Get config

We need the following values in order to build a `Client`:

* GitHub token
* Repo owner
* Repo name

Get the token from a command-line argument, or else the Git config, or
else an environment variable.

Get the repo identifiers from the repo's remote URL. Use the remote
specified as a command-line argument, otherwise get it from the Git
config, or else default to "origin".

TODO: Only try to get the owner-name pair from the remote if a comment
ID was given, not if a URL argument was passed.

3 files changed, 85 insertions, 3 deletions

diff --git a/src/bin/git-sugpatch.rs b/src/bin/git-sugpatch.rs
index 0ad8874..2a9b348 100644
--- a/src/bin/git-sugpatch.rs
+++ b/src/bin/git-sugpatch.rs
@@ -2,11 +2,14 @@ use std::env;
 use std::process;
 
 use github_suggestion::{Client, SuggestionUrl};
+use github_suggestion_cli::config::Config;
 
 
 fn main() {
     let args: Vec<_> = env::args().collect();
 
+    let config = Config::get(&args).unwrap();
+
     if args.len() < 2 {
         process::exit(111);
     }
@@ -14,9 +17,9 @@ fn main() {
     let url: SuggestionUrl = args[1].parse().unwrap();
 
     let client = Client::new(
-        env!("GITHUB_TOKEN"),
-        &url.owner,
-        &url.repo,
+        &config.github_token,
+        &config.owner,
+        &config.repo,
     ).unwrap();
 
     let suggestion = client.fetch(&url.comment_id).unwrap();
diff --git a/src/config.rs b/src/config.rs
new file mode 100644
index 0000000..321ea50
--- /dev/null
+++ b/src/config.rs
@@ -0,0 +1,77 @@
+use std::env;
+
+use getopts::Options;
+use git2::Repository;
+use thiserror::Error;
+
+use crate::owner_repo::{self, OwnerRepo};
+
+
+const GIT_CONFIG_PREFIX: &'static str = "githubSuggestion.";
+
+#[derive(Debug, Error)]
+pub enum Error {
+    #[error("Unable to parse arguments")]
+    Opts(#[from] getopts::Fail),
+
+    #[error("Error getting environment variable")]
+    EnvVar(#[from] env::VarError),
+
+    #[error(transparent)]
+    OwnerRepo(#[from] owner_repo::Error),
+
+    #[error(transparent)]
+    Git(#[from] git2::Error),
+}
+
+#[derive(Debug)]
+pub struct Config {
+    pub github_token: String,
+    pub owner: String,
+    pub repo: String,
+}
+
+impl Config {
+    // fn from_args(args: &env::Args) -> Result<Self, Error> {
+    pub fn get(args: &[String]) -> Result<Self, Error> {
+        let mut opts = Options::new();
+
+        opts.optopt("", "github-token", "", "TOKEN");
+        opts.optopt("", "remote", "", "REMOTE");
+
+        let opt_matches = opts.parse(&args[1..])?;
+
+        let git_config = Repository::open(".")?.config()?;
+
+        let github_token = match opt_matches.opt_str("github-token") {
+            Some(t) => Ok(t),
+            None =>
+                match git_config.get_string(&git_config_key("githubToken")) {
+                    Err(e) if e.code() == git2::ErrorCode::NotFound =>
+                        env::var("GITHUB_TOKEN")
+                            .map_err(|e| Error::EnvVar(e)),
+                    r => r.map_err(|e| Error::Git(e)),
+                },
+        }?;
+
+        let remote = match opt_matches.opt_str("remote") {
+            Some(r) => Ok(Some(r)),
+            None => match git_config.get_string(&git_config_key("remote")) {
+                Err(e) if e.code() == git2::ErrorCode::NotFound => Ok(None),
+                r => r.map(|r| Some(r)),
+            },
+        }?;
+
+        let o_r = OwnerRepo::from_remote(remote.as_deref())?;
+
+        Ok(Config {
+            github_token,
+            owner: o_r.owner,
+            repo: o_r.repo,
+        })
+    }
+}
+
+fn git_config_key(key: &str) -> String {
+    format!("{}.{}", GIT_CONFIG_PREFIX, key)
+}
diff --git a/src/lib.rs b/src/lib.rs
index a08be2b..494c389 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,3 +1,5 @@
 #![warn(rust_2018_idioms)]
 
+pub mod config;
+
 pub(crate) mod owner_repo;