myAi/Jobs/cv-search-job/Services/CvSearchEmailSender.cs

using CvMatcher.Models.Responses;
using CvSearch.Data.Entities;
using Email.Data.Services;
using EmailApi.Models.Clients;
using EmailApi.Models.Requests;
using Microsoft.Extensions.Logging;

namespace CvSearchJob.Services;

/// <summary>
/// Sends job search results emails to the session user and the operator copy address,
/// with an optional CV PDF attachment.
/// </summary>
public sealed class CvSearchEmailSender
{
    private readonly IEmailApiClient _emailApi;
    private readonly IEmailTemplateService _emailTemplates;
    private readonly ILogger<CvSearchEmailSender> _logger;

    public CvSearchEmailSender(
        IEmailApiClient emailApi,
        IEmailTemplateService emailTemplates,
        ILogger<CvSearchEmailSender> logger)
    {
        _emailApi = emailApi;
        _emailTemplates = emailTemplates;
        _logger = logger;
    }

    /// <summary>
    /// Builds and sends the job search results email.
    /// Resolves the recipient list from <paramref name="toEmail"/> and the operator copy address
    /// stored in the email template. Does nothing when no recipients can be resolved.
    /// </summary>
    /// <param name="toEmail">Primary recipient (the user who triggered the search).</param>
    /// <param name="attachmentFileName">Relative filename of the CV PDF to attach, or <c>null</c>.</param>
    /// <param name="results">Ranked list of job search results to include in the email body.</param>
    /// <param name="keywords">CV keywords used to drive the job search.</param>
    /// <param name="providerNames">Names of the providers that were scanned.</param>
    /// <param name="language">Two-letter language code for template rendering.</param>
    /// <param name="ct">Cancellation token.</param>
    public async Task SendResultsAsync(
        string toEmail,
        string? attachmentFileName,
        IReadOnlyList<JobSearchResultEntity> results,
        IReadOnlyList<string> keywords,
        IReadOnlyList<string> providerNames,
        string language,
        CancellationToken ct)
    {
        var operatorCopy = _emailTemplates.GetOperatorCopy("email.search-results.subject", language);

        var recipients = new List<string>();
        if (!string.IsNullOrWhiteSpace(toEmail)) recipients.Add(toEmail);
        if (!string.IsNullOrWhiteSpace(operatorCopy) &&
            !recipients.Any(r => string.Equals(r, operatorCopy, StringComparison.OrdinalIgnoreCase)))
            recipients.Add(operatorCopy);

        if (recipients.Count == 0) return;

        var htmlBody = BuildBody(results, keywords, providerNames, language);
        var subject = _emailTemplates.Render("email.search-results.subject", language,
            ("count", results.Count.ToString()));

        try
        {
            await _emailApi.SendAsync(new SendEmailRequest
            {
                To = recipients,
                Subject = subject,
                HtmlBody = htmlBody,
                AttachmentPath = attachmentFileName
            }, ct);

            _logger.LogInformation("Job search results email sent to {Recipients}",
                string.Join(", ", recipients));
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Failed to send job search results email to {Recipients}",
                string.Join(", ", recipients));
        }
    }

    /// <summary>
    /// Renders the HTML email body from the results list.
    /// Returns the empty-results template when no results are present.
    /// Prepends a scan summary block showing the keywords and providers used.
    /// </summary>
    private string BuildBody(IReadOnlyList<JobSearchResultEntity> results, IReadOnlyList<string> keywords, IReadOnlyList<string> providerNames, string language)
    {
        var scanSummary = BuildScanSummary(keywords, providerNames);

        if (results.Count == 0)
            return scanSummary + _emailTemplates.Get("email.search-results.empty", language);

        var items = new System.Text.StringBuilder();
        for (int i = 0; i < results.Count; i++)
        {
            var r = results[i];
            var matchResp = TryParseResult(r.ResultJson);
            var summary = matchResp?.Summary;

            items.Append($"""
                <div style="border:1px solid #dee2e6;border-radius:6px;padding:16px;margin-bottom:12px">
                  <strong style="color:#212529">{i + 1}. {r.JobTitle}</strong>
                  <span style="background:#28a745;color:#fff;padding:2px 8px;border-radius:12px;font-size:12px;margin-left:8px">{r.Score}% match</span>
                  <span style="color:#6c757d;font-size:12px;margin-left:4px">[{r.ProviderName}]</span><br>
                  <a href="{r.JobUrl}" style="color:#2c5282;font-size:13px">{r.JobUrl}</a>
                  {(string.IsNullOrWhiteSpace(summary) ? "" : $"<p style=\"margin:8px 0 0;color:#495057;font-size:14px;line-height:1.5\">{summary}</p>")}
                </div>
                """);
        }

        return _emailTemplates.Render("email.search-results.body", language,
            ("count", results.Count.ToString()),
            ("items", scanSummary + items.ToString()));
    }

    /// <summary>
    /// Builds the scan summary block showing the CV keywords and providers used for the search.
    /// </summary>
    private static string BuildScanSummary(IReadOnlyList<string> keywords, IReadOnlyList<string> providerNames)
    {
        var keywordsHtml = keywords.Count > 0
            ? string.Join(" ", keywords.Select(k =>
                $"<span style=\"display:inline-block;background:#e9ecef;border-radius:4px;padding:2px 8px;margin:2px 2px 2px 0;font-size:12px\">{k}</span>"))
            : "<span style=\"color:#6c757d;font-size:12px;font-style:italic\">none detected</span>";

        var providersText = providerNames.Count > 0
            ? string.Join(", ", providerNames)
            : "none";

        return $"""
            <div style="background:#f8f9fa;border:1px solid #dee2e6;border-radius:6px;padding:14px 16px;margin-bottom:18px;font-size:13px;color:#495057">
              <div style="margin-bottom:8px"><strong>Keywords used:</strong>&nbsp;{keywordsHtml}</div>
              <div><strong>Providers scanned:</strong>&nbsp;{providersText}</div>
            </div>
            """;
    }

    /// <summary>
    /// Attempts to deserialise the stored result JSON into a <see cref="JobMatchResponse"/>.
    /// Returns <c>null</c> on parse failure so the email still renders without a summary.
    /// </summary>
    private static JobMatchResponse? TryParseResult(string json)
    {
        try
        {
            return System.Text.Json.JsonSerializer.Deserialize<JobMatchResponse>(json,
                new System.Text.Json.JsonSerializerOptions(System.Text.Json.JsonSerializerDefaults.Web));
        }
        catch { return null; }
    }
}