package calls

import (
	"amadan.net/rastrillo/rastrillo/sessions"
	"errors"
	"html/template"
	"net/http"
	"net/url"

	"github.com/go-chi/chi/v5"
)

// followLink is GET /j/{token}: one 404 for unknown, revoked, ended or
// expired; otherwise one of three outcomes (spec §3.2). It is mounted
// outside the session group because the person is often not signed in.
func (a *app) followLink(w http.ResponseWriter, r *http.Request) {
	link, m, live, err := a.store.liveLink(r.Context(), chi.URLParam(r, "token"))
	if err != nil {
		a.logger.Error("calls: follow link", "err", err)
		a.ErrorPage(w, r, http.StatusInternalServerError, "")
		return
	}
	if !live {
		a.ErrorPage(w, r, http.StatusNotFound, "")
		return
	}
	id, signedIn := a.auth.SessionFrom(r)
	if !signedIn {
		a.setJoinCookie(w, link.TokenHash)
		if !m.RequireSignin {
			a.guestPage(w, r, m, chi.URLParam(r, "token"), "", "")
			return
		}
		http.Redirect(w, r, signinPath, http.StatusSeeOther)
		return
	}
	p, err := a.personForSession(r.Context(), sessions.Session{Subject: id.Address, Method: string(id.Method), AuthTime: id.AuthTime, At: id.At})
	if errors.Is(err, errHomeIdentity) {
		a.ErrorPage(w, r, http.StatusNotFound, "")
		return
	}
	if err != nil {
		a.logger.Error("calls: ensure person", "err", err)
		a.ErrorPage(w, r, http.StatusInternalServerError, "")
		return
	}
	if p.Anonymous && m.RequireSignin {
		a.setJoinCookie(w, link.TokenHash)
		http.Redirect(w, r, signinPath, 303)
		return
	}
	if !a.isMember(p) {
		// Via the link, not the meeting: this handler read the link
		// before it resolved the person, and a member may have replaced
		// it in between. The re-read happens inside the grant's own
		// transaction, and a link that is no longer live gets the same
		// 404 an unknown token gets (review C1-3).
		_, live, err := a.store.mintGrantViaLink(r.Context(), link.ID, p.ID)
		if err != nil {
			a.logger.Error("calls: mint grant", "err", err)
			a.ErrorPage(w, r, http.StatusInternalServerError, "")
			return
		}
		if !live {
			a.ErrorPage(w, r, http.StatusNotFound, "")
			return
		}
	}
	http.Redirect(w, r, "/m/"+m.Sqid+"/join", http.StatusSeeOther)
}

// holding is GET /m/{sqid}/join, authorized by standing or a live
// participation for this session (spec §2.5), the same row the room
// page uses.
func (a *app) holding(w http.ResponseWriter, r *http.Request) {
	m, p, st, ok := a.roomAccess(w, r)
	if !ok {
		return
	}
	// This session's own peer, if it already has one here — a second
	// tab open on the same meeting — points the person at the takeover
	// confirm page rather than a plain join that would collide with it.
	var openElsewhere bool
	if session, ok := a.sessionKey(r); ok {
		_, openElsewhere = a.hub.LiveForSession(m.Sqid, session)
	}
	title := a.store.title(m)
	render(w, "join", a.page(r, onMeeting("", title), map[string]any{
		"Sqid": m.Sqid, "Title": title, "Starts": a.fmtStart(m.StartsAt),
		"Name": p.Name, "Standing": st.String(), "IsMember": st == StandingMember,
		"Floor": !a.relayConfigured(), "OpenElsewhere": openElsewhere,
		// Not oficina-calls://join?url=…/m/{sqid} (until 2026-10-02): the
		// app has a session of its own, or none, and the meeting's
		// address told it nothing about who this is, so a guest — and
		// anyone whose default browser was not this one — could not get
		// in. The offer hands this browser's person over (appOffer).
		"AppHref": "/m/" + m.Sqid + "/app",
	}))
}

// Only app-constructed meeting URLs are promoted to the custom URL scheme.
func nativeJoinURL(meeting string) template.URL {
	return template.URL("oficina-calls://join?url=" + url.QueryEscape(meeting))
}