using AutoMapper;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Options;
using PowderCoating.Application.Configuration;
using PowderCoating.Application.DTOs.BugReport;
using PowderCoating.Application.Interfaces;
using PowderCoating.Core.Entities;
using PowderCoating.Core.Enums;
using PowderCoating.Core.Interfaces;
using PowderCoating.Shared.Constants;

namespace PowderCoating.Web.Controllers;

[Authorize]
public class BugReportController : Controller
{
    private readonly IUnitOfWork _unitOfWork;
    private readonly IMapper _mapper;
    private readonly ITenantContext _tenantContext;
    private readonly UserManager<ApplicationUser> _userManager;
    private readonly IEmailService _emailService;
    private readonly IAdminNotificationService _adminNotification;
    private readonly IAzureBlobStorageService _blobService;
    private readonly StorageSettings _storageSettings;
    private readonly ILogger<BugReportController> _logger;

    private static readonly string[] AllowedMediaTypes = [
        ".jpg", ".jpeg", ".png", ".gif", ".webp",
        ".mp4", ".mov", ".avi", ".mkv", ".webm"
    ];
    private const long MaxMediaSizeBytes = 100 * 1024 * 1024; // 100 MB

    public BugReportController(
        IUnitOfWork unitOfWork,
        IMapper mapper,
        ITenantContext tenantContext,
        UserManager<ApplicationUser> userManager,
        IEmailService emailService,
        IAdminNotificationService adminNotification,
        IAzureBlobStorageService blobService,
        IOptions<StorageSettings> storageSettings,
        ILogger<BugReportController> logger)
    {
        _unitOfWork = unitOfWork;
        _mapper = mapper;
        _tenantContext = tenantContext;
        _userManager = userManager;
        _emailService = emailService;
        _adminNotification = adminNotification;
        _blobService = blobService;
        _storageSettings = storageSettings.Value;
        _logger = logger;
    }

    /// <summary>
    /// Renders the bug-report submission form for the currently authenticated user.
    /// Returns an empty <see cref="CreateBugReportDto"/> so the view has a bound model
    /// with sensible defaults (e.g. Priority pre-set to Normal).
    /// </summary>
    // GET: /BugReport/Submit
    [HttpGet]
    public IActionResult Submit()
    {
        return View(new CreateBugReportDto());
    }

    /// <summary>
    /// Accepts a bug report form submission, persists the report, uploads any media
    /// attachments to Azure Blob Storage, and notifies platform admins.
    /// <para>
    /// Design decisions:
    /// <list type="bullet">
    ///   <item>The request-size limit is set to 110 MB (slightly above the 100 MB per-file
    ///         cap) to allow multi-file payloads while still enforcing a hard ceiling.</item>
    ///   <item>The bug report record is saved to the database <em>before</em> attachment
    ///         upload so the auto-generated <c>BugReport.Id</c> is available as the blob
    ///         folder prefix: <c>{companyId}/{bugReportId}/{guid}{ext}</c>.</item>
    ///   <item>Individual upload failures are logged as warnings but do not abort the
    ///         overall submission — a partial upload is still a valid report.</item>
    ///   <item>Attachments are tracked in <c>BugReportAttachment</c> rows via the raw
    ///         <c>ApplicationDbContext</c> (not IUnitOfWork) because they need a
    ///         separate <c>SaveChangesAsync()</c> call after all blobs are uploaded.</item>
    /// </list>
    /// </para>
    /// </summary>
    // POST: /BugReport/Submit
    [HttpPost]
    [ValidateAntiForgeryToken]
    [RequestSizeLimit(110 * 1024 * 1024)]
    public async Task<IActionResult> Submit(CreateBugReportDto dto, List<IFormFile>? attachments)
    {
        if (!ModelState.IsValid)
            return View(dto);

        try
        {
            var companyId = _tenantContext.GetCurrentCompanyId();
            if (companyId == null)
            {
                TempData["ErrorMessage"] = "Your account is not associated with a company. Please contact support.";
                return RedirectToAction("Index", "Home");
            }

            var user = await _userManager.GetUserAsync(User);
            var userName = user != null ? user.FullName : User.Identity?.Name ?? "Unknown";

            // Resolve company name
            var company = await _unitOfWork.Companies.GetByIdAsync(companyId.Value);
            var companyName = company?.CompanyName ?? $"Company #{companyId}";

            var bugReport = _mapper.Map<BugReport>(dto);
            bugReport.CompanyId = companyId.Value;
            bugReport.CompanyName = companyName;
            bugReport.SubmittedByUserId = user?.Id ?? string.Empty;
            bugReport.SubmittedByUserName = userName;
            bugReport.Status = BugReportStatus.New;

            await _unitOfWork.BugReports.AddAsync(bugReport);
            await _unitOfWork.CompleteAsync();

            // Upload attachments
            var uploadedCount = 0;
            if (attachments != null && attachments.Count > 0)
            {
                foreach (var file in attachments)
                {
                    if (file == null || file.Length == 0) continue;
                    if (file.Length > MaxMediaSizeBytes) continue;

                    var ext = Path.GetExtension(file.FileName).ToLowerInvariant();
                    if (!AllowedMediaTypes.Contains(ext)) continue;

                    var blobPath = $"{companyId}/{bugReport.Id}/{Guid.NewGuid():N}{ext}";
                    using var stream = file.OpenReadStream();
                    var result = await _blobService.UploadAsync(
                        _storageSettings.Containers.BugReportMedia, blobPath, stream, file.ContentType);

                    if (result.Success)
                    {
                        var attachment = new BugReportAttachment
                        {
                            BugReportId = bugReport.Id,
                            CompanyId = companyId.Value,
                            BlobPath = blobPath,
                            FileName = file.FileName,
                            ContentType = file.ContentType,
                            FileSizeBytes = file.Length
                        };
                        await _unitOfWork.BugReportAttachments.AddAsync(attachment);
                        uploadedCount++;
                    }
                    else
                    {
                        _logger.LogWarning("Failed to upload bug report attachment {FileName}: {Error}",
                            file.FileName, result.ErrorMessage);
                    }
                }

                if (uploadedCount > 0)
                    await _unitOfWork.CompleteAsync();
            }

            _logger.LogInformation("Bug report #{Id} submitted by {UserName} ({Company}): {Title} with {AttachmentCount} attachment(s)",
                bugReport.Id, userName, companyName, dto.Title, uploadedCount);

            await _adminNotification.NotifyBugReportSubmittedAsync(
                bugReport.Id, dto.Title, dto.Description,
                dto.Priority.ToString(), userName, companyName);

            TempData["SuccessMessage"] = "Your bug report has been submitted. Thank you for helping us improve!";
            return RedirectToAction(nameof(Submit));
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error submitting bug report");
            TempData["ErrorMessage"] = "An error occurred while submitting your report. Please try again.";
            return View(dto);
        }
    }

    /// <summary>
    /// Displays a paginated, filterable list of all bug reports across every tenant
    /// (SuperAdmin only).
    /// <para>
    /// Uses <c>IgnoreQueryFilters()</c> to bypass the global soft-delete and
    /// multi-tenancy filters so SuperAdmins see reports from all companies.
    /// The manual <c>!r.IsDeleted</c> predicate is intentionally re-added so that
    /// physically deleted records (which should be rare) are still excluded.
    /// Sorting is resolved with a switch expression covering the five UI columns;
    /// any unrecognised column falls back to descending <c>CreatedAt</c>.
    /// </para>
    /// </summary>
    // GET: /BugReport/Index — SuperAdmin only
    [Authorize(Policy = AppConstants.Policies.SuperAdminOnly)]
    public async Task<IActionResult> Index(
        string? searchTerm,
        string? statusFilter,
        string? priorityFilter,
        string sortColumn = "CreatedAt",
        string sortDirection = "desc",
        int pageNumber = 1,
        int pageSize = 25)
    {
        pageNumber = Math.Max(1, pageNumber);
        pageSize = pageSize is 10 or 25 or 50 or 100 ? pageSize : 25;

        var allReports = (await _unitOfWork.BugReports.GetAllAsync(ignoreQueryFilters: true))
            .AsEnumerable();

        if (!string.IsNullOrWhiteSpace(searchTerm))
        {
            var search = searchTerm.ToLower();
            allReports = allReports.Where(r =>
                r.Title.ToLower().Contains(search) ||
                r.Description.ToLower().Contains(search) ||
                r.SubmittedByUserName.ToLower().Contains(search));
        }

        if (!string.IsNullOrWhiteSpace(statusFilter) &&
            Enum.TryParse<BugReportStatus>(statusFilter, out var status))
            allReports = allReports.Where(r => r.Status == status);

        if (!string.IsNullOrWhiteSpace(priorityFilter) &&
            Enum.TryParse<BugReportPriority>(priorityFilter, out var priority))
            allReports = allReports.Where(r => r.Priority == priority);

        allReports = (sortColumn, sortDirection == "asc") switch
        {
            ("Title", true)      => allReports.OrderBy(r => r.Title),
            ("Title", false)     => allReports.OrderByDescending(r => r.Title),
            ("Status", true)     => allReports.OrderBy(r => r.Status),
            ("Status", false)    => allReports.OrderByDescending(r => r.Status),
            ("Priority", true)   => allReports.OrderBy(r => r.Priority),
            ("Priority", false)  => allReports.OrderByDescending(r => r.Priority),
            ("Submitted", true)  => allReports.OrderBy(r => r.SubmittedByUserName),
            ("Submitted", false) => allReports.OrderByDescending(r => r.SubmittedByUserName),
            (_, true)            => allReports.OrderBy(r => r.CreatedAt),
            _                    => allReports.OrderByDescending(r => r.CreatedAt)
        };

        var totalCount = allReports.Count();
        var items = allReports
            .Skip((pageNumber - 1) * pageSize)
            .Take(pageSize)
            .ToList();

        var dtos = _mapper.Map<List<BugReportDto>>(items);

        ViewBag.SearchTerm = searchTerm;
        ViewBag.StatusFilter = statusFilter;
        ViewBag.PriorityFilter = priorityFilter;
        ViewBag.SortColumn = sortColumn;
        ViewBag.SortDirection = sortDirection;
        ViewBag.TotalCount = totalCount;
        ViewBag.PageNumber = pageNumber;
        ViewBag.PageSize = pageSize;
        ViewBag.TotalPages = (int)Math.Ceiling(totalCount / (double)pageSize);

        return View(dtos);
    }

    /// <summary>
    /// Loads a bug report and its attachments for editing by a SuperAdmin.
    /// <para>
    /// Both the report and its attachment rows are fetched with
    /// <c>IgnoreQueryFilters()</c> because SuperAdmins need visibility into
    /// cross-tenant records. The explicit <c>IsDeleted</c> guard prevents
    /// editing a report that has been soft-deleted.
    /// Attachments are loaded separately (not via EF navigation) so they can be
    /// displayed in the Edit view without requiring a full Include chain.
    /// </para>
    /// </summary>
    // GET: /BugReport/Edit/5 — SuperAdmin only
    [Authorize(Policy = AppConstants.Policies.SuperAdminOnly)]
    [HttpGet]
    public async Task<IActionResult> Edit(int id)
    {
        var bugReport = await _unitOfWork.BugReports.GetByIdAsync(id, ignoreQueryFilters: true);
        if (bugReport == null || bugReport.IsDeleted)
            return NotFound();

        var dto = _mapper.Map<EditBugReportDto>(bugReport);

        var attachments = (await _unitOfWork.BugReportAttachments.FindAsync(
                a => a.BugReportId == id && !a.IsDeleted, ignoreQueryFilters: true))
            .OrderBy(a => a.CreatedAt)
            .ToList();

        dto.Attachments = _mapper.Map<List<BugReportAttachmentDto>>(attachments);

        return View(dto);
    }

    /// <summary>
    /// Streams a bug-report attachment from Azure Blob Storage directly to the browser.
    /// Returns a <c>FileResult</c> with the original filename and content-type so the
    /// browser can render images inline or prompt a download for other media types.
    /// <para>
    /// Access is restricted to SuperAdmin because attachment blobs are stored outside
    /// the tenant-scoped container and could contain sensitive reproduction screenshots.
    /// The blob path is resolved from the <c>BugReportAttachment</c> record (not from a
    /// user-supplied path) to prevent path-traversal attacks.
    /// </para>
    /// </summary>
    // GET: /BugReport/Attachment/5 — SuperAdmin only — streams blob to browser
    [Authorize(Policy = AppConstants.Policies.SuperAdminOnly)]
    [HttpGet]
    public async Task<IActionResult> Attachment(int id)
    {
        var attachment = await _unitOfWork.BugReportAttachments.GetByIdAsync(id, ignoreQueryFilters: true);

        if (attachment == null)
            return NotFound();

        var download = await _blobService.DownloadAsync(
            _storageSettings.Containers.BugReportMedia, attachment.BlobPath);

        if (!download.Success)
            return NotFound();

        return File(download.Content, download.ContentType, attachment.FileName);
    }

    /// <summary>
    /// Persists status/priority/resolution edits to a bug report and, when the report
    /// transitions to <see cref="BugReportStatus.Completed"/> for the first time,
    /// emails the original submitter with the resolution notes.
    /// <para>
    /// Key business rules:
    /// <list type="bullet">
    ///   <item><c>ResolvedAt</c> / <c>ResolvedBy</c> are stamped only on the first
    ///         transition to <c>Completed</c> or <c>Cancelled</c> — subsequent saves
    ///         do not overwrite those audit fields.</item>
    ///   <item>The resolution email is gated on three conditions: the status just
    ///         changed to <c>Completed</c>, resolution notes are non-empty, and the
    ///         submitter's user ID is still resolvable in Identity. Email failures
    ///         are logged as warnings but do not roll back the save.</item>
    ///   <item>The route-id / dto.Id equality check prevents CSRF-style ID-swap
    ///         attacks where a forged form targets a different record.</item>
    /// </list>
    /// </para>
    /// </summary>
    // POST: /BugReport/Edit/5 — SuperAdmin only
    [Authorize(Policy = AppConstants.Policies.SuperAdminOnly)]
    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task<IActionResult> Edit(int id, EditBugReportDto dto)
    {
        if (id != dto.Id)
            return BadRequest();

        if (!ModelState.IsValid)
            return View(dto);

        try
        {
            var bugReport = await _unitOfWork.BugReports.GetByIdAsync(id, ignoreQueryFilters: true);
            if (bugReport == null || bugReport.IsDeleted)
                return NotFound();

            var previousStatus = bugReport.Status;

            bugReport.Title = dto.Title;
            bugReport.Description = dto.Description;
            bugReport.Priority = dto.Priority;
            bugReport.Status = dto.Status;
            bugReport.ResolutionNotes = dto.ResolutionNotes;
            bugReport.UpdatedAt = DateTime.UtcNow;
            bugReport.UpdatedBy = User.Identity?.Name;

            var justCompleted = dto.Status == BugReportStatus.Completed
                && previousStatus != BugReportStatus.Completed;

            if (justCompleted || (dto.Status == BugReportStatus.Cancelled
                && previousStatus is not BugReportStatus.Completed and not BugReportStatus.Cancelled))
            {
                bugReport.ResolvedAt = DateTime.UtcNow;
                bugReport.ResolvedBy = User.Identity?.Name;
            }

            await _unitOfWork.BugReports.UpdateAsync(bugReport);
            await _unitOfWork.CompleteAsync();

            _logger.LogInformation("Bug report {Id} updated by {UserName}", id, User.Identity?.Name);

            // Email submitter when their report is completed and resolution notes are provided
            if (justCompleted && !string.IsNullOrWhiteSpace(dto.ResolutionNotes)
                && !string.IsNullOrWhiteSpace(bugReport.SubmittedByUserId))
            {
                var submitter = await _userManager.FindByIdAsync(bugReport.SubmittedByUserId);
                if (submitter != null && !string.IsNullOrWhiteSpace(submitter.Email))
                {
                    var resolvedBy = User.Identity?.Name ?? "Support";
                    var htmlBody = $"""
                        <h2>Your Bug Report Has Been Resolved</h2>
                        <p>Hi {System.Net.WebUtility.HtmlEncode(bugReport.SubmittedByUserName)},</p>
                        <p>We wanted to let you know that your bug report has been marked as completed.</p>
                        <table cellpadding="6" style="border-collapse:collapse;">
                            <tr><td><strong>Report:</strong></td><td>{System.Net.WebUtility.HtmlEncode(bugReport.Title)}</td></tr>
                            <tr><td><strong>Resolved By:</strong></td><td>{System.Net.WebUtility.HtmlEncode(resolvedBy)}</td></tr>
                            <tr><td><strong>Resolved At:</strong></td><td>{bugReport.ResolvedAt:MM/dd/yyyy h:mm tt} UTC</td></tr>
                        </table>
                        <h3>Resolution Notes</h3>
                        <p style="white-space:pre-wrap;">{System.Net.WebUtility.HtmlEncode(dto.ResolutionNotes)}</p>
                        <p>Thank you for helping us improve the platform!</p>
                        """;

                    var plainBody = $"Hi {bugReport.SubmittedByUserName},\n\nYour bug report \"{bugReport.Title}\" has been marked as completed.\n\nResolution Notes:\n{dto.ResolutionNotes}\n\nResolved by: {resolvedBy}\n\nThank you for helping us improve the platform!";

                    var emailResult = await _emailService.SendEmailAsync(
                        toEmail: submitter.Email,
                        toName: bugReport.SubmittedByUserName,
                        subject: $"[Resolved] {bugReport.Title}",
                        plainTextBody: plainBody,
                        htmlBody: htmlBody);

                    if (emailResult.Success)
                        _logger.LogInformation("Resolution email sent to {Email} for bug report {Id}", submitter.Email, id);
                    else
                        _logger.LogWarning("Failed to send resolution email for bug report {Id}: {Error}", id, emailResult.ErrorMessage);
                }
            }

            TempData["SuccessMessage"] = "Bug report updated successfully.";
            return RedirectToAction(nameof(Index));
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Error updating bug report {Id}", id);
            TempData["ErrorMessage"] = "An error occurred while saving the changes.";
            return View(dto);
        }
    }
}