/**
 * Day detail panel: popover (desktop) or bottom sheet (mobile) on calendar cell tap.
 */

import { getCalendarEl, state } from "./dom.js";
import { t } from "./i18n.js";
import { escapeHtml } from "./utils.js";
import { buildContactLinksHtml } from "./contactHtml.js";
import { localDateString, dateKeyToDDMM } from "./dateUtils.js";
import { getDutyMarkerRows } from "./hints.js";

const BOTTOM_SHEET_BREAKPOINT_PX = 640;
const POPOVER_MARGIN = 12;

/** @type {HTMLElement|null} */
let panelEl = null;
/** @type {HTMLElement|null} */
let overlayEl = null;
/** @type {((e: MouseEvent) => void)|null} */
let popoverCloseHandler = null;
/** Scroll position saved when sheet opens (for restore on close). */
let sheetScrollY = 0;

/**
 * Parse JSON from data attribute (values are stored with " for safety).
 * @param {string} raw
 * @returns {object[]|string[]}
 */
function parseDataAttr(raw) {
  if (!raw) return [];
  try {
    const parsed = JSON.parse(raw);
    return Array.isArray(parsed) ? parsed : [];
  } catch (e) {
    return [];
  }
}

/**
 * Build HTML content for the day detail panel.
 * @param {string} dateKey - YYYY-MM-DD
 * @param {object[]} duties - Array of { event_type, full_name, start_at?, end_at? }
 * @param {string[]} eventSummaries - Calendar event summary strings
 * @returns {string}
 */
export function buildDayDetailContent(dateKey, duties, eventSummaries) {
  const lang = state.lang;
  const todayKey = localDateString(new Date());
  const ddmm = dateKeyToDDMM(dateKey);
  const title =
    dateKey === todayKey
      ? t(lang, "duty.today") + ", " + ddmm
      : ddmm;

  const dutyList = (duties || [])
    .filter((d) => d.event_type === "duty")
    .sort((a, b) => new Date(a.start_at || 0) - new Date(b.start_at || 0));
  const unavailableList = (duties || []).filter((d) => d.event_type === "unavailable");
  const vacationList = (duties || []).filter((d) => d.event_type === "vacation");
  const summaries = eventSummaries || [];

  const fromLabel = t(lang, "hint.from");
  const toLabel = t(lang, "hint.to");
  const nbsp = "\u00a0";

  let html =
    '<h2 id="dayDetailTitle" class="day-detail-title">' + escapeHtml(title) + "</h2>";
  html += '<div class="day-detail-sections">';

  if (dutyList.length > 0) {
    const hasTimes = dutyList.some(
      (it) => (it.start_at || it.end_at)
    );
    const rows = hasTimes
      ? getDutyMarkerRows(dutyList, dateKey, nbsp, fromLabel, toLabel)
      : dutyList.map((it) => ({
          timePrefix: "",
          fullName: it.full_name || "",
          phone: it.phone,
          username: it.username
        }));

    html +=
      '<section class="day-detail-section day-detail-section--duty">' +
      '<h3 class="day-detail-section-title">' +
      escapeHtml(t(lang, "event_type.duty")) +
      "</h3><ul class=" +
      '"day-detail-list">';
    rows.forEach((r, i) => {
      const duty = hasTimes ? dutyList[i] : null;
      const phone = r.phone != null ? r.phone : (duty && duty.phone);
      const username = r.username != null ? r.username : (duty && duty.username);
      const timeHtml = r.timePrefix ? escapeHtml(r.timePrefix) + " — " : "";
      const contactHtml = buildContactLinksHtml(lang, phone, username, {
        classPrefix: "day-detail-contact",
        showLabels: true,
        separator: " "
      });
      html +=
        "<li>" +
        (timeHtml ? '<span class="day-detail-time">' + timeHtml + "</span>" : "") +
        escapeHtml(r.fullName) +
        (contactHtml ? contactHtml : "") +
        "</li>";
    });
    html += "</ul></section>";
  }

  if (unavailableList.length > 0) {
    const uniqueUnavailable = [...new Set(unavailableList.map((d) => d.full_name || "").filter(Boolean))];
    html +=
      '<section class="day-detail-section day-detail-section--unavailable">' +
      '<h3 class="day-detail-section-title">' +
      escapeHtml(t(lang, "event_type.unavailable")) +
      "</h3><ul class=\"day-detail-list\">";
    uniqueUnavailable.forEach((name) => {
      html += "<li>" + escapeHtml(name) + "</li>";
    });
    html += "</ul></section>";
  }

  if (vacationList.length > 0) {
    const uniqueVacation = [...new Set(vacationList.map((d) => d.full_name || "").filter(Boolean))];
    html +=
      '<section class="day-detail-section day-detail-section--vacation">' +
      '<h3 class="day-detail-section-title">' +
      escapeHtml(t(lang, "event_type.vacation")) +
      "</h3><ul class=\"day-detail-list\">";
    uniqueVacation.forEach((name) => {
      html += "<li>" + escapeHtml(name) + "</li>";
    });
    html += "</ul></section>";
  }

  if (summaries.length > 0) {
    html +=
      '<section class="day-detail-section day-detail-section--events">' +
      '<h3 class="day-detail-section-title">' +
      escapeHtml(t(lang, "hint.events")) +
      "</h3><ul class=\"day-detail-list\">";
    summaries.forEach((s) => {
      html += "<li>" + escapeHtml(String(s)) + "</li>";
    });
    html += "</ul></section>";
  }

  html += "</div>";
  return html;
}

/**
 * Position panel as popover near cell rect; keep inside viewport.
 * @param {HTMLElement} panel
 * @param {DOMRect} cellRect
 */
function positionPopover(panel, cellRect) {
  const vw = document.documentElement.clientWidth;
  const vh = document.documentElement.clientHeight;
  const margin = POPOVER_MARGIN;
  panel.classList.remove("day-detail-panel--below");
  panel.style.left = "";
  panel.style.top = "";
  panel.style.right = "";
  panel.style.bottom = "";
  panel.hidden = false;
  requestAnimationFrame(() => {
    const panelRect = panel.getBoundingClientRect();
    let left = cellRect.left + cellRect.width / 2 - panelRect.width / 2;
    let top = cellRect.bottom + 8;
    /* day-detail-panel--below: panel is positioned above the cell (not enough space below). Used for optional styling (e.g. arrow). */
    if (top + panelRect.height > vh - margin) {
      top = cellRect.top - panelRect.height - 8;
      panel.classList.add("day-detail-panel--below");
    } else {
      panel.classList.remove("day-detail-panel--below");
    }
    if (left < margin) left = margin;
    if (left + panelRect.width > vw - margin) left = vw - panelRect.width - margin;
    panel.style.left = left + "px";
    panel.style.top = top + "px";
  });
}

/**
 * Show panel as bottom sheet (fixed at bottom).
 * Renders panel closed (translateY(100%)), then on next frame adds open/visible classes for animation.
 */
function showAsBottomSheet() {
  if (!panelEl || !overlayEl) return;
  overlayEl.classList.remove("day-detail-overlay--visible");
  panelEl.classList.remove("day-detail-panel--open");
  overlayEl.hidden = false;
  panelEl.classList.add("day-detail-panel--sheet");
  panelEl.style.left = "";
  panelEl.style.top = "";
  panelEl.style.right = "";
  panelEl.style.bottom = "0";
  panelEl.hidden = false;

  sheetScrollY = window.scrollY;
  document.body.classList.add("day-detail-sheet-open");
  document.body.style.top = "-" + sheetScrollY + "px";

  requestAnimationFrame(() => {
    requestAnimationFrame(() => {
      overlayEl.classList.add("day-detail-overlay--visible");
      panelEl.classList.add("day-detail-panel--open");
      const closeBtn = panelEl.querySelector(".day-detail-close");
      if (closeBtn) closeBtn.focus();
    });
  });
}

/**
 * Show panel as popover at cell position.
 * @param {DOMRect} cellRect
 */
function showAsPopover(cellRect) {
  if (!panelEl || !overlayEl) return;
  overlayEl.hidden = true;
  panelEl.classList.remove("day-detail-panel--sheet");
  positionPopover(panelEl, cellRect);
  if (popoverCloseHandler) document.removeEventListener("click", popoverCloseHandler);
  popoverCloseHandler = (e) => {
    const target = e.target instanceof Node ? e.target : null;
    if (!target || !panelEl) return;
    if (panelEl.contains(target)) return;
    const calendarEl = getCalendarEl();
    if (target instanceof HTMLElement && calendarEl && calendarEl.contains(target) && target.closest(".day")) return;
    hideDayDetail();
  };
  setTimeout(() => document.addEventListener("click", popoverCloseHandler), 0);
}

/** Timeout fallback (ms) if transitionend does not fire (e.g. prefers-reduced-motion). */
const SHEET_CLOSE_TIMEOUT_MS = 400;

/**
 * Hide panel and overlay. For bottom sheet: remove open classes, wait for transitionend (or timeout), then cleanup.
 */
export function hideDayDetail() {
  if (popoverCloseHandler) {
    document.removeEventListener("click", popoverCloseHandler);
    popoverCloseHandler = null;
  }
  const isSheet =
    panelEl &&
    overlayEl &&
    panelEl.classList.contains("day-detail-panel--sheet") &&
    document.body.classList.contains("day-detail-sheet-open");

  if (isSheet) {
    panelEl.classList.remove("day-detail-panel--open");
    overlayEl.classList.remove("day-detail-overlay--visible");

    const finishClose = () => {
      if (closeTimeoutId != null) clearTimeout(closeTimeoutId);
      panelEl.removeEventListener("transitionend", onTransitionEnd);
      document.body.classList.remove("day-detail-sheet-open");
      document.body.style.top = "";
      window.scrollTo(0, sheetScrollY);
      panelEl.classList.remove("day-detail-panel--sheet");
      panelEl.hidden = true;
      overlayEl.hidden = true;
    };

    let closeTimeoutId = setTimeout(finishClose, SHEET_CLOSE_TIMEOUT_MS);

    const onTransitionEnd = (e) => {
      if (e.target !== panelEl || e.propertyName !== "transform") return;
      finishClose();
    };
    panelEl.addEventListener("transitionend", onTransitionEnd);
    return;
  }

  if (document.body.classList.contains("day-detail-sheet-open")) {
    document.body.classList.remove("day-detail-sheet-open");
    document.body.style.top = "";
    window.scrollTo(0, sheetScrollY);
  }
  if (panelEl) panelEl.hidden = true;
  if (overlayEl) overlayEl.hidden = true;
}

/**
 * Open day detail for the given cell (reads data from data-* attributes).
 * @param {HTMLElement} cell - .day element
 */
function openDayDetail(cell) {
  const dateKey = cell.getAttribute("data-date");
  if (!dateKey) return;

  const dutiesRaw = cell.getAttribute("data-day-duties");
  const eventsRaw = cell.getAttribute("data-day-events");
  const duties = /** @type {object[]} */ (parseDataAttr(dutiesRaw || ""));
  const eventSummaries = /** @type {string[]} */ (parseDataAttr(eventsRaw || ""));

  if (duties.length === 0 && eventSummaries.length === 0) return;

  ensurePanelInDom();
  if (!panelEl) return;

  const contentHtml = buildDayDetailContent(dateKey, duties, eventSummaries);
  const body = panelEl.querySelector(".day-detail-body");
  if (body) body.innerHTML = contentHtml;

  const isNarrow = window.matchMedia("(max-width: " + BOTTOM_SHEET_BREAKPOINT_PX + "px)").matches;
  if (isNarrow) {
    showAsBottomSheet();
  } else {
    const rect = cell.getBoundingClientRect();
    showAsPopover(rect);
  }
}

/**
 * Ensure #dayDetailPanel and overlay exist in DOM.
 */
function ensurePanelInDom() {
  if (panelEl) return;
  overlayEl = document.getElementById("dayDetailOverlay");
  panelEl = document.getElementById("dayDetailPanel");
  if (!overlayEl) {
    overlayEl = document.createElement("div");
    overlayEl.id = "dayDetailOverlay";
    overlayEl.className = "day-detail-overlay";
    overlayEl.setAttribute("aria-hidden", "true");
    overlayEl.hidden = true;
    document.body.appendChild(overlayEl);
  }
  if (!panelEl) {
    panelEl = document.createElement("div");
    panelEl.id = "dayDetailPanel";
    panelEl.className = "day-detail-panel";
    panelEl.setAttribute("role", "dialog");
    panelEl.setAttribute("aria-modal", "true");
    panelEl.setAttribute("aria-labelledby", "dayDetailTitle");
    panelEl.hidden = true;

    const closeLabel = t(state.lang, "day_detail.close");
    panelEl.innerHTML =
      '<button type="button" class="day-detail-close" aria-label="' +
      escapeHtml(closeLabel) +
      '">×</button><div class="day-detail-body"></div>';

    const closeBtn = panelEl.querySelector(".day-detail-close");
    if (closeBtn) {
      closeBtn.addEventListener("click", hideDayDetail);
    }
    panelEl.addEventListener("keydown", (e) => {
      if (e.key === "Escape") hideDayDetail();
    });
    overlayEl.addEventListener("click", hideDayDetail);
    document.body.appendChild(panelEl);
  }
}

/**
 * Bind delegated click/keydown on calendar for .day cells.
 */
export function initDayDetail() {
  const calendarEl = getCalendarEl();
  if (!calendarEl) return;
  calendarEl.addEventListener("click", (e) => {
    const cell = /** @type {HTMLElement} */ (e.target instanceof HTMLElement ? e.target.closest(".day") : null);
    if (!cell) return;
    e.preventDefault();
    openDayDetail(cell);
  });
  calendarEl.addEventListener("keydown", (e) => {
    if (e.key !== "Enter" && e.key !== " ") return;
    const cell = /** @type {HTMLElement} */ (e.target instanceof HTMLElement ? e.target.closest(".day") : null);
    if (!cell) return;
    e.preventDefault();
    openDayDetail(cell);
  });
}