nornir 0.4.53

//! Iceberg writer + reader for the **reversible release-change ledger**
//! (`release_changes`, task #32).
//!
//! Every MUTATING step of a release run records one [`ReleaseChange`] row WITH
//! the before-state needed to reverse it: a version bump carries the exact
//! pre-bump manifest text; a patch-strip carries the removed `[patch]` block; a
//! branch cut carries the SHA HEAD was at; a publish carries whether it landed on
//! an immutable registry (crates.io → can only be yanked, never un-published).
//!
//! A `release_id` groups one run's records. [`record_change`] appends one row
//! (best-effort, but here it IS the safety net so callers should surface a write
//! error). [`query_release_changes`] reads a run's rows; `nornir release undo`
//! reverses them newest-first (`seq` descending).
//!
//! Schema: [`super::iceberg_schema::release_changes`].

use std::sync::Arc;
use std::sync::atomic::{AtomicI64, Ordering};

use anyhow::{anyhow, Result};
use arrow::array::{
    Array, BooleanArray, Int64Array, RecordBatch, StringArray, TimestampMicrosecondArray,
};
use iceberg::Catalog;
use iceberg::arrow::schema_to_arrow_schema;
use sha2::{Digest, Sha256};
use uuid::Uuid;

use super::iceberg::{IcebergWarehouse, TABLE_RELEASE_CHANGES, append_batch};

// Column indices match `iceberg_schema::release_changes` field order.
const COL_RELEASE_ID: usize = 0;
const COL_SEQ: usize = 1;
const COL_TS_MICROS: usize = 2;
const COL_KIND: usize = 3;
const COL_REPO: usize = 4;
const COL_CHANGE_SHA: usize = 5;
const COL_CRATE_NAME: usize = 6;
const COL_OLD_VERSION: usize = 7;
const COL_NEW_VERSION: usize = 8;
const COL_FILE: usize = 9;
const COL_OLD_REQ_LINES: usize = 10;
const COL_REMOVED_BLOCK: usize = 11;
const COL_BRANCH: usize = 12;
const COL_PREV_HEAD: usize = 13;
const COL_REGISTRY: usize = 14;
const COL_IMMUTABLE: usize = 15;

/// Canonical `kind` tags.
pub mod kind {
    pub const BUMP: &str = "bump";
    pub const PATCH_STRIP: &str = "patch_strip";
    pub const BRANCH: &str = "branch";
    pub const PUBLISH: &str = "publish";
}

/// The reversible payload of one mutating release step. Only the fields relevant
/// to a `kind` are populated; the rest are `None`.
#[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
pub enum ChangeKind {
    /// A coordinated version bump in one manifest. `old_file_text` is the WHOLE
    /// pre-bump manifest so undo restores it byte-for-byte.
    Bump {
        crate_name: String,
        old_version: String,
        new_version: String,
        file: String,
        old_file_text: String,
    },
    /// A `[patch.crates-io]` strip from one manifest. `removed_block` is the
    /// stripped text (the lost lines) — undo re-appends it.
    PatchStrip { file: String, removed_block: String },
    /// A release-branch cut. `prev_head` is the SHA HEAD pointed at before (empty
    /// when the branch was freshly created → undo deletes it).
    Branch { repo: String, branch: String, prev_head: String },
    /// A publish. `immutable` is true for crates.io (undo → yank, never
    /// un-publish); false for a /sparring rehearsal.
    Publish { crate_name: String, version: String, registry: String, immutable: bool },
}

/// One row of the `release_changes` ledger.
#[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
pub struct ReleaseChange {
    /// The release run these records group under.
    pub release_id: String,
    /// Per-run monotonic sequence — the durable ordering key (undo reverses by
    /// `seq` descending).
    pub seq: i64,
    /// Event time, microseconds since the Unix epoch (UTC).
    pub ts_micros: i64,
    /// The repo this change touched (the workspace member / checkout name).
    pub repo: String,
    /// sha256 of the canonical payload (integrity + dedup).
    pub change_sha: String,
    /// The reversible payload.
    pub change: ChangeKind,
}

impl ReleaseChange {
    /// `(release_id, seq)` sort key.
    fn key(&self) -> (String, i64) {
        (self.release_id.clone(), self.seq)
    }
}

/// Mints monotonic `seq` for one release run's change records.
#[derive(Clone)]
pub struct ChangeRecorder {
    release_id: String,
    seq: Arc<AtomicI64>,
}

impl ChangeRecorder {
    pub fn new(release_id: impl Into<String>) -> Self {
        Self { release_id: release_id.into(), seq: Arc::new(AtomicI64::new(0)) }
    }

    pub fn release_id(&self) -> &str {
        &self.release_id
    }

    /// Build the next [`ReleaseChange`] (stamped now, fresh `seq`, computed
    /// `change_sha`) WITHOUT writing it.
    pub fn build(&self, repo: &str, change: ChangeKind) -> ReleaseChange {
        let seq = self.seq.fetch_add(1, Ordering::SeqCst);
        let change_sha = change_sha(&change);
        ReleaseChange {
            release_id: self.release_id.clone(),
            seq,
            ts_micros: chrono::Utc::now().timestamp_micros(),
            repo: repo.to_string(),
            change_sha,
            change,
        }
    }

    /// Build + append one change record to the warehouse.
    pub fn record(&self, wh: &IcebergWarehouse, repo: &str, change: ChangeKind) -> Result<()> {
        let row = self.build(repo, change);
        wh.block_on(append_release_changes(wh, std::slice::from_ref(&row)))
    }
}

/// sha256 of a change's canonical payload — `kind|field|field|…`.
fn change_sha(change: &ChangeKind) -> String {
    let mut h = Sha256::new();
    match change {
        ChangeKind::Bump { crate_name, old_version, new_version, file, old_file_text } => {
            h.update(b"bump\0");
            for p in [crate_name, old_version, new_version, file, old_file_text] {
                h.update(p.as_bytes());
                h.update(b"\0");
            }
        }
        ChangeKind::PatchStrip { file, removed_block } => {
            h.update(b"patch_strip\0");
            h.update(file.as_bytes());
            h.update(b"\0");
            h.update(removed_block.as_bytes());
        }
        ChangeKind::Branch { repo, branch, prev_head } => {
            h.update(b"branch\0");
            for p in [repo, branch, prev_head] {
                h.update(p.as_bytes());
                h.update(b"\0");
            }
        }
        ChangeKind::Publish { crate_name, version, registry, immutable } => {
            h.update(b"publish\0");
            for p in [crate_name, version, registry] {
                h.update(p.as_bytes());
                h.update(b"\0");
            }
            h.update(if *immutable { b"1" } else { b"0" });
        }
    }
    format!("{:x}", h.finalize())
}

/// Append change records (one Iceberg snapshot).
pub async fn append_release_changes(wh: &IcebergWarehouse, rows: &[ReleaseChange]) -> Result<()> {
    if rows.is_empty() {
        return Ok(());
    }
    let table = wh.catalog().load_table(&wh.table_ident(TABLE_RELEASE_CHANGES)).await?;
    let arrow_schema = Arc::new(schema_to_arrow_schema(table.metadata().current_schema())?);

    // Project each row's optional fields by kind.
    let kind_of = |c: &ChangeKind| match c {
        ChangeKind::Bump { .. } => kind::BUMP,
        ChangeKind::PatchStrip { .. } => kind::PATCH_STRIP,
        ChangeKind::Branch { .. } => kind::BRANCH,
        ChangeKind::Publish { .. } => kind::PUBLISH,
    };
    let crate_name = |c: &ChangeKind| match c {
        ChangeKind::Bump { crate_name, .. } | ChangeKind::Publish { crate_name, .. } => {
            Some(crate_name.clone())
        }
        _ => None,
    };
    let old_version = |c: &ChangeKind| match c {
        ChangeKind::Bump { old_version, .. } => Some(old_version.clone()),
        _ => None,
    };
    let new_version = |c: &ChangeKind| match c {
        ChangeKind::Bump { new_version, .. } => Some(new_version.clone()),
        ChangeKind::Publish { version, .. } => Some(version.clone()),
        _ => None,
    };
    let file = |c: &ChangeKind| match c {
        ChangeKind::Bump { file, .. } | ChangeKind::PatchStrip { file, .. } => Some(file.clone()),
        _ => None,
    };
    let old_req_lines = |c: &ChangeKind| match c {
        ChangeKind::Bump { old_file_text, .. } => Some(old_file_text.clone()),
        _ => None,
    };
    let removed_block = |c: &ChangeKind| match c {
        ChangeKind::PatchStrip { removed_block, .. } => Some(removed_block.clone()),
        _ => None,
    };
    let branch = |c: &ChangeKind| match c {
        ChangeKind::Branch { branch, .. } => Some(branch.clone()),
        _ => None,
    };
    let prev_head = |c: &ChangeKind| match c {
        ChangeKind::Branch { prev_head, .. } => Some(prev_head.clone()),
        _ => None,
    };
    let registry = |c: &ChangeKind| match c {
        ChangeKind::Publish { registry, .. } => Some(registry.clone()),
        _ => None,
    };
    let immutable = |c: &ChangeKind| match c {
        ChangeKind::Publish { immutable, .. } => Some(*immutable),
        _ => None,
    };

    let cols: Vec<Arc<dyn Array>> = vec![
        Arc::new(StringArray::from(rows.iter().map(|r| r.release_id.clone()).collect::<Vec<_>>())),
        Arc::new(Int64Array::from(rows.iter().map(|r| r.seq).collect::<Vec<_>>())),
        Arc::new(
            TimestampMicrosecondArray::from(rows.iter().map(|r| r.ts_micros).collect::<Vec<_>>())
                .with_timezone("+00:00"),
        ),
        Arc::new(StringArray::from(rows.iter().map(|r| kind_of(&r.change).to_string()).collect::<Vec<_>>())),
        Arc::new(StringArray::from(rows.iter().map(|r| r.repo.clone()).collect::<Vec<_>>())),
        Arc::new(StringArray::from(rows.iter().map(|r| r.change_sha.clone()).collect::<Vec<_>>())),
        Arc::new(StringArray::from(rows.iter().map(|r| crate_name(&r.change)).collect::<Vec<_>>())),
        Arc::new(StringArray::from(rows.iter().map(|r| old_version(&r.change)).collect::<Vec<_>>())),
        Arc::new(StringArray::from(rows.iter().map(|r| new_version(&r.change)).collect::<Vec<_>>())),
        Arc::new(StringArray::from(rows.iter().map(|r| file(&r.change)).collect::<Vec<_>>())),
        Arc::new(StringArray::from(rows.iter().map(|r| old_req_lines(&r.change)).collect::<Vec<_>>())),
        Arc::new(StringArray::from(rows.iter().map(|r| removed_block(&r.change)).collect::<Vec<_>>())),
        Arc::new(StringArray::from(rows.iter().map(|r| branch(&r.change)).collect::<Vec<_>>())),
        Arc::new(StringArray::from(rows.iter().map(|r| prev_head(&r.change)).collect::<Vec<_>>())),
        Arc::new(StringArray::from(rows.iter().map(|r| registry(&r.change)).collect::<Vec<_>>())),
        Arc::new(BooleanArray::from(rows.iter().map(|r| immutable(&r.change)).collect::<Vec<_>>())),
    ];
    let batch = RecordBatch::try_new(arrow_schema, cols)?;
    append_batch(wh.catalog(), table, batch).await?;
    Ok(())
}

/// Read every change record for `release_id`, sorted by `(release_id, seq)`.
/// Pass `None` to read every run, then pick the most recent by max `ts_micros`.
pub async fn query_release_changes(
    wh: &IcebergWarehouse,
    release_id: Option<&str>,
) -> Result<Vec<ReleaseChange>> {
    let table = wh.catalog().load_table(&wh.table_ident(TABLE_RELEASE_CHANGES)).await?;
    let batches: Vec<RecordBatch> = skade::read_all(&table).await?;

    let mut out: Vec<ReleaseChange> = Vec::new();
    for b in &batches {
        let rid = col_str(b, COL_RELEASE_ID)?;
        let seq = col_i64(b, COL_SEQ)?;
        let ts = col_ts(b, COL_TS_MICROS)?;
        let kind = col_str(b, COL_KIND)?;
        let repo = col_str(b, COL_REPO)?;
        let sha = col_str(b, COL_CHANGE_SHA)?;
        let crate_name = col_str(b, COL_CRATE_NAME)?;
        let old_version = col_str(b, COL_OLD_VERSION)?;
        let new_version = col_str(b, COL_NEW_VERSION)?;
        let file = col_str(b, COL_FILE)?;
        let old_req = col_str(b, COL_OLD_REQ_LINES)?;
        let removed = col_str(b, COL_REMOVED_BLOCK)?;
        let branch = col_str(b, COL_BRANCH)?;
        let prev_head = col_str(b, COL_PREV_HEAD)?;
        let registry = col_str(b, COL_REGISTRY)?;
        let immutable = col_bool(b, COL_IMMUTABLE)?;
        let s = |a: &StringArray, i: usize| if a.is_null(i) { String::new() } else { a.value(i).to_string() };
        for i in 0..b.num_rows() {
            let change = match kind.value(i) {
                kind::BUMP => ChangeKind::Bump {
                    crate_name: s(crate_name, i),
                    old_version: s(old_version, i),
                    new_version: s(new_version, i),
                    file: s(file, i),
                    old_file_text: s(old_req, i),
                },
                kind::PATCH_STRIP => ChangeKind::PatchStrip {
                    file: s(file, i),
                    removed_block: s(removed, i),
                },
                kind::BRANCH => ChangeKind::Branch {
                    repo: s(repo, i),
                    branch: s(branch, i),
                    prev_head: s(prev_head, i),
                },
                kind::PUBLISH => ChangeKind::Publish {
                    crate_name: s(crate_name, i),
                    version: s(new_version, i),
                    registry: s(registry, i),
                    immutable: !immutable.is_null(i) && immutable.value(i),
                },
                other => return Err(anyhow!("unknown release_change kind `{other}`")),
            };
            let row = ReleaseChange {
                release_id: rid.value(i).to_string(),
                seq: seq.value(i),
                ts_micros: ts.value(i),
                repo: repo.value(i).to_string(),
                change_sha: sha.value(i).to_string(),
                change,
            };
            if release_id.map(|id| row.release_id == id).unwrap_or(true) {
                out.push(row);
            }
        }
    }
    out.sort_by_key(|r| r.key());
    Ok(out)
}

/// The `release_id` of the most recent run in the ledger (max `ts_micros`), or
/// `None` if the ledger is empty.
pub async fn latest_release_id(wh: &IcebergWarehouse) -> Result<Option<String>> {
    let all = query_release_changes(wh, None).await?;
    Ok(all.iter().max_by_key(|r| r.ts_micros).map(|r| r.release_id.clone()))
}

/// A fresh release id (UUIDv4).
pub fn new_release_id() -> String {
    Uuid::new_v4().to_string()
}

// ─── column helpers ─────────────────────────────────────────────────────

fn col_str<'a>(b: &'a RecordBatch, idx: usize) -> Result<&'a StringArray> {
    b.column(idx)
        .as_any()
        .downcast_ref::<StringArray>()
        .ok_or_else(|| anyhow!("release_changes col {idx} is not StringArray"))
}

fn col_i64<'a>(b: &'a RecordBatch, idx: usize) -> Result<&'a Int64Array> {
    b.column(idx)
        .as_any()
        .downcast_ref::<Int64Array>()
        .ok_or_else(|| anyhow!("release_changes col {idx} is not Int64Array"))
}

fn col_ts<'a>(b: &'a RecordBatch, idx: usize) -> Result<&'a TimestampMicrosecondArray> {
    b.column(idx)
        .as_any()
        .downcast_ref::<TimestampMicrosecondArray>()
        .ok_or_else(|| anyhow!("release_changes col {idx} is not TimestampMicrosecondArray"))
}

fn col_bool<'a>(b: &'a RecordBatch, idx: usize) -> Result<&'a BooleanArray> {
    b.column(idx)
        .as_any()
        .downcast_ref::<BooleanArray>()
        .ok_or_else(|| anyhow!("release_changes col {idx} is not BooleanArray"))
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn append_and_query_round_trips_each_kind() {
        let dir = tempfile::tempdir().unwrap();
        let wh = IcebergWarehouse::open(dir.path()).unwrap();
        let rec = ChangeRecorder::new("run-xyz");

        let bump = rec.build("skade", ChangeKind::Bump {
            crate_name: "arrow".into(),
            old_version: "57".into(),
            new_version: "58".into(),
            file: "Cargo.toml".into(),
            old_file_text: "[dependencies]\narrow = \"57\"\n".into(),
        });
        let strip = rec.build("nornir", ChangeKind::PatchStrip {
            file: "Cargo.toml".into(),
            removed_block: "[patch.crates-io]\niceberg = { path = \"../fork\" }\n".into(),
        });
        let branch = rec.build("nornir", ChangeKind::Branch {
            repo: "nornir".into(),
            branch: "release/staging".into(),
            prev_head: "deadbeef".into(),
        });
        let publish = rec.build("nornir", ChangeKind::Publish {
            crate_name: "nornir".into(),
            version: "0.2.0".into(),
            registry: "crates.io".into(),
            immutable: true,
        });
        wh.block_on(append_release_changes(&wh, &[bump.clone(), strip.clone(), branch.clone(), publish.clone()]))
            .unwrap();

        let rows = wh.block_on(query_release_changes(&wh, Some("run-xyz"))).unwrap();
        assert_eq!(rows.len(), 4);
        assert_eq!(rows.iter().map(|r| r.seq).collect::<Vec<_>>(), vec![0, 1, 2, 3]);
        assert_eq!(rows[0].change, bump.change);
        assert_eq!(rows[1].change, strip.change);
        assert_eq!(rows[2].change, branch.change);
        assert_eq!(rows[3].change, publish.change);
        // change_sha is stable + non-empty.
        assert!(!rows[0].change_sha.is_empty());
        assert_eq!(rows[0].change_sha, change_sha(&bump.change));

        // Latest-run resolution.
        let latest = wh.block_on(latest_release_id(&wh)).unwrap();
        assert_eq!(latest.as_deref(), Some("run-xyz"));
    }
}