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

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

#[derive(sqlx::FromRow)]
pub(crate) struct ThoughtRow {
    pub id: uuid::Uuid,
    pub user_id: uuid::Uuid,
    pub content: String,
    pub in_reply_to_id: Option<uuid::Uuid>,
    pub in_reply_to_url: Option<String>,
    pub ap_id: Option<String>,
    pub visibility: String,
    pub content_warning: Option<String>,
    pub sensitive: bool,
    pub local: bool,
    pub created_at: DateTime<Utc>,
    pub updated_at: Option<DateTime<Utc>>,
}

impl From<ThoughtRow> for Thought {
    fn from(r: ThoughtRow) -> Self {
        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: r.in_reply_to_url,
            ap_id: r.ap_id,
            visibility: Visibility::from_str(&r.visibility),
            content_warning: r.content_warning,
            sensitive: r.sensitive,
            local: r.local,
            created_at: r.created_at,
            updated_at: r.updated_at,
        }
    }
}

const THOUGHT_SELECT: &str =
    "SELECT id,user_id,content,in_reply_to_id,in_reply_to_url,ap_id,visibility,content_warning,sensitive,local,created_at,updated_at FROM thoughts";

#[async_trait]
impl ThoughtRepository for PgThoughtRepository {
    async fn save(&self, t: &Thought) -> Result<(), DomainError> {
        sqlx::query(
            "INSERT INTO thoughts(id,user_id,content,in_reply_to_id,in_reply_to_url,ap_id,visibility,content_warning,sensitive,local,created_at)
             VALUES($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11)
             ON CONFLICT(id) DO UPDATE SET content=EXCLUDED.content,updated_at=NOW()"
        )
        .bind(t.id.as_uuid())
        .bind(t.user_id.as_uuid())
        .bind(t.content.as_str())
        .bind(t.in_reply_to_id.as_ref().map(|x| x.as_uuid()))
        .bind(&t.in_reply_to_url)
        .bind(&t.ap_id)
        .bind(t.visibility.as_str())
        .bind(&t.content_warning)
        .bind(t.sensitive)
        .bind(t.local)
        .bind(t.created_at)
        .execute(&self.pool)
        .await
        .map_err(|e| DomainError::Internal(e.to_string()))
        .map(|_| ())
    }

    async fn find_by_id(&self, id: &ThoughtId) -> Result<Option<Thought>, DomainError> {
        sqlx::query_as::<_, ThoughtRow>(&format!("{THOUGHT_SELECT} WHERE id=$1"))
            .bind(id.as_uuid())
            .fetch_optional(&self.pool)
            .await
            .map_err(|e| DomainError::Internal(e.to_string()))
            .map(|o| o.map(Thought::from))
    }

    async fn delete(&self, id: &ThoughtId, user_id: &UserId) -> Result<(), DomainError> {
        let r = sqlx::query("DELETE FROM thoughts WHERE id=$1 AND user_id=$2")
            .bind(id.as_uuid())
            .bind(user_id.as_uuid())
            .execute(&self.pool)
            .await
            .map_err(|e| DomainError::Internal(e.to_string()))?;
        if r.rows_affected() == 0 { return Err(DomainError::NotFound); }
        Ok(())
    }

    async fn update_content(&self, id: &ThoughtId, content: &Content) -> Result<(), DomainError> {
        sqlx::query("UPDATE thoughts SET content=$2,updated_at=NOW() WHERE id=$1")
            .bind(id.as_uuid())
            .bind(content.as_str())
            .execute(&self.pool)
            .await
            .map_err(|e| DomainError::Internal(e.to_string()))
            .map(|_| ())
    }

    async fn get_thread(&self, id: &ThoughtId) -> Result<Vec<Thought>, DomainError> {
        sqlx::query_as::<_, ThoughtRow>(
            &format!("{THOUGHT_SELECT} WHERE id=$1 OR in_reply_to_id=$1 ORDER BY created_at ASC")
        )
        .bind(id.as_uuid())
        .fetch_all(&self.pool)
        .await
        .map_err(|e| DomainError::Internal(e.to_string()))
        .map(|rows| rows.into_iter().map(Thought::from).collect())
    }

    async fn list_by_user(&self, user_id: &UserId, page: &PageParams) -> Result<Paginated<FeedEntry>, DomainError> {
        let total: i64 = sqlx::query_scalar("SELECT COUNT(*) FROM thoughts WHERE user_id=$1")
            .bind(user_id.as_uuid())
            .fetch_one(&self.pool)
            .await
            .map_err(|e| DomainError::Internal(e.to_string()))?;

        let rows = sqlx::query_as::<_, ThoughtRow>(
            &format!("{THOUGHT_SELECT} WHERE user_id=$1 ORDER BY created_at DESC LIMIT $2 OFFSET $3")
        )
        .bind(user_id.as_uuid())
        .bind(page.limit())
        .bind(page.offset())
        .fetch_all(&self.pool)
        .await
        .map_err(|e| DomainError::Internal(e.to_string()))?;

        let author = sqlx::query_as::<_, crate::user::UserRow>(
            "SELECT id,username,email,password_hash,display_name,bio,avatar_url,header_url,custom_css,local,ap_id,inbox_url,public_key,private_key,created_at,updated_at FROM users WHERE id=$1"
        )
        .bind(user_id.as_uuid())
        .fetch_optional(&self.pool)
        .await
        .map_err(|e| DomainError::Internal(e.to_string()))?
        .ok_or(DomainError::NotFound)?;
        let author = User::from(author);

        let items = rows.into_iter().map(|r| {
            let thought = Thought::from(r);
            FeedEntry {
                thought,
                author: author.clone(),
                like_count: 0,
                boost_count: 0,
                reply_count: 0,
                liked_by_viewer: false,
                boosted_by_viewer: false,
            }
        }).collect();

        Ok(Paginated { items, total, page: page.page, per_page: page.per_page })
    }
}

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

    async fn seed_user(pool: &sqlx::PgPool, username: &str, email: &str) -> User {
        let repo = PgUserRepository::new(pool.clone());
        let u = User::new_local(
            UserId::new(),
            Username::new(username).unwrap(),
            Email::new(email).unwrap(),
            PasswordHash("h".into()),
        );
        repo.save(&u).await.unwrap();
        u
    }

    #[sqlx::test(migrations = "./migrations")]
    async fn save_and_find_thought(pool: sqlx::PgPool) {
        let user = seed_user(&pool, "alice", "alice@ex.com").await;
        let repo = PgThoughtRepository::new(pool);
        let t = Thought::new_local(
            ThoughtId::new(),
            user.id.clone(),
            Content::new_local("hello world").unwrap(),
            None,
            Visibility::Public,
            None,
            false,
        );
        repo.save(&t).await.unwrap();
        let found = repo.find_by_id(&t.id).await.unwrap().unwrap();
        assert_eq!(found.content.as_str(), "hello world");
        assert!(found.local);
    }

    #[sqlx::test(migrations = "./migrations")]
    async fn delete_thought(pool: sqlx::PgPool) {
        let user = seed_user(&pool, "bob", "bob@ex.com").await;
        let repo = PgThoughtRepository::new(pool);
        let t = Thought::new_local(ThoughtId::new(), user.id.clone(), Content::new_local("bye").unwrap(), None, Visibility::Public, None, false);
        repo.save(&t).await.unwrap();
        repo.delete(&t.id, &user.id).await.unwrap();
        assert!(repo.find_by_id(&t.id).await.unwrap().is_none());
    }

    #[sqlx::test(migrations = "./migrations")]
    async fn delete_wrong_owner_returns_not_found(pool: sqlx::PgPool) {
        let alice = seed_user(&pool, "alice", "alice@ex.com").await;
        let bob = seed_user(&pool, "bob", "bob@ex.com").await;
        let repo = PgThoughtRepository::new(pool);
        let t = Thought::new_local(ThoughtId::new(), alice.id.clone(), Content::new_local("secret").unwrap(), None, Visibility::Public, None, false);
        repo.save(&t).await.unwrap();
        let err = repo.delete(&t.id, &bob.id).await.unwrap_err();
        assert!(matches!(err, DomainError::NotFound));
    }

    #[sqlx::test(migrations = "./migrations")]
    async fn get_thread_returns_root_and_replies(pool: sqlx::PgPool) {
        let user = seed_user(&pool, "charlie", "charlie@ex.com").await;
        let repo = PgThoughtRepository::new(pool);
        let root = Thought::new_local(ThoughtId::new(), user.id.clone(), Content::new_local("root").unwrap(), None, Visibility::Public, None, false);
        let reply = Thought::new_local(ThoughtId::new(), user.id.clone(), Content::new_local("reply").unwrap(), Some(root.id.clone()), Visibility::Public, None, false);
        repo.save(&root).await.unwrap();
        repo.save(&reply).await.unwrap();
        let thread = repo.get_thread(&root.id).await.unwrap();
        assert_eq!(thread.len(), 2);
    }
}