use chrono::{DateTime, Utc};
use serde::{Deserialize, Serialize};

use crate::{AppId, ScriptId, ScriptSandbox};

/// Semantic role of a script (v1.1.3).
///
/// `Endpoint` scripts have an executable entry point — they bind to HTTP
/// routes and act as trigger handlers. `Module` scripts are libraries of
/// `fn`/`const` declarations imported by other scripts via Rhai's
/// `import "<name>" as <alias>;` syntax. Modules cannot be invoked
/// directly: route binding and trigger creation reject `Module` targets.
///
/// Serialized as `"endpoint"` / `"module"` so the wire shape is the
/// same string the SQL `CHECK (kind IN ('endpoint','module'))`
/// constraint enforces.
#[derive(Debug, Clone, Copy, Default, PartialEq, Eq, Hash, Serialize, Deserialize)]
#[serde(rename_all = "lowercase")]
pub enum ScriptKind {
    #[default]
    Endpoint,
    Module,
}

impl ScriptKind {
    /// Wire / SQL representation. Inverse of `parse_str`.
    #[must_use]
    pub fn as_str(self) -> &'static str {
        match self {
            Self::Endpoint => "endpoint",
            Self::Module => "module",
        }
    }

    /// Parse the canonical wire / SQL form. Returns `None` for any
    /// other input; callers map that to a 400 / `ValidationError`.
    /// Named `parse_str` (not `from_str`) to dodge the
    /// `std::str::FromStr` lint without taking on the trait's
    /// `Result<Self, Self::Err>` shape that this caller doesn't need.
    #[must_use]
    pub fn parse_str(s: &str) -> Option<Self> {
        match s {
            "endpoint" => Some(Self::Endpoint),
            "module" => Some(Self::Module),
            _ => None,
        }
    }
}

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

    #[test]
    fn default_is_endpoint() {
        assert_eq!(ScriptKind::default(), ScriptKind::Endpoint);
    }

    #[test]
    fn round_trips_through_serde_lowercase() {
        assert_eq!(
            serde_json::to_string(&ScriptKind::Endpoint).unwrap(),
            "\"endpoint\""
        );
        assert_eq!(
            serde_json::to_string(&ScriptKind::Module).unwrap(),
            "\"module\""
        );
        assert_eq!(
            serde_json::from_str::<ScriptKind>("\"endpoint\"").unwrap(),
            ScriptKind::Endpoint
        );
        assert_eq!(
            serde_json::from_str::<ScriptKind>("\"module\"").unwrap(),
            ScriptKind::Module
        );
    }

    #[test]
    fn parse_str_round_trip() {
        for k in [ScriptKind::Endpoint, ScriptKind::Module] {
            assert_eq!(ScriptKind::parse_str(k.as_str()), Some(k));
        }
        assert_eq!(ScriptKind::parse_str("invalid"), None);
        assert_eq!(ScriptKind::parse_str(""), None);
    }
}

/// A user-uploaded Rhai script and its execution configuration.
///
/// This is the canonical representation that flows between manager (storage),
/// orchestrator (dispatch), and executor (run). It must stay serializable
/// because in cluster mode it crosses process boundaries on every invocation.
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct Script {
    pub id: ScriptId,
    /// Owning app. Set on create, immutable thereafter — a "move to
    /// another app" is a copy+delete, not an in-place edit (snapshot
    /// semantics — see blueprint §11.5).
    pub app_id: AppId,
    pub name: String,
    pub description: Option<String>,
    pub version: i32,
    pub source: String,

    /// `Endpoint` (default; the only kind v1.0 through v1.1.2 supported)
    /// or `Module` (v1.1.3 — imported by other scripts, never bound
    /// directly to a route or trigger).
    #[serde(default)]
    pub kind: ScriptKind,

    pub timeout_seconds: u32,

    /// Per-script overrides for Rhai sandbox limits. Empty = platform
    /// defaults. Values are admin-ceiling-clamped at write time.
    #[serde(default)]
    pub sandbox: ScriptSandbox,

    /// **v1.3+ advisory only.** Real heap limits require OS-level
    /// isolation (cgroups, process limits) which lands with cluster-mode
    /// executor sandboxing. The field stays in the schema so we don't
    /// have to add it back when that's built.
    pub memory_limit_mb: u32,

    /// Three-state lifecycle (§4.3): `false` means deployed-but-inert — the
    /// script is not invocable (route 404s, trigger doesn't fire) but stays
    /// as desired state (not pruned). Defaults `true`.
    #[serde(default = "crate::default_true")]
    pub enabled: bool,

    pub created_at: DateTime<Utc>,
    pub updated_at: DateTime<Utc>,
}