Add logic for creating new savefile from legacy savefile if new one isn't present

backend/src/api/handler.rs

@@ -23,7 +23,7 @@ pub enum ApiMessage {
     OnChargeChange(f64), // battery fill amount: 0 = empty, 1 = full
     PowerVibeCheck,
     WaitForEmptyQueue(Callback<()>),
-    LoadSettings(u64, String, u64, String), // (path, name, variant, variant name)
+    LoadSettings(Option<(u64, String)>, Option<(u64, String, u64, String)>), // (legacy(game_id, name), current(path, name, variant, variant name))
     LoadVariant(u64, String), // (variant, variant name) -- path and name assumed to be for current profile
     LoadMainSettings,
     LoadSystemSettings,
@@ -45,13 +45,21 @@ impl core::fmt::Display for ApiMessage {
             Self::OnChargeChange(x) => write!(f, "OnChargeChange({:?})", x),
             Self::PowerVibeCheck => write!(f, "PowerVibeCheck"),
             Self::WaitForEmptyQueue(_) => write!(f, "WaitForEmptyQueue"),
-            Self::LoadSettings(path, name, variant, variant_name) => write!(f, "LoadSettings({}, {}, {}, {})", path, name, variant, variant_name),
-            Self::LoadVariant(variant, variant_name) => write!(f, "LoadVariant({}, {})", variant, variant_name),
+            Self::LoadSettings(path, name, variant, variant_name) => write!(
+                f,
+                "LoadSettings({}, {}, {}, {})",
+                path, name, variant, variant_name
+            ),
+            Self::LoadVariant(variant, variant_name) => {
+                write!(f, "LoadVariant({}, {})", variant, variant_name)
+            }
             Self::LoadMainSettings => write!(f, "LoadMainSettings"),
             Self::LoadSystemSettings => write!(f, "LoadSystemSettings"),
             Self::GetLimits(_) => write!(f, "GetLimits"),
             Self::GetProvider(s, _) => write!(f, "GetProvider({})", s),
-            Self::UploadCurrentVariant(id, user) => write!(f, "UploadCurrentVariant(id: {}, user: {})", id, user),
+            Self::UploadCurrentVariant(id, user) => {
+                write!(f, "UploadCurrentVariant(id: {}, user: {})", id, user)
+            }
         }
     }
 }
@@ -392,9 +400,7 @@ impl ApiMessageHandler {
                 messages.push(msg.to_string());
                 dirty |= self.process(settings, msg);
             }
-            if dirty
-            || dirty_echo
-            {
+            if dirty || dirty_echo {
                 dirty_echo = dirty; // echo only once
                 print_messages(&messages);
                 // run on_set
@@ -498,7 +504,61 @@ impl ApiMessageHandler {
                 self.on_empty.push(callback);
                 false
             }
-            ApiMessage::LoadSettings(id, name, variant_id, variant_name) => {
+            ApiMessage::LoadSettings(legacy_settings, current_settings) => {
+                /* Migration steps:
+                1. Modify to the frontend to send the game ID in this message (`id` here is the app
+                   ID).
+                2. Change game ID to app ID.
+                3. (Create and) call function to merge OldSettingsJson with existing FileJson, or
+                   use existing `From<OldSettingsJson> for FileJson` if this game doesn't have a
+                   save in the new format yet.
+                4. Let the rest of the code below work its magic.
+                */
+
+                // ===== migration logic =====
+                if legacy_settings.is_some() {
+                    let (legacy_game_id, legacy_name) = legacy_settings.unwrap();
+
+                    let legacy_file_path = format!("{legacy_game_id}.json");
+                    let legacy_file = crate::persist::OldSettingsJson::open(legacy_file_path)
+                        .expect("should be able to deserialzie legacy savefile format"); // TODO: don't panic on fail.
+
+                    if current_settings.is_some() {
+                        // A savefile in both the legacy and current format exist.
+                        let (id, name, variant_id, variant_name) = current_settings.unwrap();
+                        let path = format!("{}.ron", id);
+
+                        // 1. Parse `legacy_file` to into a settings variant.
+                        let migrated_settings_variant: crate::persist::SettingsJson =
+                            legacy_file.into();
+                        // 2. Insert the variant into the current settings file.
+                        match settings.load_file(
+                            path.into(),
+                            id,
+                            name,
+                            variant_id,
+                            variant_name,
+                            false,
+                        ) {
+                            Ok(success) => log::info!("Loaded settings file? {}", success),
+                            Err(e) => log::warn!("Load file err: {}", e),
+                        }
+                        settings.add_variant() //TODO: This.
+                    } else {
+                        // A savefile in the current format doesn't exist yet.
+                        // TODO: Parse it to the new format and save it.
+
+                        let app_id_from_game_id: u64;
+                        let new_path = format!("{app_id_from_game_id}.ron");
+
+                        let migrated_settings: crate::persist::FileJson = legacy_file.into();
+                        migrated_settings.save(new_path);
+                    }
+                } else if current_settings.is_some() {
+                    // ...
+                }
+                // ===========================
+
                 let path = format!("{}.ron", id);
                 if let Err(e) = settings.on_unload() {
                     print_errors("LoadSettings on_unload()", e);

backend/src/persist/error.rs

@@ -36,6 +36,14 @@ impl From<ron::error::Error> for RonError {
     }
 }
 
+impl From<serde_json::Error> for RonError {
+    fn from(_value: serde_json::Error) -> Self {
+        RonError::General(ron::Error::Message(String::from(
+            "TODO: make error handling in migration logic good. Specifically, make it so a json error can be used as a RonError instead of just returning this string",
+        )))
+    }
+}
+
 impl From<ron::error::SpannedError> for RonError {
     fn from(value: ron::error::SpannedError) -> Self {
         Self::Spanned(value)

backend/src/persist/migration.rs

@@ -0,0 +1,4 @@
+pub mod gpu;
+pub mod settings;
+
+pub const APP_ID_UNKNOWN: u64 = u64::MAX;

backend/src/persist/migration/gpu.rs

@@ -0,0 +1,26 @@
+use serde::{Deserialize, Serialize};
+
+use crate::persist::{GpuJson, MinMaxJson};
+
+#[derive(Serialize, Deserialize, Clone)]
+pub struct OldGpuJson {
+    pub fast_ppt: Option<u64>,
+    pub slow_ppt: Option<u64>,
+    pub clock_limits: Option<MinMaxJson<u64>>,
+    pub slow_memory: bool,
+    pub root: Option<String>,
+}
+
+impl From<OldGpuJson> for GpuJson {
+    fn from(old_gpu: OldGpuJson) -> Self {
+        Self {
+            fast_ppt: old_gpu.fast_ppt,
+            slow_ppt: old_gpu.slow_ppt,
+            tdp: None,
+            tdp_boost: None,
+            clock_limits: old_gpu.clock_limits.clone(),
+            memory_clock: None,
+            root: old_gpu.root.clone(),
+        }
+    }
+}

backend/src/persist/migration/settings.rs

@@ -0,0 +1,67 @@
+use std::collections::HashMap;
+
+use serde::{Deserialize, Serialize};
+
+use crate::persist::{
+    BatteryJson, CpuJson, DriverJson, FileJson, SerdeError, SettingsJson, LATEST_VERSION,
+};
+
+use super::gpu::OldGpuJson;
+
+#[derive(Serialize, Deserialize, Clone)]
+pub struct OldOnEventJson {
+    pub on_save: Option<String>,
+    pub on_load: Option<String>,
+    pub on_set: Option<String>,
+    pub on_resume: Option<String>,
+}
+
+#[derive(Serialize, Deserialize, Clone)]
+pub struct OldSettingsJson {
+    pub version: u64,
+    pub name: String,
+    pub persistent: bool,
+    pub cpus: Vec<CpuJson>,
+    pub gpu: OldGpuJson,
+    pub battery: BatteryJson,
+    pub provider: Option<DriverJson>,
+    pub events: Option<OldOnEventJson>,
+}
+
+impl From<OldSettingsJson> for SettingsJson {
+    fn from(old_settings: OldSettingsJson) -> Self {
+        Self {
+            version: old_settings.version,
+            name: format!("{} (migrated)", old_settings.name.clone()),
+            variant: 0,
+            persistent: old_settings.persistent,
+            cpus: old_settings.cpus.clone(),
+            gpu: old_settings.gpu.clone().into(),
+            battery: old_settings.battery.clone(),
+            provider: old_settings.provider.clone(),
+            tags: Vec::new(),
+        }
+    }
+}
+
+impl From<OldSettingsJson> for FileJson {
+    fn from(old_settings: OldSettingsJson) -> Self {
+        let mut variants = HashMap::new();
+        let variant = SettingsJson::from(old_settings.clone());
+        variants.insert(0, variant);
+
+        Self {
+            version: LATEST_VERSION,
+            name: old_settings.name.clone(),
+            app_id: super::APP_ID_UNKNOWN, // `u64::MAX`, sentinel value.
+            variants,
+        }
+    }
+}
+
+impl OldSettingsJson {
+    pub fn open<P: AsRef<std::path::Path>>(path: P) -> Result<Self, SerdeError> {
+        let mut file = std::fs::File::open(path).map_err(SerdeError::Io)?;
+        serde_json::from_reader(&mut file).map_err(|e| SerdeError::Serde(e.into()))
+    }
+}

backend/src/persist/mod.rs

@@ -5,6 +5,7 @@ mod error;
 mod file;
 mod general;
 mod gpu;
+mod migration;
 
 pub use battery::{BatteryEventJson, BatteryJson};
 pub use cpu::CpuJson;
@@ -12,7 +13,8 @@ pub use driver::DriverJson;
 pub use file::FileJson;
 pub use general::{MinMaxJson, SettingsJson};
 pub use gpu::GpuJson;
+pub use migration::{gpu::*, settings::*};
 
-pub use error::SerdeError;
+pub use error::{RonError, SerdeError};
 
 pub const LATEST_VERSION: u64 = 0;