//! Message drafts — maps to `message_draft` table.
//!
//! Stores unsent messages so they survive browser refreshes and sync across
//! the user's connected devices. One draft per (channel, user, optional thread).
//! Drafts are upserted on every keystroke debounce and deleted on send.

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

/// A user's unsent message draft in a channel.
#[derive(Debug, Clone, Serialize, Deserialize, sqlx::FromRow)]
pub struct MessageDraft {
    pub id: Uuid,
    pub channel_id: Uuid,
    pub user_id: Uuid,
    /// Thread the draft belongs to (NULL = top-level).
    pub thread_id: Option<Uuid>,
    /// Message this draft is replying to (NULL = new message).
    pub reply_to_message_id: Option<Uuid>,
    /// Plain text or markdown body.
    pub body: String,
    /// Extensible metadata (attachments to be uploaded, etc.).
    pub metadata: Option<serde_json::Value>,
    pub created_at: DateTime<Utc>,
    pub updated_at: DateTime<Utc>,
}

/// Input for upserting a draft (sent from client on debounced keystroke).
#[derive(Debug, Clone, Serialize, Deserialize)]
pub struct DraftUpsertInput {
    pub channel_id: Uuid,
    pub thread_id: Option<Uuid>,
    pub reply_to_message_id: Option<Uuid>,
    pub body: String,
    pub metadata: Option<serde_json::Value>,
}

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

    #[test]
    fn test_draft_upsert_input_serialize() {
        let input = DraftUpsertInput {
            channel_id: Uuid::now_v7(),
            thread_id: None,
            reply_to_message_id: None,
            body: "hello, this is a draft".to_string(),
            metadata: None,
        };

        let json = serde_json::to_value(&input).unwrap();
        assert_eq!(json["body"], "hello, this is a draft");
        assert!(json["thread_id"].is_null());
    }

    #[test]
    fn test_draft_serialize() {
        let draft = MessageDraft {
            id: Uuid::now_v7(),
            channel_id: Uuid::now_v7(),
            user_id: Uuid::now_v7(),
            thread_id: Some(Uuid::now_v7()),
            reply_to_message_id: None,
            body: "draft body".to_string(),
            metadata: Some(serde_json::json!({"pending_attachments": []})),
            created_at: Utc::now(),
            updated_at: Utc::now(),
        };

        let json = serde_json::to_value(&draft).unwrap();
        assert_eq!(json["body"], "draft body");
        assert!(json["thread_id"].is_string());
        assert!(json["metadata"]["pending_attachments"].is_array());
    }
}