package client

import (
	"fmt"
	"sync/atomic"
	"time"

	"github.com/theater/picomap/lib/halfsiphash"
	"github.com/theater/picomap/lib/msgpack"
)

var HashKey = [8]byte{}

type transport interface {
	Send(data []byte) error
	SetReadTimeout(timeout time.Duration)
	Recv() (data []byte, from string, err error)
	Broadcast() bool
	Close() error
}

type Client struct {
	transport transport
	timeout   time.Duration
	nextID    atomic.Uint32
}

func (c *Client) Close() error {
	return c.transport.Close()
}

func (c *Client) send(msg any) (uint32, error) {
	id := c.nextID.Add(1)
	payload, err := msgpack.Marshal(msg)
	if err != nil {
		return 0, fmt.Errorf("encode inner: %w", err)
	}
	checksum := halfsiphash.Sum32(payload, HashKey)
	env := Envelope{MessageID: id, Checksum: checksum, Payload: payload}
	data, err := msgpack.Marshal(&env)
	if err != nil {
		return 0, fmt.Errorf("encode envelope: %w", err)
	}
	return id, c.transport.Send(data)
}

type Response[T any] struct {
	From  string
	Value *T
}

func roundTrip[T any](c *Client, req any) ([]Response[T], error) {
	id, err := c.send(req)
	if err != nil {
		return nil, err
	}
	c.transport.SetReadTimeout(c.timeout)
	broadcast := c.transport.Broadcast()
	var results []Response[T]
	for {
		data, from, err := c.transport.Recv()
		if err != nil {
			break
		}
		var env Envelope
		if err := msgpack.Unmarshal(data, &env); err != nil {
			continue
		}
		if env.MessageID != id {
			continue
		}
		expected := halfsiphash.Sum32(env.Payload, HashKey)
		if env.Checksum != expected {
			continue
		}
		var inner any
		if err := msgpack.Unmarshal(env.Payload, &inner); err != nil {
			continue
		}
		if devErr, ok := inner.(*DeviceError); ok {
			return nil, devErr
		}
		if typed, ok := inner.(*T); ok {
			results = append(results, Response[T]{From: from, Value: typed})
			if !broadcast {
				break
			}
		}
	}
	return results, nil
}

func first[T any](results []Response[T], err error) (*T, error) {
	if err != nil {
		return nil, err
	}
	if len(results) == 0 {
		return nil, fmt.Errorf("no response")
	}
	return results[0].Value, nil
}

func (c *Client) PICOBOOT() error {
	_, err := first(roundTrip[ResponsePICOBOOT](c, &RequestPICOBOOT{}))
	return err
}

func (c *Client) Info() (*ResponseInfo, error) {
	return first(roundTrip[ResponseInfo](c, &RequestInfo{}))
}

func (c *Client) InfoAll() ([]Response[ResponseInfo], error) {
	return roundTrip[ResponseInfo](c, &RequestInfo{})
}

func (c *Client) Log() (*ResponseLog, error) {
	return first(roundTrip[ResponseLog](c, &RequestLog{}))
}

func (c *Client) Test(name string) (*ResponseTest, error) {
	return first(roundTrip[ResponseTest](c, &RequestTest{Name: name}))
}