package main

/*
   #include <stdlib.h>
   #include <stdint.h>
   #include <errno.h>
   
   #include "client.h"
   #include "netio.h"
   #include "controller.capnp.h"
   #include "helper.h"

   typedef struct {
       xcecli_ctx_t ctx;
       uintptr_t    go_handler;
       void*        go_apiserver;
   } apiserver_ctx_t;
   
   extern int go_callback(uintptr_t, xce_request_t*, apiserver_ctx_t *);
   
   static int xce_apiserver_handler(xce_request_t *req, void *arg) {
      int rc = -EINVAL;
      apiserver_ctx_t *ctx = (apiserver_ctx_t *)arg;

      if (ctx == NULL) {
          return -EINVAL;
      }
      
      if (ctx->go_handler != 0) {
         rc = go_callback(ctx->go_handler, req, arg);
      }
      
      return rc;
   }
   
   static int xce_apiserver_init(xce_client_config_t *config, apiserver_ctx_t *ctx) {
      int rc;

      if ((config == NULL) || (ctx == NULL)) {
          return -EINVAL;
      }
      
      rc = xcecli_ctx_init(&(ctx->ctx), config);
      if (rc < 0) {
         return rc;
      }

      xcecli_set_handler(ctx->ctx, (xce_request_handler_t)xce_apiserver_handler, ctx);

      rc = xcecli_start(ctx->ctx);
      if (rc < 0) {
         return rc;
      }

      rc = xcecli_join(ctx->ctx, HostRole_apiserver, NULL);

      return rc;
   }

   static xce_job_t **dataset_jobs(dataset_t *d) {
      return (xce_job_t **)d->rows;
   }

   static xce_worker_t **dataset_workers(dataset_t *d) {
      return (xce_worker_t **)d->rows;
   }
*/
import "C"

import (
	"fmt"
	"unsafe"
	"runtime/cgo"
	"log"
	"net/http"
)

type ApiServer struct {
	// add data here
}

//export go_callback
func go_callback(h C.uintptr_t, req *C.xce_request_t, ctx *C.apiserver_ctx_t) C.int {
	fn := cgo.Handle(h).Value().(func(*C.xce_request_t,*C.apiserver_ctx_t) C.int)
	return fn(req, ctx);
}

func (apiserver *ApiServer) handle_config(config *C.xce_configdata_t) C.int {
	switch (config.data_which) {
	case C.ConfigData_data_clusterconfig:
		fmt.Printf("cluster configuration received\n")
		// Extract configuration information from config
		// - queues
		// - resources information
		// - and other information
	default:
		//
		fmt.Printf("unhandled config request %d\n", config.data_which)
	}
	return 0
}

func print_job(job *C.xce_job_t) {
	fmt.Printf("jobid `%v' user `%s' queue `%s'\n",uint64(job.jobid), C.GoString(job.submit.user), C.GoString(job.submit.queue))
}

func print_worker(w *C.xce_worker_t) {
	fmt.Printf("worker `%s'\n", C.GoString(w.name))
}

func (apiserver *ApiServer) handle_job_push(jobs []*C.xce_job_t) C.int {
	// add all jobs to apiserver
	for i := range jobs {
		print_job(jobs[i])
	}
	
	return 0
}

func (apiserver *ApiServer) handle_worker_push(workers []*C.xce_worker_t) C.int {
	// add all workers to api server
	for i := range workers {
		print_worker(workers[i])
	}
 	return 0
}

func (apiserver *ApiServer)handle_dataset(dataset *C.dataset_t) C.int {
	
	fmt.Printf("handle dataset table %d\n", dataset.table)
	switch(dataset.table) {
	case C.Data_data_schedjobs:
		fmt.Printf("%d jobs arrived\n", dataset.nrows)
		var theJobs **C.xce_job_t = C.dataset_jobs(dataset) 

		jobs := unsafe.Slice(theJobs, dataset.nrows)
		
		return apiserver.handle_job_push(jobs)
	case C.Data_data_schedworkers:
		fmt.Printf("%d workers arrived\n", dataset.nrows)
		var theWorkers **C.xce_worker_t = C.dataset_workers(dataset)

		workers := unsafe.Slice(theWorkers, dataset.nrows)
		return apiserver.handle_worker_push(workers)
	default:
		//
	}
	return 0
}
func go_req_handler(request *C.xce_request_t, ctx *C.apiserver_ctx_t) C.int {
	var from = C.GoString(request.from.name)
	var body_which = request.body_which
	var apiserver  = (*ApiServer)(unsafe.Pointer(ctx.go_apiserver))
	
	fmt.Println("api server handler called")
	fmt.Printf("op `%s' body_which %d from %s\n", C.GoString(C.xce_request_op_name(request)), body_which, from)

	switch (request.opcode) {
	case C.OPCode_push:
		switch (body_which) {
		case C.Request_body_configpushmsg:
			// handle push config
			return apiserver.handle_config((*C.xce_configdata_t)(unsafe.Pointer(C.xce_request_body(request))))
		case C.Request_body_datamsg:
			// handle pushed data msg
			return apiserver.handle_dataset((*C.dataset_t)(unsafe.Pointer(C.xce_request_body(request))))
		default:
			// something wrong
		}
	default:
	}
	
	C.free_Request(request)
	
	return 0
}

func init_config(config *C.xce_client_config_t) C.int {
	config.nmasters =1
	config.masters[0] = C.CString("localhost")
	config.master_ports[0] = C.int(9990);
	config.from = C.CString("xce_apiserver")
	config.key = C.CString("keepsecret$")
	
	return 0
}

func (apiserver *ApiServer) handle_job_query(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "URL.Path = %q\n", r.URL.Path)
}

func main() {
	var config C.xce_client_config_t
	var ctx C.apiserver_ctx_t
	var apiserver ApiServer

	init_config(&config)
	
	h := cgo.NewHandle(go_req_handler)
	defer h.Delete()
	
	ctx.go_handler = C.uintptr_t(h)
	ctx.go_apiserver = unsafe.Pointer(&apiserver)
	
	rc := C.xce_apiserver_init(&config, &ctx)
	fmt.Printf("rc %d\n", rc);

	http.HandleFunc("/jobs", (&apiserver).handle_job_query)
	
	log.Fatal(http.ListenAndServe("localhost:8000", nil))
}