feat(pacman): implement Manager interface for pacman package manager

Adds full pacman wrapper with:
- All Manager interface methods (Install, Remove, Purge, Upgrade, Update,
  List, Search, Info, IsInstalled, Version, Available)
- Linux implementation using exec.CommandContext
- Non-linux stubs returning ErrUnsupportedPlatform
- Output parsing for -Q, -Ss, -Si formats
- Options support: WithSudo, WithAssumeYes, WithDryRun, WithRoot
- Unit tests for parsing and argument building

pacman/parse.go

@@ -0,0 +1,105 @@
+package pacman
+
+import (
+	"strings"
+
+	"github.com/gogrlx/snack"
+)
+
+// parseList parses the output of `pacman -Q` into packages.
+// Each line is "name version".
+func parseList(output string) []snack.Package {
+	var pkgs []snack.Package
+	for _, line := range strings.Split(output, "\n") {
+		line = strings.TrimSpace(line)
+		if line == "" {
+			continue
+		}
+		parts := strings.Fields(line)
+		if len(parts) < 2 {
+			continue
+		}
+		pkgs = append(pkgs, snack.Package{
+			Name:      parts[0],
+			Version:   parts[1],
+			Installed: true,
+		})
+	}
+	return pkgs
+}
+
+// parseSearch parses the output of `pacman -Ss` into packages.
+// Format:
+//
+//	repo/name version [installed]
+//	    Description text
+func parseSearch(output string) []snack.Package {
+	var pkgs []snack.Package
+	lines := strings.Split(output, "\n")
+	for i := 0; i < len(lines); i++ {
+		line := lines[i]
+		if line == "" || strings.HasPrefix(line, " ") || strings.HasPrefix(line, "\t") {
+			continue
+		}
+		// repo/name version [installed]
+		parts := strings.Fields(line)
+		if len(parts) < 2 {
+			continue
+		}
+		repoName := strings.SplitN(parts[0], "/", 2)
+		pkg := snack.Package{
+			Version: parts[1],
+		}
+		if len(repoName) == 2 {
+			pkg.Repository = repoName[0]
+			pkg.Name = repoName[1]
+		} else {
+			pkg.Name = repoName[0]
+		}
+		for _, p := range parts[2:] {
+			if strings.Contains(p, "installed") {
+				pkg.Installed = true
+			}
+		}
+		// Next line is description
+		if i+1 < len(lines) {
+			desc := strings.TrimSpace(lines[i+1])
+			if desc != "" {
+				pkg.Description = desc
+				i++
+			}
+		}
+		pkgs = append(pkgs, pkg)
+	}
+	return pkgs
+}
+
+// parseInfo parses the output of `pacman -Si` into a Package.
+// Format is "Key : Value" lines.
+func parseInfo(output string) *snack.Package {
+	pkg := &snack.Package{}
+	for _, line := range strings.Split(output, "\n") {
+		idx := strings.Index(line, ":")
+		if idx < 0 {
+			continue
+		}
+		key := strings.TrimSpace(line[:idx])
+		val := strings.TrimSpace(line[idx+1:])
+		switch key {
+		case "Name":
+			pkg.Name = val
+		case "Version":
+			pkg.Version = val
+		case "Description":
+			pkg.Description = val
+		case "Architecture":
+			pkg.Arch = val
+		case "Repository":
+			pkg.Repository = val
+		}
+	}
+	if pkg.Name == "" {
+		return nil
+	}
+	return pkg
+}