package models

import (
	"time"

	"gorm.io/gorm"
)

// The writers of a history entry (D-13).
const (
	ViaAdmin  = "admin"
	ViaMCP    = "mcp"
	ViaImport = "import"
	ViaAuto   = "auto"
	ViaUndo   = "undo"
)

// The subjects of a history entry.
const (
	SubjectEntry    = "entry"
	SubjectRule     = "rule"
	SubjectRedirect = "redirect"
	SubjectRobots   = "robots"
	SubjectSettings = "settings"
	SubjectNotFound = "notfound"
	// SubjectPage is a page of the page registry (D-33).
	SubjectPage = "page"
	// SubjectAutolink is a phrase of the auto-link table (D-82).
	SubjectAutolink = "autolink"
)

// Revision is one recorded SEO change on golem15_seo_revisions (D-13): who
// made it (AuthorID and AuthorLabel, the label kept when the administrator
// is gone), through what (Via), on which object (SubjectKind and
// SubjectID: an entry as "<model type>|<record id>|<locale>", a rule by
// id, settings as "1" or "type:<key>"), a readable description (What) and
// the changed fields only, before and after. A created object has no
// Before and a deleted one no After. BatchID groups the changes of one
// batch; UndoneAt marks an undone change.
type Revision struct {
	ID          uint       `gorm:"column:id;primaryKey"`
	BatchID     *string    `gorm:"column:batch_id"`
	AuthorID    *uint      `gorm:"column:author_id"`
	AuthorLabel string     `gorm:"column:author_label"`
	Via         string     `gorm:"column:via"`
	SubjectKind string     `gorm:"column:subject_kind"`
	SubjectID   string     `gorm:"column:subject_id"`
	What        string     `gorm:"column:what"`
	Before      JSONMap    `gorm:"column:before"`
	After       JSONMap    `gorm:"column:after"`
	UndoneAt    *time.Time `gorm:"column:undone_at"`
	UndoneByID  *uint      `gorm:"column:undone_by_id"`
	CreatedAt   time.Time  `gorm:"column:created_at"`
	// Change is the list's summary of the changed fields and ViaLabel the
	// via column's label, filled by the history controller.
	Change   string `gorm:"-:all;column:change"`
	ViaLabel string `gorm:"-:all;column:via_label"`
	Batch    string `gorm:"-:all;column:batch"`
}

func (Revision) TableName() string { return "golem15_seo_revisions" }

// Fillable is empty: history is written by the service only.
func (Revision) Fillable() []string { return []string{} }

// Rules is empty: history is never edited.
func (Revision) Rules() map[string]string { return map[string]string{} }

// FilterVia is the history list's via filter scope.
const FilterVia = "FilterVia"

// Vias lists the writers in display order.
var Vias = []string{ViaAdmin, ViaMCP, ViaImport, ViaAuto, ViaUndo}

func init() {
	Register(Revision{})
}

// FilterScopes lists the history list's filter scopes.
func (Revision) FilterScopes() []string { return []string{FilterVia} }

// FilterScope narrows the history list to one writer; an unknown value
// matches nothing.
func (Revision) FilterScope(name string, db *gorm.DB, value any) *gorm.DB {
	if db == nil || name != FilterVia {
		return db
	}
	s, _ := value.(string)
	for _, v := range Vias {
		if v == s {
			return db.Where("golem15_seo_revisions.via = ?", s)
		}
	}
	return db.Where("1 = 0")
}