package main

import (
	"crypto/sha256"
	"crypto/tls"
	"encoding/base64"
	"encoding/json"
	"flag"
	encode_utils "git.gammaspectra.live/S.O.N.G/Ignite/cli/encode-utils"
	"gopkg.in/yaml.v3"
	"io"
	"net/http"
	"net/url"
	"os"
	"slices"
	"strconv"
	"sync"
	"sync/atomic"
	"time"
)

var DefaultClient = &http.Client{
	Timeout: time.Second * 5,
}

var InsecureDefaultClient = &http.Client{
	Timeout: time.Second * 5,
	Transport: &http.Transport{
		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
	},
}

type ServerConfig struct {
	URL         string `yaml:"url"`
	Key         string `yaml:"key"`
	InsecureSSL bool   `yaml:"insecure_ssl"`
	lastStatus  atomic.Pointer[encode_utils.StatusData]
	nextStatus  atomic.Int64
}

func (s *ServerConfig) Status() *encode_utils.StatusData {
	if time.Unix(s.nextStatus.Load(), 0).Compare(time.Now()) < 0 {
		defer func() {
			s.nextStatus.Store(time.Now().Add(time.Second * 30).Unix())
		}()
		u, _ := url.Parse(s.URL + "/status?k=" + s.Key)
		response, err := s.Do(&http.Request{
			Method: "GET",
			URL:    u,
		})
		if err != nil {
			return s.lastStatus.Load()
		}
		defer response.Body.Close()
		dataBuf, err := io.ReadAll(response.Body)
		if err != nil {
			return s.lastStatus.Load()
		}
		var status encode_utils.StatusData
		err = json.Unmarshal(dataBuf, &status)
		if err != nil {
			return s.lastStatus.Load()
		}
		s.lastStatus.Store(&status)
	}
	return s.lastStatus.Load()
}

func (s *ServerConfig) Do(r *http.Request) (*http.Response, error) {
	if s.InsecureSSL {
		return InsecureDefaultClient.Do(r)
	} else {
		return DefaultClient.Do(r)
	}
}

func (s *ServerConfig) Pass(r *http.Request, replaceValues ...[2]string) (*http.Response, error) {
	urlPath := r.URL

	newUrl := s.URL + urlPath.String()
	urlPath, _ = url.Parse(newUrl)
	q := urlPath.Query()

	for _, v := range replaceValues {
		q.Set(v[0], v[1])
	}
	urlPath.RawQuery = q.Encode()

	return s.Do(&http.Request{
		Method: r.Method,
		URL:    urlPath,
		Header: r.Header,
		Body:   r.Body,
	})
}

func (s *ServerConfig) Redirect(w http.ResponseWriter, r *http.Request, replaceValues ...[2]string) {
	urlPath := r.URL

	newUrl := s.URL + urlPath.String()
	urlPath, _ = url.Parse(newUrl)
	q := urlPath.Query()

	for _, v := range replaceValues {
		q.Set(v[0], v[1])
	}
	urlPath.RawQuery = q.Encode()

	http.Redirect(w, r, urlPath.String(), http.StatusTemporaryRedirect)
}

type PoolConfig struct {
	Servers []*ServerConfig `yaml:"servers"`
}

var poolConfig PoolConfig

var jobMutex sync.Mutex

type Job struct {
	Id       string                 `json:"id"`
	Config   encode_utils.JobConfig `json:"config"`
	ServerId string                 `json:"server_id"`
	Server   *ServerConfig          `json:"server"`
}

var jobs []*Job

func main() {
	configPath := flag.String("config", "pool.yml", "Configuration path for server pool")
	listenAddr := flag.String("listen", "0.0.0.0:8484", "Listen address for the server")

	flag.Parse()

	fData, err := os.ReadFile(*configPath)
	if err != nil {
		panic(err)
	}

	err = yaml.Unmarshal(fData, &poolConfig)
	if err != nil {
		panic(err)
	}

	serveMux := http.NewServeMux()

	serveMux.HandleFunc("/create", func(w http.ResponseWriter, r *http.Request) {
		for {
			for _, s := range poolConfig.Servers {
				if job := func(s *ServerConfig) *Job {
					response, err := s.Pass(r, [2]string{"k", s.Key})
					if err != nil {
						return nil
					}
					defer response.Body.Close()
					defer io.ReadAll(response.Body)
					if response.StatusCode == http.StatusOK {
						var job struct {
							Id     string                 `json:"id"`
							Config encode_utils.JobConfig `json:"config"`
						}
						dataBuf, err := io.ReadAll(response.Body)
						if err != nil {
							return nil
						}
						err = json.Unmarshal(dataBuf, &job)
						if err != nil {
							return nil
						}
						jobId := sha256.Sum256(append([]byte(job.Id), s.URL...))
						return &Job{
							Id:       base64.RawURLEncoding.EncodeToString(jobId[:]),
							Config:   job.Config,
							ServerId: job.Id,
							Server:   s,
						}
					}
					return nil
				}(s); job != nil {
					jobMutex.Lock()
					defer jobMutex.Unlock()
					jobs = append(jobs, job)
					data, err := json.Marshal(job)
					if err != nil {
						w.WriteHeader(http.StatusBadRequest)
						_, _ = w.Write([]byte(err.Error()))
						return
					}
					w.Header().Set("Content-Type", "application/json")
					w.Header().Set("Content-Length", strconv.FormatUint(uint64(len(data)), 10))
					w.WriteHeader(http.StatusOK)
					_, _ = w.Write(data)
					return
				}
			}
			// Check every few seconds for any space for new jobs
			// TODO: do this globally aware + pool via channels
			time.Sleep(time.Second * 30)
		}
	})

	serveMux.HandleFunc("/start", func(w http.ResponseWriter, r *http.Request) {
		query := r.URL.Query()

		jobId := query.Get("jobId")

		jobMutex.Lock()
		defer jobMutex.Unlock()
		if i := slices.IndexFunc(jobs, func(job *Job) bool {
			return job.Id == jobId
		}); i == -1 {
			w.WriteHeader(http.StatusNotFound)
			return
		} else {
			job := jobs[i]
			job.Server.Redirect(w, r, [2]string{"k", job.Server.Key}, [2]string{"jobId", job.ServerId})
		}
	})

	serveMux.HandleFunc("/startURL", func(w http.ResponseWriter, r *http.Request) {
		query := r.URL.Query()

		jobId := query.Get("jobId")

		jobMutex.Lock()
		defer jobMutex.Unlock()
		if i := slices.IndexFunc(jobs, func(job *Job) bool {
			return job.Id == jobId
		}); i == -1 {
			w.WriteHeader(http.StatusNotFound)
			return
		} else {
			job := jobs[i]
			job.Server.Redirect(w, r, [2]string{"k", job.Server.Key}, [2]string{"jobId", job.ServerId})
		}
	})

	serveMux.HandleFunc("/job", func(w http.ResponseWriter, r *http.Request) {
		query := r.URL.Query()

		jobId := query.Get("jobId")

		jobMutex.Lock()
		defer jobMutex.Unlock()
		if i := slices.IndexFunc(jobs, func(job *Job) bool {
			return job.Id == jobId
		}); i == -1 {
			w.WriteHeader(http.StatusNotFound)
			return
		} else {
			job := jobs[i]
			job.Server.Redirect(w, r, [2]string{"k", job.Server.Key}, [2]string{"jobId", job.ServerId})
		}
	})

	serveMux.HandleFunc("/remove", func(w http.ResponseWriter, r *http.Request) {
		query := r.URL.Query()

		jobId := query.Get("jobId")

		jobMutex.Lock()
		defer jobMutex.Unlock()
		if i := slices.IndexFunc(jobs, func(job *Job) bool {
			return job.Id == jobId
		}); i == -1 {
			w.WriteHeader(http.StatusNotFound)
			return
		} else {
			jobs = slices.Delete(jobs, i, i+1)
			job := jobs[i]
			job.Server.Redirect(w, r, [2]string{"k", job.Server.Key}, [2]string{"jobId", job.ServerId})
		}
	})

	s := http.Server{
		ReadTimeout:  time.Second * 10,
		IdleTimeout:  time.Second * 60,
		WriteTimeout: 0,
		Addr:         *listenAddr,
		Handler:      serveMux,
	}
	s.SetKeepAlivesEnabled(true)

	if err := s.ListenAndServe(); err != nil {
		panic(err)
	}
	defer s.Close()
}