using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Mime;
using System.Threading.Tasks;
using Jellyfin.Plugin.WatchedTogether.Models;
using Jellyfin.Plugin.WatchedTogether.Services;
using MediaBrowser.Common.Api;
using MediaBrowser.Controller.Library;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;

namespace Jellyfin.Plugin.WatchedTogether.Controllers;

/// <summary>
/// Administrative endpoints backing the configuration page.
/// </summary>
[ApiController]
[Authorize(Policy = Policies.RequiresElevation)]
[Route("Plugins/WatchedTogether")]
[Produces(MediaTypeNames.Application.Json)]
public class WatchedTogetherController : ControllerBase
{
    private readonly IProvisioningService _provisioningService;
    private readonly IUserManager _userManager;
    private readonly ILogger<WatchedTogetherController> _logger;

    /// <summary>
    /// Initializes a new instance of the <see cref="WatchedTogetherController"/> class.
    /// </summary>
    /// <param name="provisioningService">The provisioning service.</param>
    /// <param name="userManager">The user manager.</param>
    /// <param name="logger">The logger.</param>
    public WatchedTogetherController(
        IProvisioningService provisioningService,
        IUserManager userManager,
        ILogger<WatchedTogetherController> logger)
    {
        _provisioningService = provisioningService;
        _userManager = userManager;
        _logger = logger;
    }

    /// <summary>
    /// Gets every configured group, resolved against current user records.
    /// </summary>
    /// <returns>The configured groups.</returns>
    [HttpGet("Groups")]
    [ProducesResponseType(StatusCodes.Status200OK)]
    public ActionResult<IEnumerable<GroupDto>> GetGroups()
    {
        var config = Plugin.Instance?.Configuration;
        if (config is null)
        {
            return Ok(Array.Empty<GroupDto>());
        }

        var groups = config.Groups.Select(g => new GroupDto
        {
            SharedUserId = g.SharedUserId,
            SharedUsername = _userManager.GetUserById(g.SharedUserId)?.Username ?? "(deleted)",
            SyncUnwatched = g.SyncUnwatched,
            SyncPlayCount = g.SyncPlayCount,
            IsDisabled = g.IsDisabled,
            Members = g.MemberUserIds.Select(id => new MemberDto
            {
                UserId = id,
                Username = _userManager.GetUserById(id)?.Username ?? "(deleted)"
            }).ToList()
        }).ToList();

        return Ok(groups);
    }

    /// <summary>
    /// Gets the users that may be selected as members - everyone who is not already a shared account.
    /// </summary>
    /// <returns>The eligible users.</returns>
    [HttpGet("EligibleUsers")]
    [ProducesResponseType(StatusCodes.Status200OK)]
    public ActionResult<IEnumerable<MemberDto>> GetEligibleUsers()
    {
        var sharedIds = Plugin.Instance?.Configuration.Groups
            .Select(g => g.SharedUserId)
            .ToHashSet() ?? [];

        var users = _userManager.Users
            .Where(u => !sharedIds.Contains(u.Id))
            .Select(u => new MemberDto { UserId = u.Id, Username = u.Username })
            .OrderBy(u => u.Username, StringComparer.OrdinalIgnoreCase)
            .ToList();

        return Ok(users);
    }

    /// <summary>
    /// Creates a shared account and its group.
    /// </summary>
    /// <param name="request">The group to create.</param>
    /// <returns>The created group.</returns>
    [HttpPost("Groups")]
    [ProducesResponseType(StatusCodes.Status200OK)]
    [ProducesResponseType(StatusCodes.Status400BadRequest)]
    public async Task<ActionResult<GroupDto>> CreateGroup([FromBody] CreateGroupRequest request)
    {
        ArgumentNullException.ThrowIfNull(request);

        try
        {
            var group = await _provisioningService.CreateGroupAsync(
                request.MemberUserIds,
                request.Name).ConfigureAwait(false);

            return Ok(new GroupDto
            {
                SharedUserId = group.SharedUserId,
                SharedUsername = _userManager.GetUserById(group.SharedUserId)?.Username ?? string.Empty,
                SyncUnwatched = group.SyncUnwatched,
                SyncPlayCount = group.SyncPlayCount,
                IsDisabled = group.IsDisabled,
                Members = group.MemberUserIds.Select(id => new MemberDto
                {
                    UserId = id,
                    Username = _userManager.GetUserById(id)?.Username ?? "(deleted)"
                }).ToList()
            });
        }
        catch (ArgumentException ex)
        {
            _logger.LogWarning(ex, "Rejected group creation request");
            return BadRequest(ex.Message);
        }
    }

    /// <summary>
    /// Updates an existing group's membership and options.
    /// </summary>
    /// <param name="sharedUserId">The shared account identifying the group.</param>
    /// <param name="request">The new membership and options.</param>
    /// <returns>No content on success.</returns>
    [HttpPost("Groups/{sharedUserId}")]
    [ProducesResponseType(StatusCodes.Status204NoContent)]
    [ProducesResponseType(StatusCodes.Status400BadRequest)]
    public async Task<ActionResult> UpdateGroup(
        [FromRoute] Guid sharedUserId,
        [FromBody] UpdateGroupRequest request)
    {
        ArgumentNullException.ThrowIfNull(request);

        try
        {
            await _provisioningService.UpdateGroupAsync(
                sharedUserId,
                request.MemberUserIds,
                request.SyncUnwatched,
                request.SyncPlayCount,
                request.IsDisabled).ConfigureAwait(false);

            return NoContent();
        }
        catch (ArgumentException ex)
        {
            _logger.LogWarning(ex, "Rejected group update request");
            return BadRequest(ex.Message);
        }
    }

    /// <summary>
    /// Deletes a group, optionally deleting its shared account too.
    /// </summary>
    /// <param name="sharedUserId">The shared account identifying the group.</param>
    /// <param name="deleteSharedUser">Whether to delete the shared account as well.</param>
    /// <returns>No content on success.</returns>
    [HttpDelete("Groups/{sharedUserId}")]
    [ProducesResponseType(StatusCodes.Status204NoContent)]
    [ProducesResponseType(StatusCodes.Status400BadRequest)]
    public async Task<ActionResult> DeleteGroup(
        [FromRoute] Guid sharedUserId,
        [FromQuery] bool deleteSharedUser = false)
    {
        try
        {
            await _provisioningService.DeleteGroupAsync(sharedUserId, deleteSharedUser).ConfigureAwait(false);
            return NoContent();
        }
        catch (ArgumentException ex)
        {
            _logger.LogWarning(ex, "Rejected group deletion request");
            return BadRequest(ex.Message);
        }
    }
}