@page "/settings"
@attribute [Authorize]
@using Microsoft.AspNetCore.Identity
@using Microsoft.EntityFrameworkCore
@inject UserManager<ApplicationUser> UserManager
@inject SignInManager<ApplicationUser> SignInManager
@inject AuthenticationStateProvider AuthStateProvider
@inject ApplicationDbContext DbContext
@inject NavigationManager Navigation
@inject AppState AppState
@rendermode InteractiveServer

<PageTitle>Settings</PageTitle>

<h3 class="mb-4">
    Settings
    <span class="badge bg-warning text-dark ms-2" style="font-size: 0.4em; vertical-align: middle;">beta</span>
</h3>

@* ── Change Password ── *@
<div class="card mb-4">
    <div class="card-header">
        <h5 class="mb-0">Change Password</h5>
    </div>
    <div class="card-body">
        @if (passwordSuccess)
        {
            <div class="alert alert-success">Password changed successfully.</div>
        }

        @if (!string.IsNullOrEmpty(passwordError))
        {
            <div class="alert alert-danger">@passwordError</div>
        }

        <EditForm Model="passwordForm" OnValidSubmit="ChangePassword" FormName="changePassword">
            <ToastValidator />
            <div class="row g-3">
                <div class="col-md-4">
                    <label class="form-label">Current Password</label>
                    <InputText @bind-Value="passwordForm.CurrentPassword" type="password" class="form-control" />
                </div>
                <div class="col-md-4">
                    <label class="form-label">New Password</label>
                    <InputText @bind-Value="passwordForm.NewPassword" type="password" class="form-control" />
                </div>
                <div class="col-md-4">
                    <label class="form-label">Confirm New Password</label>
                    <InputText @bind-Value="passwordForm.ConfirmNewPassword" type="password" class="form-control" />
                </div>
                <div class="col-12">
                    <button type="submit" class="btn btn-primary">Update Password</button>
                </div>
            </div>
        </EditForm>
    </div>
</div>

@* ── Reset Data ── *@
<div class="card mb-4 border-warning">
    <div class="card-header bg-warning">
        <h5 class="mb-0">Reset Data</h5>
    </div>
    <div class="card-body">
        <p class="fw-semibold">
            This will permanently delete all your accounts, transactions and categories, giving you a clean slate. Your user account and password will be kept.
        </p>

        @if (resetSuccess)
        {
            <div class="alert alert-success">All data has been reset successfully.</div>
        }

        @if (!string.IsNullOrEmpty(resetError))
        {
            <div class="alert alert-danger">@resetError</div>
        }

        @if (!confirmingReset)
        {
            <button class="btn btn-outline-warning" @onclick="() => confirmingReset = true">
                Reset All Data
            </button>
        }
        else
        {
            <div class="alert alert-warning">
                <strong>Are you sure?</strong> This cannot be undone. Type <code>I UNDERSTAND</code> and enter your password to confirm.
            </div>
            <div class="mb-3" style="max-width: 400px;">
                <input type="text" class="form-control mb-2" placeholder="Type I UNDERSTAND to confirm" @bind="resetConfirmation" />
                <input type="password" class="form-control mb-2" placeholder="Enter your password" @bind="resetPassword" />
                <div class="d-flex gap-2">
                    <button class="btn btn-warning" @onclick="ResetData">Confirm Reset</button>
                    <button class="btn btn-secondary" @onclick="CancelReset">Cancel</button>
                </div>
            </div>
        }
    </div>
</div>

@* ── Delete Account ── *@
<div class="card border-danger">
    <div class="card-header bg-danger text-white">
        <h5 class="mb-0">Delete Account</h5>
    </div>
    <div class="card-body">
        <p class="text-danger fw-semibold">
            This will permanently delete your account and all associated data (accounts, transactions, and categories). This action cannot be undone.
        </p>

        @if (!string.IsNullOrEmpty(deleteError))
        {
            <div class="alert alert-danger">@deleteError</div>
        }

        @if (!confirmingDelete)
        {
            <button class="btn btn-outline-danger" @onclick="() => confirmingDelete = true">
                Delete My Account
            </button>
        }
        else
        {
            <div class="alert alert-warning">
                <strong>Are you sure?</strong> Type your password to confirm.
            </div>
            <div class="input-group mb-3" style="max-width: 400px;">
                <input type="password" class="form-control" placeholder="Enter your password" @bind="deletePassword" />
                <button class="btn btn-danger" @onclick="DeleteAccount">Confirm Delete</button>
                <button class="btn btn-secondary" @onclick="CancelDelete">Cancel</button>
            </div>
        }
    </div>
</div>

@code {
    private static readonly string appVersion =
        typeof(Program).Assembly.GetName().Version?.ToString(3) ?? "0.0.0";

    private ChangePasswordForm passwordForm = new();
    private bool passwordSuccess;
    private string? passwordError;

    private bool confirmingDelete;
    private string deletePassword = string.Empty;
    private string? deleteError;

    private bool confirmingReset;
    private string resetConfirmation = string.Empty;
    private string resetPassword = string.Empty;
    private string? resetError;
    private bool resetSuccess;

    private async Task ChangePassword()
    {
        passwordSuccess = false;
        passwordError = null;

        var authState = await AuthStateProvider.GetAuthenticationStateAsync();
        var userIdClaim = authState.User.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier)?.Value;
        if (userIdClaim is null) return;

        var user = await UserManager.FindByIdAsync(userIdClaim);
        if (user is null) return;

        var result = await UserManager.ChangePasswordAsync(user, passwordForm.CurrentPassword, passwordForm.NewPassword);

        if (result.Succeeded)
        {
            passwordSuccess = true;
            passwordForm = new ChangePasswordForm();
        }
        else
        {
            passwordError = string.Join(" ", result.Errors.Select(e => e.Description));
        }
    }

    private async Task DeleteAccount()
    {
        deleteError = null;

        var authState = await AuthStateProvider.GetAuthenticationStateAsync();
        var userIdClaim = authState.User.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier)?.Value;
        if (userIdClaim is null) return;

        var user = await UserManager.FindByIdAsync(userIdClaim);
        if (user is null) return;

        var passwordValid = await UserManager.CheckPasswordAsync(user, deletePassword);
        if (!passwordValid)
        {
            deleteError = "Incorrect password.";
            return;
        }

        // Delete all user data explicitly in correct dependency order
        await DbContext.Transactions
            .Where(t => t.Account.UserId == userIdClaim)
            .ExecuteDeleteAsync();

        await DbContext.Accounts
            .Where(a => a.UserId == userIdClaim)
            .ExecuteDeleteAsync();

        await DbContext.Categories
            .Where(c => c.UserId == userIdClaim)
            .ExecuteDeleteAsync();

        // Delete identity user
        await UserManager.DeleteAsync(user);
        await SignInManager.SignOutAsync();

        Navigation.NavigateTo("/login", forceLoad: true);
    }

    private void CancelDelete()
    {
        confirmingDelete = false;
        deletePassword = string.Empty;
        deleteError = null;
    }

    private async Task ResetData()
    {
        resetError = null;
        resetSuccess = false;

        var authState = await AuthStateProvider.GetAuthenticationStateAsync();
        var userIdClaim = authState.User.FindFirst(System.Security.Claims.ClaimTypes.NameIdentifier)?.Value;
        if (userIdClaim is null) return;

        var user = await UserManager.FindByIdAsync(userIdClaim);
        if (user is null) return;

        if (!string.Equals(resetConfirmation?.Trim(), "I UNDERSTAND", StringComparison.Ordinal))
        {
            resetError = "Please type 'I UNDERSTAND' exactly to confirm.";
            return;
        }

        var passwordValid = await UserManager.CheckPasswordAsync(user, resetPassword);
        if (!passwordValid)
        {
            resetError = "Incorrect password.";
            return;
        }

        await DbContext.Transactions
            .Where(t => t.Account.UserId == userIdClaim)
            .ExecuteDeleteAsync();

        await DbContext.Accounts
            .Where(a => a.UserId == userIdClaim)
            .ExecuteDeleteAsync();

        await DbContext.Categories
            .Where(c => c.UserId == userIdClaim)
            .ExecuteDeleteAsync();

        confirmingReset = false;
        resetConfirmation = string.Empty;
        resetPassword = string.Empty;
        resetSuccess = true;

        AppState.NotifyAccountsChanged();
    }

    private void CancelReset()
    {
        confirmingReset = false;
        resetConfirmation = string.Empty;
        resetPassword = string.Empty;
        resetError = null;
    }

    private sealed class ChangePasswordForm
    {
        [System.ComponentModel.DataAnnotations.Required(ErrorMessage = "Current password is required")]
        public string CurrentPassword { get; set; } = string.Empty;

        [System.ComponentModel.DataAnnotations.Required(ErrorMessage = "New password is required")]
        [System.ComponentModel.DataAnnotations.MinLength(8, ErrorMessage = "Password must be at least 8 characters")]
        public string NewPassword { get; set; } = string.Empty;

        [System.ComponentModel.DataAnnotations.Required(ErrorMessage = "Please confirm your new password")]
        [System.ComponentModel.DataAnnotations.Compare(nameof(NewPassword), ErrorMessage = "Passwords do not match")]
        public string ConfirmNewPassword { get; set; } = string.Empty;
    }
}