//! Database queries for the `admin_providers` table.
//!
//! Provides CRUD operations for the admin-curated LLM provider catalog.

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

use crate::errors::AppError;
use crate::models::provider::{AdminProvider, ProviderModel};

/// Row type returned by sqlx queries against the `admin_providers` table.
#[derive(Debug, sqlx::FromRow)]
struct ProviderRow {
    id: Uuid,
    provider_name: String,
    display_name: String,
    models_scraping: serde_json::Value,
    models_websearch: serde_json::Value,
    is_enabled: bool,
    created_at: chrono::DateTime<chrono::Utc>,
    updated_at: chrono::DateTime<chrono::Utc>,
}

impl TryFrom<ProviderRow> for AdminProvider {
    type Error = AppError;

    fn try_from(row: ProviderRow) -> Result<Self, Self::Error> {
        let models_scraping: Vec<ProviderModel> =
            serde_json::from_value(row.models_scraping).map_err(|e| {
                AppError::Internal(anyhow::anyhow!("Failed to parse provider models_scraping JSON: {}", e))
            })?;
        let models_websearch: Vec<ProviderModel> =
            serde_json::from_value(row.models_websearch).map_err(|e| {
                AppError::Internal(anyhow::anyhow!("Failed to parse provider models_websearch JSON: {}", e))
            })?;

        Ok(Self {
            id: row.id,
            provider_name: row.provider_name,
            display_name: row.display_name,
            models_scraping,
            models_websearch,
            is_enabled: row.is_enabled,
            created_at: row.created_at,
            updated_at: row.updated_at,
        })
    }
}

/// List all providers (admin view, includes disabled).
pub async fn list_all(pool: &PgPool) -> Result<Vec<AdminProvider>, AppError> {
    let rows = sqlx::query_as::<_, ProviderRow>(
        r#"
        SELECT id, provider_name, display_name, models_scraping, models_websearch, is_enabled, created_at, updated_at
        FROM admin_providers
        ORDER BY provider_name
        "#,
    )
    .fetch_all(pool)
    .await?;

    rows.into_iter().map(AdminProvider::try_from).collect()
}

/// Get a provider by its UUID.
pub async fn get_by_id(pool: &PgPool, id: Uuid) -> Result<Option<AdminProvider>, AppError> {
    let row = sqlx::query_as::<_, ProviderRow>(
        r#"
        SELECT id, provider_name, display_name, models_scraping, models_websearch, is_enabled, created_at, updated_at
        FROM admin_providers
        WHERE id = $1
        "#,
    )
    .bind(id)
    .fetch_optional(pool)
    .await?;

    row.map(AdminProvider::try_from).transpose()
}

/// Get a provider by its unique name (e.g., "gemini", "openai").
pub async fn get_by_name(pool: &PgPool, name: &str) -> Result<Option<AdminProvider>, AppError> {
    let row = sqlx::query_as::<_, ProviderRow>(
        r#"
        SELECT id, provider_name, display_name, models_scraping, models_websearch, is_enabled, created_at, updated_at
        FROM admin_providers
        WHERE provider_name = $1
        "#,
    )
    .bind(name)
    .fetch_optional(pool)
    .await?;

    row.map(AdminProvider::try_from).transpose()
}

/// Create a new provider. Returns the created provider.
///
/// The caller is responsible for validating the request before calling this.
pub async fn create(
    pool: &PgPool,
    provider_name: &str,
    display_name: &str,
    models_scraping: &[ProviderModel],
    models_websearch: &[ProviderModel],
    is_enabled: bool,
) -> Result<AdminProvider, AppError> {
    let models_scraping_json = serde_json::to_value(models_scraping).map_err(|e| {
        AppError::Internal(anyhow::anyhow!("Failed to serialize models_scraping: {}", e))
    })?;
    let models_websearch_json = serde_json::to_value(models_websearch).map_err(|e| {
        AppError::Internal(anyhow::anyhow!("Failed to serialize models_websearch: {}", e))
    })?;

    let row = sqlx::query_as::<_, ProviderRow>(
        r#"
        INSERT INTO admin_providers (provider_name, display_name, models_scraping, models_websearch, is_enabled)
        VALUES ($1, $2, $3, $4, $5)
        RETURNING id, provider_name, display_name, models_scraping, models_websearch, is_enabled, created_at, updated_at
        "#,
    )
    .bind(provider_name)
    .bind(display_name)
    .bind(&models_scraping_json)
    .bind(&models_websearch_json)
    .bind(is_enabled)
    .fetch_one(pool)
    .await?;

    AdminProvider::try_from(row)
}

/// Update an existing provider by ID.
///
/// Only updates the fields that are `Some` in the arguments.
/// Returns the updated provider, or `None` if the ID was not found.
pub async fn update(
    pool: &PgPool,
    id: Uuid,
    display_name: Option<&str>,
    models_scraping: Option<&[ProviderModel]>,
    models_websearch: Option<&[ProviderModel]>,
    is_enabled: Option<bool>,
) -> Result<Option<AdminProvider>, AppError> {
    let models_scraping_json = models_scraping
        .map(|m| {
            serde_json::to_value(m)
                .map_err(|e| AppError::Internal(anyhow::anyhow!("Failed to serialize models_scraping: {}", e)))
        })
        .transpose()?;
    let models_websearch_json = models_websearch
        .map(|m| {
            serde_json::to_value(m)
                .map_err(|e| AppError::Internal(anyhow::anyhow!("Failed to serialize models_websearch: {}", e)))
        })
        .transpose()?;

    let row = sqlx::query_as::<_, ProviderRow>(
        r#"
        UPDATE admin_providers SET
            display_name = COALESCE($2, display_name),
            models_scraping = COALESCE($3, models_scraping),
            models_websearch = COALESCE($4, models_websearch),
            is_enabled = COALESCE($5, is_enabled),
            updated_at = now()
        WHERE id = $1
        RETURNING id, provider_name, display_name, models_scraping, models_websearch, is_enabled, created_at, updated_at
        "#,
    )
    .bind(id)
    .bind(display_name)
    .bind(models_scraping_json)
    .bind(models_websearch_json)
    .bind(is_enabled)
    .fetch_optional(pool)
    .await?;

    row.map(AdminProvider::try_from).transpose()
}

/// Delete a provider by ID.
///
/// Returns `true` if a row was deleted, `false` if the ID was not found.
pub async fn delete(pool: &PgPool, id: Uuid) -> Result<bool, AppError> {
    let result = sqlx::query("DELETE FROM admin_providers WHERE id = $1")
        .bind(id)
        .execute(pool)
        .await?;

    Ok(result.rows_affected() > 0)
}

/// List only enabled providers (for the public config endpoint).
///
/// Returns providers where `is_enabled = true`, ordered by provider name.
pub async fn list_enabled(pool: &PgPool) -> Result<Vec<AdminProvider>, AppError> {
    let rows = sqlx::query_as::<_, ProviderRow>(
        r#"
        SELECT id, provider_name, display_name, models_scraping, models_websearch, is_enabled, created_at, updated_at
        FROM admin_providers
        WHERE is_enabled = true
        ORDER BY provider_name
        "#,
    )
    .fetch_all(pool)
    .await?;

    rows.into_iter().map(AdminProvider::try_from).collect()
}