importer feature

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

@@ -0,0 +1,49 @@
+use crate::{ImportError, types::ParsedFile};
+
+pub fn parse_csv(bytes: &[u8]) -> Result<ParsedFile, ImportError> {
+    if bytes.is_empty() {
+        return Err(ImportError::Empty);
+    }
+
+    let delimiter = detect_delimiter(bytes);
+    let mut rdr = csv::ReaderBuilder::new()
+        .delimiter(delimiter)
+        .from_reader(bytes);
+
+    let columns: Vec<String> = rdr
+        .headers()
+        .map_err(|e| ImportError::Csv(e.to_string()))?
+        .iter()
+        .map(|s| s.trim().to_string())
+        .collect();
+
+    if columns.is_empty() {
+        return Err(ImportError::NoHeader);
+    }
+
+    let rows: Vec<Vec<String>> = rdr
+        .records()
+        .map(|r| {
+            r.map_err(|e| ImportError::Csv(e.to_string()))
+                .map(|rec| {
+                    let mut cells: Vec<String> = rec.iter().map(|f| f.trim().to_string()).collect();
+                    cells.resize(columns.len(), String::new());
+                    cells.truncate(columns.len());
+                    cells
+                })
+        })
+        .collect::<Result<_, _>>()?;
+
+    if rows.is_empty() {
+        return Err(ImportError::Empty);
+    }
+
+    Ok(ParsedFile { columns, rows })
+}
+
+fn detect_delimiter(bytes: &[u8]) -> u8 {
+    let first_line = bytes.split(|&b| b == b'\n').next().unwrap_or(bytes);
+    let tabs = first_line.iter().filter(|&&b| b == b'\t').count();
+    let commas = first_line.iter().filter(|&&b| b == b',').count();
+    if tabs > commas { b'\t' } else { b',' }
+}