package models

import (
	"errors"
	"fmt"
	"time"

	"github.com/openmeterio/openmeter/pkg/clock"
	"github.com/openmeterio/openmeter/pkg/equal"
)

type ManagedUniqueResource struct {
	NamespacedModel `json:",inline" mapstructure:",squash"`
	ManagedModel    `json:",inline" mapstructure:",squash"`

	// ID is the unique identifier for Resource.
	ID string `json:"id"`

	// Key is the unique key for Resource.
	Key string `json:"key"`
}

type ManagedResource struct {
	NamespacedModel `json:",inline" mapstructure:",squash"`
	ManagedModel    `json:",inline" mapstructure:",squash"`

	// ID is the unique identifier for Resource.
	ID          string  `json:"id"`
	Description *string `json:"description,omitempty"`
	Name        string  `json:"name"`
}

func (m ManagedResource) GetID() string {
	return m.ID
}

func (m ManagedResource) GetDescription() *string {
	return m.Description
}

func (m ManagedResource) GetName() string {
	return m.Name
}

type ManagedResourceInput struct {
	ID          string
	Namespace   string
	CreatedAt   time.Time
	UpdatedAt   time.Time
	DeletedAt   *time.Time
	Name        string
	Description *string
}

func (r ManagedResourceInput) Validate() error {
	if r.ID == "" {
		return errors.New("id is required")
	}

	if r.Namespace == "" {
		return errors.New("namespace is required")
	}

	if r.CreatedAt.IsZero() {
		return errors.New("created at is required")
	}

	if r.UpdatedAt.IsZero() {
		return errors.New("updated at is required")
	}

	return nil
}

func NewManagedResource(input ManagedResourceInput) ManagedResource {
	return ManagedResource{
		ID: input.ID,
		NamespacedModel: NamespacedModel{
			Namespace: input.Namespace,
		},
		ManagedModel: ManagedModel{
			CreatedAt: input.CreatedAt.UTC(),
			UpdatedAt: input.UpdatedAt.UTC(),
			DeletedAt: func() *time.Time {
				if input.DeletedAt == nil {
					return nil
				}

				deletedAt := input.DeletedAt.UTC()

				return &deletedAt
			}(),
		},
		Name:        input.Name,
		Description: input.Description,
	}
}

func (r ManagedResource) Validate() error {
	if err := r.NamespacedModel.Validate(); err != nil {
		return fmt.Errorf("error validating namespaced model: %w", err)
	}

	if err := r.ManagedModel.Validate(); err != nil {
		return fmt.Errorf("error validating managed model: %w", err)
	}

	if r.ID == "" {
		return errors.New("id is required")
	}

	if r.Name == "" {
		return errors.New("name is required")
	}

	return nil
}

type ManagedModel struct {
	CreatedAt time.Time `json:"createdAt"`
	// After creation the entity is considered updated.
	UpdatedAt time.Time `json:"updatedAt"`
	// Time of soft delete. If not null, the entity is considered deleted.
	DeletedAt *time.Time `json:"deletedAt,omitempty"`
}

func (m ManagedModel) Validate() error {
	if m.CreatedAt.IsZero() {
		return errors.New("created at is required")
	}

	if m.UpdatedAt.IsZero() {
		return errors.New("updated at is required")
	}

	return nil
}

func (m ManagedModel) IsDeleted() bool {
	return m.IsDeletedAt(clock.Now())
}

func (m ManagedModel) IsDeletedAt(t time.Time) bool {
	if m.DeletedAt == nil {
		return false
	}

	return !m.DeletedAt.After(t)
}

func (m ManagedModel) Equal(other ManagedModel) bool {
	if !m.CreatedAt.Equal(other.CreatedAt) {
		return false
	}

	if !m.UpdatedAt.Equal(other.UpdatedAt) {
		return false
	}

	if !equal.PtrEqual(m.DeletedAt, other.DeletedAt) {
		return false
	}

	return true
}

func (m ManagedModel) GetCreatedAt() time.Time {
	return m.CreatedAt
}

func (m ManagedModel) GetUpdatedAt() time.Time {
	return m.UpdatedAt
}

func (m ManagedModel) GetDeletedAt() *time.Time {
	return m.DeletedAt
}

type ManagedModelWithID struct {
	ManagedModel `json:",inline" mapstructure:",squash"`
	ID           string `json:"id"`
}

func (m ManagedModelWithID) GetID() string {
	return m.ID
}

func (m ManagedModelWithID) Equal(other ManagedModelWithID) bool {
	if m.ID != other.ID {
		return false
	}

	return m.ManagedModel.Equal(other.ManagedModel)
}

func (m ManagedModelWithID) Validate() error {
	if m.ID == "" {
		return errors.New("id is required")
	}

	return nil
}

type NamespacedModel struct {
	Namespace string `json:"namespace"`
}

func (m NamespacedModel) Validate() error {
	if m.Namespace == "" {
		return errors.New("namespace is required")
	}

	return nil
}

func (m NamespacedModel) GetNamespace() string {
	return m.Namespace
}

type Address struct {
	Country     *CountryCode `json:"country,omitempty"`
	PostalCode  *string      `json:"postalCode,omitempty"`
	State       *string      `json:"state,omitempty"`
	City        *string      `json:"city,omitempty"`
	Line1       *string      `json:"line1,omitempty"`
	Line2       *string      `json:"line2,omitempty"`
	PhoneNumber *string      `json:"phoneNumber,omitempty"`
}

// [ISO 3166-1](https://www.iso.org/iso-3166-country-codes.html) alpha-2 country code.
type CountryCode string

// VersionedModel represents a versionable entity. With each new version the sequence is incremented
// while the key remains the same. Key + Version uniquely identifies an entity.
type VersionedModel struct {
	// Key is the unique identifier of the entity across its versions.
	// Might be generated by the system or provided by the user.
	Key string `json:"key,omitempty"`
	// Version is the integer sequential version of the entity, starting from 1.
	Version int `json:"version,omitempty"`
}