package wmo

import (
	"context"
	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
	ct "gogs.mikescher.com/BlackForestBytes/goext/cursortoken"
	"gogs.mikescher.com/BlackForestBytes/goext/langext"
	"reflect"
)

type fullTypeRef[TData any] struct {
	IsPointer      bool
	Kind           reflect.Kind
	Type           reflect.Type
	UnderlyingType reflect.Type
	Name           string
	Index          []int
}

type Coll[TData any] struct {
	coll        *mongo.Collection
	dataTypeMap map[string]fullTypeRef[TData]
}

func (c *Coll[TData]) Collection() *mongo.Collection {
	return c.coll
}

func (c *Coll[TData]) Name() string {
	return c.coll.Name()
}

func (c *Coll[TData]) Indexes() mongo.IndexView {
	return c.coll.Indexes()
}

func (c *Coll[TData]) Drop(ctx context.Context) error {
	return c.coll.Drop(ctx)
}

func (c *Coll[TData]) FindOne(ctx context.Context, filter any) (TData, error) {
	var res TData

	err := c.coll.FindOne(ctx, filter).Decode(&res)
	if err != nil {
		return *new(TData), err
	}

	return res, nil
}

func (c *Coll[TData]) FindOneOpt(ctx context.Context, filter any) (*TData, error) {
	var res TData

	err := c.coll.FindOne(ctx, filter).Decode(&res)
	if err == mongo.ErrNoDocuments {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}

	return &res, nil
}

func (c *Coll[TData]) FindOneByID(ctx context.Context, id any) (TData, error) {
	var res TData

	err := c.coll.FindOne(ctx, bson.M{"_id": id}).Decode(&res)
	if err != nil {
		return *new(TData), err
	}

	return res, nil
}

func (c *Coll[TData]) FindOneOptByID(ctx context.Context, id any) (*TData, error) {
	var res TData

	err := c.coll.FindOne(ctx, bson.M{"_id": id}).Decode(&res)
	if err == mongo.ErrNoDocuments {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}

	return &res, nil
}

func (c *Coll[TData]) Find(ctx context.Context, filter any, opts ...*options.FindOptions) ([]TData, error) {
	cursor, err := c.coll.Find(ctx, filter, opts...)
	if err != nil {
		return nil, err
	}

	res := make([]TData, 0, cursor.RemainingBatchLength())
	err = cursor.All(ctx, &res)
	if err != nil {
		return nil, err
	}

	return res, nil
}

func (c *Coll[TData]) Aggregate(ctx context.Context, pipeline mongo.Pipeline, opts ...*options.AggregateOptions) ([]TData, error) {
	cursor, err := c.coll.Aggregate(ctx, pipeline, opts...)
	if err != nil {
		return nil, err
	}

	res := make([]TData, 0, cursor.RemainingBatchLength())
	err = cursor.All(ctx, &res)
	if err != nil {
		return nil, err
	}

	return res, nil
}

func (c *Coll[TData]) ReplaceOne(ctx context.Context, id any, value TData) error {
	_, err := c.coll.UpdateOne(ctx, bson.M{"_id": id}, value)
	if err != nil {
		return err
	}

	return nil
}

func (c *Coll[TData]) UpdateOne(ctx context.Context, id any, updateQuery any) error {
	_, err := c.coll.UpdateOne(ctx, bson.M{"_id": id}, updateQuery)
	if err != nil {
		return err
	}

	return nil
}

func (c *Coll[TData]) UpdateOneAndReturn(ctx context.Context, id any, updateQuery any) (TData, error) {
	_, err := c.coll.UpdateOne(ctx, bson.M{"_id": id}, updateQuery)
	if err != nil {
		return *new(TData), err
	}

	var res TData

	err = c.coll.FindOne(ctx, bson.M{"_id": id}).Decode(&res)
	if err != nil {
		return *new(TData), err
	}

	return res, nil
}

func (c *Coll[TData]) DeleteOne(ctx context.Context, id any) error {
	_, err := c.coll.DeleteOne(ctx, bson.M{"_id": id})
	if err != nil {
		return err
	}

	return nil
}

func (c *Coll[TData]) List(ctx context.Context, filter ct.Filter, pageSize *int, inTok ct.CursorToken) ([]TData, ct.CursorToken, error) {
	if inTok.Mode == ct.CTMEnd {
		return make([]TData, 0), ct.End(), nil
	}

	pipeline := filter.FilterQuery()

	sortPrimary, sortDirPrimary, sortSecondary, sortDirSecondary := filter.Pagination()

	paginationPipeline, err := CreatePagination(c, inTok, sortPrimary, sortDirPrimary, sortSecondary, sortDirSecondary, pageSize)
	if err != nil {
		return nil, ct.CursorToken{}, err
	}

	pipeline = append(pipeline, paginationPipeline...)

	cursor, err := c.coll.Aggregate(ctx, pipeline)
	if err != nil {
		return nil, ct.CursorToken{}, err
	}

	entities := make([]TData, 0, cursor.RemainingBatchLength()+1)
	for (pageSize == nil || len(entities) != *pageSize) && cursor.Next(ctx) {
		var entry TData
		err = cursor.Decode(&entry)
		if err != nil {
			return nil, ct.CursorToken{}, err
		}
		entities = append(entities, entry)
	}

	if pageSize == nil || len(entities) <= *pageSize || !cursor.TryNext(ctx) {
		return entities, ct.End(), nil
	}

	last := entities[len(entities)-1]

	nextToken, _ := c.createToken(sortPrimary, sortDirPrimary, sortSecondary, sortDirSecondary, last, pageSize)

	return entities, nextToken, nil
}

func (c *Coll[TData]) createToken(fieldPrimary string, dirPrimary ct.SortDirection, fieldSecondary *string, dirSecondary *ct.SortDirection, lastEntity TData, pageSize *int) (ct.CursorToken, error) {

	valuePrimary, err := c.getFieldValueAsTokenString(lastEntity, fieldPrimary)
	if err != nil {
		return ct.CursorToken{}, err
	}

	valueSeconary := ""
	if fieldSecondary != nil && dirSecondary != nil {
		valueSeconary, err = c.getFieldValueAsTokenString(lastEntity, *fieldSecondary)
		if err != nil {
			return ct.CursorToken{}, err
		}
	}

	return ct.CursorToken{
		Mode:           ct.CTMNormal,
		ValuePrimary:   valuePrimary,
		ValueSecondary: valueSeconary,
		Direction:      dirPrimary,
		PageSize:       langext.Coalesce(pageSize, 0),
		Extra:          ct.Extra{},
	}, nil
}