using Journal.Core.Dtos;
using Journal.Core.Repositories;

namespace Journal.Core.Services;

public sealed class EntryFileService(IEntryFileRepository repo) : IEntryFileService
{
    private readonly IEntryFileRepository _repo = repo ?? throw new ArgumentNullException(nameof(repo));

    public IReadOnlyList<EntryListItem> ListEntries(string dataDirectory)
    {
        return [.. _repo.ListMarkdownFiles(dataDirectory)
            .Select(path => new EntryListItem(
                FileName: _repo.GetFileName(path),
                FilePath: _repo.GetFullPath(path)))];
    }

    public EntryLoadResult LoadEntry(string filePath)
    {
        var normalizedPath = _repo.GetFullPath(filePath);
        if (!_repo.FileExists(normalizedPath))
            throw new FileNotFoundException($"Entry file not found: {normalizedPath}");

        var rawContent = HtmlSanitizer.StripRichHtml(_repo.ReadFile(normalizedPath));
        var fileStem = _repo.GetFileNameWithoutExtension(normalizedPath);
        var entry = JournalParser.ParseJournalContent(rawContent, fileStem);

        return new EntryLoadResult(
            Date: entry.Date,
            FileName: _repo.GetFileName(normalizedPath),
            FilePath: normalizedPath,
            RawContent: entry.RawContent);
    }

    public EntrySaveResult SaveEntry(EntrySavePayload payload, string defaultDataDirectory)
    {
        var targetPath = ResolveTargetPath(payload.FilePath, defaultDataDirectory);
        var mode = string.IsNullOrWhiteSpace(payload.Mode) ? "Daily" : payload.Mode.Trim();
        var sanitizedContent = HtmlSanitizer.StripRichHtml(payload.Content ?? "");
        _repo.EnsureDirectory(targetPath);

        if (string.Equals(mode, "Overwrite", StringComparison.OrdinalIgnoreCase))
        {
            _repo.WriteFile(targetPath, sanitizedContent);
            return new EntrySaveResult(targetPath);
        }

        if (string.Equals(mode, "Fragment", StringComparison.OrdinalIgnoreCase))
        {
            _repo.AppendFile(targetPath, "\n\n" + sanitizedContent.Trim());
            return new EntrySaveResult(targetPath);
        }

        string finalContent;
        if (_repo.FileExists(targetPath))
        {
            var existingContent = _repo.ReadFile(targetPath);
            var fileStem = _repo.GetFileNameWithoutExtension(targetPath);
            var existingEntry = JournalParser.ParseJournalContent(existingContent, fileStem);
            var newEntryData = JournalParser.ParseJournalContent(sanitizedContent, fileStem);
            existingEntry.MergeWith(newEntryData);
            finalContent = existingEntry.ToMarkdown();
        }
        else
        {
            finalContent = sanitizedContent;
        }

        _repo.WriteFile(targetPath, finalContent);
        return new EntrySaveResult(targetPath);
    }

    private string ResolveTargetPath(string? filePath, string defaultDataDirectory)
    {
        if (!string.IsNullOrWhiteSpace(filePath))
            return _repo.GetFullPath(filePath);

        return _repo.GetFullPath(Path.Combine(defaultDataDirectory, $"{DateTime.Now:yyyy-MM-dd}.md"));
    }
}