//! Module for serializing into `multipart/form-data`
//! ([`reqwest::multipart::Form`])
//!
//! [`reqwest::multipart::Form`]: reqwest::multipart::Form
//!
//! ## How it works
//!
//! You better not know...
//!
//! This whole module is an awful hack and we'll probably stop using it in next
//! versions (in favor of something less automatic, but more simple).

mod error;
mod serializers;

use std::future::Future;

use reqwest::multipart::Form;
use serde::Serialize;

use crate::requests::MultipartPayload;
use error::Error;
use serializers::MultipartSerializer;

/// Serializes given value into [`Form`] **taking all input files out**.
///
/// [`Form`]:  reqwest::multipart::Form
pub(crate) fn to_form<T>(val: &mut T) -> Result<impl Future<Output = Form>, Error>
where
    T: Serialize + MultipartPayload,
{
    let mut form = val.serialize(MultipartSerializer::new())?;

    let mut vec = Vec::with_capacity(1);
    val.move_files(&mut |f| vec.push(f));
    let iter = vec.into_iter();

    let fut = async move {
        for file in iter {
            if file.needs_attach() {
                let id = file.id().to_owned();
                if let Some(part) = file.into_part() {
                    form = form.part(id, part.await);
                }
            }
        }

        form
    };

    Ok(fut)
}

/// Serializes given value into [`Form`].
///
/// [`Form`]:  reqwest::multipart::Form
pub(crate) fn to_form_ref<T: ?Sized>(val: &T) -> Result<impl Future<Output = Form>, Error>
where
    T: Serialize + MultipartPayload,
{
    let mut form = val.serialize(MultipartSerializer::new())?;
    let mut vec = Vec::with_capacity(1);
    val.copy_files(&mut |f| vec.push(f));

    let iter = vec.into_iter();

    let fut = async move {
        for file in iter {
            if file.needs_attach() {
                let id = file.id().to_owned();
                if let Some(part) = file.into_part() {
                    form = form.part(id, part.await);
                }
            }
        }

        form
    };

    Ok(fut)
}

#[cfg(test)]
mod tests {
    use tokio::fs::File;

    use super::to_form_ref;
    use crate::{
        payloads::{self, setters::*},
        types::{
            InputFile, InputMedia, InputMediaAnimation, InputMediaAudio, InputMediaDocument,
            InputMediaPhoto, InputMediaVideo, InputSticker, MessageEntity, MessageEntityKind,
            ParseMode,
        },
    };

    // https://github.com/teloxide/teloxide/issues/473
    #[tokio::test]
    async fn issue_473() {
        to_form_ref(
            &payloads::SendPhoto::new(0, InputFile::file_id("0")).caption_entities([
                MessageEntity {
                    kind: MessageEntityKind::Url,
                    offset: 0,
                    length: 0,
                },
            ]),
        )
        .unwrap()
        .await;
    }

    #[tokio::test]
    async fn test_send_media_group() {
        const CAPTION: &str = "caption";

        to_form_ref(&payloads::SendMediaGroup::new(
            0,
            [
                InputMedia::Photo(
                    InputMediaPhoto::new(InputFile::file("./media/logo.png"))
                        .caption(CAPTION)
                        .parse_mode(ParseMode::MarkdownV2)
                        .caption_entities(entities()),
                ),
                InputMedia::Video(
                    InputMediaVideo::new(InputFile::file_id("17")).supports_streaming(true),
                ),
                InputMedia::Animation(
                    InputMediaAnimation::new(InputFile::read(
                        File::open("./media/example.gif").await.unwrap(),
                    ))
                    .thumb(InputFile::read(
                        File::open("./media/logo.png").await.unwrap(),
                    ))
                    .duration(17),
                ),
                InputMedia::Audio(
                    InputMediaAudio::new(InputFile::url("https://example.com".parse().unwrap()))
                        .performer("a"),
                ),
                InputMedia::Document(InputMediaDocument::new(InputFile::memory(
                    &b"Hello world!"[..],
                ))),
            ],
        ))
        .unwrap()
        .await;
    }

    #[tokio::test]
    async fn test_add_sticker_to_set() {
        to_form_ref(&payloads::AddStickerToSet::new(
            0,
            "name",
            InputSticker::Png(InputFile::file("./media/logo.png")),
            "✈️⚙️",
        ))
        .unwrap()
        .await;
    }

    #[tokio::test]
    async fn test_send_animation() {
        to_form_ref(
            &payloads::SendAnimation::new(0, InputFile::file("./media/logo.png"))
                .caption_entities(entities())
                .thumb(InputFile::read(
                    File::open("./media/logo.png").await.unwrap(),
                ))
                .allow_sending_without_reply(true),
        )
        .unwrap()
        .await;
    }

    fn entities() -> impl Iterator<Item = MessageEntity> {
        <_>::into_iter([
            MessageEntity::new(MessageEntityKind::Url, 0, 0),
            MessageEntity::new(MessageEntityKind::Pre { language: None }, 0, 0),
            MessageEntity::new(
                MessageEntityKind::Pre {
                    language: Some(String::new()),
                },
                0,
                0,
            ),
            MessageEntity::new(MessageEntityKind::Url, 0, 0),
            MessageEntity::new(
                MessageEntityKind::TextLink {
                    url: "https://example.com".parse().unwrap(),
                },
                0,
                0,
            ),
        ])
    }
}