if !ok {
 			continue
 		}
-		parts := strings.SplitN(line, ":", 3)
-		if len(parts) != 3 {
-			continue
-		}
-		uptime, _ := strconv.ParseUint(parts[0], 10, 64)
-		bootTime, _ := strconv.ParseUint(parts[1], 10, 64)
-		osStr := parts[2]
-		uname := osStr
-		if i := strings.Index(osStr, " "); i > 0 {
-			uname = osStr[:i]
-		}
-		osMajor := uname + " "
-		rest := osStr
-		if i := strings.Index(osStr, " "); i >= 0 {
-			rest = osStr[i+1:]
-		}
-		if j := strings.Index(rest, "."); j >= 0 {
-			osMajor += rest[:j] + "..."
-		} else {
-			osMajor += rest + "..."
-		}
-		out.Host[host].AddRecord(uptime, bootTime)
-		getOrNewAggregate(out.Kernel, osStr).AddRecord(uptime, bootTime)
-		getOrNewAggregate(out.KernelName, uname).AddRecord(uptime, bootTime)
-		getOrNewAggregate(out.KernelMajor, osMajor).AddRecord(uptime, bootTime)
+		out.Host[host].AddRecord(rec.Uptime, rec.BootTime)
+		getOrNewAggregate(out.Kernel, rec.OS).AddRecord(rec.Uptime, rec.BootTime)
+		getOrNewAggregate(out.KernelName, rec.KernelName).AddRecord(rec.Uptime, rec.BootTime)
+		getOrNewAggregate(out.KernelMajor, rec.KernelMajor).AddRecord(rec.Uptime, rec.BootTime)
 	}
 	if err := sc.Err(); err != nil {
 		return fmt.Errorf("scan %s: %w", path, err)
@@ -137,18 +115,13 @@ func lastKernelFromFile(path string) (string, error) {
 	var lastOS string
 	sc := bufio.NewScanner(f)
 	for sc.Scan() {
-		line := strings.TrimSpace(sc.Text())
-		if line == "" {
-			continue
-		}
-		parts := strings.SplitN(line, ":", 3)
-		if len(parts) != 3 {
+		rec, ok := parseRecordLine(sc.Text())
+		if !ok {
 			continue
 		}
-		bootTime, _ := strconv.ParseUint(parts[1], 10, 64)
-		if bootTime >= maxBoot {
-			maxBoot = bootTime
-			lastOS = parts[2]
+		if rec.BootTime >= maxBoot {
+			maxBoot = rec.BootTime
+			lastOS = rec.OS
 		}
 	}
 	return lastOS, sc.Err()
diff --git a/internal/goprecords/db.go b/internal/goprecords/db.go
index 18fadf5..c11cdb0 100644
--- a/internal/goprecords/db.go
+++ b/internal/goprecords/db.go
@@ -7,7 +7,6 @@ import (
 	"fmt"
 	"os"
 	"path/filepath"
-	"strconv"
 	"strings"
 
 	_ "modernc.org/sqlite"
@@ -96,32 +95,11 @@ func ImportFromDir(ctx context.Context, db *sql.DB, statsDir string) error {
 		}
 		sc := bufio.NewScanner(f)
 		for sc.Scan() {
-			line := strings.TrimSpace(sc.Text())
-			if line == "" {
+			rec, ok := parseRecordLine(sc.Text())
+			if !ok {
 				continue
 			}
-			parts := strings.SplitN(line, ":", 3)
-			if len(parts) != 3 {
-				continue
-			}
-			uptimeSec, _ := strconv.ParseInt(parts[0], 10, 64)
-			bootTime, _ := strconv.ParseInt(parts[1], 10, 64)
-			osStr := parts[2]
-			osKernelName := osStr
-			if i := strings.Index(osStr, " "); i > 0 {
-				osKernelName = osStr[:i]
-			}
-			osMajor := osKernelName + " "
-			rest := osStr
-			if i := strings.Index(osStr, " "); i >= 0 {
-				rest = osStr[i+1:]
-			}
-			if j := strings.Index(rest, "."); j >= 0 {
-				osMajor += rest[:j] + "..."
-			} else {
-				osMajor += rest + "..."
-			}
-			_, err := insert.ExecContext(ctx, host, uptimeSec, bootTime, osStr, osKernelName, osMajor)
+			_, err := insert.ExecContext(ctx, host, rec.Uptime, rec.BootTime, rec.OS, rec.KernelName, rec.KernelMajor)
 			if err != nil {
 				f.Close()
 				return fmt.Errorf("insert: %w", err)
diff --git a/internal/goprecords/parse_test.go b/internal/goprecords/parse_test.go
index 304b06e..700440d 100644
--- a/internal/goprecords/parse_test.go
+++ b/internal/goprecords/parse_test.go
@@ -51,6 +51,84 @@ func TestParseMetric(t *testing.T) {
 	}
 }
 
+func TestParseRecordLine(t *testing.T) {
+	tests := []struct {
+		in   string
+		want recordLine
+		ok   bool
+	}{
+		{
+			"12345:1700000000:Linux 6.5.0-generic",
+			recordLine{
+				Uptime:      12345,
+				BootTime:    1700000000,
+				OS:          "Linux 6.5.0-generic",
+				KernelName:  "Linux",
+				KernelMajor: "Linux 6...",
+			},
+			true,
+		},
+		{
+			"  99:100:FreeBSD 14.0-RELEASE  ",
+			recordLine{
+				Uptime:      99,
+				BootTime:    100,
+				OS:          "FreeBSD 14.0-RELEASE",
+				KernelName:  "FreeBSD",
+				KernelMajor: "FreeBSD 14...",
+			},
+			true,
+		},
+		{
+			"500:200:SingleToken",
+			recordLine{
+				Uptime:      500,
+				BootTime:    200,
+				OS:          "SingleToken",
+				KernelName:  "SingleToken",
+				KernelMajor: "SingleToken SingleToken...",
+			},
+			true,
+		},
+		{
+			"100:200:Linux 6.5.0:extra",
+			recordLine{
+				Uptime:      100,
+				BootTime:    200,
+				OS:          "Linux 6.5.0:extra",
+				KernelName:  "Linux",
+				KernelMajor: "Linux 6...",
+			},
+			true,
+		},
+		{
+			"abc:def:Linux 6.5.0",
+			recordLine{
+				Uptime:      0,
+				BootTime:    0,
+				OS:          "Linux 6.5.0",
+				KernelName:  "Linux",
+				KernelMajor: "Linux 6...",
+			},
+			true,
+		},
+		{"", recordLine{}, false},
+		{"   ", recordLine{}, false},
+		{"only:two", recordLine{}, false},
+		{"no-colons-at-all", recordLine{}, false},
+	}
+	for _, tt := range tests {
+		got, ok := parseRecordLine(tt.in)
+		if ok != tt.ok {
+			t.Errorf("parseRecordLine(%q) ok=%v, want %v", tt.in, ok, tt.ok)
+			continue
+		}
+		if tt.ok && got != tt.want {
+			t.Errorf("parseRecordLine(%q) = %+v, want %+v", tt.in, got, tt.want)
+		}
+	}
+}
+
 func TestParseOutputFormat(t *testing.T) {
 	tests := []struct {
 		in   string
diff --git a/internal/goprecords/types.go b/internal/goprecords/types.go
index 05a68f8..ae8a059 100644
--- a/internal/goprecords/types.go
+++ b/internal/goprecords/types.go
@@ -75,6 +75,15 @@ func NewHostAggregate(name, lastKernel string) *HostAggregate {
 	}
 }
 
+// recordLine holds the parsed fields from a single uptimed record line.
+type recordLine struct {
+	Uptime      uint64
+	BootTime    uint64
+	OS          string
+	KernelName  string
+	KernelMajor string
+}
+
 // tableRow is one row in the report table.
 type tableRow struct {
 	Pos        string
@@ -250,6 +259,41 @@ func ParseOutputFormat(s string) (OutputFormat, error) {
 	}
 }
 
+func parseRecordLine(line string) (recordLine, bool) {
+	line = strings.TrimSpace(line)
+	if line == "" {
+		return recordLine{}, false
+	}
+	parts := strings.SplitN(line, ":", 3)
+	if len(parts) != 3 {
+		return recordLine{}, false
+	}
+	uptime, _ := strconv.ParseUint(parts[0], 10, 64)
+	bootTime, _ := strconv.ParseUint(parts[1], 10, 64)
+	osStr := parts[2]
+	kernelName := osStr
+	if i := strings.Index(osStr, " "); i > 0 {
+		kernelName = osStr[:i]
+	}
+	kernelMajor := kernelName + " "
+	rest := osStr
+	if i := strings.Index(osStr, " "); i >= 0 {
+		rest = osStr[i+1:]
+	}
+	if j := strings.Index(rest, "."); j >= 0 {
+		kernelMajor += rest[:j] + "..."
+	} else {
+		kernelMajor += rest + "..."
+	}
+	return recordLine{
+		Uptime:      uptime,
+		BootTime:    bootTime,
+		OS:          osStr,
+		KernelName:  kernelName,
+		KernelMajor: kernelMajor,
+	}, true
+}
+
 func wordWrap(s string, lineLimit int) string {
 	if lineLimit <= 0 || len(s) <= lineLimit {
 		return s