package hue2

import (
	"bufio"
	"bytes"
	"context"
	"crypto/tls"
	"encoding/json"
	"errors"
	"fmt"
	"git.aiterp.net/lucifer/new-server/internal/lerrors"
	"io"
	"log"
	"net"
	"net/http"
	"strings"
	"time"
)

func NewClient(host, token string) *Client {
	ch := make(chan struct{}, 5)
	for i := 0; i < 2; i++ {
		ch <- struct{}{}
	}

	return &Client{
		host:  host,
		token: token,
		ch:    ch,
	}
}

type Client struct {
	host  string
	token string
	ch    chan struct{}
}

func (c *Client) Register(ctx context.Context) (string, error) {
	result := make([]CreateUserResponse, 0, 1)
	err := c.post(ctx, "api/", CreateUserInput{DeviceType: "git.aiterp.net/lucifer"}, &result)
	if err != nil {
		return "", err
	}

	if len(result) == 0 || result[0].Error != nil {
		select {
		case <-ctx.Done():
			return "", ctx.Err()
		case <-time.After(time.Second):
			return c.Register(ctx)
		}
	}
	if result[0].Success == nil {
		return "", lerrors.ErrUnexpectedResponse
	}

	c.token = result[0].Success.Username

	return result[0].Success.Username, nil
}

func (c *Client) AllResources(ctx context.Context) ([]ResourceData, error) {
	res := struct {
		Error interface{}
		Data  []ResourceData
	}{}

	err := c.get(ctx, "clip/v2/resource", &res)
	if err != nil {
		return nil, err
	}

	return res.Data, nil
}

func (c *Client) Resources(ctx context.Context, kind string) ([]ResourceData, error) {
	res := struct {
		Error interface{}
		Data  []ResourceData
	}{}

	err := c.get(ctx, "clip/v2/resource/"+kind, &res)
	if err != nil {
		return nil, err
	}

	return res.Data, nil
}

func (c *Client) UpdateResource(ctx context.Context, link ResourceLink, update ResourceUpdate) error {
	return c.put(ctx, link.Path(), update, nil)
}

func (c *Client) LegacyDiscover(ctx context.Context, kind string) error {
	return c.legacyPost(ctx, kind, nil, nil)
}

func (c *Client) SSE(ctx context.Context) <-chan SSEUpdate {
	ch := make(chan SSEUpdate, 4)
	go func() {
		defer close(ch)

		reader, err := c.getReader(ctx, "/eventstream/clip/v2", map[string]string{
			"Accept": "text/event-stream",
		})
		if err != nil {
			log.Println("SSE Connect error:", err)
			return
		}

		defer reader.Close()

		br := bufio.NewReader(reader)

		for {
			line, err := br.ReadString('\n')
			if err != nil {
				log.Println("SSE Read error:", err)
				return
			}
			line = strings.Trim(line, "  \t\r\n")
			kv := strings.SplitN(line, ": ", 2)
			if len(kv) < 2 {
				continue
			}

			switch kv[0] {
			case "data":
				var data []SSEUpdate
				err := json.Unmarshal([]byte(kv[1]), &data)
				if err != nil {
					log.Println("Parsing SSE event failed:", err)
					log.Println("  json:", kv[1])
					return
				}

				for _, obj := range data {
					ch <- obj
				}
			}
		}
	}()

	return ch
}

func (c *Client) getReader(ctx context.Context, path string, headers map[string]string) (io.ReadCloser, error) {
	select {
	case <-ctx.Done():
		return nil, ctx.Err()
	case <-c.ch:
		defer func() {
			c.ch <- struct{}{}
		}()
	}

	req, err := http.NewRequest("GET", fmt.Sprintf("https://%s/%s", c.host, path), nil)
	if err != nil {
		return nil, err
	}

	for key, value := range headers {
		req.Header.Set(key, value)
	}
	req.Header.Set("hue-application-key", c.token)

	client := httpClient
	if headers["Accept"] == "text/event-stream" {
		client = sseClient
	}

	res, err := client.Do(req.WithContext(ctx))
	if err != nil {
		return nil, err
	}
	if res.StatusCode != 200 {
		_ = res.Body.Close()
		return nil, errors.New(res.Status)
	}

	return res.Body, nil
}

func (c *Client) get(ctx context.Context, path string, target interface{}) error {
	body, err := c.getReader(ctx, path, map[string]string{})
	if err != nil {
		return err
	}

	defer body.Close()

	if target == nil {
		return nil
	}
	return json.NewDecoder(body).Decode(&target)
}

func (c *Client) put(ctx context.Context, path string, body interface{}, target interface{}) error {
	select {
	case <-ctx.Done():
		return ctx.Err()
	case <-c.ch:
		defer func() {
			c.ch <- struct{}{}
		}()
	}

	rb, err := reqBody(body)
	if err != nil {
		return err
	}

	req, err := http.NewRequest("PUT", fmt.Sprintf("https://%s/%s", c.host, path), rb)
	if err != nil {
		return err
	}

	req.Header.Set("hue-application-key", c.token)

	res, err := httpClient.Do(req.WithContext(ctx))
	if err != nil {
		return err
	}
	defer res.Body.Close()

	if target == nil {
		return nil
	}

	return json.NewDecoder(res.Body).Decode(&target)
}

func (c *Client) post(ctx context.Context, path string, body interface{}, target interface{}) error {
	select {
	case <-ctx.Done():
		return ctx.Err()
	case <-c.ch:
		defer func() {
			c.ch <- struct{}{}
		}()
	}

	rb, err := reqBody(body)
	if err != nil {
		return err
	}

	req, err := http.NewRequest("POST", fmt.Sprintf("https://%s/%s", c.host, path), rb)
	if err != nil {
		return err
	}

	if c.token != "" {
		req.Header.Set("hue-application-key", c.token)
	}

	res, err := httpClient.Do(req.WithContext(ctx))
	if err != nil {
		return err
	}
	defer res.Body.Close()

	if target == nil {
		return nil
	}

	return json.NewDecoder(res.Body).Decode(&target)
}

func (c *Client) legacyPost(ctx context.Context, resource string, body interface{}, target interface{}) error {
	select {
	case <-ctx.Done():
		return ctx.Err()
	case <-c.ch:
		defer func() {
			c.ch <- struct{}{}
		}()
	}

	rb, err := reqBody(body)
	if err != nil {
		return err
	}

	if c.token != "" {
		resource = c.token + "/" + resource
	}

	req, err := http.NewRequest("POST", fmt.Sprintf("http://%s/api/%s", c.host, resource), rb)
	if err != nil {
		return err
	}

	res, err := httpClient.Do(req.WithContext(ctx))
	if err != nil {
		return err
	}
	defer res.Body.Close()

	if target == nil {
		return nil
	}

	return json.NewDecoder(res.Body).Decode(target)
}

func reqBody(body interface{}) (io.Reader, error) {
	if body == nil {
		return nil, nil
	}

	switch v := body.(type) {
	case []byte:
		return bytes.NewReader(v), nil
	case string:
		return strings.NewReader(v), nil
	case io.Reader:
		return v, nil
	default:
		jsonData, err := json.Marshal(v)
		if err != nil {
			return nil, err
		}

		return bytes.NewReader(jsonData), nil
	}
}

var sseClient = &http.Client{
	Transport: &http.Transport{
		Proxy: http.ProxyFromEnvironment,
		DialContext: (&net.Dialer{
			Timeout:   time.Hour * 1000000,
			KeepAlive: 30 * time.Second,
		}).DialContext,
		MaxIdleConns:        5,
		MaxIdleConnsPerHost: 1,
		IdleConnTimeout:     0,
		TLSClientConfig:     &tls.Config{InsecureSkipVerify: true},
	},
	Timeout: time.Hour * 1000000,
}

var httpClient = &http.Client{
	Transport: &http.Transport{
		Proxy: http.ProxyFromEnvironment,
		DialContext: (&net.Dialer{
			Timeout:   30 * time.Second,
			KeepAlive: 30 * time.Second,
		}).DialContext,
		MaxIdleConns:        256,
		MaxIdleConnsPerHost: 16,
		IdleConnTimeout:     10 * time.Minute,
		TLSClientConfig:     &tls.Config{InsecureSkipVerify: true},
	},
	Timeout: time.Minute,
}