// Copyright 2026 Zhanbo Li / Atlas Lee <zhanbo.lee@hotmail.com>
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.


/// Queryplan
#[derive(Debug, Clone)]
pub struct QueryPlan {
    pub steps: Vec<PlanStep>,
}

/// plan step
#[derive(Debug, Clone)]
pub enum PlanStep {
    Scan { def: String, filter: Option<String> },
    Filter { predicate: String },
    Project { fields: Vec<String> },
    Aggregate { op: String, field: String },
    Limit { n: usize },
}

impl QueryPlan {
    pub fn new() -> Self {
        Self { steps: Vec::new() }
    }

    pub fn add_step(&mut self, step: PlanStep) {
        self.steps.push(step);
    }
}

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