#!/usr/bin/env dotnet-script
#r "nuget: MongoDB.Driver, 2.23.1"
#r "nuget: Microsoft.EntityFrameworkCore.SqlServer, 8.0.0"
#r "nuget: Microsoft.EntityFrameworkCore, 8.0.0"
#r "nuget: System.Text.Json, 8.0.0"

using MongoDB.Driver;
using MongoDB.Bson;
using Microsoft.EntityFrameworkCore;
using System.Text.Json;

Console.WriteLine("==============================================");
Console.WriteLine("MongoDB to SQL Server Migration Script");
Console.WriteLine("==============================================\n");

// Connection strings
var mongoConnectionString = "mongodb://localhost:27017";
var mongoDatabaseName = "SkyArtShopDB";
var sqlConnectionString = "Server=localhost,1433;Database=SkyArtShop;User Id=sa;Password=Str0ngP@ssw0rd!2025;TrustServerCertificate=True;";

Console.WriteLine($"MongoDB: {mongoConnectionString}/{mongoDatabaseName}");
Console.WriteLine($"SQL Server: Server=localhost,1433;Database=SkyArtShop\n");

// Connect to MongoDB
var mongoClient = new MongoClient(mongoConnectionString);
var mongoDatabase = mongoClient.GetDatabase(mongoDatabaseName);

Console.WriteLine("✓ Connected to MongoDB");

// Test SQL connection
try
{
    using (var connection = new Microsoft.Data.SqlClient.SqlConnection(sqlConnectionString))
    {
        connection.Open();
        Console.WriteLine("✓ Connected to SQL Server\n");
    }
}
catch (Exception ex)
{
    Console.WriteLine($"✗ Failed to connect to SQL Server: {ex.Message}");
    return 1;
}

Console.WriteLine("Starting data migration...\n");

// Migration statistics
int totalCollections = 0;
int totalDocuments = 0;
var errors = new List<string>();

try
{
    // Get all collections
    var collections = new[] 
    { 
        "Pages", "PortfolioCategories", "PortfolioProjects", 
        "Products", "BlogPosts", "SiteSettings", "MenuItems", 
        "AdminUsers", "UserRoles", "Orders", "ProductViews", 
        "HomepageSections" 
    };

    foreach (var collectionName in collections)
    {
        try
        {
            Console.WriteLine($"Migrating {collectionName}...");
            var collection = mongoDatabase.GetCollection<BsonDocument>(collectionName);
            var documents = await collection.Find(new BsonDocument()).ToListAsync();
            
            if (documents.Count == 0)
            {
                Console.WriteLine($"  → 0 documents (skipped)\n");
                continue;
            }

            // Export to JSON file for SQL import
            var jsonData = new List<string>();
            foreach (var doc in documents)
            {
                // Convert ObjectId to string
                if (doc.Contains("_id"))
                {
                    doc["_id"] = doc["_id"].ToString();
                }
                
                // Handle nested ObjectIds
                ConvertObjectIdsToStrings(doc);
                
                jsonData.Add(doc.ToJson(new MongoDB.Bson.IO.JsonWriterSettings { OutputMode = MongoDB.Bson.IO.JsonOutputMode.Strict }));
            }

            // Save to file
            var outputPath = $"/tmp/migration_{collectionName}.json";
            await File.WriteAllTextAsync(outputPath, $"[{string.Join(",", jsonData)}]");
            
            Console.WriteLine($"  ✓ Exported {documents.Count} documents to {outputPath}");
            totalDocuments += documents.Count;
            totalCollections++;
        }
        catch (Exception ex)
        {
            errors.Add($"{collectionName}: {ex.Message}");
            Console.WriteLine($"  ✗ Error: {ex.Message}");
        }
        
        Console.WriteLine();
    }

    Console.WriteLine("==============================================");
    Console.WriteLine("Migration Export Complete");
    Console.WriteLine("==============================================");
    Console.WriteLine($"Collections exported: {totalCollections}");
    Console.WriteLine($"Total documents: {totalDocuments}");
    
    if (errors.Count > 0)
    {
        Console.WriteLine($"\nErrors ({errors.Count}):");
        foreach (var error in errors)
        {
            Console.WriteLine($"  - {error}");
        }
    }
    
    Console.WriteLine("\n✓ JSON files created in /tmp/migration_*.json");
    Console.WriteLine("✓ Next step: Run the C# import program to load into SQL Server");
    
    return 0;
}
catch (Exception ex)
{
    Console.WriteLine($"\n✗ Fatal error: {ex.Message}");
    Console.WriteLine(ex.StackTrace);
    return 1;
}

void ConvertObjectIdsToStrings(BsonDocument doc)
{
    var keysToConvert = new List<string>();
    
    foreach (var element in doc)
    {
        if (element.Value.IsObjectId)
        {
            keysToConvert.Add(element.Name);
        }
        else if (element.Value.IsBsonDocument)
        {
            ConvertObjectIdsToStrings(element.Value.AsBsonDocument);
        }
        else if (element.Value.IsBsonArray)
        {
            foreach (var item in element.Value.AsBsonArray)
            {
                if (item.IsBsonDocument)
                {
                    ConvertObjectIdsToStrings(item.AsBsonDocument);
                }
            }
        }
    }
    
    foreach (var key in keysToConvert)
    {
        doc[key] = doc[key].ToString();
    }
}