using Data.SeaHavenIndustries.Enums;
using SeaHaven.DataServices.Dto;
using SeaHaven.DataServices.Interfaces;
using SeaHaven.Services.Constants;
using SeaHaven.Services.DTOs;
using SeaHaven.Services.Interfaces;
using System.Security.Claims;

namespace SeaHaven.Services.Implementation;

public sealed class TeamPermissionService : ITeamPermissionService
{
    private readonly ITeamPermissionOverrideDataService _dataService;
    private readonly ITeamPermissionPolicy _policy;

    public TeamPermissionService(
        ITeamPermissionOverrideDataService dataService,
        ITeamPermissionPolicy policy)
    {
        _dataService = dataService;
        _policy = policy;
    }

    public async Task<TeamPermissionResult<TeamPermissionProfileDTO>> GetProfileAsync(
        string userId,
        ClaimsPrincipal caller,
        CancellationToken cancellationToken)
    {
        if (!IsAdmin(caller))
            return TeamPermissionResult<TeamPermissionProfileDTO>.Failure(TeamPermissionResultStatus.Forbidden);

        var user = await _dataService.GetUserAsync(userId, cancellationToken);
        return user is null
            ? TeamPermissionResult<TeamPermissionProfileDTO>.Failure(TeamPermissionResultStatus.NotFound)
            : TeamPermissionResult<TeamPermissionProfileDTO>.Success(BuildProfile(user));
    }

    public async Task<TeamPermissionResult<EffectivePermissionsDTO>> GetEffectivePermissionsAsync(
        ClaimsPrincipal caller,
        CancellationToken cancellationToken)
    {
        var userId = caller?.Identity?.IsAuthenticated == true
            ? caller.FindFirstValue(ClaimTypes.NameIdentifier)
            : null;
        if (string.IsNullOrWhiteSpace(userId))
            return TeamPermissionResult<EffectivePermissionsDTO>.Failure(TeamPermissionResultStatus.Unauthorized);

        var user = await _dataService.GetUserAsync(userId, cancellationToken);
        if (user is null)
            return TeamPermissionResult<EffectivePermissionsDTO>.Failure(TeamPermissionResultStatus.Unauthorized);

        return TeamPermissionResult<EffectivePermissionsDTO>.Success(new EffectivePermissionsDTO
        {
            Permissions = TeamPermissionKeys.All
                .Where(key => _policy.IsAllowed(user.RoleName, key, user.Overrides))
                .ToList()
        });
    }

    public async Task<TeamPermissionResult<TeamPermissionProfileDTO>> SetOverrideAsync(
        string userId,
        string permissionKey,
        UserPermissionState state,
        ClaimsPrincipal caller,
        CancellationToken cancellationToken)
    {
        if (!IsAdmin(caller))
            return TeamPermissionResult<TeamPermissionProfileDTO>.Failure(TeamPermissionResultStatus.Forbidden);

        var canonicalKey = TeamPermissionKeys.All.FirstOrDefault(
            key => string.Equals(key, permissionKey, StringComparison.OrdinalIgnoreCase));
        if (canonicalKey is null)
            return TeamPermissionResult<TeamPermissionProfileDTO>.Failure(
                TeamPermissionResultStatus.InvalidPermissionKey);

        var user = await _dataService.GetUserAsync(userId, cancellationToken);
        if (user is null)
            return TeamPermissionResult<TeamPermissionProfileDTO>.Failure(TeamPermissionResultStatus.NotFound);

        await _dataService.SetOverrideAsync(userId, canonicalKey, state, cancellationToken);

        var updatedOverrides = user.Overrides.ToDictionary(
            pair => pair.Key,
            pair => pair.Value,
            StringComparer.OrdinalIgnoreCase);
        updatedOverrides[canonicalKey] = state;

        return TeamPermissionResult<TeamPermissionProfileDTO>.Success(
            BuildProfile(new TeamPermissionUserData
            {
                UserId = user.UserId,
                RoleName = user.RoleName,
                Overrides = updatedOverrides
            }));
    }

    private TeamPermissionProfileDTO BuildProfile(TeamPermissionUserData user)
    {
        return new TeamPermissionProfileDTO
        {
            UserId = user.UserId,
            RoleName = user.RoleName,
            Permissions = TeamPermissionKeys.All
                .Select(key => new TeamPermissionValueDTO
                {
                    PermissionKey = key,
                    OverrideState = user.Overrides.TryGetValue(key, out var state)
                        ? state
                        : UserPermissionState.Unset,
                    IsGranted = _policy.IsAllowed(user.RoleName, key, user.Overrides)
                })
                .ToList()
        };
    }

    private static bool IsAdmin(ClaimsPrincipal? caller) =>
        caller?.IsInRole("Admin") == true;
}