package rep

import (
	"encoding/json"
	"net"
	"net/http"
	"strings"
	"sync"
	"time"

	"git.crumpington.com/public/jldb/lib/errs"
	"git.crumpington.com/public/jldb/lib/httpconn"
	"git.crumpington.com/public/jldb/lib/wal"
)

type client struct {
	client *http.Client

	// The following are constant.
	endpoint string
	pskBytes [64]byte
	timeout  time.Duration

	lock sync.Mutex
	conn net.Conn
}

func newClient(endpoint, psk string, timeout time.Duration) *client {
	httpClient := &http.Client{
		Timeout: timeout,
	}

	if !strings.HasSuffix(endpoint, "/") {
		endpoint += "/"
	}

	return &client{
		client:   httpClient,
		endpoint: endpoint,
		pskBytes: pskToBytes(psk),
		timeout:  timeout,
	}
}

func (c *client) GetInfo() (info Info, err error) {
	req, err := http.NewRequest(http.MethodGet, c.endpoint+pathGetInfo, nil)
	if err != nil {
		return info, errs.Unexpected.WithErr(err)
	}
	req.SetBasicAuth("", string(c.pskBytes[:]))

	resp, err := c.client.Do(req)
	if err != nil {
		return info, errs.IO.WithErr(err)
	}
	defer resp.Body.Close()

	if err := json.NewDecoder(resp.Body).Decode(&info); err != nil {
		return info, errs.IO.WithErr(err)
	}
	return info, nil
}

func (c *client) RecvState(recv func(net.Conn) error) error {
	err := c.dialConnect(c.endpoint + pathSendState)
	if err != nil {
		return err
	}
	defer c.conn.Close()

	return recv(c.conn)
}

func (c *client) StreamWAL(w *wal.WAL) error {
	err := c.dialConnect(c.endpoint + pathStreamWAL)
	if err != nil {
		return err
	}
	defer c.conn.Close()

	return w.Recv(c.conn, c.timeout)
}

func (c *client) Close() {
	c.lock.Lock()
	defer c.lock.Unlock()
	if c.conn != nil {
		c.conn.Close()
	}
}

// ----------------------------------------------------------------------------

func (c *client) dialConnect(endpoint string) error {
	conn, err := httpconn.Dial(endpoint)
	if err != nil {
		return err
	}

	conn.SetWriteDeadline(time.Now().Add(c.timeout))
	if _, err := conn.Write(c.pskBytes[:]); err != nil {
		return errs.IO.WithErr(err)
	}

	c.lock.Lock()
	defer c.lock.Unlock()
	c.conn = conn
	return nil
}