//! Plain multipart upload → Garage (S3-compatible), for `type: file`
//! requirement fields. A raw Axum handler, not a Leptos server fn -
//! those aren't built for binary bodies. The stored object key becomes
//! that field's value in `responses_json` (`app.rs`'s file-input
//! widget), so nothing about `submit_answer`'s generic
//! `Map<String, String>` flow needs to know a file was involved.
#![cfg(feature = "ssr")]

use aws_sdk_s3::config::{BehaviorVersion, Credentials, Region};
use aws_sdk_s3::primitives::ByteStream;
use axum::extract::{Multipart, State};
use axum::http::StatusCode;
use axum::Json;
use serde::Serialize;

use crate::server::AppState;

const MAX_UPLOAD_BYTES: usize = 20 * 1024 * 1024;

#[derive(Clone)]
pub struct Garage {
    client: aws_sdk_s3::Client,
    bucket: String,
}

impl Garage {
    /// Builds a client from `GARAGE_S3_ENDPOINT`/`GARAGE_ACCESS_KEY`/
    /// `GARAGE_SECRET_KEY`/`GARAGE_UPLOADS_BUCKET` - same secret names
    /// dodrenett's own Woodpecker pipeline already uses. `None` (not an
    /// error) when unset, since uploads are optional: everything else
    /// works without Garage configured.
    pub fn from_env() -> Option<Self> {
        let endpoint = std::env::var("GARAGE_S3_ENDPOINT")
            .unwrap_or_else(|_| "http://garage:3900".to_string());
        let access_key = std::env::var("GARAGE_ACCESS_KEY").ok()?;
        let secret_key = std::env::var("GARAGE_SECRET_KEY").ok()?;
        let bucket = std::env::var("GARAGE_UPLOADS_BUCKET")
            .unwrap_or_else(|_| "portal-attachments".to_string());

        let credentials = Credentials::new(access_key, secret_key, None, None, "portal");
        let config = aws_sdk_s3::Config::builder()
            .behavior_version(BehaviorVersion::latest())
            .region(Region::new("garage"))
            .endpoint_url(endpoint)
            .credentials_provider(credentials)
            // Garage expects path-style bucket addressing, not the
            // virtual-hosted `bucket.host` style AWS defaults to.
            .force_path_style(true)
            .build();
        Some(Self {
            client: aws_sdk_s3::Client::from_conf(config),
            bucket,
        })
    }
}

#[derive(Serialize)]
pub struct UploadResponse {
    key: String,
}

/// POST /upload - streams the first `file` field straight through to
/// Garage and hands back its object key. Server-side hygiene beyond the
/// HTML `accept` hint (a UX-only signal, not a boundary): a hard size
/// cap, and the upload is rejected outright if Garage isn't configured
/// rather than silently succeeding nowhere.
pub async fn upload(
    State(state): State<AppState>,
    mut multipart: Multipart,
) -> Result<Json<UploadResponse>, (StatusCode, String)> {
    let garage = state.garage.as_ref().ok_or((
        StatusCode::SERVICE_UNAVAILABLE,
        "uploads are not configured".to_string(),
    ))?;

    while let Some(field) = multipart
        .next_field()
        .await
        .map_err(|e| (StatusCode::BAD_REQUEST, e.to_string()))?
    {
        if field.name() != Some("file") {
            continue;
        }
        let content_type = field
            .content_type()
            .unwrap_or("application/octet-stream")
            .to_string();
        let filename = field.file_name().unwrap_or("upload").to_string();
        let bytes = field
            .bytes()
            .await
            .map_err(|e| (StatusCode::BAD_REQUEST, e.to_string()))?;
        if bytes.len() > MAX_UPLOAD_BYTES {
            return Err((StatusCode::PAYLOAD_TOO_LARGE, "file too large".to_string()));
        }

        let key = format!("{}-{filename}", uuid::Uuid::new_v4());
        garage
            .client
            .put_object()
            .bucket(&garage.bucket)
            .key(&key)
            .body(ByteStream::from(bytes))
            .content_type(content_type)
            .send()
            .await
            .map_err(|e| (StatusCode::BAD_GATEWAY, format!("upload failed: {e}")))?;

        return Ok(Json(UploadResponse { key }));
    }

    Err((StatusCode::BAD_REQUEST, "no file field in request".to_string()))
}