package main

// A reminder on demand, without the operator's calendar: a second Betterbird, in a profile of its own
// under the account's runtime directory, with one local calendar file holding one event whose reminder
// is due a few seconds after the start. The running Betterbird, its profile, its accounts and its
// calendars are not touched: the second one starts with --no-remote, so it neither hands over to the
// first nor is handed to.
//
// The test profile gets the module's user.js too, so the reminder is drawn with the preferences the
// module declares. A theme or another preference of the operator's profile can be carried over by
// name (carry), within the same limits as betterbird_prefs: never a credential, never an account.
//
// It lives for at most ten minutes (the unit's RuntimeMaxSec), and stop ends it early and removes the
// profile. The reminder window is then found with xorg_windows (class Calendar, role AlarmWindow) and
// looked at with xorg_screenshot.

import (
	"fmt"
	"os"
	"path/filepath"
	"regexp"
	"strconv"
	"strings"
	"time"
)

// testDir is the test's profile and calendar, under the account's runtime directory.
func (m *Machine) testDir() string {
	return m.path(fmt.Sprintf("/run/user/%d/%s", m.UID, testUnit))
}

// carryName is a preference name the test may carry over from the operator's profile.
var carryName = regexp.MustCompile(`^[A-Za-z0-9_.\-]+$`)

// ReminderAnswer is what betterbird_reminder_test answers.
type ReminderAnswer struct {
	Unit     string   `json:"unit"`
	Profile  string   `json:"profile"`
	Event    string   `json:"event"`
	Due      string   `json:"reminder_due"`
	Carried  []string `json:"carried,omitempty"`
	Withheld []string `json:"withheld,omitempty"`
	Look     string   `json:"look"`
	Stopped  bool     `json:"stopped,omitempty"`
}

// ics is the test calendar: one event, its reminder `after` from now.
func ics(now time.Time, after time.Duration, stamp string) string {
	f := func(t time.Time) string { return t.UTC().Format("20060102T150405Z") }
	start := now.Add(after + 10*time.Minute)
	return strings.Join([]string{"BEGIN:VCALENDAR", "VERSION:2.0", "PRODID:-//novox mesh//betterbird reminder test//EN",
		"BEGIN:VEVENT", "UID:mesh-reminder-test-" + stamp + "@mesh", "DTSTAMP:" + f(now), "DTSTART:" + f(start),
		"DTEND:" + f(start.Add(30*time.Minute)), "SUMMARY:Mesh reminder test", "BEGIN:VALARM", "ACTION:DISPLAY",
		"DESCRIPTION:Mesh reminder test", "TRIGGER:-PT10M", "END:VALARM", "END:VEVENT", "END:VCALENDAR", ""}, "\r\n")
}

// testPrefs are the test profile's own preferences: its one calendar, and no first-run questions.
func testPrefs(calendar string) string {
	return strings.Join([]string{
		`user_pref("calendar.registry.meshtest.type", "ics");`,
		`user_pref("calendar.registry.meshtest.uri", "file://` + calendar + `");`,
		`user_pref("calendar.registry.meshtest.name", "Mesh reminder test");`,
		`user_pref("calendar.registry.meshtest.calendar-main-in-composite", true);`,
		`user_pref("calendar.registry.meshtest.suppressAlarms", false);`,
		`user_pref("calendar.list.sortOrder", "meshtest");`,
		`user_pref("mail.provider.suppress_dialog_on_startup", true);`,
		`user_pref("mail.shell.checkDefaultClient", false);`,
		`user_pref("datareporting.policy.dataSubmissionEnabled", false);`,
		`user_pref("toolkit.telemetry.reportingpolicy.firstRun", false);`,
		`user_pref("app.update.auto", false);`,
		`user_pref("mail.rights.version", 1);`,
		"",
	}, "\n")
}

// ReminderTest starts the test Betterbird, or with stop ends it and removes its profile.
func (m *Machine) ReminderTest(after time.Duration, carry []string, stop bool) (ReminderAnswer, error) {
	dir := m.testDir()
	a := ReminderAnswer{Unit: testUnit + ".service", Profile: strings.TrimPrefix(filepath.Join(dir, "profile"), m.Root),
		Look: "xorg_windows with class Calendar answers the reminder window (role AlarmWindow, its depth and map state); " +
			"xorg_screenshot with that window shows it as the screen does"}
	if stop {
		_ = m.cmd(5*time.Second, m.bus(), "systemctl", "--user", "stop", testUnit+".service")
		if err := os.RemoveAll(dir); err != nil {
			return a, err
		}
		a.Stopped, a.Look = true, ""
		return a, nil
	}
	s, err := m.session()
	if err != nil {
		return a, err
	}
	var carried []string
	if len(carry) > 0 {
		p, err := m.profile()
		if err != nil {
			return a, err
		}
		prefsJS, _ := readBounded(filepath.Join(p.path, "prefs.js"))
		have := readPrefs(prefsJS)
		for _, n := range carry {
			switch {
			case !carryName.MatchString(n):
				return a, fmt.Errorf("carry holds preference names, not %q", n)
			case withheld(n) != "":
				a.Withheld = append(a.Withheld, n+": "+withheld(n))
			case have[n] == "":
				a.Withheld = append(a.Withheld, n+": not set in the operator's profile")
			default:
				carried = append(carried, fmt.Sprintf("user_pref(%s, %s);", strconv.Quote(n), have[n]))
				a.Carried = append(a.Carried, n)
			}
		}
	}
	_ = m.cmd(5*time.Second, s.Env(), "systemctl", "--user", "stop", testUnit+".service")
	if err := os.RemoveAll(dir); err != nil {
		return a, err
	}
	if err := os.MkdirAll(filepath.Join(dir, "profile"), 0o700); err != nil {
		return a, err
	}
	now := m.Now()
	calendar := filepath.Join(dir, "test.ics")
	if err := os.WriteFile(calendar, []byte(ics(now, after, strconv.FormatInt(now.Unix(), 10))), 0o600); err != nil {
		return a, err
	}
	user := testPrefs(strings.TrimPrefix(calendar, m.Root))
	if mine, err := readBounded(m.home(declared)); err == nil && validUserJS(string(mine)) == nil {
		user = string(mine) + "\n" + user
	}
	user += strings.Join(carried, "\n") + "\n"
	if err := os.WriteFile(filepath.Join(dir, "profile", "user.js"), []byte(user), 0o600); err != nil {
		return a, err
	}
	// The unit removes the profile when it ends, however it ends: at its 10 minutes, on stop, or when the
	// test Betterbird is closed.
	call := []string{"--user", "--collect", "--quiet", "--unit=" + testUnit, "-p", "RuntimeMaxSec=600",
		"-p", "ExecStopPost=/usr/bin/rm -rf " + strings.TrimPrefix(dir, m.Root), "--setenv=MOZ_NO_REMOTE=1"}
	for _, kv := range [][2]string{{"DISPLAY", s.Display}, {"XAUTHORITY", s.XAuthority}} {
		if kv[1] != "" {
			call = append(call, "--setenv="+kv[0]+"="+kv[1])
		}
	}
	call = append(call, "--", startBin, "--no-remote", "--profile", strings.TrimPrefix(filepath.Join(dir, "profile"), m.Root))
	if err := failed(m.cmd(8*time.Second, s.Env(), "systemd-run", call...), "systemd-run", call...); err != nil {
		return a, err
	}
	a.Event = "Mesh reminder test, in a calendar file of the test profile only"
	a.Due = now.Add(after).UTC().Format(time.RFC3339)
	return a, nil
}