using LiteCharms.Features.MidrandBooks.Categories;
using LiteCharms.Features.MidrandBooks.Products;

namespace LiteCharms.Features.MidrandBooks.Seed;

public sealed class CategorySeederService(CategoryService categoryService, ProductService productService, IFeatureManager features,
    ILogger<CategorySeederService> logger) : BackgroundService
{
    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
    {
        if (!await features.IsEnabledAsync("CategorySeederService")) return;

        logger.LogInformation("Category and Product-Tag Mapping Seeding started (15-char limit applied)");

        // Initialize Bogus to ensure repeatable distribution matrix pathing
        var faker = new Faker();
        Randomizer.Seed = new Random(101);

        // 1. Curate Broad Book Categories (IsMain = true, Max 20, Max 15 chars)
        var broadMainCategories = new[]
        {
            "Fiction", "Non-Fiction", "Youth & Kids", "Academic",
            "Biographies", "Business", "Sci-Fi & Fantasy",
            "Thrillers", "Self-Help", "History",
            "Spirituality", "Arts & Photo", "Technology",
            "Cookbooks", "Travel & Maps", "Poetry & Drama", "Graphic Novels"
        };

        // 2. Curate Niche Subcategories/Tags (IsMain = false, Max 15 chars)
        var specializedSubCategories = new[]
        {
            "Cyberpunk", "Space Opera", "Historical Fix", "Cozy Mystery", "True Crime",
            "Agile Project", "Software Eng", "AI & ML", "Cloud Comput",
            "SA History", "African Lit", "Apartheid Era", "Mandela Legacy",
            "Finance", "Investments", "Startup", "Leadership",
            "CBT Therapy", "Mindfulness", "Yoga & Health",
            "Baking Basics", "African Food", "Vegan Recipes",
            "Ancient World", "WWII History", "Geopolitics",
            "Writing Guides", "Criticism", "Classic Poetry",
            "Early Learning", "Teen Romance", "Survival",
            "Urban Fantasy", "Dark Fantasy", "Psych Thriller", "Hard Sci-Fi",
            "Data Science", "DevOps", "Cybersecurity",
            "Economics", "Real Estate", "Governance",
            "Essays", "Memoirs", "Art History",
            "Architecture", "Photography", "Travel Writing",
            "Gaming Culture", "Philosophy", "Ethics",
            "DIY Home", "SA Gardening", "Parenting"
        };

        // 3. Seed Main Categories into the System
        logger.LogInformation("Seeding broad main categories...");
        foreach (var mainCat in broadMainCategories)
        {
            if (stoppingToken.IsCancellationRequested) return;

            // Defensive truncation fallback just in case strings get modified later
            string safeName = mainCat.Length > 15 ? mainCat.Substring(0, 15) : mainCat;

            var result = await categoryService.CreateCategoryAsync(safeName, isMain: true, stoppingToken);
            if (result.IsFailed && !result.Errors[0].Message.Contains("already exists", StringComparison.OrdinalIgnoreCase))
            {
                logger.LogWarning("Notice while adding main category '{Name}': {Msg}", safeName, result.Errors[0].Message);
            }
        }

        // 4. Seed Subcategories into the System
        logger.LogInformation("Seeding boundless specialized niche tags...");
        foreach (var subCat in specializedSubCategories)
        {
            if (stoppingToken.IsCancellationRequested) return;

            string safeName = subCat.Length > 15 ? subCat.Substring(0, 15) : subCat;

            var result = await categoryService.CreateCategoryAsync(safeName, isMain: false, stoppingToken);
            if (result.IsFailed && !result.Errors[0].Message.Contains("already exists", StringComparison.OrdinalIgnoreCase))
            {
                logger.LogWarning("Notice while adding subcategory '{Name}': {Msg}", safeName, result.Errors[0].Message);
            }
        }

        // 5. Query back all enabled categories to extract active IDs for junction mapping
        var fetchMainResult = await categoryService.GetCategoriesAsync(isMain: true, stoppingToken);
        var fetchSubResult = await categoryService.GetCategoriesAsync(isMain: false, stoppingToken);

        if (fetchMainResult.IsFailed || fetchSubResult.IsFailed)
        {
            logger.LogError("Aborting junction seeding: Could not retrieve categories from data store.");
            return;
        }

        var mainCategoryIds = fetchMainResult.Value.Select(c => c.Id).ToArray();
        var subCategoryIds = fetchSubResult.Value.Select(c => c.Id).ToArray();

        // 6. Map Categories to your Product Collection (Product IDs 0 - 21)
        logger.LogInformation("Beginning Product-Category mapping assignments for Product IDs 0 through 21...");

        for (long productId = 0; productId <= 21; productId++)
        {
            if (stoppingToken.IsCancellationRequested) break;

            // Every book belongs to 1 or 2 main categories
            int mainCategoriesToAssign = faker.Random.Number(1, 2);
            var chosenMainIds = faker.PickRandom(mainCategoryIds, mainCategoriesToAssign).Distinct();

            foreach (var mainId in chosenMainIds)
            {
                var linkResult = await productService.AddProductCategoryAsync(productId, mainId, stoppingToken);
                if (linkResult.IsFailed)
                {
                    if (!linkResult.Errors[0].Message.Contains("exist", StringComparison.OrdinalIgnoreCase))
                    {
                        logger.LogDebug("Junction note for Product {PId} and Main Category {CId}: {Msg}", productId, mainId, linkResult.Errors[0].Message);
                    }
                }
            }

            // Every book gets 1 to 4 granular subgenre tags
            int subCategoriesToAssign = faker.Random.Number(1, 4);
            var chosenSubIds = faker.PickRandom(subCategoryIds, subCategoriesToAssign).Distinct();

            foreach (var subId in chosenSubIds)
            {
                var linkResult = await productService.AddProductCategoryAsync(productId, subId, stoppingToken);
                if (linkResult.IsFailed && !linkResult.Errors[0].Message.Contains("exist", StringComparison.OrdinalIgnoreCase))
                {
                    logger.LogDebug("Junction note for Product {PId} and Sub Category {CId}: {Msg}", productId, subId, linkResult.Errors[0].Message);
                }
            }
        }

        logger.LogInformation("Category and Product-Tag Mapping Seeding completed successfully.");
    }
}