nornir 0.4.54

//! `nornir release undo` (task #32) — reverse a release run's mutating steps.
//!
//! Every mutating release step records a [`ReleaseChange`] with its BEFORE-STATE
//! into the `release_changes` ledger (see [`crate::warehouse::release_changes`]).
//! This module owns:
//!
//!  * the RECORD wrappers — capture the before-state, apply the mutation, append
//!    the ledger row. The release path calls these instead of the bare
//!    `cargo`/`publish` engines so a run is reversible:
//!      - [`record_bump`]       wraps `apply_bump_plan`
//!      - [`record_skew_bumps`] wraps `apply_skew_bumps`
//!      - [`record_patch_strip`]wraps `strip_patch_crates_io`
//!      - [`record_branch`]     records a branch cut (capturing prev HEAD)
//!      - [`record_publish`]    records a publish (immutable = crates.io)
//!
//!  * the UNDO engine — read a run's records newest-first and reverse each:
//!    un-bump (restore the exact pre-bump manifest text), restore the stripped
//!    `[patch]` block, delete/restore the branch (back to `prev_head`); a
//!    crates.io `publish` can't be un-published, so it is YANKED and reported.
//!
//! Rides on the existing time-travel + `guard`/revert ethos: the ledger is the
//! durable, SHA-keyed source of truth, so undo works even across a fresh process.

use std::collections::BTreeMap;
use std::path::{Path, PathBuf};
use std::process::Command;

use anyhow::{Context, Result};

use crate::release::cargo::{
    apply_bump_plan, apply_skew_bumps, AppliedBump, VersionBumpPlan,
};
use crate::warehouse::iceberg::IcebergWarehouse;
use crate::warehouse::release_changes::{
    self, ChangeKind, ChangeRecorder, ReleaseChange,
};

// ─────────────────────── record wrappers ───────────────────────

/// Apply a version-bump plan, recording one reversible `Bump` row per touched
/// manifest WITH the exact pre-bump file text (so undo restores it byte-for-byte).
/// Returns the count of files modified (same as [`apply_bump_plan`]).
///
/// The before-text is captured per-file BEFORE the apply; the plan's `pkg` /
/// `old_version` / `new_version` describe the logical change. One record per file
/// is enough to fully reverse the bump (the whole manifest is restored).
pub fn record_bump(
    wh: &IcebergWarehouse,
    rec: &ChangeRecorder,
    repo: &str,
    plan: &VersionBumpPlan,
) -> Result<usize> {
    // Capture the before-text of every file the plan touches.
    let mut files: BTreeMap<PathBuf, String> = BTreeMap::new();
    for e in &plan.edits {
        if let std::collections::btree_map::Entry::Vacant(slot) =
            files.entry(e.cargo_toml.clone())
        {
            let text = std::fs::read_to_string(&e.cargo_toml)
                .with_context(|| format!("read before-state {}", e.cargo_toml.display()))?;
            slot.insert(text);
        }
    }
    // Apply.
    let n = apply_bump_plan(plan)?;
    // Record one row per file (carrying a representative crate/version from that
    // file's edits + the full before-text).
    for (path, before) in &files {
        let edit = plan.edits.iter().find(|e| &e.cargo_toml == path);
        let (crate_name, old_v, new_v) = edit
            .map(|e| (e.pkg.clone(), e.old_version.clone(), e.new_version.clone()))
            .unwrap_or_default();
        rec.record(
            wh,
            repo,
            ChangeKind::Bump {
                crate_name,
                old_version: old_v,
                new_version: new_v,
                file: path.to_string_lossy().into_owned(),
                old_file_text: before.clone(),
            },
        )?;
    }
    Ok(n)
}

/// Apply the doctor's skew bumps, recording a reversible `Bump` row per touched
/// manifest. Reuses [`apply_skew_bumps`] under the hood but captures before-state
/// per (repo, crate) plan so undo can restore each file.
pub fn record_skew_bumps(
    wh: &IcebergWarehouse,
    rec: &ChangeRecorder,
    skew: &[crate::release::doctor::CrateSkew],
    repo_paths: &BTreeMap<String, PathBuf>,
) -> Result<Vec<AppliedBump>> {
    // Re-plan per (repo, crate) so we can capture before-text; mirror the loop in
    // `apply_skew_bumps` but route each plan through `record_bump`.
    let mut applied = Vec::new();
    for c in skew {
        for repo in c.bump_repos() {
            let Some(root) = repo_paths.get(repo) else { continue };
            let plan = crate::release::cargo::plan_version_bump(root, &c.crate_name, &c.target, false)
                .with_context(|| format!("plan bump {} → {} in {repo}", c.crate_name, c.target))?;
            if plan.edits.is_empty() {
                continue;
            }
            let files = record_bump(wh, rec, repo, &plan)
                .with_context(|| format!("apply+record bump {} → {} in {repo}", c.crate_name, c.target))?;
            applied.push(AppliedBump {
                repo: repo.to_string(),
                crate_name: c.crate_name.clone(),
                target: c.target.clone(),
                files,
            });
        }
    }
    Ok(applied)
}

/// Record an ALREADY-APPLIED version bump for undo — captures the pre-bump file text
/// directly, WITHOUT re-applying a plan. Used by the unified-workspace bump
/// ([`crate::release::cargo::bump_workspace_version`]), whose edit (the virtual root's
/// `[workspace.package].version`) the generic plan-replay path can't reconstruct (no
/// `[package].version`). `edits` is `(manifest, before_text)`.
pub fn record_applied_bump(
    wh: &IcebergWarehouse,
    rec: &ChangeRecorder,
    repo: &str,
    crate_name: &str,
    old_version: &str,
    new_version: &str,
    edits: &[(PathBuf, String)],
) -> Result<()> {
    for (path, before) in edits {
        rec.record(
            wh,
            repo,
            ChangeKind::Bump {
                crate_name: crate_name.to_string(),
                old_version: old_version.to_string(),
                new_version: new_version.to_string(),
                file: path.to_string_lossy().into_owned(),
                old_file_text: before.clone(),
            },
        )?;
    }
    Ok(())
}

/// Strip the `[patch.crates-io]` block(s) from one manifest, recording the removed
/// text so undo can re-append it. Returns the number of blocks stripped. Captures
/// the before-text, computes the diff (the lost lines) as `removed_block`.
pub fn record_patch_strip(
    wh: &IcebergWarehouse,
    rec: &ChangeRecorder,
    repo: &str,
    cargo_toml: &Path,
) -> Result<usize> {
    let before = std::fs::read_to_string(cargo_toml)
        .with_context(|| format!("read before-state {}", cargo_toml.display()))?;
    let n = crate::release::cargo::strip_patch_crates_io(cargo_toml)?;
    if n == 0 {
        return Ok(0);
    }
    let after = std::fs::read_to_string(cargo_toml).unwrap_or_default();
    // The removed block = the lines present in `before` but not in `after`. A
    // strip only ever removes lines (formatting outside the block is preserved),
    // so the suffix-difference is exactly the patch text we must restore. We store
    // the WHOLE before-text under `removed_block` so undo is a verbatim restore —
    // simplest and guaranteed byte-correct.
    let _ = after;
    rec.record(
        wh,
        repo,
        ChangeKind::PatchStrip {
            file: cargo_toml.to_string_lossy().into_owned(),
            removed_block: before,
        },
    )?;
    Ok(n)
}

/// Record a release-branch cut (the branch is created by the caller). `prev_head`
/// is the SHA HEAD pointed at before the cut (empty when the branch is brand new
/// → undo deletes it; otherwise undo resets it back).
pub fn record_branch(
    wh: &IcebergWarehouse,
    rec: &ChangeRecorder,
    repo: &str,
    branch: &str,
    prev_head: &str,
) -> Result<()> {
    rec.record(
        wh,
        repo,
        ChangeKind::Branch {
            repo: repo.to_string(),
            branch: branch.to_string(),
            prev_head: prev_head.to_string(),
        },
    )
}

/// Record a publish. `immutable` must be true for crates.io (undo → yank, never
/// un-publish) and false for a /sparring rehearsal (a no-op to undo).
pub fn record_publish(
    wh: &IcebergWarehouse,
    rec: &ChangeRecorder,
    repo: &str,
    crate_name: &str,
    version: &str,
    registry: &str,
    immutable: bool,
) -> Result<()> {
    rec.record(
        wh,
        repo,
        ChangeKind::Publish {
            crate_name: crate_name.to_string(),
            version: version.to_string(),
            registry: registry.to_string(),
            immutable,
        },
    )
}

// ─────────────────────── undo engine ───────────────────────

/// One reversed step, for the report.
#[derive(Debug, Clone)]
pub struct UndoStep {
    pub seq: i64,
    pub kind: String,
    /// What undo did, human-readable.
    pub action: String,
    /// `true` when undo could not fully reverse it (e.g. an immutable publish →
    /// yanked instead).
    pub partial: bool,
}

/// Reverse `release_id`'s records newest-first. `repo_paths` maps a record's
/// `repo` to its on-disk checkout (for the file/branch operations); records whose
/// repo isn't on disk are skipped with a note. `dry_run` reports without acting.
/// `yank` actually runs `cargo yank` for immutable publishes (off → report only).
///
/// Pass `None` for `release_id` to undo the most recent run in the ledger.
pub fn undo_release(
    wh: &IcebergWarehouse,
    release_id: Option<&str>,
    repo_paths: &BTreeMap<String, PathBuf>,
    dry_run: bool,
    yank: bool,
) -> Result<Vec<UndoStep>> {
    let id = match release_id {
        Some(id) => id.to_string(),
        None => wh
            .block_on(release_changes::latest_release_id(wh))?
            .context("release undo: the release_changes ledger is empty (nothing to undo)")?,
    };
    let mut records: Vec<ReleaseChange> =
        wh.block_on(release_changes::query_release_changes(wh, Some(&id)))?;
    if records.is_empty() {
        anyhow::bail!("release undo: no records for release id `{id}`");
    }
    // Reverse newest-first.
    records.sort_by_key(|r| std::cmp::Reverse(r.seq));

    let mut steps = Vec::new();
    for r in &records {
        let step = reverse_one(r, repo_paths, dry_run, yank)?;
        steps.push(step);
    }
    Ok(steps)
}

fn reverse_one(
    r: &ReleaseChange,
    repo_paths: &BTreeMap<String, PathBuf>,
    dry_run: bool,
    yank: bool,
) -> Result<UndoStep> {
    match &r.change {
        ChangeKind::Bump { file, old_file_text, crate_name, new_version, old_version } => {
            let action = format!(
                "un-bump {crate_name} {new_version}→{old_version} (restore {file})"
            );
            if !dry_run {
                std::fs::write(file, old_file_text)
                    .with_context(|| format!("restore {file}"))?;
            }
            Ok(UndoStep { seq: r.seq, kind: "bump".into(), action, partial: false })
        }
        ChangeKind::PatchStrip { file, removed_block } => {
            let action = format!("restore [patch.crates-io] in {file}");
            if !dry_run {
                // We stored the whole before-text → a verbatim restore.
                std::fs::write(file, removed_block)
                    .with_context(|| format!("restore patch in {file}"))?;
            }
            Ok(UndoStep { seq: r.seq, kind: "patch_strip".into(), action, partial: false })
        }
        ChangeKind::Branch { repo, branch, prev_head } => {
            let path = repo_paths.get(repo);
            let action = if prev_head.is_empty() {
                format!("delete branch {branch} in {repo} (was freshly created)")
            } else {
                format!("reset branch {branch} in {repo} → {prev_head}")
            };
            if !dry_run {
                if let Some(p) = path {
                    if prev_head.is_empty() {
                        // Delete the branch (best-effort; ignore if checked out).
                        let _ = Command::new("git").arg("-C").arg(p)
                            .args(["branch", "-D", branch]).status();
                    } else {
                        let _ = Command::new("git").arg("-C").arg(p)
                            .args(["update-ref", &format!("refs/heads/{branch}"), prev_head])
                            .status();
                    }
                }
            }
            Ok(UndoStep { seq: r.seq, kind: "branch".into(), action, partial: path.is_none() })
        }
        ChangeKind::Publish { crate_name, version, registry, immutable } => {
            if *immutable {
                // crates.io is immutable — can't un-publish. Yank instead.
                let action = format!(
                    "YANK {crate_name}@{version} from {registry} (immutable — cannot un-publish)"
                );
                if !dry_run && yank {
                    let out = Command::new("cargo")
                        .args(["yank", "--version", version, crate_name])
                        .output()
                        .context("spawn cargo yank")?;
                    if !out.status.success() {
                        let stderr = String::from_utf8_lossy(&out.stderr);
                        // Already-yanked is fine.
                        if !stderr.contains("already yanked") {
                            anyhow::bail!("cargo yank {crate_name}@{version} failed: {stderr}");
                        }
                    }
                }
                Ok(UndoStep { seq: r.seq, kind: "publish".into(), action, partial: true })
            } else {
                // A /sparring rehearsal publish is ephemeral — nothing to reverse.
                Ok(UndoStep {
                    seq: r.seq,
                    kind: "publish".into(),
                    action: format!("{crate_name}@{version} was a {registry} rehearsal (no-op)"),
                    partial: false,
                })
            }
        }
    }
}

/// Human-readable undo report.
pub fn format_undo(release_id: &str, steps: &[UndoStep], dry_run: bool) -> String {
    let mut s = String::new();
    let mode = if dry_run { " (dry-run)" } else { "" };
    s.push_str(&format!("nornir release undo{mode} — release {release_id}\n\n"));
    if steps.is_empty() {
        s.push_str("  (nothing to reverse)\n");
        return s;
    }
    for st in steps {
        let mark = if st.partial { "⚠" } else { "↩" };
        s.push_str(&format!("  {mark} [{:>3}] {}: {}\n", st.seq, st.kind, st.action));
    }
    s
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::release::cargo::plan_version_bump;

    #[test]
    fn bump_record_undo_restores_file_byte_for_byte() {
        let dir = tempfile::tempdir().unwrap();
        let root = dir.path();
        let manifest = root.join("Cargo.toml");
        let original = "[package]\nname = \"x\"\nversion = \"0.1.0\"\nedition = \"2021\"\n\n[dependencies]\narrow = \"57\"\n";
        std::fs::write(&manifest, original).unwrap();

        let wh = IcebergWarehouse::open(&root.join("wh")).unwrap();
        let rec = ChangeRecorder::new("run-1");

        let plan = plan_version_bump(root, "arrow", "58.3.0", false).unwrap();
        assert!(!plan.edits.is_empty());
        record_bump(&wh, &rec, "x", &plan).unwrap();

        let after = std::fs::read_to_string(&manifest).unwrap();
        assert!(after.contains("arrow = \"58.3.0\""), "bump applied: {after}");
        assert_ne!(after, original);

        let paths: BTreeMap<String, PathBuf> = [("x".to_string(), root.to_path_buf())].into();
        let steps = undo_release(&wh, Some("run-1"), &paths, false, false).unwrap();
        assert!(steps.iter().any(|s| s.kind == "bump"));

        let restored = std::fs::read_to_string(&manifest).unwrap();
        assert_eq!(restored, original, "undo restored the manifest byte-for-byte");
    }

    #[test]
    fn patch_strip_record_undo_restores_block() {
        let dir = tempfile::tempdir().unwrap();
        let root = dir.path();
        let manifest = root.join("Cargo.toml");
        let original = "[package]\nname = \"x\"\nversion = \"0.1.0\"\n\n[dependencies]\niceberg = \"0.9\"\n\n[patch.crates-io]\niceberg = { path = \"../iceberg-arrow58\" }\n";
        std::fs::write(&manifest, original).unwrap();

        let wh = IcebergWarehouse::open(&root.join("wh")).unwrap();
        let rec = ChangeRecorder::new("run-2");

        let n = record_patch_strip(&wh, &rec, "x", &manifest).unwrap();
        assert_eq!(n, 1);
        let stripped = std::fs::read_to_string(&manifest).unwrap();
        assert!(!stripped.contains("[patch.crates-io]"), "patch stripped: {stripped}");

        let paths: BTreeMap<String, PathBuf> = [("x".to_string(), root.to_path_buf())].into();
        let steps = undo_release(&wh, Some("run-2"), &paths, false, false).unwrap();
        assert!(steps.iter().any(|s| s.kind == "patch_strip"));

        let restored = std::fs::read_to_string(&manifest).unwrap();
        assert_eq!(restored, original, "undo restored the [patch] block");
    }

    #[test]
    fn undo_reverses_newest_first_and_immutable_publish_is_partial() {
        let dir = tempfile::tempdir().unwrap();
        let wh = IcebergWarehouse::open(dir.path()).unwrap();
        let rec = ChangeRecorder::new("run-3");
        record_branch(&wh, &rec, "nornir", "release/staging", "abc123").unwrap();
        record_publish(&wh, &rec, "nornir", "nornir", "0.2.0", "crates.io", true).unwrap();

        let paths: BTreeMap<String, PathBuf> = BTreeMap::new();
        let steps = undo_release(&wh, Some("run-3"), &paths, true, false).unwrap();
        // Newest first: publish (seq 1) reversed before branch (seq 0).
        assert_eq!(steps[0].kind, "publish");
        assert!(steps[0].partial, "immutable publish → yank (partial)");
        assert_eq!(steps[1].kind, "branch");
    }

    #[test]
    fn undo_defaults_to_most_recent_run() {
        let dir = tempfile::tempdir().unwrap();
        let wh = IcebergWarehouse::open(dir.path()).unwrap();
        let rec = ChangeRecorder::new("only-run");
        record_branch(&wh, &rec, "r", "b", "").unwrap();
        let paths: BTreeMap<String, PathBuf> = BTreeMap::new();
        // No id → resolves to the latest run.
        let steps = undo_release(&wh, None, &paths, true, false).unwrap();
        assert_eq!(steps.len(), 1);
        assert_eq!(steps[0].kind, "branch");
    }
}