// Retained-worktrees view (#84): every worktree the daemon is holding that no
// session uses, listed from `GET /api/worktrees` with a reclaim action.
//
// Wording is shared with the CLI (`maestro worktrees list`) and the TUI
// overlay: same reason labels, same in-the-way phrasing via
// `formatInTheWay` (the mirror of `InTheWay`'s Display impl). Reclaim reads
// as what it is — destructive — naming what will be lost before it happens
// and saying out loud that the branch survives (docs/WORKTREES.md).

import { escapeHtml } from "./html.js";
import {
  abbreviateCwd,
  abbreviateFolderName,
  formatInTheWay,
  reasonLabel,
  type RetainedWorktree,
  type Uuid,
} from "./types.js";

export interface WorktreesDeps {
  /** `GET /api/worktrees`. */
  load(): Promise<RetainedWorktree[]>;
  /** `DELETE /api/worktrees/:id`. */
  reclaim(id: Uuid): Promise<void>;
  /** The daemon's home dir, for `~` abbreviation of paths. */
  homeDir(): string | undefined;
}

export interface WorktreesViewHandle {
  el: HTMLElement;
  /** Re-fetch the store and re-render. Safe to call repeatedly. */
  refresh(): Promise<void>;
  dispose(): void;
}

/** Oldest-retained first, matching `maestro worktrees list`'s ordering. */
function sorted(items: RetainedWorktree[]): RetainedWorktree[] {
  return [...items].sort(
    (a, b) => Date.parse(a.retained_at) - Date.parse(b.retained_at),
  );
}

export function createWorktreesView(deps: WorktreesDeps): WorktreesViewHandle {
  const el = document.createElement("section");
  el.className = "worktrees";
  el.innerHTML = `
    <header class="wt-head">
      <h2 class="wt-title">retained worktrees</h2>
      <p class="wt-sub">
        Kept when a session ended with unsaved work. Reclaiming removes the
        directory only; branches are never deleted.
      </p>
    </header>
    <div class="wt-list"></div>
    <div class="wt-confirm" role="alertdialog" aria-modal="true" hidden></div>
  `;
  const listHost = el.querySelector<HTMLElement>(".wt-list")!;
  const confirmEl = el.querySelector<HTMLElement>(".wt-confirm")!;

  let pendingId: string | null = null;

  const render = (items: RetainedWorktree[]) => {
    listHost.replaceChildren();
    if (items.length === 0) {
      // A drained store is the normal state — say so plainly, not like
      // something went wrong.
      const empty = document.createElement("div");
      empty.className = "empty";
      empty.innerHTML = `
        <div class="empty-glyph" aria-hidden="true">⌂</div>
        <div class="empty-title">no retained worktrees</div>
        <p class="empty-hint">Nothing is being held. Worktrees kept after a force-kill or an unsaved exit show up here.</p>`;
      listHost.appendChild(empty);
      return;
    }
    const home = deps.homeDir();
    for (const w of sorted(items)) {
      listHost.appendChild(renderRow(w, home));
    }
  };

  const renderRow = (w: RetainedWorktree, home: string | undefined): HTMLElement => {
    const row = document.createElement("div");
    row.className = "wt-row";
    const clear = formatInTheWay(w.in_the_way ?? {}) === "no unsaved work";
    row.innerHTML = `
      <span class="wt-branch">${escapeHtml(w.branch)}</span>
      <span class="wt-path" title="${escapeHtml(w.path)}">${abbreviateFolderName(abbreviateCwd(w.path, home))}</span>
      <span class="wt-reason">${escapeHtml(reasonLabel(w.reason))}</span>
      <span class="wt-way"${clear ? ' data-clear="true"' : ""}>${escapeHtml(formatInTheWay(w.in_the_way ?? {}))}</span>
      <button class="btn wt-reclaim-btn" type="button">Reclaim</button>
    `;
    row.querySelector(".wt-reclaim-btn")!.addEventListener("click", () => {
      showConfirm(w);
    });
    return row;
  };

  const showConfirm = (w: RetainedWorktree) => {
    pendingId = w.id;
    // Mirrors the TUI's ReclaimConfirm line for line: what goes away, what is
    // in the way right now, and that the branch survives reclaim.
    confirmEl.innerHTML = `
      <div class="wt-confirm-panel">
        <p class="wt-confirm-q">Reclaim worktree ${escapeHtml(w.branch)}?</p>
        <p class="wt-confirm-way">Currently in the way: ${escapeHtml(formatInTheWay(w.in_the_way ?? {}))}</p>
        <p class="wt-confirm-note">The directory is removed; the branch is never deleted.</p>
        <div class="wt-confirm-actions">
          <button class="btn btn-danger wt-confirm-go" type="button">Reclaim</button>
          <button class="btn btn-ghost wt-confirm-cancel" type="button">Cancel</button>
        </div>
      </div>`;
    confirmEl.hidden = false;
    confirmEl.querySelector<HTMLButtonElement>(".wt-confirm-go")!.focus();
  };

  const hideConfirm = () => {
    pendingId = null;
    confirmEl.hidden = true;
    confirmEl.replaceChildren();
  };

  confirmEl.addEventListener("click", async (e) => {
    const target = e.target as HTMLElement;
    if (target.closest(".wt-confirm-cancel")) {
      hideConfirm();
      return;
    }
    if (!target.closest(".wt-confirm-go") || !pendingId) return;
    const id = pendingId;
    hideConfirm();
    try {
      await deps.reclaim(id);
    } catch (err) {
      alert(`Failed to reclaim: ${(err as Error).message}`);
    }
    await refresh();
  });

  const onKey = (e: KeyboardEvent) => {
    if (e.key === "Escape" && !confirmEl.hidden) hideConfirm();
  };
  document.addEventListener("keydown", onKey);

  const refresh = async () => {
    try {
      render(await deps.load());
    } catch (err) {
      listHost.replaceChildren();
      const fail = document.createElement("div");
      fail.className = "empty";
      fail.innerHTML = `<div class="empty-title">Couldn't load retained worktrees</div><p class="empty-hint"></p>`;
      fail.querySelector(".empty-hint")!.textContent = (err as Error).message;
      listHost.appendChild(fail);
    }
  };

  return {
    el,
    refresh,
    dispose() {
      document.removeEventListener("keydown", onKey);
      el.remove();
    },
  };
}