import {
  parseProjectStateSnapshot,
  type ProjectStateSnapshot,
} from "./project-state-snapshot.model.js";
import type { SerializedProjectCommand } from "./project-command.model.js";

export const projectStateRestoreCommandType = "project.restore-state";
export const projectStateRestoreCommandSchemaVersion = 1 as const;

export interface ProjectStateRestoreCommandPayload {
  expectedStateSha256: string;
  targetState: ProjectStateSnapshot;
}

export type ProjectStateRestoreCommand = SerializedProjectCommand<
  ProjectStateRestoreCommandPayload
> & {
  schemaVersion: typeof projectStateRestoreCommandSchemaVersion;
  type: typeof projectStateRestoreCommandType;
};

export function createProjectStateRestoreCommand(
  expectedStateSha256: string,
  targetState: ProjectStateSnapshot
): ProjectStateRestoreCommand {
  const command: ProjectStateRestoreCommand = {
    schemaVersion: projectStateRestoreCommandSchemaVersion,
    type: projectStateRestoreCommandType,
    payload: {
      expectedStateSha256,
      targetState: parseProjectStateSnapshot(targetState),
    },
  };
  assertProjectStateRestoreCommand(command);
  return command;
}

export function assertProjectStateRestoreCommand(
  value: unknown
): asserts value is ProjectStateRestoreCommand {
  if (!value || typeof value !== "object") {
    throw new Error("Project state restore command must be an object.");
  }
  const command = value as Partial<ProjectStateRestoreCommand>;
  if (
    command.type !== projectStateRestoreCommandType ||
    command.schemaVersion !== projectStateRestoreCommandSchemaVersion
  ) {
    throw new Error("Unsupported project state restore command.");
  }
  if (!command.payload || typeof command.payload !== "object") {
    throw new Error("Project state restore payload is required.");
  }
  const payload = command.payload as Partial<ProjectStateRestoreCommandPayload>;
  if (
    typeof payload.expectedStateSha256 !== "string" ||
    !/^[a-f0-9]{64}$/.test(payload.expectedStateSha256)
  ) {
    throw new Error("Expected project state checksum is invalid.");
  }
  parseProjectStateSnapshot(payload.targetState);
}