package hvpnnode3

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"log/slog"
	"net/http"

	"github.com/felixge/httpsnoop"
	"github.com/google/uuid"

	"gitea.hbanafa.com/HeshamTB/hvpn-node3/proto"
)

type CtxKey string
const CtxReqID CtxKey = "request_id"

func HandleGetNodeInfo(wgLink *WGLink) http.HandlerFunc {
    return func(w http.ResponseWriter, r *http.Request) {
        reqID := r.Context().Value(CtxReqID).(uuid.UUID)
        debug("Preparing node info for", reqID)
        dev, err := wgLink.Device(wgLink.Name)
        if err != nil {
            w.WriteHeader(http.StatusInternalServerError)
            return
        }

        json.NewEncoder(w).Encode(
            proto.NodePublicInfo{
                PublicKey: dev.PublicKey.String(),
                UDPPort: dev.ListenPort,
                Endpoint: wgLink.Endpoint,
                // TODO: Send endpoint for clients to connect
            },
        )
    }
}

func HandleGetPeer(wgLink *WGLink) http.HandlerFunc {
    return func(w http.ResponseWriter, r *http.Request) {
        reqID :=  r.Context().Value(CtxReqID).(uuid.UUID)
        pubkey := r.PathValue("pubkey")
        debug(pubkey, reqID)
        peer, err := wgLink.GetPeer(pubkey)
        if err != nil {
            if errors.Is(err, proto.PeerDoesNotExist){
                json.NewEncoder(w).Encode(
                    proto.ErrJSONResponse{Message: "Peer does not exist"},
                )
                w.WriteHeader(http.StatusNotFound)
                return
            }
            w.WriteHeader(http.StatusInternalServerError)
            return
        }
        err = json.NewEncoder(w).Encode(proto.WgPeerToPeer(*peer))
        if err != nil {
            slog.Error(err.Error())
        }

    }
}

func HandleGetPeers(wgLink *WGLink) http.HandlerFunc {
    return func(w http.ResponseWriter, r *http.Request) {
        reqID :=  r.Context().Value(CtxReqID).(uuid.UUID)
        debug("GET Peers for", reqID)
        dev, err := wgLink.Device(wgLink.Name)
        if err != nil {
            w.WriteHeader(http.StatusInternalServerError)
            slog.Error(err.Error())
            return
        }
        var peers []proto.Peer
        for _, peer := range dev.Peers {
            p := proto.WgPeerToPeer(peer)
            peers = append(peers, p)
        }
        err = json.NewEncoder(w).Encode(peers)
        if err != nil {
            w.WriteHeader(http.StatusInternalServerError)
        }
        return
    }
}

func HandlePostPeer(wgLink *WGLink) http.HandlerFunc {
    return func(w http.ResponseWriter, r* http.Request) {
        reqID := r.Context().Value(CtxReqID).(uuid.UUID)
        debug("POST Peer for", reqID)
        peerRequest := proto.CreatePeerRequest{}
        err := json.NewDecoder(r.Body).Decode(&peerRequest)
        if err != nil {
           w.WriteHeader(http.StatusBadRequest) 
           json.NewEncoder(w).Encode(
               &proto.ErrJSONResponse{Message: "Invalid request JSON"},
           )
           return
        }

        if valid := ValidKey(peerRequest.PublicKey); !valid {
            w.WriteHeader(http.StatusBadRequest)
            json.NewEncoder(w).Encode(
                proto.ErrJSONResponse{Message: "Invalid public key"},
            )
            return
        }

        exists, err := wgLink.Exists(peerRequest.PublicKey)
        if err != nil {
            w.WriteHeader(http.StatusInternalServerError)
            json.NewEncoder(w).Encode(
                proto.ErrJSONResponse{Message: "Error while checking peer existance"},
            )
            return
        }
        if exists {
            debugf("Peer %s already exists", reqID, peerRequest.PublicKey)
            w.WriteHeader(http.StatusFound)
            peer, err := wgLink.GetPeer(peerRequest.PublicKey)
            if err != nil {
                slog.Error(err.Error())
                return
            }
            json.NewEncoder(w).Encode(
                proto.WgPeerToPeer(*peer),
            )
            return
        }

        peer, err := wgLink.AddPeer(peerRequest.PublicKey)
        if err != nil {
            slog.Error(err.Error())
            w.WriteHeader(http.StatusInternalServerError)
            json.NewEncoder(w).Encode(
                proto.ErrJSONResponse{Message: "Error while adding peer"},
            )
            return
        }
        debugf("Allocated IP: %s", reqID, peer.AllowedIPs[0].IP.String())
        w.WriteHeader(http.StatusCreated)
        json.NewEncoder(w).Encode(
            proto.WgPeerToPeer(*peer),
        )
    }
}

func HandleDeletePeer(wg *WGLink) http.HandlerFunc {
    return func(w http.ResponseWriter, r *http.Request) {
        reqId := r.Context().Value(CtxReqID).(uuid.UUID)
        pubkey := r.PathValue("pubkey")
        debugf("DELETE Peer %s", reqId, pubkey)
        exists, err := wg.Exists(pubkey)
        if err != nil {
            w.WriteHeader(http.StatusInternalServerError)
            slog.Error(err.Error())
            return
        }
        if !exists {
            w.WriteHeader(http.StatusNotFound)
            json.NewEncoder(w).Encode(
                proto.ErrJSONResponse{Message: "Peer does not exist"},
            )
            return
        }
        err = wg.DeletePeer(pubkey)
        if err != nil {
            w.WriteHeader(http.StatusInternalServerError)
            json.NewEncoder(w).Encode(
                proto.ErrJSONResponse{Message: "Error while deleting peer"},
            )
            slog.Error(err.Error())
        }
    }
}

func HttpLogHandler2(h http.Handler) http.Handler {
    // https://blog.kowalczyk.info/article/e00e89c3841e4f8c8c769a78b8a90b47/logging-http-requests-in-go.html
    fn := func(w http.ResponseWriter, r* http.Request) {
        reqID, _ := uuid.NewRandom() 
        rCtx := context.WithValue(r.Context(), CtxReqID, reqID)
        r = r.WithContext(rCtx)
        slog.Info(fmt.Sprintf("Starting request with ID: %s", reqID.String()))
        m := httpsnoop.CaptureMetrics(h, w, r)
        msg := fmt.Sprintf(
            "[HTTP] %s %s %s %d %s %s", r.RemoteAddr, r.Method,
            r.URL.String(),m.Code, m.Duration, reqID.String()) 
        slog.Info(msg)
    }
    return http.HandlerFunc(fn)
}

func debugf(format string, reqID uuid.UUID,  args ...any) {
    format = format + " " + reqID.String() 
    slog.Debug(fmt.Sprintf(format, args...))
}

func debug(msg string, reqID uuid.UUID) {
    msg = msg + " " + reqID.String()
    debugf("%s", reqID, msg)
}