/* ═══════════════════════════════════════════
   Phosphor Terminal — Window Manager (wm.js)
   ═══════════════════════════════════════════ */

const WM = (() => {
  "use strict";

  let topZ = 100;
  const state = new Map(); // wid → { el, hidden, maximized, savedStyle }
  let drag = null;
  let resize = null;

  /* ── Init ──────────────────────────────── */

  function init() {
    document.querySelectorAll(".window").forEach(register);
    setupIcons();
    document.addEventListener("mousemove", onMove);
    document.addEventListener("mouseup",   onUp);
    // Focus topmost visible window on load
    const visible = [...state.values()].filter(s => !s.hidden);
    if (visible.length) focusEl(visible[visible.length - 1].el);
  }

  /* ── Build and inject window chrome ────── */

  function buildChrome(win) {
    const title = win.dataset.title || win.dataset.wid || "";

    const bar = document.createElement("div");
    bar.className = "window-titlebar";
    const maxBtn = document.createElement("button");
    maxBtn.className = "win-btn maximize";
    maxBtn.title = "Full screen";
    maxBtn.textContent = "⤢";
    const titleSpan = document.createElement("span");
    titleSpan.className = "window-title";
    titleSpan.textContent = title;
    bar.appendChild(maxBtn);
    bar.appendChild(titleSpan);
    win.insertBefore(bar, win.firstChild);

    const footer = document.createElement("div");
    footer.className = "window-footer";
    const closeBtn = document.createElement("button");
    closeBtn.className = "win-btn close";
    closeBtn.title = "Close";
    closeBtn.textContent = "×";
    const spacer = document.createElement("div");
    spacer.className = "win-footer-spacer";
    const resizeHandle = document.createElement("div");
    resizeHandle.className = "win-resize";
    resizeHandle.title = "Drag to resize";
    resizeHandle.textContent = "◢";
    footer.appendChild(closeBtn);
    footer.appendChild(spacer);
    footer.appendChild(resizeHandle);
    win.appendChild(footer);
  }

  /* ── Register a window element ─────────── */

  function register(win) {
    const id = win.dataset.wid;
    if (!id || state.has(id)) return;

    buildChrome(win);

    const hidden = win.classList.contains("hidden");
    state.set(id, { el: win, hidden, maximized: false, savedStyle: null });

    // Draggable title bar
    const bar = win.querySelector(".window-titlebar");
    bar.addEventListener("mousedown", e => {
      if (e.button !== 0 || e.target.closest(".win-btn")) return;
      startDrag(e, win);
    });

    // Focus on any click inside window
    win.addEventListener("mousedown", () => {
      if (!state.get(id)?.hidden) focusEl(win);
    });

    // Window buttons
    const q = s => win.querySelector(s);
    const closeAction = win.dataset.close;
    q(".win-btn.close")   ?.addEventListener("click", () => closeAction === "back" ? history.back() : hide(id));
    q(".win-btn.maximize")?.addEventListener("click", () => toggleMax(id));

    // Resize handle
    q(".win-resize")?.addEventListener("mousedown", e => {
      if (e.button !== 0) return;
      e.preventDefault(); e.stopPropagation();
      const r = win.getBoundingClientRect();
      resize = { el: win, x0: e.clientX, y0: e.clientY, w0: r.width, h0: r.height };
    });
  }

  /* ── Focus ─────────────────────────────── */

  function focusEl(win) {
    document.querySelectorAll(".window.focused")
      .forEach(w => w.classList.remove("focused"));
    win.classList.add("focused");
    win.style.zIndex = ++topZ;
  }

  function focus(id) {
    const s = state.get(id);
    if (s && !s.hidden) focusEl(s.el);
  }

  /* ── Show / Hide ───────────────────────── */

  function show(id) {
    const s = state.get(id);
    if (!s) return;
    s.el.classList.remove("hidden");
    s.hidden = false;
    focusEl(s.el);
  }

  function hide(id) {
    const s = state.get(id);
    if (!s) return;
    s.el.classList.add("hidden");
    s.hidden = true;
  }

  function toggle(id) {
    const s = state.get(id);
    if (!s) return;
    if (s.hidden) {
      show(id);
    } else if (s.el.classList.contains("focused")) {
      hide(id);
    } else {
      focusEl(s.el);
    }
  }

  /* ── Maximize / Restore ────────────────── */

  function toggleMax(id) {
    const s = state.get(id);
    if (!s) return;
    const el  = s.el;
    const area = document.querySelector(".desktop-area");

    if (!s.maximized) {
      s.savedStyle = {
        top:    el.style.top,    left:   el.style.left,
        width:  el.style.width,  height: el.style.height,
        transform: el.style.transform,
      };
      el.style.transform = "none";
      el.style.top    = "0";
      el.style.left   = "0";
      el.style.width  = area.clientWidth  + "px";
      el.style.height = area.clientHeight + "px";
      s.maximized = true;
    } else {
      const sv = s.savedStyle;
      el.style.top    = sv.top;
      el.style.left   = sv.left;
      el.style.width  = sv.width;
      el.style.height = sv.height;
      el.style.transform = sv.transform;
      s.maximized = false;
    }
    focusEl(el);
  }

  /* ── Drag ──────────────────────────────── */

  function startDrag(e, win) {
    e.preventDefault();
    focusEl(win);

    // Freeze any CSS transform into explicit top/left so dragging is consistent
    const wr = win.getBoundingClientRect();
    const pr = win.offsetParent?.getBoundingClientRect() ?? { left: 0, top: 0 };
    const left0 = wr.left - pr.left;
    const top0  = wr.top  - pr.top;
    win.style.transform = "none";
    win.style.left = left0 + "px";
    win.style.top  = top0  + "px";

    drag = { el: win, x0: e.clientX, y0: e.clientY, left0, top0 };
    document.body.style.cursor = "move";
  }

  /* ── Mouse events ──────────────────────── */

  function onMove(e) {
    if (drag) {
      const dx = e.clientX - drag.x0;
      const dy = e.clientY - drag.y0;
      drag.el.style.left = (drag.left0 + dx) + "px";
      drag.el.style.top  = (drag.top0  + dy) + "px";
    }
    if (resize) {
      const dx = e.clientX - resize.x0;
      const dy = e.clientY - resize.y0;
      resize.el.style.width  = Math.max(280, resize.w0 + dx) + "px";
      resize.el.style.height = Math.max(140, resize.h0 + dy) + "px";
    }
  }

  function onUp() {
    drag   = null;
    resize = null;
    document.body.style.cursor = "";
  }

  /* ── Desktop icons ─────────────────────── */

  function setupIcons() {
    document.querySelectorAll(".desktop-icon[data-opens]").forEach(icon => {
      icon.addEventListener("click", () => {
        document.querySelectorAll(".desktop-icon.active")
          .forEach(i => i.classList.remove("active"));
        icon.classList.add("active");
        show(icon.dataset.opens);
      });
    });
  }

  /* ── Boot: hide icons for hidden windows ─ */

  document.addEventListener("DOMContentLoaded", init);

  return { show, hide, toggle, focus };
})();