use crate::lightwallet::LightWallet;

use std::path::Path;
use std::fs::File;
use std::io;
use std::io::prelude::*;
use std::io::{BufReader, BufWriter};

use std::sync::Arc;
use std::sync::atomic::{AtomicU64, AtomicUsize, Ordering};

use std::error::Error;

use json::{object, JsonValue};

use zcash_primitives::transaction::{TxId, Transaction};
use zcash_primitives::note_encryption::Memo;
use zcash_client_backend::{
    constants::testnet::HRP_SAPLING_PAYMENT_ADDRESS, encoding::encode_payment_address,
};

use futures::Future;
use hyper::client::connect::{Destination, HttpConnector};
use tower_grpc::Request;
use tower_hyper::{client, util};
use tower_util::MakeService;
use futures::stream::Stream;

use crate::grpc_client::{ChainSpec, BlockId, BlockRange, RawTransaction, TransparentAddress, 
                         TransparentAddressBlockFilter, TxFilter, Empty};
use crate::grpc_client::client::CompactTxStreamer;

// Used below to return the grpc "Client" type to calling methods
type Client = crate::grpc_client::client::CompactTxStreamer<tower_request_modifier::RequestModifier<tower_hyper::client::Connection<tower_grpc::BoxBody>, tower_grpc::BoxBody>>;

pub struct LightClient {
    pub wallet          : Arc<LightWallet>,
    pub sapling_output  : Vec<u8>,
    pub sapling_spend   : Vec<u8>,
}

impl LightClient {

    pub fn set_wallet_initial_state(&self) {
        self.wallet.set_initial_block(500000,
                "004fada8d4dbc5e80b13522d2c6bd0116113c9b7197f0c6be69bc7a62f2824cd",
                "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");

    }

    pub fn new(seed_phrase: Option<&str>) -> io::Result<Self> {
        let mut lc = if Path::new("wallet.dat").exists() {
            // Make sure that if a wallet exists, there is no seed phrase being attempted
            if !seed_phrase.is_none() {
                return Err(io::Error::new(io::ErrorKind::AlreadyExists,
                    "Cannot create a new wallet from seed, because a wallet already exists"));
            }

            let mut file_buffer = BufReader::new(File::open("wallet.dat")?);
            
            let wallet = LightWallet::read(&mut file_buffer)?;
             LightClient {
                wallet          : Arc::new(wallet), 
                sapling_output  : vec![], 
                sapling_spend   : vec![]
            }
        } else {
            let l = LightClient {
                wallet          : Arc::new(LightWallet::new(seed_phrase)?), 
                sapling_output  : vec![], 
                sapling_spend   : vec![]
            };

            l.set_wallet_initial_state();

            l
        };
        
        // Read Sapling Params
        let mut f = File::open("/home/adityapk/.zcash-params/sapling-output.params")?;
        f.read_to_end(&mut lc.sapling_output)?;
        let mut f = File::open("/home/adityapk/.zcash-params/sapling-spend.params")?;
        f.read_to_end(&mut lc.sapling_spend)?;

        Ok(lc)
    }

    pub fn last_scanned_height(&self) -> u64 {
        self.wallet.last_scanned_height() as u64
    }

    pub fn do_address(&self) -> json::JsonValue {       
        // Collect z addresses
        let z_addresses = self.wallet.address.iter().map( |ad| {
            let address = encode_payment_address(HRP_SAPLING_PAYMENT_ADDRESS, &ad);
            object!{
                "address" => address.clone(),
                "balance" => self.wallet.balance(Some(address.clone())),
                "verified_balance" => self.wallet.verified_balance(Some(address)),
            }
        }).collect::<Vec<JsonValue>>();

        // Collect t addresses
        let t_addresses = self.wallet.tkeys.iter().map( |sk| {
            let address = LightWallet::address_from_sk(&sk);

            // Get the balance for this address
            let balance = self.wallet.tbalance(Some(address.clone()));
            
            object!{
                "address" => address,
                "balance" => balance,
            }
        }).collect::<Vec<JsonValue>>();

        object!{
            "balance"           => self.wallet.balance(None),
            "verified_balance"  => self.wallet.verified_balance(None),
            "z_addresses"       => z_addresses,
            "t_addresses"       => t_addresses,
        }
    }

    pub fn do_save(&self) {
        print!("Saving wallet...");
        io::stdout().flush().ok().expect("Could not flush stdout");
        let mut file_buffer = BufWriter::with_capacity(
            1_000_000, // 1 MB write buffer
            File::create("wallet.dat").unwrap());
        
        self.wallet.write(&mut file_buffer).unwrap();
        println!("[OK]");
    }


    pub fn do_info(&self) {
        let uri: http::Uri = format!("http://127.0.0.1:9067").parse().unwrap();

        let say_hello = self.make_grpc_client(uri).unwrap()
            .and_then(move |mut client| {
                client.get_lightd_info(Request::new(Empty{}))
            })
            .and_then(move |response| {
                //let tx = Transaction::read(&response.into_inner().data[..]).unwrap();
                println!("{:?}", response.into_inner());

                Ok(())
            })
            .map_err(|e| {
                println!("ERR = {:?}", e);
            });

        tokio::runtime::current_thread::Runtime::new().unwrap().block_on(say_hello).unwrap()
    }

    pub fn do_seed_phrase(&self) -> String {
        self.wallet.get_seed_phrase()
    }

    // Return a list of all notes, spent and unspent
    pub fn do_list_notes(&self, all_notes: bool) -> JsonValue {
        let mut unspent_notes: Vec<JsonValue> = vec![];
        let mut spent_notes  : Vec<JsonValue> = vec![];
        let mut pending_notes: Vec<JsonValue> = vec![];

        // Collect Sapling notes
        self.wallet.txs.read().unwrap().iter()
            .flat_map( |(txid, wtx)| {
                wtx.notes.iter().filter_map(move |nd| 
                    if !all_notes && nd.spent.is_some() {
                        None
                    } else {
                        Some(object!{
                            "created_in_block"   => wtx.block,
                            "created_in_txid"    => format!("{}", txid),
                            "value"              => nd.note.value,
                            "is_change"          => nd.is_change,
                            "address"            => LightWallet::address_from_extfvk(&nd.extfvk, nd.diversifier),
                            "spent"              => nd.spent.map(|spent_txid| format!("{}", spent_txid)),
                            "unconfirmed_spent"  => nd.unconfirmed_spent.map(|spent_txid| format!("{}", spent_txid)),
                        })
                    }
                )
            })
            .for_each( |note| {
                if note["spent"].is_null() && note["unconfirmed_spent"].is_null() {
                    unspent_notes.push(note);
                } else if !note["spent"].is_null() {
                    spent_notes.push(note);
                } else {
                    pending_notes.push(note);
                }
            });
        
        // Collect UTXOs
        let utxos = self.wallet.utxos.read().unwrap().iter()
            .map(|utxo| {
                object!{
                    "created_in_block"   => utxo.height,
                    "created_in_txid"    => format!("{}", utxo.txid),
                    "value"              => utxo.value,
                    "scriptkey"          => hex::encode(utxo.script.clone()),
                    "is_change"          => false,  // TODO: Identify notes as change
                    "address"            => utxo.address.clone(),
                    "spent"              => utxo.spent.map(|spent_txid| format!("{}", spent_txid)),
                    "unconfirmed_spent"  => utxo.unconfirmed_spent.map(|spent_txid| format!("{}", spent_txid)),
                }
            })
            .collect::<Vec<JsonValue>>();

        let mut res = object!{
            "unspent_notes" => unspent_notes,
            "pending_notes" => pending_notes,
            "utxos"         => utxos,
        };

        if all_notes {
            res["spent_notes"] = JsonValue::Array(spent_notes);
        }

        res
    }

    pub fn do_list_transactions(&self) -> JsonValue {
        // Create a list of TransactionItems
        let mut tx_list = self.wallet.txs.read().unwrap().iter()
            .flat_map(| (_k, v) | {
                let mut txns: Vec<JsonValue> = vec![];

                if v.total_shielded_value_spent > 0 {
                    // If money was spent, create a transaction. For this, we'll subtract
                    // all the change notes. TODO: Add transparent change here to subtract it also
                    let total_change: u64 = v.notes.iter()
                        .filter( |nd| nd.is_change )
                        .map( |nd| nd.note.value )
                        .sum();

                    // TODO: What happens if change is > than sent ?

                    txns.push(object! {
                        "block_height" => v.block,
                        "txid"         => format!("{}", v.txid),
                        "amount"       => total_change as i64 
                                            - v.total_shielded_value_spent as i64 
                                            - v.total_transparent_value_spent as i64,
                        "address"      => None::<String>, // TODO: For send, we don't have an address
                        "memo"         => None::<String>
                    });
                } 

                // For each sapling note that is not a change, add a Tx.
                txns.extend(v.notes.iter()
                    .filter( |nd| !nd.is_change )
                    .map ( |nd| 
                        object! {
                            "block_height" => v.block,
                            "txid"         => format!("{}", v.txid),
                            "amount"       => nd.note.value as i64,
                            "address"      => nd.note_address().unwrap(),
                            "memo"         => match &nd.memo {
                                                Some(memo) => {
                                                    match memo.to_utf8() {
                                                        Some(Ok(memo_str)) => Some(memo_str),
                                                        _ => None
                                                    }
                                                }
                                                _ => None
                                            }
                    })
                );

                // Get the total transparent recieved
                let total_transparent_received = v.utxos.iter().map(|u| u.value).sum::<u64>();
                if total_transparent_received > v.total_transparent_value_spent {
                    // Create a input transaction for the transparent value as well.
                    txns.push(object!{
                        "block_height" => v.block,
                        "txid"         => format!("{}", v.txid),
                        "amount"       => total_transparent_received as i64 - v.total_transparent_value_spent as i64,
                        "address"      => v.utxos.iter().map(|u| u.address.clone()).collect::<Vec<String>>().join(","),
                        "memo"         => None::<String>
                    })
                }

                txns
            })
            .collect::<Vec<JsonValue>>();

        tx_list.sort_by( |a, b| if a["block_height"] == b["block_height"] {
                                    a["txid"].as_str().cmp(&b["txid"].as_str())
                                } else {
                                    a["block_height"].as_i32().cmp(&b["block_height"].as_i32())
                                }
        );

        JsonValue::Array(tx_list)
    }

    pub fn do_rescan(&self) {
        // First, clear the state from the wallet
        self.wallet.clear_blocks();

        // Then set the inital block
        self.set_wallet_initial_state();

        // Then, do a sync, which will force a full rescan from the initial state
        self.do_sync();
    }

    pub fn do_sync(&self) {
        // Sync is 3 parts
        // 1. Get the latest block
        // 2. Get all the blocks that we don't have
        // 3. Find all new Txns that don't have the full Tx, and get them as full transactions 
        //    and scan them, mainly to get the memos
        let mut last_scanned_height = self.wallet.last_scanned_height() as u64;
        let mut end_height = last_scanned_height + 1000;

        // This will hold the latest block fetched from the RPC
        let latest_block_height = Arc::new(AtomicU64::new(0));
        // TODO: this could be a oneshot channel
        let latest_block_height_clone = latest_block_height.clone();
        self.fetch_latest_block(move |block: BlockId| {
                latest_block_height_clone.store(block.height, Ordering::SeqCst);
            });
        let last_block = latest_block_height.load(Ordering::SeqCst);

        let bytes_downloaded = Arc::new(AtomicUsize::new(0));

        // Fetch CompactBlocks in increments
        loop {
            let local_light_wallet = self.wallet.clone();
            let local_bytes_downloaded = bytes_downloaded.clone();

            print!("Syncing {}/{}, Balance = {}           \r", 
                last_scanned_height, last_block, self.wallet.balance(None));

            // Fetch compact blocks
            self.fetch_blocks(last_scanned_height, end_height, 
                move |encoded_block: &[u8]| {
                    local_light_wallet.scan_block(encoded_block);
                    local_bytes_downloaded.fetch_add(encoded_block.len(), Ordering::SeqCst);
            });

            // We'll also fetch all the txids that our transparent addresses are involved with
            // TODO: Use for all t addresses
            let address = LightWallet::address_from_sk(&self.wallet.tkeys[0]);
            let wallet = self.wallet.clone();
            self.fetch_transparent_txids(address, last_scanned_height, end_height, 
                move |tx_bytes: &[u8] | {
                    let tx = Transaction::read(tx_bytes).unwrap();

                    // Scan this Tx for transparent inputs and outputs
                    wallet.scan_full_tx(&tx, -1);   // TODO: Add the height here!
                }
            );
            
            last_scanned_height = end_height + 1;
            end_height = last_scanned_height + 1000 - 1;

            if last_scanned_height > last_block {
                break;
            } else if end_height > last_block {
                end_height = last_block;
            }        
        }    
        
        println!("Synced to {}, Downloaded {} kB                               \r", 
                last_block, bytes_downloaded.load(Ordering::SeqCst) / 1024);

        
        // Get the Raw transaction for all the wallet transactions

        // We need to first copy over the Txids from the wallet struct, because
        // we need to free the read lock from here (Because we'll self.wallet.txs later)
        let txids_to_fetch: Vec<(TxId, i32)>;
        {
            // First, build a list of all the TxIDs and Memos that we need 
            // to fetch. 
            // 1. Get all (txid, Option<Memo>)
            // 2. Filter out all txids where the Memo is None 
            //     (Which means that particular txid was never fetched. Remember
            //      that when memos are fetched, if they are empty, they become 
            //      Some(f60000...)
            let txids_and_memos = self.wallet.txs.read().unwrap().iter()
                .flat_map( |(txid, wtx)| {  // flat_map because we're collecting vector of vectors
                    wtx.notes.iter()
                        .filter( |nd| nd.memo.is_none())                // only get if memo is None (i.e., it has not been fetched)
                        .map( |nd| (txid.clone(), nd.memo.clone(), wtx.block) )    // collect (txid, memo, height) Clone everything because we want copies, so we can release the read lock
                        .collect::<Vec<(TxId, Option<Memo>, i32)>>()         // convert to vector
                })
                .collect::<Vec<(TxId, Option<Memo>, i32)>>();
                
            //println!("{:?}", txids_and_memos);
            // TODO: Assert that all the memos here are None

            txids_to_fetch = txids_and_memos.iter()
                .map( | (txid, _, h) | (txid.clone(), *h) )  // We're only interested in the txids, so drop the Memo, which is None anyway
                .collect::<Vec<(TxId, i32)>>();            // and convert into Vec
        }

        // And go and fetch the txids, getting the full transaction, so we can 
        // read the memos        
        for (txid, height) in txids_to_fetch {
            let light_wallet_clone = self.wallet.clone();
            println!("Fetching full Tx: {}", txid);

            self.fetch_full_tx(txid, move |tx_bytes: &[u8] | {
                let tx = Transaction::read(tx_bytes).unwrap();

                light_wallet_clone.scan_full_tx(&tx, height);
            });
        };

        // Finally, fetch the UTXOs

        // Get all the UTXOs for our transparent addresses, clearing out the current list
        self.wallet.clear_utxos();
        // Fetch UTXOs
        self.wallet.tkeys.iter()
            .map( |sk| LightWallet::address_from_sk(&sk))
            .for_each( |taddr| {
                let wallet = self.wallet.clone();
                self.fetch_utxos(taddr, move |utxo| {
                   wallet.add_utxo(&utxo);
                });
            });
    }

    pub fn do_send(&self, addr: &str, value: u64, memo: Option<String>) {
        let rawtx = self.wallet.send_to_address(
            u32::from_str_radix("2bb40e60", 16).unwrap(),   // Blossom ID
            &self.sapling_spend, &self.sapling_output,
            &addr, value, memo
        );
        
        match rawtx {
            Some(txbytes)   => self.broadcast_raw_tx(txbytes),
            None            => eprintln!("No Tx to broadcast")
        };
    }

    pub fn fetch_blocks<F : 'static + std::marker::Send>(&self, start_height: u64, end_height: u64, c: F)
        where F : Fn(&[u8]) {
        // Fetch blocks
        let uri: http::Uri = format!("http://127.0.0.1:9067").parse().unwrap();

        let dst = Destination::try_from_uri(uri.clone()).unwrap();
        let connector = util::Connector::new(HttpConnector::new(4));
        let settings = client::Builder::new().http2_only(true).clone();
        let mut make_client = client::Connect::with_builder(connector, settings);

        let say_hello = make_client
            .make_service(dst)
            .map_err(|e| panic!("connect error: {:?}", e))
            .and_then(move |conn| {

                let conn = tower_request_modifier::Builder::new()
                    .set_origin(uri)
                    .build(conn)
                    .unwrap();

                // Wait until the client is ready...
                CompactTxStreamer::new(conn)
                    .ready()
                    .map_err(|e| eprintln!("streaming error {:?}", e))
            })
            .and_then(move |mut client| {
                let bs = BlockId{ height: start_height, hash: vec!()};
                let be = BlockId{ height: end_height,   hash: vec!()};

                let br = Request::new(BlockRange{ start: Some(bs), end: Some(be)});
                client
                    .get_block_range(br)
                    .map_err(|e| {
                        eprintln!("RouteChat request failed; err={:?}", e);
                    })
                    .and_then(move |response| {
                        let inbound = response.into_inner();
                        inbound.for_each(move |b| {
                            use prost::Message;
                            let mut encoded_buf = vec![];

                            b.encode(&mut encoded_buf).unwrap();
                            c(&encoded_buf);

                            Ok(())
                        })
                        .map_err(|e| eprintln!("gRPC inbound stream error: {:?}", e))                    
                    })
            });

        tokio::runtime::current_thread::Runtime::new().unwrap().block_on(say_hello).unwrap();
    }

    pub fn fetch_utxos<F : 'static + std::marker::Send>(&self, address: String, c: F)
            where F : Fn(crate::lightwallet::Utxo) {
        let uri: http::Uri = format!("http://127.0.0.1:9067").parse().unwrap();

        let dst = Destination::try_from_uri(uri.clone()).unwrap();
        let connector = util::Connector::new(HttpConnector::new(4));
        let settings = client::Builder::new().http2_only(true).clone();
        let mut make_client = client::Connect::with_builder(connector, settings);

        let say_hello = make_client
            .make_service(dst)
            .map_err(|e| panic!("connect error: {:?}", e))
            .and_then(move |conn| {

                let conn = tower_request_modifier::Builder::new()
                    .set_origin(uri)
                    .build(conn)
                    .unwrap();

                // Wait until the client is ready...
                CompactTxStreamer::new(conn)
                    .ready()
                    .map_err(|e| eprintln!("streaming error {:?}", e))
            })
            .and_then(move |mut client| {

                let br = Request::new(TransparentAddress{ address });
                client
                    .get_utxos(br)
                    .map_err(|e| {
                        eprintln!("RouteChat request failed; err={:?}", e);
                    })
                    .and_then(move |response| {
                        let inbound = response.into_inner();
                        inbound.for_each(move |b| {
                            let mut txid_bytes = [0u8; 32];
                            txid_bytes.copy_from_slice(&b.txid);

                            let u = crate::lightwallet::Utxo {
                                address: b.address.unwrap().address,
                                txid: TxId {0: txid_bytes},
                                output_index: b.output_index,
                                script: b.script.to_vec(),
                                height: b.height as i32,
                                value: b.value,
                                spent: None,
                                unconfirmed_spent: None,
                            };

                            c(u);

                            Ok(())
                        })
                        .map_err(|e| eprintln!("gRPC inbound stream error: {:?}", e))                    
                    })
            });

        tokio::runtime::current_thread::Runtime::new().unwrap().block_on(say_hello).unwrap();
    }

    pub fn fetch_transparent_txids<F : 'static + std::marker::Send>(&self, address: String, 
        start_height: u64, end_height: u64,c: F)
            where F : Fn(&[u8]) {
        let uri: http::Uri = format!("http://127.0.0.1:9067").parse().unwrap();

        let dst = Destination::try_from_uri(uri.clone()).unwrap();
        let connector = util::Connector::new(HttpConnector::new(4));
        let settings = client::Builder::new().http2_only(true).clone();
        let mut make_client = client::Connect::with_builder(connector, settings);

        let say_hello = make_client
            .make_service(dst)
            .map_err(|e| panic!("connect error: {:?}", e))
            .and_then(move |conn| {

                let conn = tower_request_modifier::Builder::new()
                    .set_origin(uri)
                    .build(conn)
                    .unwrap();

                // Wait until the client is ready...
                CompactTxStreamer::new(conn)
                    .ready()
                    .map_err(|e| eprintln!("streaming error {:?}", e))
            })
            .and_then(move |mut client| {
                let start = Some(BlockId{ height: start_height, hash: vec!()});
                let end   = Some(BlockId{ height: end_height,   hash: vec!()});

                let br = Request::new(TransparentAddressBlockFilter{ address, range: Some(BlockRange{start, end}) });

                client
                    .get_address_txids(br)
                    .map_err(|e| {
                        eprintln!("RouteChat request failed; err={:?}", e);
                    })
                    .and_then(move |response| {
                        let inbound = response.into_inner();
                        inbound.for_each(move |tx| {
                            //let tx = Transaction::read(&tx.into_inner().data[..]).unwrap();
                            c(&tx.data);

                            Ok(())
                        })
                        .map_err(|e| eprintln!("gRPC inbound stream error: {:?}", e))                    
                    })
            });

        tokio::runtime::current_thread::Runtime::new().unwrap().block_on(say_hello).unwrap();
    }

    pub fn fetch_full_tx<F : 'static + std::marker::Send>(&self, txid: TxId, c: F)
            where F : Fn(&[u8]) {
        let uri: http::Uri = format!("http://127.0.0.1:9067").parse().unwrap();

        let say_hello = self.make_grpc_client(uri).unwrap()
            .and_then(move |mut client| {
                let txfilter = TxFilter { block: None, index: 0, hash: txid.0.to_vec() };
                client.get_transaction(Request::new(txfilter))
            })
            .and_then(move |response| {
                //let tx = Transaction::read(&response.into_inner().data[..]).unwrap();
                c(&response.into_inner().data);

                Ok(())
            })
            .map_err(|e| {
                println!("ERR = {:?}", e);
            });

        tokio::runtime::current_thread::Runtime::new().unwrap().block_on(say_hello).unwrap()
    }

    pub fn broadcast_raw_tx(&self, tx_bytes: Box<[u8]>) {
        let uri: http::Uri = format!("http://127.0.0.1:9067").parse().unwrap();

        let say_hello = self.make_grpc_client(uri).unwrap()
            .and_then(move |mut client| {
                client.send_transaction(Request::new(RawTransaction {data: tx_bytes.to_vec()}))
            })
            .and_then(move |response| {
                println!("{:?}", response.into_inner());
                Ok(())
            })
            .map_err(|e| {
                println!("ERR = {:?}", e);
            });

        tokio::runtime::current_thread::Runtime::new().unwrap().block_on(say_hello).unwrap()
    }

    pub fn fetch_latest_block<F : 'static + std::marker::Send>(&self, mut c : F) 
        where F : FnMut(BlockId) {
        let uri: http::Uri = format!("http://127.0.0.1:9067").parse().unwrap();

        let say_hello = self.make_grpc_client(uri).unwrap()
            .and_then(|mut client| {
                client.get_latest_block(Request::new(ChainSpec {}))
            })
            .and_then(move |response| {
                c(response.into_inner());
                Ok(())
            })
            .map_err(|e| {
                println!("ERR = {:?}", e);
            });

        tokio::runtime::current_thread::Runtime::new().unwrap().block_on(say_hello).unwrap()
    }
    
    fn make_grpc_client(&self, uri: http::Uri) -> Result<Box<dyn Future<Item=Client, Error=tower_grpc::Status> + Send>, Box<dyn Error>> {
        let dst = Destination::try_from_uri(uri.clone())?;
        let connector = util::Connector::new(HttpConnector::new(4));
        let settings = client::Builder::new().http2_only(true).clone();
        let mut make_client = client::Connect::with_builder(connector, settings);

        let say_hello = make_client
            .make_service(dst)
            .map_err(|e| panic!("connect error: {:?}", e))
            .and_then(move |conn| {

                let conn = tower_request_modifier::Builder::new()
                    .set_origin(uri)
                    .build(conn)
                    .unwrap();

                // Wait until the client is ready...
                CompactTxStreamer::new(conn).ready()
            });
        Ok(Box::new(say_hello))
    }
}





/*
 TLS Example https://gist.github.com/kiratp/dfcbcf0aa713a277d5d53b06d9db9308
 
// [dependencies]
// futures = "0.1.27"
// http = "0.1.17"
// tokio = "0.1.21"
// tower-request-modifier = { git = "https://github.com/tower-rs/tower-http" }
// tower-grpc = { version = "0.1.0", features = ["tower-hyper"] }
// tower-service = "0.2"
// tower-util = "0.1"
// tokio-rustls = "0.10.0-alpha.3"
// webpki = "0.19.1"
// webpki-roots = "0.16.0"
// tower-h2 = { git = "https://github.com/tower-rs/tower-h2" }
// openssl = "*"
// openssl-probe = "*"

use std::thread;
use std::sync::{Arc};
use futures::{future, Future};
use tower_util::MakeService;

use tokio_rustls::client::TlsStream;
use tokio_rustls::{rustls::ClientConfig, TlsConnector};
use std::net::SocketAddr;

use tokio::executor::DefaultExecutor;
use tokio::net::tcp::TcpStream;
use tower_h2;

use std::net::ToSocketAddrs;



struct Dst(SocketAddr);


impl tower_service::Service<()> for Dst {
    type Response = TlsStream<TcpStream>;
    type Error = ::std::io::Error;
    type Future = Box<dyn Future<Item = TlsStream<TcpStream>, Error = ::std::io::Error> + Send>;

    fn poll_ready(&mut self) -> futures::Poll<(), Self::Error> {
        Ok(().into())
    }

    fn call(&mut self, _: ()) -> Self::Future {
        println!("{:?}", self.0);
        let mut config = ClientConfig::new();

        config.alpn_protocols.push(b"h2".to_vec());
        config.root_store.add_server_trust_anchors(&webpki_roots::TLS_SERVER_ROOTS);
        let config = Arc::new(config);
        let tls_connector = TlsConnector::from(config);

        let addr_string_local = "mydomain.com";

        let domain = webpki::DNSNameRef::try_from_ascii_str(addr_string_local).unwrap();
        let domain_local = domain.to_owned();

        let stream = TcpStream::connect(&self.0).and_then(move |sock| {
            sock.set_nodelay(true).unwrap();
            tls_connector.connect(domain_local.as_ref(), sock)
        })
        .map(move |tcp| tcp);

        Box::new(stream)
    }
}

// Same implementation but without TLS. Should make it straightforward to run without TLS
// when testing on local machine

// impl tower_service::Service<()> for Dst {
//     type Response = TcpStream;
//     type Error = ::std::io::Error;
//     type Future = Box<dyn Future<Item = TcpStream, Error = ::std::io::Error> + Send>;

//     fn poll_ready(&mut self) -> futures::Poll<(), Self::Error> {
//         Ok(().into())
//     }

//     fn call(&mut self, _: ()) -> Self::Future {
//         let mut config = ClientConfig::new();
//         config.alpn_protocols.push(b"h2".to_vec());
//         config.root_store.add_server_trust_anchors(&webpki_roots::TLS_SERVER_ROOTS);

//         let addr_string_local = "mydomain.com".to_string();
//         let addr = addr_string_local.as_str();
        
//         let stream = TcpStream::connect(&self.0)
//             .and_then(move |sock| {
//                 sock.set_nodelay(true).unwrap();
//                 Ok(sock)
//             });
//         Box::new(stream)
//     }
// }


fn connect() {
    let keepalive = future::loop_fn((), move |_| {
        let uri: http::Uri = "https://mydomain.com".parse().unwrap();
        println!("Connecting to network at: {:?}", uri);

        let addr = "https://mydomain.com:443"
            .to_socket_addrs()
            .unwrap()
            .next()
            .unwrap();

        let h2_settings = Default::default();
        let mut make_client = tower_h2::client::Connect::new(Dst {0: addr}, h2_settings, DefaultExecutor::current());

        make_client
            .make_service(())
            .map_err(|e| {
                eprintln!("HTTP/2 connection failed; err={:?}", e);
            })
            .and_then(move |conn| {
                let conn = tower_request_modifier::Builder::new()
                    .set_origin(uri)
                    .build(conn)
                    .unwrap();

                MyGrpcService::new(conn)
                    // Wait until the client is ready...
                    .ready()
                    .map_err(|e| eprintln!("client closed: {:?}", e))
            })
            .and_then(move |mut client| {
                // do stuff
            })
            .then(|e| {
                eprintln!("Reopening client connection to network: {:?}", e);
                let retry_sleep = std::time::Duration::from_secs(1);

                thread::sleep(retry_sleep);
                Ok(future::Loop::Continue(()))
            })
    });

    thread::spawn(move || tokio::run(keepalive));
}

pub fn main() {
    connect();
}

 */