import type { ExternalModelObjectSnapshot } from "../../external-model/domain/external-model-contracts.js";
import {
  assertCircuitDeviceRowInsertProjectCommand,
  circuitDeviceRowInsertCommandType,
  circuitDeviceRowStructureCommandSchemaVersion,
  type CircuitDeviceRowSnapshot,
} from "./circuit-device-row-structure-project-command.model.js";
import type { SerializedProjectCommand } from "./project-command.model.js";
import { parseExternalModelStateSnapshot } from "./project-state-snapshot.model.js";

export const externalObjectAssignToNewRowCommandType =
  "external-object.assign-to-new-row" as const;
export const externalObjectDeleteCreatedRowCommandType =
  "external-object.unassign-and-delete-created-row" as const;
export const externalObjectNewRowCommandSchemaVersion = 1 as const;

export interface ExternalObjectNewRowPayload {
  row: CircuitDeviceRowSnapshot;
  objects: Array<{
    expected: ExternalModelObjectSnapshot;
    target: ExternalModelObjectSnapshot;
  }>;
  confirmedConflictObjectIds: string[];
}

export interface ExternalObjectNewRowProjectCommand
  extends SerializedProjectCommand<ExternalObjectNewRowPayload> {
  schemaVersion: typeof externalObjectNewRowCommandSchemaVersion;
  type:
    | typeof externalObjectAssignToNewRowCommandType
    | typeof externalObjectDeleteCreatedRowCommandType;
}

export function createExternalObjectNewRowProjectCommand(
  type: ExternalObjectNewRowProjectCommand["type"],
  payload: ExternalObjectNewRowPayload
): ExternalObjectNewRowProjectCommand {
  const command: ExternalObjectNewRowProjectCommand = {
    schemaVersion: externalObjectNewRowCommandSchemaVersion,
    type,
    payload: {
      row: {
        ...payload.row,
        manualQuantity: payload.row.manualQuantity ?? payload.row.quantity,
      },
      objects: payload.objects,
      confirmedConflictObjectIds: [...payload.confirmedConflictObjectIds],
    },
  };
  assertExternalObjectNewRowProjectCommand(command);
  return command;
}

export function invertExternalObjectNewRowProjectCommand(
  command: ExternalObjectNewRowProjectCommand
) {
  return createExternalObjectNewRowProjectCommand(
    command.type === externalObjectAssignToNewRowCommandType
      ? externalObjectDeleteCreatedRowCommandType
      : externalObjectAssignToNewRowCommandType,
    {
      row: command.payload.row,
      objects: command.payload.objects.map(({ expected, target }) => ({
        expected: target,
        target: expected,
      })),
      confirmedConflictObjectIds: command.payload.confirmedConflictObjectIds,
    }
  );
}

export function assertExternalObjectNewRowProjectCommand(
  command: SerializedProjectCommand<unknown>
): asserts command is ExternalObjectNewRowProjectCommand {
  if (
    command.schemaVersion !== externalObjectNewRowCommandSchemaVersion ||
    (command.type !== externalObjectAssignToNewRowCommandType &&
      command.type !== externalObjectDeleteCreatedRowCommandType) ||
    !isRecord(command.payload) ||
    !Array.isArray(command.payload.objects) ||
    command.payload.objects.length === 0 ||
    !Array.isArray(command.payload.confirmedConflictObjectIds)
  ) {
    throw new Error("Unsupported external object new-row command.");
  }
  const row = parseRow(command.payload.row);
  if (row.manualQuantity !== 0) {
    throw new Error("An external-only device row must start with zero manual quantity.");
  }
  const objectIds = new Set<string>();
  for (const transition of command.payload.objects) {
    if (!isRecord(transition)) throw new Error("Invalid external object transition.");
    const expected = parseObject(transition.expected);
    const target = parseObject(transition.target);
    if (expected.id !== target.id || objectIds.has(expected.id)) {
      throw new Error("New-row assignment contains mismatched or duplicate objects.");
    }
    objectIds.add(expected.id);
    const assigning = command.type === externalObjectAssignToNewRowCommandType;
    if (
      (assigning && (expected.circuitDeviceRowId !== null || target.circuitDeviceRowId !== row.id)) ||
      (!assigning && (expected.circuitDeviceRowId !== row.id || target.circuitDeviceRowId !== null))
    ) {
      throw new Error("External object links do not match the new-row action.");
    }
    assertOnlyAssignmentChanged(expected, target);
  }
  const confirmedIds = new Set<string>();
  for (const objectId of command.payload.confirmedConflictObjectIds) {
    if (typeof objectId !== "string" || !objectIds.has(objectId) || confirmedIds.has(objectId)) {
      throw new Error("New-row assignment contains an invalid conflict confirmation.");
    }
    confirmedIds.add(objectId);
  }
}

function parseRow(value: unknown): CircuitDeviceRowSnapshot {
  const envelope = {
    schemaVersion: circuitDeviceRowStructureCommandSchemaVersion,
    type: circuitDeviceRowInsertCommandType,
    payload: { row: value },
  };
  assertCircuitDeviceRowInsertProjectCommand(envelope);
  const row = envelope.payload.row;
  if (row.manualQuantity === undefined) {
    throw new Error("External object new-row command requires manual quantity.");
  }
  return row;
}

function parseObject(value: unknown): ExternalModelObjectSnapshot {
  return parseExternalModelStateSnapshot({
    source: null,
    importBatches: [],
    roomMappings: [],
    objects: [value],
  }).objects[0]!;
}

function assertOnlyAssignmentChanged(
  expected: ExternalModelObjectSnapshot,
  target: ExternalModelObjectSnapshot
) {
  const expectedRest = { ...expected, circuitDeviceRowId: null };
  const targetRest = { ...target, circuitDeviceRowId: null };
  if (canonicalJson(expectedRest) !== canonicalJson(targetRest)) {
    throw new Error("New-row assignment may only change the external object row link.");
  }
}

function canonicalJson(value: unknown): string {
  if (Array.isArray(value)) return `[${value.map(canonicalJson).join(",")}]`;
  if (isRecord(value)) {
    return `{${Object.keys(value).sort().map((key) =>
      `${JSON.stringify(key)}:${canonicalJson(value[key])}`
    ).join(",")}}`;
  }
  return JSON.stringify(value);
}

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