use crate::config::TwitterConfig;
use crate::error::OolatoocsError;
use chrono::Utc;
use futures::{stream, StreamExt};
use log::{debug, error, warn};
use megalodon::entities::{
    attachment::{Attachment, AttachmentType},
    Poll,
};
use oauth1_request::Token;
use reqwest::{
    multipart::{Form, Part},
    Body, Client,
};
use serde::{Deserialize, Serialize};
use std::{error::Error, ops::Not};
use tokio::time::{sleep, Duration};

const TWITTER_API_TWEET_URL: &str = "https://api.twitter.com/2/tweets";
const TWITTER_UPLOAD_MEDIA_URL: &str = "https://upload.twitter.com/1.1/media/upload.json";
const TWITTER_METADATA_MEDIA_URL: &str =
    "https://upload.twitter.com/1.1/media/metadata/create.json";

// I don’t know, don’t ask me
#[derive(oauth1_request::Request)]
struct EmptyRequest {}

#[derive(Serialize, Debug)]
struct Tweet {
    text: String,
    #[serde(skip_serializing_if = "Option::is_none")]
    media: Option<TweetMediasIds>,
    #[serde(skip_serializing_if = "Option::is_none")]
    reply: Option<TweetReply>,
    #[serde(skip_serializing_if = "Option::is_none")]
    poll: Option<TweetPoll>,
}

#[derive(Serialize, Debug)]
struct TweetMediasIds {
    media_ids: Vec<String>,
}

#[derive(Serialize, Debug)]
struct TweetReply {
    in_reply_to_tweet_id: String,
}

#[derive(Serialize, Debug)]
pub struct TweetPoll {
    pub options: Vec<String>,
    pub duration_minutes: u16,
}

#[derive(Deserialize, Debug)]
struct TweetResponse {
    data: TweetResponseData,
}

#[derive(Deserialize, Debug)]
struct TweetResponseData {
    id: String,
}

#[derive(Deserialize, Debug)]
struct UploadMediaResponse {
    media_id: u64,
    processing_info: Option<UploadMediaResponseProcessingInfo>,
}

#[derive(Deserialize, Debug)]
struct UploadMediaResponseProcessingInfo {
    state: UploadMediaResponseProcessingInfoState,
    check_after_secs: Option<u64>,
}

#[derive(Deserialize, Debug)]
enum UploadMediaResponseProcessingInfoState {
    #[serde(rename = "failed")]
    Failed,
    #[serde(rename = "succeeded")]
    Succeeded,
    #[serde(rename = "pending")]
    Pending,
    #[serde(rename = "in_progress")]
    InProgress,
}

#[derive(Serialize, Debug)]
struct MediaMetadata {
    media_id: u64,
    alt_text: MediaMetadataAltText,
}

#[derive(Serialize, Debug)]
struct MediaMetadataAltText {
    text: String,
}

#[derive(Serialize, Debug, oauth1_request::Request)]
struct UploadMediaCommand {
    command: String,
    media_id: String,
}

/// This function returns the OAuth1 Token object from TwitterConfig
fn get_token(config: &TwitterConfig) -> Token {
    oauth1_request::Token::from_parts(
        config.consumer_key.to_string(),
        config.consumer_secret.to_string(),
        config.oauth_token.to_string(),
        config.oauth_token_secret.to_string(),
    )
}

pub async fn generate_media_ids(config: &TwitterConfig, media_attach: &[Attachment]) -> Vec<u64> {
    let mut medias: Vec<u64> = vec![];

    let media_attachments = media_attach.to_owned();
    let mut stream = stream::iter(media_attachments)
        .map(|media| {
            let twitter_config = config.clone();
            tokio::task::spawn(async move {
                match media.r#type {
                    AttachmentType::Image => {
                        upload_simple_media(&twitter_config, &media.url, &media.description).await
                    }
                    AttachmentType::Gifv => {
                        upload_chunk_media(&twitter_config, &media.url, "tweet_gif").await
                    }
                    AttachmentType::Video => {
                        upload_chunk_media(&twitter_config, &media.url, "tweet_video").await
                    }
                    _ => Err::<u64, Box<dyn Error + Send + Sync>>(
                        OolatoocsError::new(&format!(
                            "Cannot treat this type of media: {}",
                            &media.url
                        ))
                        .into(),
                    ),
                }
            })
        })
        .buffered(4);

    while let Some(result) = stream.next().await {
        match result {
            Ok(Ok(v)) => medias.push(v),
            Ok(Err(e)) => warn!("Cannot treat media: {}", e),
            Err(e) => error!("Something went wrong when joining the main thread: {}", e),
        }
    }

    medias
}

/// This function uploads simple images from Mastodon to Twitter and returns the media id from Twitter
async fn upload_simple_media(
    config: &TwitterConfig,
    u: &str,
    d: &Option<String>,
) -> Result<u64, Box<dyn Error + Send + Sync>> {
    // initiate request parameters
    let empty_request = EmptyRequest {}; // Why? Because fuck you, that’s why!
    let token = get_token(config);

    // retrieve the length and bytes stream from the given URL
    let dl = reqwest::get(u).await?;
    let content_length = dl
        .content_length()
        .ok_or(format!("Cannot get content length for {}", u))?;
    let stream = dl.bytes_stream();

    debug!("Ref download URL: {}", u);

    // upload the media
    let client = Client::new();
    let res = client
        .post(TWITTER_UPLOAD_MEDIA_URL)
        .header(
            "Authorization",
            oauth1_request::post(
                TWITTER_UPLOAD_MEDIA_URL,
                &empty_request,
                &token,
                oauth1_request::HMAC_SHA1,
            ),
        )
        .multipart(Form::new().part(
            "media",
            Part::stream_with_length(Body::wrap_stream(stream), content_length),
        ))
        .send()
        .await?
        .json::<UploadMediaResponse>()
        .await?;

    debug!("Media ID: {}", res.media_id);

    // update the metadata
    if let Some(metadata) = d {
        debug!("Metadata found! Processing…");
        metadata_create(config, res.media_id, metadata).await?;
    }

    Ok(res.media_id)
}

/// This function updates the metadata given the current media_id and token
async fn metadata_create(
    config: &TwitterConfig,
    id: u64,
    m: &str,
) -> Result<(), Box<dyn Error + Send + Sync>> {
    let token = get_token(config);
    let empty_request = EmptyRequest {};

    let media_metadata = MediaMetadata {
        media_id: id,
        alt_text: MediaMetadataAltText {
            text: m.to_string(),
        },
    };

    debug!("Metadata to process: {}", m);

    let client = Client::new();
    let metadata = client
        .post(TWITTER_METADATA_MEDIA_URL)
        .header(
            "Authorization",
            oauth1_request::post(
                TWITTER_METADATA_MEDIA_URL,
                &empty_request,
                &token,
                oauth1_request::HMAC_SHA1,
            ),
        )
        .json(&media_metadata)
        .send()
        .await?;

    debug!("Metadata processed with return code: {}", metadata.status());

    Ok(())
}

/// This posts video/gif to Twitter and returns the media id from Twitter
async fn upload_chunk_media(
    config: &TwitterConfig,
    u: &str,
    t: &str,
) -> Result<u64, Box<dyn Error + Send + Sync>> {
    let empty_request = EmptyRequest {};
    let token = get_token(config);

    // retrieve the length, type and bytes stream from the given URL
    let mut dl = reqwest::get(u).await?;
    let content_length = dl
        .content_length()
        .ok_or(format!("Cannot get content length for {}", u))?;
    let content_headers = dl.headers().clone();
    let content_type = content_headers
        .get("Content-Type")
        .ok_or(format!("Cannot get content type for {}", u))?
        .to_str()?;

    debug!("Init the slot for uploading media: {}", u);
    // init the slot for uploading
    let client = Client::new();
    let orig_media_id = client
        .post(TWITTER_UPLOAD_MEDIA_URL)
        .header(
            "Authorization",
            oauth1_request::post(
                TWITTER_UPLOAD_MEDIA_URL,
                &empty_request,
                &token,
                oauth1_request::HMAC_SHA1,
            ),
        )
        .multipart(
            Form::new()
                .text("command", "INIT")
                .text("media_type", content_type.to_owned())
                .text("total_bytes", content_length.to_string())
                .text("media_category", t.to_string()),
        )
        .send()
        .await?
        .json::<UploadMediaResponse>()
        .await?;

    debug!("Slot initiated with ID: {}", orig_media_id.media_id);

    debug!("Appending media to ID: {}", orig_media_id.media_id);
    // append the media to the corresponding slot
    let mut segment: u8 = 0;
    while let Some(chunk) = dl.chunk().await? {
        debug!(
            "Appending segment {} for media ID {}",
            segment, orig_media_id.media_id
        );
        let chunk_size: u64 = chunk.len().try_into().unwrap();
        let res = client
            .post(TWITTER_UPLOAD_MEDIA_URL)
            .header(
                "Authorization",
                oauth1_request::post(
                    TWITTER_UPLOAD_MEDIA_URL,
                    &empty_request,
                    &token,
                    oauth1_request::HMAC_SHA1,
                ),
            )
            .multipart(
                Form::new()
                    .text("command", "APPEND")
                    .text("media_id", orig_media_id.media_id.to_string())
                    .text("segment_index", segment.to_string())
                    .part("media", Part::stream_with_length(chunk, chunk_size)),
            )
            .send()
            .await?;

        if !res.status().is_success() {
            return Err(
                OolatoocsError::new(&format!("Cannot upload part {} of {}", segment, u)).into(),
            );
        }

        segment += 1;
    }

    debug!("Finalize media ID: {}", orig_media_id.media_id);
    // Finalizing task
    let fin = client
        .post(TWITTER_UPLOAD_MEDIA_URL)
        .header(
            "Authorization",
            oauth1_request::post(
                TWITTER_UPLOAD_MEDIA_URL,
                &empty_request,
                &token,
                oauth1_request::HMAC_SHA1,
            ),
        )
        .multipart(
            Form::new()
                .text("command", "FINALIZE")
                .text("media_id", orig_media_id.media_id.to_string()),
        )
        .send()
        .await?
        .json::<UploadMediaResponse>()
        .await?;

    if let Some(p_info) = fin.processing_info {
        if let Some(wait_sec) = p_info.check_after_secs {
            debug!(
                "Processing is not finished yet for ID {}, waiting {} secs",
                orig_media_id.media_id, wait_sec
            );
            // getting here, we have a status and a check_after_secs
            // this status can be anything but we will check it afterwards
            // whatever happens, we can wait here before proceeding
            sleep(Duration::from_secs(wait_sec)).await;

            let command = UploadMediaCommand {
                command: "STATUS".to_string(),
                media_id: orig_media_id.media_id.to_string(),
            };

            loop {
                debug!(
                    "Checking on status for ID {} after waiting {} secs",
                    orig_media_id.media_id, wait_sec
                );

                let status = client
                    .get(TWITTER_UPLOAD_MEDIA_URL)
                    .header(
                        "Authorization",
                        oauth1_request::get(
                            TWITTER_UPLOAD_MEDIA_URL,
                            &command,
                            &token,
                            oauth1_request::HMAC_SHA1,
                        ),
                    )
                    .query(&command)
                    .send()
                    .await?
                    .json::<UploadMediaResponse>()
                    .await?;

                let p_status = status.processing_info.unwrap(); // shouldn’t be None at this point
                match p_status.state {
                    UploadMediaResponseProcessingInfoState::Failed => {
                        debug!("Processing has failed!");
                        return Err(OolatoocsError::new(&format!(
                            "Upload for {} (id: {}) has failed",
                            u, orig_media_id.media_id
                        ))
                        .into());
                    }
                    UploadMediaResponseProcessingInfoState::Succeeded => {
                        debug!("Processing has succeeded, exiting loop!");
                        break;
                    }
                    UploadMediaResponseProcessingInfoState::Pending
                    | UploadMediaResponseProcessingInfoState::InProgress => {
                        debug!(
                            "Processing still pending, waiting {} secs more…",
                            p_status.check_after_secs.unwrap() // unwrap is safe here,
                                                               // check_after_secs is only present
                                                               // when status is pending or in
                                                               // progress
                        );
                        sleep(Duration::from_secs(p_status.check_after_secs.unwrap())).await;
                        continue;
                    }
                }
            }
        }
    }

    Ok(orig_media_id.media_id)
}

pub fn transform_poll(p: &Poll) -> TweetPoll {
    let poll_end_datetime = p.expires_at.unwrap(); // should be safe at this point
    let now = Utc::now();
    let diff = poll_end_datetime.signed_duration_since(now);

    TweetPoll {
        options: p.options.iter().map(|i| i.title.clone()).collect(),
        duration_minutes: diff.num_minutes().try_into().unwrap(), // safe here, number is positive
                                                                  // and can’t be over 21600
    }
}

/// This posts Tweets with all the associated medias
pub async fn post_tweet(
    config: &TwitterConfig,
    content: String,
    medias: Vec<u64>,
    reply_to: Option<u64>,
    poll: Option<TweetPoll>,
) -> Result<u64, Box<dyn Error>> {
    let empty_request = EmptyRequest {}; // Why? Because fuck you, that’s why!
    let token = get_token(config);

    let tweet = Tweet {
        text: content,
        media: medias.is_empty().not().then(|| TweetMediasIds {
            media_ids: medias.iter().map(|m| m.to_string()).collect(),
        }),
        reply: reply_to.map(|s| TweetReply {
            in_reply_to_tweet_id: s.to_string(),
        }),
        poll,
    };

    let client = Client::new();
    let res = client
        .post(TWITTER_API_TWEET_URL)
        .header(
            "Authorization",
            oauth1_request::post(
                TWITTER_API_TWEET_URL,
                &empty_request,
                &token,
                oauth1_request::HMAC_SHA1,
            ),
        )
        .json(&tweet)
        .send()
        .await?
        .json::<TweetResponse>()
        .await?;

    Ok(res.data.id.parse::<u64>().unwrap())
}