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

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;

/// 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
/// instance, as well as handles for calling RPC methods and receiving responses.
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,
    // the primary connection with sbot which can be re-used for non-stream calls
    // note that stream calls will each need their own SbotConnection
    sbot_connection: SbotConnection,
}

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");

        let sbot_connection =
            Sbot::_get_sbot_connection_helper(address.clone(), network_id.clone(), pk, sk.clone())
                .await?;

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

    /// 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<SsbMessageKVT, GolgiError>
    // TODO: add args for `descending` and `page` (max number of msgs in response)
    pub async fn get_subset_stream(
        &mut self,
        query: SubsetQuery,
    ) -> Result<impl Stream<Item = Result<SsbMessageKVT, GolgiError>>, GolgiError> {
        let mut sbot_connection = self.get_sbot_connection().await?;
        let req_id = sbot_connection.client.getsubset_req_send(query).await?;
        let get_subset_stream =
            get_source_stream(sbot_connection.rpc_reader, req_id, utils::kvt_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 req_id = self.sbot_connection.client.whoami_req_send().await?;

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

        let id = result
            .get("id")
            .ok_or(GolgiError::Sbot(
                "id key not found on whoami call".to_string(),
            ))?
            .as_str()
            .ok_or(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 req_id = self.sbot_connection.client.publish_req_send(msg).await?;

        utils::get_async(
            &mut self.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(),
        };
        let get_subset_kvt_stream = self.get_subset_stream(query).await?;
        // map into Stream<Item=Result<SsbMessageValue, GolgiError>>
        let ssb_message_stream = get_subset_kvt_stream.map(|msg| match msg {
            Ok(val) => Ok(val.value),
            Err(err) => Err(err),
        });
        // 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 = ssb_message_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?;
        // TODO: use subset query to order messages instead of doing it this way
        let mut about_messages: Vec<SsbMessageValue> = about_message_stream.try_collect().await?;
        about_messages.sort_by(|a, b| b.timestamp.partial_cmp(&a.timestamp).unwrap());
        // now we have a vector of about messages with most recent at the front of the vector
        // iterate through the vector looking for most recent about message with the given key
        let latest_about = about_messages
            .iter()
            // find the first msg that contains the field `key`
            .find(|msg| msg.content.get(key).is_some())
            // map the found msg (`Some(SsbMessageValue)`) to a `Some(Some(&Value))`
            .map(|msg| msg.content.get(key))
            // flatten `Some(Some(&Value))` into `Some(&Value)`
            .flatten()
            // map `Some(&Value)` to `Some(Some(&str))`
            .map(|msg_val| msg_val.as_str())
            // flatten `Some(Some(&str))` to `Some(&str)`
            .flatten()
            // map `Some(&str))` to `Some(String)`
            .map(|msg_str| msg_str.to_string());

        // return value is either `Ok(Some(String))` or `Ok(None)`
        Ok(latest_about)
    }

    /// 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)
    }
}