reifydb-routine 0.4.11

// SPDX-License-Identifier: Apache-2.0
// Copyright (c) 2025 ReifyDB

use reifydb_core::value::column::{Column, columns::Columns, data::ColumnData};
use reifydb_type::value::r#type::Type;

use crate::function::{Function, FunctionCapability, FunctionContext, FunctionInfo, error::FunctionError};

pub struct DateTimeMonth {
	info: FunctionInfo,
}

impl Default for DateTimeMonth {
	fn default() -> Self {
		Self::new()
	}
}

impl DateTimeMonth {
	pub fn new() -> Self {
		Self {
			info: FunctionInfo::new("datetime::month"),
		}
	}
}

impl Function for DateTimeMonth {
	fn info(&self) -> &FunctionInfo {
		&self.info
	}

	fn capabilities(&self) -> &[FunctionCapability] {
		&[FunctionCapability::Scalar]
	}

	fn return_type(&self, _input_types: &[Type]) -> Type {
		Type::Int4
	}

	fn execute(&self, ctx: &FunctionContext, args: &Columns) -> Result<Columns, FunctionError> {
		if args.len() != 1 {
			return Err(FunctionError::ArityMismatch {
				function: ctx.fragment.clone(),
				expected: 1,
				actual: args.len(),
			});
		}

		let column = &args[0];
		let (data, bitvec) = column.data().unwrap_option();
		let row_count = data.len();

		let result_data = match data {
			ColumnData::DateTime(container) => {
				let mut result = Vec::with_capacity(row_count);
				let mut res_bitvec = Vec::with_capacity(row_count);

				for i in 0..row_count {
					if let Some(dt) = container.get(i) {
						result.push(dt.month() as i32);
						res_bitvec.push(true);
					} else {
						result.push(0);
						res_bitvec.push(false);
					}
				}

				ColumnData::int4_with_bitvec(result, res_bitvec)
			}
			other => {
				return Err(FunctionError::InvalidArgumentType {
					function: ctx.fragment.clone(),
					argument_index: 0,
					expected: vec![Type::DateTime],
					actual: other.get_type(),
				});
			}
		};

		let final_data = if let Some(bv) = bitvec {
			ColumnData::Option {
				inner: Box::new(result_data),
				bitvec: bv.clone(),
			}
		} else {
			result_data
		};

		Ok(Columns::new(vec![Column::new(ctx.fragment.clone(), final_data)]))
	}
}