//! Notification CRUD operations on `MessageRepo`.

use chrono::Utc;
use uuid::Uuid;

use crate::ImksResult;
use crate::models::message_notification::MessageNotification;

use super::message_repo::MessageRepo;
use super::pagination::{CursorPage, clamp_limit};

impl MessageRepo {
    /// Create a notification for a user triggered by a message.
    pub async fn create_notification(
        &self,
        message_id: Uuid,
        channel_id: Uuid,
        user_id: Uuid,
        reason: &str,
        delivery_channel: Option<&str>,
    ) -> ImksResult<MessageNotification> {
        let id = Uuid::now_v7();
        let now = Utc::now();

        sqlx::query_as::<_, MessageNotification>(
            r#"
            INSERT INTO message_notification (
                id, message_id, channel_id, user_id, reason, status, delivery_channel, created_at
            ) VALUES ($1, $2, $3, $4, $5, 'pending', $6, $7)
            RETURNING *
            "#,
        )
        .bind(id)
        .bind(message_id)
        .bind(channel_id)
        .bind(user_id)
        .bind(reason)
        .bind(delivery_channel)
        .bind(now)
        .fetch_one(self.pool())
        .await
        .map_err(Into::into)
    }

    /// Mark a notification as read.
    pub async fn mark_notification_read(&self, notification_id: Uuid) -> ImksResult<()> {
        let now = Utc::now();
        sqlx::query(
            r#"
            UPDATE message_notification
            SET status = 'read', read_at = $1
            WHERE id = $2
            "#,
        )
        .bind(now)
        .bind(notification_id)
        .execute(self.pool())
        .await?;

        Ok(())
    }

    /// Mark all of a user's notifications as read.
    pub async fn mark_all_notifications_read(&self, user_id: Uuid) -> ImksResult<u64> {
        let now = Utc::now();
        let result = sqlx::query(
            r#"
            UPDATE message_notification
            SET status = 'read', read_at = $1
            WHERE user_id = $2 AND status != 'read'
            "#,
        )
        .bind(now)
        .bind(user_id)
        .execute(self.pool())
        .await?;

        Ok(result.rows_affected())
    }

    /// List notifications for a user, newest first.
    pub async fn list_notifications(
        &self,
        user_id: Uuid,
        before: Option<Uuid>,
        limit: Option<i64>,
    ) -> ImksResult<CursorPage<MessageNotification>> {
        let effective_limit = clamp_limit(limit);
        let fetch_limit = effective_limit + 1;

        let rows = match before {
            Some(cursor) => {
                sqlx::query_as::<_, MessageNotification>(
                    r#"
                    SELECT * FROM message_notification
                    WHERE user_id = $1 AND id < $2
                    ORDER BY id DESC
                    LIMIT $3
                    "#,
                )
                .bind(user_id)
                .bind(cursor)
                .bind(fetch_limit)
                .fetch_all(self.pool())
                .await?
            }
            None => {
                sqlx::query_as::<_, MessageNotification>(
                    r#"
                    SELECT * FROM message_notification
                    WHERE user_id = $1
                    ORDER BY id DESC
                    LIMIT $2
                    "#,
                )
                .bind(user_id)
                .bind(fetch_limit)
                .fetch_all(self.pool())
                .await?
            }
        };

        Ok(CursorPage::from_raw(rows, effective_limit, |n| n.id))
    }

    /// Get unread notification count for a user.
    pub async fn get_unread_notification_count(&self, user_id: Uuid) -> ImksResult<i64> {
        let count: i64 = sqlx::query_scalar(
            r#"
            SELECT COUNT(*)::BIGINT FROM message_notification
            WHERE user_id = $1 AND status = 'pending'
            "#,
        )
        .bind(user_id)
        .fetch_one(self.pool())
        .await?;

        Ok(count)
    }
}