import { Injectable, Inject } from '@nestjs/common';
import { DynamoDBClient } from '@aws-sdk/client-dynamodb';
import {
  DynamoDBDocumentClient,
  GetCommand,
  PutCommand,
  DeleteCommand,
  TranslateConfig,
} from '@aws-sdk/lib-dynamodb';
import { DadosferaLogger } from '@dadosfera/dadosfera-logs';
import { v4 as uuid } from 'uuid';
import { DYNAMODB_CONFIG } from './dynamodb.config';

export interface ReferenceColumn {
  name: string;
  type: string;
}

export interface InputDocument {
  id: string;
  client_id: string;
  user_id: string;
  created_at: string;
  name: string;
  description?: string;
  plugin: string;
  type: string;
  tables?: Array<{
    name: string;
    type: string;
    columns?: string[];
    reference_column?: ReferenceColumn;
  }>;
  credentials?: Record<string, any>;
}

@Injectable()
export class DynamoDBService {
  private documentClient: DynamoDBDocumentClient;
  private logger: any;

  constructor(
    @Inject(DadosferaLogger) dadosferaLogger: DadosferaLogger,
  ) {
    this.logger = dadosferaLogger.logger;

    const dynamoConfig = { region: DYNAMODB_CONFIG.region() };
    const marshallOptions: TranslateConfig = {
      marshallOptions: {
        removeUndefinedValues: true,
      },
    };

    const dynamoDb = new DynamoDBClient(dynamoConfig);
    this.documentClient = DynamoDBDocumentClient.from(dynamoDb, marshallOptions);
  }

  async createInput(
    clientId: string,
    userId: string,
    data: {
      name: string;
      description?: string;
      plugin: string;
      type: string;
      tables?: Array<{
        name: string;
        type: string;
        columns?: string[];
        reference_column?: ReferenceColumn;
      }>;
    },
  ): Promise<InputDocument> {
    const tableName = DYNAMODB_CONFIG.inputsTable();
    const id = uuid();
    const created_at = new Date().toISOString();

    const item: InputDocument = {
      id,
      client_id: clientId,
      user_id: userId,
      created_at,
      name: data.name,
      description: data.description,
      plugin: data.plugin,
      type: data.type,
      tables: data.tables,
    };

    this.logger.info('DynamoDB: Creating input', {
      tableName,
      inputId: id,
      plugin: data.plugin,
    });

    const putCommand = new PutCommand({
      TableName: tableName,
      Item: item,
    });

    try {
      await this.documentClient.send(putCommand);
      this.logger.info('DynamoDB: Input created successfully', { inputId: id });
      return item;
    } catch (error) {
      this.logger.error('DynamoDB: Failed to create input', {
        tableName,
        inputId: id,
        region: DYNAMODB_CONFIG.region(),
        error: error.message,
        errorName: error.name,
      });
      throw error;
    }
  }

  async findInput(clientId: string, inputId: string): Promise<InputDocument | null> {
    const tableName = DYNAMODB_CONFIG.inputsTable();

    const getCommand = new GetCommand({
      TableName: tableName,
      Key: {
        id: inputId,
        client_id: clientId,
      },
    });

    try {
      const { Item } = await this.documentClient.send(getCommand);
      return Item as InputDocument | null;
    } catch (error) {
      this.logger.error('DynamoDB: findInput failed', { inputId, clientId, error: error.message });
      throw error;
    }
  }

  async deleteInput(clientId: string, inputId: string): Promise<void> {
    const tableName = DYNAMODB_CONFIG.inputsTable();

    this.logger.info('DynamoDB: Deleting input', {
      tableName,
      inputId,
    });

    const deleteCommand = new DeleteCommand({
      TableName: tableName,
      Key: {
        id: inputId,
        client_id: clientId,
      },
    });

    await this.documentClient.send(deleteCommand);

    this.logger.info('DynamoDB: Input deleted successfully', { inputId });
  }

  /**
   * Update a specific table entry in the input document.
   * Fetches the current document, updates the matching table, and saves.
   */
  async updateInputTable(
    clientId: string,
    inputId: string,
    tableName: string,
    changes: {
      type?: string;
      columns?: string[];
      reference_column?: ReferenceColumn | null;
    },
  ): Promise<void> {
    const dynamoTableName = DYNAMODB_CONFIG.inputsTable();

    this.logger.info('DynamoDB: Updating input table', {
      inputId,
      tableName,
      changes: Object.keys(changes),
    });

    // Get current document
    const current = await this.findInput(clientId, inputId);
    if (!current) {
      this.logger.warn('DynamoDB: Input not found for update', { inputId });
      return;
    }

    // Find and update the matching table
    const tables = current.tables || [];
    const tableIndex = tables.findIndex((t) => t.name === tableName);

    if (tableIndex === -1) {
      this.logger.warn('DynamoDB: Table not found in input', {
        inputId,
        tableName,
      });
      return;
    }

    // Merge changes into the table entry
    const updatedTable = { ...tables[tableIndex] };
    if ('type' in changes) updatedTable.type = changes.type;
    if ('columns' in changes) updatedTable.columns = changes.columns;
    if ('reference_column' in changes) {
      if (changes.reference_column === null) {
        delete updatedTable.reference_column;
      } else {
        updatedTable.reference_column = changes.reference_column;
      }
    }
    tables[tableIndex] = updatedTable;

    // Save updated document
    const putCommand = new PutCommand({
      TableName: dynamoTableName,
      Item: {
        ...current,
        tables,
        updated_at: new Date().toISOString(),
      },
    });

    try {
      await this.documentClient.send(putCommand);
      this.logger.info('DynamoDB: Input table updated successfully', {
        inputId,
        tableName,
      });
    } catch (error) {
      this.logger.error('DynamoDB: Failed to update input table', {
        inputId,
        tableName,
        error: error.message,
      });
      throw error;
    }
  }

}