package execution

import (
	"context"
	"encoding/json"
	"fmt"
	"oc-scheduler/conf"
	"oc-scheduler/infrastructure/planner"
	"oc-scheduler/infrastructure/scheduling_resources"
	infUtils "oc-scheduler/infrastructure/utils"
	"strings"
	"sync"
	"time"

	oclib "cloud.o-forge.io/core/oc-lib"
	"cloud.o-forge.io/core/oc-lib/dbs"
	"cloud.o-forge.io/core/oc-lib/models/booking"
	"cloud.o-forge.io/core/oc-lib/models/common/enum"
	"cloud.o-forge.io/core/oc-lib/models/order"
	"cloud.o-forge.io/core/oc-lib/models/utils"
	"cloud.o-forge.io/core/oc-lib/models/workflow"
	"cloud.o-forge.io/core/oc-lib/models/workflow_execution"
	"cloud.o-forge.io/core/oc-lib/tools"
	"go.mongodb.org/mongo-driver/bson/primitive"
)

// ---------------------------------------------------------------------------
// Global execution lock registry
// ---------------------------------------------------------------------------

var execLocksMu sync.RWMutex
var execLocks = map[string]*sync.Mutex{}

func RegisterExecLock(executionID string) {
	execLocksMu.Lock()
	execLocks[executionID] = &sync.Mutex{}
	execLocksMu.Unlock()
}

func UnregisterExecLock(executionID string) {
	execLocksMu.Lock()
	delete(execLocks, executionID)
	execLocksMu.Unlock()
}

func GetExecLock(executionID string) *sync.Mutex {
	execLocksMu.RLock()
	mu := execLocks[executionID]
	execLocksMu.RUnlock()
	return mu
}

// ---------------------------------------------------------------------------
// Considers payload
// ---------------------------------------------------------------------------

type ConsidersPayload struct {
	ID           string   `json:"id"`
	ExecutionsID string   `json:"executions_id"`
	ExecutionID  string   `json:"execution_id"`
	PeerIDs      []string `json:"peer_ids"`
}

// ---------------------------------------------------------------------------
// Execution state machine — considers
// ---------------------------------------------------------------------------

func UpdateExecutionState(payload []byte, dt tools.DataType) {
	var data ConsidersPayload
	if err := json.Unmarshal(payload, &data); err != nil || data.ID == "" {
		return
	}
	schdata := oclib.NewRequestAdmin(oclib.LibDataEnum(dt), nil).LoadOne(data.ID)
	if schdata.Data == nil {
		return
	}
	sch := scheduling_resources.ToSchedulerObject(dt, schdata.Data)
	if sch == nil {
		return
	}
	execID := sch.GetExecutionId()

	mu := GetExecLock(execID)
	if mu == nil {
		fmt.Printf("UpdateExecutionState: no lock for execution %s, skipping\n", execID)
		return
	}
	mu.Lock()
	defer mu.Unlock()

	adminReq := &tools.APIRequest{Admin: true}
	res, _, err := workflow_execution.NewAccessor(adminReq).LoadOne(execID)
	if err != nil || res == nil {
		fmt.Printf("UpdateExecutionState: could not load execution %s: %v\n", execID, err)
		return
	}
	exec := res.(*workflow_execution.WorkflowExecution)

	switch dt {
	case tools.BOOKING:
		if exec.BookingsState == nil {
			exec.BookingsState = map[string]bool{}
		}
		exec.BookingsState[data.ID] = true
	case tools.PURCHASE_RESOURCE:
		if exec.PurchasesState == nil {
			exec.PurchasesState = map[string]bool{}
		}
		exec.PurchasesState[data.ID] = true
	}

	allConfirmed := true
	for _, st := range exec.BookingsState {
		if !st {
			allConfirmed = false
			break
		}
	}
	if allConfirmed {
		for _, st := range exec.PurchasesState {
			if !st {
				allConfirmed = false
				break
			}
		}
	}
	if allConfirmed {
		exec.State = enum.SCHEDULED
		exec.IsDraft = false
	}
	if _, _, err := utils.GenericRawUpdateOne(exec, exec.GetID(), workflow_execution.NewAccessor(adminReq)); err != nil {
		fmt.Printf("UpdateExecutionState: could not update execution %s: %v\n", execID, err)
		return
	}
	if allConfirmed {
		go confirmSessionOrder(exec.ExecutionsID, adminReq)
		obj, _, err := workflow.NewAccessor(adminReq).LoadOne(exec.WorkflowID)
		if err == nil && obj != nil {
			go EmitConsidersExecution(exec, obj.(*workflow.Workflow))
		}
	}
}

func confirmSessionOrder(executionsID string, adminReq *tools.APIRequest) {
	results, _, _ := order.NewAccessor(adminReq).Search(
		&dbs.Filters{And: map[string][]dbs.Filter{
			"executions_id": {{Operator: dbs.EQUAL.String(), Value: executionsID}},
		}}, "", true)
	for _, obj := range results {
		if o, ok := obj.(*order.Order); ok {
			o.IsDraft = false
			utils.GenericRawUpdateOne(o, o.GetID(), order.NewAccessor(adminReq))
		}
	}
}

func ConfirmExecutionDrafts(payload []byte) {
	var data ConsidersPayload
	if err := json.Unmarshal(payload, &data); err != nil {
		fmt.Printf("ConfirmExecutionDrafts: could not parse payload: %v\n", err)
		return
	}
	d := oclib.NewRequestAdmin(oclib.LibDataEnum(tools.WORKFLOW_EXECUTION), nil).LoadOne(data.ExecutionID)
	if exec := d.ToWorkflowExecution(); exec != nil {
		for id := range exec.BookingsState {
			go scheduling_resources.Confirm(id, tools.BOOKING)
		}
		for id := range exec.PurchasesState {
			go scheduling_resources.Confirm(id, tools.PURCHASE_RESOURCE)
		}
	}
}

func EmitConsidersExecution(exec *workflow_execution.WorkflowExecution, wf *workflow.Workflow) {
	if wf == nil || wf.Graph == nil {
		return
	}
	peerIDs, err := infUtils.GetWorkflowPeerIDs(wf.GetID(), &tools.APIRequest{Admin: true})
	if err != nil || len(peerIDs) == 0 {
		return
	}
	payload, err := json.Marshal(ConsidersPayload{
		ID:           exec.GetID(),
		ExecutionID:  exec.GetID(),
		ExecutionsID: exec.ExecutionsID,
		PeerIDs:      peerIDs,
	})
	if err != nil {
		return
	}
	b, err := json.Marshal(tools.PropalgationMessage{
		DataType: int(tools.WORKFLOW_EXECUTION),
		Action:   tools.PB_CONSIDERS,
		Payload:  payload,
	})
	if err != nil {
		return
	}
	tools.NewNATSCaller().SetNATSPub(tools.PROPALGATION_EVENT, tools.NATSResponse{
		FromApp:  "oc-scheduler",
		Datatype: tools.WORKFLOW_EXECUTION,
		Method:   int(tools.PROPALGATION_EVENT),
		Payload:  b,
	})
}

// ---------------------------------------------------------------------------
// Deadline watchers
// ---------------------------------------------------------------------------

func WatchDeadline(executionID string, ns string, execDate time.Time, request *tools.APIRequest) {
	delay := time.Until(execDate.UTC().Add(-1 * time.Minute))
	if delay <= 0 {
		go handleDeadline(executionID, ns, request)
		return
	}
	time.AfterFunc(delay, func() { handleDeadline(executionID, ns, request) })
}

func handleDeadline(executionID string, ns string, request *tools.APIRequest) {
	res, _, err := workflow_execution.NewAccessor(&tools.APIRequest{Admin: true}).LoadOne(executionID)
	if err != nil || res == nil {
		fmt.Printf("handleDeadline: execution %s not found\n", executionID)
		return
	}
	adminReq := &tools.APIRequest{Admin: true}
	exec := res.(*workflow_execution.WorkflowExecution)
	if exec.IsDraft {
		Unschedule(executionID, request)
		workflow_execution.NewAccessor(adminReq).DeleteOne(executionID)
		fmt.Printf("handleDeadline: purged draft execution %s\n", executionID)
		return
	}
	if serv, err := tools.NewKubernetesService(
		conf.GetConfig().KubeHost+":"+conf.GetConfig().KubePort,
		conf.GetConfig().KubeCA, conf.GetConfig().KubeCert, conf.GetConfig().KubeData); err != nil {
		fmt.Printf("handleDeadline: k8s init failed for %s: %v\n", executionID, err)
	} else if err := serv.ProvisionExecutionNamespace(context.Background(), ns); err != nil &&
		!strings.Contains(err.Error(), "already exists") {
		fmt.Printf("handleDeadline: failed to provision namespace %s: %v\n", ns, err)
	}
	go watchEnd(executionID, ns, exec.EndDate, exec.ExecDate)
}

func watchEnd(executionID string, ns string, endDate *time.Time, execDate time.Time) {
	var end time.Time
	if endDate != nil {
		end = *endDate
	} else {
		end = execDate.UTC().Add(5 * time.Minute)
	}
	fire := func() {
		serv, err := tools.NewKubernetesService(
			conf.GetConfig().KubeHost+":"+conf.GetConfig().KubePort,
			conf.GetConfig().KubeCA, conf.GetConfig().KubeCert, conf.GetConfig().KubeData)
		if err != nil {
			fmt.Printf("watchEnd: k8s init failed for %s: %v\n", executionID, err)
			return
		}
		if err := serv.TeardownExecutionNamespace(context.Background(), ns); err != nil {
			fmt.Printf("watchEnd: failed to teardown namespace %s: %v\n", ns, err)
		}
	}
	if delay := time.Until(end.UTC()); delay <= 0 {
		go fire()
	} else {
		time.AfterFunc(delay, fire)
	}
}

// ---------------------------------------------------------------------------
// Unschedule / Recovery
// ---------------------------------------------------------------------------

func Unschedule(executionID string, request *tools.APIRequest) error {
	adminReq := &tools.APIRequest{Admin: true}
	res, _, err := workflow_execution.NewAccessor(adminReq).LoadOne(executionID)
	if err != nil || res == nil {
		return fmt.Errorf("execution %s not found: %w", executionID, err)
	}
	exec := res.(*workflow_execution.WorkflowExecution)
	for _, byResource := range exec.PeerBookByGraph {
		for _, bookingIDs := range byResource {
			for _, bkID := range bookingIDs {
				bkRes, _, loadErr := booking.NewAccessor(adminReq).LoadOne(bkID)
				if loadErr != nil || bkRes == nil {
					continue
				}
				scheduling_resources.GetService().Delete(
					tools.BOOKING,
					scheduling_resources.ToSchedulerObject(tools.BOOKING, bkRes),
					request,
				)
			}
		}
	}
	workflow_execution.NewAccessor(adminReq).DeleteOne(executionID)
	UnregisterExecLock(executionID)
	return nil
}

func RecoverDraft() {
	adminReq := &tools.APIRequest{Admin: true}
	results, _, _ := workflow_execution.NewAccessor(adminReq).Search(nil, "*", true)
	for _, obj := range results {
		exec, ok := obj.(*workflow_execution.WorkflowExecution)
		if !ok {
			continue
		}
		RegisterExecLock(exec.GetID())
		go WatchDeadline(exec.GetID(), exec.ExecutionsID, exec.ExecDate, adminReq)
	}
	fmt.Printf("RecoverDraft: recovered %d executions\n", len(results))
}

// ---------------------------------------------------------------------------
// NATS workflow lifecycle handlers
// ---------------------------------------------------------------------------

func HandleWorkflowStarted(resp tools.NATSResponse) {
	var evt tools.WorkflowLifecycleEvent
	if err := json.Unmarshal(resp.Payload, &evt); err != nil {
		return
	}
	adminReq := &tools.APIRequest{Admin: true}
	res, _, err := workflow_execution.NewAccessor(adminReq).LoadOne(evt.ExecutionID)
	if err != nil || res == nil {
		return
	}
	exec := res.(*workflow_execution.WorkflowExecution)
	exec.State = enum.STARTED
	if evt.RealStart != nil {
		exec.ExecDate = *evt.RealStart
	}
	utils.GenericRawUpdateOne(exec, exec.GetID(), workflow_execution.NewAccessor(adminReq))
}

func HandleWorkflowDone(resp tools.NATSResponse) {
	var evt tools.WorkflowLifecycleEvent
	if err := json.Unmarshal(resp.Payload, &evt); err != nil {
		return
	}
	adminReq := &tools.APIRequest{Admin: true}
	res, _, err := workflow_execution.NewAccessor(adminReq).LoadOne(evt.ExecutionID)
	if err != nil || res == nil {
		return
	}
	exec := res.(*workflow_execution.WorkflowExecution)
	exec.State = enum.BookingStatus(evt.State)
	if evt.RealEnd != nil {
		exec.EndDate = evt.RealEnd
	}
	utils.GenericRawUpdateOne(exec, exec.GetID(), workflow_execution.NewAccessor(adminReq))
	for _, step := range evt.Steps {
		applyStepToBooking(step, adminReq)
	}
	self, err := oclib.GetMySelf()
	if err == nil && self != nil {
		go planner.GetPlannerService().RefreshSelf(self.PeerID, adminReq)
	}
}

func HandleWorkflowStepDone(resp tools.NATSResponse) {
	var evt tools.WorkflowLifecycleEvent
	if err := json.Unmarshal(resp.Payload, &evt); err != nil || evt.BookingID == "" {
		return
	}
	adminReq := &tools.APIRequest{Admin: true}
	res, _, err := booking.NewAccessor(adminReq).LoadOne(evt.BookingID)
	if err != nil || res == nil {
		return
	}
	bk := res.(*booking.Booking)
	bk.State = enum.BookingStatus(evt.State)
	if evt.RealStart != nil {
		bk.RealStartDate = evt.RealStart
	}
	if evt.RealEnd != nil {
		bk.RealEndDate = evt.RealEnd
	}
	utils.GenericRawUpdateOne(bk, bk.GetID(), booking.NewAccessor(adminReq))
	switch bk.State {
	case enum.SUCCESS, enum.FAILURE, enum.FORGOTTEN, enum.CANCELLED:
		self, err := oclib.GetMySelf()
		if err == nil && self != nil {
			go planner.GetPlannerService().RefreshSelf(self.PeerID, adminReq)
		}
	}
}

func applyStepToBooking(step tools.StepMetric, adminReq *tools.APIRequest) {
	res, _, err := booking.NewAccessor(adminReq).LoadOne(step.BookingID)
	if err != nil || res == nil {
		return
	}
	bk := res.(*booking.Booking)
	switch bk.State {
	case enum.SUCCESS, enum.FAILURE, enum.FORGOTTEN, enum.CANCELLED:
		return
	}
	bk.State = enum.BookingStatus(step.State)
	if step.RealStart != nil {
		bk.RealStartDate = step.RealStart
	}
	if step.RealEnd != nil {
		bk.RealEndDate = step.RealEnd
	}
	utils.GenericRawUpdateOne(bk, bk.GetID(), booking.NewAccessor(adminReq))
}

// ---------------------------------------------------------------------------
// Watchdog — stale execution safety net
// ---------------------------------------------------------------------------

var processedExecutions sync.Map

var terminalExecStates = map[enum.BookingStatus]bool{
	enum.SUCCESS: true, enum.FAILURE: true, enum.FORGOTTEN: true, enum.CANCELLED: true,
}

func WatchExecutions() {
	logger := oclib.GetLogger()
	logger.Info().Msg("ExecutionWatchdog: started")
	ticker := time.NewTicker(time.Minute)
	defer ticker.Stop()
	for range ticker.C {
		if err := scanStaleExecutions(); err != nil {
			logger.Error().Msg("ExecutionWatchdog: " + err.Error())
		}
	}
}

func scanStaleExecutions() error {
	myself, err := oclib.GetMySelf()
	if err != nil {
		return fmt.Errorf("could not resolve local peer: %w", err)
	}
	deadline := time.Now().UTC().Add(-time.Minute)
	res := oclib.NewRequest(oclib.LibDataEnum(oclib.WORKFLOW_EXECUTION), "", myself.GetID(), []string{}, nil).
		Search(&dbs.Filters{And: map[string][]dbs.Filter{
			"execution_date": {{Operator: dbs.LTE.String(), Value: primitive.NewDateTimeFromTime(deadline)}},
		}}, "", false)
	if res.Err != "" {
		return fmt.Errorf("stale execution search failed: %s", res.Err)
	}
	for _, dbo := range res.Data {
		if exec, ok := dbo.(*workflow_execution.WorkflowExecution); ok {
			go emitExecutionFailure(exec)
		}
	}
	return nil
}

func emitExecutionFailure(exec *workflow_execution.WorkflowExecution) {
	logger := oclib.GetLogger()
	if _, done := processedExecutions.Load(exec.GetID()); done {
		return
	}
	if terminalExecStates[exec.State] {
		processedExecutions.Store(exec.GetID(), struct{}{})
		return
	}
	now := time.Now().UTC()
	steps := make([]tools.StepMetric, 0)
	for _, byGraph := range exec.PeerBookByGraph {
		for _, bookingIDs := range byGraph {
			for _, bookingID := range bookingIDs {
				payload, err := json.Marshal(tools.WorkflowLifecycleEvent{
					ExecutionID:  exec.GetID(),
					ExecutionsID: exec.ExecutionsID,
					BookingID:    bookingID,
					State:        enum.FAILURE.EnumIndex(),
					RealEnd:      &now,
				})
				if err != nil {
					continue
				}
				tools.NewNATSCaller().SetNATSPub(tools.WORKFLOW_STEP_DONE_EVENT, tools.NATSResponse{
					FromApp: "oc-scheduler-watchdog",
					Method:  int(tools.WORKFLOW_STEP_DONE_EVENT),
					Payload: payload,
				})
				steps = append(steps, tools.StepMetric{
					BookingID: bookingID,
					State:     enum.FAILURE.EnumIndex(),
					RealEnd:   &now,
				})
			}
		}
	}
	donePayload, err := json.Marshal(tools.WorkflowLifecycleEvent{
		ExecutionID:  exec.GetID(),
		ExecutionsID: exec.ExecutionsID,
		State:        enum.FAILURE.EnumIndex(),
		RealEnd:      &now,
		Steps:        steps,
	})
	if err == nil {
		tools.NewNATSCaller().SetNATSPub(tools.WORKFLOW_DONE_EVENT, tools.NATSResponse{
			FromApp: "oc-scheduler-watchdog",
			Method:  int(tools.WORKFLOW_DONE_EVENT),
			Payload: donePayload,
		})
	}
	logger.Info().Msgf("ExecutionWatchdog: execution %s stale → emitting FAILURE (%d bookings)",
		exec.GetID(), len(steps))
	processedExecutions.Store(exec.GetID(), struct{}{})
}