import {
  circuitGroupCategories,
  type CircuitGroupCategory,
} from "../../shared/constants/circuit-group.js";
import { formatCircuitGroupPrefix } from "../services/circuit-group-numbering.js";
import type { SerializedProjectCommand } from "./project-command.model.js";

export const circuitGroupInsertCommandType = "circuit-group.insert" as const;
export const circuitGroupDeleteCommandType = "circuit-group.delete" as const;
export const circuitGroupUpdateCommandType = "circuit-group.update" as const;
export const circuitGroupStructureCommandSchemaVersion = 1 as const;

export interface CircuitGroupSnapshot {
  id: string;
  circuitListId: string;
  key: string;
  displayName: string;
  prefix: string;
  sortOrder: number;
  category: CircuitGroupCategory;
  groupNumber: number;
}

interface SnapshotPayload {
  snapshot: CircuitGroupSnapshot;
}

interface UpdatePayload {
  expected: CircuitGroupSnapshot;
  target: CircuitGroupSnapshot;
}

export interface CircuitGroupInsertProjectCommand
  extends SerializedProjectCommand<SnapshotPayload> {
  schemaVersion: typeof circuitGroupStructureCommandSchemaVersion;
  type: typeof circuitGroupInsertCommandType;
}

export interface CircuitGroupDeleteProjectCommand
  extends SerializedProjectCommand<SnapshotPayload> {
  schemaVersion: typeof circuitGroupStructureCommandSchemaVersion;
  type: typeof circuitGroupDeleteCommandType;
}

export interface CircuitGroupUpdateProjectCommand
  extends SerializedProjectCommand<UpdatePayload> {
  schemaVersion: typeof circuitGroupStructureCommandSchemaVersion;
  type: typeof circuitGroupUpdateCommandType;
}

export type CircuitGroupStructureProjectCommand =
  | CircuitGroupInsertProjectCommand
  | CircuitGroupDeleteProjectCommand
  | CircuitGroupUpdateProjectCommand;

export function createCircuitGroupInsertProjectCommand(
  snapshot: CircuitGroupSnapshot
): CircuitGroupInsertProjectCommand {
  const command: CircuitGroupInsertProjectCommand = {
    schemaVersion: circuitGroupStructureCommandSchemaVersion,
    type: circuitGroupInsertCommandType,
    payload: { snapshot },
  };
  assertCircuitGroupInsertProjectCommand(command);
  return command;
}

export function createCircuitGroupDeleteProjectCommand(
  snapshot: CircuitGroupSnapshot
): CircuitGroupDeleteProjectCommand {
  const command: CircuitGroupDeleteProjectCommand = {
    schemaVersion: circuitGroupStructureCommandSchemaVersion,
    type: circuitGroupDeleteCommandType,
    payload: { snapshot },
  };
  assertCircuitGroupDeleteProjectCommand(command);
  return command;
}

export function createCircuitGroupUpdateProjectCommand(
  expected: CircuitGroupSnapshot,
  target: CircuitGroupSnapshot
): CircuitGroupUpdateProjectCommand {
  const command: CircuitGroupUpdateProjectCommand = {
    schemaVersion: circuitGroupStructureCommandSchemaVersion,
    type: circuitGroupUpdateCommandType,
    payload: { expected, target },
  };
  assertCircuitGroupUpdateProjectCommand(command);
  return command;
}

export function assertCircuitGroupInsertProjectCommand(
  command: SerializedProjectCommand<unknown>
): asserts command is CircuitGroupInsertProjectCommand {
  assertSnapshotCommand(command, circuitGroupInsertCommandType);
}

export function assertCircuitGroupDeleteProjectCommand(
  command: SerializedProjectCommand<unknown>
): asserts command is CircuitGroupDeleteProjectCommand {
  assertSnapshotCommand(command, circuitGroupDeleteCommandType);
}

export function assertCircuitGroupUpdateProjectCommand(
  command: SerializedProjectCommand<unknown>
): asserts command is CircuitGroupUpdateProjectCommand {
  if (
    command.schemaVersion !== circuitGroupStructureCommandSchemaVersion ||
    command.type !== circuitGroupUpdateCommandType ||
    !isPlainObject(command.payload) ||
    Object.keys(command.payload).length !== 2
  ) {
    throw new Error("Unsupported circuit-group update command.");
  }
  assertCircuitGroupSnapshot(command.payload.expected);
  assertCircuitGroupSnapshot(command.payload.target);
  for (const field of [
    "id",
    "circuitListId",
    "key",
    "prefix",
    "sortOrder",
    "category",
    "groupNumber",
  ] as const) {
    if (command.payload.expected[field] !== command.payload.target[field]) {
      throw new Error(
        "Circuit-group updates can only change the display name."
      );
    }
  }
}

function assertSnapshotCommand(
  command: SerializedProjectCommand<unknown>,
  type:
    | typeof circuitGroupInsertCommandType
    | typeof circuitGroupDeleteCommandType
) {
  if (
    command.schemaVersion !== circuitGroupStructureCommandSchemaVersion ||
    command.type !== type ||
    !isPlainObject(command.payload) ||
    Object.keys(command.payload).length !== 1
  ) {
    throw new Error("Unsupported circuit-group structure command.");
  }
  assertCircuitGroupSnapshot(command.payload.snapshot);
}

export function assertCircuitGroupSnapshot(
  value: unknown
): asserts value is CircuitGroupSnapshot {
  if (!isPlainObject(value) || Object.keys(value).length !== 8) {
    throw new Error("Circuit-group snapshot is invalid.");
  }
  for (const field of [
    "id",
    "circuitListId",
    "key",
    "displayName",
    "prefix",
  ] as const) {
    if (typeof value[field] !== "string" || !value[field].trim()) {
      throw new Error(`${field} must be a non-empty string.`);
    }
  }
  if (
    !circuitGroupCategories.includes(
      value.category as CircuitGroupCategory
    ) ||
    !Number.isInteger(value.groupNumber) ||
    (value.groupNumber as number) < 1 ||
    !Number.isFinite(value.sortOrder)
  ) {
    throw new Error("Circuit-group category, number or order is invalid.");
  }
  if (
    value.prefix !==
    formatCircuitGroupPrefix(
      value.category as CircuitGroupCategory,
      value.groupNumber as number
    )
  ) {
    throw new Error("Circuit-group prefix does not match its category and number.");
  }
}

function isPlainObject(value: unknown): value is Record<string, unknown> {
  return value !== null && typeof value === "object" && !Array.isArray(value);
}