🎉 Add support for --amend

Cargo.toml

@@ -13,14 +13,17 @@ readme = "readme.md"
 license = "MIT"
 
 [dependencies]
-termion = "1.0"
+termion = "4"
 log-update = "~0.1.0"
 default-editor = "~0.1.0"
 emoji-commit-type = "~0.1.1"
 git2 = "~0.15.0"
 structopt = "~0.3"
 ansi_term = "~0.12"
 
+[dev-dependencies]
+tempfile = "~3.14.0"
+
 [profile.release]
 codegen-units = 1
 lto = true

src/main.rs

@@ -2,7 +2,7 @@ use std::env;
 use std::error::Error;
 use std::fmt;
 use std::fs::File;
-use std::io::{BufRead, BufReader, Seek, Write, stderr, stdin};
+use std::io::{Seek, Write, stderr, stdin};
 use std::process::{Command, exit};
 use std::path::PathBuf;
 use std::str::FromStr;
@@ -12,12 +12,14 @@ use termion::input::TermRead;
 use termion::raw::IntoRawMode;
 
 use emoji_commit_type::CommitType;
+use message::{git_parse_existing_message, git_message_is_empty};
 use log_update::LogUpdate;
 use structopt::StructOpt;
 use ansi_term::Colour::{RGB, Green, Red, White};
 
 mod commit_rules;
 mod git;
+mod message;
 
 impl fmt::Display for commit_rules::CommitRuleValidationResult {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
@@ -42,14 +44,14 @@ fn commit_type_at_index (index: u8) -> Option<CommitType> {
     CommitType::iter_variants().nth(index as usize)
 }
 
-fn select_emoji() -> Option<&'static str> {
+fn select_emoji(initial_selected: Option<CommitType>) -> Option<&'static str> {
     let mut log_update = LogUpdate::new(stderr()).unwrap();
     let mut raw_output = stderr().into_raw_mode().unwrap();
 
     let mut key_stream = stdin().keys();
 
     let mut aborted = false;
-    let mut selected = CommitType::Breaking;
+    let mut selected = initial_selected.unwrap_or(CommitType::Breaking);
 
     // Clear possibly printed "hint" from git
     log_update.render("").unwrap();
@@ -73,14 +75,14 @@ fn select_emoji() -> Option<&'static str> {
     if aborted { None } else { Some(selected.emoji()) }
 }
 
-fn collect_commit_message(selected_emoji: &'static str, launch_editor: &mut bool) -> Option<String> {
+fn collect_commit_message(selected_emoji: &'static str, initial_message: Option<String>, launch_editor: &mut bool) -> Option<String> {
     let mut log_update = LogUpdate::new(stderr()).unwrap();
     let mut raw_output = stderr().into_raw_mode().unwrap();
 
     let mut key_stream = stdin().keys();
 
     let mut aborted = false;
-    let mut input = String::new();
+    let mut input = initial_message.unwrap_or(String::new());
 
     loop {
         let rule_text = commit_rules::check_message(&input)
@@ -143,33 +145,30 @@ fn launch_git_with_self_as_editor() {
     run_cmd(Command::new("git").arg("commit").env("GIT_EDITOR", self_path))
 }
 
-fn git_message_is_empty(file: &mut File) -> bool {
-    for line in BufReader::new(file).lines() {
-        let line = line.expect("Failed to read line from git message file");
-
-        if !line.starts_with('#') && !line.is_empty()  {
-            return false;
-        }
-    }
-    true
-}
-
 fn collect_information_and_write_to_file(out_path: PathBuf) {
     let mut file = File::options().read(true).write(true).create(true).open(&out_path).unwrap();
+    let mut initial_message: Option<String> = None;
+    let mut initial_commit_type: Option<CommitType> = None;
 
     if !git_message_is_empty(&mut file) {
-        launch_default_editor(out_path);
-        return;
+        file.rewind().unwrap();
+        if let Some((commit_type, message)) = git_parse_existing_message(&mut file) {
+            initial_commit_type = Some(commit_type);
+            initial_message = Some(message);
+        } else {
+            launch_default_editor(out_path);
+            return;
+        }
     }
 
-    let maybe_emoji = select_emoji();
+    let maybe_emoji = select_emoji(initial_commit_type);
     if maybe_emoji == None {
         abort();
     }
 
     if let Some(emoji) = maybe_emoji {
         let mut launch_editor = false;
-        let maybe_message = collect_commit_message(emoji, &mut launch_editor);
+        let maybe_message = collect_commit_message(emoji, initial_message, &mut launch_editor);
         if maybe_message == None {
             abort();
         }