package pact

import (
	"context"
	"time"
)

// ContentDescriptor describes the records behind a menu item type, for
// consumers that work on every content type at once: sitemaps, search
// indexers, audit tools, metadata editors. A type sets it in
// MenuItemType.Content; a type without one takes no part and behaves as
// before.
//
// Controller is the ID of the admin controller whose form edits the
// records, "" when none does. Model is the records' morph type, the value
// RecordSaved and RecordDeleted carry (lagoon.MorphType), so an event maps to
// its content type with one lookup; it is required. Describe is required and
// describes one record by id. Records pages through the records and Match
// maps a public path to a record; both are optional.
//
// The functions read through cabana.TxFromContext(ctx) when ctx carries a
// write transaction, so code running inside a save (a form extension's Save,
// for example) sees the values the save has just written.
type ContentDescriptor struct {
	Controller string
	Model      string
	Records    func(ctx context.Context, in ContentList) (ContentPage, error)          `json:"-"`
	Describe   func(ctx context.Context, in ContentDescribe) (*ContentRecord, error)   `json:"-"`
	Match      func(ctx context.Context, in ContentMatch) (*ContentMatchResult, error) `json:"-"`
}

// ContentList is what ContentDescriptor.Records receives. Pattern is the URL
// pattern already layered by the registry (the host's override, else the
// type's default). After is the ID of the last record of the previous page,
// "" for the first page; Limit is the page size the caller wants (the type
// may cap it). UnprefixedLocale names the locale whose URLs carry no locale
// prefix; "" leaves the choice to the type.
type ContentList struct {
	Pattern          string
	After            string
	Limit            int
	UnprefixedLocale string
}

// ContentPage is one page of records in a stable order. Next is the After of
// the following page, "" on the last page.
type ContentPage struct {
	Records []ContentRecord
	Next    string
}

// ContentDescribe is what ContentDescriptor.Describe receives: the record's
// ID, the layered URL pattern and the unprefixed locale, as in ContentList.
type ContentDescribe struct {
	ID               string
	Pattern          string
	UnprefixedLocale string
}

// ContentRecord describes one record. ID is its primary key as text,
// Published whether visitors can see it, LastMod its last change (nil when
// unknown). Locales lists the record per locale in the site's locale order.
type ContentRecord struct {
	ID        string
	Published bool
	LastMod   *time.Time
	Locales   []ContentLocale
}

// ContentLocale is a record in one locale. URL is its public path, "" when
// the locale or the host has no public page for it. Title, Description and
// Image (a URL) are the record's own defaults for page metadata; Words is the
// body's word count, nil when the type has no body.
type ContentLocale struct {
	Locale      string
	URL         string
	Title       string
	Description string
	Image       string
	Words       *int
}

// ContentMatch is what ContentDescriptor.Match receives: a public path (no
// query, no host), the layered URL pattern and the unprefixed locale.
type ContentMatch struct {
	Path             string
	Pattern          string
	UnprefixedLocale string
}

// ContentMatchResult names the record a path belongs to and the locale the
// path addresses. Exact is false when the path names the record but a
// segment does not match it (another category, a stale locale prefix, a
// slug of another locale): the caller may then redirect to the record's URL.
// Match answers nil when the path names no record visitors can see.
type ContentMatchResult struct {
	ID     string
	Locale string
	Exact  bool
}