Quartz.NET Scheduled Jobs

# Install packages
dotnet add package Quartz
dotnet add package Quartz.AspNetCore

# Optional: persistence (requires Quartz.Serialization.Json too)
# dotnet add package Quartz.Jobs
# dotnet add package Quartz.Plugins

using Quartz;

[DisallowConcurrentExecution] // prevent overlapping executions
public class ReportGeneratorJob : IJob
{
    private readonly IReportService _reports;
    private readonly ILogger<ReportGeneratorJob> _logger;

    public ReportGeneratorJob(IReportService r, ILogger<ReportGeneratorJob> l)
    { _reports = r; _logger = l; }

    public async Task Execute(IJobExecutionContext context)
    {
        _logger.LogInformation("Generating report at {Time}", DateTime.UtcNow);
        await _reports.GenerateDailyReportAsync(context.CancellationToken);
        _logger.LogInformation("Report generated");
    }
}

builder.Services.AddQuartz(q =>
{
    q.UseMicrosoftDependencyInjectionJobFactory();

    var jobKey = new JobKey("ReportGenerator");
    q.AddJob<ReportGeneratorJob>(opts => opts.WithIdentity(jobKey));

    q.AddTrigger(opts => opts
        .ForJob(jobKey)
        .WithIdentity("ReportTrigger")
        .WithCronSchedule("0 0 8 * * ?") // 8:00 AM daily
    );
});

builder.Services.AddQuartzHostedService(q =>
    q.WaitForJobsToComplete = true);

// Quartz cron format: sec min hour dom month dow [year]

"0 0 8 * * ?"     // Every day at 8:00 AM
"0 0/30 9-17 * * ?" // Every 30 min, 9 AM - 5 PM weekdays
"0 0 0 1 * ?"     // First day of every month at midnight
"0 0 6 ? * MON-FRI" // Every weekday at 6 AM
"0 0/5 * * * ?"   // Every 5 minutes

// Tip: use cronmaker.com or crontab.guru to build expressions

q.AddTrigger(opts => opts
    .ForJob(jobKey)
    .WithIdentity("CleanupTrigger")
    .StartNow()
    .WithSimpleSchedule(s => s
        .WithIntervalInHours(1)
        .RepeatForever())
);

// Or a one-shot trigger:
q.AddTrigger(opts => opts
    .ForJob(jobKey)
    .WithIdentity("OneShot")
    .StartAt(DateTimeOffset.UtcNow.AddMinutes(5)));

q.AddJob<EmailJob>(opts => opts
    .WithIdentity("EmailJob")
    .UsingJobData("to", "admin@example.com")
    .UsingJobData("subject", "Daily Digest"));

// Inside the job:
public async Task Execute(IJobExecutionContext context)
{
    var to      = context.JobDetail.JobDataMap.GetString("to");
    var subject = context.JobDetail.JobDataMap.GetString("subject");
    await _mailer.SendAsync(to!, subject!, "body");
}

[DisallowConcurrentExecution]
public class InventorySyncJob : IJob
{
    // If a sync takes > 1 minute and triggers every minute,
    // the next trigger is delayed until this one completes

    public async Task Execute(IJobExecutionContext context)
    {
        await SyncInventoryAsync(context.CancellationToken);
    }
}

// Without [DisallowConcurrentExecution], multiple instances
// could run in parallel, causing data conflicts.

public async Task Execute(IJobExecutionContext context)
{
    try
    {
        await ProcessAsync(context.CancellationToken);
    }
    catch (TransientException ex)
    {
        // Ask Quartz to retry immediately
        var jobException = new JobExecutionException(ex)
        {
            RefireImmediately = true
        };
        throw jobException;
    }
    catch (Exception ex)
    {
        _logger.LogError(ex, "Job failed — not retrying");
        // Don't rethrow — job is done
    }
}

builder.Services.AddQuartz(q =>
{
    q.UseMicrosoftDependencyInjectionJobFactory();

    // Daily report at 8 AM
    var reportKey = new JobKey("DailyReport");
    q.AddJob<ReportGeneratorJob>(o => o.WithIdentity(reportKey));
    q.AddTrigger(o => o.ForJob(reportKey)
        .WithCronSchedule("0 0 8 * * ?"));

    // Inventory sync every 15 minutes
    var syncKey = new JobKey("InventorySync");
    q.AddJob<InventorySyncJob>(o => o.WithIdentity(syncKey));
    q.AddTrigger(o => o.ForJob(syncKey)
        .WithSimpleSchedule(s => s
            .WithIntervalInMinutes(15)
            .RepeatForever()));

    // Cache cleanup every night at 2 AM
    var cacheKey = new JobKey("CacheCleanup");
    q.AddJob<CacheCleanupJob>(o => o.WithIdentity(cacheKey));
    q.AddTrigger(o => o.ForJob(cacheKey)
        .WithCronSchedule("0 0 2 * * ?"));
});