use async_trait::async_trait;
use chrono::{DateTime, Utc};
use sqlx::PgPool;
use url::Url;

use domain::{
    errors::DomainError,
    models::thought::{Thought, Visibility},
    ports::{ActivityPubRepository, OutboxEntry},
    value_objects::{Content, ThoughtId, UserId, Username},
};

pub struct PgActivityPubRepository {
    pool: PgPool,
}

impl PgActivityPubRepository {
    pub fn new(pool: PgPool) -> Self {
        Self { pool }
    }
}

#[async_trait]
impl ActivityPubRepository for PgActivityPubRepository {
    async fn outbox_entries_for_actor(&self, user_id: &UserId) -> Result<Vec<OutboxEntry>, DomainError> {
        #[derive(sqlx::FromRow)]
        struct Row {
            id: uuid::Uuid,
            user_id: uuid::Uuid,
            content: String,
            created_at: DateTime<Utc>,
            in_reply_to_id: Option<uuid::Uuid>,
            content_warning: Option<String>,
            sensitive: bool,
            username: String,
            updated_at: Option<DateTime<Utc>>,
        }
        sqlx::query_as::<_, Row>(
            "SELECT t.id, t.user_id, t.content, t.created_at, t.in_reply_to_id, t.content_warning, t.sensitive, u.username, t.updated_at
             FROM thoughts t JOIN users u ON u.id=t.user_id
             WHERE t.user_id=$1 AND t.local=true AND t.visibility='public'
             ORDER BY t.created_at DESC",
        )
        .bind(user_id.as_uuid())
        .fetch_all(&self.pool)
        .await
        .map_err(|e| DomainError::Internal(e.to_string()))
        .map(|rows| {
            rows.into_iter()
                .map(|r| OutboxEntry {
                    thought: Thought {
                        id: ThoughtId::from_uuid(r.id),
                        user_id: UserId::from_uuid(r.user_id),
                        content: Content::new_remote(r.content),
                        in_reply_to_id: r.in_reply_to_id.map(ThoughtId::from_uuid),
                        in_reply_to_url: None,
                        ap_id: None,
                        visibility: Visibility::Public,
                        content_warning: r.content_warning,
                        sensitive: r.sensitive,
                        local: true,
                        created_at: r.created_at,
                        updated_at: r.updated_at,
                    },
                    author_username: Username::from_trusted(r.username),
                })
                .collect()
        })
    }

    async fn outbox_page_for_actor(
        &self,
        user_id: &UserId,
        before: Option<DateTime<Utc>>,
        limit: usize,
    ) -> Result<Vec<OutboxEntry>, DomainError> {
        #[derive(sqlx::FromRow)]
        struct Row {
            id: uuid::Uuid,
            user_id: uuid::Uuid,
            content: String,
            created_at: DateTime<Utc>,
            in_reply_to_id: Option<uuid::Uuid>,
            content_warning: Option<String>,
            sensitive: bool,
            username: String,
            updated_at: Option<DateTime<Utc>>,
        }
        let rows = if let Some(before) = before {
            sqlx::query_as::<_, Row>(
                "SELECT t.id, t.user_id, t.content, t.created_at, t.in_reply_to_id, t.content_warning, t.sensitive, u.username, t.updated_at
                 FROM thoughts t JOIN users u ON u.id=t.user_id
                 WHERE t.user_id=$1 AND t.local=true AND t.visibility='public' AND t.created_at < $2
                 ORDER BY t.created_at DESC LIMIT $3",
            )
            .bind(user_id.as_uuid())
            .bind(before)
            .bind(limit as i64)
            .fetch_all(&self.pool)
            .await
        } else {
            sqlx::query_as::<_, Row>(
                "SELECT t.id, t.user_id, t.content, t.created_at, t.in_reply_to_id, t.content_warning, t.sensitive, u.username, t.updated_at
                 FROM thoughts t JOIN users u ON u.id=t.user_id
                 WHERE t.user_id=$1 AND t.local=true AND t.visibility='public'
                 ORDER BY t.created_at DESC LIMIT $2",
            )
            .bind(user_id.as_uuid())
            .bind(limit as i64)
            .fetch_all(&self.pool)
            .await
        }
        .map_err(|e| DomainError::Internal(e.to_string()))?;

        Ok(rows
            .into_iter()
            .map(|r| OutboxEntry {
                thought: Thought {
                    id: ThoughtId::from_uuid(r.id),
                    user_id: UserId::from_uuid(r.user_id),
                    content: Content::new_remote(r.content),
                    in_reply_to_id: r.in_reply_to_id.map(ThoughtId::from_uuid),
                    in_reply_to_url: None,
                    ap_id: None,
                    visibility: Visibility::Public,
                    content_warning: r.content_warning,
                    sensitive: r.sensitive,
                    local: true,
                    created_at: r.created_at,
                    updated_at: r.updated_at,
                },
                author_username: Username::from_trusted(r.username),
            })
            .collect())
    }

    async fn find_remote_actor_id(&self, actor_ap_url: &Url) -> Result<Option<UserId>, DomainError> {
        sqlx::query_scalar::<_, uuid::Uuid>("SELECT id FROM users WHERE ap_id=$1")
            .bind(actor_ap_url.as_str())
            .fetch_optional(&self.pool)
            .await
            .map_err(|e| DomainError::Internal(e.to_string()))
            .map(|o| o.map(UserId::from_uuid))
    }

    async fn intern_remote_actor(&self, actor_ap_url: &Url) -> Result<UserId, DomainError> {
        if let Some(id) = self.find_remote_actor_id(actor_ap_url).await? {
            return Ok(id);
        }
        let new_id = uuid::Uuid::new_v4();
        let handle = actor_ap_url.path().trim_start_matches('/').replace('/', "_");
        sqlx::query(
            "INSERT INTO users(id,username,email,password_hash,local,ap_id,created_at,updated_at)
             VALUES($1,$2,$3,'',false,$4,NOW(),NOW()) ON CONFLICT(ap_id) DO NOTHING",
        )
        .bind(new_id)
        .bind(&handle)
        .bind(format!("{}@remote", new_id))
        .bind(actor_ap_url.as_str())
        .execute(&self.pool)
        .await
        .map_err(|e| DomainError::Internal(e.to_string()))?;
        // Re-fetch to get whichever id won the race
        self.find_remote_actor_id(actor_ap_url)
            .await?
            .ok_or_else(|| DomainError::Internal("intern_remote_actor: insert succeeded but row not found".into()))
    }

    async fn accept_note(
        &self,
        ap_id: &Url,
        author_id: &UserId,
        content: &str,
        published: DateTime<Utc>,
        sensitive: bool,
        content_warning: Option<String>,
    ) -> Result<(), DomainError> {
        let capped: String = content.chars().take(500).collect();
        sqlx::query(
            "INSERT INTO thoughts(id,user_id,content,ap_id,visibility,sensitive,local,content_warning,created_at)
             VALUES($1,$2,$3,$4,'public',$5,false,$6,$7) ON CONFLICT(ap_id) DO NOTHING",
        )
        .bind(uuid::Uuid::new_v4())
        .bind(author_id.as_uuid())
        .bind(&capped)
        .bind(ap_id.as_str())
        .bind(sensitive)
        .bind(content_warning)
        .bind(published)
        .execute(&self.pool)
        .await
        .map_err(|e| DomainError::Internal(e.to_string()))
        .map(|_| ())
    }

    async fn apply_note_update(&self, ap_id: &Url, new_content: &str) -> Result<(), DomainError> {
        let capped: String = new_content.chars().take(500).collect();
        sqlx::query("UPDATE thoughts SET content=$2,updated_at=NOW() WHERE ap_id=$1 AND local=false")
            .bind(ap_id.as_str())
            .bind(&capped)
            .execute(&self.pool)
            .await
            .map_err(|e| DomainError::Internal(e.to_string()))
            .map(|_| ())
    }

    async fn retract_note(&self, ap_id: &Url) -> Result<(), DomainError> {
        sqlx::query("DELETE FROM thoughts WHERE ap_id=$1 AND local=false")
            .bind(ap_id.as_str())
            .execute(&self.pool)
            .await
            .map_err(|e| DomainError::Internal(e.to_string()))
            .map(|_| ())
    }

    async fn retract_actor_notes(&self, actor_ap_url: &Url) -> Result<(), DomainError> {
        sqlx::query(
            "DELETE FROM thoughts WHERE local=false AND user_id=(SELECT id FROM users WHERE ap_id=$1)",
        )
        .bind(actor_ap_url.as_str())
        .execute(&self.pool)
        .await
        .map_err(|e| DomainError::Internal(e.to_string()))
        .map(|_| ())
    }

    async fn count_local_notes(&self) -> Result<u64, DomainError> {
        let n: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM thoughts WHERE local=true")
            .fetch_one(&self.pool)
            .await
            .map_err(|e| DomainError::Internal(e.to_string()))?;
        Ok(n as u64)
    }
}

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

    #[sqlx::test(migrations = "./migrations")]
    async fn intern_remote_actor_is_idempotent(pool: sqlx::PgPool) {
        let repo = PgActivityPubRepository::new(pool);
        let url = url::Url::parse("https://mastodon.social/users/alice").unwrap();
        let id1 = repo.intern_remote_actor(&url).await.unwrap();
        let id2 = repo.intern_remote_actor(&url).await.unwrap();
        assert_eq!(id1, id2);
    }

    #[sqlx::test(migrations = "./migrations")]
    async fn accept_and_retract_note(pool: sqlx::PgPool) {
        let repo = PgActivityPubRepository::new(pool);
        let actor_url = url::Url::parse("https://remote.example/users/bob").unwrap();
        let ap_id = url::Url::parse("https://remote.example/notes/1").unwrap();
        let author = repo.intern_remote_actor(&actor_url).await.unwrap();
        repo.accept_note(&ap_id, &author, "hello from remote", chrono::Utc::now(), false, None)
            .await
            .unwrap();
        repo.retract_note(&ap_id).await.unwrap();
    }

    #[sqlx::test(migrations = "./migrations")]
    async fn count_local_notes_excludes_remote(pool: sqlx::PgPool) {
        let repo = PgActivityPubRepository::new(pool);
        assert_eq!(repo.count_local_notes().await.unwrap(), 0);
    }
}