reifydb-routine 0.5.6

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

use reifydb_core::value::column::{ColumnWithName, buffer::ColumnBuffer, columns::Columns};
use reifydb_type::value::r#type::Type;

use crate::routine::{Function, FunctionKind, Routine, RoutineInfo, context::FunctionContext, error::RoutineError};

pub struct Lcm {
	info: RoutineInfo,
}

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

impl Lcm {
	pub fn new() -> Self {
		Self {
			info: RoutineInfo::new("math::lcm"),
		}
	}
}

fn numeric_to_i64(data: &ColumnBuffer, i: usize) -> Option<i64> {
	match data {
		ColumnBuffer::Int1(c) => c.get(i).map(|&v| v as i64),
		ColumnBuffer::Int2(c) => c.get(i).map(|&v| v as i64),
		ColumnBuffer::Int4(c) => c.get(i).map(|&v| v as i64),
		ColumnBuffer::Int8(c) => c.get(i).copied(),
		ColumnBuffer::Int16(c) => c.get(i).map(|&v| v as i64),
		ColumnBuffer::Uint1(c) => c.get(i).map(|&v| v as i64),
		ColumnBuffer::Uint2(c) => c.get(i).map(|&v| v as i64),
		ColumnBuffer::Uint4(c) => c.get(i).map(|&v| v as i64),
		ColumnBuffer::Uint8(c) => c.get(i).map(|&v| v as i64),
		_ => None,
	}
}

fn compute_gcd(mut a: i64, mut b: i64) -> i64 {
	a = a.abs();
	b = b.abs();
	while b != 0 {
		let t = b;
		b = a % b;
		a = t;
	}
	a
}

fn compute_lcm(a: i64, b: i64) -> i64 {
	if a == 0 || b == 0 {
		return 0;
	}
	(a.abs() / compute_gcd(a, b)) * b.abs()
}

impl<'a> Routine<FunctionContext<'a>> for Lcm {
	fn info(&self) -> &RoutineInfo {
		&self.info
	}

	fn return_type(&self, _input_types: &[Type]) -> Type {
		Type::Int8
	}

	fn execute(&self, ctx: &mut FunctionContext<'a>, args: &Columns) -> Result<Columns, RoutineError> {
		if args.len() != 2 {
			return Err(RoutineError::FunctionArityMismatch {
				function: ctx.fragment.clone(),
				expected: 2,
				actual: args.len(),
			});
		}

		let a_col = &args[0];
		let b_col = &args[1];

		let (a_data, a_bitvec) = a_col.unwrap_option();
		let (b_data, b_bitvec) = b_col.unwrap_option();
		let row_count = a_data.len();

		let expected_types = vec![
			Type::Int1,
			Type::Int2,
			Type::Int4,
			Type::Int8,
			Type::Uint1,
			Type::Uint2,
			Type::Uint4,
			Type::Uint8,
		];
		if !a_data.get_type().is_number() {
			return Err(RoutineError::FunctionInvalidArgumentType {
				function: ctx.fragment.clone(),
				argument_index: 0,
				expected: expected_types,
				actual: a_data.get_type(),
			});
		}
		if !b_data.get_type().is_number() {
			return Err(RoutineError::FunctionInvalidArgumentType {
				function: ctx.fragment.clone(),
				argument_index: 1,
				expected: expected_types,
				actual: b_data.get_type(),
			});
		}

		let mut result = Vec::with_capacity(row_count);
		let mut res_bitvec = Vec::with_capacity(row_count);

		for i in 0..row_count {
			match (numeric_to_i64(a_data, i), numeric_to_i64(b_data, i)) {
				(Some(a), Some(b)) => {
					result.push(compute_lcm(a, b));
					res_bitvec.push(true);
				}
				_ => {
					result.push(0);
					res_bitvec.push(false);
				}
			}
		}

		let result_data = ColumnBuffer::int8_with_bitvec(result, res_bitvec);
		let combined_bitvec = match (a_bitvec, b_bitvec) {
			(Some(a), Some(b)) => Some(a.and(b)),
			(Some(a), None) => Some(a.clone()),
			(None, Some(b)) => Some(b.clone()),
			(None, None) => None,
		};

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

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

impl Function for Lcm {
	fn kinds(&self) -> &[FunctionKind] {
		&[FunctionKind::Scalar]
	}
}