importer feature

crates/adapters/importer/src/parsers/json.rs

@@ -0,0 +1,43 @@
+use serde_json::Value;
+use crate::{ImportError, types::ParsedFile};
+
+pub fn parse_json(bytes: &[u8]) -> Result<ParsedFile, ImportError> {
+    let value: Value = serde_json::from_slice(bytes)
+        .map_err(|e| ImportError::Json(e.to_string()))?;
+
+    let arr = value.as_array()
+        .ok_or_else(|| ImportError::Json("expected a JSON array".into()))?;
+
+    if arr.is_empty() {
+        return Err(ImportError::Empty);
+    }
+
+    let first = arr[0].as_object()
+        .ok_or_else(|| ImportError::Json("array elements must be objects".into()))?;
+    let columns: Vec<String> = first.keys().cloned().collect();
+
+    if columns.is_empty() {
+        return Err(ImportError::NoHeader);
+    }
+
+    let rows: Vec<Vec<String>> = arr.iter()
+        .enumerate()
+        .map(|(idx, item)| {
+            let obj = item.as_object()
+                .ok_or_else(|| ImportError::Json(format!("element at index {} is not an object", idx)))?;
+            Ok(columns.iter()
+                .map(|col| obj.get(col).map(value_to_string).unwrap_or_default())
+                .collect())
+        })
+        .collect::<Result<_, ImportError>>()?;
+
+    Ok(ParsedFile { columns, rows })
+}
+
+fn value_to_string(v: &Value) -> String {
+    match v {
+        Value::String(s) => s.clone(),
+        Value::Null => String::new(),
+        other => other.to_string(),
+    }
+}