Add snapshot function back

contracts/martian-field/src/contract.rs

@@ -81,6 +81,9 @@ fn execute_callback(deps: DepsMut, env: Env, info: MessageInfo, msg: CallbackMsg
         CallbackMsg::AssertHealth {
             user_addr,
         } => callbacks::assert_health(deps, env, user_addr),
+        CallbackMsg::Snapshot {
+            user_addr,
+        } => callbacks::snapshot(deps, env, user_addr),
     }
 }
 

contracts/martian-field/src/execute_callbacks.rs

@@ -7,10 +7,10 @@ use cosmwasm_std::{
 
 use cw_asset::{Asset, AssetInfo, AssetList};
 
-use fields_of_mars::martian_field::{Position,  State};
+use fields_of_mars::martian_field::{Position, Snapshot, State};
 
 use crate::health::compute_health;
-use crate::state::{CACHED_USER_ADDR, CONFIG, POSITION, STATE};
+use crate::state::{CACHED_USER_ADDR, CONFIG, POSITION, SNAPSHOT, STATE};
 
 static DEFAULT_BOND_UNITS_PER_SHARE_BONDED: Uint128 = Uint128::new(1_000_000);
 static DEFAULT_DEBT_UNITS_PER_ASSET_BORROWED: Uint128 = Uint128::new(1_000_000);
@@ -590,3 +590,21 @@ pub fn assert_health(deps: DepsMut, env: Env, user_addr: Addr) -> StdResult<Resp
         .add_attribute("action", "martian_field :: callback :: assert_health")
         .add_event(event))
 }
+
+pub fn snapshot(deps: DepsMut, env: Env, user_addr: Addr) -> StdResult<Response> {
+    let config = CONFIG.load(deps.storage)?;
+    let state = STATE.load(deps.storage)?;
+    let position = POSITION.load(deps.storage, &user_addr).unwrap_or_default();
+    let health = compute_health(&deps.querier, &env, &config, &state, &position)?;
+
+    let snapshot = Snapshot {
+        time: env.block.time.seconds(),
+        height: env.block.height,
+        position: position.into(),
+        health,
+    };
+
+    SNAPSHOT.save(deps.storage, &user_addr, &snapshot)?;
+
+    Ok(Response::new().add_attribute("action", "martian_field :: callback :: snapshot"))
+}

contracts/martian-field/src/state.rs

@@ -1,10 +1,13 @@
 use cosmwasm_std::{Addr};
 use cw_storage_plus::{Item, Map};
 
-use fields_of_mars::martian_field::{Config, Position, State};
+use fields_of_mars::martian_field::{Config, Position, Snapshot, State};
 
 pub const CONFIG: Item<Config> = Item::new("config");
 pub const STATE: Item<State> = Item::new("state");
 pub const POSITION: Map<&Addr, Position> = Map::new("position");
 
 pub const CACHED_USER_ADDR: Item<Addr> = Item::new("cached_user_addr");
+
+// TODO: delete this
+pub const SNAPSHOT: Map<&Addr, Snapshot> = Map::new("snapshot");

packages/fields-of-mars/src/martian_field.rs

@@ -188,6 +188,19 @@ pub struct Health {
     pub ltv: Option<Decimal>,
 }
 
+/// Every time the user invokes `update_position`, we record a snaphot of the position
+///
+/// This snapshot does have any impact on the contract's normal functioning. Rather it is used by
+/// the frontend to calculate PnL. Once we have the infrastructure for calculating PnL off-chain 
+/// available, we will migrate the contract to delete this
+#[derive(Default, Serialize, Deserialize, Clone, Debug, PartialEq, JsonSchema)]
+pub struct Snapshot {
+    pub time: u64,
+    pub height: u64,
+    pub position: PositionUnchecked,
+    pub health: Health,
+}
+
 //--------------------------------------------------------------------------------------------------
 // Message and response types
 //--------------------------------------------------------------------------------------------------
@@ -359,6 +372,11 @@ pub mod msg {
         AssertHealth {
             user_addr: Addr,
         },
+        /// See the comment on struct `Snapshot`. This callback should be removed at some point
+        /// after launch when our tx indexing infrastructure is ready
+        Snapshot {
+            user_addr: Addr,
+        },
     }
 
     impl CallbackMsg {