using CalendarReminder.Api.Data;
using CalendarReminder.Api.Services;
using CalendarReminder.Domain.Entities;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using System.Security.Claims;

namespace CalendarReminder.Api.Controllers;

[Authorize]
[ApiController]
[Route("api/[controller]")]
public class RemindersController : ControllerBase
{
    private readonly AppDbContext _db;
    private readonly EmailService _email;

    public RemindersController(AppDbContext db, EmailService email)
    {
        _db = db;
        _email = email;
    }

    private int UserId => int.Parse(User.FindFirstValue(ClaimTypes.NameIdentifier)!);

    // GET api/reminders  — moje + zdieľané so mnou
    [HttpGet]
    public async Task<IActionResult> GetAll()
    {
        var myId = UserId;

        var reminders = await _db.Reminders
            .Include(r => r.User)
            .Include(r => r.Shares).ThenInclude(s => s.SharedWithUser)
            .Where(r => r.UserId == myId || r.Shares.Any(s => s.SharedWithUserId == myId))
            .OrderBy(r => r.ReminderDate)
            .Select(r => new
            {
                r.Id, r.Title, r.Description, r.ReminderDate,
                r.IsCompleted, r.NotificationSent, r.UserId, r.CreatedAt,
                Owner = r.User!.Username,
                IsOwner = r.UserId == myId,
                SharedWith = r.Shares.Select(s => new { s.SharedWithUser!.Id, s.SharedWithUser.Username })
            })
            .ToListAsync();

        return Ok(reminders);
    }

    // GET api/reminders/5
    [HttpGet("{id}")]
    public async Task<IActionResult> GetById(int id)
    {
        var myId = UserId;
        var r = await _db.Reminders
            .Include(r => r.Shares)
            .FirstOrDefaultAsync(r => r.Id == id &&
                (r.UserId == myId || r.Shares.Any(s => s.SharedWithUserId == myId)));
        return r is null ? NotFound() : Ok(r);
    }

    // POST api/reminders
    [HttpPost]
    public async Task<IActionResult> Create([FromBody] CreateReminderRequest req)
    {
        var reminder = new Reminder
        {
            Title = req.Title,
            Description = req.Description,
            ReminderDate = req.ReminderDate,
            IsCompleted = false,
            NotificationSent = false,
            UserId = UserId,
            CreatedAt = DateTime.UtcNow
        };
        _db.Reminders.Add(reminder);
        await _db.SaveChangesAsync();

        // Zdieľaj s vybranými používateľmi
        foreach (var uid in req.ShareWithUserIds ?? [])
        {
            _db.ReminderShares.Add(new ReminderShare { ReminderId = reminder.Id, SharedWithUserId = uid });
        }
        if (req.ShareWithUserIds?.Count > 0)
            await _db.SaveChangesAsync();

        return CreatedAtAction(nameof(GetById), new { id = reminder.Id }, reminder);
    }

    // PUT api/reminders/5
    [HttpPut("{id}")]
    public async Task<IActionResult> Update(int id, [FromBody] UpdateReminderRequest req)
    {
        var reminder = await _db.Reminders
            .Include(r => r.Shares)
            .FirstOrDefaultAsync(r => r.Id == id && r.UserId == UserId);
        if (reminder is null) return NotFound();

        bool dateChanged = reminder.ReminderDate != req.ReminderDate;
        reminder.Title = req.Title;
        reminder.Description = req.Description;
        reminder.ReminderDate = req.ReminderDate;
        reminder.IsCompleted = req.IsCompleted;
        if (dateChanged) reminder.NotificationSent = false;

        // Aktualizuj zdieľanie
        _db.ReminderShares.RemoveRange(reminder.Shares);
        foreach (var uid in req.ShareWithUserIds ?? [])
            _db.ReminderShares.Add(new ReminderShare { ReminderId = id, SharedWithUserId = uid });

        await _db.SaveChangesAsync();
        return Ok(reminder);
    }

    // DELETE api/reminders/5
    [HttpDelete("{id}")]
    public async Task<IActionResult> Delete(int id)
    {
        var reminder = await _db.Reminders
            .FirstOrDefaultAsync(r => r.Id == id && r.UserId == UserId);
        if (reminder is null) return NotFound();
        _db.Reminders.Remove(reminder);
        await _db.SaveChangesAsync();
        return NoContent();
    }

    // POST api/reminders/5/send-email
    [HttpPost("{id}/send-email")]
    public async Task<IActionResult> SendEmail(int id)
    {
        var myId = UserId;
        var reminder = await _db.Reminders
            .Include(r => r.User)
            .Include(r => r.Shares).ThenInclude(s => s.SharedWithUser)
            .FirstOrDefaultAsync(r => r.Id == id && r.UserId == myId);

        if (reminder is null) return NotFound();
        if (!reminder.Shares.Any()) return BadRequest("Pripomienka nie je zdieľaná so žiadnym používateľom.");

        var date = reminder.ReminderDate.ToLocalTime();
        var dateStr = date.ToString("dd.MM.yyyy");
        var timeStr = date.ToString("HH:mm");

        var body = $"""
            <div style="font-family:Segoe UI,sans-serif;max-width:520px;margin:auto;background:#161b22;color:#e1e4e8;border-radius:10px;overflow:hidden">
              <div style="background:#1f6feb;padding:1.2rem 1.5rem">
                <h2 style="margin:0;color:#fff;font-size:1.1rem">📅 Calendar Reminder</h2>
              </div>
              <div style="padding:1.5rem">
                <h3 style="margin:0 0 1rem;color:#58a6ff;font-size:1.2rem">{reminder.Title}</h3>
                <table style="width:100%;border-collapse:collapse">
                  <tr>
                    <td style="padding:0.4rem 0;color:#8b949e;width:80px">Dátum</td>
                    <td style="padding:0.4rem 0;font-weight:600">{dateStr}</td>
                  </tr>
                  <tr>
                    <td style="padding:0.4rem 0;color:#8b949e">Čas</td>
                    <td style="padding:0.4rem 0;font-weight:600">{timeStr}</td>
                  </tr>
                  {(reminder.Description != null ? $"""
                  <tr>
                    <td style="padding:0.4rem 0;color:#8b949e;vertical-align:top">Popis</td>
                    <td style="padding:0.4rem 0">{reminder.Description}</td>
                  </tr>
                  """ : "")}
                  <tr>
                    <td style="padding:0.4rem 0;color:#8b949e">Od</td>
                    <td style="padding:0.4rem 0">{reminder.User!.Username}</td>
                  </tr>
                </table>
              </div>
              <div style="padding:0.75rem 1.5rem;border-top:1px solid #30363d;font-size:0.78rem;color:#6e7681">
                Calendar Reminder — automatická správa
              </div>
            </div>
            """;

        var tasks = reminder.Shares
            .Where(s => s.SharedWithUser != null)
            .Select(s => _email.SendAsync(
                s.SharedWithUser!.Email,
                s.SharedWithUser.Username,
                $"📅 Pripomienka: {reminder.Title} — {dateStr} {timeStr}",
                body));

        await Task.WhenAll(tasks);
        return Ok(new { sent = reminder.Shares.Count });
    }
}

public record CreateReminderRequest(
    string Title,
    string? Description,
    DateTime ReminderDate,
    List<int>? ShareWithUserIds);

public record UpdateReminderRequest(
    string Title,
    string? Description,
    DateTime ReminderDate,
    bool IsCompleted,
    List<int>? ShareWithUserIds);