ryra-core 0.3.1

//! Backup planning. Pure functions that take service install state +
//! the user's backup config and produce typed plans the CLI executes.
//!
//! What lives here:
//! - [`BackupRunPlan`]: everything the CLI needs to push one service's
//!   data to the configured restic repository.
//! - [`BackupRestorePlan`]: same shape for the reverse operation.
//! - [`plan_backup_run`] / [`plan_backup_restore`]: the planners.
//!
//! What does *not* live here: spawning the `restic` subprocess, running
//! hook scripts, or any other side effect. The CLI layer owns those.
//! Keeping the planner pure means it round-trips cleanly in tests
//! against a tempdir without needing restic on the test runner.

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

use sha2::{Digest, Sha256};

use crate::config::schema::{BackupBackend, Config};
use crate::data::classify::classify_home_dir;
use crate::error::{Error, Result};
use crate::metadata::{Metadata, load_metadata};
use crate::paths::service_home;
use crate::registry;
use crate::registry::service_def::{BackupConfig, ServiceDef};

const SERVICE_TOML_FILENAME: &str = "service.toml";

/// Concrete instructions for backing up one installed service.
///
/// The CLI consumes this by:
/// 1. Running every `pre_backup_hook` script in order.
/// 2. Spawning `restic backup` with `repo`, `password` (via
///    `RESTIC_PASSWORD` env), `env` set on the child, `--tag` for each
///    string in `tags`, and `--exclude` for each string in `excludes`,
///    with `paths` as the positional arguments.
/// 3. Running every `post_backup_hook` (even if step 2 failed —
///    failure-cleanup matters; see [`PlanHook::Cleanup`]).
#[derive(Debug, Clone)]
pub struct BackupRunPlan {
    pub service_name: String,
    pub service_home: PathBuf,
    pub repo: String,
    pub password: String,
    pub env: BTreeMap<String, String>,
    pub tags: Vec<String>,
    pub paths: Vec<PathBuf>,
    pub excludes: Vec<String>,
    pub pre_backup_hook: Option<PathBuf>,
    pub post_backup_hook: Option<PathBuf>,
}

/// Instructions for restoring one installed service from a specific
/// restic snapshot.
#[derive(Debug, Clone)]
pub struct BackupRestorePlan {
    pub service_name: String,
    pub service_home: PathBuf,
    pub repo: String,
    pub password: String,
    pub env: BTreeMap<String, String>,
    /// `latest` to grab the newest snapshot, or a specific restic
    /// snapshot id (hex prefix) when the user passed `--at <id>`.
    pub snapshot: String,
    pub pre_restore_hook: Option<PathBuf>,
    pub post_restore_hook: Option<PathBuf>,
}

/// Plan a `ryra backup run <service>` invocation. Errors loudly when:
/// - the service isn't installed,
/// - its install metadata didn't opt into backups (`--backup` wasn't
///   passed at `ryra add`),
/// - the user hasn't run `ryra backup configure` yet,
/// - the service author hasn't declared backup support (defensive —
///   the install-time check should have caught this earlier, but a
///   manifest change between install and backup is possible).
pub fn plan_backup_run(
    service_name: &str,
    config: &Config,
    repo_dir: &Path,
) -> Result<BackupRunPlan> {
    let metadata = load_install_metadata(service_name)?;
    if !metadata.backup_enabled {
        return Err(Error::BackupNotEnabled(service_name.to_string()));
    }
    let settings = config
        .backup
        .as_ref()
        .ok_or(Error::BackupRepoNotConfigured)?;

    let svc = registry::find_service(repo_dir, service_name)?;
    if !svc.def.integrations.backup {
        return Err(Error::BackupNotSupported(service_name.to_string()));
    }

    let home = service_home(service_name)?;
    let (paths, excludes) = resolve_paths(&svc.def, &home)?;

    let manifest_sha = manifest_sha256(&svc.service_dir);
    let mut tags = vec![format!("service:{service_name}")];
    tags.push(format!("manifest_sha:{}", &manifest_sha[..16]));

    let backup = svc.def.backup.as_ref();
    let pre = resolve_hook(
        backup.and_then(|b| b.pre_backup.as_deref()),
        &home,
        "backup-pre.sh",
    );
    let post = resolve_hook(
        backup.and_then(|b| b.post_backup.as_deref()),
        &home,
        "backup-post.sh",
    );

    Ok(BackupRunPlan {
        service_name: service_name.to_string(),
        service_home: home,
        repo: settings.backend.restic_repo(),
        password: settings.password.clone(),
        env: backend_env_map(&settings.backend),
        tags,
        paths,
        excludes,
        pre_backup_hook: pre,
        post_backup_hook: post,
    })
}

/// Plan a `ryra backup restore <service>` invocation.
///
/// `snapshot` is either `latest` (newest snapshot tagged with this
/// service) or an explicit restic snapshot id. The CLI resolves the
/// actual id by querying restic; this planner stays pure and just
/// passes the user's choice through.
pub fn plan_backup_restore(
    service_name: &str,
    snapshot: &str,
    config: &Config,
    repo_dir: &Path,
) -> Result<BackupRestorePlan> {
    let metadata = load_install_metadata(service_name)?;
    if !metadata.backup_enabled {
        return Err(Error::BackupNotEnabled(service_name.to_string()));
    }
    let settings = config
        .backup
        .as_ref()
        .ok_or(Error::BackupRepoNotConfigured)?;

    let svc = registry::find_service(repo_dir, service_name)?;
    let home = service_home(service_name)?;

    let backup = svc.def.backup.as_ref();
    let pre = resolve_hook(
        backup.and_then(|b| b.pre_restore.as_deref()),
        &home,
        "restore-pre.sh",
    );
    let post = resolve_hook(
        backup.and_then(|b| b.post_restore.as_deref()),
        &home,
        "restore-post.sh",
    );

    Ok(BackupRestorePlan {
        service_name: service_name.to_string(),
        service_home: home,
        repo: settings.backend.restic_repo(),
        password: settings.password.clone(),
        env: backend_env_map(&settings.backend),
        snapshot: snapshot.to_string(),
        pre_restore_hook: pre,
        post_restore_hook: post,
    })
}

/// List installed services that have `backup_enabled = true` in their
/// metadata. The CLI's `ryra backup run` (no service argument) uses
/// this to iterate every enabled install.
pub fn list_backup_enabled() -> Result<Vec<String>> {
    let root = crate::paths::service_data_root()?;
    if !root.is_dir() {
        return Ok(Vec::new());
    }
    let mut out = Vec::new();
    for entry in std::fs::read_dir(&root).map_err(|source| Error::FileRead {
        path: root.clone(),
        source,
    })? {
        let entry = entry.map_err(|source| Error::FileRead {
            path: root.clone(),
            source,
        })?;
        let name = match entry.file_name().to_str() {
            Some(s) => s.to_string(),
            None => continue,
        };
        if let Some(meta) = load_metadata(&name)?
            && meta.backup_enabled
        {
            out.push(name);
        }
    }
    out.sort();
    Ok(out)
}

fn load_install_metadata(service_name: &str) -> Result<Metadata> {
    load_metadata(service_name)?.ok_or_else(|| Error::ServiceNotInstalled(service_name.to_string()))
}

/// Resolve the set of absolute paths to feed restic, plus the list of
/// `--exclude` patterns.
///
/// Two routes:
/// - Explicit `[backup].paths`: trust the manifest, resolve each
///   entry against the service home.
/// - No explicit paths: ask the classifier "what's data here?" — that
///   covers every top-level child not in the install manifest (the
///   `data/` directory, the `db-data/` directory, anything the user
///   has dropped in). Also include `.backup/` if the manifest declared
///   any pre_backup hook, since that's the convention for dumping.
fn resolve_paths(def: &ServiceDef, home: &Path) -> Result<(Vec<PathBuf>, Vec<String>)> {
    let backup = def.backup.as_ref();
    let excludes: Vec<String> = backup.map(|b| b.exclude.clone()).unwrap_or_default();

    if let Some(b) = backup
        && !b.paths.is_empty()
    {
        let abs: Vec<PathBuf> = b.paths.iter().map(|p| home.join(p)).collect();
        return Ok((abs, excludes));
    }

    // Default: classifier-derived data paths.
    let (data, _ephemeral) = classify_home_dir(home)?;
    let mut paths: Vec<PathBuf> = data;

    // If a hook is declared, it writes to .backup/ — include it if
    // present at backup time. We add it conditionally rather than
    // unconditionally so a service that never created the dir doesn't
    // make restic complain about a missing path.
    if backup.is_some_and(has_any_backup_hook) {
        let dump_dir = home.join(".backup");
        if dump_dir.exists() && !paths.iter().any(|p| p == &dump_dir) {
            paths.push(dump_dir);
        }
    }

    paths.sort();
    Ok((paths, excludes))
}

fn has_any_backup_hook(b: &BackupConfig) -> bool {
    b.pre_backup.is_some() || b.post_backup.is_some()
}

fn hook_path(home: &Path, filename: &str) -> PathBuf {
    home.join("configs").join("scripts").join(filename)
}

/// Decide which hook script (if any) to invoke for a given lifecycle
/// phase. Priority:
/// 1. Explicit `[backup].pre_backup` (or sibling) in service.toml.
/// 2. Convention: `configs/scripts/<phase>.sh` on disk.
/// 3. None — phase is a no-op.
///
/// The convention path means a typical service.toml's `[backup]`
/// section is a single `paths = [...]` line; the four hook scripts
/// are auto-discovered when their conventional names are present in
/// `configs/scripts/`, and authors never have to repeat the
/// filenames in the manifest.
fn resolve_hook(explicit: Option<&str>, home: &Path, conventional: &str) -> Option<PathBuf> {
    if let Some(name) = explicit {
        return Some(hook_path(home, name));
    }
    let conv = hook_path(home, conventional);
    if conv.exists() { Some(conv) } else { None }
}

fn backend_env_map(backend: &BackupBackend) -> BTreeMap<String, String> {
    backend
        .env()
        .into_iter()
        .map(|(k, v)| (k.to_string(), v))
        .collect()
}

/// Hex SHA256 of the service's `service.toml`. Used as the
/// `manifest_sha:` tag on each snapshot so a future restore can detect
/// version skew between the snapshot and the currently-installed
/// service definition.
///
/// Falls back to an all-zero hash if the file can't be read — the
/// caller's higher-level error handling will already have failed for
/// other reasons, and a sentinel hash is more useful than panicking.
pub fn manifest_sha256(service_dir: &Path) -> String {
    let path = service_dir.join(SERVICE_TOML_FILENAME);
    let bytes = match std::fs::read(&path) {
        Ok(b) => b,
        Err(_) => return "0".repeat(64),
    };
    let mut hasher = Sha256::new();
    hasher.update(&bytes);
    let digest = hasher.finalize();
    hex_encode(&digest)
}

fn hex_encode(bytes: &[u8]) -> String {
    const HEX: &[u8; 16] = b"0123456789abcdef";
    let mut s = String::with_capacity(bytes.len() * 2);
    for b in bytes {
        s.push(HEX[(b >> 4) as usize] as char);
        s.push(HEX[(b & 0xf) as usize] as char);
    }
    s
}

#[cfg(test)]
mod tests {
    use super::*;
    use crate::config::schema::{BackupBackend, BackupSettings};
    use crate::registry::service_def::{
        Arch, HttpsRequirement, IntegrationFlags, PortDef, ServiceDef, ServiceMeta,
    };

    fn def_with_backup(backup_section: Option<BackupConfig>) -> ServiceDef {
        ServiceDef {
            service: ServiceMeta {
                name: "demo".into(),
                description: "demo".into(),
                url: None,
                kind: Default::default(),
                architecture: vec![Arch::Amd64, Arch::Arm64],
                https: HttpsRequirement::default(),
            },
            requirements: None,
            ports: vec![PortDef {
                name: "http".into(),
                container_port: 80,
                host_port: None,
                protocol: Default::default(),
            }],
            env: vec![],
            env_groups: vec![],
            requires: vec![],
            mappings: Default::default(),
            integrations: IntegrationFlags {
                backup: backup_section.is_some(),
                ..Default::default()
            },
            capabilities: Default::default(),
            backup: backup_section,
        }
    }

    #[test]
    fn resolve_paths_uses_classifier_when_paths_empty() {
        let dir = tempfile::tempdir().unwrap();
        let home = dir.path();
        std::fs::create_dir(home.join("data")).unwrap();
        std::fs::create_dir(home.join("cache")).unwrap();
        // No manifest — classifier treats everything as data.
        let def = def_with_backup(Some(BackupConfig::default()));
        let (paths, excludes) = resolve_paths(&def.clone(), home).unwrap();
        let names: Vec<String> = paths
            .iter()
            .map(|p| p.file_name().unwrap().to_string_lossy().into_owned())
            .collect();
        assert!(names.contains(&"data".to_string()), "got {names:?}");
        assert!(names.contains(&"cache".to_string()), "got {names:?}");
        assert!(excludes.is_empty());
    }

    #[test]
    fn resolve_paths_honours_explicit_list() {
        let dir = tempfile::tempdir().unwrap();
        let home = dir.path();
        let def = def_with_backup(Some(BackupConfig {
            paths: vec!["data/uploads".into(), ".backup/db.sql".into()],
            exclude: vec!["data/uploads/cache".into()],
            ..Default::default()
        }));
        let (paths, excludes) = resolve_paths(&def, home).unwrap();
        assert_eq!(
            paths,
            vec![home.join("data/uploads"), home.join(".backup/db.sql")]
        );
        assert_eq!(excludes, vec!["data/uploads/cache"]);
    }

    #[test]
    fn resolve_paths_includes_dot_backup_when_hook_declared() {
        let dir = tempfile::tempdir().unwrap();
        let home = dir.path();
        std::fs::create_dir(home.join("data")).unwrap();
        std::fs::create_dir(home.join(".backup")).unwrap();
        // Hook declared but no explicit paths → classifier output
        // plus .backup/.
        let def = def_with_backup(Some(BackupConfig {
            pre_backup: Some("dump.sh".into()),
            ..Default::default()
        }));
        let (paths, _) = resolve_paths(&def, home).unwrap();
        let names: Vec<String> = paths
            .iter()
            .map(|p| p.file_name().unwrap().to_string_lossy().into_owned())
            .collect();
        assert!(names.contains(&".backup".to_string()), "got {names:?}");
        assert!(names.contains(&"data".to_string()), "got {names:?}");
    }

    #[test]
    fn hook_path_resolves_under_configs_scripts() {
        let home = PathBuf::from("/x/y");
        assert_eq!(
            hook_path(&home, "backup-pre.sh"),
            PathBuf::from("/x/y/configs/scripts/backup-pre.sh")
        );
    }

    #[test]
    fn resolve_hook_prefers_explicit_over_convention() {
        let dir = tempfile::tempdir().unwrap();
        let home = dir.path();
        // Both the conventional and a custom-named file exist; the
        // explicit field wins.
        let scripts = home.join("configs").join("scripts");
        std::fs::create_dir_all(&scripts).unwrap();
        std::fs::write(scripts.join("backup-pre.sh"), "#!/bin/sh\n").unwrap();
        std::fs::write(scripts.join("custom.sh"), "#!/bin/sh\n").unwrap();
        let resolved = resolve_hook(Some("custom.sh"), home, "backup-pre.sh");
        assert_eq!(resolved.unwrap().file_name().unwrap(), "custom.sh");
    }

    #[test]
    fn resolve_hook_falls_back_to_convention_when_present() {
        let dir = tempfile::tempdir().unwrap();
        let home = dir.path();
        let scripts = home.join("configs").join("scripts");
        std::fs::create_dir_all(&scripts).unwrap();
        std::fs::write(scripts.join("backup-pre.sh"), "#!/bin/sh\n").unwrap();
        let resolved = resolve_hook(None, home, "backup-pre.sh");
        assert_eq!(resolved.unwrap().file_name().unwrap(), "backup-pre.sh");
    }

    #[test]
    fn resolve_hook_returns_none_when_no_script_exists() {
        let dir = tempfile::tempdir().unwrap();
        // No configs/scripts/ at all → no hook to run.
        assert!(resolve_hook(None, dir.path(), "backup-pre.sh").is_none());
    }

    #[test]
    fn manifest_sha256_changes_with_content() {
        let a = tempfile::tempdir().unwrap();
        let b = tempfile::tempdir().unwrap();
        std::fs::write(a.path().join("service.toml"), "v1").unwrap();
        std::fs::write(b.path().join("service.toml"), "v2").unwrap();
        assert_ne!(manifest_sha256(a.path()), manifest_sha256(b.path()));
    }

    #[test]
    fn manifest_sha256_stable_for_identical_content() {
        let a = tempfile::tempdir().unwrap();
        let b = tempfile::tempdir().unwrap();
        std::fs::write(a.path().join("service.toml"), "same").unwrap();
        std::fs::write(b.path().join("service.toml"), "same").unwrap();
        assert_eq!(manifest_sha256(a.path()), manifest_sha256(b.path()));
    }

    #[test]
    fn manifest_sha256_returns_zero_hash_on_missing_file() {
        let dir = tempfile::tempdir().unwrap();
        assert_eq!(manifest_sha256(dir.path()), "0".repeat(64));
    }

    #[test]
    fn backend_env_map_round_trips_aws_creds() {
        let settings = BackupSettings {
            password: "p".into(),
            backend: BackupBackend::S3 {
                endpoint: "http://h:9000".into(),
                bucket: "b".into(),
                access_key_id: "id".into(),
                secret_access_key: "secret".into(),
                prefix: None,
            },
        };
        let env = backend_env_map(&settings.backend);
        assert_eq!(env.get("AWS_ACCESS_KEY_ID"), Some(&"id".to_string()));
        assert_eq!(
            env.get("AWS_SECRET_ACCESS_KEY"),
            Some(&"secret".to_string())
        );
    }
}