Renaming files

`PathBuf` lets us check to see if a file
exists before writing to it, so we can
take advantage of that to make sure that
we don't overwrite a file that already
exists, even if the user has indicated
a title that would overwrite another file.

```
let mut i: usize = 0;
loop {
    let dest_filename = format!(
        "{}{}",
        filename,
        if i == 0 {
            "".to_string()
        } else {
            i.to_string()
        }
    );
    let mut dest = garden_path.join(dest_filename);
    dest.set_extension("md");
    if dest.exists() {
        i = i + 1;
    } else {
        fs::rename(garden_tmpfile, &dest)?;
        break;
    }
}
```

src/main.rs

@@ -38,7 +38,6 @@ fn main() -> Result<()> {
     color_eyre::install()?;
 
     let opt = Opt::from_args();
-    dbg!(&opt);
     let garden_path = match opt.garden_path {
         Some(pathbuf) => Ok(pathbuf),
         None => get_default_garden_dir().wrap_err("`garden_path` was not supplied"),

src/write.rs

@@ -1,7 +1,10 @@
 use color_eyre::{eyre::WrapErr, Result};
 use edit::{edit_file, Builder};
-use std::io::{Read, Seek, SeekFrom, Write};
 use std::path::PathBuf;
+use std::{
+    fs,
+    io::{Read, Seek, SeekFrom, Write},
+};
 
 const TEMPLATE: &[u8; 2] = b"# ";
 
@@ -16,7 +19,7 @@ pub fn write(garden_path: PathBuf, title: Option<String>) -> Result<()> {
     file.write_all(TEMPLATE)?;
     // let the user write whatever they want in their favorite editor
     // before returning to the cli and finishing up
-    edit_file(filepath)?;
+    edit_file(&filepath)?;
     // Read the user's changes back from the file into a string
     let mut contents = String::new();
     file.seek(SeekFrom::Start(0))?;
@@ -25,10 +28,9 @@ pub fn write(garden_path: PathBuf, title: Option<String>) -> Result<()> {
     // use `title` if the user passed it in,
     // otherwise try to find a heading in the markdown
     let document_title = title.or_else(|| {
-        dbg!("here");
         contents
             .lines()
-            .find(|v| dbg!(v).starts_with("# "))
+            .find(|v| v.starts_with("# "))
             // markdown headings are required to have `# ` with
             // at least one space
             .map(|maybe_line| maybe_line.trim_start_matches("# ").to_string())
@@ -40,8 +42,28 @@ pub fn write(garden_path: PathBuf, title: Option<String>) -> Result<()> {
         None => ask_for_filename(),
     }?;
 
-    dbg!(contents, filename);
-    todo!()
+    let mut i: usize = 0;
+    loop {
+        let dest_filename = format!(
+            "{}{}",
+            filename,
+            if i == 0 {
+                "".to_string()
+            } else {
+                i.to_string()
+            }
+        );
+        let mut dest = garden_path.join(dest_filename);
+        dest.set_extension("md");
+        if dest.exists() {
+            i = i + 1;
+        } else {
+            fs::rename(filepath, &dest)?;
+            break;
+        }
+    }
+
+    Ok(())
 }
 
 fn ask_for_filename() -> Result<String> {