1 files changed, 48 insertions, 2 deletions
diff --git a/completion/completion.go b/completion/completion.go
index 6aad9d1..f3d76d7 100644
--- a/completion/completion.go
+++ b/completion/completion.go
@@ -2,15 +2,61 @@ package completion
 
 import (
 	_ "embed"
+	"errors"
+	"fmt"
+	"github.com/ewy1/pik/paths"
 	"github.com/ewy1/pik/spool"
+	"os"
+	"path/filepath"
+	"strings"
 )
 
 //go:embed completion.sh
 var completionCode string
 
+var completionFormat = `
+# %s
+%s
+`
+
+var completionComment = "\n# pik completion (installed by `pik --install-completion`)\n"
+
 var completionCodeByShell = map[string]string{
-	"bash": ". <(pik --completion)",
-	"zsh":  `autoload -Uz compinit && compinit && source <(pik --completion)`,
+	"bash": ". <(pik --completion)\n\n",
+	"zsh":  `autoload -Uz compinit && compinit && source <(pik --completion)\n\n`,
+}
+
+var completionFileByShell = map[string]string{
+	"bash": ".bashrc",
+	"zsh":  ".zshrc",
+}
+
+var AlreadyInstalledError = errors.New("completion already installed")
+
+func Add(shell string) error {
+	f := filepath.Join(paths.HomeDir.String(), completionFileByShell[shell])
+	content, err := os.ReadFile(f)
+	if err != nil {
+		return err
+	}
+	if strings.Contains(string(content), strings.TrimSpace(completionCodeByShell[shell])) {
+		return AlreadyInstalledError
+	}
+	fd, err := os.OpenFile(f, os.O_APPEND|os.O_WRONLY, 0600)
+	defer fd.Close()
+	if err != nil {
+		return err
+	}
+	_, err = fd.Write([]byte(fmt.Sprintf(completionFormat, completionComment, completionCodeByShell[shell])))
+	if err != nil {
+		return err
+	}
+	successMessage(shell, f)
+	return nil
+}
+
+func successMessage(shell string, file string) {
+	_, _ = spool.Print("Installed completion for %s in %s\n", shell, file)
 }
 
 func Echo() error {