feat: Add support for tabular/csv data input.

crates/pikl-core/src/model/column.rs

@@ -0,0 +1,155 @@
+//! Column configuration for table mode. Defines which fields
+//! to display as columns and how to label them.
+
+use crate::item::resolve_field_path;
+use serde_json::Value;
+
+/// A single column definition: which field to extract and
+/// what to call it in the header.
+#[derive(Debug, Clone)]
+pub struct ColumnDef {
+    /// Dotted path into the item's JSON value (e.g. "meta.res").
+    pub field: String,
+    /// Display name for the column header. Defaults to the
+    /// field path if no alias is given.
+    pub display_name: String,
+}
+
+/// Column layout for table mode. Controls which fields are
+/// shown and in what order.
+#[derive(Debug, Clone)]
+pub struct ColumnConfig {
+    pub columns: Vec<ColumnDef>,
+}
+
+impl ColumnConfig {
+    /// Parse a column spec string like "label,meta.res:Resolution,meta.size".
+    /// Columns are comma-separated. Each column can have an alias
+    /// after the first colon: "field:Alias".
+    pub fn parse(spec: &str) -> Self {
+        let columns = spec
+            .split(',')
+            .filter(|s| !s.is_empty())
+            .map(|part| {
+                let part = part.trim();
+                if let Some((field, alias)) = part.split_once(':') {
+                    ColumnDef {
+                        field: field.trim().to_string(),
+                        display_name: alias.trim().to_string(),
+                    }
+                } else {
+                    ColumnDef {
+                        field: part.to_string(),
+                        display_name: part.to_string(),
+                    }
+                }
+            })
+            .collect();
+        Self { columns }
+    }
+
+    /// Build a ColumnConfig from raw header names. Used when
+    /// auto-generating columns from CSV headers.
+    pub fn from_headers(headers: &[String]) -> Self {
+        let columns = headers
+            .iter()
+            .map(|h| ColumnDef {
+                field: h.clone(),
+                display_name: h.clone(),
+            })
+            .collect();
+        Self { columns }
+    }
+
+    /// Resolve each column's value from an item's JSON value.
+    /// Missing fields produce an empty string.
+    pub fn resolve_values(&self, value: &Value) -> Vec<String> {
+        self.columns
+            .iter()
+            .map(|col| {
+                resolve_field_path(value, &col.field)
+                    .map(value_to_cell)
+                    .unwrap_or_default()
+            })
+            .collect()
+    }
+}
+
+/// Convert a JSON value to a cell string for display.
+fn value_to_cell(v: &Value) -> String {
+    match v {
+        Value::String(s) => s.clone(),
+        Value::Number(n) => n.to_string(),
+        Value::Bool(b) => b.to_string(),
+        Value::Null => String::new(),
+        other => other.to_string(),
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use serde_json::json;
+
+    #[test]
+    fn parse_simple_columns() {
+        let config = ColumnConfig::parse("label,age,city");
+        assert_eq!(config.columns.len(), 3);
+        assert_eq!(config.columns[0].field, "label");
+        assert_eq!(config.columns[0].display_name, "label");
+        assert_eq!(config.columns[2].field, "city");
+    }
+
+    #[test]
+    fn parse_with_alias() {
+        let config = ColumnConfig::parse("label,meta.res:Resolution");
+        assert_eq!(config.columns.len(), 2);
+        assert_eq!(config.columns[1].field, "meta.res");
+        assert_eq!(config.columns[1].display_name, "Resolution");
+    }
+
+    #[test]
+    fn parse_empty_string() {
+        let config = ColumnConfig::parse("");
+        assert!(config.columns.is_empty());
+    }
+
+    #[test]
+    fn parse_trailing_comma() {
+        let config = ColumnConfig::parse("label,age,");
+        assert_eq!(config.columns.len(), 2);
+    }
+
+    #[test]
+    fn resolve_flat_values() {
+        let config = ColumnConfig::parse("label,age");
+        let value = json!({"label": "alice", "age": 30});
+        let cells = config.resolve_values(&value);
+        assert_eq!(cells, vec!["alice", "30"]);
+    }
+
+    #[test]
+    fn resolve_nested_values() {
+        let config = ColumnConfig::parse("label,meta.res");
+        let value = json!({"label": "test", "meta": {"res": "1080p"}});
+        let cells = config.resolve_values(&value);
+        assert_eq!(cells, vec!["test", "1080p"]);
+    }
+
+    #[test]
+    fn resolve_missing_field() {
+        let config = ColumnConfig::parse("label,nope");
+        let value = json!({"label": "test"});
+        let cells = config.resolve_values(&value);
+        assert_eq!(cells, vec!["test", ""]);
+    }
+
+    #[test]
+    fn from_headers_builds_identity() {
+        let headers = vec!["name".to_string(), "age".to_string()];
+        let config = ColumnConfig::from_headers(&headers);
+        assert_eq!(config.columns.len(), 2);
+        assert_eq!(config.columns[0].field, "name");
+        assert_eq!(config.columns[0].display_name, "name");
+    }
+}