import type { SerializedProjectCommand } from "./project-command.model.js";

export const circuitSectionRenumberCommandType =
  "circuit.renumber-section" as const;
export const circuitSectionRenumberCommandSchemaVersion = 1 as const;

export interface CircuitSectionRenumberAssignment {
  circuitId: string;
  expectedEquipmentIdentifier: string;
  targetEquipmentIdentifier: string;
}

export interface CircuitSectionRenumberCommandPayload {
  sectionId: string;
  assignments: CircuitSectionRenumberAssignment[];
}

export interface CircuitSectionRenumberProjectCommand
  extends SerializedProjectCommand<CircuitSectionRenumberCommandPayload> {
  schemaVersion: typeof circuitSectionRenumberCommandSchemaVersion;
  type: typeof circuitSectionRenumberCommandType;
}

export function createCircuitSectionRenumberProjectCommand(
  sectionId: string,
  assignments: CircuitSectionRenumberAssignment[]
): CircuitSectionRenumberProjectCommand {
  const command: CircuitSectionRenumberProjectCommand = {
    schemaVersion: circuitSectionRenumberCommandSchemaVersion,
    type: circuitSectionRenumberCommandType,
    payload: { sectionId, assignments },
  };
  assertCircuitSectionRenumberProjectCommand(command);
  return command;
}

export function assertCircuitSectionRenumberProjectCommand(
  command: SerializedProjectCommand<unknown>
): asserts command is CircuitSectionRenumberProjectCommand {
  if (
    command.schemaVersion !==
      circuitSectionRenumberCommandSchemaVersion ||
    command.type !== circuitSectionRenumberCommandType
  ) {
    throw new Error("Unsupported circuit section renumber command.");
  }
  if (!isPlainObject(command.payload)) {
    throw new Error(
      "Circuit section renumber payload must be an object."
    );
  }
  const { sectionId, assignments } = command.payload;
  assertNonEmptyString(sectionId, "sectionId");
  if (!Array.isArray(assignments) || assignments.length === 0) {
    throw new Error(
      "Circuit section renumber command requires assignments."
    );
  }

  const circuitIds = new Set<string>();
  const expectedIdentifiers = new Set<string>();
  const targetIdentifiers = new Set<string>();
  let hasChangedIdentifier = false;
  for (const assignment of assignments) {
    if (!isPlainObject(assignment)) {
      throw new Error(
        "Circuit section renumber command contains an invalid assignment."
      );
    }
    assertNonEmptyString(assignment.circuitId, "circuitId");
    assertNonEmptyString(
      assignment.expectedEquipmentIdentifier,
      "expectedEquipmentIdentifier"
    );
    assertNonEmptyString(
      assignment.targetEquipmentIdentifier,
      "targetEquipmentIdentifier"
    );
    if (circuitIds.has(assignment.circuitId)) {
      throw new Error(
        "Circuit section renumber command contains duplicate circuit ids."
      );
    }
    if (
      expectedIdentifiers.has(
        assignment.expectedEquipmentIdentifier
      )
    ) {
      throw new Error(
        "Circuit section renumber command contains duplicate expected identifiers."
      );
    }
    if (
      targetIdentifiers.has(assignment.targetEquipmentIdentifier)
    ) {
      throw new Error(
        "Circuit section renumber command contains duplicate target identifiers."
      );
    }
    if (
      assignment.expectedEquipmentIdentifier !==
      assignment.targetEquipmentIdentifier
    ) {
      hasChangedIdentifier = true;
    }
    circuitIds.add(assignment.circuitId);
    expectedIdentifiers.add(
      assignment.expectedEquipmentIdentifier
    );
    targetIdentifiers.add(assignment.targetEquipmentIdentifier);
  }
  if (!hasChangedIdentifier) {
    throw new Error(
      "Circuit section renumber command must change at least one identifier."
    );
  }
}

function assertNonEmptyString(
  value: unknown,
  field: string
): asserts value is string {
  if (typeof value !== "string" || !value.trim()) {
    throw new Error(`${field} must be a non-empty string.`);
  }
}

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