CLI command architecture and DB-backed model update syncing (#397)

crates-cli/yaak-cli/src/utils/json.rs

@@ -0,0 +1,110 @@
+use serde::Serialize;
+use serde::de::DeserializeOwned;
+use serde_json::{Map, Value};
+
+type JsonResult<T> = std::result::Result<T, String>;
+
+pub fn is_json_shorthand(input: &str) -> bool {
+    input.trim_start().starts_with('{')
+}
+
+pub fn parse_json_object(raw: &str, context: &str) -> JsonResult<Value> {
+    let value: Value = serde_json::from_str(raw)
+        .map_err(|error| format!("Invalid JSON for {context}: {error}"))?;
+
+    if !value.is_object() {
+        return Err(format!("JSON payload for {context} must be an object"));
+    }
+
+    Ok(value)
+}
+
+pub fn parse_optional_json(
+    json_flag: Option<String>,
+    json_shorthand: Option<String>,
+    context: &str,
+) -> JsonResult<Option<Value>> {
+    match (json_flag, json_shorthand) {
+        (Some(_), Some(_)) => Err(format!(
+            "Cannot provide both --json and positional JSON for {context}"
+        )),
+        (Some(raw), None) => parse_json_object(&raw, context).map(Some),
+        (None, Some(raw)) => parse_json_object(&raw, context).map(Some),
+        (None, None) => Ok(None),
+    }
+}
+
+pub fn parse_required_json(
+    json_flag: Option<String>,
+    json_shorthand: Option<String>,
+    context: &str,
+) -> JsonResult<Value> {
+    parse_optional_json(json_flag, json_shorthand, context)?.ok_or_else(|| {
+        format!("Missing JSON payload for {context}. Use --json or positional JSON")
+    })
+}
+
+pub fn require_id(payload: &Value, context: &str) -> JsonResult<String> {
+    payload
+        .get("id")
+        .and_then(|value| value.as_str())
+        .filter(|value| !value.is_empty())
+        .map(|value| value.to_string())
+        .ok_or_else(|| format!("{context} requires a non-empty \"id\" field"))
+}
+
+pub fn validate_create_id(payload: &Value, context: &str) -> JsonResult<()> {
+    let Some(id_value) = payload.get("id") else {
+        return Ok(());
+    };
+
+    match id_value {
+        Value::String(id) if id.is_empty() => Ok(()),
+        _ => Err(format!(
+            "{context} create JSON must omit \"id\" or set it to an empty string"
+        )),
+    }
+}
+
+pub fn apply_merge_patch<T>(existing: &T, patch: &Value, id: &str, context: &str) -> JsonResult<T>
+where
+    T: Serialize + DeserializeOwned,
+{
+    let mut base = serde_json::to_value(existing)
+        .map_err(|error| format!("Failed to serialize existing model for {context}: {error}"))?;
+    merge_patch(&mut base, patch);
+
+    let Some(base_object) = base.as_object_mut() else {
+        return Err(format!("Merged payload for {context} must be an object"));
+    };
+    base_object.insert("id".to_string(), Value::String(id.to_string()));
+
+    serde_json::from_value(base)
+        .map_err(|error| format!("Failed to deserialize merged payload for {context}: {error}"))
+}
+
+fn merge_patch(target: &mut Value, patch: &Value) {
+    match patch {
+        Value::Object(patch_map) => {
+            if !target.is_object() {
+                *target = Value::Object(Map::new());
+            }
+
+            let target_map =
+                target.as_object_mut().expect("merge_patch target expected to be object");
+
+            for (key, patch_value) in patch_map {
+                if patch_value.is_null() {
+                    target_map.remove(key);
+                    continue;
+                }
+
+                let target_entry = target_map.entry(key.clone()).or_insert(Value::Null);
+                merge_patch(target_entry, patch_value);
+            }
+        }
+        _ => {
+            *target = patch.clone();
+        }
+    }
+}