package chrome

import (
	"fmt"
	"strings"
	"time"
)

// LinkLifetime is how long an emailed sign-in link works. It is
// keymaildev/signin's LinkTTL default, which every sign-in in the suite
// inherits: rastrillo's auth, Home's own flow and the keymail path all
// leave LinkTTL unset (checked 2026-10-01 at signin v0.1.1, rastrillo
// main 2fafa12 and v0.23.0, and Home 7a0f19c). The copy below says the
// number, so a sign-in that changes its lifetime must change this too, or
// the door and the email tell people something false.
const LinkLifetime = 15 * time.Minute

// DoorCopy is the door's words: the sign-in form, the check-your-email
// state, the signed-out page and the sign-in email. English is the
// suite's one copy set; a locale replaces the whole set through
// SignIn.Copy and SignInNotice.Copy, never a word at a time, so no app
// can drift from the others by overriding one line.
//
// The words are the copy deck in §9.2 of the shared-chrome spec
// (docs/superpowers/specs/2026-09-23-shared-chrome.md, on estilo's
// spec/shared-chrome branch), with Paul's later rulings noted where they
// apply. "§9.2" and "§10" below are that document's sections.
//
// Translations are estilo's follow-up, never an app's. English is the
// only set today. When the suite needs another locale, estilo adds its
// whole DoorCopy here, beside English, with a way to pick one by locale,
// and every app gets it on its next re-pin. An app passes Copy only a set
// estilo publishes; it never writes or edits one, or the one copy set
// fragments again the first time an app translates its own door.
//
// Slots are tokens, not Printf verbs: {app} is the app's name, and {link}
// (the email body only) is the sign-in link. A translation may drop or
// move a slot, or carry a literal "%", and still render as written.
type DoorCopy struct {
	// The form: heading (also the tab title's page), address label, the
	// one help line under the field, and the submit.
	Heading, AddressLabel, Help, Submit string
	// The sent state, which replaces the form: heading (and tab title),
	// body, and the link back to the form.
	SentHeading, SentBody, Again string
	// The signed-out page: the tab title's page, the heading, the body
	// ({app} is the app's name) and the Sign in button.
	SignedOutPage, SignedOutHeading, SignedOutBody, SignIn string
	// The sign-in email: subject ({app}) and body ({app} and {link}).
	EmailSubject, EmailBody string
}

// linkMinutes is LinkLifetime in words, so the number lives in one place.
var linkMinutes = fmt.Sprintf("%d minutes", int(LinkLifetime/time.Minute))

// English is the door's copy set (shared-chrome spec §9.2). The submit
// is "Sign in": Paul, 2026-10-01, ruled out "Email me a link". The hub is
// never named ("Home"); the suite is Oficina (Paul, 2026-09-23).
var English = DoorCopy{
	Heading:          "Sign in",
	AddressLabel:     "Email address",
	Help:             "We’ll email you a link that signs you in. It works once and expires in " + linkMinutes + ".",
	Submit:           "Sign in",
	SentHeading:      "Check your email",
	SentBody:         "If that address can sign in here, we’ve sent it a link. It works once and expires in " + linkMinutes + ".",
	Again:            "Use a different address",
	SignedOutPage:    "Signed out",
	SignedOutHeading: "You’re signed out",
	SignedOutBody:    "You’ve signed out of {app} on this device.",
	SignIn:           "Sign in",
	EmailSubject:     "Sign in to {app}",
	EmailBody:        "Here’s your link to sign in to {app}:\n\n{link}\n\nIt works once and expires in " + linkMinutes + ". If you didn’t ask for it, you can ignore this email.",
}

// signedOutBody names the app; with none it names the suite, as the hub's
// own signed-out page does.
func (c DoorCopy) signedOutBody(app string) string {
	if app == "" {
		app = "Oficina"
	}
	return fill(c.SignedOutBody, app, "")
}

// fill puts the app's name and the link into a copy string's {app} and
// {link} slots, in one pass: a name or link that itself contains a token
// is not filled again.
func fill(s, app, link string) string {
	return strings.NewReplacer("{app}", app, "{link}", link).Replace(s)
}

func copyOf(c *DoorCopy) DoorCopy {
	if c == nil {
		return English
	}
	return *c
}

// Title is a page's tab title: "<Page> · <App>" (shared-chrome spec
// §10), or whichever half is set when one is empty.
func Title(page, app string) string {
	page, app = strings.TrimSpace(page), strings.TrimSpace(app)
	switch {
	case page == "":
		return app
	case app == "":
		return page
	}
	return page + " · " + app
}

// The form's words, read by estilo-signin.
func (s SignIn) Heading() string      { return copyOf(s.Copy).Heading }
func (s SignIn) AddressLabel() string { return copyOf(s.Copy).AddressLabel }
func (s SignIn) Help() string         { return copyOf(s.Copy).Help }
func (s SignIn) Submit() string       { return copyOf(s.Copy).Submit }

// Page is the sign-in page's part of the tab title ("Sign in"), for a
// layout that appends the app's name itself; Title is the whole title.
func (s SignIn) Page() string  { return s.Heading() }
func (s SignIn) Title() string { return Title(s.Page(), s.App) }

// Sent is this door's check-your-email state: the door's heading and
// body, and "Use a different address" linking to again (the form,
// keeping the return; empty drops the link).
func (n SignInNotice) Sent(again string) SignInNotice {
	c := copyOf(n.Copy)
	n.Heading, n.Body, n.page, n.Link = c.SentHeading, c.SentBody, c.SentHeading, nil
	if again != "" {
		n.Link = &Link{Href: again, Label: c.Again}
	}
	return n
}

// SignedOut is this door's signed-out page: "You’re signed out", the
// sentence naming the app, and the primary Sign in linking to signin.
func (n SignInNotice) SignedOut(signin string) SignInNotice {
	c := copyOf(n.Copy)
	n.Heading, n.Body, n.page, n.Link = c.SignedOutHeading, c.signedOutBody(n.App), c.SignedOutPage, nil
	if signin != "" {
		n.Link = &Link{Href: signin, Label: c.SignIn}
	}
	return n
}

// Page is the notice's part of the tab title: the door's own for Sent and
// SignedOut ("Check your email", "Signed out"), otherwise the heading.
func (n SignInNotice) Page() string {
	if n.page != "" {
		return n.page
	}
	return n.Heading
}

// Title is the notice's whole tab title, "<Page> · <App>".
func (n SignInNotice) Title() string { return Title(n.Page(), n.App) }

// SignInEmail is this copy set's sign-in email for app: subject and body
// around link.
func (c DoorCopy) SignInEmail(app, link string) (subject, body string) {
	return c.MailSubject(app), c.MailBody(app)(link)
}

// MailSubject is the sign-in email's subject, "Sign in to <App>" in
// English. (Not EmailSubject: that is the field it reads.)
func (c DoorCopy) MailSubject(app string) string { return fill(c.EmailSubject, app, "") }

// MailBody renders the sign-in email's body around the link.
func (c DoorCopy) MailBody(app string) func(link string) string {
	return func(link string) string { return fill(c.EmailBody, app, link) }
}

// SignInEmail is the sign-in email for app in English: subject and body
// around link.
func SignInEmail(app, link string) (subject, body string) { return English.SignInEmail(app, link) }

// EmailSubject is the sign-in email's subject in English, "Sign in to
// <App>": what rastrillo's auth.Config.Subject takes.
func EmailSubject(app string) string { return English.MailSubject(app) }

// EmailBody renders the English sign-in email's body around the link: the
// shape keymaildev/signin's Flow.Body and rastrillo's auth.Config.Body
// take.
func EmailBody(app string) func(link string) string { return English.MailBody(app) }