package me.zinch.files;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.databind.DatabindException;
import com.fasterxml.jackson.dataformat.xml.XmlMapper;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlElementWrapper;
import com.fasterxml.jackson.dataformat.xml.annotation.JacksonXmlProperty;
import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
import me.zinch.exceptions.DbInitializationException;
import me.zinch.models.Product;

import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.util.List;
import java.util.Map;

/**
 * The DbController class provides methods for loading and saving product data to a database file.
 */
public class DbController {
  private static final XmlMapper xmlMapper = XmlMapper.builder().addModule(new JavaTimeModule()).build();
  private static final String path;

  static {
    Map<String, String> env = System.getenv();
    path = env.getOrDefault("DB_FILE", "");
    xmlMapper.setDefaultPropertyInclusion(JsonInclude.Include.NON_NULL);
  }

  /**
   * Represents a collection of products.
   */
  private static class Products {
    @JacksonXmlElementWrapper(useWrapping = false)
    @JacksonXmlProperty(localName = "Product")
    private List<Product> products;

    public Products() {}

    public Products(List<Product> list) {
      this.products = list;
    }

    public List<Product> getProducts() {
      return products;
    }
  }

  public static List<Product> loadDb() throws IOException {
    try {
      BufferedInputStream bufferedInputStream = new BufferedInputStream(new FileInputStream(path));
      Products collection = xmlMapper.readValue(bufferedInputStream, Products.class);
      bufferedInputStream.close();
      return collection.getProducts();
    } catch (FileNotFoundException e) {
      throw new FileNotFoundException("Не удалось найти файл " + path);
    } catch (DatabindException e) {
      throw new DbInitializationException();
    } catch (IOException e) {
      throw new IOException("Произошла неожиданная ошибка во время работы с файлом!");
    }
  }

  public static void saveDb(List<Product> list) throws IOException {
    try {
      OutputStreamWriter outputStreamWriter = new OutputStreamWriter(new FileOutputStream(path));
      xmlMapper.writeValue(outputStreamWriter, new Products(list));
      outputStreamWriter.close();
    } catch (FileNotFoundException e) {
      throw new FileNotFoundException(e.getMessage());
    } catch (IOException e) {
      throw new IOException(e);
    }
  }
}