@{
    ViewData["Title"] = "Home";
}

<div class="card">
    <h1>📅 Calendar Sync</h1>
    <p>
        This application synchronizes your Microsoft 365 Calendar changes into an
        Excel Online file (<strong>CalendarSync.xlsx</strong>) in your OneDrive root folder every hour.
    </p>

    @if (User.Identity?.IsAuthenticated == true)
    {
        <p>You're signed in. Click <strong>Enroll</strong> to opt into calendar synchronization.</p>
        <a asp-action="Enroll" class="btn btn-primary">Enroll for Sync</a>
    }
    else
    {
        <p>Sign in with your Microsoft 365 account to get started.</p>
        <a asp-area="MicrosoftIdentity" asp-controller="Account" asp-action="SignIn" class="btn btn-primary">
            Sign In with Microsoft
        </a>
    }
</div>

<div class="card">
    <h2>How it works</h2>
    <ol>
        <li><strong>Sign In</strong> — Authenticate with your Microsoft 365 account.</li>
        <li><strong>Enroll</strong> — Register for calendar sync (stores your user ID securely).</li>
        <li><strong>Auto-Sync</strong> — Every 60 minutes, the background worker pulls calendar changes
            using Microsoft Graph delta queries and appends them to <code>CalendarSync.xlsx</code>.</li>
        <li><strong>Resume</strong> — Delta links are saved per user, so syncs resume exactly where they
            left off — even after a server restart.</li>
    </ol>
</div>