From feadba1a65dcbd6233e1e547f980c3981d65bb93 Mon Sep 17 00:00:00 2001
From: Jacob VanDomelen <Jacob.Vandome15@gmail.com>
Date: Fri, 31 May 2019 23:07:13 -0700
Subject: [PATCH] #1 Finished FileLinked implementation.

---
 gemla/src/bracket/mod.rs     | 10 +++--
 gemla/src/file_linked/mod.rs | 75 ++++++++++++++++++++++++------------
 gemla/src/main.rs            |  5 +++
 gemla/src/tree/mod.rs        |  1 +
 4 files changed, 63 insertions(+), 28 deletions(-)

diff --git a/gemla/src/bracket/mod.rs b/gemla/src/bracket/mod.rs
index ae77763..49f7ffb 100644
--- a/gemla/src/bracket/mod.rs
+++ b/gemla/src/bracket/mod.rs
@@ -1,6 +1,7 @@
 mod state;
 
 use super::tree;
+use super::file_linked::FileLinked;
 
 use uuid::Uuid;
 use std::str::FromStr;
@@ -40,15 +41,18 @@ fn build_tree(h: u32) -> Option<Box<tree::Tree<Uuid>>> {
 /// TODO: Explain reasoning for bracket system against genetic algorithm.
 pub fn run_bracket() {
 	let mut height = 1;
-	let mut tree: tree::Tree<Uuid> = *build_tree(height).expect("Error getting result from build_tree.");
+	let mut tree = FileLinked::new(*build_tree(height).expect("Error getting result from build_tree"), "temp")
+		.expect("Unable to create file linked object from tree");
+
 
 	// Building tree one node at a time, appending to the top.
 	loop {
 		println!("=========================================");
 		println!("Running bracket...");
 		height += 1;
-		tree = tree::Tree::new(Uuid::new_v4(), Some(Box::new(tree)), build_tree(height));
-		tree.run_simulation();
+		tree.replace(tree::Tree::new(Uuid::new_v4(), Some(Box::new(tree.readonly().clone())), build_tree(height)))
+			.expect("Error building up tree node");
+		tree.readonly().run_simulation();
 
 		if height == 3 {
 			println!("{}\n\n", tree);
diff --git a/gemla/src/file_linked/mod.rs b/gemla/src/file_linked/mod.rs
index 378bbff..3d6ed39 100644
--- a/gemla/src/file_linked/mod.rs
+++ b/gemla/src/file_linked/mod.rs
@@ -1,6 +1,6 @@
 use std::fs;
 use std::str::FromStr;
-use std::fmt::Display;
+use std::fmt;
 use std::string::String;
 use std::io::Read;
 use std::io::Write;
@@ -10,44 +10,57 @@ pub struct FileLinked<T> {
 	path: String
 }
 
-impl<T: FromStr + Display> FileLinked<T> {
+impl<T> FileLinked<T> where T: FromStr + fmt::Display + Default {
 	pub fn from_file(path: &str) -> Result<FileLinked<T>, String> {
-		let meta = fs::metadata(path)
-			.or(Err(format!("Path {} does not exist.", path)))?;
-		
-		if meta.is_file() {
-			let mut file = fs::OpenOptions::new().read(true).open(path)
-				.or(Err(format!("Unable to open file {}", path)))?;
-			let mut s = String::new();
-			file.read_to_string(&mut s)
-				.or(Err(String::from("Unable to read from file.")))?;
+		let meta = fs::metadata(path);
 
-			let val = T::from_str(&s).or(Err(String::from("Unable to parse value from file.")))?;
+		match &meta {
+			Ok(m) if m.is_file() => {
+				let mut file = fs::OpenOptions::new().read(true).open(path)
+					.or(Err(format!("Unable to open file {}", path)))?;
+				let mut s = String::new();
+				file.read_to_string(&mut s)
+					.or(Err(String::from("Unable to read from file.")))?;
 
-			Ok(FileLinked {
-				val,
-				path: String::from(path)
-			})
-		} else {
-			Err(format!("{} is not a file.", path))
+				let val = T::from_str(&s).or(Err(String::from("Unable to parse value from file.")))?;
+
+				Ok(FileLinked {
+					val,
+					path: String::from(path)
+				})
+			},
+			Ok(_) => {
+				Err(format!("{} is not a file.", path))
+			},
+			_ => {
+				let result = FileLinked {
+					val: T::default(),
+					path: String::from(path)
+				};
+
+				result.write_data()?;
+
+				Ok(result)
+			}
 		}
 	}
 
-	pub fn new(val: T, path: &str) -> FileLinked<T> {
+	pub fn new(val: T, path: &str) -> Result<FileLinked<T>, String> {
 		let result = FileLinked {
 			val,
 			path: String::from(path)
 		};
 
-		result.write_data();
+		result.write_data()?;
 
-		result
+		Ok(result)
 	}
 
 	pub fn write_data(&self) -> Result<(), String> {
 		let mut file = fs::OpenOptions::new()
 					.write(true)
-					.create_new(true)
+					.create(true)
+					.truncate(true)
 					.open(&self.path)
 					.or(Err(format!("Unable to open path {}", self.path)))?;
 
@@ -61,11 +74,23 @@ impl<T: FromStr + Display> FileLinked<T> {
 		&self.val
 	}
 
-	pub fn mutate<U, F: FnOnce(&mut T) -> U>(&mut self, op: F) -> U {
+	pub fn mutate<U, F: FnOnce(&mut T) -> U>(&mut self, op: F) -> Result<U, String> {
 		let result = op(&mut self.val);
 
-		self.write_data();
+		self.write_data()?;
 
-		result
+		Ok(result)
+	}
+
+	pub fn replace(&mut self, val: T) -> Result<(), String>{
+		self.val = val;
+
+		self.write_data()
+	}
+}
+
+impl<T: fmt::Display> fmt::Display for FileLinked<T> {
+	fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+		write!(f, "{}", self.val)
 	}
 }
\ No newline at end of file
diff --git a/gemla/src/main.rs b/gemla/src/main.rs
index 9abefcf..af13f13 100644
--- a/gemla/src/main.rs
+++ b/gemla/src/main.rs
@@ -28,6 +28,11 @@ fn main() {
 			println!("{} is a valid directory!", directory);
 			println!("Building tree for {}.", directory);
 			bracket::run_bracket();
+
+			println!("\n\nReading tree from temp file.");
+			let tree: file_linked::FileLinked<tree::Tree<uuid::Uuid>> = file_linked::FileLinked::from_file("temp")
+				.expect("Unable to read tree from existing file");
+			println!("Value read from file:\n{}", tree);
 		},
 		Ok(_) => println!("{} is not a valid directory!", directory),
 		_ => println!("{} does not exist!", directory)
diff --git a/gemla/src/tree/mod.rs b/gemla/src/tree/mod.rs
index 6f2b5d4..464ce4a 100644
--- a/gemla/src/tree/mod.rs
+++ b/gemla/src/tree/mod.rs
@@ -2,6 +2,7 @@ use std::fmt;
 use std::str::FromStr;
 use regex::Regex;
 
+#[derive(Default, Clone)]
 pub struct Tree<T> {
 	pub val: T,
 	pub left: Option<Box<Tree<T>>>,