/**
 * The two kill prompts (#81, #160).
 *
 * A kill is destructive and unattended agents live in these sessions, so both
 * clients ask before one goes through — the TUI's `KillConfirm`, and
 * `openKillConfirmDialog` here (#160). Where the session's worktree still
 * holds uncommitted or unpushed work, the confirmation says so up front, the
 * same way the TUI's does.
 *
 * The daemon decides the rest: it refuses a kill over such a worktree, and
 * that refusal needs an answer the confirmation cannot give — a forced kill.
 * `openForceKillDialog` is that second prompt. A kill the daemon accepts never
 * reaches it.
 */
import { formatInTheWay, type InTheWay } from "./types.js";

/** What both prompts need: a target to name and a button that acts on it. */
interface KillDialogSpec {
  /** Session name, as the sidebar shows it. */
  name: string;
  /** Sentence under the title. */
  body: string;
  /** Label on the acting button. */
  confirmLabel: string;
  /** Extra class on the acting button, so tests and styles can find it. */
  confirmClass: string;
  /** Run it. A rejection is rendered in the dialog, which stays open so the
   *  press can be retried. */
  onConfirm: () => Promise<void>;
}

export interface KillConfirmPrompt {
  name: string;
  /** What the card last saw in the way, when anything was. Shown before the
   *  attempt, so "this will be refused" is not a surprise. */
  blockers: InTheWay | null;
  /** Run the plain kill. Opening a further dialog from here is allowed: the
   *  confirmation only closes itself if it is still the one on screen. */
  onKill: () => Promise<void>;
}

export interface ForceKillPrompt {
  /** Session name, as the sidebar shows it. */
  name: string;
  /** What the daemon reported in the way, when it reported anything. */
  blockers: InTheWay | null;
  /** Message from the daemon's refusal, shown when there is no breakdown. */
  reason: string;
  /** Run the forced kill. A rejection is rendered in the dialog, which stays
   *  open so the override can be retried. */
  onForce: () => Promise<void>;
}

let open: { el: HTMLElement; onKeydown: (ev: KeyboardEvent) => void } | null = null;

export function closeForceKillDialog(): void {
  if (!open) return;
  window.removeEventListener("keydown", open.onKeydown, true);
  open.el.remove();
  open = null;
}

/** Mount one of the prompts. Opening while one is up replaces it, so the
 *  confirmation and a refusal that follows it can never stack. */
function mount(p: KillDialogSpec): HTMLElement {
  closeForceKillDialog();

  const el = document.createElement("div");
  el.className = "kill-dialog";
  el.setAttribute("role", "dialog");
  el.setAttribute("aria-modal", "true");
  el.setAttribute("aria-label", `Kill ${p.name}`);

  const panel = document.createElement("div");
  panel.className = "kill-dialog-panel";

  const title = document.createElement("h2");
  title.className = "kill-dialog-title";
  title.textContent = `Kill "${p.name}"?`;

  const body = document.createElement("p");
  body.className = "kill-dialog-body";
  body.textContent = p.body;

  const error = document.createElement("p");
  error.className = "kill-dialog-error";
  error.hidden = true;

  const actions = document.createElement("div");
  actions.className = "kill-dialog-actions";
  const cancel = document.createElement("button");
  cancel.type = "button";
  cancel.className = "btn btn-ghost kill-dialog-cancel";
  cancel.textContent = "Cancel";
  cancel.addEventListener("click", closeForceKillDialog);
  const confirm = document.createElement("button");
  confirm.type = "button";
  confirm.className = `btn btn-danger ${p.confirmClass}`;
  confirm.textContent = p.confirmLabel;
  confirm.addEventListener("click", () => {
    confirm.disabled = true;
    void p
      .onConfirm()
      .then(() => {
        // A handler that opened the refusal prompt has already replaced this
        // dialog; closing here would take that one down with it.
        if (open?.el === el) closeForceKillDialog();
      })
      .catch((e: unknown) => {
        if (open?.el !== el) return;
        confirm.disabled = false;
        error.hidden = false;
        error.textContent = `Failed to kill: ${(e as Error).message}`;
      });
  });
  actions.append(cancel, confirm);

  panel.append(title, body, error, actions);

  // A press on the scrim cancels; one inside the panel is left alone.
  el.addEventListener("click", (ev) => {
    if (!panel.contains(ev.target as Node)) closeForceKillDialog();
  });
  el.appendChild(panel);
  document.body.appendChild(el);

  const onKeydown = (ev: KeyboardEvent): void => {
    if (ev.key !== "Escape") return;
    ev.preventDefault();
    ev.stopPropagation();
    closeForceKillDialog();
  };
  window.addEventListener("keydown", onKeydown, true);
  open = { el, onKeydown };
  // Cancel takes the focus in both prompts: a kill is never one keystroke
  // away from whatever asked for the dialog.
  cancel.focus();
  return el;
}

/** Ask before a kill the daemon has not seen yet (#160). */
export function openKillConfirmDialog(p: KillConfirmPrompt): HTMLElement {
  return mount({
    name: p.name,
    body: p.blockers
      ? `Its worktree still has ${formatInTheWay(p.blockers)}. The kill will be refused unless it is forced.`
      : "The session and everything running in it go away. Its worktree stays on disk.",
    confirmLabel: "Kill",
    confirmClass: "kill-dialog-kill",
    onConfirm: p.onKill,
  });
}

/** Offer the override after the daemon refuses a guarded kill (#81). */
export function openForceKillDialog(p: ForceKillPrompt): HTMLElement {
  return mount({
    name: p.name,
    body: p.blockers
      ? `Its worktree still has ${formatInTheWay(p.blockers)}. Forcing the kill removes the session and leaves the worktree on disk.`
      : `${p.reason} Forcing the kill removes the session and leaves the worktree on disk.`,
    confirmLabel: "Force kill",
    confirmClass: "kill-dialog-force",
    onConfirm: p.onForce,
  });
}