added env file and the ability to set a interval for data to be grabbed

.env

@@ -0,0 +1 @@
+UPDATE_INTERVAL=12

Cargo.lock

@@ -17,6 +17,21 @@ version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f26201604c87b1e01bd3d98f8d5d9a8fcbb815e8cedb41ffccbeb4bf593a35fe"
 
+[[package]]
+name = "android-tzdata"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e999941b234f3131b00bc13c22d06e8c5ff726d1b6318ac7eb276997bbb4fef0"
+
+[[package]]
+name = "android_system_properties"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "819e7219dbd41043ac279b19830f2efc897156490d7fd6ea916720117ee66311"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "autocfg"
 version = "1.1.0"
@@ -80,6 +95,21 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 
+[[package]]
+name = "chrono"
+version = "0.4.26"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ec837a71355b28f6556dbd569b37b3f363091c0bd4b2e735674521b4c5fd9bc5"
+dependencies = [
+ "android-tzdata",
+ "iana-time-zone",
+ "js-sys",
+ "num-traits",
+ "time",
+ "wasm-bindgen",
+ "winapi",
+]
+
 [[package]]
 name = "console"
 version = "0.15.7"
@@ -109,6 +139,12 @@ version = "0.8.4"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "e496a50fda8aacccc86d7529e2c1e0892dbd0f898a6b5645b5561b89c3210efa"
 
+[[package]]
+name = "dotenv"
+version = "0.15.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "77c90badedccf4105eca100756a0b1289e191f6fcbdadd3cee1d2f614f97da8f"
+
 [[package]]
 name = "encode_unicode"
 version = "0.3.6"
@@ -328,6 +364,29 @@ dependencies = [
  "tokio-native-tls",
 ]
 
+[[package]]
+name = "iana-time-zone"
+version = "0.1.57"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "2fad5b825842d2b38bd206f3e81d6957625fd7f0a361e345c30e01a0ae2dd613"
+dependencies = [
+ "android_system_properties",
+ "core-foundation-sys",
+ "iana-time-zone-haiku",
+ "js-sys",
+ "wasm-bindgen",
+ "windows",
+]
+
+[[package]]
+name = "iana-time-zone-haiku"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f31827a206f56af32e590ba56d5d2d085f558508192593743f16b2306495269f"
+dependencies = [
+ "cc",
+]
+
 [[package]]
 name = "idna"
 version = "0.4.0"
@@ -453,7 +512,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "927a765cd3fc26206e66b296465fa9d3e5ab003e651c1b3c060e7956d96b19d2"
 dependencies = [
  "libc",
- "wasi",
+ "wasi 0.11.0+wasi-snapshot-preview1",
  "windows-sys 0.48.0",
 ]
 
@@ -461,6 +520,8 @@ dependencies = [
 name = "mtg_seller_bot"
 version = "0.1.0"
 dependencies = [
+ "chrono",
+ "dotenv",
  "indicatif",
  "reqwest",
  "serde",
@@ -486,6 +547,15 @@ dependencies = [
  "tempfile",
 ]
 
+[[package]]
+name = "num-traits"
+version = "0.2.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f30b0abd723be7e2ffca1272140fac1a2f084c77ec3e123c192b66af1ee9e6c2"
+dependencies = [
+ "autocfg",
+]
+
 [[package]]
 name = "num_cpus"
 version = "1.16.0"
@@ -842,6 +912,17 @@ dependencies = [
  "windows-sys 0.48.0",
 ]
 
+[[package]]
+name = "time"
+version = "0.1.45"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1b797afad3f312d1c66a56d11d0316f916356d11bd158fbc6ca6389ff6bf805a"
+dependencies = [
+ "libc",
+ "wasi 0.10.0+wasi-snapshot-preview1",
+ "winapi",
+]
+
 [[package]]
 name = "tinyvec"
 version = "1.6.0"
@@ -997,6 +1078,12 @@ dependencies = [
  "try-lock",
 ]
 
+[[package]]
+name = "wasi"
+version = "0.10.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1a143597ca7c7793eff794def352d41792a93c481eb1042423ff7ff72ba2c31f"
+
 [[package]]
 name = "wasi"
 version = "0.11.0+wasi-snapshot-preview1"
@@ -1101,6 +1188,15 @@ version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"
 
+[[package]]
+name = "windows"
+version = "0.48.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "e686886bc078bc1b0b600cac0147aadb815089b6e4da64016cbd754b6342700f"
+dependencies = [
+ "windows-targets 0.48.1",
+]
+
 [[package]]
 name = "windows-sys"
 version = "0.45.0"

Cargo.toml

@@ -6,6 +6,8 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+chrono = "0.4.26"
+dotenv = "0.15.0"
 indicatif = "0.17.5"
 reqwest = { version = "0.11.18", features = ["json"] }
 serde = { version = "1.0.178", features = ["derive"]}

src/main.rs

@@ -1,44 +1,61 @@
+/// This program utilizes several external libraries to perform its functions, such as dotenv, serde, tokio, etc.
+use dotenv;
 use serde::{Deserialize, Serialize};
 use std::{collections::HashMap, env, fs::File, fs::OpenOptions, io::BufReader};
 use tokio::time::Duration;
 use indicatif::{ProgressBar, ProgressStyle};
 
-
+/// This structure defines a Card object, consisting of a name and a hashmap of prices.
-/// A struct to represent a Card returned from the API.
 #[derive(Serialize, Deserialize, Debug, Clone)]
 struct Card {
-    /// The name of the card.
     name: String,
-    /// The prices of the card in various formats.
     prices: HashMap<String, Option<String>>,
 }
 
-/// A struct to represent a Card from the local JSON file.
+/// This structure defines a CardFromFile object, consisting of a name, count, and a USD value.
 #[derive(Serialize, Deserialize, Debug, Clone)]
 struct CardFromFile {
-    /// The name of the card.
     name: String,
-    /// The count of this card.
     count: usize,
-    /// The value of this card in USD.
     usd_value: Option<String>,
 }
 
-/// A struct to represent a collection of Cards from the local JSON file.
+/// This structure defines a CardFile object, consisting of a vector of CardFromFile objects.
 #[derive(Serialize, Deserialize, Debug)]
 struct CardFile {
-    /// The list of cards.
     cards: Vec<CardFromFile>,
 }
 
-/// The main function.
+/// The main function of the program. It retrieves card price information from an external API and updates a local JSON file.
-///
+/// It accepts a path to a JSON file as an argument and also uses an environment variable, UPDATE_INTERVAL, to determine the frequency of its update cycle.
-/// This function reads a local JSON file of cards, sends an API request for each card to get the current price in USD,
-/// compares the fetched price with the stored price in the local file, and updates the file if there is any difference.
-///
-/// Note: There is a delay of 100ms between each API request as per the API rules.
 #[tokio::main]
-async fn main() -> Result<(), Box<std::io::Error>> {
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    dotenv::dotenv().ok();
+
+    // Retrieve the update interval from the .env file or return an error if not present.
+    let update_interval_str = match dotenv::var("UPDATE_INTERVAL") {
+        Ok(val) => val,
+        Err(_) => {
+            eprintln!("UPDATE_INTERVAL is not defined in the .env file");
+            return Err("UPDATE_INTERVAL is not defined in the .env file".into());
+        }
+    };
+    // Attempt to parse the update interval as a u64 or return an error if it fails.
+    let update_interval = match update_interval_str.parse::<u64>() {
+        Ok(val) => val,
+        Err(_) => {
+            eprintln!("UPDATE_INTERVAL is not a valid number");
+            return Err("UPDATE_INTERVAL is not a valid number".into());
+        }
+    };
+
+    let update_interval = std::time::Duration::from_secs(update_interval * 3600);
+
+    let mut interval = tokio::time::interval(update_interval);
+    loop {
+        interval.tick().await;
+
+        // Retrieve the file path from the program's arguments or return an error if not present.
         let args: Vec<String> = env::args().collect();
         if args.len() < 2 {
             eprintln!("Please provide the path to the JSON file as an argument.");
@@ -46,20 +63,12 @@ async fn main() -> Result<(), Box<std::io::Error>> {
         }
 
         let file_path = &args[1];
-    let file = match File::open(file_path) {
+        let file = File::open(file_path)?;
-        Ok(file) => file,
-        Err(error) => {
-            eprintln!("There was a problem opening the file: {:?}", error);
-            return Err(Box::new(std::io::Error::new(
-                std::io::ErrorKind::NotFound,
-                "File not found",
-            )));
-        }
-    };    
 
         let reader = BufReader::new(file);
-    let mut cards_data: CardFile = serde_json::from_reader(reader).unwrap();
+        let mut cards_data: CardFile = serde_json::from_reader(reader)?;
 
+        // Setting up a progress bar for visual representation of the card processing progress.
         let pb = ProgressBar::new(cards_data.cards.len() as u64);
         let style = ProgressStyle::default_bar()
             .template("{spinner:.green} [{elapsed_precise}] [{bar:40.cyan/blue}] {pos}/{len} ({eta})")
@@ -67,18 +76,15 @@ async fn main() -> Result<(), Box<std::io::Error>> {
         let style = style.progress_chars("#>-");
         pb.set_style(style);
 
+        // For each card in the input file, retrieve the current price information and update the local data if necessary.
         for card_from_file in &mut cards_data.cards {
             let request_url = format!(
                 "https://api.scryfall.com/cards/named?exact={}",
                 card_from_file.name
             );
-        let response = reqwest::get(&request_url).await
+            let response = reqwest::get(&request_url).await?;
-            .map_err(|err| std::io::Error::new(std::io::ErrorKind::Other, err.to_string()))?;
-    
-        let card: Card = response.json().await
-            .map_err(|err| std::io::Error::new(std::io::ErrorKind::Other, err.to_string()))?;
-
 
+            let card: Card = response.json().await?;
 
             if let Some(price) = card.prices.get("usd") {
                 if let Some(price_str) = price {
@@ -88,20 +94,21 @@ async fn main() -> Result<(), Box<std::io::Error>> {
                 }
             }
 
+            // Increment the progress bar and pause for a brief period.
             pb.inc(1);
             tokio::time::sleep(Duration::from_millis(100)).await;
         }
 
+        // Mark the progress bar as completed.
         pb.finish_with_message("Completed!");
 
+        // Write the updated card data back to the input file.
         let file = OpenOptions::new()
             .write(true)
             .truncate(true)
-        .open(file_path)
+            .open(file_path)?;
-        .unwrap();
 
-    serde_json::to_writer_pretty(file, &cards_data).unwrap();
+        serde_json::to_writer_pretty(file, &cards_data)?;
 
-    Ok(())
     }
-
+}