package models

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

	"git.golem15.com/golem15/summercms/modules/lagoon"
	"gorm.io/gorm"
)

// The kinds of a registry page (D-33): they decide the sitemap file group
// and the default structured data.
const (
	PageKindPage    = "page"
	PageKindOffer   = "offer"
	PageKindService = "service"
	PageKindLanding = "landing"
)

// PageKinds lists the kinds in form order.
var PageKinds = []string{PageKindPage, PageKindOffer, PageKindService, PageKindLanding}

// The origins of a registry page: entered in the admin, reported by the
// frontend server's route report, or created through MCP.
const (
	PageOriginManual   = "manual"
	PageOriginReported = "reported"
	PageOriginMCP      = "mcp"
)

// PageOrigins lists the origins in filter order.
var PageOrigins = []string{PageOriginManual, PageOriginReported, PageOriginMCP}

// Page is one frontend page of the page registry on golem15_seo_pages
// (D-33): a page the site serves itself (home, contact, an offer), with
// its address per locale, a kind, a name, a parent, the date its content
// last changed and a note. URL is the default-locale path; URLs holds the
// other locales' paths and Titles the other locales' names (a locale
// without a path has no version of the page). ReportedAt is the newest
// route report that named the page.
type Page struct {
	ID               uint                               `gorm:"column:id;primaryKey"`
	URL              string                             `gorm:"column:url"`
	URLs             lagoon.Jsonable[map[string]string] `gorm:"column:urls"`
	Title            string                             `gorm:"column:title"`
	Titles           lagoon.Jsonable[map[string]string] `gorm:"column:titles"`
	Kind             string                             `gorm:"column:kind"`
	Origin           string                             `gorm:"column:origin"`
	ParentID         *PageRef                           `gorm:"column:parent_id"`
	ContentUpdatedAt *lagoon.Date                       `gorm:"column:content_updated_at"`
	ReportedAt       *time.Time                         `gorm:"column:reported_at"`
	Note             string                             `gorm:"column:note"`
	CreatedAt        *time.Time                         `gorm:"column:created_at;autoCreateTime:false"`
	UpdatedAt        *time.Time                         `gorm:"column:updated_at;autoUpdateTime:false"`
}

// BeforeSave stamps UpdatedAt (and CreatedAt of a new row) in UTC on every
// save, the admin's and the API's. GORM's own timestamps use the process's
// local time, which a timestamp column stores as the wall clock: on a
// machine east of UTC that put the page's sitemap lastmod in the future.
func (p *Page) BeforeSave(*gorm.DB) error {
	now := time.Now().UTC()
	if p.CreatedAt == nil || p.CreatedAt.IsZero() {
		p.CreatedAt = &now
	}
	p.UpdatedAt = &now
	return nil
}

func (Page) TableName() string { return "golem15_seo_pages" }

// MorphName names a registry page in history.
func (Page) MorphName() string { return `Golem15\SEO\Models\Page` }

// Fillable lists the owner form's columns; the addresses and names per
// locale are saved by the plugin's form extension on the Pages screen.
func (*Page) Fillable() []string {
	return []string{"kind", "parent_id", "content_updated_at", "note"}
}

// Rules is empty: the Pages controller and the registry service check a
// page before a save (classes.CheckPage).
func (*Page) Rules() map[string]string { return map[string]string{} }

// NewPage is a page with the form's defaults: kind page, entered by hand,
// its content changed today.
func NewPage() Page {
	today := lagoon.DateOf(time.Now().UTC())
	return Page{
		URLs:             lagoon.Jsonable[map[string]string]{Data: map[string]string{}, Valid: true},
		Titles:           lagoon.Jsonable[map[string]string]{Data: map[string]string{}, Valid: true},
		Kind:             PageKindPage,
		Origin:           PageOriginManual,
		ContentUpdatedAt: &today,
	}
}

// LocaleURLs returns the page's path per locale: def (the default locale)
// with URL, then every other locale with a non-empty path.
func (p Page) LocaleURLs(def string) map[string]string {
	out := map[string]string{}
	for locale, path := range p.URLs.Get() {
		if path = strings.TrimSpace(path); path != "" && locale != def {
			out[locale] = path
		}
	}
	if u := strings.TrimSpace(p.URL); u != "" {
		out[def] = u
	}
	return out
}

// TitleIn returns the page's name in locale, the default-locale name when
// that locale has none.
func (p Page) TitleIn(locale string) string {
	if t := strings.TrimSpace(p.Titles.Get()[locale]); t != "" {
		return t
	}
	return p.Title
}

// PageRef is a registry page id held by another page (its parent). The
// admin's parent dropdown posts it as text, which UnmarshalText reads; ""
// is 0, the top level.
type PageRef uint

// UnmarshalText reads a page id written as text.
func (r *PageRef) UnmarshalText(b []byte) error {
	text := strings.TrimSpace(string(b))
	if text == "" {
		*r = 0
		return nil
	}
	n, err := strconv.ParseUint(text, 10, 64)
	if err != nil {
		return fmt.Errorf("models: page id %q is not a number", b)
	}
	*r = PageRef(n)
	return nil
}

// Parent returns the parent page's id, 0 at the top level.
func (p Page) Parent() uint {
	if p.ParentID == nil {
		return 0
	}
	return uint(*p.ParentID)
}

// IDText is the page's id as text.
func (p Page) IDText() string { return strconv.FormatUint(uint64(p.ID), 10) }

// KnownPageKind reports whether kind is one of PageKinds.
func KnownPageKind(kind string) bool {
	for _, k := range PageKinds {
		if k == kind {
			return true
		}
	}
	return false
}

// The filter scopes of the Pages list (UI-SPEC C21).
const (
	FilterPageKind    = "FilterPageKind"
	FilterPageOrigin  = "FilterPageOrigin"
	FilterPageMissing = "FilterPageMissing"
	MissingOnly       = "only"
	MissingHide       = "hide"
)

// FilterScopes lists the Pages list's filter scopes.
func (Page) FilterScopes() []string {
	return []string{FilterPageKind, FilterPageOrigin, FilterPageMissing}
}

// MissingSQL is true for a reported page the newest route report did not
// name: its reported_at is older than the settings' routes_reported_at.
const MissingSQL = `(golem15_seo_pages.origin = 'reported' AND EXISTS (SELECT 1 FROM golem15_seo_settings s WHERE s.id = 1 AND s.routes_reported_at IS NOT NULL AND (golem15_seo_pages.reported_at IS NULL OR golem15_seo_pages.reported_at < s.routes_reported_at)))`

// FilterScope narrows the Pages list; an unknown value matches nothing.
func (Page) FilterScope(name string, db *gorm.DB, value any) *gorm.DB {
	if db == nil {
		return db
	}
	s, _ := value.(string)
	switch name {
	case FilterPageKind:
		if !KnownPageKind(s) {
			return db.Where("1 = 0")
		}
		return db.Where("golem15_seo_pages.kind = ?", s)
	case FilterPageOrigin:
		for _, o := range PageOrigins {
			if o == s {
				return db.Where("golem15_seo_pages.origin = ?", s)
			}
		}
		return db.Where("1 = 0")
	case FilterPageMissing:
		switch s {
		case MissingOnly:
			return db.Where(MissingSQL)
		case MissingHide:
			return db.Where("NOT " + MissingSQL)
		}
		return db.Where("1 = 0")
	}
	return db
}

func init() {
	Register(Page{})
}