package gallery

import (
	"fmt"
	"html/template"
	"regexp"

	"amadan.net/rastrillo/fiesta/example"
)

// The modal route: the modal idiom at the URL the idiom insists on.
// The modal example's frame shows the markup inside a widget; this is
// the same markup as a page of its own, demo-modal.html (modal.html is
// the modal example's page), linked from the Demos group and from that
// page.
//
// The document is the modal example's own, with Rastrillo's three
// deviations, each the difference between a sample and a page that
// exists: the backdrop holds a real screen (a page header and a box)
// instead of a bare heading, so there is something behind the panel;
// the panel's tabs link this page, so switching one keeps the modal
// open rather than landing on a route this tree does not serve; and
// Close returns to the Overview, since the backdrop's screen has no
// address of its own here, which the panel says. The panel stays a
// <dialog open>, never showModal()'d, as the example is.
//
// It is framed as a sample document is: the gallery's assets, noindex,
// frame.js first so a scheme the reader chose comes with them, and the
// padding rule, which leaves a page with a backdrop unpadded.

// modalHref is the modal route's address.
func (s *site) modalHref(theme, locale string) string {
	return s.href(theme, locale, "demo-modal.html")
}

var (
	// The example's backdrop, a page with one heading.
	modalBackdrop = regexp.MustCompile(`(?s)<div rst-backdrop inert>.*?</div>\s*</div>`)
	// The panel's tabs and its section, each rewritten whole.
	modalNav     = regexp.MustCompile(`(?s)<nav>.*?</nav>`)
	modalSection = regexp.MustCompile(`(?s)<section>.*?</section>`)
)

// modal builds one theme and locale's modal route.
func (s *site) modal(theme, locale string) ([]byte, error) {
	const name = "modal"
	e, ok := s.m.Entry(name)
	if !ok {
		return nil, fmt.Errorf("the manifest has no %s example to build the modal route from", name)
	}
	doc, err := example.Document(s.src, name, e.Default)
	if err != nil {
		return nil, err
	}
	say := func(id string) string { return template.HTMLEscapeString(s.say(locale, id)) }
	self := s.modalHref(theme, locale)
	overview := s.href(theme, locale, s.fileOf("overview"))
	steps := []struct {
		what string
		re   *regexp.Regexp
		with string
	}{
		{"the title", titleTag, "<title>" + template.HTMLEscapeString(s.say(locale, "gallery.title", "page", s.say(locale, "gallery.demos.modal"), "theme", theme)) + "</title>"},
		{"the backdrop", modalBackdrop, `<div rst-backdrop inert>
<main rst-page id="main">
<header rst-page-header>
  <div rst-page-header-titles>
    <h1>` + say("gallery.modal.settings") + `</h1>
    <p rst-page-header-sub>` + say("gallery.modal.sub") + `</p>
  </div>
</header>
<div rst-box-head><h2>` + say("gallery.modal.account") + `</h2></div>
<section rst-box><p>` + say("gallery.modal.own") + `</p></section>
</main>
</div>`},
		{"the panel's tabs", modalNav, `<nav>
      <a data-gallery-nav href="` + self + `" aria-current="page">` + say("gallery.modal.profile") + `</a>
      <a data-gallery-nav href="` + self + `">` + say("gallery.modal.billing") + `</a>
      <a data-gallery-nav href="` + self + `">` + say("gallery.modal.notifications") + `</a>
    </nav>`},
		{"the panel's section", modalSection, `<section>
      <a rst-modal-close data-gallery-nav href="` + overview + `" aria-label="` + say("gallery.modal.close") + `">✕</a>
      <h2 id="modal-title">` + say("gallery.modal.profile") + `</h2>
      <p>` + say("gallery.modal.body") + `</p>
      <p>` + say("gallery.modal.nojs") + `</p>
      <p>` + say("gallery.modal.inapp") + `</p>
      <p><a rst-btn data-gallery-nav href="` + overview + `">` + say("gallery.back") + `</a></p>
    </section>`},
	}
	for _, step := range steps {
		if n := len(step.re.FindAllStringIndex(doc, -1)); n != 1 {
			return nil, fmt.Errorf("%s/%s has %d of %s to rewrite, want one", name, e.Default, n, step.what)
		}
		doc = step.re.ReplaceAllLiteralString(doc, step.with)
	}
	framed, err := s.framed(doc, theme, locale, e, nil)
	if err != nil {
		return nil, fmt.Errorf("demo-modal.html: %w", err)
	}
	return []byte(framed), nil
}