export type Field<T> = {
  kind: string;
  defaultValue?: T;
  default(value: T): Field<T>;
};

export type TableDefinition = {
  kind: "table";
  fields: Record<string, Field<unknown>>;
};

export type AuthContext = {
  userId: string;
  displayName: string;
  provider: "guest" | "google";
  isGuest: boolean;
  isAuthenticated: boolean;
  email?: string;
  emailVerified?: boolean;
  picture?: string;
};

export type LogContext = {
  info(message: string, data?: unknown): void;
  warn(message: string, data?: unknown): void;
  error(message: string, data?: unknown): void;
};

export type QueryBuilder<T> = {
  where(field: keyof T & string, value: unknown): QueryBuilder<T>;
  orderBy(field: keyof T & string, direction?: "asc" | "desc"): QueryBuilder<T>;
  limit(count: number): QueryBuilder<T>;
  all(): Array<T & { id: string; createdAt: string; updatedAt: string }>;
};

export type TableApi<T> = QueryBuilder<T> & {
  get(id: string): (T & { id: string; createdAt: string; updatedAt: string }) | null;
  insert(value: T): T & { id: string; createdAt: string; updatedAt: string };
  update(id: string, patch: Partial<T>): void;
  delete(id: string): void;
};

export type DbContext = Record<string, TableApi<Record<string, unknown>>>;

export type ServerContext = {
  auth: AuthContext;
  db: DbContext;
  env: Record<string, string | undefined>;
  log: LogContext;
};

export type EndpointRoute = {
  method: "GET" | "POST" | "PUT" | "PATCH" | "DELETE" | "OPTIONS" | "HEAD" | (string & {});
  path: `/${string}`;
};

export type EndpointHeaders = {
  get(name: string): string | null;
  has(name: string): boolean;
  entries(): IterableIterator<[string, string]>;
};

export type EndpointRequest = {
  method: string;
  path: string;
  url: string;
  headers: EndpointHeaders;
  query: URLSearchParams;
  text(): Promise<string>;
  json<T = unknown>(): Promise<T>;
  bytes(): Promise<Uint8Array>;
};

export type EndpointResponse = {
  kind: "response";
  status: number;
  headers?: Record<string, string>;
  body?: string | Uint8Array | ArrayBuffer;
};

export type EndpointResponseOptions = {
  status?: number;
  headers?: Record<string, string>;
};

export type EndpointDefinition<TResult = EndpointResponse | string | unknown | void> = {
  kind: "endpoint";
  method: string;
  path: string;
  handler: (ctx: ServerContext, req: EndpointRequest) => TResult | Promise<TResult>;
};

export function capsule<T>(definition: T): T;
export function query<T>(handler: (ctx: ServerContext) => T): (ctx: ServerContext) => T;
export function mutation<TArgs extends unknown[], TResult>(
  handler: (ctx: ServerContext, ...args: TArgs) => TResult
): (ctx: ServerContext, ...args: TArgs) => TResult;
export function endpoint<TResult>(
  route: EndpointRoute,
  handler: (ctx: ServerContext, req: EndpointRequest) => TResult | Promise<TResult>
): EndpointDefinition<TResult>;
export function json(value: unknown, options?: EndpointResponseOptions): EndpointResponse;
export function text(value: unknown, options?: EndpointResponseOptions): EndpointResponse;
export function empty(options?: EndpointResponseOptions): EndpointResponse;
export function redirect(url: string, options?: EndpointResponseOptions): EndpointResponse;
export function table(fields: Record<string, Field<unknown>>): TableDefinition;
export function string(): Field<string>;
export function boolean(): Field<boolean>;