package main

import (
	"fmt"
	"io"
	"log"
	"net"
	"net/http"
	"net/url"
	"strconv"
	"strings"
	"time"

	"code.rocket9labs.com/tslocum/bei"
	"code.rocket9labs.com/tslocum/bgammon"
)

type BEIClient struct {
	address    string
	conn       net.Conn
	connected  bool
	terminated bool
	count      int
	replayDir  string
	primary    bool
	quiet      bool
	started    time.Time
}

func NewBEIClient(address string, count int, replayDir string, primary bool, quiet bool) *BEIClient {
	c := &BEIClient{
		address:   address,
		count:     count,
		replayDir: replayDir,
		primary:   primary,
		quiet:     quiet,
		started:   time.Now(),
	}
	return c
}

func (c *BEIClient) REST() bool {
	return strings.HasPrefix(c.address, "http")
}

func (c *BEIClient) restRequest(command string, vars map[string]string) (interface{}, error) {
	if !c.REST() {
		return nil, fmt.Errorf("client is not using a REST connection")
	}
	requestURL := c.address + "/" + command
	if len(vars) > 0 {
		var i int
		for key, value := range vars {
			if i > 0 {
				requestURL += "&"
			}
			requestURL += key + "=" + url.QueryEscape(value)
			i++
		}
	}
	const attempts = 5
	var err error
	for i := 0; i < attempts; i++ {
		if Debug > 0 {
			log.Printf("REQUEST %s", requestURL)
		}

		var r *http.Response
		r, err = httpClient.Get(requestURL)
		if err != nil {
			continue
		}
		defer r.Body.Close()

		body, err := io.ReadAll(r.Body)
		if err != nil {
			continue
		}
		if len(body) == 0 {
			continue
		}
		return bei.DecodeEvent(body)
	}
	return nil, err
}

func (c *BEIClient) Connect() error {
	if c.terminated {
		return nil
	}

	if c.REST() {
		ev, err := c.restRequest(bei.CommandBEI, nil)
		if err != nil {
			return err
		}
		if _, ok := ev.(*bei.EventOkBEI); !ok {
			return fmt.Errorf("unexpected reply from server")
		}
		c.connected = true
		return nil
	}

	conn, err := net.Dial("tcp", c.address)
	if err != nil {
		return err
	}
	c.connected = true
	c.conn = conn

	c.conn.Write([]byte("bei\n"))
	buf, err := c.readLine()
	if err != nil {
		return err
	}
	response, err := bei.DecodeEvent(buf)
	if err != nil {
		return err
	}
	if _, ok := response.(*bei.EventOkBEI); !ok {
		return fmt.Errorf("unexpected reply from server")
	}
	return nil
}

func (c *BEIClient) readLine() ([]byte, error) {
	var buf []byte
	b := make([]byte, 1)
	for {
		n, err := c.conn.Read(b)
		if err != nil {
			return nil, err
		} else if n != 1 {
			return nil, fmt.Errorf("zero read")
		}
		if b[0] == '\n' {
			return buf, nil
		}
		buf = append(buf, b[0])
	}
}

func (c *BEIClient) Double(state []int8) (interface{}, error) {
	if c.terminated {
		return nil, nil
	} else if !c.connected {
		err := c.Connect()
		if err != nil {
			return nil, fmt.Errorf("failed to connect to engine at %s: %s", c.address, err)
		}
	}

	var stateBytes []byte
	for i, v := range state {
		if i > 0 {
			stateBytes = append(stateBytes, ',')
		}
		stateBytes = append(stateBytes, []byte(strconv.Itoa(int(v)))...)
	}

	if c.REST() {
		return c.restRequest(bei.CommandDouble, map[string]string{
			"state": string(stateBytes),
		})
	}

	c.conn.Write([]byte(fmt.Sprintf("double %s\n", stateBytes)))
	buf, err := c.readLine()
	if err != nil {
		return nil, err
	}
	return bei.DecodeEvent(buf)
}

func (c *BEIClient) Move(state []int8) (interface{}, error) {
	if c.terminated {
		return nil, nil
	} else if !c.connected {
		err := c.Connect()
		if err != nil {
			return nil, fmt.Errorf("failed to connect to engine at %s: %s", c.address, err)
		}
	}

	var stateBytes []byte
	for i, v := range state {
		if i > 0 {
			stateBytes = append(stateBytes, ',')
		}
		stateBytes = append(stateBytes, []byte(strconv.Itoa(int(v)))...)
	}

	if c.REST() {
		return c.restRequest(bei.CommandMove, map[string]string{
			"state": string(stateBytes),
		})
	}

	c.conn.Write([]byte(fmt.Sprintf("move %s\n", stateBytes)))
	buf, err := c.readLine()
	if err != nil {
		return nil, err
	}
	return bei.DecodeEvent(buf)
}

func (c *BEIClient) Choose(state []int8) (interface{}, error) {
	if c.terminated {
		return nil, nil
	} else if !c.connected {
		err := c.Connect()
		if err != nil {
			return nil, fmt.Errorf("failed to connect to engine at %s: %s", c.address, err)
		}
	}

	var stateBytes []byte
	for i, v := range state {
		if i > 0 {
			stateBytes = append(stateBytes, ',')
		}
		stateBytes = append(stateBytes, []byte(strconv.Itoa(int(v)))...)
	}

	if c.REST() {
		return c.restRequest(bei.CommandChoose, map[string]string{
			"state": string(stateBytes),
		})
	}

	c.conn.Write([]byte(fmt.Sprintf("choose %s\n", stateBytes)))
	buf, err := c.readLine()
	if err != nil {
		return nil, err
	}
	return bei.DecodeEvent(buf)
}

func beiState(game *bgammon.Game) []int8 {
	// TODO send turn numbers
	var state []int8
	state = append(state, game.Board...)
	state = append(state, game.Roll1, game.Roll2, game.Roll3, 1, 1, game.DoubleValue, game.DoublePlayer, game.Player1.Points, game.Player2.Points, game.Points)
	entered1, entered2 := int8(1), int8(1)
	if game.Variant != bgammon.VariantBackgammon {
		if !game.Player1.Entered {
			entered1 = 0
		}
		if !game.Player2.Entered {
			entered2 = 0
		}
	}
	return append(state, 0, 0, 0, 0, game.Variant, entered1, entered2)
}