export type KeymapScope = "global" | "viewport" | "outliner" | "timeline" | "graph";

export interface KeymapActionDefinition {
  id: string;
  label: string;
  scope: KeymapScope;
  defaultChord: string;
  description?: string;
}

export const KEYMAP_ACTIONS: KeymapActionDefinition[] = [
  { id: "file.open", label: "打开 .blend", scope: "global", defaultChord: "Ctrl+O" },
  { id: "file.save", label: "保存到 OPFS", scope: "global", defaultChord: "Ctrl+S" },
  { id: "file.saveAs", label: "另存为（OPFS）", scope: "global", defaultChord: "Ctrl+Shift+S" },
  { id: "edit.undo", label: "撤销", scope: "global", defaultChord: "Ctrl+Z" },
  { id: "edit.redo", label: "重做", scope: "global", defaultChord: "Ctrl+Y" },
  { id: "edit.operatorSearch", label: "操作搜索", scope: "global", defaultChord: "F3" },
  { id: "edit.rename", label: "重命名活动项", scope: "global", defaultChord: "F2" },
  { id: "object.delete", label: "删除对象", scope: "viewport", defaultChord: "Delete" },
  { id: "object.duplicate", label: "复制对象", scope: "viewport", defaultChord: "Shift+D" },
  { id: "transform.translate", label: "移动", scope: "viewport", defaultChord: "G" },
  { id: "transform.rotate", label: "旋转", scope: "viewport", defaultChord: "R" },
  { id: "transform.scale", label: "缩放", scope: "viewport", defaultChord: "S" },
  { id: "view.camera", label: "相机视图（切换）", scope: "viewport", defaultChord: "Numpad0" },
  { id: "view.cameraToView", label: "对齐相机到视图", scope: "viewport", defaultChord: "Ctrl+Alt+Numpad0" },
  { id: "view.cameraLock", label: "锁定相机到视图（Camera to View）", scope: "viewport", defaultChord: "" },
  { id: "view.frameAll", label: "显示全部", scope: "viewport", defaultChord: "Home" },
  { id: "view.frameSelected", label: "框显所选", scope: "viewport", defaultChord: "NumpadDecimal" },
];

const ACTION_BY_ID = new Map(KEYMAP_ACTIONS.map((action) => [action.id, action]));
const RESERVED = new Set(["Meta+W", "Meta+T", "Meta+N", "Meta+Q", "Ctrl+W", "Ctrl+T", "Ctrl+N", "Alt+F4"]);

export function actionDefinition(id: string): KeymapActionDefinition | undefined {
  return ACTION_BY_ID.get(id);
}

export function chordFromEvent(event: Pick<KeyboardEvent, "key" | "code" | "ctrlKey" | "altKey" | "shiftKey" | "metaKey">): string {
  const parts: string[] = [];
  if (event.ctrlKey) parts.push("Ctrl");
  if (event.altKey) parts.push("Alt");
  if (event.shiftKey) parts.push("Shift");
  if (event.metaKey) parts.push("Meta");
  let key = event.key;
  if (event.code.startsWith("Numpad") && event.code !== "NumpadEnter") key = event.code;
  else if (key === " " || key === "Spacebar") key = "Space";
  else if (key.length === 1) key = key.toUpperCase();
  if (!["Control", "Alt", "Shift", "Meta"].includes(key)) parts.push(key);
  return parts.join("+");
}

export function normalizeChord(chord: string): string {
  const parts = chord.split("+").map((part) => part.trim()).filter(Boolean);
  if (parts.length === 0) return "";
  const modifiers = new Set(parts.filter((part) => ["Ctrl", "Alt", "Shift", "Meta"].includes(part)));
  const keys = parts.filter((part) => !["Ctrl", "Alt", "Shift", "Meta"].includes(part));
  if (keys.length !== 1) return chord.trim();
  const ordered = ["Ctrl", "Alt", "Shift", "Meta"].filter((modifier) => modifiers.has(modifier));
  let key = keys[0];
  if (key.length === 1) key = key.toUpperCase();
  if (key === " ") key = "Space";
  return [...ordered, key].join("+");
}

export function effectiveBindings(overrides: Record<string, string>): Record<string, string> {
  const bindings: Record<string, string> = {};
  for (const action of KEYMAP_ACTIONS) {
    const override = overrides[action.id];
    bindings[action.id] = normalizeChord(typeof override === "string" ? override : action.defaultChord);
  }
  return bindings;
}

export function findKeymapConflicts(bindings: Record<string, string>): Array<{ chord: string; actions: string[] }> {
  const byChord = new Map<string, string[]>();
  for (const action of KEYMAP_ACTIONS) {
    const chord = normalizeChord(bindings[action.id] ?? action.defaultChord);
    if (!chord) continue;
    const list = byChord.get(chord) ?? [];
    list.push(action.id);
    byChord.set(chord, list);
  }
  return [...byChord.entries()].filter(([, actions]) => actions.length > 1).map(([chord, actions]) => ({ chord, actions }));
}

export function resolveKeymapAction(event: KeyboardEvent, bindings: Record<string, string>, scope: KeymapScope): KeymapActionDefinition | null {
  const chord = chordFromEvent(event);
  for (const action of KEYMAP_ACTIONS) {
    if (action.scope !== scope && action.scope !== "global") continue;
    if (normalizeChord(bindings[action.id] ?? action.defaultChord) === chord) return action;
  }
  return null;
}

export function validateKeymapBinding(id: string, chord: string, bindings: Record<string, string>): { ok: boolean; reason?: string } {
  const action = ACTION_BY_ID.get(id);
  if (!action) return { ok: false, reason: "未知操作" };
  const normalized = normalizeChord(chord);
  if (!normalized) return { ok: true };
  if (RESERVED.has(normalized)) return { ok: false, reason: `${normalized} 被浏览器保留` };
  if (action.defaultChord && normalized === normalizeChord(action.defaultChord)) return { ok: true };
  const conflict = KEYMAP_ACTIONS.find((candidate) => candidate.id !== id &&
    ["global", action.scope].includes(candidate.scope) &&
    normalizeChord(bindings[candidate.id] ?? candidate.defaultChord) === normalized);
  return conflict ? { ok: false, reason: `与“${conflict.label}”冲突` } : { ok: true };
}

export function describeChord(chord: string): string {
  return chord.split("+").map((part) => part === "Ctrl" ? "Ctrl" : part === "Alt" ? "Alt" : part === "Shift" ? "Shift" : part === "Meta" ? "Meta" : part).join(" + ");
}