refactor(root): seperate into small files

root/shell.go

@@ -0,0 +1,101 @@
+package root
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"strconv"
+	"strings"
+)
+
+type procInfo struct {
+	pid  int
+	ppid int
+	comm string
+}
+
+// detectShell identifies the shell type by scanning parent processes
+func detectShell() string {
+	pid := os.Getppid()
+	for i := 0; i < 5 && pid > 1; i++ {
+		data, err := os.ReadFile(fmt.Sprintf("/proc/%d/comm", pid))
+		if err == nil {
+			comm := strings.ToLower(strings.TrimSpace(string(data)))
+			if strings.Contains(comm, "zsh") {
+				return "zsh"
+			}
+			if strings.Contains(comm, "bash") {
+				return "bash"
+			}
+			if strings.Contains(comm, "fish") {
+				return "fish"
+			}
+		}
+
+		data, err = os.ReadFile(fmt.Sprintf("/proc/%d/stat", pid))
+		if err != nil {
+			break
+		}
+		fields := strings.Fields(string(data))
+		if len(fields) > 3 {
+			ppid, _ := strconv.Atoi(fields[3])
+			if ppid == pid || ppid <= 1 {
+				break
+			}
+			pid = ppid
+		} else {
+			break
+		}
+	}
+
+	s := os.Getenv("SHELL")
+	if strings.Contains(s, "zsh") {
+		return "zsh"
+	}
+	return "bash"
+}
+
+// getActiveInnerShell retrieves the most recently started shell in the process tree
+// example: getActiveInnerShell(1234, "bash")
+func getActiveInnerShell(rootPid int, defaultShell string) string {
+	cmd := exec.Command("ps", "-e", "-o", "pid,ppid,comm")
+	out, err := cmd.Output()
+	if err != nil {
+		return defaultShell
+	}
+
+	lines := strings.Split(string(out), "\n")
+	childrenMap := make(map[int][]procInfo)
+
+	for _, line := range lines {
+		fields := strings.Fields(line)
+		if len(fields) >= 3 && fields[0] != "PID" {
+			pid, _ := strconv.Atoi(fields[0])
+			ppid, _ := strconv.Atoi(fields[1])
+			comm := strings.ToLower(strings.Join(fields[2:], " "))
+			childrenMap[ppid] = append(childrenMap[ppid], procInfo{pid, ppid, comm})
+		}
+	}
+
+	var findDeepest func(pid int, current string) string
+	findDeepest = func(pid int, current string) string {
+		shell := current
+		for _, child := range childrenMap[pid] {
+			childShell := shell
+			if strings.Contains(child.comm, "zsh") {
+				childShell = "zsh"
+			}
+			if strings.Contains(child.comm, "bash") {
+				childShell = "bash"
+			}
+			if strings.Contains(child.comm, "fish") {
+				childShell = "fish"
+			}
+			if deepest := findDeepest(child.pid, childShell); deepest != "" {
+				shell = deepest
+			}
+		}
+		return shell
+	}
+	return findDeepest(rootPid, defaultShell)
+}