package controllers

import (
	"context"
	"errors"
	"regexp"

	"git.golem15.com/golem15/sm-user-plugin/models"
	"git.golem15.com/golem15/summercms/modules/cabana"
	"gorm.io/gorm"
)

// organisationSlugPattern is the PHP alpha_dash rule on the slug, kept to
// ASCII. lagoon.Validate has no alpha_dash token, so the Form before-hooks
// check it.
var organisationSlugPattern = regexp.MustCompile(`^[a-zA-Z0-9_-]+$`)

// membersRelation is the organisation's hasMany relation to its users.
const membersRelation = "members"

// organisationsAdminController is the Winter Organisations backend
// controller: the list, the form with the avatar, and the members relation
// manager. The screen and every write need golem15.users.access_users, as in
// PHP.
//
// The members manager sets and clears users.organisation_id and nothing
// else. It never writes users_groups.
type organisationsAdminController struct {
	app appAccess
}

func (organisationsAdminController) ID() string { return "golem15.user.organisations" }

func (organisationsAdminController) ModelName() string { return `Golem15\User\Models\Organisation` }

func (organisationsAdminController) ConfigDir() string { return "controllers/organisations" }

func (organisationsAdminController) RequiredPermissions() []string {
	return []string{PermissionAccessUsers}
}

func (organisationsAdminController) NewRecord() any { return &models.Organisation{} }

// FormBeforeCreate and FormBeforeUpdate check the slug's characters.
func (c organisationsAdminController) FormBeforeCreate(ctx context.Context, model any) error {
	return c.requireSlugFormat(ctx, model)
}

func (c organisationsAdminController) FormBeforeUpdate(ctx context.Context, model any) error {
	return c.requireSlugFormat(ctx, model)
}

// requireSlugFormat answers 422 on slug when it holds anything but letters,
// digits, underscore and hyphen. An empty slug is left to the required rule.
func (c organisationsAdminController) requireSlugFormat(ctx context.Context, model any) error {
	organisation, ok := model.(*models.Organisation)
	if !ok || organisation == nil {
		return errors.New("organisations admin: form model is not an organisation")
	}
	if organisation.Slug == "" || organisationSlugPattern.MatchString(organisation.Slug) {
		return nil
	}
	message := "The slug may only contain letters, numbers, dashes and underscores."
	if tr := c.app.translator(); tr != nil {
		const key = "golem15.user::lang.organisation.slug_invalid"
		if text := tr.Get(ctx, key, nil); text != "" && text != key {
			message = text
		}
	}
	return &cabana.ValidationError{Details: map[string]any{"slug": []string{message}}}
}

// AdminRelationContracts declares the members relation manager: the users
// whose organisation_id is the organisation. Linking sets the column and
// unlinking clears it; the column is nullable, so a user is never deleted.
func (organisationsAdminController) AdminRelationContracts() []cabana.RelationContract {
	return []cabana.RelationContract{{
		Name:       membersRelation,
		Kind:       cabana.RelationHasMany,
		NewRelated: func() any { return &models.User{} },
		ForeignKey: "organisation_id",
		Columns: map[string]string{
			"name":  "name",
			"email": "email",
		},
	}}
}

// RelationExtendManageQuery fails closed: any relation name other than
// members has no candidates.
func (organisationsAdminController) RelationExtendManageQuery(_ context.Context, relation string, db *gorm.DB) *gorm.DB {
	if db == nil {
		return db
	}
	if relation != membersRelation {
		return db.Where("1 = 0")
	}
	return db
}

// FormBeforeDelete releases the members of the organisation in the delete's
// transaction: organisation_id and organisation_role are cleared, on
// deactivated users too, so the delete does not fail on the users foreign key
// and no user is deleted.
func (organisationsAdminController) FormBeforeDelete(ctx context.Context, model any) error {
	organisation, ok := model.(*models.Organisation)
	if !ok || organisation == nil {
		return errors.New("organisations admin: form model is not an organisation")
	}
	tx, ok := cabana.TxFromContext(ctx)
	if !ok {
		return errors.New("organisations admin: a delete needs its transaction")
	}
	return tx.Session(&gorm.Session{NewDB: true}).WithContext(ctx).Unscoped().
		Model(&models.User{}).Where("organisation_id = ?", organisation.ID).
		Updates(map[string]any{"organisation_id": nil, "organisation_role": nil}).Error
}