//! Wire types for the daemon ↔ stdio-MCP-bridge unix socket protocol.
//!
//! Same shape as `damocles-daemon`'s `DaemonRequest`/`DaemonResponse`
//! (which this is forked from in spirit). Each request is a single
//! JSON line; each response is a single JSON line back. The stdio MCP
//! bridge holds a fresh connection per tool call — claude's tool
//! lifecycle is shorter than a persistent matrix-sdk Client wants to
//! live, so the daemon stays alive and the MCP reconnects per call.

use serde::{Deserialize, Serialize};

/// Request from the stdio MCP bridge to the daemon. The MCP bridge
/// owns the on-wire shape claude sees; this enum is the internal
/// shape the daemon dispatches over.
#[derive(Debug, Serialize, Deserialize)]
#[serde(tag = "method")]
pub enum DaemonRequest {
    /// Post a plain-text or markdown message to a room. `room` accepts
    /// either a matrix room id (`!abc:server`) or a canonical alias
    /// (`#name:server`); the daemon resolves aliases server-side.
    #[serde(rename = "send_message")]
    SendMessage { room: String, body: String },

    /// Open (or reuse) a DM with `user_id` and post `body`. Creates
    /// the DM room if one doesn't already exist between this agent
    /// and the user.
    #[serde(rename = "send_dm")]
    SendDm { user_id: String, body: String },

    /// React to a specific event with an emoji `key`. Matrix-spec
    /// `m.reaction` annotation.
    #[serde(rename = "send_reaction")]
    SendReaction {
        room: String,
        event_id: String,
        key: String,
    },

    /// Reply to `event_id` in `room` with `body` as a threaded reply.
    /// Sets the `m.in_reply_to` relation so matrix clients render the
    /// thread.
    #[serde(rename = "send_reply")]
    SendReply {
        room: String,
        event_id: String,
        body: String,
    },

    /// Mark `event_id` (in `room`) as read for this agent. Sends a
    /// read receipt; bumps the room's "unread" indicator down on
    /// matrix clients (and for other agents).
    #[serde(rename = "mark_read")]
    MarkRead { room: String, event_id: String },

    /// List rooms the agent has joined. Returns each room's id +
    /// canonical alias (when present) + name + member count.
    #[serde(rename = "list_rooms")]
    ListRooms,

    /// List the members of a room. Each entry carries the matrix
    /// user id + the resolved display name (when set).
    #[serde(rename = "list_room_members")]
    ListRoomMembers { room: String },

    /// Read the last `limit` events from a room's timeline. Caller
    /// gets each event's id, sender, `server_ts`, type, and body (best-
    /// effort plain-text extraction from `m.text` / `m.notice` etc.).
    #[serde(rename = "read_room")]
    ReadRoom { room: String, limit: Option<usize> },

    /// List rooms this agent has been invited to but not yet joined.
    /// Returns each room's id, canonical alias (when present), and
    /// display name.
    #[serde(rename = "list_invites")]
    ListInvites,

    /// Join a room by id (`!abc:server`) or alias (`#name:server`).
    /// Accepts a pending invite if one exists; also joins public rooms
    /// the agent hasn't been explicitly invited to. After joining the
    /// room will appear in `list_rooms`.
    #[serde(rename = "join_room")]
    JoinRoom { room: String },

    /// Return the count of rooms with unread notifications. Used by
    /// the harness `get_loose_ends` to surface unread matrix activity
    /// without exposing message content.
    #[serde(rename = "unread_count")]
    UnreadCount,

    /// Return per-room unread summaries. For rooms with exactly one
    /// unread notification, attempts to include the sender + truncated
    /// body; rooms with multiple unreads carry only the count. Used by
    /// `get_loose_ends` and the wake-signal formatter.
    #[serde(rename = "unread_summary")]
    UnreadSummary,

    /// Liveness probe — fast "are you up?" round-trip that doesn't
    /// touch matrix-sdk. Not used by the in-tree stdio MCP bridge
    /// (which surfaces a daemon-down condition as a normal tool-call
    /// connect error); reserved for external clients that want an
    /// explicit health check without doing real work.
    #[serde(rename = "ping")]
    Ping,
}

/// One entry in the [`DaemonRequest::UnreadSummary`] response payload.
#[derive(Debug, Serialize, Deserialize)]
pub struct RoomUnread {
    /// Canonical alias (`#name:server`) or room id (`!id:server`).
    pub label: String,
    /// Server-side push-notification count for this room. Always ≥ 1.
    pub count: u32,
    /// Truncated body of the last message in the room. Present only when
    /// `count == 1` and the fetch succeeded; absent otherwise.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub last_body: Option<String>,
    /// Sender of the last message (`@user:server`). Present when
    /// `last_body` is present.
    #[serde(skip_serializing_if = "Option::is_none")]
    pub last_sender: Option<String>,
}

/// Response shape: `ok` carries the payload (any JSON; the MCP bridge
/// passes it back to claude as the tool result), `error` carries a
/// human-readable error string.
#[derive(Debug, Serialize, Deserialize)]
#[serde(tag = "kind", rename_all = "snake_case")]
pub enum DaemonResponse {
    Ok { payload: serde_json::Value },
    Error { message: String },
}

impl DaemonResponse {
    /// Convenience: build an Ok response from any serializable value.
    /// Serialisation failure (impossible for the small handler structs
    /// we use, but the API is generic) surfaces as a structured
    /// `{"serialise_error": "..."}` payload so callers see WHY the
    /// data is missing instead of a silent `null`.
    pub fn ok<T: Serialize>(payload: &T) -> Self {
        let payload = serde_json::to_value(payload)
            .unwrap_or_else(|e| serde_json::json!({ "serialise_error": e.to_string() }));
        Self::Ok { payload }
    }

    /// Convenience: build an Error response from any `Display` value.
    pub fn error(msg: impl std::fmt::Display) -> Self {
        Self::Error {
            message: msg.to_string(),
        }
    }
}