use async_trait::async_trait;
use chrono::{DateTime, Utc};
use sqlx::PgPool;
use domain::{
    errors::DomainError,
    models::{feed::{FeedEntry, PageParams, Paginated}, thought::Thought, user::User},
    ports::FeedRepository,
    value_objects::{Content, Email, PasswordHash, ThoughtId, UserId, Username},
};
use domain::models::thought::Visibility;

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

#[derive(sqlx::FromRow)]
struct FeedRow {
    thought_id: uuid::Uuid,
    t_user_id: uuid::Uuid,
    content: String,
    in_reply_to_id: Option<uuid::Uuid>,
    in_reply_to_url: Option<String>,
    t_ap_id: Option<String>,
    visibility: String,
    content_warning: Option<String>,
    sensitive: bool,
    t_local: bool,
    thought_created_at: DateTime<Utc>,
    updated_at: Option<DateTime<Utc>>,
    author_id: uuid::Uuid,
    username: String,
    email: String,
    password_hash: String,
    display_name: Option<String>,
    bio: Option<String>,
    avatar_url: Option<String>,
    header_url: Option<String>,
    custom_css: Option<String>,
    author_local: bool,
    u_ap_id: Option<String>,
    inbox_url: Option<String>,
    public_key: Option<String>,
    private_key: Option<String>,
    author_created_at: DateTime<Utc>,
    author_updated_at: DateTime<Utc>,
    like_count: i64,
    boost_count: i64,
    reply_count: i64,
}

const FEED_SELECT: &str = "
    SELECT
        t.id AS thought_id, t.user_id AS t_user_id, t.content,
        t.in_reply_to_id, t.in_reply_to_url, t.ap_id AS t_ap_id,
        t.visibility, t.content_warning, t.sensitive, t.local AS t_local,
        t.created_at AS thought_created_at, t.updated_at,
        u.id AS author_id, u.username, u.email, u.password_hash,
        u.display_name, u.bio, u.avatar_url, u.header_url, u.custom_css,
        u.local AS author_local, u.ap_id AS u_ap_id, u.inbox_url,
        u.public_key, u.private_key,
        u.created_at AS author_created_at, u.updated_at AS author_updated_at,
        (SELECT COUNT(*) FROM likes l WHERE l.thought_id=t.id) AS like_count,
        (SELECT COUNT(*) FROM boosts b WHERE b.thought_id=t.id) AS boost_count,
        (SELECT COUNT(*) FROM thoughts r WHERE r.in_reply_to_id=t.id) AS reply_count
    FROM thoughts t JOIN users u ON u.id=t.user_id";

fn row_to_entry(r: FeedRow) -> FeedEntry {
    let thought = Thought {
        id: ThoughtId::from_uuid(r.thought_id),
        user_id: UserId::from_uuid(r.t_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: r.in_reply_to_url,
        ap_id: r.t_ap_id,
        visibility: Visibility::from_str(&r.visibility),
        content_warning: r.content_warning,
        sensitive: r.sensitive,
        local: r.t_local,
        created_at: r.thought_created_at,
        updated_at: r.updated_at,
    };
    let author = User {
        id: UserId::from_uuid(r.author_id),
        username: Username::from_trusted(r.username),
        email: Email::from_trusted(r.email),
        password_hash: PasswordHash(r.password_hash),
        display_name: r.display_name, bio: r.bio,
        avatar_url: r.avatar_url, header_url: r.header_url, custom_css: r.custom_css,
        local: r.author_local, ap_id: r.u_ap_id, inbox_url: r.inbox_url,
        public_key: r.public_key, private_key: r.private_key,
        created_at: r.author_created_at, updated_at: r.author_updated_at,
    };
    FeedEntry { thought, author, like_count: r.like_count, boost_count: r.boost_count, reply_count: r.reply_count, liked_by_viewer: false, boosted_by_viewer: false }
}

#[async_trait]
impl FeedRepository for PgFeedRepository {
    async fn home_feed(&self, following_ids: &[UserId], page: &PageParams, _viewer_id: Option<&UserId>) -> Result<Paginated<FeedEntry>, DomainError> {
        let ids: Vec<uuid::Uuid> = following_ids.iter().map(|id| id.as_uuid()).collect();
        let total: i64 = sqlx::query_scalar(
            "SELECT COUNT(*) FROM thoughts t WHERE t.user_id=ANY($1) AND t.visibility='public'"
        ).bind(&ids).fetch_one(&self.pool).await.map_err(|e| DomainError::Internal(e.to_string()))?;

        let sql = format!("{FEED_SELECT} WHERE t.user_id=ANY($1) AND t.visibility='public' ORDER BY t.created_at DESC LIMIT $2 OFFSET $3");
        let rows = sqlx::query_as::<_, FeedRow>(&sql)
            .bind(&ids).bind(page.limit()).bind(page.offset())
            .fetch_all(&self.pool).await.map_err(|e| DomainError::Internal(e.to_string()))?;

        Ok(Paginated { items: rows.into_iter().map(row_to_entry).collect(), total, page: page.page, per_page: page.per_page })
    }

    async fn public_feed(&self, page: &PageParams, _viewer_id: Option<&UserId>) -> Result<Paginated<FeedEntry>, DomainError> {
        let total: i64 = sqlx::query_scalar(
            "SELECT COUNT(*) FROM thoughts t WHERE t.local=true AND t.visibility='public'"
        ).fetch_one(&self.pool).await.map_err(|e| DomainError::Internal(e.to_string()))?;

        let sql = format!("{FEED_SELECT} WHERE t.local=true AND t.visibility='public' ORDER BY t.created_at DESC LIMIT $1 OFFSET $2");
        let rows = sqlx::query_as::<_, FeedRow>(&sql)
            .bind(page.limit()).bind(page.offset())
            .fetch_all(&self.pool).await.map_err(|e| DomainError::Internal(e.to_string()))?;

        Ok(Paginated { items: rows.into_iter().map(row_to_entry).collect(), total, page: page.page, per_page: page.per_page })
    }

    async fn search(&self, query: &str, page: &PageParams, _viewer_id: Option<&UserId>) -> Result<Paginated<FeedEntry>, DomainError> {
        let pattern = format!("%{}%", query.replace('%', "\\%").replace('_', "\\_"));
        let total: i64 = sqlx::query_scalar(
            "SELECT COUNT(*) FROM thoughts t WHERE t.content ILIKE $1 AND t.visibility='public'"
        ).bind(&pattern).fetch_one(&self.pool).await.map_err(|e| DomainError::Internal(e.to_string()))?;

        let sql = format!("{FEED_SELECT} WHERE t.content ILIKE $1 AND t.visibility='public' ORDER BY t.created_at DESC LIMIT $2 OFFSET $3");
        let rows = sqlx::query_as::<_, FeedRow>(&sql)
            .bind(&pattern).bind(page.limit()).bind(page.offset())
            .fetch_all(&self.pool).await.map_err(|e| DomainError::Internal(e.to_string()))?;

        Ok(Paginated { items: rows.into_iter().map(row_to_entry).collect(), total, page: page.page, per_page: page.per_page })
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use domain::{models::{thought::{Thought, Visibility}, user::User}, ports::{ThoughtRepository, UserRepository}, value_objects::*};
    use crate::{thought::PgThoughtRepository, user::PgUserRepository};

    async fn seed(pool: &sqlx::PgPool, username: &str, content: &str) -> (User, Thought) {
        let urepo = PgUserRepository::new(pool.clone());
        let trepo = PgThoughtRepository::new(pool.clone());
        let u = User::new_local(UserId::new(), Username::new(username).unwrap(), Email::new(format!("{username}@ex.com")).unwrap(), PasswordHash("h".into()));
        urepo.save(&u).await.unwrap();
        let t = Thought::new_local(ThoughtId::new(), u.id.clone(), Content::new_local(content).unwrap(), None, Visibility::Public, None, false);
        trepo.save(&t).await.unwrap();
        (u, t)
    }

    #[sqlx::test(migrations = "./migrations")]
    async fn public_feed_returns_local_thoughts(pool: sqlx::PgPool) {
        let (_, _) = seed(&pool, "alice", "hello").await;
        let repo = PgFeedRepository::new(pool);
        let result = repo.public_feed(&PageParams { page: 1, per_page: 20 }, None).await.unwrap();
        assert_eq!(result.total, 1);
        assert_eq!(result.items[0].thought.content.as_str(), "hello");
    }

    #[sqlx::test(migrations = "./migrations")]
    async fn search_returns_matching_thoughts(pool: sqlx::PgPool) {
        let (_, _) = seed(&pool, "alice", "hello world").await;
        let (_, _) = seed(&pool, "bob", "goodbye world").await;
        let repo = PgFeedRepository::new(pool);
        let result = repo.search("hello", &PageParams { page: 1, per_page: 20 }, None).await.unwrap();
        assert_eq!(result.total, 1);
        assert_eq!(result.items[0].thought.content.as_str(), "hello world");
    }
}