package cli

import (
	"context"
	"encoding/json"
	"fmt"
	"git.nspix.com/golang/micro/helper/pool/bytepool"
	"git.nspix.com/golang/micro/helper/utils"
	"git.nspix.com/golang/micro/log"
	"net"
	"os"
	"path"
	"runtime"
	"strings"
	"sync"
	"sync/atomic"
	"time"
)

const (
	MaxReadBufferLength = 64 * 1024

	EOL = "\n"
)

type HandleFunc func(ctx *Context) (err error)

type Middleware func(next HandleFunc) HandleFunc

type (
	Options struct {
		Usage       string
		Description string
		Middleware  []Middleware
	}

	Option func(o *Options)
)

type Server struct {
	seq        int32
	ctx        context.Context
	locker     sync.RWMutex
	executor   *Executor
	contextMap map[int32]*Context
}

func WithUsage(usage string) Option {
	return func(o *Options) {
		o.Usage = usage
	}
}

func WithDescription(desc string) Option {
	return func(o *Options) {
		o.Description = desc
	}
}

func WithMiddleware(ms ...Middleware) Option {
	return func(o *Options) {
		if o.Middleware == nil {
			o.Middleware = make([]Middleware, 0)
		}
		o.Middleware = append(o.Middleware, ms...)
	}
}

func (svr *Server) writePack(conn net.Conn, packet *Frame) (err error) {
	if packet.Timestamp == 0 {
		packet.Timestamp = time.Now().Unix()
	}
	err = writeFrame(conn, packet)
	return
}

func (svr *Server) process(id int32, conn net.Conn) (err error) {
	var (
		buf []byte
		res *Response
	)
	buffer := bytepool.Get(MaxReadBufferLength)
	defer func() {
		bytepool.Put(buffer)
		svr.locker.Lock()
		delete(svr.contextMap, id)
		svr.locker.Unlock()
		err = conn.Close()
		if v := recover(); v != nil {
			log.Errorf("handle %d command failed cause by %v", id, v)
		}
	}()
	for {
		reqPacket := &Frame{}
		if reqPacket, err = readFrame(conn); err != nil {
			break
		}
		switch reqPacket.Type {
		case PacketTypeCompleter:
			tokens := strings.Fields(strings.ToLower(strings.TrimSpace(string(reqPacket.Data))))
			cs := svr.executor.Completer(tokens...)
			if buf, err = json.Marshal(cs); err == nil {
				err = svr.writePack(conn, &Frame{Type: PacketTypeCompleter, Data: buf})
			}
		case PacketTypeEcho:
			vs := make(map[string]string)
			vs["os"] = runtime.GOOS
			vs["cid"] = fmt.Sprint(id)
			vs["login_at"] = time.Now().Format(time.RFC822)
			vs["client_addr"] = conn.RemoteAddr().String()
			vs["name"] = os.Getenv("MICRO_SERVICE_NAME")
			vs["version"] = os.Getenv("MICRO_SERVICE_VERSION")
			if buf, err = json.Marshal(vs); err == nil {
				err = svr.writePack(conn, &Frame{Type: PacketTypeEcho, Data: buf})
			}
		case PacketTypeData:
			var (
				ok  bool
				ctx *Context
			)
			tokens := strings.Fields(strings.TrimSpace(string(reqPacket.Data)))
			svr.locker.Lock()
			if ctx, ok = svr.contextMap[id]; !ok {
				ctx = &Context{
					ID: id,
				}
				ctx.Set("ID", id)
				svr.contextMap[id] = ctx
			}
			svr.locker.Unlock()
			ctx.WithContext(svr.ctx)
			ctx.reset(strings.TrimSpace(string(reqPacket.Data)))
			if res, err = svr.executor.Do(ctx, tokens...); err == nil {
				if res.Code == 0 {
					err = svr.writePack(conn, &Frame{Type: PacketTypeData, Data: res.Data})
				} else {
					err = svr.writePack(conn, &Frame{Type: PacketTypeData, Error: fmt.Sprintf("ERROR %d: %s", res.Code, res.Error)})
				}
			} else {
				err = svr.writePack(conn, &Frame{Type: PacketTypeData, Error: fmt.Sprintf("ERROR 5000: %s", err.Error())})
			}
		default:
			return
		}
	}
	return
}

func (svr *Server) formatDescription(ss ...string) (usage string, description string) {
	for _, s := range ss {
		if strings.HasPrefix(s, ":") {
			usage += "{" + s[1:] + "} "
		} else {
			usage += s + " "
			description += s + " "
		}
	}
	return
}

func (svr *Server) NotFoundHandle(cb HandleFunc) {
	svr.executor.NotFoundHandle = cb
}

func (svr *Server) Handle(path string, cb HandleFunc, cbs ...Option) {
	var (
		err    error
		length int
		p      *Executor
		q      *Executor
		pFlag  int32
	)
	var tokens []string
	if strings.HasPrefix(path, "/") {
		tokens = strings.Split(path[1:], "/")
	} else {
		tokens = utils.BreakUp(path)
	}
	opts := &Options{}
	for _, o := range cbs {
		o(opts)
	}
	if opts.Usage == "" && opts.Description == "" {
		opts.Usage, opts.Description = svr.formatDescription(tokens...)
	}
	svr.locker.Lock()
	defer svr.locker.Unlock()
	length = len(tokens)
	p = svr.executor
	for i, token := range tokens {
		token = strings.TrimSpace(strings.ToLower(token))
		if token == "" {
			continue
		}
		if atomic.LoadInt32(&pFlag) == 1 {
			if !strings.HasPrefix(token, ":") {
				panic(fmt.Sprintf("param %s must begin with :", token))
			}
		}
		if strings.HasPrefix(token, ":") {
			if atomic.CompareAndSwapInt32(&pFlag, 0, 1) {
				p.handleFunc = cb
				p.usage = opts.Usage
				p.description = opts.Description
				p.middleware = opts.Middleware
				p.params = make([]string, 0, 10)
			}
			if p == nil {
				panic("path can't empty")
			}
			p.params = append(p.params, token[1:])
			continue
		}
		if q, err = p.Children(token); err == nil {
			if i == length-1 {
				panic(path + " already exists")
			}
			p = q
		} else {
			q = NewExecutor(token)
			if i == length-1 {
				q.usage = opts.Usage
				q.description = opts.Description
				q.middleware = opts.Middleware
				q.handleFunc = cb
			}
			p.Append(q)
			p = q
		}
	}
}

func (svr *Server) tcpServe(listener net.Listener) {
	var (
		err  error
		conn net.Conn
	)
	for {
		if conn, err = listener.Accept(); err != nil {
			break
		}
		go func() {
			_ = svr.process(atomic.AddInt32(&svr.seq, 1), conn)
		}()
	}
}

func (svr *Server) unixServe(filename string) (listener net.Listener) {
	var (
		err  error
		addr *net.UnixAddr
	)
	if addr, err = net.ResolveUnixAddr("unix", filename); err != nil {
		return
	}
	if listener, err = net.ListenUnix("unix", addr); err != nil {
		return
	}
	svr.tcpServe(listener)
	return
}

func (svr *Server) Serve(listener net.Listener) (err error) {
	svr.Handle("help", func(ctx *Context) (err error) {
		return ctx.Success(svr.executor.String())
	})
	var (
		wg           sync.WaitGroup
		unixListener net.Listener
	)
	if listener != nil {
		wg.Add(1)
		go func() {
			svr.tcpServe(listener)
			wg.Done()
		}()
	}
	if runtime.GOOS == "linux" {
		go func() {
			//listen unix
			unixListener = svr.unixServe(path.Join(os.TempDir(), os.Getenv("MICRO_SERVICE_NAME")+".sock"))
		}()
	}
	wg.Wait()
	if unixListener != nil {
		err = unixListener.Close()
	}
	return
}

func (svr *Server) Append(child *Executor) {
	svr.executor.Append(child)
}

func New(ctx context.Context) *Server {
	return &Server{
		seq:        0,
		ctx:        ctx,
		executor:   NewExecutor("ROOT"),
		contextMap: make(map[int32]*Context),
	}
}