//! Getting a file *onto* a Bambu printer - the other half of
//! `upload_project_file`, which `bambu.rs` stubbed with a `println!` until
//! now. MQTT can start a print, but it can only name a file the printer
//! already has; moving the bytes there is a completely separate protocol.
//!
//! This is deliberately suppaftp's **blocking** client, not its async one,
//! driven from `tokio::task::spawn_blocking` at the single call site in
//! `bambu.rs`. Two reasons:
//!
//! 1. The blocking client takes a plain `native_tls::TlsConnector`, so this
//!    module reuses `BambuTls::build_connector()` exactly as-is and every
//!    TLS trust decision for a printer stays in that one method (which has
//!    a long doc comment explaining some hard-won specifics - duplicating
//!    that reasoning against a second TLS stack is how it drifts).
//! 2. suppaftp's async client needs that second TLS stack
//!    (`async-native-tls`), whose futures-vs-tokio `AsyncRead` mismatch has
//!    already cost this project one debugging session.
//!
//! **Unverified against real hardware.** The port, the username, and
//! implicit TLS are well-established for Bambu LAN mode, and the TLS layer
//! itself is the same one `test_tls_handshake` already proves against a
//! real printer on 8883. But no physical printer has accepted an upload
//! from *this* code yet. Expect the first live run to be where the
//! remaining details get settled - see `bambu.rs::upload_project_file` for
//! the list of specific things to watch.

use std::io::Cursor;

use suppaftp::types::FileType;
use suppaftp::{NativeTlsConnector, NativeTlsFtpStream};

/// Bambu LAN mode speaks *implicit* FTPS: TLS starts the instant the socket
/// opens, with no plaintext `AUTH TLS` negotiation first. That's the older
/// of the two FTPS styles and formally deprecated, which is exactly why
/// suppaftp hides `connect_secure_implicit` behind a `deprecated` cargo
/// feature. The printers only speak this, so the feature is switched on in
/// `Cargo.toml`.
const FTPS_PORT: u16 = 990;

/// The same for every Bambu printer in LAN mode. The password is the same
/// access code MQTT authenticates with - one shared secret, two protocols.
const FTPS_USER: &str = "bblp";

/// Storage the printer's own firmware owns, and the directory Bambu Studio
/// uploads to as well. A `project_file`/`gcode_file` MQTT command can only
/// print something that already lives here.
pub const CACHE_DIR: &str = "cache";

/// The SD card's root, which is where an FTPS login lands and - confirmed
/// live on a P1P, 2026-10-11 - the only directory a `print.project_file`
/// command has been seen to print from.
///
/// The card's two interesting directories hold different things, and a
/// listing of the real P1P is the clearest way to say which:
///
/// - the root holds 43 `<name>.gcode.3mf` files, the printable project
///   archives Bambu Studio sends when it uploads a plate;
/// - `cache/` holds 20 `<project>_plate_N.gcode` files with
///   `<N>_<project>.gcode.bbl` sidecars - the printer's own extracted
///   per-plate working copies.
///
/// Those extracted copies look like the obvious thing to print and are not:
/// `print.gcode_file` with `param: "/cache/Cube_plate_1.gcode"` was
/// rejected (`result: "fail"`) for a file that demonstrably exists, while
/// `print.project_file` with `url: "ftp:///Cube.gcode.3mf"` against the
/// root started a print. So uploads go here, not into `cache/`.
pub const SD_ROOT: &str = "/";

/// Blocking: opens an implicit-FTPS session to `host`, logs in with
/// `access_code`, and writes `data` to `cache/{file_name}`. Returns however
/// many bytes the server reported accepting.
///
/// Takes an already-built `connector` rather than a `&BambuTls` so the
/// caller resolves trust on the async side and this function can be moved
/// wholesale onto a blocking thread - `native_tls::TlsConnector` is `Send`,
/// which is what makes that legal.
pub fn upload(
    host: &str,
    access_code: &str,
    connector: native_tls::TlsConnector,
    dir: &str,
    file_name: &str,
    data: &[u8],
) -> anyhow::Result<u64> {
    let mut ftp = NativeTlsFtpStream::connect_secure_implicit(
        (host, FTPS_PORT),
        NativeTlsConnector::from(connector),
        host,
    )?;

    ftp.login(FTPS_USER, access_code)?;

    // A .3mf is a zip archive and a .gcode has meaningful line endings -
    // either way, letting the server treat the stream as text is free
    // corruption.
    ftp.transfer_type(FileType::Binary)?;
    // `SD_ROOT` means "don't change directory at all" - the FTPS login
    // already lands in the card's root, and `cwd("/")` is a needless round
    // trip that some servers answer less predictably than no request.
    if dir != SD_ROOT {
        ftp.cwd(dir)?;
    }

    // `put_file` wants something that implements `Read`. `data` is already
    // bytes in memory (see `GenericPrinter::upload_project_file`'s doc
    // comment for why it's bytes and not a path), and `Cursor` is the
    // standard way to let something read from a slice - roughly wrapping a
    // Buffer in a stream in Node.
    let mut reader = Cursor::new(data);
    let written = ftp.put_file(file_name, &mut reader)?;

    // Best-effort: the bytes are already delivered and acknowledged, so
    // failing to say goodbye politely isn't worth failing the upload over.
    let _ = ftp.quit();

    Ok(written)
}

/// Blocking: reads one file off the printer's SD card.
///
/// Read-only. The reason this exists: a `.3mf` already on the card is the
/// only record of which filament each of its plates was sliced for, and
/// `ams_mapping` cannot be built without that - see
/// `schemas/bambulab/v1/common/ams/ams_mapping.schema.json`. Printing a
/// project with the wrong mapping is not a cosmetic error; it draws the
/// wrong filament, or none.
pub fn download(
    host: &str,
    access_code: &str,
    connector: native_tls::TlsConnector,
    path: &str,
) -> anyhow::Result<Vec<u8>> {
    let mut ftp = NativeTlsFtpStream::connect_secure_implicit(
        (host, FTPS_PORT),
        NativeTlsConnector::from(connector),
        host,
    )?;

    ftp.login(FTPS_USER, access_code)?;
    // A `.3mf` is a zip archive; letting the server treat it as text is free
    // corruption, exactly as on the way up.
    ftp.transfer_type(FileType::Binary)?;

    // `retr_as_buffer` rather than `retr_as_stream`: suppaftp 12's
    // `TransferStream` finalizes itself on drop, and a project archive is
    // read whole anyway - `plate_filaments` needs the central directory at
    // its end before it can read anything.
    //
    // Confirmed fine at 4.96 MB on the P1P (2026-10-15, byte-identical
    // round trip). The qualifier here used to be "a few hundred KB", which
    // the card itself disproves - the largest project on it is 62 MB, and
    // that one would be held in memory twice during a round trip. Streaming
    // is the answer if that ever matters; it has not yet.
    let bytes = ftp.retr_as_buffer(path)?.into_inner();

    let _ = ftp.quit();

    Ok(bytes)
}

/// Blocking: removes one file from the card.
///
/// The counterpart to `upload`, and the only reason it did not exist before
/// is that nothing had uploaded anything worth removing. It is needed now:
/// the P1P's card already holds 45 project archives and 47 extracted
/// `cache/` entries, so a gateway that uploads a project per job and never
/// removes one is a gateway that eventually fills a customer's SD card and
/// starts failing prints for a reason nobody will connect to this code.
///
/// Deliberately takes one explicit path and does no globbing or recursion:
/// the obvious convenience here ("clear the old ones") is also the obvious
/// way to delete a file somebody printed from last week.
pub fn delete(
    host: &str,
    access_code: &str,
    connector: native_tls::TlsConnector,
    path: &str,
) -> anyhow::Result<()> {
    let mut ftp = NativeTlsFtpStream::connect_secure_implicit(
        (host, FTPS_PORT),
        NativeTlsConnector::from(connector),
        host,
    )?;

    ftp.login(FTPS_USER, access_code)?;
    ftp.rm(path)?;

    let _ = ftp.quit();

    Ok(())
}

/// Blocking: lists `cache/` on the printer.
///
/// Read-only, and the counterpart to `upload`. The previous version of this
/// comment said a `project_file` command "can only print something that is
/// already in this directory", which is wrong twice over: the printable
/// projects are in the root (see `SD_ROOT`), and this directory's contents
/// were rejected when asked for directly. It is still how you find a real
/// slicer-produced `.3mf`
/// to test against, instead of hand-building one and then not knowing
/// whether a failure was the command or the file.
///
/// Returns the server's raw LIST lines rather than parsed entries: Bambu's
/// FTPS server formats them in the usual unix style, but the parsing is the
/// caller's problem until something needs more than the file names.
pub fn list(
    host: &str,
    access_code: &str,
    connector: native_tls::TlsConnector,
    dir: &str,
) -> anyhow::Result<Vec<String>> {
    let mut ftp = NativeTlsFtpStream::connect_secure_implicit(
        (host, FTPS_PORT),
        NativeTlsConnector::from(connector),
        host,
    )?;

    ftp.login(FTPS_USER, access_code)?;
    ftp.transfer_type(FileType::Binary)?;

    let entries = ftp.list(Some(dir))?;

    let _ = ftp.quit();

    Ok(entries)
}