Add rudimentary ingredient parsing and merging

src/commands/groceries.rs

@@ -85,15 +85,42 @@ where
     Ok(ingredients.into_iter().flatten().collect())
 }
 
-fn merge_ingredients(mut ingredients: Vec<(Ingredient, String)>) -> Vec<(Ingredient, String)> {
-    ingredients.sort();
-
-    // TODO actual merging
-
-    ingredients
+fn merge_ingredients(mut ingredients: Vec<(Ingredient, String)>) -> Vec<(Ingredient, Vec<String>)> {
+    if ingredients.is_empty() {
+        return vec![];
     }
 
-fn prepare_grocery_list(ingredients: &Vec<(Ingredient, String)>) -> Result<String> {
+    // Prime merged_ingredients with the first ingredient in sorted order.
+    ingredients.sort_by(|(a, _), (b, _)| {
+        a.name.cmp(&b.name).then_with(|| {
+            // inefficient, but not so bad for now
+            a.unit.to_string().cmp(&b.unit.to_string())
+        })
+    });
+    let (mut merged_ingredients, ingredients): (Vec<(Ingredient, Vec<String>)>, _) = {
+        let v = ingredients.split_off(1);
+        (
+            ingredients.into_iter().map(|(i, s)| (i, vec![s])).collect(),
+            v,
+        )
+    };
+
+    for (ingredient, recipe) in ingredients {
+        // If it can be summed to the last item of merged_ingredients, do it;
+        // else append it
+        let (last_i, last_rs) = merged_ingredients.last_mut().unwrap();
+        if last_i.name == ingredient.name && last_i.unit == ingredient.unit {
+            last_i.amount += ingredient.amount;
+            last_rs.push(recipe);
+        } else {
+            merged_ingredients.push((ingredient, vec![recipe]));
+        }
+    }
+
+    merged_ingredients
+}
+
+fn prepare_grocery_list(ingredients: &Vec<(Ingredient, Vec<String>)>) -> Result<String> {
     let mut out = String::new();
     use std::fmt::Write;
 
@@ -103,9 +130,11 @@ fn prepare_grocery_list(ingredients: &Vec<(Ingredient, String)>) -> Result<Strin
         chrono::Local::now().format("%Y-%m-%d").to_string()
     )?;
     writeln!(out)?; // leave an empty line
-    for ingredient in ingredients {
-        let ingredient_s = ingredient.0 .0.as_str();
-        writeln!(out, "- [ ] {} ({})", ingredient_s, ingredient.1)?;
+    for (ingredient, recipes) in ingredients {
+        writeln!(out, "- [ ] {}", ingredient)?;
+        for recipe in recipes {
+            writeln!(out, "  * {}", recipe)?;
+        }
     }
 
     Ok(out)

src/recipe.rs

@@ -60,9 +60,19 @@ pub struct Recipe {
     //pub nutrition: Nutrition,
 }
 
-#[derive(Deserialize, Debug, Ord, Eq, PartialEq, PartialOrd)]
-#[serde(rename_all = "camelCase")]
-pub struct Ingredient(pub String);
+#[derive(Debug, PartialEq, PartialOrd)]
+pub struct Ingredient {
+    pub name: String,
+    pub amount: f64,
+    pub unit: Unit,
+}
+
+#[derive(Debug, Eq, PartialEq, PartialOrd)]
+pub enum Unit {
+    None,
+    Kilogram,
+    Liter,
+}
 
 #[derive(Deserialize, Debug)]
 #[serde(rename_all = "camelCase")]
@@ -130,3 +140,144 @@ impl Recipe {
             .unwrap_or_else(|| self.prep_time + self.cook_time.unwrap_or(Duration::zero()))
     }
 }
+
+impl<'de> Deserialize<'de> for Ingredient {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        deserializer.deserialize_str(IngredientVisitor)
+    }
+}
+
+struct IngredientVisitor;
+
+impl<'de> serde::de::Visitor<'de> for IngredientVisitor {
+    type Value = Ingredient;
+
+    fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
+    where
+        E: serde::de::Error,
+    {
+        use std::cmp::min;
+
+        let quantity_regex_start: regex::Regex =
+            regex::Regex::new(r"^(?P<v>[0-9,\.]+)\s*(?P<u>\w+)?\s+(?P<i>.*)").unwrap();
+        let quantity_regex_end: regex::Regex =
+            regex::Regex::new(r"(?P<i>.*?)\s+(?P<v>[0-9,\.]+)\s*(?P<u>\w+)?$").unwrap();
+
+        if let Some(captures) = quantity_regex_start
+            .captures(value)
+            .or_else(|| quantity_regex_end.captures(value))
+        {
+            let v = captures.name("v").unwrap().as_str();
+            let um = captures.name("u");
+            let u = um.map(|u| u.as_str()).unwrap_or("");
+            let im = captures.name("i").unwrap();
+            let i = im.as_str();
+
+            let (amount, unit) = Self::parse_quantity(v, u)?;
+            let name = match unit {
+                Unit::None => {
+                    // pick the longest string including what was recognized by the regex as the possible unit
+                    let start = um
+                        .map(|um| min(um.start(), im.start()))
+                        .unwrap_or_else(|| im.start());
+                    &value[start..im.end()]
+                }
+                _ => i,
+            }
+            .to_owned();
+
+            Ok(Ingredient { name, amount, unit })
+        } else {
+            Ok(Ingredient {
+                name: value.to_owned(),
+                amount: 1.0,
+                unit: Unit::None,
+            })
+        }
+    }
+
+    fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+        formatter.write_str("a parseable ingredient name with an optional mass or volume quantity at the beginning or end")
+    }
+}
+
+impl IngredientVisitor {
+    fn parse_quantity<E>(value: &str, unit: &str) -> Result<(f64, Unit), E>
+    where
+        E: serde::de::Error,
+    {
+        let mut v = value
+            .parse::<f64>()
+            .map_err(|e| serde::de::Error::custom(e.to_string()))?;
+        let u = match unit.to_lowercase().as_str() {
+            "kg" => Unit::Kilogram,
+            "g" | "gr" => {
+                v = v / 1000.0;
+                Unit::Kilogram
+            }
+            "hg" => {
+                v = v / 10.0;
+                Unit::Kilogram
+            }
+            "l" => Unit::Liter,
+            "dl" => {
+                v = v / 10.0;
+                Unit::Liter
+            }
+            "cl" => {
+                v = v / 100.0;
+                Unit::Liter
+            }
+            "ml" => {
+                v = v / 1000.0;
+                Unit::Liter
+            }
+            "tl" => {
+                v = v / 1000.0 * 5.0;
+                Unit::Liter
+            }
+            "el" => {
+                v = v / 1000.0 * 15.0;
+                Unit::Liter
+            }
+            "tsp" => {
+                v = v / 1000.0 * 4.93;
+                Unit::Liter
+            }
+            "tblsp" => {
+                v = v / 1000.0 * 14.79;
+                Unit::Liter
+            }
+            _ => Unit::None,
+        };
+
+        Ok((v, u))
+    }
+}
+
+impl core::fmt::Display for Ingredient {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "{amount:.3}{unit} {name}",
+            name = self.name,
+            amount = self.amount,
+            unit = self.unit
+        )
+    }
+}
+
+impl core::fmt::Display for Unit {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let u: &dyn core::fmt::Display = match self {
+            Unit::Kilogram => &"kg",
+            Unit::Liter => &"L",
+            Unit::None => &"",
+        };
+
+        write!(f, "{}", u)
+    }
+}