From c10362b5ff8a1ad06e471b9547e1b3e08bf69f50 Mon Sep 17 00:00:00 2001
From: Luis Ball <contact.luis@icloud.com>
Date: Mon, 29 Dec 2025 14:15:57 -0800
Subject: [PATCH] feat: add gh CLI helpers

Add src/gh_cli.rs module for GitHub CLI detection and installation
hints to help users create PRs when none exist for a branch.

New functions:
- is_gh_installed(): Check if gh CLI is available
- is_gh_authenticated(): Check if gh is logged in
- install_instructions(): Platform-specific install commands
- suggest_create_pr(): Print gh pr create command with hints
- prompt_create_pr(): Interactive PR creation prompt

The module handles non-TTY environments gracefully and provides
helpful messages when gh is not installed or not authenticated.

Includes 3 unit tests.
---
 src/gh_cli.rs | 142 ++++++++++++++++++++++++++++++++++++++++++++++++++
 src/lib.rs    |   1 +
 2 files changed, 143 insertions(+)
 create mode 100644 src/gh_cli.rs

diff --git a/src/gh_cli.rs b/src/gh_cli.rs
new file mode 100644
index 0000000..e6ad05d
--- /dev/null
+++ b/src/gh_cli.rs
@@ -0,0 +1,142 @@
+//! GitHub CLI detection and installation helpers
+//!
+//! Provides detection of the `gh` CLI and platform-specific installation
+//! instructions for helping users create PRs.
+
+use dialoguer::Confirm;
+use std::error::Error;
+use std::io::{self, IsTerminal};
+use std::process::Command;
+
+/// Check if the GitHub CLI (`gh`) is installed
+pub fn is_gh_installed() -> bool {
+    Command::new("gh")
+        .arg("--version")
+        .output()
+        .map(|o| o.status.success())
+        .unwrap_or(false)
+}
+
+/// Check if the GitHub CLI is authenticated
+pub fn is_gh_authenticated() -> bool {
+    Command::new("gh")
+        .args(["auth", "status"])
+        .output()
+        .map(|o| o.status.success())
+        .unwrap_or(false)
+}
+
+/// Get platform-specific installation instructions for the GitHub CLI
+pub fn install_instructions() -> &'static str {
+    #[cfg(target_os = "macos")]
+    {
+        "brew install gh"
+    }
+
+    #[cfg(target_os = "linux")]
+    {
+        "sudo apt install gh    # Debian/Ubuntu\n  sudo dnf install gh    # Fedora"
+    }
+
+    #[cfg(target_os = "windows")]
+    {
+        "winget install GitHub.cli"
+    }
+
+    #[cfg(not(any(target_os = "macos", target_os = "linux", target_os = "windows")))]
+    {
+        "See https://cli.github.com/manual/installation"
+    }
+}
+
+/// Print a suggestion to create a PR for a branch
+///
+/// Shows the `gh pr create` command and, if `gh` is not installed,
+/// provides installation instructions.
+pub fn suggest_create_pr(head: &str, base: &str) {
+    println!("No PR found for branch '{}'.\n", head);
+    println!("Create a PR with:");
+    println!("  gh pr create --base {} --head {}\n", base, head);
+
+    if !is_gh_installed() {
+        println!("Note: 'gh' CLI is not installed.\n");
+        println!("Install with:");
+        println!("  {}\n", install_instructions());
+        println!("After installing, run 'gh auth login' to authenticate.");
+    } else if !is_gh_authenticated() {
+        println!("Note: 'gh' CLI is not authenticated.\n");
+        println!("Run 'gh auth login' to authenticate.");
+    }
+}
+
+/// Prompt the user to create a PR and execute if confirmed
+///
+/// Returns `Ok(true)` if PR was created, `Ok(false)` if user declined or
+/// `gh` is not available, `Err` on failure.
+///
+/// In non-interactive mode (no TTY), always returns `Ok(false)`.
+pub fn prompt_create_pr(head: &str, base: &str) -> Result<bool, Box<dyn Error>> {
+    // Check if we're in an interactive terminal
+    if !io::stdout().is_terminal() {
+        suggest_create_pr(head, base);
+        return Ok(false);
+    }
+
+    // Check if gh is installed
+    if !is_gh_installed() {
+        suggest_create_pr(head, base);
+        return Ok(false);
+    }
+
+    // Check if gh is authenticated
+    if !is_gh_authenticated() {
+        println!("No PR found for branch '{}'.\n", head);
+        println!("The 'gh' CLI is installed but not authenticated.");
+        println!("Run 'gh auth login' to authenticate, then try again.");
+        return Ok(false);
+    }
+
+    println!("No PR found for branch '{}'.\n", head);
+
+    let create = Confirm::new()
+        .with_prompt(format!("Create a PR from '{}' into '{}'?", head, base))
+        .default(true)
+        .interact()?;
+
+    if !create {
+        return Ok(false);
+    }
+
+    println!("\nCreating PR...\n");
+
+    let status = Command::new("gh")
+        .args(["pr", "create", "--base", base, "--head", head])
+        .status()?;
+
+    Ok(status.success())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_install_instructions_not_empty() {
+        let instructions = install_instructions();
+        assert!(!instructions.is_empty());
+        // Should contain some actionable command
+        assert!(instructions.contains("install") || instructions.contains("cli.github.com"));
+    }
+
+    #[test]
+    fn test_is_gh_installed_returns_bool() {
+        // Just verify it returns a bool without panicking
+        let _result = is_gh_installed();
+    }
+
+    #[test]
+    fn test_is_gh_authenticated_returns_bool() {
+        // Just verify it returns a bool without panicking
+        let _result = is_gh_authenticated();
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index 9f36d21..b7240b4 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,4 +1,5 @@
 pub mod api;
+pub mod gh_cli;
 pub mod git;
 pub mod graph;
 pub mod identifier;