using System.Collections.ObjectModel;

using Microsoft.Extensions.Logging;

namespace File_Folder_Helper.ADO2025.PI6;

internal static partial class Helper20250618 {

    private record Record(string Directory, List<string> Files);

    internal static void MoveAllButXOfEach(ILogger<Worker> logger, List<string> args) {
        int keep = int.Parse(args[5]);
        logger.LogInformation(args[0]);
        logger.LogInformation(args[1]);
        logger.LogInformation(args[2]);
        string searchPattern = args[2];
        string split = args[4].Split('~')[0];
        string sourceDirectory = Path.GetFullPath(args[0].Split('~')[0]);
        string destinationDirectory = Path.GetFullPath(args[3].Split('~')[0]);
        if (destinationDirectory.Contains(sourceDirectory)) {
            throw new Exception("Not allowed!");
        }
        ReadOnlyCollection<string> directories = GetDirectories(sourceDirectory);
        MoveAllButXOfEachB(logger, searchPattern, sourceDirectory, destinationDirectory, split, keep, directories);
    }

    private static ReadOnlyCollection<string> GetDirectories(string sourceDirectory) {
        List<string> results = [sourceDirectory];
        results.AddRange(Directory.GetDirectories(sourceDirectory, "*", SearchOption.AllDirectories));
        return results.AsReadOnly();
    }

    private static void MoveAllButXOfEachB(ILogger<Worker> logger, string searchPattern, string sourceDirectory, string destinationDirectory, string split, int keep, ReadOnlyCollection<string> directories) {
        string[] files;
        int sourceDirectoryLength = sourceDirectory.Length;
        ReadOnlyDictionary<string, ReadOnlyCollection<string>> keyValuePairs;
        foreach (string directory in directories) {
            files = Directory.GetFiles(directory, searchPattern, SearchOption.TopDirectoryOnly);
            keyValuePairs = GetFiles(split, files);
            foreach (KeyValuePair<string, ReadOnlyCollection<string>> keyValuePair in keyValuePairs) {
                if (keyValuePair.Value.Count <= keep) {
                    continue;
                } else {
                    MoveAllButXOfEachC(logger, sourceDirectoryLength, destinationDirectory, keyValuePair);
                }
            }
        }
    }

    private static ReadOnlyDictionary<string, ReadOnlyCollection<string>> GetFiles(string split, string[] files) {
        Dictionary<string, ReadOnlyCollection<string>> results = [];
        string key;
        List<string>? collection;
        Dictionary<string, List<string>> keyValuePairs = [];
        foreach (string file in files) {
            key = Path.GetFileName(file).Split(split)[0];
            if (!keyValuePairs.TryGetValue(key, out collection)) {
                keyValuePairs.Add(key, []);
                if (!keyValuePairs.TryGetValue(key, out collection)) {
                    throw new Exception();
                }
            }
            collection.Add(file);
        }
        foreach (KeyValuePair<string, List<string>> keyValuePair in keyValuePairs) {
            results.Add(keyValuePair.Key, keyValuePair.Value.OrderByDescending(l => l).ToArray().AsReadOnly());
        }
        return results.AsReadOnly();
    }

    private static void MoveAllButXOfEachC(ILogger<Worker> logger, int sourceDirectoryLength, string destinationDirectory, KeyValuePair<string, ReadOnlyCollection<string>> keyValuePair) {
        string file;
        string checkFile;
        string checkDirectory;
        for (int i = 1; i < keyValuePair.Value.Count; i++) {
            file = keyValuePair.Value[i];
            checkFile = $"{destinationDirectory}{file[sourceDirectoryLength..]}";
            checkDirectory = Path.GetDirectoryName(checkFile) ?? throw new Exception();
            if (!Directory.Exists(checkDirectory))
                _ = Directory.CreateDirectory(checkDirectory);
            if (File.Exists(checkFile))
                continue;
            File.Move(file, checkFile);
            logger.LogInformation("<{file}> moved", file);
        }
    }

}