import {
  createProjectDeviceRowSyncProjectCommand,
  projectDeviceSyncRowSnapshotFields,
  type ProjectDeviceRowSyncProjectCommand,
  type ProjectDeviceSyncRowSnapshot,
} from "../models/project-device-row-sync-project-command.model.js";
import {
  projectDeviceSyncFields,
  type ProjectDeviceSyncField,
} from "../../shared/constants/project-device-sync-fields.js";
import {
  parseOverriddenFields,
  serializeOverriddenFields,
} from "./project-device-overrides.js";

export {
  parseOverriddenFields,
  serializeOverriddenFields,
} from "./project-device-overrides.js";

export type ProjectDeviceSyncSource = {
  id: string;
} & Pick<ProjectDeviceSyncRowSnapshot, ProjectDeviceSyncField>;

export type LinkedProjectDeviceRow = ProjectDeviceSyncRowSnapshot & {
  id: string;
  circuitId: string;
  equipmentIdentifier: string;
  circuitDisplayName: string | null;
  circuitListId: string;
  circuitListName: string;
  distributionBoardId: string;
  distributionBoardName: string;
};

export interface ProjectDeviceSyncSourceReader {
  findById(
    projectId: string,
    projectDeviceId: string
  ): Promise<ProjectDeviceSyncSource | null>;
}

export interface LinkedProjectDeviceRowReader {
  listLinkedByProjectDevice(
    projectId: string,
    projectDeviceId: string
  ): Promise<LinkedProjectDeviceRow[]>;
}

export interface ProjectDeviceSyncDependencies {
  projectDeviceRepository: ProjectDeviceSyncSourceReader;
  deviceRowRepository: LinkedProjectDeviceRowReader;
}

function sourceValue(
  projectDevice: ProjectDeviceSyncSource,
  field: ProjectDeviceSyncField
) {
  return projectDevice[field];
}

function valuesEqual(left: unknown, right: unknown) {
  return (left ?? null) === (right ?? null);
}

function buildDifferences(
  projectDevice: ProjectDeviceSyncSource,
  row: LinkedProjectDeviceRow
) {
  return projectDeviceSyncFields
    .filter((field) => !valuesEqual(row[field], sourceValue(projectDevice, field)))
    .map((field) => ({
      field,
      currentValue: row[field] ?? null,
      sourceValue: sourceValue(projectDevice, field) ?? null,
      isOverridden: parseOverriddenFields(row.overriddenFields).includes(field),
    }));
}

export class ProjectDeviceSyncService {
  private readonly projectDeviceRepository: ProjectDeviceSyncSourceReader;
  private readonly deviceRowRepository: LinkedProjectDeviceRowReader;

  constructor(deps: ProjectDeviceSyncDependencies) {
    this.projectDeviceRepository = deps.projectDeviceRepository;
    this.deviceRowRepository = deps.deviceRowRepository;
  }

  async getPreview(projectId: string, projectDeviceId: string) {
    const projectDevice = await this.projectDeviceRepository.findById(projectId, projectDeviceId);
    if (!projectDevice) {
      throw new Error("Project device not found.");
    }
    const rows = await this.deviceRowRepository.listLinkedByProjectDevice(projectId, projectDeviceId);

    return {
      projectDevice: {
        id: projectDevice.id,
        name: projectDevice.name,
        displayName: projectDevice.displayName,
      },
      rows: rows.map((row) => ({
        rowId: row.id,
        circuitId: row.circuitId,
        equipmentIdentifier: row.equipmentIdentifier,
        circuitDisplayName: row.circuitDisplayName,
        circuitListId: row.circuitListId,
        circuitListName: row.circuitListName,
        distributionBoardId: row.distributionBoardId,
        distributionBoardName: row.distributionBoardName,
        rowDisplayName: row.displayName,
        overriddenFields: parseOverriddenFields(row.overriddenFields),
        differences: buildDifferences(projectDevice, row),
      })),
    };
  }

  async createSynchronizeCommand(
    projectId: string,
    projectDeviceId: string,
    rowIds: string[],
    fields: ProjectDeviceSyncField[]
  ): Promise<ProjectDeviceRowSyncProjectCommand> {
    const projectDevice = await this.projectDeviceRepository.findById(projectId, projectDeviceId);
    if (!projectDevice) {
      throw new Error("Project device not found.");
    }
    const linkedRows = await this.deviceRowRepository.listLinkedByProjectDevice(projectId, projectDeviceId);
    const selectedRows = this.resolveSelectedRows(linkedRows, rowIds);
    const selectedFields = [...new Set(fields)];
    const assignments = selectedRows.flatMap((row) => {
      const expected = toSyncSnapshot(row);
      const target = { ...expected };
      for (const field of selectedFields) {
        Object.assign(target, {
          [field]: sourceValue(projectDevice, field) ?? null,
        });
      }
      const remainingOverrides = parseOverriddenFields(row.overriddenFields).filter(
        (field) => !selectedFields.includes(field)
      );
      target.overriddenFields =
        serializeOverriddenFields(remainingOverrides) ?? null;
      return snapshotsEqual(expected, target)
        ? []
        : [{ rowId: row.id, expected, target }];
    });

    return createProjectDeviceRowSyncProjectCommand(
      projectDeviceId,
      "synchronize",
      assignments
    );
  }

  async createDisconnectCommand(
    projectId: string,
    projectDeviceId: string,
    rowIds: string[]
  ): Promise<ProjectDeviceRowSyncProjectCommand> {
    const projectDevice = await this.projectDeviceRepository.findById(
      projectId,
      projectDeviceId
    );
    if (!projectDevice) {
      throw new Error("Project device not found.");
    }
    const linkedRows = await this.deviceRowRepository.listLinkedByProjectDevice(projectId, projectDeviceId);
    const selectedRows = this.resolveSelectedRows(linkedRows, rowIds);
    return createProjectDeviceRowSyncProjectCommand(
      projectDeviceId,
      "disconnect",
      selectedRows.map((row) => {
        const expected = toSyncSnapshot(row);
        return {
          rowId: row.id,
          expected,
          target: {
            ...expected,
            linkedProjectDeviceId: null,
          },
        };
      })
    );
  }

  private resolveSelectedRows(
    linkedRows: LinkedProjectDeviceRow[],
    rowIds: string[]
  ) {
    const uniqueRowIds = [...new Set(rowIds)];
    const byId = new Map(linkedRows.map((row) => [row.id, row]));
    const selectedRows = uniqueRowIds
      .map((rowId) => byId.get(rowId))
      .filter(Boolean) as LinkedProjectDeviceRow[];
    if (selectedRows.length !== uniqueRowIds.length) {
      throw new Error("One or more rows are not linked to this project device.");
    }
    return selectedRows;
  }

}

function toSyncSnapshot(
  row: LinkedProjectDeviceRow
): ProjectDeviceSyncRowSnapshot {
  return {
    linkedProjectDeviceId: row.linkedProjectDeviceId,
    name: row.name,
    displayName: row.displayName,
    phaseType: row.phaseType,
    connectionKind: row.connectionKind,
    costGroup: row.costGroup,
    category: row.category,
    quantity: row.quantity,
    powerPerUnit: row.powerPerUnit,
    simultaneityFactor: row.simultaneityFactor,
    cosPhi: row.cosPhi,
    remark: row.remark,
    overriddenFields: row.overriddenFields,
  };
}

function snapshotsEqual(
  left: ProjectDeviceSyncRowSnapshot,
  right: ProjectDeviceSyncRowSnapshot
) {
  return projectDeviceSyncRowSnapshotFields.every(
    (field) => left[field] === right[field]
  );
}