/* ==========================================================================
   librus-tui frontend - dashboard view
   ========================================================================== */

"use strict";

async function renderDashboard(token) {
  const [bootstrap, notifications, timetable, freedays] = await Promise.all([
    api("/api/bootstrap"),
    api("/api/notifications").catch(() => null),
    api("/api/timetable?week=0").catch(() => null),
    api("/api/freedays").catch(() => null),
  ]);

  if (token !== state.loadToken) return;

  applyUserChrome(bootstrap);

  const me = bootstrap.me || {};
  const school = bootstrap.school || {};
  const behaviour = bootstrap.behaviour;
  const lucky = bootstrap.luckyNumber;
  const notif = notifications || {};

  const now = new Date();
  const todayName = DAY_NAMES[now.getDay()];
  const todayIndex = (now.getDay() + 6) % 7; // Monday = 0
  const todayIso = isoDate(now);
  const week = (timetable && timetable.Timetable) || {};

  let dayName = todayName;
  let lessons = week[todayName] || [];
  let dayDate = (lessons[0] && lessons[0].Date) || todayIso;

  if (!lessons.length) {
    // Prefer the next day that still belongs to the current week.
    for (let offset = 1; offset < 7 - todayIndex; offset += 1) {
      const candidate = WEEK_ORDER[todayIndex + offset];
      const candidateLessons = week[candidate] || [];
      if (candidateLessons.length) {
        dayName = candidate;
        lessons = candidateLessons;
        dayDate = candidateLessons[0].Date || todayIso;
        break;
      }
    }
  }

  if (!lessons.length) {
    // Weekends: peek at next week so the panel is not empty.
    try {
      const nextWeek = await api("/api/timetable?week=1");
      if (token !== state.loadToken) return;
      const nextData = (nextWeek && nextWeek.Timetable) || {};
      const firstDay = WEEK_ORDER.find((day) => (nextData[day] || []).length);
      if (firstDay) {
        dayName = firstDay;
        lessons = nextData[firstDay];
        dayDate = (lessons[0] && lessons[0].Date) || todayIso;
      }
    } catch (error) {
      /* dashboard works without a preview */
    }
  }

  const isToday = dayDate === todayIso;
  const schoolFree = ((freedays && freedays.school) || [])
    .filter((item) => item && item.DateFrom)
    .slice()
    .sort((a, b) => (parseDate(a.DateFrom) || 0) - (parseDate(b.DateFrom) || 0));

  const upcomingFree = schoolFree
    .filter((item) => (daysUntil(item.DateFrom) ?? -1) >= 0)
    .slice(0, 4);

  const freeRows = upcomingFree.length
    ? upcomingFree
        .map(
          (item) => `
          <div class="freeday-line" title="${esc(fmtDate(item.DateFrom))} → ${esc(fmtDate(item.DateTo))}">
            <span class="name">${esc(item.Name || "free day")}</span>
            <span class="countdown ${countdownClass(item.DateFrom)}">${esc(countdownLabel(item.DateFrom))} · ${esc(fmtDateShort(item.DateFrom))}</span>
          </div>`
        )
        .join("")
    : `<div class="empty">no upcoming free days</div>`;

  const lessonsHtml = renderDashboardLessons(lessons, isToday);

  const html = `
    <div class="view-inner">
      <div class="dash-grid">
        <section class="panel span-2 identity-panel">
          <div class="panel-title">
            <span>student profile</span>
            <span class="title-note">${esc(me.Type || "synergia")}</span>
          </div>
          <div class="panel-body">
            <div class="identity-name">${esc(me.FirstName || "")} ${esc(me.LastName || "")}</div>
            <div class="identity-sub">
              <span class="class-chip">class ${esc(me.Class || "—")}</span>
              <span class="dim"> · tutor ${esc(personName(me.Tutor) || "—")}</span>
            </div>
            <dl class="kv">
              <dt>school</dt><dd>${esc(school.Name || "—")}</dd>
              <dt>address</dt><dd>${esc(schoolAddress(school))}</dd>
              <dt>year</dt><dd>${esc(fmtDate(me.SchoolYearStarts))} → ${esc(fmtDate(me.SchoolYearEnds))}</dd>
              <dt>semester</dt><dd>ends ${esc(fmtDate(me.SchoolYearMiddles))}</dd>
            </dl>
          </div>
        </section>

        <section class="panel">
          <div class="panel-title"><span>lucky number</span><span class="title-note">daily draw</span></div>
          <div class="lucky">
            <div class="lucky-number">${lucky === null || lucky === undefined ? "–" : esc(lucky)}</div>
            <div class="lucky-label">${lucky === null || lucky === undefined ? "not drawn yet" : "today's number"}</div>
          </div>
        </section>

        <section class="panel behaviour-panel">
          <div class="panel-title"><span>behaviour</span><span class="title-note">semester 1</span></div>
          <div class="behaviour">
            <div class="behaviour-grade">${behaviour ? esc(titleCase(behaviour.Grade)) : "—"}</div>
            <div class="behaviour-teacher">${behaviour ? esc(personName(behaviour.Teacher) || "—") : "no grade yet"}</div>
          </div>
        </section>

        <section class="panel counters-panel">
          <div class="panel-title">
            <span>counters</span>
            <span class="title-note">click to open a section</span>
          </div>
          <div class="stat-grid">
            <button class="stat" type="button" data-view="grades">
              <span class="stat-value">${notif.grades ?? "—"}</span>
              <span class="stat-label">grades</span>
            </button>
            <button class="stat" type="button" data-view="homework">
              <span class="stat-value">${notif.exams ?? "—"}</span>
              <span class="stat-label">homework</span>
            </button>
            <button class="stat warn" type="button" data-view="attendance">
              <span class="stat-value">${notif.absences ?? "—"}</span>
              <span class="stat-label">absences</span>
            </button>
            <button class="stat" type="button" data-view="freedays">
              <span class="stat-value">${notif.conferences ?? "—"}</span>
              <span class="stat-label">conferences</span>
            </button>
          </div>
        </section>

        <section class="panel span-2 today-panel">
          <div class="panel-title">
            <span>${isToday ? "today" : "next school day"} · ${esc(dayName)}</span>
            <span class="title-note">${esc(fmtDate(dayDate))}${isToday ? "" : " · coming up"}</span>
          </div>
          <div class="panel-body tight">${lessonsHtml}</div>
        </section>

        <section class="panel freedays-panel">
          <div class="panel-title">
            <span>upcoming breaks</span>
            <span class="title-note">${upcomingFree.length} ahead</span>
          </div>
          <div class="panel-body tight">${freeRows}</div>
        </section>
      </div>
    </div>
  `;

  $("#view").innerHTML = html;
}

function renderDashboardLessons(lessons, isToday) {
  if (!lessons || !lessons.length) {
    return `<div class="empty">no lessons</div>`;
  }

  const sorted = lessons
    .slice()
    .sort((a, b) => (timeToMinutes(a.HourFrom) ?? 9999) - (timeToMinutes(b.HourFrom) ?? 9999));

  const now = new Date();
  const nowMinutes = now.getHours() * 60 + now.getMinutes();
  let currentIndex = -1;
  let nextIndex = -1;

  if (isToday) {
    for (let index = 0; index < sorted.length; index += 1) {
      const lesson = sorted[index];
      const start = timeToMinutes(lesson.HourFrom);
      const end = timeToMinutes(lesson.HourTo);
      if (start !== null && end !== null && nowMinutes >= start && nowMinutes <= end) {
        currentIndex = index;
      } else if (nextIndex === -1 && start !== null && start > nowMinutes && !lesson.isCancelled) {
        nextIndex = index;
      }
    }
  }

  return `<div class="lesson-list">${sorted
    .map((lesson, index) => {
      const classes = ["lesson-line"];
      if (index === currentIndex) classes.push("now");
      if (index === nextIndex) classes.push("next");
      if (lesson.isCancelled) classes.push("cancelled");
      const marker = index === currentIndex ? ">" : index === nextIndex ? "»" : "·";
      const room = [lesson.Classroom, personName(lesson.Teacher)].filter(Boolean).join(" · ");
      return `
        <div class="${classes.join(" ")}" title="${esc(room)}">
          <span class="time">${esc(shortTime(lesson.HourFrom) || "—")}</span>
          <span class="marker">${marker}</span>
          <span class="subject">${esc(lesson.Subject || "lesson")}</span>
          <span class="room">${esc(lesson.Classroom || "")}${lesson.isCancelled ? " [cancelled]" : ""}</span>
        </div>`;
    })
    .join("")}</div>`;
}