using LiteCharms.Features.MidrandBooks.Abstractions;
using LiteCharms.Features.MidrandBooks.Extensions;
using LiteCharms.Features.MidrandBooks.Pages.Models;
using LiteCharms.Features.MidrandBooks.Postgres;

namespace LiteCharms.Features.MidrandBooks.Pages;

public class PageService(IDbContextFactory<MidrandBooksDbContext> contextFactory) : IService
{
    public async ValueTask<Result> DeleteAllAsync(long authorBookId, CancellationToken cancellationToken = default)
    {
        try
        {
            await using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            if (!await context.Books.AnyAsync(b => b.Id == authorBookId, cancellationToken))
                return Result.Fail("Book not found");

            var pages = await context.Pages.Where(p => p.AuthorBookId == authorBookId).ToListAsync(cancellationToken);

            if (pages.Count == 0)
                return Result.Fail("No pages found for the specified book");

            context.Pages.RemoveRange(pages);

            await context.SaveChangesAsync(cancellationToken);

            return Result.Ok();
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result> DeleteByPageTypeAsync(long authorBookId, int pageNumber, BookPageTypes pageType, CancellationToken cancellationToken = default)
    {
        try
        {
            await using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var page = await context.Pages.FirstOrDefaultAsync(p => p.AuthorBookId == authorBookId && p.Number == pageNumber && p.Type == pageType, cancellationToken);

            if (page is null)
                return Result.Fail("Page not found");

            context.Pages.Remove(page);

            return await context.SaveChangesAsync(cancellationToken) > 0
                ? Result.Ok()
                : Result.Fail("Failed to delete page");
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result> UpdatePageStatusAsync(long bookPageId, bool enabled, CancellationToken cancellationToken = default)
    {
        try
        {
            await using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var page = await context.Pages.FirstOrDefaultAsync(p => p.Id == bookPageId, cancellationToken);

            if (page is null)
                return Result.Fail("Page not found");

            page.UpdatedAt = DateTime.UtcNow;
            page.Enabled = enabled;

            return await context.SaveChangesAsync(cancellationToken) > 0
                ? Result.Ok()
                : Result.Fail("Failed to update page status");
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result> DeletePageAsync(long bookPageId, CancellationToken cancellationToken = default)
    {
        try
        {
            await using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var page = await context.Pages.FirstOrDefaultAsync(p => p.Id == bookPageId, cancellationToken);

            if (page is null)
                return Result.Fail("Page not found");

            context.Pages.Remove(page);

            return await context.SaveChangesAsync(cancellationToken) > 0
                ? Result.Ok()
                : Result.Fail("Failed to delete page");
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result> UpdatePageAsync(long bookPageId, UpdateBookPage request, CancellationToken cancellationToken = default)
    {
        try
        {
            await using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var page = await context.Pages.FirstOrDefaultAsync(p => p.Id == bookPageId, cancellationToken);

            if (page is null)
                return Result.Fail("Page not found");
            
            page.UpdatedAt = DateTime.UtcNow;
            page.Type = request.Type;
            page.ContentType = request.ContentType;
            page.Number = request.Number;
            page.Content = request.Content;
            page.Notes = request.Notes;
            page.References = request.References;

            return await context.SaveChangesAsync(cancellationToken) > 0
                ? Result.Ok()
                : Result.Fail("Failed to update page");
        }
        catch (Exception ex)
        {
            return Result.Fail(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result<long>> CreatePageAsync(long authorBookId, CreateBookPage request, CancellationToken cancellationToken = default)
    {
        try
        {
            await using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            if (!await context.Books.AnyAsync(b => b.Id == authorBookId, cancellationToken))
                return Result.Fail<long>("Book not found");

            if (await context.Pages.AnyAsync(p => p.AuthorBookId == authorBookId && p.Number == request.Number && p.Type == request.Type, cancellationToken))
                return Result.Fail<long>("A page with the same number already exists for this book");

            var page = context.Pages.Add(new Entities.BookPage
            {
                AuthorBookId = authorBookId,
                Type = request.Type,
                ContentType = request.ContentType,
                Number = request.Number,
                Content = request.Content,
                Notes = request.Notes,
                References = request.References,
                Enabled = true
            });

            return await context.SaveChangesAsync(cancellationToken) > 0
                ? Result.Ok(page.Entity.Id)
                : Result.Fail<long>("Failed to create page");
        }
        catch (Exception ex)
        {
            return Result.Fail<long>(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result<BookPage[]>> GetPagesAsync(long authorBookId, CancellationToken cancellationToken = default)
    {
        try
        {
            await using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            if (!await context.Books.AnyAsync(b => b.Id == authorBookId, cancellationToken))
                return Result.Fail<BookPage[]>("Book not found");

            var pages = await context.Pages.AsNoTracking()
                .Where(p => p.AuthorBookId == authorBookId).ToArrayAsync(cancellationToken);

            return pages?.Length > 0
                ? Result.Ok(pages.Select(p => p.ToModel()).ToArray())
                : Result.Fail<BookPage[]>("No pages found for the specified book");
        }
        catch (Exception ex)
        {
            return Result.Fail<BookPage[]>(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result<BookPage>> GetPageByNumberAsync(long pageId, int number, CancellationToken cancellationToken = default)
    {
        try
        {
            await using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var page = await context.Pages.FirstOrDefaultAsync(p => p.Id == pageId && p.Number == number, cancellationToken);

            return page is not null
                ? page.ToModel()
                : Result.Fail<BookPage>("Page not found");
        }
        catch (Exception ex)
        {
            return Result.Fail<BookPage>(new Error(ex.Message).CausedBy(ex));
        }
    }

    public async ValueTask<Result<BookPage>> GetPageAsync(long pageId, CancellationToken cancellationToken = default)
    {
        try
        {
            await using var context = await contextFactory.CreateDbContextAsync(cancellationToken);

            var page = await context.Pages.FirstOrDefaultAsync(p => p.Id == pageId, cancellationToken);

            return page is not null
                ? page.ToModel()
                : Result.Fail<BookPage>("Page not found");
        }
        catch (Exception ex)
        {
            return Result.Fail<BookPage>(new Error(ex.Message).CausedBy(ex));
        }
    }
}