//! Sbot type and associated methods.
use async_std::{
    net::TcpStream,
    stream::{Stream, StreamExt},
};
use futures::pin_mut;
use std::collections::HashMap;

use kuska_handshake::async_std::BoxStream;
use kuska_sodiumoxide::crypto::{auth, sign::ed25519};
use kuska_ssb::{
    api::{dto::CreateHistoryStreamIn, ApiCaller},
    discovery, keystore,
    keystore::OwnedIdentity,
    rpc::{RpcReader, RpcWriter},
};

use crate::error::GolgiError;
use crate::messages::{SsbMessageContent, SsbMessageContentType, SsbMessageKVT, SsbMessageValue};
use crate::utils;
use crate::utils::get_source_stream;

// re-export types from kuska
pub use kuska_ssb::api::dto::content::{SubsetQuery, SubsetQueryOptions};

/// A struct representing a connection with a running sbot.
/// A client and an rpc_reader can together be used to make requests to the sbot
/// and read the responses.
/// Note there can be multiple SbotConnection at the same time.
pub struct SbotConnection {
    client: ApiCaller<TcpStream>,
    rpc_reader: RpcReader<TcpStream>,
}

/// The Scuttlebutt identity, keys and configuration parameters for connecting to a local sbot
pub struct Sbot {
    pub id: String,
    public_key: ed25519::PublicKey,
    private_key: ed25519::SecretKey,
    address: String,
    // aka caps key (scuttleverse identifier)
    network_id: auth::Key,
}

impl Sbot {
    /// Initiate a connection with an sbot instance. Define the IP address, port and network key
    /// for the sbot, then retrieve the public key, private key (secret) and identity from the
    /// `.ssb-go/secret` file. Open a TCP stream to the sbot and perform the secret handshake. If successful, create a box stream and split it into a writer and reader. Return RPC handles to the sbot as part of the `struct` output.
    pub async fn init(ip_port: Option<String>, net_id: Option<String>) -> Result<Sbot, GolgiError> {
        let address = if ip_port.is_none() {
            "127.0.0.1:8008".to_string()
        } else {
            ip_port.unwrap()
        };

        let network_id = if net_id.is_none() {
            discovery::ssb_net_id()
        } else {
            auth::Key::from_slice(&hex::decode(net_id.unwrap()).unwrap()).unwrap()
        };

        let OwnedIdentity { pk, sk, id } = keystore::from_gosbot_local()
            .await
            .expect("couldn't read local secret");

        Ok(Self {
            id,
            public_key: pk,
            private_key: sk,
            address,
            network_id,
        })
    }

    /// Creates a new connection with the sbot,
    /// using the address, network_id, public_key and private_key supplied when Sbot was initialized.
    ///
    /// Note that a single Sbot can have multiple SbotConnection at the same time.
    pub async fn get_sbot_connection(&self) -> Result<SbotConnection, GolgiError> {
        let address = self.address.clone();
        let network_id = self.network_id.clone();
        let public_key = self.public_key;
        let private_key = self.private_key.clone();
        Sbot::_get_sbot_connection_helper(address, network_id, public_key, private_key).await
    }

    /// Private helper function which creates a new connection with sbot,
    /// but with all variables passed as arguments.
    async fn _get_sbot_connection_helper(
        address: String,
        network_id: auth::Key,
        public_key: ed25519::PublicKey,
        private_key: ed25519::SecretKey,
    ) -> Result<SbotConnection, GolgiError> {
        let socket = TcpStream::connect(&address)
            .await
            .map_err(|source| GolgiError::Io {
                source,
                context: "socket error; failed to initiate tcp stream connection".to_string(),
            })?;

        let handshake = kuska_handshake::async_std::handshake_client(
            &mut &socket,
            network_id.clone(),
            public_key,
            private_key.clone(),
            public_key,
        )
        .await
        .map_err(GolgiError::Handshake)?;

        let (box_stream_read, box_stream_write) =
            BoxStream::from_handshake(socket.clone(), socket, handshake, 0x8000).split_read_write();

        let rpc_reader = RpcReader::new(box_stream_read);
        let client = ApiCaller::new(RpcWriter::new(box_stream_write));
        let sbot_connection = SbotConnection { rpc_reader, client };
        Ok(sbot_connection)
    }

    /// Call the `partialReplication getSubset` RPC method
    /// and return a Stream of Result<SsbMessageValue, GolgiError>
    ///
    /// # Arguments
    ///
    /// * `query` - A `SubsetQuery` which specifies what filters to use.
    /// * `option` - An Option<`SubsetQueryOptions`> which, if provided, adds additional
    /// specifications to the query, such as specifying page limit and/or descending.
    pub async fn get_subset_stream(
        &mut self,
        query: SubsetQuery,
        options: Option<SubsetQueryOptions>,
    ) -> Result<impl Stream<Item = Result<SsbMessageValue, GolgiError>>, GolgiError> {
        let mut sbot_connection = self.get_sbot_connection().await?;
        let req_id = sbot_connection
            .client
            .getsubset_req_send(query, options)
            .await?;
        let get_subset_stream = get_source_stream(
            sbot_connection.rpc_reader,
            req_id,
            utils::ssb_message_res_parse,
        )
        .await;
        Ok(get_subset_stream)
    }

    /// Call the `whoami` RPC method and return an `id`.
    pub async fn whoami(&mut self) -> Result<String, GolgiError> {
        let mut sbot_connection = self.get_sbot_connection().await?;
        let req_id = sbot_connection.client.whoami_req_send().await?;

        let result = utils::get_async(
            &mut sbot_connection.rpc_reader,
            req_id,
            utils::json_res_parse,
        )
        .await?;

        let id = result
            .get("id")
            .ok_or_else(|| GolgiError::Sbot("id key not found on whoami call".to_string()))?
            .as_str()
            .ok_or_else(|| GolgiError::Sbot("whoami returned non-string value".to_string()))?;
        Ok(id.to_string())
    }

    /// Call the `publish` RPC method and return a message reference.
    ///
    /// # Arguments
    ///
    /// * `msg` - A `SsbMessageContent` `enum` whose variants include `Pub`, `Post`, `Contact`, `About`,
    /// `Channel` and `Vote`. See the `kuska_ssb` documentation for further details such as field
    /// names and accepted values for each variant.
    pub async fn publish(&mut self, msg: SsbMessageContent) -> Result<String, GolgiError> {
        let mut sbot_connection = self.get_sbot_connection().await?;
        let req_id = sbot_connection.client.publish_req_send(msg).await?;

        utils::get_async(
            &mut sbot_connection.rpc_reader,
            req_id,
            utils::string_res_parse,
        )
        .await
    }

    /// Call the `friends follow` RPC method and return a message reference.
    /// if state is true, then sets the following status to true
    /// if state is false, then sets the following status to false (unfollow)
    pub async fn friends_follow(
        &mut self,
        ssb_id: &str,
        state: bool,
    ) -> Result<String, GolgiError> {
        let mut sbot_connection = self.get_sbot_connection().await?;
        let req_id = sbot_connection
            .client
            .friends_follow_req_send(ssb_id, state)
            .await?;
        utils::get_async(
            &mut sbot_connection.rpc_reader,
            req_id,
            utils::string_res_parse,
        )
        .await
    }

    /// Call the `friends isfollowing` RPC method and return a message reference.
    /// returns true if src_id is following dest_id and false otherwise
    pub async fn friends_is_following(
        &mut self,
        src_id: &str,
        dest_id: &str,
    ) -> Result<String, GolgiError> {
        let mut sbot_connection = self.get_sbot_connection().await?;
        let req_id = sbot_connection
            .client
            .friends_isfollowing_req_send(src_id, dest_id)
            .await?;

        utils::get_async(
            &mut sbot_connection.rpc_reader,
            req_id,
            utils::string_res_parse,
        )
        .await
    }

    /// Wrapper for publish which constructs and publishes a post message appropriately from a string.
    ///
    /// # Arguments
    ///
    /// * `text` - A reference to a string slice which represents the text to be published in the post
    pub async fn publish_post(&mut self, text: &str) -> Result<String, GolgiError> {
        let msg = SsbMessageContent::Post {
            text: text.to_string(),
            mentions: None,
        };
        self.publish(msg).await
    }

    /// Wrapper for publish which constructs and publishes an about description message appropriately from a string.
    ///
    /// # Arguments
    ///
    /// * `description` - A reference to a string slice which represents the text to be published as an about description.
    pub async fn publish_description(&mut self, description: &str) -> Result<String, GolgiError> {
        let msg = SsbMessageContent::About {
            about: self.id.to_string(),
            name: None,
            title: None,
            branch: None,
            image: None,
            description: Some(description.to_string()),
            location: None,
            start_datetime: None,
        };
        self.publish(msg).await
    }

    /// Wrapper for publish which constructs and publishes an about name message appropriately from a string.
    ///
    /// # Arguments
    ///
    /// * `name` - A reference to a string slice which represents the text to be published as an about name.
    pub async fn publish_name(&mut self, name: &str) -> Result<String, GolgiError> {
        let msg = SsbMessageContent::About {
            about: self.id.to_string(),
            name: Some(name.to_string()),
            title: None,
            branch: None,
            image: None,
            description: None,
            location: None,
            start_datetime: None,
        };
        self.publish(msg).await
    }

    /// Get the about messages for a particular user in order of recency.
    pub async fn get_about_message_stream(
        &mut self,
        ssb_id: &str,
    ) -> Result<impl Stream<Item = Result<SsbMessageValue, GolgiError>>, GolgiError> {
        let query = SubsetQuery::Author {
            op: "author".to_string(),
            feed: ssb_id.to_string(),
        };
        // specify that most recent messages should be returned first
        let query_options = SubsetQueryOptions {
            descending: Some(true),
            keys: None,
            page_limit: None,
        };
        let get_subset_stream = self.get_subset_stream(query, Some(query_options)).await?;
        // TODO: after fixing sbot regression,
        // change this subset query to filter by type about in addition to author
        // and remove this filter section
        // filter down to about  messages
        let about_message_stream = get_subset_stream.filter(|msg| match msg {
            Ok(val) => val.is_message_type(SsbMessageContentType::About),
            Err(_err) => false,
        });
        // return about message stream
        Ok(about_message_stream)
    }

    /// Get value of latest about message with given key from given user
    pub async fn get_latest_about_message(
        &mut self,
        ssb_id: &str,
        key: &str,
    ) -> Result<Option<String>, GolgiError> {
        // get about_message_stream
        let about_message_stream = self.get_about_message_stream(ssb_id).await?;
        // now we have a stream of about messages with most recent at the front of the vector
        pin_mut!(about_message_stream);
        // iterate through the vector looking for most recent about message with the given key
        let latest_about_message_res: Option<Result<SsbMessageValue, GolgiError>> =
            about_message_stream
                // find the first msg that contains the field `key`
                .find(|res| match res {
                    Ok(msg) => msg.content.get(key).is_some(),
                    Err(_) => false,
                })
                .await;
        // Option<Result<SsbMessageValue, GolgiError>> -> Option<SsbMessageValue>
        let latest_about_message = latest_about_message_res.and_then(|msg| msg.ok());
        // Option<SsbMessageValue> -> Option<String>
        let latest_about_value = latest_about_message.and_then(|msg| {
            msg
                // SsbMessageValue -> Option<&Value>
                .content
                .get(key)
                // Option<&Value> -> <Option<&str>
                .and_then(|value| value.as_str())
                // Option<&str> -> Option<String>
                .map(|value| value.to_string())
        });
        // return value is either `Ok(Some(String))` or `Ok(None)`
        Ok(latest_about_value)
    }

    /// Get HashMap of profile info for given user
    pub async fn get_profile_info(
        &mut self,
        ssb_id: &str,
    ) -> Result<HashMap<String, String>, GolgiError> {
        let mut keys_to_search_for = vec!["name", "description", "image"];
        self.get_about_info(ssb_id, keys_to_search_for).await
    }

    /// Get HashMap of name and image for given user
    /// (this is can be used to display profile images of a list of users)
    pub async fn get_name_and_image(
        &mut self,
        ssb_id: &str,
    ) -> Result<HashMap<String, String>, GolgiError> {
        let mut keys_to_search_for = vec!["name", "image"];
        self.get_about_info(ssb_id, keys_to_search_for).await
    }

    /// Get HashMap of about keys to values for given user
    /// by iteratively searching through a stream of about messages,
    /// in order of recency,
    /// until we find all about messages for all needed info
    /// or reach the end of the stream.
    ///
    /// # Arguments
    ///
    /// * `ssb_id` - A reference to a string slice which represents the id of the user to get info about.
    /// * `keys_to_search_for` - A mutable vector of string slice, which represent the about keys
    /// that will be searched for. As they are found, keys are removed from the vector.
    pub async fn get_about_info(
        &mut self,
        ssb_id: &str,
        mut keys_to_search_for: Vec<&str>,
    ) -> Result<HashMap<String, String>, GolgiError> {
        // get about_message_stream
        let about_message_stream = self.get_about_message_stream(ssb_id).await?;
        // now we have a stream of about messages with most recent at the front of the vector
        pin_mut!(about_message_stream); // needed for iteration
        let mut profile_info: HashMap<String, String> = HashMap::new();
        // iterate through the stream while it still has more values and
        // we still have keys we are looking for
        while let Some(res) = about_message_stream.next().await {
            // if there are no more keys we are looking for, then we are done
            if keys_to_search_for.len() == 0 {
                break;
            }
            // if there are still keys we are looking for, then continue searching
            match res {
                Ok(msg) => {
                    // for each key we are searching for, check if this about
                    // message contains a value for that key
                    for key in &keys_to_search_for.clone() {
                        let option_val = msg
                            .content
                            .get(key)
                            .and_then(|val| val.as_str())
                            .map(|val| val.to_string());
                        match option_val {
                            Some(val) => {
                                // if a value is found, then insert it
                                profile_info.insert(key.to_string(), val);
                                // remove this key fom keys_to_search_for, since we are no longer searching for it
                                keys_to_search_for.retain(|val| val != key)
                            }
                            None => continue,
                        }
                    }
                }
                Err(err) => {
                    // skip errors
                    continue;
                }
            }
        }
        Ok(profile_info)
    }

    /// Get latest about name from given user
    ///
    /// # Arguments
    ///
    /// * `ssb_id` - A reference to a string slice which represents the ssb user
    /// to lookup the about name for.
    pub async fn get_name(&mut self, ssb_id: &str) -> Result<Option<String>, GolgiError> {
        self.get_latest_about_message(ssb_id, "name").await
    }

    /// Get latest about description from given user
    ///
    /// # Arguments
    ///
    /// * `ssb_id` - A reference to a string slice which represents the ssb user
    /// to lookup the about description for.
    pub async fn get_description(&mut self, ssb_id: &str) -> Result<Option<String>, GolgiError> {
        self.get_latest_about_message(ssb_id, "description").await
    }

    /// Call the `createHistoryStream` RPC method
    /// and return a Stream of Result<SsbMessageValue, GolgiError>
    pub async fn create_history_stream(
        &mut self,
        id: String,
    ) -> Result<impl Stream<Item = Result<SsbMessageValue, GolgiError>>, GolgiError> {
        let mut sbot_connection = self.get_sbot_connection().await?;
        let args = CreateHistoryStreamIn::new(id);
        let req_id = sbot_connection
            .client
            .create_history_stream_req_send(&args)
            .await?;
        let history_stream = get_source_stream(
            sbot_connection.rpc_reader,
            req_id,
            utils::ssb_message_res_parse,
        )
        .await;
        Ok(history_stream)
    }
}