import {
  getDockLeafLayouts,
  getDockResizeTargets,
  simulateDrop,
  type DockGeometryOptions,
  type DropTarget,
  type FloatingRect,
  type FloatingResizeCorner,
  type LayoutBounds,
} from "../../../plugins/pane-manager";
import {
  normalizeWindowEditFocus,
  pathKey,
  type WindowEditDockMovePosition,
  type WindowEditState,
} from "./mode";

export interface WindowEditDockMovePreview {
  targetId: string;
  position: WindowEditDockMovePosition;
  rect: LayoutBounds;
}

function dockMovePositionLabel(position: WindowEditDockMovePosition): string {
  switch (position) {
    case "left":
      return "left";
    case "right":
      return "right";
    case "above":
      return "above";
    case "below":
      return "below";
  }
}

function dropPositionFromDockMovePosition(position: WindowEditDockMovePosition): Extract<DropTarget, { kind: "leaf" }>["position"] {
  return position === "above" ? "top" : position === "below" ? "bottom" : position;
}

function leafDropTarget(targetId: string, position: WindowEditDockMovePosition): DropTarget {
  return {
    kind: "leaf",
    targetId,
    position: dropPositionFromDockMovePosition(position),
  };
}

function windowEditLabel(state: WindowEditState, bounds: LayoutBounds, dockGeometryOptions: DockGeometryOptions): string {
  const focus = normalizeWindowEditFocus(state.focus, state.previewLayout, state.paneId, state.mode, bounds, dockGeometryOptions);
  if (state.mode === "move") return "WINDOW MOVE";
  if (focus.kind === "floating-resize") return `WINDOW RESIZE ${focus.corner}`;
  if (focus.kind !== "dock-resize") return "WINDOW RESIZE no handles";
  const targets = getDockResizeTargets(state.previewLayout, state.paneId, bounds, dockGeometryOptions);
  const index = targets.findIndex((target) => pathKey(target.path) === focus.pathKey);
  return `WINDOW RESIZE divider ${Math.max(1, index + 1)}/${Math.max(1, targets.length)}`;
}

export function windowEditStatusLine(
  state: WindowEditState,
  title: string,
  bounds: LayoutBounds,
  dockGeometryOptions: DockGeometryOptions,
  targetTitle?: string,
): string {
  const target = state.mode === "move" && state.focus.kind === "dock-move" && targetTitle
    ? ` -> ${targetTitle} ${dockMovePositionLabel(state.focus.position)}`
    : "";
  const notice = state.notice ? ` · ${state.notice}` : "";
  return `${windowEditLabel(state, bounds, dockGeometryOptions)}${notice} · ${title}${target}`;
}

/**
 * The keys window mode answers to, most needed first: how to leave comes
 * before how to move, so a narrow banner or panel that cuts the list short
 * still says it. Arrows stand for hjkl too, and Tab for w where they match.
 */
export function windowEditHelpItems(state: WindowEditState, pending: boolean): string[] {
  const leave = pending ? ["Enter apply", "Esc cancel"] : ["Esc exit"];
  const snap = ["1-4 quarter", "5-8 half"];
  if (state.mode === "move") {
    if (state.focus.kind === "dock-move") {
      return [...leave, "arrows side", "Tab target", "m window", "d float", "r resize", ...snap];
    }
    const floating = state.previewLayout.floating.some((entry) => entry.instanceId === state.paneId);
    return floating
      ? [...leave, "arrows move", "Shift fast", "Tab window", "d dock", "r resize", ...snap]
      : [...leave, "arrows target", "Tab window", "d float", "r resize", ...snap];
  }
  if (state.focus.kind === "floating-resize") {
    return [...leave, "arrows resize", "Shift fast", "Tab corner", "w window", "m move"];
  }
  return [...leave, "arrows divider", "Shift fast", "Tab divider", "w window", "m move"];
}

export function windowEditHelpText(state: WindowEditState, pending: boolean): string {
  return windowEditHelpItems(state, pending).join("  ");
}

export function resolveWindowEditDockMovePreview(
  state: WindowEditState | null,
  bounds: LayoutBounds,
  dockGeometryOptions: DockGeometryOptions,
): WindowEditDockMovePreview | null {
  if (!state || state.mode !== "move" || state.focus.kind !== "dock-move") return null;
  const focus = state.focus;
  const leaves = getDockLeafLayouts(state.previewLayout, bounds, dockGeometryOptions);
  const selectedDocked = leaves.some((leaf) => leaf.instanceId === state.paneId);
  const targetDocked = leaves.some((leaf) => leaf.instanceId === focus.targetId && leaf.instanceId !== state.paneId);
  if (!selectedDocked || !targetDocked) return null;

  const simulation = simulateDrop(
    state.previewLayout,
    state.paneId,
    leafDropTarget(focus.targetId, focus.position),
    bounds,
    dockGeometryOptions,
  );
  if (!simulation.previewRect) return null;
  return {
    targetId: focus.targetId,
    position: focus.position,
    rect: simulation.previewRect,
  };
}

export function getFloatingResizeCornerPosition(rect: FloatingRect, corner: FloatingResizeCorner): { x: number; y: number; marker: string } {
  switch (corner) {
    case "top-left":
      return { x: rect.x, y: rect.y, marker: "◤" };
    case "top-right":
      return { x: rect.x + rect.width - 1, y: rect.y, marker: "◥" };
    case "bottom-left":
      return { x: rect.x, y: rect.y + rect.height - 1, marker: "◣" };
    case "bottom-right":
      return { x: rect.x + rect.width - 1, y: rect.y + rect.height - 1, marker: "◢" };
  }
}