// Create an instance of builder that exposes various extensions for adding resilience strategies
ResiliencePipeline pipeline = new ResiliencePipelineBuilder()
    .AddRetry(new RetryStrategyOptions()) // Add retry using the default options
    .AddTimeout(TimeSpan.FromSeconds(10)) // Add 10 seconds timeout
    .Build(); // Builds the resilience pipeline

// Execute the pipeline asynchronously
await pipeline.ExecuteAsync(static async token => { /* Your custom logic goes here */ }, cancellationToken);

var services = new ServiceCollection();

// Define a resilience pipeline with the name "my-pipeline"
services.AddResiliencePipeline("my-pipeline", builder =>
{
    builder
        .AddRetry(new RetryStrategyOptions())
        .AddTimeout(TimeSpan.FromSeconds(10));
});

// Build the service provider
var serviceProvider = services.BuildServiceProvider();

// Retrieve a ResiliencePipelineProvider that dynamically creates and caches the resilience pipelines
var pipelineProvider = serviceProvider.GetRequiredService<ResiliencePipelineProvider<string>>();

// Retrieve your resilience pipeline using the name it was registered with
ResiliencePipeline pipeline = pipelineProvider.GetPipeline("my-pipeline");

// Alternatively, you can use keyed services to retrieve the resilience pipeline
pipeline = serviceProvider.GetRequiredKeyedService<ResiliencePipeline>("my-pipeline");

// Execute the pipeline
await pipeline.ExecuteAsync(static async token =>
{
    // Your custom logic goes here
});

// Retry using the default options.
// See https://www.pollydocs.org/strategies/retry#defaults for defaults.
var optionsDefaults = new RetryStrategyOptions();

// For instant retries with no delay
var optionsNoDelay = new RetryStrategyOptions
{
    Delay = TimeSpan.Zero
};

// For advanced control over the retry behavior, including the number of attempts,
// delay between retries, and the types of exceptions to handle.
var optionsComplex = new RetryStrategyOptions
{
    ShouldHandle = new PredicateBuilder().Handle<SomeExceptionType>(),
    BackoffType = DelayBackoffType.Exponential,
    UseJitter = true,  // Adds a random factor to the delay
    MaxRetryAttempts = 4,
    Delay = TimeSpan.FromSeconds(3),
};

// To use a custom function to generate the delay for retries
var optionsDelayGenerator = new RetryStrategyOptions
{
    MaxRetryAttempts = 2,
    DelayGenerator = static args =>
    {
        var delay = args.AttemptNumber switch
        {
            0 => TimeSpan.Zero,
            1 => TimeSpan.FromSeconds(1),
            _ => TimeSpan.FromSeconds(5)
        };

        // This example uses a synchronous delay generator,
        // but the API also supports asynchronous implementations.
        return new ValueTask<TimeSpan?>(delay);
    }
};

// To extract the delay from the result object
var optionsExtractDelay = new RetryStrategyOptions<HttpResponseMessage>
{
    DelayGenerator = static args =>
    {
        if (args.Outcome.Result is HttpResponseMessage responseMessage &&
            TryGetDelay(responseMessage, out TimeSpan delay))
        {
            return new ValueTask<TimeSpan?>(delay);
        }

        // Returning null means the retry strategy will use its internal delay for this attempt.
        return new ValueTask<TimeSpan?>((TimeSpan?)null);
    }
};

// To get notifications when a retry is performed
var optionsOnRetry = new RetryStrategyOptions
{
    MaxRetryAttempts = 2,
    OnRetry = static args =>
    {
        Console.WriteLine("OnRetry, Attempt: {0}", args.AttemptNumber);

        // Event handlers can be asynchronous; here, we return an empty ValueTask.
        return default;
    }
};

// To keep retrying indefinitely or until success use int.MaxValue.
var optionsIndefiniteRetry = new RetryStrategyOptions
{
    MaxRetryAttempts = int.MaxValue,
};

// Add a retry strategy with a RetryStrategyOptions{<TResult>} instance to the pipeline
new ResiliencePipelineBuilder().AddRetry(optionsDefaults);
new ResiliencePipelineBuilder<HttpResponseMessage>().AddRetry(optionsExtractDelay);

// Circuit breaker with default options.
// See https://www.pollydocs.org/strategies/circuit-breaker#defaults for defaults.
var optionsDefaults = new CircuitBreakerStrategyOptions();

// Circuit breaker with customized options:
// The circuit will break if more than 50% of actions result in handled exceptions,
// within any 10-second sampling duration, and at least 8 actions are processed.
var optionsComplex = new CircuitBreakerStrategyOptions
{
    FailureRatio = 0.5,
    SamplingDuration = TimeSpan.FromSeconds(10),
    MinimumThroughput = 8,
    BreakDuration = TimeSpan.FromSeconds(30),
    ShouldHandle = new PredicateBuilder().Handle<SomeExceptionType>()
};

// Circuit breaker using BreakDurationGenerator:
// The break duration is dynamically determined based on the properties of BreakDurationGeneratorArguments.
var optionsBreakDurationGenerator = new CircuitBreakerStrategyOptions
{
    FailureRatio = 0.5,
    SamplingDuration = TimeSpan.FromSeconds(10),
    MinimumThroughput = 8,
    BreakDurationGenerator = static args => new ValueTask<TimeSpan>(TimeSpan.FromMinutes(args.FailureCount)),
};

// Handle specific failed results for HttpResponseMessage:
var optionsShouldHandle = new CircuitBreakerStrategyOptions<HttpResponseMessage>
{
    ShouldHandle = new PredicateBuilder<HttpResponseMessage>()
        .Handle<SomeExceptionType>()
        .HandleResult(response => response.StatusCode == HttpStatusCode.InternalServerError)
};

// Monitor the circuit state, useful for health reporting:
var stateProvider = new CircuitBreakerStateProvider();
var optionsStateProvider = new CircuitBreakerStrategyOptions<HttpResponseMessage>
{
    StateProvider = stateProvider
};

var circuitState = stateProvider.CircuitState;

/*
CircuitState.Closed - Normal operation; actions are executed.
CircuitState.Open - Circuit is open; actions are blocked.
CircuitState.HalfOpen - Recovery state after break duration expires; actions are permitted.
CircuitState.Isolated - Circuit is manually held open; actions are blocked.
*/

// Manually control the Circuit Breaker state:
var manualControl = new CircuitBreakerManualControl();
var optionsManualControl = new CircuitBreakerStrategyOptions
{
    ManualControl = manualControl
};

// Manually isolate a circuit, e.g., to isolate a downstream service.
await manualControl.IsolateAsync();

// Manually close the circuit to allow actions to be executed again.
await manualControl.CloseAsync();

// Add a circuit breaker strategy with a CircuitBreakerStrategyOptions{<TResult>} instance to the pipeline
new ResiliencePipelineBuilder().AddCircuitBreaker(optionsDefaults);
new ResiliencePipelineBuilder<HttpResponseMessage>().AddCircuitBreaker(optionsStateProvider);

// A fallback/substitute value if an operation fails.
var optionsSubstitute = new FallbackStrategyOptions<UserAvatar>
{
    ShouldHandle = new PredicateBuilder<UserAvatar>()
        .Handle<SomeExceptionType>()
        .HandleResult(r => r is null),
    FallbackAction = static args => Outcome.FromResultAsValueTask(UserAvatar.Blank)
};

// Use a dynamically generated value if an operation fails.
var optionsFallbackAction = new FallbackStrategyOptions<UserAvatar>
{
    ShouldHandle = new PredicateBuilder<UserAvatar>()
        .Handle<SomeExceptionType>()
        .HandleResult(r => r is null),
    FallbackAction = static args =>
    {
        var avatar = UserAvatar.GetRandomAvatar();
        return Outcome.FromResultAsValueTask(avatar);
    }
};

// Use a default or dynamically generated value, and execute an additional action if the fallback is triggered.
var optionsOnFallback = new FallbackStrategyOptions<UserAvatar>
{
    ShouldHandle = new PredicateBuilder<UserAvatar>()
        .Handle<SomeExceptionType>()
        .HandleResult(r => r is null),
    FallbackAction = static args =>
    {
        var avatar = UserAvatar.GetRandomAvatar();
        return Outcome.FromResultAsValueTask(UserAvatar.Blank);
    },
    OnFallback = static args =>
    {
        // Add extra logic to be executed when the fallback is triggered, such as logging.
        return default; // Returns an empty ValueTask
    }
};

// Add a fallback strategy with a FallbackStrategyOptions<TResult> instance to the pipeline
new ResiliencePipelineBuilder<UserAvatar>().AddFallback(optionsOnFallback);

// Hedging with default options.
// See https://www.pollydocs.org/strategies/hedging#defaults for defaults.
var optionsDefaults = new HedgingStrategyOptions<HttpResponseMessage>();

// A customized hedging strategy that retries up to 3 times if the execution
// takes longer than 1 second or if it fails due to an exception or returns an HTTP 500 Internal Server Error.
var optionsComplex = new HedgingStrategyOptions<HttpResponseMessage>
{
    ShouldHandle = new PredicateBuilder<HttpResponseMessage>()
        .Handle<SomeExceptionType>()
        .HandleResult(response => response.StatusCode == HttpStatusCode.InternalServerError),
    MaxHedgedAttempts = 3,
    Delay = TimeSpan.FromSeconds(1),
    ActionGenerator = static args =>
    {
        Console.WriteLine("Preparing to execute hedged action.");

        // Return a delegate function to invoke the original action with the action context.
        // Optionally, you can also create a completely new action to be executed.
        return () => args.Callback(args.ActionContext);
    }
};

// Subscribe to hedging events.
var optionsOnHedging = new HedgingStrategyOptions<HttpResponseMessage>
{
    OnHedging = static args =>
    {
        Console.WriteLine($"OnHedging: Attempt number {args.AttemptNumber}");
        return default;
    }
};

// Add a hedging strategy with a HedgingStrategyOptions<TResult> instance to the pipeline
new ResiliencePipelineBuilder<HttpResponseMessage>().AddHedging(optionsDefaults);

// To add a timeout with a custom TimeSpan duration
new ResiliencePipelineBuilder().AddTimeout(TimeSpan.FromSeconds(3));

// Timeout using the default options.
// See https://www.pollydocs.org/strategies/timeout#defaults for defaults.
var optionsDefaults = new TimeoutStrategyOptions();

// To add a timeout using a custom timeout generator function
var optionsTimeoutGenerator = new TimeoutStrategyOptions
{
    TimeoutGenerator = static args =>
    {
        // Note: the timeout generator supports asynchronous operations
        return new ValueTask<TimeSpan>(TimeSpan.FromSeconds(123));
    }
};

// To add a timeout and listen for timeout events
var optionsOnTimeout = new TimeoutStrategyOptions
{
    TimeoutGenerator = static args =>
    {
        // Note: the timeout generator supports asynchronous operations
        return new ValueTask<TimeSpan>(TimeSpan.FromSeconds(123));
    },
    OnTimeout = static args =>
    {
        Console.WriteLine($"{args.Context.OperationKey}: Execution timed out after {args.Timeout.TotalSeconds} seconds.");
        return default;
    }
};

// Add a timeout strategy with a TimeoutStrategyOptions instance to the pipeline
new ResiliencePipelineBuilder().AddTimeout(optionsDefaults);

// Add rate limiter with default options.
// See https://www.pollydocs.org/strategies/rate-limiter#defaults for defaults.
new ResiliencePipelineBuilder()
    .AddRateLimiter(new RateLimiterStrategyOptions());

// Create a rate limiter to allow a maximum of 100 concurrent executions and a queue of 50.
new ResiliencePipelineBuilder()
    .AddConcurrencyLimiter(100, 50);

// Create a rate limiter that allows 100 executions per minute.
new ResiliencePipelineBuilder()
    .AddRateLimiter(new SlidingWindowRateLimiter(
        new SlidingWindowRateLimiterOptions
        {
            PermitLimit = 100,
            Window = TimeSpan.FromMinutes(1)
        }));