using System.Security.Claims;
using HelpDesk.Data.Repositories;
using HelpDesk.Models.DTOs;
using HelpDesk.Models.Entities;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;

namespace HelpDesk.API.Controllers;

[ApiController]
[Route("api/kb")]
[Authorize]
public class KnowledgeBaseController : ControllerBase
{
    private readonly IKnowledgeBaseRepository _kbRepository;

    public KnowledgeBaseController(IKnowledgeBaseRepository kbRepository)
    {
        _kbRepository = kbRepository;
    }

    // ===== Articles =====

    [HttpGet("articles")]
    [Authorize(Policy = "Agent")]
    public async Task<ActionResult<IEnumerable<ArticleDto>>> GetAllArticles()
    {
        var articles = await _kbRepository.GetAllArticlesAsync();
        return Ok(articles.Select(MapArticleToDto));
    }

    [HttpGet("articles/published")]
    [AllowAnonymous]
    public async Task<ActionResult<IEnumerable<ArticleDto>>> GetPublishedArticles()
    {
        var articles = await _kbRepository.GetPublishedArticlesAsync();
        return Ok(articles.Select(MapArticleToDto));
    }

    [HttpGet("search")]
    [AllowAnonymous]
    public async Task<ActionResult<IEnumerable<ArticleDto>>> SearchArticles([FromQuery] string q)
    {
        if (string.IsNullOrWhiteSpace(q))
            return BadRequest(new { error = "Search query is required." });

        var articles = await _kbRepository.SearchArticlesAsync(q);
        return Ok(articles.Select(MapArticleToDto));
    }

    [HttpGet("articles/{id}")]
    public async Task<ActionResult<ArticleDto>> GetArticle(Guid id)
    {
        var article = await _kbRepository.GetArticleByIdAsync(id);
        if (article == null) return NotFound(new { error = "Article not found." });
        return Ok(MapArticleToDto(article));
    }

    [HttpPost("articles")]
    [Authorize(Policy = "Agent")]
    public async Task<ActionResult<ArticleDto>> CreateArticle([FromBody] CreateArticleRequest request)
    {
        if (string.IsNullOrWhiteSpace(request.Title))
            return BadRequest(new { error = "Title is required." });
        if (string.IsNullOrWhiteSpace(request.Content))
            return BadRequest(new { error = "Content is required." });

        var userId = GetUserId();
        if (userId == null) return Unauthorized();

        var article = new KnowledgeBaseArticle
        {
            Title = request.Title,
            Content = request.Content,
            CategoryId = request.CategoryId,
            IsPublished = request.IsPublished,
            AuthorId = userId.Value,
            CreatedAt = DateTime.UtcNow
        };

        var created = await _kbRepository.CreateArticleAsync(article);
        var full = await _kbRepository.GetArticleByIdAsync(created.Id);
        return CreatedAtAction(nameof(GetArticle), new { id = created.Id }, MapArticleToDto(full!));
    }

    [HttpPut("articles/{id}")]
    [Authorize(Policy = "Agent")]
    public async Task<ActionResult<ArticleDto>> UpdateArticle(Guid id, [FromBody] UpdateArticleRequest request)
    {
        var article = await _kbRepository.GetArticleByIdAsync(id);
        if (article == null) return NotFound(new { error = "Article not found." });

        if (request.Title != null) article.Title = request.Title;
        if (request.Content != null) article.Content = request.Content;
        if (request.CategoryId.HasValue) article.CategoryId = request.CategoryId.Value;
        if (request.IsPublished.HasValue) article.IsPublished = request.IsPublished.Value;

        var updated = await _kbRepository.UpdateArticleAsync(article);
        if (updated == null) return StatusCode(500, new { error = "Failed to update article." });

        var full = await _kbRepository.GetArticleByIdAsync(id);
        return Ok(MapArticleToDto(full!));
    }

    [HttpDelete("articles/{id}")]
    [Authorize(Policy = "Admin")]
    public async Task<IActionResult> DeleteArticle(Guid id)
    {
        var deleted = await _kbRepository.DeleteArticleAsync(id);
        if (!deleted) return NotFound(new { error = "Article not found." });
        return NoContent();
    }

    // ===== Categories =====

    [HttpGet("categories")]
    public async Task<ActionResult<IEnumerable<CategoryDto>>> GetCategories()
    {
        var categories = await _kbRepository.GetAllCategoriesAsync();
        return Ok(categories.Select(MapCategoryToDto));
    }

    [HttpGet("categories/{id}")]
    public async Task<ActionResult<CategoryDto>> GetCategory(Guid id)
    {
        var category = await _kbRepository.GetCategoryByIdAsync(id);
        if (category == null) return NotFound(new { error = "Category not found." });
        return Ok(MapCategoryToDto(category));
    }

    [HttpPost("categories")]
    [Authorize(Policy = "Admin")]
    public async Task<ActionResult<CategoryDto>> CreateCategory([FromBody] CreateCategoryRequest request)
    {
        if (string.IsNullOrWhiteSpace(request.Name))
            return BadRequest(new { error = "Name is required." });

        var category = new KnowledgeBaseCategory
        {
            Name = request.Name,
            Description = request.Description,
            SortOrder = request.SortOrder,
            CreatedAt = DateTime.UtcNow
        };

        var created = await _kbRepository.CreateCategoryAsync(category);
        return CreatedAtAction(nameof(GetCategory), new { id = created.Id }, MapCategoryToDto(created));
    }

    [HttpPut("categories/{id}")]
    [Authorize(Policy = "Admin")]
    public async Task<ActionResult<CategoryDto>> UpdateCategory(Guid id, [FromBody] CreateCategoryRequest request)
    {
        var category = await _kbRepository.GetCategoryByIdAsync(id);
        if (category == null) return NotFound(new { error = "Category not found." });

        category.Name = request.Name;
        category.Description = request.Description;
        category.SortOrder = request.SortOrder;

        var updated = await _kbRepository.UpdateCategoryAsync(category);
        if (updated == null) return StatusCode(500, new { error = "Failed to update category." });

        return Ok(MapCategoryToDto(updated));
    }

    [HttpDelete("categories/{id}")]
    [Authorize(Policy = "Admin")]
    public async Task<IActionResult> DeleteCategory(Guid id)
    {
        var deleted = await _kbRepository.DeleteCategoryAsync(id);
        if (!deleted) return NotFound(new { error = "Category not found." });
        return NoContent();
    }

    private Guid? GetUserId()
    {
        var claim = User.FindFirst("userId") ?? User.FindFirst(ClaimTypes.NameIdentifier);
        return claim != null && Guid.TryParse(claim.Value, out var id) ? id : null;
    }

    private static ArticleDto MapArticleToDto(KnowledgeBaseArticle a) => new()
    {
        Id = a.Id,
        Title = a.Title,
        Content = a.Content,
        IsPublished = a.IsPublished,
        CategoryId = a.CategoryId,
        CategoryName = a.Category?.Name ?? "Unknown",
        AuthorId = a.AuthorId,
        AuthorName = a.Author != null ? $"{a.Author.FirstName} {a.Author.LastName}" : "Unknown",
        ViewCount = a.ViewCount,
        CreatedAt = a.CreatedAt,
        UpdatedAt = a.UpdatedAt
    };

    private static CategoryDto MapCategoryToDto(KnowledgeBaseCategory c) => new()
    {
        Id = c.Id,
        Name = c.Name,
        Description = c.Description,
        SortOrder = c.SortOrder,
        ArticleCount = c.Articles?.Count ?? 0,
        CreatedAt = c.CreatedAt
    };
}