import {
  assertCircuitInsertProjectCommand,
  circuitInsertCommandType,
  circuitStructureCommandSchemaVersion,
  type CircuitSnapshot,
} from "./circuit-structure-project-command.model.js";
import {
  assertDistributionBoardUpdateProjectCommand,
  type DistributionBoardUpdateProjectCommand,
} from "./distribution-board-project-command.model.js";
import type { SerializedProjectCommand } from "./project-command.model.js";

export const distributionBoardCreateFeederCircuitCommandType =
  "distribution-board.create-feeder-circuit" as const;
export const distributionBoardRemoveFeederCircuitCommandType =
  "distribution-board.remove-feeder-circuit" as const;
export const distributionBoardFeederCircuitCommandSchemaVersion = 1 as const;

export interface DistributionBoardFeederCircuitCommandPayload {
  circuit: CircuitSnapshot;
  boardUpdate: DistributionBoardUpdateProjectCommand;
}

export interface DistributionBoardCreateFeederCircuitProjectCommand
  extends SerializedProjectCommand<DistributionBoardFeederCircuitCommandPayload> {
  schemaVersion: typeof distributionBoardFeederCircuitCommandSchemaVersion;
  type: typeof distributionBoardCreateFeederCircuitCommandType;
}

export interface DistributionBoardRemoveFeederCircuitProjectCommand
  extends SerializedProjectCommand<DistributionBoardFeederCircuitCommandPayload> {
  schemaVersion: typeof distributionBoardFeederCircuitCommandSchemaVersion;
  type: typeof distributionBoardRemoveFeederCircuitCommandType;
}

export type DistributionBoardFeederCircuitProjectCommand =
  | DistributionBoardCreateFeederCircuitProjectCommand
  | DistributionBoardRemoveFeederCircuitProjectCommand;

export function createDistributionBoardCreateFeederCircuitProjectCommand(
  circuit: CircuitSnapshot,
  boardUpdate: DistributionBoardUpdateProjectCommand
): DistributionBoardCreateFeederCircuitProjectCommand {
  const command: DistributionBoardCreateFeederCircuitProjectCommand = {
    schemaVersion: distributionBoardFeederCircuitCommandSchemaVersion,
    type: distributionBoardCreateFeederCircuitCommandType,
    payload: { circuit, boardUpdate },
  };
  assertDistributionBoardFeederCircuitProjectCommand(command);
  return command;
}

export function createDistributionBoardRemoveFeederCircuitProjectCommand(
  circuit: CircuitSnapshot,
  boardUpdate: DistributionBoardUpdateProjectCommand
): DistributionBoardRemoveFeederCircuitProjectCommand {
  const command: DistributionBoardRemoveFeederCircuitProjectCommand = {
    schemaVersion: distributionBoardFeederCircuitCommandSchemaVersion,
    type: distributionBoardRemoveFeederCircuitCommandType,
    payload: { circuit, boardUpdate },
  };
  assertDistributionBoardFeederCircuitProjectCommand(command);
  return command;
}

export function assertDistributionBoardFeederCircuitProjectCommand(
  command: SerializedProjectCommand<unknown>
): asserts command is DistributionBoardFeederCircuitProjectCommand {
  if (
    command.schemaVersion !==
      distributionBoardFeederCircuitCommandSchemaVersion ||
    (command.type !== distributionBoardCreateFeederCircuitCommandType &&
      command.type !== distributionBoardRemoveFeederCircuitCommandType) ||
    !isPlainObject(command.payload)
  ) {
    throw new Error("Unsupported distribution-board feeder-circuit command.");
  }

  const { circuit, boardUpdate } = command.payload;
  if (!isPlainObject(boardUpdate)) {
    throw new Error("Feeder-circuit command requires a board update.");
  }
  assertCircuitInsertProjectCommand({
    schemaVersion: circuitStructureCommandSchemaVersion,
    type: circuitInsertCommandType,
    payload: { circuit },
  });
  const boardUpdateCommand =
    boardUpdate as unknown as SerializedProjectCommand<unknown>;
  assertDistributionBoardUpdateProjectCommand(boardUpdateCommand);

  const typedCircuit = circuit as CircuitSnapshot;
  const typedBoardUpdate: DistributionBoardUpdateProjectCommand =
    boardUpdateCommand;
  if (typedCircuit.deviceRows.length !== 0 || !typedCircuit.isReserve) {
    throw new Error(
      "A generated feeder circuit must be empty before the board load is linked."
    );
  }
  const feedingBoard = getChangeValue(
    typedBoardUpdate,
    "feedingDistributionBoardId"
  );
  const feedingCircuit = getChangeValue(
    typedBoardUpdate,
    "feedingCircuitId"
  );
  if (feedingBoard === undefined || feedingCircuit === undefined) {
    throw new Error(
      "Feeder-circuit commands must update both logical feeding references."
    );
  }
  if (
    command.type === distributionBoardCreateFeederCircuitCommandType &&
    (typeof feedingBoard !== "string" || feedingCircuit !== typedCircuit.id)
  ) {
    throw new Error(
      "The created feeder circuit must be linked by the distribution-board update."
    );
  }
}

function getChangeValue(
  command: DistributionBoardUpdateProjectCommand,
  field: "feedingDistributionBoardId" | "feedingCircuitId"
) {
  return command.payload.changes.find((change) => change.field === field)?.value;
}

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