package me.bill.fakePlayerPlugin.util;

import me.bill.fakePlayerPlugin.FakePlayerPlugin;
import org.bukkit.configuration.file.YamlConfiguration;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

public final class YamlFileSyncer {

  private YamlFileSyncer() {
  }

  public record SyncResult(String fileName, List<String> keysAdded) {

    public boolean hasChanges() {
      return !keysAdded.isEmpty();
    }

    public int count() {
      return keysAdded.size();
    }
  }

  public static SyncResult syncMissingKeys(
      FakePlayerPlugin plugin, String diskRelPath, String jarResourcePath) {
    File diskFile = new File(plugin.getDataFolder(), diskRelPath);
    String fileName = diskFile.getName();

    if (!diskFile.exists()) {
      diskFile.getParentFile().mkdirs();
      plugin.saveResource(jarResourcePath, false);
      FppLogger.debug("YamlFileSyncer: extracted " + fileName + " from JAR (first run).");
      return new SyncResult(fileName, List.of());
    }

    InputStream jarStream = plugin.getResource(jarResourcePath);
    if (jarStream == null) {
      FppLogger.warn("YamlFileSyncer: JAR resource not found: " + jarResourcePath);
      return new SyncResult(fileName, List.of());
    }

    YamlConfiguration jarCfg;
    YamlConfiguration diskCfg;
    try (jarStream) {
      jarCfg =
          YamlConfiguration.loadConfiguration(
              new InputStreamReader(jarStream, StandardCharsets.UTF_8));
      diskCfg = YamlConfiguration.loadConfiguration(diskFile);
    } catch (IOException e) {
      FppLogger.warn(
          "YamlFileSyncer: failed to read files for " + fileName + ": " + e.getMessage());
      return new SyncResult(fileName, List.of());
    } catch (RuntimeException e) {

      FppLogger.warn(
          "YamlFileSyncer: could not parse disk file '"
              + fileName
              + "' - it may be corrupted or contain unknown serializable types"
              + " (e.g. from another plugin). Skipping sync. Cause: "
              + e.getMessage());
      return new SyncResult(fileName, List.of());
    }

    List<String> missing = new ArrayList<>();
    for (String key : jarCfg.getKeys(true)) {
      if (jarCfg.isConfigurationSection(key)) continue;
      if (!diskCfg.contains(key)) missing.add(key);
    }

    if (missing.isEmpty()) {
      FppLogger.debug("YamlFileSyncer: " + fileName + " is up to date - no keys missing.");
      return new SyncResult(fileName, List.of());
    }

    for (String key : missing) {
      diskCfg.set(key, jarCfg.get(key));
    }

    try {
      diskCfg.save(diskFile);
    } catch (IOException e) {
      FppLogger.warn("YamlFileSyncer: failed to save " + fileName + ": " + e.getMessage());
      return new SyncResult(fileName, List.of());
    }

    FppLogger.info(
        "YamlFileSyncer: "
            + fileName
            + " - added "
            + missing.size()
            + " new key(s) from JAR defaults: "
            + String.join(", ", missing));
    return new SyncResult(fileName, Collections.unmodifiableList(missing));
  }

  public static int countMissingKeys(
      FakePlayerPlugin plugin, String diskRelPath, String jarResourcePath) {
    File diskFile = new File(plugin.getDataFolder(), diskRelPath);
    if (!diskFile.exists()) return -1;

    InputStream jarStream = plugin.getResource(jarResourcePath);
    if (jarStream == null) return 0;

    YamlConfiguration jarCfg;
    YamlConfiguration diskCfg;
    try (jarStream) {
      jarCfg =
          YamlConfiguration.loadConfiguration(
              new InputStreamReader(jarStream, StandardCharsets.UTF_8));
      diskCfg = YamlConfiguration.loadConfiguration(diskFile);
    } catch (IOException e) {
      return 0;
    } catch (RuntimeException e) {
      FppLogger.warn(
          "YamlFileSyncer: could not parse disk file for countMissingKeys"
              + " - skipping. Cause: "
              + e.getMessage());
      return 0;
    }

    int count = 0;
    for (String key : jarCfg.getKeys(true)) {
      if (jarCfg.isConfigurationSection(key)) continue;
      if (!diskCfg.contains(key)) count++;
    }
    return count;
  }

  public static int countJarKeys(FakePlayerPlugin plugin, String jarResourcePath) {
    InputStream jarStream = plugin.getResource(jarResourcePath);
    if (jarStream == null) return 0;
    try (jarStream) {
      YamlConfiguration jarCfg =
          YamlConfiguration.loadConfiguration(
              new InputStreamReader(jarStream, StandardCharsets.UTF_8));
      int count = 0;
      for (String key : jarCfg.getKeys(true)) {
        if (!jarCfg.isConfigurationSection(key)) count++;
      }
      return count;
    } catch (IOException e) {
      return 0;
    }
  }
}