//! Realm management database queries.
//!
//! These queries are used by the owner interface and require the chattyness_owner role.

use sqlx::PgPool;
use uuid::Uuid;

use crate::models::{
    OwnerCreateRealmRequest, RealmDetail, RealmListItem, RealmPrivacy, UpdateRealmRequest,
};
use chattyness_error::AppError;

use super::helpers::{generate_random_token, hash_password};

/// List all realms with owner info (for admin interface).
pub async fn list_realms_with_owner(
    pool: &PgPool,
    limit: i64,
    offset: i64,
) -> Result<Vec<RealmListItem>, AppError> {
    let realms = sqlx::query_as::<_, RealmListItem>(
        r#"
        SELECT
            r.id,
            r.name,
            r.slug,
            r.tagline,
            r.privacy,
            r.is_nsfw,
            r.owner_id,
            u.username as owner_username,
            r.member_count,
            COALESCE((
                SELECT COUNT(*)::INTEGER
                FROM scene.instance_members im
                JOIN realm.scenes s ON im.instance_id = s.id
                WHERE s.realm_id = r.id
            ), 0) AS current_user_count,
            r.created_at
        FROM realm.realms r
        JOIN auth.users u ON r.owner_id = u.id
        ORDER BY r.created_at DESC
        LIMIT $1 OFFSET $2
        "#,
    )
    .bind(limit)
    .bind(offset)
    .fetch_all(pool)
    .await?;

    Ok(realms)
}

/// Search realms by name or slug.
pub async fn search_realms(
    pool: &PgPool,
    query: &str,
    limit: i64,
) -> Result<Vec<RealmListItem>, AppError> {
    let pattern = format!("%{}%", query);
    let realms = sqlx::query_as::<_, RealmListItem>(
        r#"
        SELECT
            r.id,
            r.name,
            r.slug,
            r.tagline,
            r.privacy,
            r.is_nsfw,
            r.owner_id,
            u.username as owner_username,
            r.member_count,
            COALESCE((
                SELECT COUNT(*)::INTEGER
                FROM scene.instance_members im
                JOIN realm.scenes s ON im.instance_id = s.id
                WHERE s.realm_id = r.id
            ), 0) AS current_user_count,
            r.created_at
        FROM realm.realms r
        JOIN auth.users u ON r.owner_id = u.id
        WHERE
            r.name ILIKE $1
            OR r.slug ILIKE $1
        ORDER BY
            CASE
                WHEN r.slug ILIKE $1 THEN 1
                WHEN r.name ILIKE $1 THEN 2
                ELSE 3
            END,
            r.name
        LIMIT $2
        "#,
    )
    .bind(&pattern)
    .bind(limit)
    .fetch_all(pool)
    .await?;

    Ok(realms)
}

/// Create a new realm with an existing user as owner.
#[allow(clippy::too_many_arguments)]
pub async fn create_realm(
    pool: &PgPool,
    owner_id: Uuid,
    name: &str,
    slug: &str,
    description: Option<&str>,
    tagline: Option<&str>,
    privacy: RealmPrivacy,
    is_nsfw: bool,
    max_users: i32,
    allow_guest_access: bool,
    theme_color: Option<&str>,
) -> Result<Uuid, AppError> {
    // Start a transaction
    let mut tx = pool.begin().await?;

    // Create the realm
    let realm_id = sqlx::query_scalar::<_, Uuid>(
        r#"
        INSERT INTO realm.realms (
            name, slug, description, tagline, owner_id,
            privacy, is_nsfw, max_users, allow_guest_access, theme_color
        )
        VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10)
        RETURNING id
        "#,
    )
    .bind(name)
    .bind(slug)
    .bind(description)
    .bind(tagline)
    .bind(owner_id)
    .bind(privacy)
    .bind(is_nsfw)
    .bind(max_users)
    .bind(allow_guest_access)
    .bind(theme_color)
    .fetch_one(&mut *tx)
    .await?;

    // Add owner as realm member with owner role
    sqlx::query(
        r#"
        INSERT INTO realm.memberships (realm_id, user_id, role)
        VALUES ($1, $2, 'owner')
        "#,
    )
    .bind(realm_id)
    .bind(owner_id)
    .execute(&mut *tx)
    .await?;

    tx.commit().await?;

    Ok(realm_id)
}

/// Create a realm with a new user as owner (atomically).
/// Returns (realm_id, user_id, plaintext_token) - the token should be shown to the server owner.
pub async fn create_realm_with_new_owner(
    pool: &PgPool,
    req: &OwnerCreateRealmRequest,
) -> Result<(Uuid, Uuid, String), AppError> {
    let new_owner = req
        .new_owner
        .as_ref()
        .ok_or_else(|| AppError::Validation("new_owner is required".to_string()))?;

    // Generate a random token as the temporary password
    let token = generate_random_token();
    let password_hash = hash_password(&token)?;

    // Start a transaction
    let mut tx = pool.begin().await?;

    // Create the user with force_pw_reset = true
    let user_id = sqlx::query_scalar::<_, Uuid>(
        r#"
        INSERT INTO auth.users (username, email, display_name, password_hash, force_pw_reset)
        VALUES ($1, $2, $3, $4, true)
        RETURNING id
        "#,
    )
    .bind(&new_owner.username)
    .bind(&new_owner.email)
    .bind(&new_owner.display_name)
    .bind(&password_hash)
    .fetch_one(&mut *tx)
    .await?;

    // Create the realm
    let realm_id = sqlx::query_scalar::<_, Uuid>(
        r#"
        INSERT INTO realm.realms (
            name, slug, description, tagline, owner_id,
            privacy, is_nsfw, max_users, allow_guest_access, theme_color
        )
        VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9, $10)
        RETURNING id
        "#,
    )
    .bind(&req.name)
    .bind(&req.slug)
    .bind(&req.description)
    .bind(&req.tagline)
    .bind(user_id)
    .bind(req.privacy)
    .bind(req.is_nsfw)
    .bind(req.max_users)
    .bind(req.allow_guest_access)
    .bind(&req.theme_color)
    .fetch_one(&mut *tx)
    .await?;

    // Add owner as realm member with owner role
    sqlx::query(
        r#"
        INSERT INTO realm.memberships (realm_id, user_id, role)
        VALUES ($1, $2, 'owner')
        "#,
    )
    .bind(realm_id)
    .bind(user_id)
    .execute(&mut *tx)
    .await?;

    tx.commit().await?;

    Ok((realm_id, user_id, token))
}

/// Get a realm by slug with full details for editing.
pub async fn get_realm_by_slug(pool: &PgPool, slug: &str) -> Result<RealmDetail, AppError> {
    let realm = sqlx::query_as::<_, RealmDetail>(
        r#"
        SELECT
            r.id,
            r.name,
            r.slug,
            r.description,
            r.tagline,
            r.owner_id,
            u.username as owner_username,
            u.display_name as owner_display_name,
            r.privacy,
            r.is_nsfw,
            r.min_reputation_tier,
            r.theme_color,
            r.banner_image_path,
            r.thumbnail_path,
            r.max_users,
            r.allow_guest_access,
            r.member_count,
            COALESCE((
                SELECT COUNT(*)::INTEGER
                FROM scene.instance_members im
                JOIN realm.scenes s ON im.instance_id = s.id
                WHERE s.realm_id = r.id
            ), 0) AS current_user_count,
            r.created_at,
            r.updated_at
        FROM realm.realms r
        JOIN auth.users u ON r.owner_id = u.id
        WHERE r.slug = $1
        "#,
    )
    .bind(slug)
    .fetch_optional(pool)
    .await?
    .ok_or_else(|| AppError::NotFound(format!("Realm with slug '{}' not found", slug)))?;

    Ok(realm)
}

/// Update a realm's settings.
pub async fn update_realm(
    pool: &PgPool,
    realm_id: Uuid,
    req: &UpdateRealmRequest,
) -> Result<RealmDetail, AppError> {
    // Update the realm
    sqlx::query(
        r#"
        UPDATE realm.realms
        SET
            name = $1,
            description = $2,
            tagline = $3,
            privacy = $4,
            is_nsfw = $5,
            max_users = $6,
            allow_guest_access = $7,
            theme_color = $8,
            updated_at = now()
        WHERE id = $9
        "#,
    )
    .bind(&req.name)
    .bind(&req.description)
    .bind(&req.tagline)
    .bind(req.privacy)
    .bind(req.is_nsfw)
    .bind(req.max_users)
    .bind(req.allow_guest_access)
    .bind(&req.theme_color)
    .bind(realm_id)
    .execute(pool)
    .await?;

    // Fetch and return the updated realm
    let realm = sqlx::query_as::<_, RealmDetail>(
        r#"
        SELECT
            r.id,
            r.name,
            r.slug,
            r.description,
            r.tagline,
            r.owner_id,
            u.username as owner_username,
            u.display_name as owner_display_name,
            r.privacy,
            r.is_nsfw,
            r.min_reputation_tier,
            r.theme_color,
            r.banner_image_path,
            r.thumbnail_path,
            r.max_users,
            r.allow_guest_access,
            r.member_count,
            COALESCE((
                SELECT COUNT(*)::INTEGER
                FROM scene.instance_members im
                JOIN realm.scenes s ON im.instance_id = s.id
                WHERE s.realm_id = r.id
            ), 0) AS current_user_count,
            r.created_at,
            r.updated_at
        FROM realm.realms r
        JOIN auth.users u ON r.owner_id = u.id
        WHERE r.id = $1
        "#,
    )
    .bind(realm_id)
    .fetch_one(pool)
    .await?;

    Ok(realm)
}

/// Transfer realm ownership to a different user.
pub async fn transfer_realm_ownership(
    pool: &PgPool,
    realm_id: Uuid,
    new_owner_id: Uuid,
) -> Result<(), AppError> {
    let mut tx = pool.begin().await?;

    // Get current owner_id
    let current_owner_id =
        sqlx::query_scalar::<_, Uuid>(r#"SELECT owner_id FROM realm.realms WHERE id = $1"#)
            .bind(realm_id)
            .fetch_one(&mut *tx)
            .await?;

    // Update realm owner
    sqlx::query(r#"UPDATE realm.realms SET owner_id = $1, updated_at = now() WHERE id = $2"#)
        .bind(new_owner_id)
        .bind(realm_id)
        .execute(&mut *tx)
        .await?;

    // Update old owner's membership role to member (or remove?)
    sqlx::query(
        r#"
        UPDATE realm.memberships
        SET role = 'moderator'
        WHERE realm_id = $1 AND user_id = $2
        "#,
    )
    .bind(realm_id)
    .bind(current_owner_id)
    .execute(&mut *tx)
    .await?;

    // Ensure new owner has membership with owner role
    sqlx::query(
        r#"
        INSERT INTO realm.memberships (realm_id, user_id, role)
        VALUES ($1, $2, 'owner')
        ON CONFLICT (realm_id, user_id) DO UPDATE SET role = 'owner'
        "#,
    )
    .bind(realm_id)
    .bind(new_owner_id)
    .execute(&mut *tx)
    .await?;

    tx.commit().await?;
    Ok(())
}