import crypto from "node:crypto";
import {
  circuitGroupCategories,
  type CircuitGroupCategory,
} from "../../shared/constants/circuit-group.js";
import {
  distributionBoardComponentPlacements,
  distributionBoardComponentRoles,
  type DistributionBoardComponentPlacement,
  type DistributionBoardComponentRole,
} from "../../shared/constants/distribution-board-component.js";
import {
  distributionBoardSupplyTypes,
  type DistributionBoardSupplyType,
} from "../../shared/constants/distribution-board.js";
import type {
  BreakerTripCharacteristic,
  FuseUtilizationCategory,
  ProtectionDeviceType,
  RcdType,
} from "../../shared/constants/protection-device.js";
import { protectionDeviceConfigurationSchema } from "../../shared/validation/protection-device.schemas.js";
import {
  assertCircuitInsertProjectCommand,
  circuitInsertCommandType,
  circuitStructureCommandSchemaVersion,
  type CircuitSnapshot,
} from "./circuit-structure-project-command.model.js";

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

export interface DistributionBoardSubtreeComponentProtectionSnapshot {
  componentId: string;
  type: ProtectionDeviceType;
  ratedCurrentA: number;
  fuseUtilizationCategory: FuseUtilizationCategory | null;
  tripCharacteristic: BreakerTripCharacteristic | null;
  rcdType: RcdType | null;
  ratedResidualCurrentMa: number | null;
}

export interface DistributionBoardSubtreeComponentSnapshot {
  component: {
    id: string;
    circuitListId: string;
    sectionId: string | null;
    equipmentIdentifier: string;
    name: string;
    role: DistributionBoardComponentRole;
    placement: DistributionBoardComponentPlacement;
    sortOrder: number;
  };
  protectionDevice:
    | DistributionBoardSubtreeComponentProtectionSnapshot
    | null;
}

export interface DistributionBoardSubtreeSnapshot {
  distributionBoard: {
    id: string;
    projectId: string;
    name: string;
    floorId: string | null;
    supplyType: DistributionBoardSupplyType | null;
    simultaneityFactor: number;
  };
  circuitList: {
    id: string;
    projectId: string;
    distributionBoardId: string;
    name: string;
  };
  sections: DistributionBoardSubtreeSectionSnapshot[];
  components: DistributionBoardSubtreeComponentSnapshot[];
  circuits: CircuitSnapshot[];
}

export function cloneDistributionBoardSubtree(
  source: DistributionBoardSubtreeSnapshot,
  name: string,
  createId: () => string = () => crypto.randomUUID()
): DistributionBoardSubtreeSnapshot {
  assertDistributionBoardSubtreeSnapshot(source);
  const normalizedName = name.trim();
  assertNonEmptyString(normalizedName, "name");

  const distributionBoardId = createId();
  const circuitListId = distributionBoardId;
  const sectionIds = new Map(
    source.sections.map((section) => [section.id, createId()])
  );
  const circuitIds = new Map(
    source.circuits.map((circuit) => [circuit.id, createId()])
  );
  const componentIds = new Map(
    source.components.map(({ component }) => [component.id, createId()])
  );

  const clone: DistributionBoardSubtreeSnapshot = {
    distributionBoard: {
      ...source.distributionBoard,
      id: distributionBoardId,
      name: normalizedName,
    },
    circuitList: {
      ...source.circuitList,
      id: circuitListId,
      distributionBoardId,
      name: `${normalizedName} Stromkreisliste`,
    },
    sections: source.sections.map((section) => ({
      ...section,
      id: requiredMappedId(sectionIds, section.id),
      circuitListId,
    })),
    components: source.components.map(
      ({ component, protectionDevice }) => {
        const componentId = requiredMappedId(
          componentIds,
          component.id
        );
        return {
          component: {
            ...component,
            id: componentId,
            circuitListId,
            sectionId:
              component.sectionId === null
                ? null
                : requiredMappedId(sectionIds, component.sectionId),
          },
          protectionDevice:
            protectionDevice === null
              ? null
              : { ...protectionDevice, componentId },
        };
      }
    ),
    circuits: source.circuits.map((circuit) => {
      const circuitId = requiredMappedId(circuitIds, circuit.id);
      return {
        ...circuit,
        id: circuitId,
        circuitListId,
        sectionId: requiredMappedId(sectionIds, circuit.sectionId),
        deviceRows: circuit.deviceRows.map((row) => ({
          ...row,
          id: createId(),
          circuitId,
        })),
        protectionDevice:
          circuit.protectionDevice === null ||
          circuit.protectionDevice === undefined
            ? null
            : { ...circuit.protectionDevice, circuitId },
      };
    }),
  };
  assertDistributionBoardSubtreeSnapshot(clone);
  return clone;
}

export function assertDistributionBoardSubtreeSnapshot(
  value: unknown
): asserts value is DistributionBoardSubtreeSnapshot {
  if (
    !isPlainObject(value) ||
    Object.keys(value).length !== 5 ||
    !isPlainObject(value.distributionBoard) ||
    !isPlainObject(value.circuitList) ||
    !Array.isArray(value.sections) ||
    !Array.isArray(value.components) ||
    !Array.isArray(value.circuits)
  ) {
    throw new Error("Distribution-board subtree snapshot is invalid.");
  }
  const board = value.distributionBoard;
  const list = value.circuitList;
  for (const field of ["id", "projectId", "name"] as const) {
    assertNonEmptyString(board[field], `distributionBoard.${field}`);
  }
  assertNullableString(board.floorId, "distributionBoard.floorId");
  if (
    board.supplyType !== null &&
    !distributionBoardSupplyTypes.includes(
      board.supplyType as DistributionBoardSupplyType
    )
  ) {
    throw new Error("Distribution-board supply type is invalid.");
  }
  assertFiniteNumber(
    board.simultaneityFactor,
    "distributionBoard.simultaneityFactor"
  );
  if (board.simultaneityFactor < 0 || board.simultaneityFactor > 1) {
    throw new Error("Distribution-board simultaneity factor is invalid.");
  }
  for (const field of [
    "id",
    "projectId",
    "distributionBoardId",
    "name",
  ] as const) {
    assertNonEmptyString(list[field], `circuitList.${field}`);
  }
  const circuitListId = list.id;
  assertNonEmptyString(circuitListId, "circuitList.id");
  if (
    list.projectId !== board.projectId ||
    list.distributionBoardId !== board.id
  ) {
    throw new Error("Distribution-board circuit list ownership is invalid.");
  }

  const sectionIds = new Set<string>();
  const sectionKeys = new Set<string>();
  const sectionPrefixes = new Set<string>();
  const categoryGroups = new Set<string>();
  for (const section of value.sections) {
    assertSection(section, circuitListId);
    registerUnique(sectionIds, section.id, "circuit-section id");
    registerUnique(sectionKeys, section.key, "circuit-section key");
    registerUnique(sectionPrefixes, section.prefix, "circuit-section prefix");
    if (section.category !== null && section.groupNumber !== null) {
      registerUnique(
        categoryGroups,
        `${section.category}:${section.groupNumber}`,
        "circuit-group number"
      );
    }
  }

  const equipmentIdentifiers = new Set<string>();
  const componentIds = new Set<string>();
  const fixedRoles = new Set<string>();
  const groupRoles = new Set<string>();
  for (const entry of value.components) {
    assertComponent(entry, circuitListId, sectionIds);
    const component = entry.component;
    registerUnique(componentIds, component.id, "component id");
    registerEquipmentIdentifier(
      equipmentIdentifiers,
      component.equipmentIdentifier
    );
    if (
      component.role === "main_switch" ||
      component.role === "surge_protective_device"
    ) {
      registerUnique(fixedRoles, component.role, "fixed component role");
    }
    if (
      component.role === "group_upstream_protection" ||
      component.role === "group_residual_current_protection"
    ) {
      registerUnique(
        groupRoles,
        `${component.sectionId}:${component.role}`,
        "group component role"
      );
    }
  }

  const circuitIds = new Set<string>();
  const deviceRowIds = new Set<string>();
  for (const circuit of value.circuits) {
    assertCircuitInsertProjectCommand({
      schemaVersion: circuitStructureCommandSchemaVersion,
      type: circuitInsertCommandType,
      payload: { circuit },
    });
    if (
      circuit.circuitListId !== circuitListId ||
      !sectionIds.has(circuit.sectionId) ||
      !("protectionDevice" in circuit)
    ) {
      throw new Error("Distribution-board circuit ownership is invalid.");
    }
    registerUnique(circuitIds, circuit.id, "circuit id");
    registerEquipmentIdentifier(
      equipmentIdentifiers,
      circuit.equipmentIdentifier
    );
    for (const row of circuit.deviceRows) {
      registerUnique(deviceRowIds, row.id, "device-row id");
    }
  }
}

function assertSection(
  value: unknown,
  circuitListId: string
): asserts value is DistributionBoardSubtreeSectionSnapshot {
  if (!isPlainObject(value) || Object.keys(value).length !== 8) {
    throw new Error("Distribution-board circuit section is invalid.");
  }
  for (const field of ["id", "circuitListId", "key", "displayName", "prefix"] as const) {
    assertNonEmptyString(value[field], `section.${field}`);
  }
  assertFiniteNumber(value.sortOrder, "section.sortOrder");
  if (value.circuitListId !== circuitListId) {
    throw new Error("Distribution-board section belongs to another list.");
  }
  if (
    value.category === null
      ? value.groupNumber !== null
      : !circuitGroupCategories.includes(
          value.category as CircuitGroupCategory
        ) ||
        !Number.isInteger(value.groupNumber) ||
        (value.groupNumber as number) <= 0
  ) {
    throw new Error("Distribution-board circuit group is invalid.");
  }
}

function assertComponent(
  value: unknown,
  circuitListId: string,
  sectionIds: ReadonlySet<string>
): asserts value is DistributionBoardSubtreeComponentSnapshot {
  if (
    !isPlainObject(value) ||
    Object.keys(value).length !== 2 ||
    !isPlainObject(value.component)
  ) {
    throw new Error("Distribution-board component snapshot is invalid.");
  }
  const component = value.component;
  for (const field of ["id", "circuitListId", "equipmentIdentifier", "name"] as const) {
    assertNonEmptyString(component[field], `component.${field}`);
  }
  if (
    component.circuitListId !== circuitListId ||
    !distributionBoardComponentRoles.includes(
      component.role as DistributionBoardComponentRole
    ) ||
    !distributionBoardComponentPlacements.includes(
      component.placement as DistributionBoardComponentPlacement
    )
  ) {
    throw new Error("Distribution-board component values are invalid.");
  }
  assertFiniteNumber(component.sortOrder, "component.sortOrder");
  assertNullableString(component.sectionId, "component.sectionId");
  const fixed =
    component.role === "main_switch" ||
    component.role === "surge_protective_device";
  const grouped =
    component.role === "group_upstream_protection" ||
    component.role === "group_residual_current_protection";
  if (
    (fixed &&
      (component.placement !== "header" || component.sectionId !== null)) ||
    (grouped &&
      (component.placement !== "group" ||
        typeof component.sectionId !== "string" ||
        !sectionIds.has(component.sectionId))) ||
    (component.role === "auxiliary" &&
      (component.placement !== "footer" || component.sectionId !== null))
  ) {
    throw new Error("Distribution-board component placement is invalid.");
  }
  if (value.protectionDevice === null) {
    if (grouped) {
      throw new Error("Group protection component lacks protection data.");
    }
    return;
  }
  if (!grouped || !isPlainObject(value.protectionDevice)) {
    throw new Error("Component protection data is invalid.");
  }
  const protection = value.protectionDevice;
  if (
    protection.componentId !== component.id ||
    !protectionDeviceConfigurationSchema.safeParse({
      type: protection.type,
      ratedCurrentA: protection.ratedCurrentA,
      ...(protection.fuseUtilizationCategory === null
        ? {}
        : { fuseUtilizationCategory: protection.fuseUtilizationCategory }),
      ...(protection.tripCharacteristic === null
        ? {}
        : { tripCharacteristic: protection.tripCharacteristic }),
      ...(protection.rcdType === null ? {} : { rcdType: protection.rcdType }),
      ...(protection.ratedResidualCurrentMa === null
        ? {}
        : { ratedResidualCurrentMa: protection.ratedResidualCurrentMa }),
    }).success
  ) {
    throw new Error("Component protection configuration is invalid.");
  }
}

function requiredMappedId(
  ids: ReadonlyMap<string, string>,
  sourceId: string
) {
  const id = ids.get(sourceId);
  if (!id) {
    throw new Error("Distribution-board copy reference is invalid.");
  }
  return id;
}

function registerEquipmentIdentifier(
  identifiers: Set<string>,
  value: string
) {
  registerUnique(
    identifiers,
    value.trim().toLocaleLowerCase("de"),
    "equipment identifier"
  );
}

function registerUnique(
  values: Set<string>,
  value: string,
  label: string
) {
  if (values.has(value)) {
    throw new Error(`Distribution-board subtree contains duplicate ${label}.`);
  }
  values.add(value);
}

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 assertNullableString(
  value: unknown,
  field: string
): asserts value is string | null {
  if (value !== null) {
    assertNonEmptyString(value, field);
  }
}

function assertFiniteNumber(
  value: unknown,
  field: string
): asserts value is number {
  if (typeof value !== "number" || !Number.isFinite(value)) {
    throw new Error(`${field} must be finite.`);
  }
}

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