package steamcache

import (
	"io"
	"log"
	"net/http"
	"net/url"
	"s1d3sw1ped/SteamCache2/vfs"
	"s1d3sw1ped/SteamCache2/vfs/cache"
	"s1d3sw1ped/SteamCache2/vfs/disk"
	"s1d3sw1ped/SteamCache2/vfs/gc"
	"s1d3sw1ped/SteamCache2/vfs/memory"
	syncfs "s1d3sw1ped/SteamCache2/vfs/sync"
	"strings"
	"sync"
	"time"

	"github.com/docker/go-units"
)

type SteamCache struct {
	address string
	vfs     vfs.VFS

	memory *memory.MemoryFS
	disk   *disk.DiskFS

	dirty bool
	mu    sync.Mutex
}

func New(address string, memorySize string, memoryMultiplier int, diskSize string, diskMultiplier int, diskPath string) *SteamCache {
	memorysize, err := units.FromHumanSize(memorySize)
	if err != nil {
		panic(err)
	}

	disksize, err := units.FromHumanSize(diskSize)
	if err != nil {
		panic(err)
	}

	m := memory.New(memorysize)
	d := disk.New(diskPath, disksize)

	sc := &SteamCache{
		address: address,
		vfs: syncfs.New(
			cache.New(
				gc.New(
					m,
					memoryMultiplier,
					memorygc,
				),
				gc.New(
					d,
					diskMultiplier,
					diskgc,
				),
				cachehandler,
			),
		),

		memory: m,
		disk:   d,
	}

	if d.Size() > d.Capacity() {
		diskgc(d, int(d.Size()-d.Capacity()))
	}

	return sc
}

func (sc *SteamCache) Run() {
	log.Printf("SteamCache2 running on %s", sc.address)

	sc.mu.Lock()
	sc.dirty = true
	sc.mu.Unlock()

	sc.LogStats()

	t := time.NewTicker(10 * time.Second)
	go func() {
		for range t.C {
			// log cache stats
			sc.LogStats()
		}
	}()

	http.ListenAndServe(sc.address, sc)
}

func (sc *SteamCache) LogStats() {
	sc.mu.Lock()
	defer sc.mu.Unlock()
	if sc.dirty {
		log.Printf(
			"SteamCache2 %s: (%d) %s/%s   %s: (%d) %s/%s",
			sc.memory.Name(), len(sc.memory.StatAll()), units.HumanSize(float64(sc.memory.Size())), units.HumanSize(float64(sc.memory.Capacity())),
			sc.disk.Name(), len(sc.disk.StatAll()), units.HumanSize(float64(sc.disk.Size())), units.HumanSize(float64(sc.disk.Capacity())),
		)
		sc.dirty = false
	}
}

func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {

	if r.Method != http.MethodGet {
		http.Error(w, "Only GET method is supported", http.StatusMethodNotAllowed)
		return
	}

	if r.URL.String() == "/lancache-heartbeat" {
		w.Header().Add("X-LanCache-Processed-By", "SteamCache2")
		w.WriteHeader(http.StatusNoContent)
		w.Write(nil)
		return
	}

	if r.Header.Get("User-Agent") != "Valve/Steam HTTP Client 1.0" {
		http.Error(w, "Only Valve/Steam HTTP Client 1.0 is supported", http.StatusForbidden)
		return
	}

	if strings.Contains(r.URL.String(), "manifest") {
		w.Header().Add("X-LanCache-Processed-By", "SteamCache2")
		forward(w, r)
		return
	}

	tstart := time.Now()
	defer func() {
		log.Printf("%s %s %s took %s", r.Method, r.URL.String(), w.Header().Get("X-LanCache-Status"), time.Since(tstart))
	}()

	sc.mu.Lock()
	sc.dirty = true
	sc.mu.Unlock()

	w.Header().Add("X-LanCache-Processed-By", "SteamCache2") // SteamPrefill uses this header to determine if the request was processed by the cache maybe steam uses it too

	cacheKey := r.URL.String()

	// if vfs is also a vfs.GetSer, we can use it to get the cache state

	data, err := sc.vfs.Get(cacheKey)
	if err == nil {
		w.Header().Add("X-LanCache-Status", "HIT")
		w.Write(data)
		return
	}

	htt := "http://"
	if r.Header.Get("X-Sls-Https") == "enable" {
		htt = "https://"
	}

	base := htt + r.Host

	hosturl, err := url.JoinPath(base, cacheKey)
	if err != nil {
		http.Error(w, "Failed to join URL path", http.StatusInternalServerError)
		return
	}

	resp, err := http.Get(hosturl)
	if err != nil {
		http.Error(w, "Failed to fetch the requested URL", http.StatusInternalServerError)
		return
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		http.Error(w, "Failed to fetch the requested URL", resp.StatusCode)
		return
	}

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		http.Error(w, "Failed to read response body", http.StatusInternalServerError)
		return
	}

	sc.vfs.Set(cacheKey, body)
	w.Header().Add("X-LanCache-Status", "MISS")
	w.Write(body)
}

func forward(w http.ResponseWriter, r *http.Request) {
	htt := "http://"
	if r.Header.Get("X-Sls-Https") == "enable" {
		htt = "https://"
	}

	base := htt + r.Host

	cacheKey := r.URL.String()

	hosturl, err := url.JoinPath(base, cacheKey)
	if err != nil {
		http.Error(w, "Failed to join URL path", http.StatusInternalServerError)
		return
	}

	resp, err := http.Get(hosturl)
	if err != nil {
		http.Error(w, "Failed to fetch the requested URL", http.StatusInternalServerError)
		return
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		http.Error(w, "Failed to fetch the requested URL", resp.StatusCode)
		return
	}

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		http.Error(w, "Failed to read response body", http.StatusInternalServerError)
		return
	}

	w.Header().Add("X-LanCache-Status", "MISS")
	w.Write(body)
}