package api

import (
	"net/http"
	"net/http/httptest"
	"strings"
	"sync"
	"testing"

	"github.com/gin-gonic/gin"
)

func countLifecycleWinners(instanceID string, workers int) int {
	start := make(chan struct{})
	results := make(chan bool, workers)
	var wg sync.WaitGroup
	for range workers {
		wg.Add(1)
		go func() {
			defer wg.Done()
			<-start
			results <- beginInstanceLifecycleOperation(instanceID)
		}()
	}
	close(start)
	wg.Wait()
	close(results)
	winners := 0
	for won := range results {
		if won {
			winners++
		}
	}
	return winners
}

func TestBeginInstanceLifecycleOperationSingleFlight(t *testing.T) {
	instanceID := "ocid1.instance.oc1..single-flight"
	instanceLifecycleGuard.Delete(instanceID)
	t.Cleanup(func() { instanceLifecycleGuard.Delete(instanceID) })
	if got, want := countLifecycleWinners(instanceID, 16), 1; got != want {
		t.Errorf("winners = %d, want %d", got, want)
	}
}

func instanceOperationRouter() *gin.Engine {
	h := &ociConfigHandler{}
	r := gin.New()
	r.DELETE("/oci-configs/:id/instances/:instanceId", h.terminateInstance)
	r.POST("/oci-configs/:id/instances/:instanceId/action", h.instanceAction)
	return r
}

func TestInstanceLifecycleOperationRejectsLaterRequest(t *testing.T) {
	gin.SetMode(gin.TestMode)
	instanceID := "ocid1.instance.oc1..same-physical-instance"
	instanceLifecycleGuard.Store(instanceID, struct{}{})
	t.Cleanup(func() { instanceLifecycleGuard.Delete(instanceID) })
	r := instanceOperationRouter()
	tests := []struct {
		name, method, path, body string
	}{
		{"action先占位时跨配置terminate被拒", http.MethodDelete, "/oci-configs/2/instances/" + instanceID, ""},
		{"terminate先占位时action被拒", http.MethodPost, "/oci-configs/1/instances/" + instanceID + "/action", `{"action":"STOP"}`},
		{"action先占位时第二个action被拒", http.MethodPost, "/oci-configs/3/instances/" + instanceID + "/action", `{"action":"RESET"}`},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			req := httptest.NewRequest(tt.method, tt.path, strings.NewReader(tt.body))
			req.Header.Set("Content-Type", "application/json")
			w := httptest.NewRecorder()
			r.ServeHTTP(w, req)
			if got, want := w.Code, http.StatusConflict; got != want {
				t.Errorf("status = %d, want %d, body %s", got, want, w.Body.String())
			}
		})
	}
}