update/downgrade v1 to V2

src/main.rs

@@ -0,0 +1,155 @@
+mod model_version_1;
+mod model_version_2;
+
+pub use crate::model_version_1::SaveVersion1;
+pub use crate::model_version_2::downgrade_to_v1;
+pub use crate::model_version_2::upgrade_to_v2;
+pub use crate::model_version_2::SaveVersion2;
+use platform_dirs::{AppDirs, AppUI};
+use serde_json::Value;
+use std::env;
+use std::fs::{create_dir_all, File};
+use std::io::prelude::*;
+use std::io::{self, BufReader, Read};
+use std::time::SystemTime;
+
+fn main() {
+    let args: Vec<String> = env::args().collect();
+    if args.len() >= 2 {
+        let verb = &args[1];
+
+        match verb.as_ref() {
+            "update" => update_cmd(),
+            "help" => help_cmd(false, ""),
+            "downgrade" => {
+                if args.len() >= 3 {
+                    let allow_downgrade = confirm(
+                        "Do you really want to downgrade your save? \
+                        You may experience data lost",
+                    )
+                    .unwrap();
+                    if allow_downgrade {
+                        let version: u64 = args[2]
+                            .parse::<u64>()
+                            .expect("ERROR: Cannot get version number");
+                        downgrade_cmd(version);
+                    } else {
+                        println!("Operation aborted");
+                    }
+                } else {
+                    help_cmd(true, "ERROR: The version number is missing")
+                }
+            }
+            _ => help_cmd(true, "ERROR: This verb is not allowed"),
+        }
+    } else {
+        help_cmd(true, "ERROR: The verb arg is missing");
+    }
+}
+
+fn help_cmd(has_error: bool, err: &str) {
+    if has_error {
+        eprintln!("{}", err);
+        println!("");
+    }
+    println!("Usage: save-updater.exe <verb> [args]\n");
+    println!("List of verbs:");
+    println!("   update                Update the Chronos file save");
+    println!("   downgrade <version>   Downgrade to a version");
+    println!("   help                  Show this screen");
+}
+
+fn downgrade_cmd(version: u64) {
+    let json_file = open_save_file().expect("ERROR: Cannot open save file");
+    let v: Value = serde_json::from_str(&json_file).expect("ERROR: Cannot parse save file");
+    let current_version: u64 = v["version"]
+        .as_u64()
+        .expect("ERROR: Error while parsing save version");
+    if version == (current_version - 1) && version > 0 {
+        add_to_backup(&json_file).expect("ERROR: Failed to create backup");
+        match version {
+            1 => {
+                let s: SaveVersion2 =
+                    serde_json::from_str(&json_file).expect("ERROR: Cannot parse save file");
+                let new_save = downgrade_to_v1(s);
+                let json =
+                    serde_json::to_string(&new_save).expect("ERROR: Fail to build new save file");
+                save_to_file(&json, "data.json").expect("ERROR: Fail to save updated file");
+                println!("INFO: Save file has been downgraded");
+            }
+            _ => eprintln!("ERROR: Version not supported"),
+        }
+    } else {
+        eprintln!("ERROR: Only downgrading to the previous version is allowed");
+    }
+}
+
+fn update_cmd() {
+    let json_file = open_save_file().expect("ERROR: Cannot open save file");
+    let v: Value = serde_json::from_str(&json_file).expect("ERROR: Cannot parse save file");
+    if v["version"] == 1 {
+        add_to_backup(&json_file).expect("ERROR: Failed to create backup");
+        let s: SaveVersion1 =
+            serde_json::from_str(&json_file).expect("ERROR: Cannot parse save file");
+        let new_save = start_upgrade_from_v1(s);
+        let json = serde_json::to_string(&new_save).expect("ERROR: Fail to build new save file");
+        save_to_file(&json, "data.json").expect("ERROR: Fail to save updated file");
+        println!("INFO: Save file is up-to-date");
+    } else {
+        println!("Save already up-to-date");
+    }
+}
+
+fn open_save_file() -> std::result::Result<std::string::String, &'static str> {
+    let app_dirs = AppDirs::new(Some("Chronos"), AppUI::CommandLine)
+        .expect("ERROR: Cannot get application data folder");
+    let path = app_dirs.config_dir.join("data").join("data.json");
+    if path.exists() {
+        let file = File::open(path).expect("ERROR: cannot open file");
+        let mut buf_reader = BufReader::new(file);
+        let mut contents = String::new();
+        buf_reader
+            .read_to_string(&mut contents)
+            .expect("cannot read file");
+        Ok(contents)
+    } else {
+        Err("Save file not found")
+    }
+}
+
+fn save_to_file(content: &String, filename: &str) -> std::io::Result<()> {
+    let app_dirs = AppDirs::new(Some("Chronos"), AppUI::CommandLine)
+        .expect("ERROR: Cannot get application data folder");
+    let path = app_dirs.config_dir.join("data").join(filename);
+    let mut file = File::create(path)?;
+    file.write_all(content.as_bytes())?;
+    Ok(())
+}
+
+fn confirm(msg: &str) -> std::io::Result<bool> {
+    println!("{}\nType 'yes', other input will be ignore", msg);
+    let mut buffer = String::new();
+    io::stdin().read_line(&mut buffer)?;
+    Ok(buffer.trim() == "yes")
+}
+
+fn add_to_backup(content: &String) -> std::io::Result<()> {
+    let app_dirs = AppDirs::new(Some("Chronos"), AppUI::CommandLine)
+        .expect("ERROR: Cannot get application data folder");
+    let path = app_dirs.config_dir.join("data").join("backup");
+    create_dir_all(&path)?;
+    let timestamp = SystemTime::now()
+        .duration_since(SystemTime::UNIX_EPOCH)
+        .expect("ERROR: Failed to get timestamp")
+        .as_secs();
+    let path = path.join(format!("{}.data.json", timestamp));
+    let mut file = File::create(path)?;
+    file.write_all(content.as_bytes())?;
+    Ok(())
+}
+
+fn start_upgrade_from_v1(save: SaveVersion1) -> SaveVersion2 {
+    println!("INFO: Starting upgrading from version 1 to version 2");
+    let save = upgrade_to_v2(save);
+    save
+}