package storage

import (
	"context"
	"errors"
	"fmt"
	"local/dndex/storage/driver"
	"local/dndex/storage/entity"
	"local/dndex/storage/operator"

	"go.mongodb.org/mongo-driver/bson"
)

type Graph struct {
	driver driver.Driver
}

func NewGraph(path ...string) Graph {
	return Graph{
		driver: driver.New(path...),
	}
}

func (g Graph) Search(ctx context.Context, namespace string, nameContains string) ([]entity.One, error) {
	filter := operator.Regex{Key: entity.Name, Value: fmt.Sprintf(".*%s.*", nameContains)}
	return g.find(ctx, namespace, filter)
}

func (g Graph) ListCaseInsensitive(ctx context.Context, namespace string, from ...string) ([]entity.One, error) {
	filter := operator.CaseInsensitives{Key: entity.Name, Values: from}
	return g.find(ctx, namespace, filter)
}

func (g Graph) Get(ctx context.Context, namespace, id string) (entity.One, error) {
	ones, err := g.find(ctx, namespace, bson.M{entity.ID: id})
	if err != nil {
		return entity.One{}, err
	}
	if len(ones) == 0 {
		return entity.One{}, errors.New("not found")
	}
	if len(ones) > 1 {
		return entity.One{}, errors.New("primary key collision detected")
	}
	return ones[0], nil
}

func (g Graph) List(ctx context.Context, namespace string, from ...string) ([]entity.One, error) {
	filter := operator.NewFilterIn(entity.Name, from)
	return g.find(ctx, namespace, filter)
}

func (g Graph) find(ctx context.Context, namespace string, filter interface{}) ([]entity.One, error) {
	ch, err := g.driver.Find(ctx, namespace, filter)
	if err != nil {
		return nil, err
	}
	return g.gatherOnes(ctx, ch)
}

func (g Graph) gatherOnes(ctx context.Context, ch <-chan bson.Raw) ([]entity.One, error) {
	var ones []entity.One
	for one := range ch {
		var o entity.One
		if err := bson.Unmarshal(one, &o); err != nil {
			return nil, err
		}
		ones = append(ones, o)
	}
	return ones, nil
}

func (g Graph) Insert(ctx context.Context, namespace string, one entity.One) error {
	if one.Name == "" || one.ID == "" {
		return errors.New("cannot create document without both name and id")
	}
	if ones, err := g.ListCaseInsensitive(ctx, namespace, one.Name); err != nil {
		return err
	} else if len(ones) > 0 {
		return fmt.Errorf("collision on primary key when case insensitive: cannot create %q because %+v exists", one.Name, ones)
	}
	return g.driver.Insert(ctx, namespace, one)
}

func (g Graph) Update(ctx context.Context, namespace string, one, modify interface{}) error {
	return g.driver.Update(ctx, namespace, one, modify)
}

func (g Graph) Delete(ctx context.Context, namespace string, filter interface{}) error {
	return g.driver.Delete(ctx, namespace, filter)
}