package manager

import (
	"context"
	"fmt"
	"io"
	"strconv"

	"github.com/stashapp/stash/pkg/logger"
)

type ImportDuplicateEnum string

const (
	ImportDuplicateEnumIgnore    ImportDuplicateEnum = "IGNORE"
	ImportDuplicateEnumOverwrite ImportDuplicateEnum = "OVERWRITE"
	ImportDuplicateEnumFail      ImportDuplicateEnum = "FAIL"
)

var AllImportDuplicateEnum = []ImportDuplicateEnum{
	ImportDuplicateEnumIgnore,
	ImportDuplicateEnumOverwrite,
	ImportDuplicateEnumFail,
}

func (e ImportDuplicateEnum) IsValid() bool {
	switch e {
	case ImportDuplicateEnumIgnore, ImportDuplicateEnumOverwrite, ImportDuplicateEnumFail:
		return true
	}
	return false
}

func (e ImportDuplicateEnum) String() string {
	return string(e)
}

func (e *ImportDuplicateEnum) UnmarshalGQL(v interface{}) error {
	str, ok := v.(string)
	if !ok {
		return fmt.Errorf("enums must be strings")
	}

	*e = ImportDuplicateEnum(str)
	if !e.IsValid() {
		return fmt.Errorf("%s is not a valid ImportDuplicateEnum", str)
	}
	return nil
}

func (e ImportDuplicateEnum) MarshalGQL(w io.Writer) {
	fmt.Fprint(w, strconv.Quote(e.String()))
}

type importer interface {
	PreImport(ctx context.Context) error
	PostImport(ctx context.Context, id int) error
	Name() string
	FindExistingID(ctx context.Context) (*int, error)
	Create(ctx context.Context) (*int, error)
	Update(ctx context.Context, id int) error
}

func performImport(ctx context.Context, i importer, duplicateBehaviour ImportDuplicateEnum) error {
	if err := i.PreImport(ctx); err != nil {
		return err
	}

	// try to find an existing object with the same name
	name := i.Name()
	existing, err := i.FindExistingID(ctx)
	if err != nil {
		return fmt.Errorf("error finding existing objects: %v", err)
	}

	var id int

	if existing != nil {
		if duplicateBehaviour == ImportDuplicateEnumFail {
			return fmt.Errorf("existing object with name '%s'", name)
		} else if duplicateBehaviour == ImportDuplicateEnumIgnore {
			logger.Infof("Skipping existing object %q", name)
			return nil
		}

		// must be overwriting
		id = *existing
		if err := i.Update(ctx, id); err != nil {
			return fmt.Errorf("error updating existing object: %v", err)
		}
	} else {
		// creating
		createdID, err := i.Create(ctx)
		if err != nil {
			return fmt.Errorf("error creating object: %v", err)
		}

		id = *createdID
	}

	if err := i.PostImport(ctx, id); err != nil {
		return err
	}

	return nil
}