using System.Text;
using System.Text.Json;
using SharepointToolbox.Web.Core.Models;

namespace SharepointToolbox.Web.Infrastructure.Persistence;

public class TemplateRepository
{
    private readonly string _directory;
    private readonly SemaphoreSlim _lock = new(1, 1);

    public TemplateRepository(string directory) { _directory = directory; }

    public async Task<IReadOnlyList<SiteTemplate>> GetAllAsync()
    {
        if (!Directory.Exists(_directory)) return Array.Empty<SiteTemplate>();
        var files = Directory.GetFiles(_directory, "*.json");
        var templates = new List<SiteTemplate>();
        foreach (var file in files)
        {
            try
            {
                var json = await File.ReadAllTextAsync(file, Encoding.UTF8);
                var t = JsonSerializer.Deserialize<SiteTemplate>(json,
                    new JsonSerializerOptions { PropertyNameCaseInsensitive = true });
                if (t is not null) templates.Add(t);
            }
            catch { /* skip corrupt files */ }
        }
        return templates.OrderByDescending(t => t.CapturedAt).ToList();
    }

    public async Task<SiteTemplate?> GetByIdAsync(string id)
    {
        var file = Path.Combine(_directory, $"{id}.json");
        if (!File.Exists(file)) return null;
        try
        {
            var json = await File.ReadAllTextAsync(file, Encoding.UTF8);
            return JsonSerializer.Deserialize<SiteTemplate>(json,
                new JsonSerializerOptions { PropertyNameCaseInsensitive = true });
        }
        catch { return null; }
    }

    public async Task SaveAsync(SiteTemplate template)
    {
        await _lock.WaitAsync();
        try
        {
            Directory.CreateDirectory(_directory);
            var json = JsonSerializer.Serialize(template, new JsonSerializerOptions
            {
                WriteIndented = true, PropertyNamingPolicy = JsonNamingPolicy.CamelCase
            });
            var path = Path.Combine(_directory, $"{template.Id}.json");
            var tmp = path + ".tmp";
            await File.WriteAllTextAsync(tmp, json, Encoding.UTF8);
            File.Move(tmp, path, overwrite: true);
        }
        finally { _lock.Release(); }
    }

    public Task DeleteAsync(string id)
    {
        var file = Path.Combine(_directory, $"{id}.json");
        if (File.Exists(file)) File.Delete(file);
        return Task.CompletedTask;
    }

    public async Task RenameAsync(string id, string newName)
    {
        var t = await GetByIdAsync(id);
        if (t is null) return;
        t.Name = newName;
        await SaveAsync(t);
    }
}