package infrastructure

import (
	"encoding/json"
	"errors"
	"fmt"
	"oc-scheduler/infrastructure/scheduling"
	"strings"
	"time"

	oclib "cloud.o-forge.io/core/oc-lib"
	"cloud.o-forge.io/core/oc-lib/models/bill"
	"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/common/pricing"
	"cloud.o-forge.io/core/oc-lib/models/order"
	"cloud.o-forge.io/core/oc-lib/models/peer"
	"cloud.o-forge.io/core/oc-lib/models/resources/purchase_resource"
	"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"
	"github.com/google/uuid"
	"github.com/robfig/cron"
)

/*
* WorkflowSchedule is a struct that contains the scheduling information of a workflow
* It contains the mode of the schedule (Task or Service), the name of the schedule, the start and end time of the schedule and the cron expression
 */
// it's a flying object only use in a session time. It's not stored in the database
type WorkflowSchedule struct {
	UUID              string                                  `json:"id" validate:"required"`                // ExecutionsID is the list of the executions id of the workflow
	Workflow          *workflow.Workflow                      `json:"workflow,omitempty"`                    // Workflow is the workflow dependancy of the schedule
	WorkflowExecution []*workflow_execution.WorkflowExecution `json:"workflow_executions,omitempty"`         // WorkflowExecution is the list of executions of the workflow
	Message           string                                  `json:"message,omitempty"`                     // Message is the message of the schedule
	Warning           string                                  `json:"warning,omitempty"`                     // Warning is the warning message of the schedule
	Start             time.Time                               `json:"start" validate:"required,ltfield=End"` // Start is the start time of the schedule, is required and must be less than the End time
	End               *time.Time                              `json:"end,omitempty"`                         // End is the end time of the schedule, is required and must be greater than the Start time
	DurationS         float64                                 `json:"duration_s" default:"-1"`               // End is the end time of the schedule
	Cron              string                                  `json:"cron,omitempty"`                        // here the cron format : ss mm hh dd MM dw task

	BookingMode          booking.BookingMode `json:"booking_mode,omitempty"` // BookingMode qualify the preemption order of the scheduling. if no payment allowed with preemption set up When_Possible
	SelectedInstances    workflow.ConfigItem `json:"selected_instances"`
	SelectedPartnerships workflow.ConfigItem `json:"selected_partnerships"`
	SelectedBuyings      workflow.ConfigItem `json:"selected_buyings"`
	SelectedStrategies   workflow.ConfigItem `json:"selected_strategies"`

	SelectedBillingStrategy pricing.BillingStrategy `json:"selected_billing_strategy"`

	// Confirm, when true, triggers Schedule() to confirm the drafts held by this session.
	Confirm bool `json:"confirm,omitempty"`
}

func NewScheduler(mode int, start string, end string, durationInS float64, cron string) *WorkflowSchedule {
	ws := &WorkflowSchedule{
		UUID:        uuid.New().String(),
		Start:       time.Now().UTC().Add(asapBuffer),
		BookingMode: booking.BookingMode(mode),
		DurationS:   durationInS,
		Cron:        cron,
	}
	s, err := time.ParseInLocation("2006-01-02T15:04:05", start, time.UTC)
	if err == nil && ws.BookingMode == booking.PLANNED {
		ws.Start = s // can apply a defined start other than now, if planned
	}

	e, err := time.ParseInLocation("2006-01-02T15:04:05", end, time.UTC)
	if err == nil {
		ws.End = &e
	}
	return ws
}

func (ws *WorkflowSchedule) GetBuyAndBook(wfID string, request *tools.APIRequest) (bool, *workflow.Workflow, []*workflow_execution.WorkflowExecution, []scheduling.SchedulerObject, []scheduling.SchedulerObject, error) {
	access := workflow.NewAccessor(request)
	res, code, err := access.LoadOne(wfID)
	if code != 200 {
		return false, nil, []*workflow_execution.WorkflowExecution{}, []scheduling.SchedulerObject{}, []scheduling.SchedulerObject{}, errors.New("could not load the workflow with id: " + err.Error())
	}
	wf := res.(*workflow.Workflow)
	isPreemptible, longest, priceds, wf, err := wf.Planify(ws.Start, ws.End,
		ws.SelectedInstances, ws.SelectedPartnerships, ws.SelectedBuyings, ws.SelectedStrategies,
		int(ws.BookingMode), request)
	if err != nil {
		return false, wf, []*workflow_execution.WorkflowExecution{}, []scheduling.SchedulerObject{}, []scheduling.SchedulerObject{}, err
	}
	ws.DurationS = longest
	ws.Message = "We estimate that the workflow will start at " + ws.Start.String() + " and last " + fmt.Sprintf("%v", ws.DurationS) + " seconds."
	if ws.End != nil && ws.Start.Add(time.Duration(longest)*time.Second).After(*ws.End) {
		ws.Warning = "The workflow may be too long to be executed in the given time frame, we will try to book it anyway\n"
	}
	execs, err := ws.GetExecutions(wf, isPreemptible)
	if err != nil {
		return false, wf, []*workflow_execution.WorkflowExecution{}, []scheduling.SchedulerObject{}, []scheduling.SchedulerObject{}, err
	}
	purchased := []scheduling.SchedulerObject{}
	bookings := []scheduling.SchedulerObject{}
	for _, exec := range execs {
		for _, obj := range exec.Buy(ws.SelectedBillingStrategy, ws.UUID, wfID, priceds) {
			purchased = append(purchased, scheduling.ToSchedulerObject(tools.PURCHASE_RESOURCE, obj))
		}
		for _, obj := range exec.Book(ws.UUID, wfID, priceds) {
			bookings = append(bookings, scheduling.ToSchedulerObject(tools.BOOKING, obj))
		}
	}
	return true, wf, execs, purchased, bookings, nil
}

// GenerateOrder creates a draft order (+ draft bill) for the given purchases and bookings.
// Returns the created order ID and any error.
func (ws *WorkflowSchedule) GenerateOrder(purchases []scheduling.SchedulerObject, bookings []scheduling.SchedulerObject, executionsID string, request *tools.APIRequest) (string, error) {
	newOrder := &order.Order{
		AbstractObject: utils.AbstractObject{
			Name:    "order_" + request.PeerID + "_" + time.Now().UTC().Format("2006-01-02T15:04:05"),
			IsDraft: true,
		},
		ExecutionsID: executionsID,
		Purchases:    []*purchase_resource.PurchaseResource{},
		Bookings:     []*booking.Booking{},
		Status:       enum.PENDING,
	}
	for _, purch := range purchases {
		newOrder.Purchases = append(
			newOrder.Purchases, scheduling.FromSchedulerObject(tools.PURCHASE_RESOURCE, purch).(*purchase_resource.PurchaseResource))
	}
	for _, b := range bookings {
		newOrder.Bookings = append(
			newOrder.Bookings, scheduling.FromSchedulerObject(tools.BOOKING, b).(*booking.Booking))
	}
	res, _, err := order.NewAccessor(request).StoreOne(newOrder)
	if err != nil {
		return "", err
	}
	if _, err := bill.DraftFirstBill(res.(*order.Order), request); err != nil {
		return res.GetID(), err
	}
	return res.GetID(), nil
}

func (ws *WorkflowSchedule) Schedules(wfID string, request *tools.APIRequest) (*WorkflowSchedule, *workflow.Workflow, []*workflow_execution.WorkflowExecution, error) {
	if request == nil {
		return ws, nil, []*workflow_execution.WorkflowExecution{}, errors.New("no request found")
	}
	selfID, _ := oclib.GetMySelf()

	// If the client provides a scheduling_id from a Check session, confirm the
	// pre-created drafts (bookings/purchases). Executions already exist as drafts
	// and will be confirmed later by the considers mechanism.
	if ws.UUID != "" {
		adminReq := &tools.APIRequest{Admin: true}

		// Obsolescence check: abort if any session execution's start date has passed.
		executions := loadSessionExecs(ws.UUID)
		for _, exec := range executions {
			if !exec.ExecDate.IsZero() && exec.ExecDate.Before(time.Now().UTC()) {
				return ws, nil, nil, fmt.Errorf("execution %s is obsolete (start date in the past)", exec.GetID())
			}
		}

		if err := ConfirmSession(ws.UUID, selfID, request); err != nil {
			return ws, nil, []*workflow_execution.WorkflowExecution{}, fmt.Errorf("confirm session failed: %w", err)
		}

		for _, exec := range executions {
			go WatchExecDeadline(exec.GetID(), exec.ExecutionsID, exec.ExecDate, selfID, request)
		}

		obj, _, _ := workflow.NewAccessor(request).LoadOne(wfID)
		if obj == nil {
			return ws, nil, executions, nil
		}
		wf := obj.(*workflow.Workflow)
		ws.Workflow = wf
		ws.WorkflowExecution = executions
		wf.GetAccessor(adminReq).UpdateOne(wf.Serialize(wf), wf.GetID())
		return ws, wf, executions, nil
	}

	// Schedule must be called from a Check session (ws.UUID set above).
	// Direct scheduling without a prior Check session is not supported.
	return ws, nil, []*workflow_execution.WorkflowExecution{}, errors.New("no scheduling session: use the Check stream first")
}

// propagateResource routes a purchase or booking to its destination:
//   - If destPeerID matches our own peer (selfMongoID), the object is stored
//     directly in the local DB as draft and the local planner is refreshed.
//   - Otherwise a NATS CREATE_RESOURCE message is emitted so the destination
//     peer can process it asynchronously.
//
// The caller is responsible for setting obj.IsDraft before calling.
func propagateResource(obj utils.DBObject, destPeerID string, dt tools.DataType, selfMongoID *peer.Peer, request *tools.APIRequest, errCh chan error) {
	if destPeerID == selfMongoID.GetID() {
		stored := oclib.NewRequestAdmin(oclib.LibDataEnum(dt), nil).StoreOne(obj.Serialize(obj))
		if stored.Err != "" || stored.Data == nil {
			errCh <- fmt.Errorf("could not store %s locally: %s", dt.String(), stored.Err)
			return
		}
		// The planner tracks booking time-slots only; purchases do not affect it.
		if dt == tools.BOOKING {
			go refreshSelfPlanner(selfMongoID.PeerID, request)
		}
		errCh <- nil
		return
	}
	m := obj.Serialize(obj)
	if m["dest_peer_id"] != nil {
		if data := oclib.NewRequestAdmin(oclib.LibDataEnum(oclib.PEER), nil).LoadOne(fmt.Sprintf("%v", m["dest_peer_id"])); data.Data != nil {
			m["peer_id"] = data.Data.(*peer.Peer).PeerID
		}
	} else {
		fmt.Println("NO DEST ID")
		return
	}
	payload, err := json.Marshal(m)
	if err != nil {
		errCh <- fmt.Errorf("could not serialize %s: %w", dt.String(), err)
		return
	}
	if b, err := json.Marshal(&tools.PropalgationMessage{
		DataType: dt.EnumIndex(),
		Action:   tools.PB_CREATE,
		Payload:  payload,
	}); err == nil {
		tools.NewNATSCaller().SetNATSPub(tools.PROPALGATION_EVENT, tools.NATSResponse{
			FromApp:  "oc-scheduler",
			Datatype: dt,
			Method:   int(tools.PROPALGATION_EVENT),
			Payload:  b,
		})
	}
	errCh <- nil
}

/*
* getExecutions is a function that returns the executions of a workflow
* it returns an array of workflow_execution.WorkflowExecution
 */
func (ws *WorkflowSchedule) GetExecutions(workflow *workflow.Workflow, isPreemptible bool) ([]*workflow_execution.WorkflowExecution, error) {
	workflows_executions := []*workflow_execution.WorkflowExecution{}
	dates, err := ws.GetDates()
	if err != nil {
		return workflows_executions, err
	}
	for _, date := range dates {
		obj := &workflow_execution.WorkflowExecution{
			AbstractObject: utils.AbstractObject{
				UUID: uuid.New().String(),                                 // set the uuid of the execution
				Name: workflow.Name + "_execution_" + date.Start.String(), // set the name of the execution
			},
			Priority:     1,
			ExecutionsID: ws.UUID,
			ExecDate:     date.Start,       // set the execution date
			EndDate:      date.End,         // set the end date
			State:        enum.DRAFT,       // set the state to 1 (scheduled)
			WorkflowID:   workflow.GetID(), // set the workflow id dependancy of the execution
		}
		if ws.BookingMode != booking.PLANNED {
			obj.Priority = 0
		}
		if ws.BookingMode == booking.PREEMPTED && isPreemptible {
			obj.Priority = 7
		}

		ws.SelectedStrategies = obj.SelectedStrategies
		ws.SelectedPartnerships = obj.SelectedPartnerships
		ws.SelectedBuyings = obj.SelectedBuyings
		ws.SelectedInstances = obj.SelectedInstances

		workflows_executions = append(workflows_executions, obj)
	}
	return workflows_executions, nil
}

func (ws *WorkflowSchedule) GetDates() ([]Schedule, error) {
	schedule := []Schedule{}
	if len(ws.Cron) > 0 { // if cron is set then end date should be set
		if ws.End == nil {
			return schedule, errors.New("a cron task should have an end date")
		}
		if ws.DurationS <= 0 {
			ws.DurationS = ws.End.Sub(ws.Start).Seconds()
		}
		cronStr := strings.Split(ws.Cron, " ") // split the cron string to treat it
		if len(cronStr) < 6 {                  // if the cron string is less than 6 fields, return an error because format is : ss mm hh dd MM dw (6 fields)
			return schedule, errors.New("Bad cron message: (" + ws.Cron + "). Should be at least ss mm hh dd MM dw")
		}
		subCron := strings.Join(cronStr[:6], " ")
		// cron should be parsed as ss mm hh dd MM dw t (min 6 fields)
		specParser := cron.NewParser(cron.Second | cron.Minute | cron.Hour | cron.Dom | cron.Month | cron.Dow) // create a new cron parser
		sched, err := specParser.Parse(subCron)                                                                // parse the cron string
		if err != nil {
			return schedule, errors.New("Bad cron message: " + err.Error())
		}
		// loop through the cron schedule to set the executions
		for s := sched.Next(ws.Start); !s.IsZero() && s.Before(*ws.End); s = sched.Next(s) {
			e := s.Add(time.Duration(ws.DurationS) * time.Second)
			schedule = append(schedule, Schedule{
				Start: s,
				End:   &e,
			})
		}
	} else { // if no cron, set the execution to the start date
		schedule = append(schedule, Schedule{
			Start: ws.Start,
			End:   ws.End,
		})
	}
	return schedule, nil
}

type Schedule struct {
	Start time.Time
	End   *time.Time
}

/*
* TODO : LARGEST GRAIN PLANIFYING THE WORKFLOW WHEN OPTION IS SET
* SET PROTECTION BORDER TIME
 */