package models

import (
	"fmt"
	"strconv"
	"strings"
	"time"

	"gorm.io/gorm"
)

// The built-in entry types (D-05). Every other type is a menu item type of
// the framework's registry (signpost). PHP stored the link type as "link";
// the Winter import maps it to TypeURL.
const (
	// TypeURL is a link to the entry's stored URL.
	TypeURL = "url"
	// TypeDivider is a separator with no URL.
	TypeDivider = "divider"
)

// Builtin reports whether typ is a built-in entry type.
func Builtin(typ string) bool { return typ == TypeURL || typ == TypeDivider }

// MenuEntry is one entry of a menu, stored on golem15_menu_menu_entries: the
// PHP Golem15\Menu\Models\MenuEntry. Entries form a tree per menu through
// parent_id and are ordered by sort_order within their parent. The nest
// columns are kept for the PHP schema; nothing reads them.
type MenuEntry struct {
	ID          uint       `gorm:"column:id;primaryKey"`
	MenuID      uint       `gorm:"column:menu_id"`
	Menu        *Menu      `gorm:"foreignKey:MenuID" json:"-"`
	ParentID    *uint      `gorm:"column:parent_id"`
	Parent      *MenuEntry `gorm:"foreignKey:ParentID" json:"-"`
	NestLeft    *int       `gorm:"column:nest_left"`
	NestRight   *int       `gorm:"column:nest_right"`
	NestDepth   *int       `gorm:"column:nest_depth"`
	SortOrder   *int       `gorm:"column:sort_order"`
	Type        string     `gorm:"column:type"`
	Title       *string    `gorm:"column:title"`
	URL         *string    `gorm:"column:url"`
	URLPattern  *string    `gorm:"column:url_pattern"`
	Reference   *string    `gorm:"column:reference"`
	Code        *string    `gorm:"column:code"`
	Icon        *string    `gorm:"column:icon"`
	CSSClass    *string    `gorm:"column:css_class"`
	Target      *string    `gorm:"column:target"`
	IsPublished *bool      `gorm:"column:is_published"`
	CreatedAt   *time.Time `gorm:"column:created_at"`
	UpdatedAt   *time.Time `gorm:"column:updated_at"`

	// requestedMenuID is the menu a save asked for when BeforeSave replaced
	// it with the parent's menu (see RequestedMenuID).
	requestedMenuID uint
}

func (MenuEntry) TableName() string { return "golem15_menu_menu_entries" }

// MorphName is the PHP class string of the model.
func (MenuEntry) MorphName() string { return `Golem15\Menu\Models\MenuEntry` }

// Fillable is the list an admin save may set. The nest columns and
// sort_order are not: the save hook and the reorder page set them.
func (MenuEntry) Fillable() []string {
	return []string{"menu_id", "parent_id", "type", "title", "url", "url_pattern", "reference", "code", "icon", "css_class", "target", "is_published"}
}

// Rules require a type; the admin controller checks the type, URL, target,
// menu and parent beyond that.
func (MenuEntry) Rules() map[string]string {
	return map[string]string{"type": "required"}
}

// BeforeSave ports the PHP beforeSave: the nest columns become 0 when unset,
// an entry with a parent takes the parent's menu, and an entry without a
// sort_order goes after the menu's last one. A missing title is stored empty
// (dividers have none) and a missing published flag is the PHP default true.
// When the entry named another menu than its parent's, RequestedMenuID
// reports the menu it named; the admin refuses such a save.
func (e *MenuEntry) BeforeSave(tx *gorm.DB) error {
	e.requestedMenuID = 0
	zero := func(p **int) {
		if *p == nil {
			v := 0
			*p = &v
		}
	}
	zero(&e.NestLeft)
	zero(&e.NestRight)
	zero(&e.NestDepth)
	if e.Title == nil {
		empty := ""
		e.Title = &empty
	}
	if e.IsPublished == nil {
		on := true
		e.IsPublished = &on
	}
	db := tx.Session(&gorm.Session{NewDB: true})
	if e.ParentID != nil && *e.ParentID != 0 {
		var menuIDs []uint
		if err := db.Model(&MenuEntry{}).Where("id = ?", *e.ParentID).Limit(1).Pluck("menu_id", &menuIDs).Error; err != nil {
			return err
		}
		if len(menuIDs) > 0 && menuIDs[0] != 0 {
			if e.MenuID != 0 && e.MenuID != menuIDs[0] {
				e.requestedMenuID = e.MenuID
			}
			e.MenuID = menuIDs[0]
		}
	}
	if e.SortOrder == nil {
		var max *int
		if err := db.Model(&MenuEntry{}).Where("menu_id = ?", e.MenuID).Select("MAX(sort_order)").Scan(&max).Error; err != nil {
			return err
		}
		next := 1
		if max != nil {
			next = *max + 1
		}
		e.SortOrder = &next
	}
	return nil
}

// RequestedMenuID is the menu the last save of e named when BeforeSave
// replaced it with the parent's menu: the parent belongs to another menu.
// It is 0 when the entry named no menu or its parent's.
func (e *MenuEntry) RequestedMenuID() uint { return e.requestedMenuID }

// Text is the value of an optional text column, "" when null.
func Text(s *string) string {
	if s == nil {
		return ""
	}
	return *s
}

func init() {
	Register(MenuEntry{})
}

// FilterMenu is the config_filter.yaml scope of the menu filter.
const FilterMenu = "FilterMenu"

// FilterScopes lists the scopes the list filters may name.
func (MenuEntry) FilterScopes() []string { return []string{FilterMenu} }

// FilterScope narrows the list to the entries of the chosen menus.
func (MenuEntry) FilterScope(name string, db *gorm.DB, value any) *gorm.DB {
	if db == nil || name != FilterMenu {
		return db
	}
	ids := filterIDs(value)
	if len(ids) == 0 {
		return db
	}
	return db.Where("menu_id IN ?", ids)
}

// filterIDs reads one id or a list of ids from a filter value.
func filterIDs(value any) []uint64 {
	var raw []any
	switch v := value.(type) {
	case []any:
		raw = v
	case []string:
		for _, s := range v {
			raw = append(raw, s)
		}
	default:
		raw = []any{v}
	}
	var out []uint64
	for _, item := range raw {
		text := strings.TrimSpace(fmt.Sprint(item))
		if item == nil || text == "" {
			continue
		}
		if id, err := strconv.ParseUint(text, 10, 32); err == nil && id > 0 {
			out = append(out, id)
		}
	}
	return out
}