//! Declarative project manifest (`picloud.toml`).
//!
//! One manifest describes the desired state of a **single app** — its
//! scripts, routes, triggers, and the *names* of the secrets it expects
//! (values are pushed out-of-band via `pic secret set`, never committed).
//!
//! This is the foundation of the declarative project tool (`pic pull` /
//! `pic plan` / `pic apply`). The types deliberately reuse `picloud_shared`
//! enums (`HostKind`, `PathKind`, `DispatchMode`, `ScriptKind`,
//! `ScriptSandbox`, the event-op enums) so the manifest's wire shape stays
//! identical to the admin API — the CLI never depends on `manager-core`.
//!
//! All eight trigger kinds are representable except `dead_letter` (not
//! exposed declaratively). `email` triggers carry an `inbound_secret_ref`
//! (a secret name) resolved server-side at apply.

use std::collections::BTreeMap;
use std::fs;
use std::path::Path;

use anyhow::{Context, Result};
use picloud_shared::{
    DispatchMode, DocsEventOp, FilesEventOp, HostKind, KvEventOp, PathKind, ScriptKind,
    ScriptSandbox,
};
use serde::{Deserialize, Serialize};

/// Conventional manifest filename at a project root.
pub const MANIFEST_FILE: &str = "picloud.toml";

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct Manifest {
    /// An app node declares `[app]`; a group node declares `[group]` (Phase 5).
    /// Exactly one is present (enforced by [`Manifest::parse`]).
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub app: Option<ManifestApp>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub group: Option<ManifestGroup>,
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub scripts: Vec<ManifestScript>,
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub routes: Vec<ManifestRoute>,
    #[serde(default, skip_serializing_if = "ManifestTriggers::is_empty")]
    pub triggers: ManifestTriggers,
    #[serde(default, skip_serializing_if = "ManifestSecrets::is_empty")]
    pub secrets: ManifestSecrets,
    /// `[vars]` — app config key → value, reconciled at app scope `*`. Values
    /// are non-secret and live inline (unlike `[secrets]`, which is name-only).
    /// The overlay merges per-env, last-write-wins by key.
    #[serde(default, skip_serializing_if = "BTreeMap::is_empty")]
    pub vars: BTreeMap<String, toml::Value>,
    /// `[[extension_points]]` — module names this node opens for per-tenant
    /// resolution (§5.5). Allowed on both app and group manifests.
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub extension_points: Vec<ManifestExtensionPoint>,
}

impl Manifest {
    /// Parse a manifest from TOML text. Enforces the app-XOR-group invariant.
    pub fn parse(text: &str) -> Result<Self> {
        let m: Self = toml::from_str(text).context("parsing manifest TOML")?;
        match (&m.app, &m.group) {
            (Some(_), None) | (None, Some(_)) => {}
            (Some(_), Some(_)) => {
                anyhow::bail!(
                    "manifest declares both [app] and [group]; a node is one or the other"
                )
            }
            (None, None) => {
                anyhow::bail!("manifest declares neither [app] nor [group]")
            }
        }
        // A group node owns only scripts + vars (+ secret names) — routes and
        // triggers are app concerns. Reject them early with a clear message.
        if m.group.is_some() {
            if !m.routes.is_empty() {
                anyhow::bail!(
                    "a [group] manifest cannot declare [[routes]] — routes bind to an app"
                );
            }
            if !m.triggers.is_empty() {
                anyhow::bail!(
                    "a [group] manifest cannot declare [[triggers]] — triggers belong to an app"
                );
            }
        }
        Ok(m)
    }

    /// This node's slug (app or group).
    #[must_use]
    pub fn slug(&self) -> &str {
        match (&self.app, &self.group) {
            (Some(a), _) => &a.slug,
            (_, Some(g)) => &g.slug,
            _ => "",
        }
    }

    /// True iff this manifest declares a `[group]` node (Phase 5).
    #[must_use]
    pub fn is_group(&self) -> bool {
        self.group.is_some()
    }

    /// Load and parse the manifest at `path`.
    pub fn load(path: &Path) -> Result<Self> {
        let body =
            fs::read_to_string(path).with_context(|| format!("reading {}", path.display()))?;
        Self::parse(&body)
    }

    /// Render to TOML text. Tables are emitted after scalars (the struct
    /// field order already satisfies TOML's "values before tables" rule).
    pub fn to_toml(&self) -> Result<String> {
        toml::to_string_pretty(self).context("serializing manifest TOML")
    }

    /// Load the base manifest, then (if `env` is set) merge the sparse
    /// `picloud.<env>.toml` overlay on top — the §4.1 base+overlay model
    /// where "an environment is an app". The overlay carries per-env slug,
    /// secrets, and vars (overlay vars win per key); scripts/routes/triggers
    /// stay in the shared base.
    pub fn load_with_env(base_path: &Path, env: Option<&str>) -> Result<Self> {
        let mut base = Self::load(base_path)?;
        if let Some(env) = env {
            let path = overlay_path(base_path, env);
            let body = fs::read_to_string(&path).with_context(|| {
                format!(
                    "reading overlay {} for env `{env}` (expected next to the base manifest)",
                    path.display()
                )
            })?;
            let overlay: ManifestOverlay = toml::from_str(&body)
                .with_context(|| format!("parsing overlay {}", path.display()))?;
            base.apply_overlay(overlay);
        }
        Ok(base)
    }

    /// Merge a sparse overlay onto this manifest: overlay `app.slug`/`name`
    /// replace the base's; overlay secret names union into the base set.
    fn apply_overlay(&mut self, overlay: ManifestOverlay) {
        if let Some(app) = &mut self.app {
            if let Some(slug) = overlay.app.slug {
                app.slug = slug;
            }
            if let Some(name) = overlay.app.name {
                app.name = name;
            }
        }
        for n in overlay.secrets.names {
            if !self.secrets.names.contains(&n) {
                self.secrets.names.push(n);
            }
        }
        // Overlay vars override base vars per key (the env-specific value of
        // an env-agnostic default); keys only in the base are kept.
        for (k, v) in overlay.vars {
            self.vars.insert(k, v);
        }
    }
}

/// `picloud.toml` → `picloud.<env>.toml`, alongside the base (works for a
/// custom `--file` too: `custom.toml` → `custom.<env>.toml`).
fn overlay_path(base_path: &Path, env: &str) -> std::path::PathBuf {
    let parent = base_path.parent().unwrap_or_else(|| Path::new("."));
    let name = base_path
        .file_name()
        .map(|n| n.to_string_lossy().into_owned())
        .unwrap_or_else(|| MANIFEST_FILE.to_string());
    let stem = name.strip_suffix(".toml").unwrap_or(&name);
    parent.join(format!("{stem}.{env}.toml"))
}

/// A sparse per-environment overlay (`picloud.<env>.toml`). Only the fields
/// that vary per environment today — slug/name and secret names.
///
/// `deny_unknown_fields`: an overlay can carry *only* `[app]`, `[secrets]`,
/// and `[vars]`. Scripts/routes/triggers belong in the shared base manifest,
/// so a `[[scripts]]`/`[[routes]]`/`[[triggers]]` table (or a typo'd key) in
/// an overlay is a mistake — error loudly rather than silently dropping it.
#[derive(Debug, Clone, Default, Deserialize)]
#[serde(deny_unknown_fields)]
pub struct ManifestOverlay {
    #[serde(default)]
    pub app: OverlayApp,
    #[serde(default)]
    pub secrets: ManifestSecrets,
    #[serde(default)]
    pub vars: BTreeMap<String, toml::Value>,
}

#[derive(Debug, Clone, Default, Deserialize)]
#[serde(deny_unknown_fields)]
pub struct OverlayApp {
    #[serde(default)]
    pub slug: Option<String>,
    #[serde(default)]
    pub name: Option<String>,
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct ManifestApp {
    pub slug: String,
    pub name: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub description: Option<String>,
}

/// A `[group]` node (Phase 5): a group's own declarative content — its scripts
/// and `[vars]`. The group must already exist on the server (created with
/// `pic groups create`); the manifest reconciles its content, not the tree
/// shape. In a nested project the parent is inferred from the directory tree.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct ManifestGroup {
    pub slug: String,
    pub name: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub description: Option<String>,
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct ManifestScript {
    pub name: String,
    /// Path to the `.rhai` source, relative to the manifest's directory.
    pub file: String,
    #[serde(default, skip_serializing_if = "is_endpoint")]
    pub kind: ScriptKind,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub description: Option<String>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub timeout_seconds: Option<i32>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub memory_limit_mb: Option<i32>,
    /// Per-script sandbox overrides; omitted entirely when no knob is set.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub sandbox: Option<ScriptSandbox>,
    /// Three-state lifecycle (§4.3): `false` deploys the script inert (not
    /// invocable). Omitted ⇒ active; only serialized when disabled.
    #[serde(
        default = "picloud_shared::default_true",
        skip_serializing_if = "is_true"
    )]
    pub enabled: bool,
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct ManifestRoute {
    /// Name of the script this route binds to.
    pub script: String,
    /// HTTP method; omit for ANY.
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub method: Option<String>,
    pub host_kind: HostKind,
    #[serde(default, skip_serializing_if = "String::is_empty")]
    pub host: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub host_param_name: Option<String>,
    pub path_kind: PathKind,
    pub path: String,
    #[serde(default, skip_serializing_if = "is_sync")]
    pub dispatch_mode: DispatchMode,
    /// Three-state lifecycle (§4.3): `false` deploys the route inert (404).
    /// Omitted ⇒ active; only serialized when disabled.
    #[serde(
        default = "picloud_shared::default_true",
        skip_serializing_if = "is_true"
    )]
    pub enabled: bool,
}

/// Triggers grouped by kind (arrays-of-tables: `[[triggers.cron]]`, …).
#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
pub struct ManifestTriggers {
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub kv: Vec<KvTriggerSpec>,
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub docs: Vec<DocsTriggerSpec>,
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub files: Vec<FilesTriggerSpec>,
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub cron: Vec<CronTriggerSpec>,
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub pubsub: Vec<PubsubTriggerSpec>,
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub email: Vec<EmailTriggerSpec>,
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub queue: Vec<QueueTriggerSpec>,
}

impl ManifestTriggers {
    #[must_use]
    pub fn is_empty(&self) -> bool {
        self.kv.is_empty()
            && self.docs.is_empty()
            && self.files.is_empty()
            && self.cron.is_empty()
            && self.pubsub.is_empty()
            && self.email.is_empty()
            && self.queue.is_empty()
    }
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct KvTriggerSpec {
    pub script: String,
    pub collection_glob: String,
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub ops: Vec<KvEventOp>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub dispatch_mode: Option<DispatchMode>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub retry_max_attempts: Option<u32>,
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct DocsTriggerSpec {
    pub script: String,
    pub collection_glob: String,
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub ops: Vec<DocsEventOp>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub dispatch_mode: Option<DispatchMode>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub retry_max_attempts: Option<u32>,
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct FilesTriggerSpec {
    pub script: String,
    pub collection_glob: String,
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub ops: Vec<FilesEventOp>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub dispatch_mode: Option<DispatchMode>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub retry_max_attempts: Option<u32>,
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct CronTriggerSpec {
    pub script: String,
    /// 6-field cron expression (with seconds).
    pub schedule: String,
    #[serde(default = "default_timezone")]
    pub timezone: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub dispatch_mode: Option<DispatchMode>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub retry_max_attempts: Option<u32>,
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct PubsubTriggerSpec {
    pub script: String,
    pub topic_pattern: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub dispatch_mode: Option<DispatchMode>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub retry_max_attempts: Option<u32>,
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct EmailTriggerSpec {
    pub script: String,
    /// Name of the secret (set via `pic secret set`) holding the inbound
    /// HMAC value — resolved + sealed server-side at apply. Never the value.
    pub inbound_secret_ref: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub dispatch_mode: Option<DispatchMode>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub retry_max_attempts: Option<u32>,
}

#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct QueueTriggerSpec {
    pub script: String,
    pub queue_name: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub visibility_timeout_secs: Option<u32>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub dispatch_mode: Option<DispatchMode>,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub retry_max_attempts: Option<u32>,
}

/// `[secrets] names = [...]` — declares which secrets the app expects.
/// Values are never in the manifest; `pic secret set` pushes them.
#[derive(Debug, Clone, Default, PartialEq, Serialize, Deserialize)]
pub struct ManifestSecrets {
    #[serde(default, skip_serializing_if = "Vec::is_empty")]
    pub names: Vec<String>,
}

impl ManifestSecrets {
    #[must_use]
    pub fn is_empty(&self) -> bool {
        self.names.is_empty()
    }
}

/// `[[extension_points]]` — a module name opened for per-tenant resolution
/// (§5.5). A parent/group script importing `name` resolves it against the
/// inheriting app's module instead of the sealed lexical chain; `default`
/// names a local module used when an app provides none.
#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
pub struct ManifestExtensionPoint {
    pub name: String,
    #[serde(default, skip_serializing_if = "Option::is_none")]
    pub default: Option<String>,
}

// ---- serde skip/default helpers ----

fn is_endpoint(kind: &ScriptKind) -> bool {
    *kind == ScriptKind::Endpoint
}

fn is_sync(mode: &DispatchMode) -> bool {
    *mode == DispatchMode::Sync
}

/// Skip-serialize helper: `enabled` defaults true, so only emit it when false.
fn is_true(b: &bool) -> bool {
    *b
}

fn default_timezone() -> String {
    "UTC".to_string()
}

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

    fn sample() -> Manifest {
        Manifest {
            app: Some(ManifestApp {
                slug: "blog".into(),
                name: "My Blog".into(),
                description: Some("demo".into()),
            }),
            group: None,
            scripts: vec![
                ManifestScript {
                    name: "create-post".into(),
                    file: "scripts/create-post.rhai".into(),
                    kind: ScriptKind::Endpoint,
                    description: None,
                    timeout_seconds: Some(10),
                    memory_limit_mb: Some(256),
                    sandbox: None,
                    enabled: true,
                },
                ManifestScript {
                    name: "lib".into(),
                    file: "scripts/lib.rhai".into(),
                    kind: ScriptKind::Module,
                    description: None,
                    timeout_seconds: None,
                    memory_limit_mb: None,
                    sandbox: Some(ScriptSandbox {
                        max_operations: Some(5_000_000),
                        ..ScriptSandbox::empty()
                    }),
                    enabled: false,
                },
            ],
            routes: vec![ManifestRoute {
                script: "create-post".into(),
                method: Some("POST".into()),
                host_kind: HostKind::Any,
                host: String::new(),
                host_param_name: None,
                path_kind: PathKind::Exact,
                path: "/posts".into(),
                dispatch_mode: DispatchMode::Sync,
                enabled: true,
            }],
            triggers: ManifestTriggers {
                cron: vec![CronTriggerSpec {
                    script: "create-post".into(),
                    schedule: "0 6 * * * *".into(),
                    timezone: "UTC".into(),
                    dispatch_mode: None,
                    retry_max_attempts: None,
                }],
                kv: vec![KvTriggerSpec {
                    script: "create-post".into(),
                    collection_glob: "users".into(),
                    ops: vec![KvEventOp::Insert, KvEventOp::Update],
                    dispatch_mode: Some(DispatchMode::Async),
                    retry_max_attempts: Some(5),
                }],
                ..ManifestTriggers::default()
            },
            secrets: ManifestSecrets {
                names: vec!["STRIPE_KEY".into()],
            },
            vars: BTreeMap::from([
                ("region".to_string(), toml::Value::String("eu".into())),
                ("max-retries".to_string(), toml::Value::Integer(3)),
            ]),
            extension_points: vec![ManifestExtensionPoint {
                name: "theme".into(),
                default: Some("default-theme".into()),
            }],
        }
    }

    #[test]
    fn round_trips_through_toml() {
        let m = sample();
        let text = m.to_toml().expect("serialize");
        let back = Manifest::parse(&text).expect("parse");
        assert_eq!(m, back, "manifest must survive a TOML round-trip");
    }

    #[test]
    fn omits_defaulted_fields() {
        let text = sample().to_toml().unwrap();
        // Endpoint kind + sync dispatch are defaults → not emitted.
        assert!(
            !text.contains("kind = \"endpoint\""),
            "default kind should be omitted:\n{text}"
        );
        assert!(
            !text.contains("dispatch_mode = \"sync\""),
            "default route dispatch should be omitted:\n{text}"
        );
        // Module kind IS non-default → emitted.
        assert!(text.contains("kind = \"module\""), "got:\n{text}");
        // `enabled` defaults true → omitted for the active script/route, but
        // the disabled `lib` script emits `enabled = false`.
        assert!(
            text.contains("enabled = false"),
            "a disabled entity must emit enabled:\n{text}"
        );
        assert!(
            !text.contains("enabled = true"),
            "active entities must omit the default:\n{text}"
        );
    }

    #[test]
    fn overlay_merges_slug_and_unions_secrets() {
        let mut m = sample(); // slug "blog", secrets ["STRIPE_KEY"]
        let overlay: ManifestOverlay = toml::from_str(
            "[app]\nslug = \"blog-staging\"\n\n[secrets]\nnames = [\"STRIPE_KEY\", \"STAGING_ONLY\"]\n",
        )
        .unwrap();
        m.apply_overlay(overlay);
        let app = m.app.as_ref().unwrap();
        assert_eq!(app.slug, "blog-staging", "overlay slug wins");
        assert_eq!(app.name, "My Blog", "base name kept when overlay omits it");
        assert_eq!(
            m.secrets.names,
            vec!["STRIPE_KEY".to_string(), "STAGING_ONLY".to_string()],
            "secrets union, no dupes"
        );
        // Scripts/routes come from the base, untouched by the overlay.
        assert_eq!(m.scripts.len(), 2);
    }

    #[test]
    fn overlay_rejects_non_overlay_tables() {
        // An overlay carries only [app]/[secrets]. Scripts/routes/triggers
        // belong in the shared base, so a `[[scripts]]` table (or a typo'd
        // key) in an overlay must error loudly, not be silently dropped.
        let err = toml::from_str::<ManifestOverlay>(
            "[app]\nslug = \"blog-staging\"\n\n\
             [[scripts]]\nname = \"hello\"\nfile = \"scripts/hello.rhai\"\n",
        )
        .expect_err("overlay with [[scripts]] must be rejected");
        assert!(
            err.to_string().contains("scripts") || err.to_string().contains("unknown"),
            "error should point at the offending table: {err}"
        );

        // Typo'd key inside [app] is likewise rejected.
        toml::from_str::<ManifestOverlay>("[app]\nslag = \"oops\"\n")
            .expect_err("overlay with a typo'd [app] key must be rejected");
    }

    #[test]
    fn overlay_path_derivation() {
        assert_eq!(
            overlay_path(Path::new("proj/picloud.toml"), "staging"),
            Path::new("proj/picloud.staging.toml")
        );
        assert_eq!(
            overlay_path(Path::new("custom.toml"), "prod"),
            Path::new("custom.prod.toml")
        );
    }

    #[test]
    fn empty_optional_sections_omitted() {
        let m = Manifest {
            app: Some(ManifestApp {
                slug: "x".into(),
                name: "X".into(),
                description: None,
            }),
            group: None,
            scripts: vec![],
            routes: vec![],
            triggers: ManifestTriggers::default(),
            secrets: ManifestSecrets::default(),
            vars: BTreeMap::new(),
            extension_points: Vec::new(),
        };
        let text = m.to_toml().unwrap();
        assert!(!text.contains("[[scripts]]"), "got:\n{text}");
        assert!(!text.contains("triggers"), "got:\n{text}");
        assert!(!text.contains("secrets"), "got:\n{text}");
        assert!(!text.contains("vars"), "got:\n{text}");
        assert!(!text.contains("extension_points"), "got:\n{text}");
        // Still round-trips.
        assert_eq!(m, Manifest::parse(&text).unwrap());
    }

    #[test]
    fn group_manifest_parses_and_rejects_app_only_blocks() {
        // A [group] node: scripts + vars, no [app].
        let m = Manifest::parse(
            "[group]\nslug = \"acme\"\nname = \"ACME\"\n\n\
             [[scripts]]\nname = \"shared\"\nfile = \"scripts/shared.rhai\"\n\n\
             [vars]\nregion = \"eu\"\n",
        )
        .expect("group manifest parses");
        assert!(m.is_group());
        assert_eq!(m.slug(), "acme");
        assert_eq!(m.scripts.len(), 1);

        // A group cannot carry routes/triggers.
        let err = Manifest::parse(
            "[group]\nslug = \"acme\"\nname = \"ACME\"\n\n\
             [[routes]]\nscript = \"shared\"\nhost_kind = \"any\"\npath_kind = \"exact\"\npath = \"/x\"\n",
        )
        .expect_err("group with routes is rejected");
        assert!(err.to_string().contains("routes"), "got: {err}");

        // Neither / both is rejected.
        Manifest::parse("[vars]\nx = 1\n").expect_err("no [app] or [group]");
        Manifest::parse("[app]\nslug=\"a\"\nname=\"A\"\n[group]\nslug=\"g\"\nname=\"G\"\n")
            .expect_err("both [app] and [group]");
    }

    #[test]
    fn overlay_vars_override_base_per_key() {
        let mut base = sample();
        base.vars
            .insert("region".into(), toml::Value::String("eu".into()));
        base.vars
            .insert("tier".into(), toml::Value::String("base".into()));
        let overlay: ManifestOverlay =
            toml::from_str("[vars]\nregion = \"us\"\nextra = true\n").unwrap();
        base.apply_overlay(overlay);
        // overlay wins for `region`, base-only `tier` survives, overlay adds `extra`.
        assert_eq!(base.vars["region"], toml::Value::String("us".into()));
        assert_eq!(base.vars["tier"], toml::Value::String("base".into()));
        assert_eq!(base.vars["extra"], toml::Value::Boolean(true));
    }
}
