use axum::Router;
use axum::extract::{Path, Query, State};
use axum::http::header;
use axum::response::{IntoResponse, Response};
use axum::routing::get;
use serde::Deserialize;
use uuid::Uuid;

use crate::error::ApiError;
use crate::extractors::AuthenticatedUser;
use crate::state::AppState;

pub fn router() -> Router<AppState> {
    Router::new().route("/attachments/{id}", get(get_attachment))
}

/// Größen-/Format-Parameter für das gerenderte Vorschaubild. Alle optional
/// mit sinnvollen Defaults — die App kann pro Anwendungsfall (Thumbnail vs.
/// Vollbild) abweichende Werte anfragen.
#[derive(Debug, Deserialize)]
pub struct PreviewQuery {
    #[serde(default = "default_dimension")]
    pub w: u32,
    #[serde(default = "default_dimension")]
    pub h: u32,
    #[serde(default = "default_quality")]
    pub q: u32,
    #[serde(default = "default_ext")]
    pub ext: String,
    #[serde(default = "default_page")]
    pub page: String,
}

fn default_dimension() -> u32 {
    1024
}
fn default_quality() -> u32 {
    85
}
fn default_ext() -> String {
    "jpeg".to_string()
}
fn default_page() -> String {
    "1".to_string()
}

/// Liefert ein gerendertes Vorschaubild des Attachments (Bytes), geladen
/// aus DOCUframe. Auflösung/Format über Query-Parameter steuerbar
/// (`?w=&h=&q=&ext=&page=`).
#[utoipa::path(
    get,
    path = "/attachments/{id}",
    tag = "attachments",
    params(
        ("id" = Uuid, Path, description = "Attachment-Id (unsere UUID)"),
        ("w" = Option<u32>, Query, description = "Breite in Pixeln (Default 1024)"),
        ("h" = Option<u32>, Query, description = "Höhe in Pixeln (Default 1024)"),
        ("q" = Option<u32>, Query, description = "Qualität 0–100 (Default 85)"),
        ("ext" = Option<String>, Query, description = "png|jpeg|jpg|webp|tiff (Default jpeg)"),
        ("page" = Option<String>, Query, description = "Seitennummer (Default 1)"),
    ),
    responses(
        (status = 200, description = "Vorschaubild (Bytes)", content_type = "image/jpeg"),
        (status = 401, description = "Authentifizierung fehlgeschlagen"),
        (status = 404, description = "Attachment nicht gefunden")
    ),
    security(("bearer_auth" = []))
)]
pub async fn get_attachment(
    State(state): State<AppState>,
    AuthenticatedUser(claims): AuthenticatedUser,
    Path(id): Path<Uuid>,
    Query(query): Query<PreviewQuery>,
) -> Result<Response, ApiError> {
    tracing::info!(actor = claims.personalnummer, %id, "attachment.preview");
    // DOCUframe-Parameterschema: width_height_quality_extension.
    let parameters = format!("{}_{}_{}_{}", query.w, query.h, query.q, query.ext);
    let preview = state
        .get_attachment_preview
        .execute(id, parameters, query.page)
        .await?;

    Ok((
        [(header::CONTENT_TYPE, preview.content_type)],
        preview.bytes,
    )
        .into_response())
}