using System.Diagnostics;
using LiteDB.Async;
using Microsoft.Extensions.Options;
using Octokit;
using StabilityMatrix.Core.Extensions;
using StabilityMatrix.Core.Models.Api;
using StabilityMatrix.Core.Models.Configs;
using StabilityMatrix.Core.Models.Database;
using StabilityMatrix.Core.Services;

namespace StabilityMatrix.Core.Database;

public class LiteDbContext : ILiteDbContext
{
    private readonly ISettingsManager settingsManager;
    private readonly DebugOptions debugOptions;

    private LiteDatabaseAsync? database;
    public LiteDatabaseAsync Database
    {
        get
        {
            if (database is null) throw new InvalidOperationException("Database not set before access");
            return database;
        }
        private set
        {
            database?.Dispose();
            database = value;
        }
    }

    // Notification events
    public event EventHandler? CivitModelsChanged;
    
    // Collections (Tables)
    public ILiteCollectionAsync<CivitModel> CivitModels => Database.GetCollection<CivitModel>("CivitModels");
    public ILiteCollectionAsync<CivitModelVersion> CivitModelVersions => Database.GetCollection<CivitModelVersion>("CivitModelVersions");
    public ILiteCollectionAsync<CivitModelQueryCacheEntry> CivitModelQueryCache => Database.GetCollection<CivitModelQueryCacheEntry>("CivitModelQueryCache");
    public ILiteCollectionAsync<GithubCacheEntry> GithubCache => Database.GetCollection<GithubCacheEntry>("GithubCache");
    
    public LiteDbContext(ISettingsManager settingsManager, IOptions<DebugOptions> debugOptions)
    {
        this.settingsManager = settingsManager;
        this.debugOptions = debugOptions.Value;
        
        var connectionString = debugOptions.Value.TempDatabase ? ":temp:"
            : $"Filename={Path.Combine(settingsManager.LibraryDir, "StabilityMatrix.db")};Mode=Shared";
        Database = new LiteDatabaseAsync(connectionString);

        // Register reference fields
        LiteDBExtensions.Register<CivitModel, CivitModelVersion>(m => m.ModelVersions, "CivitModelVersions");
        LiteDBExtensions.Register<CivitModelQueryCacheEntry, CivitModel>(e => e.Items, "CivitModels");
    }
    
    public async Task<(CivitModel?, CivitModelVersion?)> FindCivitModelFromFileHashAsync(string hashBlake3)
    {
        var version = await CivitModelVersions.Query()
            .Where(mv => mv.Files!
                .Select(f => f.Hashes)
                .Select(hashes => hashes.BLAKE3)
                .Any(hash => hash == hashBlake3))
            .FirstOrDefaultAsync();
        if (version is null) return (null, null);
        var model = await CivitModels.Query()
            .Include(m => m.ModelVersions)
            .Where(m => m.ModelVersions!
                .Select(v => v.Id)
                .Any(id => id == version.Id))
            .FirstOrDefaultAsync();
        return (model, version);
    }
    
    public async Task<bool> UpsertCivitModelAsync(CivitModel civitModel)
    {
        // Insert model versions first then model
        var versionsUpdated = await CivitModelVersions.UpsertAsync(civitModel.ModelVersions);
        var updated = await CivitModels.UpsertAsync(civitModel);
        // Notify listeners on any change
        var anyUpdated = versionsUpdated > 0 || updated;
        if (anyUpdated)
        {
            CivitModelsChanged?.Invoke(this, EventArgs.Empty);
        }
        return anyUpdated;
    }
    
    public async Task<bool> UpsertCivitModelAsync(IEnumerable<CivitModel> civitModels)
    {
        var civitModelsArray = civitModels.ToArray();
        // Get all model versions then insert models
        var versions = civitModelsArray.SelectMany(model => model.ModelVersions ?? new());
        var versionsUpdated = await CivitModelVersions.UpsertAsync(versions);
        var updated = await CivitModels.UpsertAsync(civitModelsArray);
        // Notify listeners on any change
        var anyUpdated = versionsUpdated > 0 || updated > 0;
        if (updated > 0 || versionsUpdated > 0)
        {
            CivitModelsChanged?.Invoke(this, EventArgs.Empty);
        }
        return anyUpdated;
    }
    
    // Add to cache
    public async Task<bool> UpsertCivitModelQueryCacheEntryAsync(CivitModelQueryCacheEntry entry)
    {
        var changed = await CivitModelQueryCache.UpsertAsync(entry);
        if (changed)
        {
            CivitModelsChanged?.Invoke(this, EventArgs.Empty);
        }

        return changed;
    }

    public Task<GithubCacheEntry?> GetGithubCacheEntry(string cacheKey) =>
        GithubCache.FindByIdAsync(cacheKey);

    public Task<bool> UpsertGithubCacheEntry(GithubCacheEntry cacheEntry) =>
        GithubCache.UpsertAsync(cacheEntry);

    public void Dispose()
    {
        database?.UnderlyingDatabase.Dispose();
        database?.Dispose();
        GC.SuppressFinalize(this);
    }
}