use anyhow::Result;
use async_trait::async_trait;
use chrono::Utc;
use k_ap::{
    ActorRepository, FollowRepository, Follower, FollowerStatus, FollowingStatus, RemoteActor,
};
use sqlx::Row;

use super::{
    SqliteFederationRepository, datetime_to_str, remote_actor_from_row, status_to_str,
    str_to_status,
};

#[async_trait]
impl FollowRepository for SqliteFederationRepository {
    async fn add_follower(
        &self,
        local_user_id: uuid::Uuid,
        remote_actor_url: &str,
        status: FollowerStatus,
        follow_activity_id: &str,
    ) -> Result<()> {
        let uid = local_user_id.to_string();
        let status_str = status_to_str(&status);
        let now = Utc::now().naive_utc();
        let created_at = datetime_to_str(&now);
        sqlx::query(
            "INSERT INTO ap_followers (local_user_id, remote_actor_url, status, created_at, follow_activity_id)
             VALUES (?1, ?2, ?3, ?4, ?5)
             ON CONFLICT(local_user_id, remote_actor_url) DO UPDATE SET
                 status = excluded.status,
                 follow_activity_id = excluded.follow_activity_id",
        )
        .bind(&uid)
        .bind(remote_actor_url)
        .bind(status_str)
        .bind(&created_at)
        .bind(follow_activity_id)
        .execute(&self.pool)
        .await?;
        Ok(())
    }

    async fn get_follower_follow_activity_id(
        &self,
        local_user_id: uuid::Uuid,
        remote_actor_url: &str,
    ) -> Result<Option<String>> {
        let uid = local_user_id.to_string();
        let row: Option<Option<String>> = sqlx::query_scalar(
            "SELECT follow_activity_id FROM ap_followers WHERE local_user_id = ? AND remote_actor_url = ?",
        )
        .bind(&uid)
        .bind(remote_actor_url)
        .fetch_optional(&self.pool)
        .await?;
        Ok(row.flatten())
    }

    async fn remove_follower(
        &self,
        local_user_id: uuid::Uuid,
        remote_actor_url: &str,
    ) -> Result<()> {
        let uid = local_user_id.to_string();
        sqlx::query("DELETE FROM ap_followers WHERE local_user_id = ? AND remote_actor_url = ?")
            .bind(&uid)
            .bind(remote_actor_url)
            .execute(&self.pool)
            .await?;
        Ok(())
    }

    async fn get_followers(&self, local_user_id: uuid::Uuid) -> Result<Vec<Follower>> {
        let uid = local_user_id.to_string();
        let rows = sqlx::query(
            "SELECT f.remote_actor_url, f.status,
                    a.handle, a.inbox_url, a.shared_inbox_url, a.display_name, a.avatar_url,
                    a.outbox_url, a.bio, a.banner_url, a.followers_url, a.following_url, a.also_known_as, a.fetched_at
             FROM ap_followers f
             LEFT JOIN ap_remote_actors a ON a.url = f.remote_actor_url
             WHERE f.local_user_id = ?",
        )
        .bind(&uid)
        .fetch_all(&self.pool)
        .await?;
        Ok(rows
            .iter()
            .map(|row| {
                let status_str: String = row.get("status");
                Follower {
                    actor: remote_actor_from_row(row, "remote_actor_url"),
                    status: str_to_status(&status_str),
                }
            })
            .collect())
    }

    async fn get_followers_page(
        &self,
        local_user_id: uuid::Uuid,
        offset: u32,
        limit: usize,
    ) -> Result<Vec<Follower>> {
        let uid = local_user_id.to_string();
        let rows = sqlx::query(
            "SELECT f.remote_actor_url, f.status,
                    a.handle, a.inbox_url, a.shared_inbox_url, a.display_name, a.avatar_url,
                    a.outbox_url, a.bio, a.banner_url, a.followers_url, a.following_url, a.also_known_as, a.fetched_at
             FROM ap_followers f
             LEFT JOIN ap_remote_actors a ON a.url = f.remote_actor_url
             WHERE f.local_user_id = ? AND f.status = 'accepted'
             ORDER BY f.created_at ASC LIMIT ? OFFSET ?",
        )
        .bind(&uid)
        .bind(limit as i64)
        .bind(offset as i64)
        .fetch_all(&self.pool)
        .await?;
        Ok(rows
            .iter()
            .map(|row| {
                let status_str: String = row.get("status");
                Follower {
                    actor: remote_actor_from_row(row, "remote_actor_url"),
                    status: str_to_status(&status_str),
                }
            })
            .collect())
    }

    async fn count_followers(&self, local_user_id: uuid::Uuid) -> Result<usize> {
        let uid = local_user_id.to_string();
        let count: i64 = sqlx::query_scalar(
            "SELECT COUNT(*) FROM ap_followers WHERE local_user_id = ? AND status = 'accepted'",
        )
        .bind(&uid)
        .fetch_one(&self.pool)
        .await?;
        Ok(count as usize)
    }

    async fn update_follower_status(
        &self,
        local_user_id: uuid::Uuid,
        remote_actor_url: &str,
        status: FollowerStatus,
    ) -> Result<()> {
        let uid = local_user_id.to_string();
        let status_str = status_to_str(&status);
        let result = sqlx::query(
            "UPDATE ap_followers SET status = ? WHERE local_user_id = ? AND remote_actor_url = ?",
        )
        .bind(status_str)
        .bind(&uid)
        .bind(remote_actor_url)
        .execute(&self.pool)
        .await?;
        if result.rows_affected() == 0 {
            tracing::warn!(local_user_id = %local_user_id, remote_actor_url, "update_follower_status: no row found");
        }
        Ok(())
    }

    async fn get_pending_followers(&self, local_user_id: uuid::Uuid) -> Result<Vec<RemoteActor>> {
        let uid = local_user_id.to_string();
        let rows = sqlx::query(
            "SELECT f.remote_actor_url,
                    a.handle, a.inbox_url, a.shared_inbox_url, a.display_name, a.avatar_url,
                    a.outbox_url, a.bio, a.banner_url, a.followers_url, a.following_url, a.also_known_as, a.fetched_at
             FROM ap_followers f
             LEFT JOIN ap_remote_actors a ON a.url = f.remote_actor_url
             WHERE f.local_user_id = ? AND f.status = 'pending'",
        ).bind(&uid).fetch_all(&self.pool).await?;
        Ok(rows
            .iter()
            .map(|row| remote_actor_from_row(row, "remote_actor_url"))
            .collect())
    }

    async fn get_accepted_follower_inboxes(
        &self,
        local_user_id: uuid::Uuid,
    ) -> Result<Vec<String>> {
        let uid = local_user_id.to_string();
        let rows = sqlx::query(
            "SELECT DISTINCT COALESCE(a.shared_inbox_url, a.inbox_url) as inbox
             FROM ap_followers f
             INNER JOIN ap_remote_actors a ON a.url = f.remote_actor_url
             WHERE f.local_user_id = ? AND f.status = 'accepted'
               AND f.remote_actor_url NOT IN (
                   SELECT remote_actor_url FROM blocked_actors WHERE local_user_id = ?
               )",
        )
        .bind(&uid)
        .bind(&uid)
        .fetch_all(&self.pool)
        .await?;
        Ok(rows
            .iter()
            .filter_map(|r| r.try_get::<String, _>("inbox").ok())
            .collect())
    }

    async fn count_accepted_followers(&self, local_user_id: uuid::Uuid) -> Result<usize> {
        let uid = local_user_id.to_string();
        let count: i64 = sqlx::query_scalar(
            "SELECT COUNT(*) FROM ap_followers WHERE local_user_id = ? AND status = 'accepted'",
        )
        .bind(&uid)
        .fetch_one(&self.pool)
        .await?;
        Ok(count as usize)
    }

    async fn get_accepted_followers_page(
        &self,
        local_user_id: uuid::Uuid,
        offset: u32,
        limit: usize,
    ) -> Result<Vec<RemoteActor>> {
        let uid = local_user_id.to_string();
        let rows = sqlx::query(
            "SELECT f.remote_actor_url,
                    a.handle, a.inbox_url, a.shared_inbox_url, a.display_name, a.avatar_url,
                    a.outbox_url, a.bio, a.banner_url, a.followers_url, a.following_url, a.also_known_as, a.fetched_at
             FROM ap_followers f
             LEFT JOIN ap_remote_actors a ON a.url = f.remote_actor_url
             WHERE f.local_user_id = ? AND f.status = 'accepted'
             ORDER BY f.created_at ASC LIMIT ? OFFSET ?",
        ).bind(&uid).bind(limit as i64).bind(offset as i64).fetch_all(&self.pool).await?;
        Ok(rows
            .iter()
            .map(|row| remote_actor_from_row(row, "remote_actor_url"))
            .collect())
    }

    async fn add_following(
        &self,
        local_user_id: uuid::Uuid,
        actor: RemoteActor,
        follow_activity_id: &str,
    ) -> Result<()> {
        let uid = local_user_id.to_string();
        let now = Utc::now().naive_utc();
        let created_at = datetime_to_str(&now);
        ActorRepository::upsert_remote_actor(self, actor.clone()).await?;
        sqlx::query(
            "INSERT OR IGNORE INTO ap_following (local_user_id, remote_actor_url, follow_activity_id, created_at)
             VALUES (?, ?, ?, ?)",
        ).bind(&uid).bind(&actor.url).bind(follow_activity_id).bind(&created_at).execute(&self.pool).await?;
        Ok(())
    }

    async fn get_follow_activity_id(
        &self,
        local_user_id: uuid::Uuid,
        remote_actor_url: &str,
    ) -> Result<Option<String>> {
        let uid = local_user_id.to_string();
        let row: Option<Option<String>> = sqlx::query_scalar(
            "SELECT follow_activity_id FROM ap_following WHERE local_user_id = ? AND remote_actor_url = ?",
        ).bind(&uid).bind(remote_actor_url).fetch_optional(&self.pool).await?;
        Ok(row.flatten())
    }

    async fn remove_following(&self, local_user_id: uuid::Uuid, actor_url: &str) -> Result<()> {
        let uid = local_user_id.to_string();
        sqlx::query("DELETE FROM ap_following WHERE local_user_id = ? AND remote_actor_url = ?")
            .bind(&uid)
            .bind(actor_url)
            .execute(&self.pool)
            .await?;
        Ok(())
    }

    async fn get_following(&self, local_user_id: uuid::Uuid) -> Result<Vec<RemoteActor>> {
        let uid = local_user_id.to_string();
        let rows = sqlx::query(
            "SELECT a.url, a.handle, a.inbox_url, a.shared_inbox_url, a.display_name, a.avatar_url,
                    a.outbox_url, a.bio, a.banner_url, a.followers_url, a.following_url, a.also_known_as, a.fetched_at
             FROM ap_following f
             INNER JOIN ap_remote_actors a ON a.url = f.remote_actor_url
             WHERE f.local_user_id = ? AND f.status = 'accepted'",
        ).bind(&uid).fetch_all(&self.pool).await?;
        Ok(rows
            .iter()
            .map(|row| remote_actor_from_row(row, "url"))
            .collect())
    }

    async fn count_following(&self, local_user_id: uuid::Uuid) -> Result<usize> {
        let uid = local_user_id.to_string();
        let count: i64 = sqlx::query_scalar(
            "SELECT COUNT(*) FROM ap_following WHERE local_user_id = ? AND status = 'accepted'",
        )
        .bind(&uid)
        .fetch_one(&self.pool)
        .await?;
        Ok(count as usize)
    }

    async fn get_following_page(
        &self,
        local_user_id: uuid::Uuid,
        offset: u32,
        limit: usize,
    ) -> Result<Vec<RemoteActor>> {
        let uid = local_user_id.to_string();
        let rows = sqlx::query(
            "SELECT a.url, a.handle, a.inbox_url, a.shared_inbox_url, a.display_name, a.avatar_url,
                    a.outbox_url, a.bio, a.banner_url, a.followers_url, a.following_url, a.also_known_as, a.fetched_at
             FROM ap_following f
             INNER JOIN ap_remote_actors a ON a.url = f.remote_actor_url
             WHERE f.local_user_id = ? AND f.status = 'accepted'
             ORDER BY f.created_at ASC LIMIT ? OFFSET ?",
        ).bind(&uid).bind(limit as i64).bind(offset as i64).fetch_all(&self.pool).await?;
        Ok(rows
            .iter()
            .map(|row| remote_actor_from_row(row, "url"))
            .collect())
    }

    async fn update_following_status(
        &self,
        local_user_id: uuid::Uuid,
        remote_actor_url: &str,
        status: FollowingStatus,
    ) -> Result<()> {
        let uid = local_user_id.to_string();
        let status_str = match status {
            FollowingStatus::Pending => "pending",
            FollowingStatus::Accepted => "accepted",
        };
        let result = sqlx::query(
            "UPDATE ap_following SET status = ? WHERE local_user_id = ? AND remote_actor_url = ?",
        )
        .bind(status_str)
        .bind(&uid)
        .bind(remote_actor_url)
        .execute(&self.pool)
        .await?;
        if result.rows_affected() == 0 {
            tracing::warn!(local_user_id = %local_user_id, remote_actor_url, "update_following_status: no row found");
        }
        Ok(())
    }

    async fn get_following_outbox_url(
        &self,
        local_user_id: uuid::Uuid,
        remote_actor_url: &str,
    ) -> Result<Option<String>> {
        let uid = local_user_id.to_string();
        let row: Option<Option<String>> = sqlx::query_scalar(
            "SELECT a.outbox_url
             FROM ap_following f
             INNER JOIN ap_remote_actors a ON a.url = f.remote_actor_url
             WHERE f.local_user_id = ? AND f.remote_actor_url = ?",
        )
        .bind(&uid)
        .bind(remote_actor_url)
        .fetch_optional(&self.pool)
        .await?;
        Ok(row.flatten())
    }

    async fn migrate_follower_actor(
        &self,
        old_actor_url: &str,
        new_actor_url: &str,
    ) -> Result<Vec<uuid::Uuid>> {
        let candidates: Vec<String> = sqlx::query_scalar(
            "SELECT local_user_id FROM ap_following
             WHERE remote_actor_url = ?1
               AND local_user_id NOT IN (
                   SELECT local_user_id FROM ap_following WHERE remote_actor_url = ?2
               )",
        )
        .bind(old_actor_url)
        .bind(new_actor_url)
        .fetch_all(&self.pool)
        .await?;

        if candidates.is_empty() {
            return Ok(vec![]);
        }

        sqlx::query(
            "UPDATE ap_following SET remote_actor_url = ?1
             WHERE remote_actor_url = ?2
               AND local_user_id NOT IN (
                   SELECT local_user_id FROM ap_following WHERE remote_actor_url = ?1
               )",
        )
        .bind(new_actor_url)
        .bind(old_actor_url)
        .execute(&self.pool)
        .await?;

        candidates
            .into_iter()
            .map(|s| uuid::Uuid::parse_str(&s).map_err(|e| anyhow::anyhow!(e)))
            .collect()
    }
}