package api

import (
	"encoding/json"
	"net/http"
	"strconv"

	"github.com/go-chi/chi/v5"
	"github.com/go-chi/chi/v5/middleware"
	k8sclient "github.com/vandachevici/games-console/internal/k8s"
	"github.com/vandachevici/games-console/internal/health"
)

const nodeHost = "192.168.2.100"

// NewRouter returns a chi router with all API routes registered.
func NewRouter(client *k8sclient.Client) http.Handler {
	r := chi.NewRouter()
	r.Use(middleware.Logger)
	r.Use(middleware.Recoverer)
	r.Use(corsMiddleware)

	r.Get("/healthz", handleHealthz)

	r.Route("/api/servers", func(r chi.Router) {
		r.Get("/", makeListServers(client))
		r.Post("/", makeCreateServer(client))
		r.Get("/{name}", makeGetServer(client))
		r.Put("/{name}", makeUpdateServer(client))
		r.Delete("/{name}", makeDeleteServer(client))
		r.Get("/{name}/logs", makeGetLogs(client))
		r.Get("/{name}/health", makeHealthCheck(client))
		r.Post("/{name}/start", makeStart(client))
		r.Post("/{name}/stop", makeStop(client))
		r.Post("/{name}/restart", makeRestart(client))
	})

	return r
}

func corsMiddleware(next http.Handler) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		w.Header().Set("Access-Control-Allow-Origin", "*")
		w.Header().Set("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS")
		w.Header().Set("Access-Control-Allow-Headers", "Content-Type")
		if r.Method == http.MethodOptions {
			w.WriteHeader(http.StatusNoContent)
			return
		}
		next.ServeHTTP(w, r)
	})
}

func handleHealthz(w http.ResponseWriter, r *http.Request) {
	writeJSON(w, http.StatusOK, map[string]string{"status": "ok"})
}

func makeListServers(c *k8sclient.Client) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		servers, err := c.ListServers(r.Context())
		if err != nil {
			writeError(w, http.StatusInternalServerError, err)
			return
		}
		writeJSON(w, http.StatusOK, servers)
	}
}

func makeGetServer(c *k8sclient.Client) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		name := chi.URLParam(r, "name")
		server, err := c.GetServer(r.Context(), name)
		if err != nil {
			writeError(w, http.StatusNotFound, err)
			return
		}
		writeJSON(w, http.StatusOK, server)
	}
}

func makeCreateServer(c *k8sclient.Client) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		var req k8sclient.CreateServerRequest
		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
			writeError(w, http.StatusBadRequest, err)
			return
		}
		server, err := c.CreateServer(r.Context(), req)
		if err != nil {
			writeError(w, http.StatusInternalServerError, err)
			return
		}
		writeJSON(w, http.StatusCreated, server)
	}
}

func makeUpdateServer(c *k8sclient.Client) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		name := chi.URLParam(r, "name")
		var req k8sclient.UpdateServerRequest
		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
			writeError(w, http.StatusBadRequest, err)
			return
		}
		server, err := c.UpdateServer(r.Context(), name, req)
		if err != nil {
			writeError(w, http.StatusInternalServerError, err)
			return
		}
		writeJSON(w, http.StatusOK, server)
	}
}

func makeDeleteServer(c *k8sclient.Client) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		name := chi.URLParam(r, "name")
		if err := c.DeleteServer(r.Context(), name); err != nil {
			writeError(w, http.StatusInternalServerError, err)
			return
		}
		w.WriteHeader(http.StatusNoContent)
	}
}

func makeGetLogs(c *k8sclient.Client) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		name := chi.URLParam(r, "name")
		lines := int64(100)
		if l := r.URL.Query().Get("lines"); l != "" {
			if n, err := strconv.ParseInt(l, 10, 64); err == nil {
				lines = n
			}
		}
		logs, err := c.GetLogs(r.Context(), name, lines)
		if err != nil {
			writeError(w, http.StatusInternalServerError, err)
			return
		}
		writeJSON(w, http.StatusOK, map[string]string{"logs": logs})
	}
}

func makeHealthCheck(c *k8sclient.Client) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		name := chi.URLParam(r, "name")
		server, err := c.GetServer(r.Context(), name)
		if err != nil {
			writeError(w, http.StatusNotFound, err)
			return
		}
		tcpReachable := false
		if server.NodePort > 0 {
			tcpReachable = health.Probe(nodeHost, server.NodePort)
		}
		writeJSON(w, http.StatusOK, map[string]interface{}{
			"status":       server.Status,
			"tcpReachable": tcpReachable,
			"nodePort":     server.NodePort,
		})
	}
}

func makeStart(c *k8sclient.Client) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		name := chi.URLParam(r, "name")
		if err := c.ScaleServer(r.Context(), name, 1); err != nil {
			writeError(w, http.StatusInternalServerError, err)
			return
		}
		writeJSON(w, http.StatusOK, map[string]string{"status": "started"})
	}
}

func makeStop(c *k8sclient.Client) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		name := chi.URLParam(r, "name")
		if err := c.ScaleServer(r.Context(), name, 0); err != nil {
			writeError(w, http.StatusInternalServerError, err)
			return
		}
		writeJSON(w, http.StatusOK, map[string]string{"status": "stopped"})
	}
}

func makeRestart(c *k8sclient.Client) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		name := chi.URLParam(r, "name")
		if err := c.RestartServer(r.Context(), name); err != nil {
			writeError(w, http.StatusInternalServerError, err)
			return
		}
		writeJSON(w, http.StatusOK, map[string]string{"status": "restarting"})
	}
}

func writeJSON(w http.ResponseWriter, status int, v interface{}) {
	w.Header().Set("Content-Type", "application/json")
	w.WriteHeader(status)
	json.NewEncoder(w).Encode(v)
}

func writeError(w http.ResponseWriter, status int, err error) {
	writeJSON(w, status, map[string]string{"error": err.Error()})
}