using System;
using System.Security.Claims;
using System.Threading.Tasks;
using FinlyticBackend.Database;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Cors;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;

namespace FinlyticBackend.Controllers;

[ApiController]
[Route("api/v1/user/preferences")]
[Authorize]
public class UserPreferencesController : ControllerBase
{
    private readonly BackendDbContext _context;

    public UserPreferencesController(BackendDbContext context)
    {
        _context = context;
    }

    /// <summary>
    /// Request payload for updating the user's theme.
    /// Supported IDs for FluentAvalonia: fluent_dark, fluent_light, fluent_accent, dark_classic.
    /// </summary>
    public record UpdateThemeRequest(string ThemeId);

    /// <summary>
    /// Gets current user preferences including FluentAvalonia theme preference.
    /// </summary>
    [HttpGet]
    public async Task<IActionResult> GetPreferences()
    {
        var userIdStr = User.FindFirstValue(ClaimTypes.NameIdentifier) ?? User.FindFirstValue("sub");
        if (!Guid.TryParse(userIdStr, out var userId))
        {
            return Unauthorized(new { message = "Invalid user claims." });
        }

        var user = await _context.Users.AsNoTracking().FirstOrDefaultAsync(u => u.Id == userId);
        if (user == null)
        {
            return NotFound(new { message = "User not found." });
        }

        // Default logic for FluentAvaloniaTheme integration
        string theme = string.IsNullOrWhiteSpace(user.ThemePreference) ? "fluent_dark" : user.ThemePreference;

        return Ok(new
        {
            userId = user.Id,
            email = user.Email,
            fullName = user.FullName,
            role = user.Role,
            themePreference = theme
        });
    }

    /// <summary>
    /// Updates current user theme preference in PostgreSQL database.
    /// </summary>
    [HttpPut("theme")]
    public async Task<IActionResult> UpdateThemePreference([FromBody] UpdateThemeRequest request)
    {
        if (request == null || string.IsNullOrWhiteSpace(request.ThemeId))
        {
            return BadRequest(new { message = "ThemeId is required." });
        }

        var userIdStr = User.FindFirstValue(ClaimTypes.NameIdentifier) ?? User.FindFirstValue("sub");
        if (!Guid.TryParse(userIdStr, out var userId))
        {
            return Unauthorized(new { message = "Invalid user claims." });
        }

        var user = await _context.Users.FirstOrDefaultAsync(u => u.Id == userId);
        if (user == null)
        {
            return NotFound(new { message = "User not found." });
        }

        string cleanTheme = request.ThemeId.Trim().ToLowerInvariant();
        
        // Normalize theme names for FluentAvaloniaTheme support
        user.ThemePreference = cleanTheme switch
        {
            "dark" => "fluent_dark",
            "light" => "fluent_light",
            _ => cleanTheme
        };

        await _context.SaveChangesAsync();

        return Ok(new
        {
            message = "Theme preference updated successfully.",
            themePreference = user.ThemePreference
        });
    }
}