nucleation 0.10.13

//! Per-build tiering. Pure: no cross-build comparison, so it shards trivially.
//! Every tier decision carries the signals that produced it, so a human can
//! see why. The machine orders the queue; it does not decide worth — `Debris`
//! is retained, never deleted.

use serde::{Deserialize, Serialize};

use crate::world_segment::ids::ClusterId;
use crate::world_segment::stitch::Build;

#[derive(Clone, Copy, PartialEq, Eq, Debug, Serialize, Deserialize)]
pub enum Tier {
    Confident,
    Probable,
    Debris,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
pub struct Signal {
    pub name: String,
    pub value: f64,
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
pub struct ScoreConfig {
    pub debris_max_blocks: u64,
    pub confident_min_blocks: u64,
    pub confident_min_density: f64,
}

impl Default for ScoreConfig {
    fn default() -> Self {
        ScoreConfig {
            debris_max_blocks: 100,
            confident_min_blocks: 1000,
            confident_min_density: 0.02,
        }
    }
}

#[derive(Clone, PartialEq, Debug, Serialize, Deserialize)]
pub struct Scored {
    pub build_id: ClusterId,
    pub tier: Tier,
    pub signals: Vec<Signal>,
}

fn volume(bbox: ((i32, i32, i32), (i32, i32, i32))) -> u64 {
    let dx = (bbox.1 .0 - bbox.0 .0 + 1).max(1) as u64;
    let dy = (bbox.1 .1 - bbox.0 .1 + 1).max(1) as u64;
    let dz = (bbox.1 .2 - bbox.0 .2 + 1).max(1) as u64;
    dx * dy * dz
}

pub fn score(build: &Build, cfg: &ScoreConfig) -> Scored {
    let vol = volume(build.bbox);
    let density = build.block_count as f64 / vol as f64;
    let signals = vec![
        Signal {
            name: "block_count".into(),
            value: build.block_count as f64,
        },
        Signal {
            name: "cell_count".into(),
            value: build.cell_count as f64,
        },
        Signal {
            name: "bbox_volume".into(),
            value: vol as f64,
        },
        Signal {
            name: "density".into(),
            value: density,
        },
        Signal {
            name: "cluster_count".into(),
            value: build.cluster_ids.len() as f64,
        },
    ];
    let tier = if build.block_count <= cfg.debris_max_blocks {
        Tier::Debris
    } else if build.block_count >= cfg.confident_min_blocks && density >= cfg.confident_min_density
    {
        Tier::Confident
    } else {
        Tier::Probable
    };
    Scored {
        build_id: build.id,
        tier,
        signals,
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::world_segment::ids::{ClusterId, ContentId, TileId};
    use crate::world_segment::stitch::Build;

    fn build(blocks: u64, bbox: ((i32, i32, i32), (i32, i32, i32))) -> Build {
        let id = ClusterId::new(
            ContentId::of(&[b"x"]),
            TileId { x: 0, z: 0 },
            None,
            (0, 0, 0),
        );
        Build {
            id,
            cluster_ids: vec![id],
            bbox,
            block_count: blocks,
            cell_count: blocks / 4 + 1,
            partition_id: None,
        }
    }

    fn cfg() -> ScoreConfig {
        ScoreConfig {
            debris_max_blocks: 20,
            confident_min_blocks: 500,
            confident_min_density: 0.05,
        }
    }

    #[test]
    fn tiny_clusters_are_debris() {
        let s = score(&build(5, ((0, 0, 0), (1, 1, 1))), &cfg());
        assert_eq!(s.tier, Tier::Debris);
    }

    #[test]
    fn large_dense_builds_are_confident() {
        // 1000 blocks in a 10x10x10 box (volume 1000) -> density 1.0.
        let s = score(&build(1000, ((0, 0, 0), (9, 9, 9))), &cfg());
        assert_eq!(s.tier, Tier::Confident);
    }

    #[test]
    fn large_but_sparse_builds_are_probable() {
        // 100 blocks spread across a 50x50x50 box -> density ~0.0008 < 0.05,
        // and 100 < confident_min_blocks -> Probable (above debris, below confident).
        let s = score(&build(100, ((0, 0, 0), (49, 49, 49))), &cfg());
        assert_eq!(s.tier, Tier::Probable);
    }

    #[test]
    fn signals_are_recorded_and_named() {
        let s = score(&build(1000, ((0, 0, 0), (9, 9, 9))), &cfg());
        assert!(s
            .signals
            .iter()
            .any(|sg| sg.name == "block_count" && sg.value == 1000.0));
        assert!(s
            .signals
            .iter()
            .any(|sg| sg.name == "density" && sg.value == 1.0));
    }

    #[test]
    fn score_config_round_trips_through_serde_json() {
        let c = cfg();
        let round_tripped: ScoreConfig =
            serde_json::from_str(&serde_json::to_string(&c).unwrap()).unwrap();
        assert_eq!(c, round_tripped);
    }
}