package pipeline_api

import (
	"context"
	"fmt"
	"net/http"
	"sync"
	"time"

	apiv2 "git.ohea.xyz/cursorius/pipeline-api/go/api/v2"
	"git.ohea.xyz/cursorius/pipeline-api/go/api/v2/apiv2connect"
	"git.ohea.xyz/cursorius/server/runnermanager"
	"git.ohea.xyz/cursorius/server/util"
	"github.com/bufbuild/connect-go"
	"github.com/google/uuid"
	"github.com/op/go-logging"
)

var log = logging.MustGetLogger("cursorius-server")

type ApiServer struct {
	allocationCh          chan runnermanager.RunnerAllocationRequest
	releaseCh             chan runnermanager.RunnerReleaseRequest
	allocatedRunners      map[uuid.UUID]*RunnerWrapper
	allocatedRunnersMutex sync.RWMutex
}

type RunnerWrapper struct {
	runner *runnermanager.Runner
	mutex  sync.Mutex
}

func (r *RunnerWrapper) RunCommand(cmd string, args []string) (int64, string, string, error) {
	r.mutex.Lock()
	defer r.mutex.Unlock()

	return_code, stdout, stderr, err := r.runner.RunCommand(cmd, args)

	return return_code, stdout, stderr, err
}

func (r *RunnerWrapper) Release(releaseCh chan runnermanager.RunnerReleaseRequest) {
	r.mutex.Lock()
	defer r.mutex.Unlock()

	releaseCh <- runnermanager.RunnerReleaseRequest{
		Runner: r.runner,
	}
	r.runner = nil
}

func (s *ApiServer) GetRunnerFromMap(u uuid.UUID) (*RunnerWrapper, bool) {
	s.allocatedRunnersMutex.RLock()
	defer s.allocatedRunnersMutex.RUnlock()
	runner, ok := s.allocatedRunners[u]
	return runner, ok
}

func (s *ApiServer) AddRunnerToMap(u uuid.UUID, runner *runnermanager.Runner) {
	s.allocatedRunnersMutex.Lock()
	defer s.allocatedRunnersMutex.Unlock()
	s.allocatedRunners[u] = &RunnerWrapper{runner: runner}
}

func (s *ApiServer) GetRunner(
	ctx context.Context,
	req *connect.Request[apiv2.GetRunnerRequest],
) (*connect.Response[apiv2.GetRunnerResponse], error) {

	var response runnermanager.RunnerAllocationResponse
	var timeoutCtx *context.Context
	var retryInterval int64 = 0

	respChan := make(chan runnermanager.RunnerAllocationResponse)

	tagsStr := util.FormatTags(req.Msg.Tags)

	if req.Msg.Options != nil {
		if req.Msg.Options.Timeout != 0 {
			ctx, cancel := context.WithTimeout(context.Background(), time.Duration(req.Msg.Options.Timeout)*time.Second)
			timeoutCtx = &ctx
			defer cancel()
		}

		retryInterval = req.Msg.Options.RetryInterval
	}

	for {
		s.allocationCh <- runnermanager.RunnerAllocationRequest{
			Tags:     req.Msg.Tags,
			RespChan: respChan,
		}

		response = <-respChan
		if response.Err == nil {
			break
		}

		log.Infof("Could not get runner with tags \"%v\": %v", tagsStr, response.Err)

		// If no timeout is specified, skip after one attempt
		if timeoutCtx == nil {
			break
		}

		// If timeout is expired, stop trying to allocate runner
		if (*timeoutCtx).Err() != nil {
			break
		}

		log.Infof("Sleeping for %v seconds before retry...", retryInterval)
		time.Sleep(time.Duration(retryInterval) * time.Second)
	}

	if response.Runner == nil {
		return nil, connect.NewError(connect.CodeNotFound, fmt.Errorf("Could not get runner"))
	}

	log.Infof("Got runner with tags: %v", tagsStr)

	runnerUuid := uuid.New()

	s.AddRunnerToMap(runnerUuid, response.Runner)

	res := connect.NewResponse(&apiv2.GetRunnerResponse{
		Id: runnerUuid.String(),
	})
	res.Header().Set("GetRunner-Version", "v2")
	return res, nil
}

func (s *ApiServer) ReleaseRunner(
	ctx context.Context,
	req *connect.Request[apiv2.ReleaseRunnerRequest],
) (*connect.Response[apiv2.ReleaseRunnerResponse], error) {
	uuid, err := uuid.Parse(req.Msg.Id)
	if err != nil {
		return nil, connect.NewError(connect.CodeInvalidArgument, fmt.Errorf("Invalid runner id"))
	}

	log.Infof("Releasing runner with ID \"%v\"", uuid)

	s.allocatedRunnersMutex.Lock()
	runner := s.allocatedRunners[uuid]
	delete(s.allocatedRunners, uuid)
	runner.Release(s.releaseCh)
	s.allocatedRunnersMutex.Unlock()

	res := connect.NewResponse(&apiv2.ReleaseRunnerResponse{})
	res.Header().Set("ReleaseRunner-Version", "v2")
	return res, nil

}

func (s *ApiServer) RunCommand(
	ctx context.Context,
	req *connect.Request[apiv2.RunCommandRequest],
) (*connect.Response[apiv2.RunCommandResponse], error) {

	uuid, err := uuid.Parse(req.Msg.Id)
	if err != nil {
		return nil, connect.NewError(connect.CodeInvalidArgument, fmt.Errorf("Invalid runner id"))
	}

	runner, ok := s.GetRunnerFromMap(uuid)
	if !ok {
		return nil, connect.NewError(connect.CodeInvalidArgument, fmt.Errorf("Invalid runner id"))
	}

	returnCode, stdout, stderr, err := runner.RunCommand(req.Msg.Command, req.Msg.Args)
	if err != nil {
		log.Errorf("Could not run command on runner \"%v\", %v", runner.runner.Id(), err)
		return nil, connect.NewError(connect.CodeInternal, fmt.Errorf("Could not run command"))
	}

	res := connect.NewResponse(&apiv2.RunCommandResponse{
		ReturnCode: returnCode,
		Stdout:     stdout,
		Stderr:     stderr,
	})
	res.Header().Set("RunCommand-Version", "v2")
	return res, nil
}

func CreateHandler(allocationCh chan runnermanager.RunnerAllocationRequest, releaseCh chan runnermanager.RunnerReleaseRequest, mux *http.ServeMux) {
	api_server := &ApiServer{
		allocationCh:     allocationCh,
		releaseCh:        releaseCh,
		allocatedRunners: make(map[uuid.UUID]*RunnerWrapper),
	}
	path, handler := apiv2connect.NewGetRunnerServiceHandler(api_server)
	mux.Handle(path, handler)
	path, handler = apiv2connect.NewReleaseRunnerServiceHandler(api_server)
	mux.Handle(path, handler)
	path, handler = apiv2connect.NewRunCommandServiceHandler(api_server)
	mux.Handle(path, handler)
}