using System.Net.Http.Json;
using System.Text.Json;

namespace SoroushAsadi.Services;

public class EmailService(HttpClient http, IConfiguration config, ILogger<EmailService> logger)
{
    private string? ApiKey => config["RESEND_API_KEY"] ?? Environment.GetEnvironmentVariable("RESEND_API_KEY");
    private string? Inbox  => config["CONTACT_INBOX"]  ?? Environment.GetEnvironmentVariable("CONTACT_INBOX");
    private string? From   => config["CONTACT_FROM"]   ?? Environment.GetEnvironmentVariable("CONTACT_FROM");

    public record ContactForm(
        string Name, string Company, string Service,
        string Budget, string Message, string Locale);

    /// <returns>null on success, error string on failure.</returns>
    public async Task<string?> SendContactAsync(ContactForm form)
    {
        if (ApiKey is null || Inbox is null || From is null)
        {
            logger.LogInformation("[contact] received (no Resend key — logging only): {Name}", form.Name);
            return null; // dev no-op
        }

        var html = $"""
            <div style="font-family:ui-sans-serif,system-ui,sans-serif;line-height:1.55">
              <h2 style="margin:0 0 12px">New consultation request</h2>
              <table style="border-collapse:collapse">
                <tr><td style="padding:4px 12px 4px 0;color:#475569">Name</td><td>{Esc(form.Name)}</td></tr>
                <tr><td style="padding:4px 12px 4px 0;color:#475569">Company</td><td>{Esc(form.Company)}</td></tr>
                <tr><td style="padding:4px 12px 4px 0;color:#475569">Service</td><td>{Esc(form.Service)}</td></tr>
                <tr><td style="padding:4px 12px 4px 0;color:#475569">Budget</td><td>{Esc(form.Budget)}</td></tr>
                <tr><td style="padding:4px 12px 4px 0;color:#475569">Locale</td><td>{Esc(form.Locale)}</td></tr>
              </table>
              <h3 style="margin:20px 0 6px">Message</h3>
              <p style="white-space:pre-wrap;background:#f8fafc;padding:12px;border-radius:8px">{Esc(form.Message)}</p>
            </div>
            """;

        using var req = new HttpRequestMessage(HttpMethod.Post, "https://api.resend.com/emails");
        req.Headers.Add("Authorization", $"Bearer {ApiKey}");
        req.Content = JsonContent.Create(new
        {
            from = From,
            to = new[] { Inbox },
            subject = $"New consultation request — {form.Name}",
            html
        });

        try
        {
            var res = await http.SendAsync(req);
            if (!res.IsSuccessStatusCode)
            {
                var body = await res.Content.ReadAsStringAsync();
                logger.LogError("[contact] Resend error {Status}: {Body}", res.StatusCode, body);
                return "Email service rejected the request.";
            }
            return null;
        }
        catch (Exception ex)
        {
            logger.LogError(ex, "[contact] Send failed");
            return "Email service unreachable.";
        }
    }

    private static string Esc(string? s) => System.Web.HttpUtility.HtmlEncode(s ?? "");
}