package outbox

import (
	"context"
	"time"

	"github.com/tech/sendico/pkg/db/repository"
	ri "github.com/tech/sendico/pkg/db/repository/index"
	"github.com/tech/sendico/pkg/merrors"
	"github.com/tech/sendico/pkg/mlogger"
	"go.mongodb.org/mongo-driver/v2/bson"
	"go.mongodb.org/mongo-driver/v2/mongo"
	"go.uber.org/zap"
)

type mongoStore struct {
	logger mlogger.Logger
	repo   repository.Repository
}

func NewMongoStore(logger mlogger.Logger, db *mongo.Database) (Store, error) {
	if db == nil {
		return nil, merrors.InvalidArgument("mongo database is nil")
	}
	if logger == nil {
		logger = zap.NewNop()
	}
	repo := repository.CreateMongoRepository(db, Collection)

	statusIndex := &ri.Definition{
		Keys: []ri.Key{{Field: "status", Sort: ri.Asc}, {Field: "createdAt", Sort: ri.Asc}},
	}
	if err := repo.CreateIndex(statusIndex); err != nil {
		logger.Error("Failed to ensure outbox status index", zap.Error(err))
		return nil, err
	}

	eventIDIndex := &ri.Definition{
		Keys:   []ri.Key{{Field: "eventId", Sort: ri.Asc}},
		Unique: true,
	}
	if err := repo.CreateIndex(eventIDIndex); err != nil {
		logger.Error("Failed to ensure outbox eventId index", zap.Error(err))
		return nil, err
	}

	childLogger := logger.Named(Collection)
	childLogger.Debug("Outbox store initialised", zap.String("collection", Collection))

	return &mongoStore{logger: childLogger, repo: repo}, nil
}

func (o *mongoStore) Create(ctx context.Context, event *Event) error {
	if event == nil {
		o.logger.Warn("Attempt to create nil outbox event")
		return merrors.InvalidArgument("outbox: nil event")
	}

	if err := o.repo.Insert(ctx, event, nil); err != nil {
		if mongo.IsDuplicateKeyError(err) {
			o.logger.Warn("Duplicate outbox event id", zap.String("event_id", event.EventID))
			return merrors.DataConflict("outbox event with this id already exists")
		}
		o.logger.Warn("Failed to create outbox event", zap.Error(err))
		return err
	}

	o.logger.Debug("Outbox event created", zap.String("event_id", event.EventID), zap.String("subject", event.Subject))
	return nil
}

func (o *mongoStore) ListPending(ctx context.Context, limit int) ([]*Event, error) {
	limit64 := int64(limit)
	query := repository.Query().
		Filter(repository.Field("status"), StatusPending).
		Limit(&limit64).
		Sort(repository.Field("createdAt"), true)

	events := make([]*Event, 0)
	err := o.repo.FindManyByFilter(ctx, query, func(cur *mongo.Cursor) error {
		doc := &Event{}
		if err := cur.Decode(doc); err != nil {
			return err
		}
		events = append(events, doc)
		return nil
	})
	if err != nil {
		o.logger.Warn("Failed to list pending outbox events", zap.Error(err))
		return nil, err
	}

	return events, nil
}

func (o *mongoStore) MarkSent(ctx context.Context, eventRef bson.ObjectID, sentAt time.Time) error {
	if eventRef.IsZero() {
		return merrors.InvalidArgument("outbox: zero event id")
	}

	patch := repository.Patch().
		Set(repository.Field("status"), StatusSent).
		Set(repository.Field("sentAt"), sentAt)
	return o.repo.Patch(ctx, eventRef, patch)
}

func (o *mongoStore) MarkFailed(ctx context.Context, eventRef bson.ObjectID) error {
	if eventRef.IsZero() {
		return merrors.InvalidArgument("outbox: zero event id")
	}

	patch := repository.Patch().Set(repository.Field("status"), StatusFailed)
	return o.repo.Patch(ctx, eventRef, patch)
}

func (o *mongoStore) IncrementAttempts(ctx context.Context, eventRef bson.ObjectID) error {
	if eventRef.IsZero() {
		return merrors.InvalidArgument("outbox: zero event id")
	}

	patch := repository.Patch().Inc(repository.Field("attempts"), 1)
	return o.repo.Patch(ctx, eventRef, patch)
}