//! Reaction event handlers on `MessageService`.
//!
//! Toggle semantics: sending the same reaction again removes it.

use std::sync::Arc;

use uuid::Uuid;

use crate::ImksError;
use crate::socket::socket::Socket;

use super::message::MessageService;

impl MessageService {
    /// Handle `reaction:add` — toggle (add or remove) a reaction, then broadcast.
    pub async fn toggle_reaction(
        &self,
        socket: Arc<Socket>,
        data: &serde_json::Value,
    ) -> crate::ImksResult<()> {
        let user_id = self.user_id(&socket)?;
        let (message_id, content) = self.parse_reaction_payload(data)?;
        let message = self
            .repo
            .get(message_id)
            .await?
            .ok_or_else(|| ImksError::NotFound(format!("message {message_id}")))?;
        let channel_id = message.channel_id;
        let channel_id_str = channel_id.to_string();
        let user_id_str = user_id.to_string();

        self.ensure_readable(&channel_id_str, &user_id_str).await?;
        self.ensure_member(&channel_id_str, &user_id_str).await?;

        let action = if self
            .repo
            .add_reaction(message_id, channel_id, user_id, &content)
            .await?
            .is_some()
        {
            tracing::info!(%message_id, %user_id, %content, "Reaction added");
            "add"
        } else {
            self.repo
                .remove_reaction(message_id, user_id, &content)
                .await?;
            tracing::info!(%message_id, %user_id, %content, "Reaction removed");
            "remove"
        };

        if let Some(ns) = self.namespaces.get_namespace(&socket.namespace) {
            ns.emit_to_room(
                &channel_id.to_string(),
                "reaction:updated",
                serde_json::json!({
                    "message_id": message_id.to_string(),
                    "channel_id": channel_id.to_string(),
                    "user_id": user_id.to_string(),
                    "content": content,
                    "action": action,
                }),
            )
            .await;
        }
        Ok(())
    }

    /// Handle `reaction:remove` — explicitly remove a reaction.
    pub async fn remove_reaction(
        &self,
        socket: Arc<Socket>,
        data: &serde_json::Value,
    ) -> crate::ImksResult<()> {
        let user_id = self.user_id(&socket)?;
        let (message_id, content) = self.parse_reaction_payload(data)?;
        let message = self
            .repo
            .get(message_id)
            .await?
            .ok_or_else(|| ImksError::NotFound(format!("message {message_id}")))?;
        let channel_id = message.channel_id;
        let channel_id_str = channel_id.to_string();
        let user_id_str = user_id.to_string();

        self.ensure_readable(&channel_id_str, &user_id_str).await?;
        self.ensure_member(&channel_id_str, &user_id_str).await?;

        self.repo
            .remove_reaction(message_id, user_id, &content)
            .await?;

        if let Some(ns) = self.namespaces.get_namespace(&socket.namespace) {
            ns.emit_to_room(
                &channel_id.to_string(),
                "reaction:updated",
                serde_json::json!({
                    "message_id": message_id.to_string(),
                    "channel_id": channel_id.to_string(),
                    "user_id": user_id.to_string(),
                    "content": content,
                    "action": "remove",
                }),
            )
            .await;
        }
        Ok(())
    }

    fn parse_reaction_payload(
        &self,
        data: &serde_json::Value,
    ) -> crate::ImksResult<(Uuid, String)> {
        let arr = data
            .as_array()
            .and_then(|a| a.first())
            .ok_or_else(|| ImksError::InvalidInput("Expected [payload] array".into()))?;

        let content: String = Self::parse_field(arr, "content")?;
        if content.trim().is_empty() {
            return Err(ImksError::InvalidInput(
                "Reaction content cannot be empty".into(),
            ));
        }

        Ok((Self::parse_field(arr, "message_id")?, content))
    }
}