fix: improve object simulator. (#799)

Issues fixed:

- The simulator doesn't show masses (total and per-item)
- The "add item" button is missing when the product items list is empty.
- When selecting an existing example or bookmark, we'd like to fill its
name in the new bookmark text input.
- We'd also like a more meaningful query string representation than what
we currently have.
- We want to render the steps impact distribution chart in the sidebar.

public/data/object/examples.json

@@ -1,4 +1,12 @@
 [
+  {
+    "id": "0d08a9ff-5683-4d3d-a7b8-dce74f37cd3b",
+    "name": "Produit vide",
+    "category": "",
+    "query": {
+      "processes": []
+    }
+  },
   {
     "id": "7d78d30e-7c35-451f-b8ab-e590f39ed0e8",
     "name": "Chaise",

public/data/object/processes.json

@@ -35,7 +35,6 @@
     "id": "3295b2a5-328a-4c00-b046-e2ddeb0da823",
     "name": "Plastic frame (PP)",
     "display_name": "Composant en plastique (PP)",
-    "density": 900,
     "unit": "kg",
     "impacts": {
       "acd": 0,

src/Data/Bookmark.elm

@@ -163,7 +163,8 @@ toQueryDescription db bookmark =
 
         Object objectQuery ->
             objectQuery
-                |> ObjectQuery.toString
+                |> ObjectQuery.toString db.object.processes
+                |> Result.withDefault "N/A"
 
         Textile textileQuery ->
             textileQuery

src/Data/Object/Process.elm

@@ -6,7 +6,6 @@ module Data.Object.Process exposing
     , encode
     , encodeId
     , findById
-    , idToString
     )
 
 import Data.Impact as Impact exposing (Impacts)
@@ -36,7 +35,7 @@ decodeProcess : Decoder Impact.Impacts -> Decoder Process
 decodeProcess impactsDecoder =
     Decode.succeed Process
         |> Pipe.required "comment" Decode.string
-        |> Pipe.required "density" Decode.float
+        |> Pipe.optional "density" Decode.float 1
         |> Pipe.required "display_name" Decode.string
         |> Pipe.required "id" decodeId
         |> Pipe.required "impacts" impactsDecoder

src/Data/Object/Query.elm

@@ -20,6 +20,7 @@ import Base64
 import Data.Object.Process as Process exposing (Process)
 import Json.Decode as Decode exposing (Decoder)
 import Json.Encode as Encode
+import Result.Extra as RE
 import Url.Parser as Parser exposing (Parser)
 
 
@@ -120,21 +121,23 @@ updateItem newItem query =
     }
 
 
-toString : Query -> String
-toString query =
-    query.items
-        |> List.map
-            (\i ->
-                (i.amount
-                    |> amountToFloat
-                    |> String.fromFloat
-                )
-                    ++ " "
-                    ++ (i.processId
-                            |> Process.idToString
-                       )
+toString : List Process -> Query -> Result String String
+toString processes =
+    .items
+        >> List.map
+            (\item ->
+                item.processId
+                    |> Process.findById processes
+                    |> Result.map
+                        (\process ->
+                            String.fromFloat (amountToFloat item.amount)
+                                ++ process.unit
+                                ++ " "
+                                ++ process.displayName
+                        )
             )
-        |> String.join " - "
+        >> RE.combine
+        >> Result.map (String.join ", ")
 
 
 

src/Data/Object/Simulator.elm

@@ -1,17 +1,33 @@
 module Data.Object.Simulator exposing
-    ( availableProcesses
+    ( Results(..)
+    , availableProcesses
     , compute
-    , computeItemImpacts
+    , emptyResults
+    , expandItems
+    , extractImpacts
+    , extractItems
+    , extractMass
+    , toStepsImpacts
     )
 
-import Data.Impact as Impact exposing (Impacts)
+import Data.Impact as Impact exposing (Impacts, noStepsImpacts)
+import Data.Impact.Definition as Definition
 import Data.Object.Process as Process exposing (Process)
 import Data.Object.Query as Query exposing (Item, Query)
+import Mass exposing (Mass)
 import Quantity
 import Result.Extra as RE
 import Static.Db exposing (Db)
 
 
+type Results
+    = Results
+        { impacts : Impacts
+        , items : List Results
+        , mass : Mass
+        }
+
+
 availableProcesses : Db -> Query -> List Process
 availableProcesses { object } query =
     let
@@ -22,19 +38,86 @@ availableProcesses { object } query =
         |> List.filter (\{ id } -> not (List.member id usedIds))
 
 
-compute : Db -> Query -> Result String Impacts
+compute : Db -> Query -> Result String Results
 compute db query =
     query.items
-        |> List.map (computeItemImpacts db)
+        |> List.map (computeItemResults db)
         |> RE.combine
-        |> Result.map Impact.sumImpacts
+        |> Result.map
+            (List.foldr
+                (\(Results { impacts, mass }) (Results acc) ->
+                    Results
+                        { acc
+                            | impacts = Impact.sumImpacts [ impacts, acc.impacts ]
+                            , items = Results { impacts = impacts, items = [], mass = mass } :: acc.items
+                            , mass = Quantity.sum [ mass, acc.mass ]
+                        }
+                )
+                emptyResults
+            )
 
 
-computeItemImpacts : Db -> Item -> Result String Impacts
-computeItemImpacts { object } { amount, processId } =
+computeItemResults : Db -> Item -> Result String Results
+computeItemResults { object } { amount, processId } =
     processId
         |> Process.findById object.processes
         |> Result.map
-            (.impacts
-                >> Impact.mapImpacts (\_ -> Quantity.multiplyBy (Query.amountToFloat amount))
+            (\process ->
+                Results
+                    { impacts =
+                        process.impacts
+                            |> Impact.mapImpacts (\_ -> Quantity.multiplyBy (Query.amountToFloat amount))
+                    , items = []
+                    , mass =
+                        Mass.kilograms <|
+                            if process.unit == "kg" then
+                                Query.amountToFloat amount
+
+                            else
+                                -- apply density
+                                Query.amountToFloat amount * process.density
+                    }
             )
+
+
+emptyResults : Results
+emptyResults =
+    Results
+        { impacts = Impact.empty
+        , items = []
+        , mass = Quantity.zero
+        }
+
+
+expandItems : Db -> Query -> Result String (List ( Query.Amount, Process ))
+expandItems db =
+    .items
+        >> List.map (\{ amount, processId } -> ( amount, processId ))
+        >> List.map (RE.combineMapSecond (Process.findById db.object.processes))
+        >> RE.combine
+
+
+extractImpacts : Results -> Impacts
+extractImpacts (Results { impacts }) =
+    impacts
+
+
+extractItems : Results -> List Results
+extractItems (Results { items }) =
+    items
+
+
+extractMass : Results -> Mass
+extractMass (Results { mass }) =
+    mass
+
+
+toStepsImpacts : Definition.Trigram -> Results -> Impact.StepsImpacts
+toStepsImpacts trigram results =
+    { noStepsImpacts
+      -- FIXME: for now, as we only have materials, assign everything to the material step
+        | materials =
+            extractImpacts results
+                |> Impact.getImpact trigram
+                |> Just
+    }