Initial structure of costByTag command

src/Commands/CostByTag/CostByTagCommand.cs

@@ -0,0 +1,146 @@
+using System.Diagnostics;
+using System.Text.Json;
+using AzureCostCli.Commands.ShowCommand;
+using AzureCostCli.Commands.ShowCommand.OutputFormatters;
+using AzureCostCli.CostApi;
+using AzureCostCli.Infrastructure;
+using Spectre.Console;
+using Spectre.Console.Cli;
+
+namespace AzureCostCli.Commands.CostByResource;
+
+public class CostByTagCommand : AsyncCommand<CostByTagSettings>
+{
+    private readonly ICostRetriever _costRetriever;
+
+    private readonly Dictionary<OutputFormat, BaseOutputFormatter> _outputFormatters = new();
+
+    public CostByTagCommand(ICostRetriever costRetriever)
+    {
+        _costRetriever = costRetriever;
+
+        // Add the output formatters
+        _outputFormatters.Add(OutputFormat.Console, new ConsoleOutputFormatter());
+        _outputFormatters.Add(OutputFormat.Json, new JsonOutputFormatter());
+        _outputFormatters.Add(OutputFormat.Jsonc, new JsonOutputFormatter());
+        _outputFormatters.Add(OutputFormat.Text, new TextOutputFormatter());
+        _outputFormatters.Add(OutputFormat.Markdown, new MarkdownOutputFormatter());
+        _outputFormatters.Add(OutputFormat.Csv, new CsvOutputFormatter());
+    }
+
+    public override ValidationResult Validate(CommandContext context, CostByTagSettings settings)
+    {
+        // Validate if the timeframe is set to Custom, then the from and to dates must be specified and the from date must be before the to date
+        if (settings.Timeframe == TimeframeType.Custom)
+        {
+            if (settings.From == null)
+            {
+                return ValidationResult.Error("The from date must be specified when the timeframe is set to Custom.");
+            }
+
+            if (settings.To == null)
+            {
+                return ValidationResult.Error("The to date must be specified when the timeframe is set to Custom.");
+            }
+
+            if (settings.From > settings.To)
+            {
+                return ValidationResult.Error("The from date must be before the to date.");
+            }
+        }
+
+        return ValidationResult.Success();
+    }
+
+    public override async Task<int> ExecuteAsync(CommandContext context, CostByTagSettings settings)
+    {
+        // Show version
+        if (settings.Debug)
+            AnsiConsole.WriteLine($"Version: {typeof(CostByResourceCommand).Assembly.GetName().Version}");
+
+
+        // Get the subscription ID from the settings
+        var subscriptionId = settings.Subscription;
+
+        if (subscriptionId == Guid.Empty)
+        {
+            // Get the subscription ID from the Azure CLI
+            try
+            {
+                if (settings.Debug)
+                    AnsiConsole.WriteLine(
+                        "No subscription ID specified. Trying to retrieve the default subscription ID from Azure CLI.");
+
+                subscriptionId = Guid.Parse(AzCommand.GetDefaultAzureSubscriptionId());
+
+                if (settings.Debug)
+                    AnsiConsole.WriteLine($"Default subscription ID retrieved from az cli: {subscriptionId}");
+
+                settings.Subscription = subscriptionId;
+            }
+            catch (Exception e)
+            {
+                AnsiConsole.WriteException(new ArgumentException(
+                    "Missing subscription ID. Please specify a subscription ID or login to Azure CLI.", e));
+                return -1;
+            }
+        }
+
+        // Fetch the costs from the Azure Cost Management API
+        IEnumerable<CostResourceItem> resources = new List<CostResourceItem>();
+
+        await AnsiConsole.Status()
+            .StartAsync("Fetching cost data for resources...", async ctx =>
+            {
+                resources = await _costRetriever.RetrieveCostForResources(
+                    settings.Debug,
+                    subscriptionId, settings.Filter,
+                    settings.Metric,
+                    true,
+                    settings.Timeframe,
+                    settings.From,
+                    settings.To);
+            });
+
+        var byTags = GetResourcesByTag(resources, settings.Tags.ToArray());
+
+        // Write the output
+        await _outputFormatters[settings.Output]
+            .WriteCostByTag(settings, byTags);
+
+        return 0;
+    }
+
+    private Dictionary<string, Dictionary<string, List<CostResourceItem>>> GetResourcesByTag(
+        IEnumerable<CostResourceItem> resources, params string[] tags)
+    {
+        var resourcesByTag =
+            new Dictionary<string, Dictionary<string, List<CostResourceItem>>>(StringComparer.OrdinalIgnoreCase);
+
+        foreach (var tag in tags)
+        {
+            resourcesByTag[tag] = new Dictionary<string, List<CostResourceItem>>(StringComparer.OrdinalIgnoreCase);
+        }
+
+        foreach (var resource in resources)
+        {
+            foreach (var tag in tags)
+            {
+                var resourceTags = new Dictionary<string, string>(resource.Tags, StringComparer.OrdinalIgnoreCase);
+
+                if (resourceTags.ContainsKey(tag))
+                {
+                    var tagValue = resourceTags[tag];
+                    if (!resourcesByTag[tag].ContainsKey(tagValue))
+                    {
+                        resourcesByTag[tag][tagValue] = new List<CostResourceItem>();
+                    }
+
+                    resourcesByTag[tag][tagValue].Add(resource);
+                }
+            }
+        }
+
+        return resourcesByTag;
+    }
+}

src/Commands/CostByTag/CostByTagSettings.cs

@@ -0,0 +1,12 @@
+using System.ComponentModel;
+using Spectre.Console.Cli;
+
+namespace AzureCostCli.Commands.ShowCommand;
+
+public class CostByTagSettings : CostSettings
+{
+
+    [CommandOption("--tag")]
+    [Description("The tags to return, for example: Cost Center or Owner. You can specify multiple tags by using the --tag option multiple times.")]
+    public string[] Tags { get; set; } = Array.Empty<string>();
+}

src/OutputFormatters/BaseOutputFormatter.cs

@@ -14,6 +14,7 @@ public abstract class BaseOutputFormatter
     public abstract Task WriteDailyCost(DailyCostSettings settings, IEnumerable<CostDailyItem> dailyCosts);
     public abstract Task WriteAnomalyDetectionResults(DetectAnomalySettings settings, List<AnomalyDetectionResult> anomalies);
     public abstract Task WriteRegions(RegionsSettings settings, IReadOnlyCollection<AzureRegion> regions);
+    public abstract Task WriteCostByTag(CostByTagSettings settings, Dictionary<string, Dictionary<string, List<CostResourceItem>>> byTags);
 }
 
 public record AccumulatedCostDetails( 

src/OutputFormatters/ConsoleOutputFormatter.cs

@@ -521,5 +521,10 @@ public override Task WriteRegions(RegionsSettings settings, IReadOnlyCollection<
 
         return Task.CompletedTask;
     }
+
+    public override Task WriteCostByTag(CostByTagSettings settings, Dictionary<string, Dictionary<string, List<CostResourceItem>>> byTags)
+    {
+        throw new NotImplementedException();
+    }
 }
 

src/OutputFormatters/CsvOutputFormatter.cs

@@ -40,6 +40,36 @@ public override Task WriteRegions(RegionsSettings settings, IReadOnlyCollection<
         return ExportToCsv(settings.SkipHeader, regions);
     }
 
+    public override Task WriteCostByTag(CostByTagSettings settings, Dictionary<string, Dictionary<string, List<CostResourceItem>>> byTags)
+    {
+        // Flatten the hierarchy to a single list, including the tag and value
+        var resourcesWithTagAndValue = new List<dynamic>();
+        foreach (var (tag, value) in byTags)
+        {
+            foreach (var (tagValue, resources) in value)
+            {
+                foreach (var resource in resources)
+                {
+                    dynamic expando = new ExpandoObject();
+                    expando.Tag = tag;
+                    expando.Value = tagValue;
+                    expando.ResourceId = resource.ResourceId;
+                    expando.ResourceType = resource.ResourceType;
+                    expando.ResourceGroup = resource.ResourceGroupName;
+                    expando.ResourceLocation = resource.ResourceLocation;
+                    expando.Cost = resource.Cost;
+                    expando.Currency = resource.Currency;
+                    expando.CostUsd = resource.CostUSD;
+
+                    resourcesWithTagAndValue.Add(expando);
+                }
+            }
+        }
+
+
+        return ExportToCsv(settings.SkipHeader, resourcesWithTagAndValue);
+    }
+
     private static Task ExportToCsv(bool skipHeader, IEnumerable<object> resources)
     {
         var config = new CsvConfiguration(CultureInfo.CurrentCulture)

src/OutputFormatters/JsonOutputFormatter.cs

@@ -83,7 +83,14 @@ public override Task WriteRegions(RegionsSettings settings, IReadOnlyCollection<
 
         return Task.CompletedTask;
     }
-
+
+    public override Task WriteCostByTag(CostByTagSettings settings, Dictionary<string, Dictionary<string, List<CostResourceItem>>> byTags)
+    {
+        WriteJson(settings, byTags);
+
+        return Task.CompletedTask;
+    }
+
 
     private static void WriteJson(CostSettings settings, object items)
     {

src/OutputFormatters/MarkdownOutputFormatter.cs

@@ -328,4 +328,9 @@ public override Task WriteRegions(RegionsSettings settings, IReadOnlyCollection<
     {
         throw new NotImplementedException();
     }
+
+    public override Task WriteCostByTag(CostByTagSettings settings, Dictionary<string, Dictionary<string, List<CostResourceItem>>> byTags)
+    {
+        throw new NotImplementedException();
+    }
 }

src/OutputFormatters/TextOutputFormatter.cs

@@ -210,4 +210,9 @@ public override Task WriteRegions(RegionsSettings settings, IReadOnlyCollection<
     {
         throw new NotImplementedException();
     }
+
+    public override Task WriteCostByTag(CostByTagSettings settings, Dictionary<string, Dictionary<string, List<CostResourceItem>>> byTags)
+    {
+        throw new NotImplementedException();
+    }
 }

src/Program.cs

@@ -64,6 +64,9 @@
   
   config.AddCommand<CostByResourceCommand>("costByResource")
     .WithDescription("Show the cost details by resource.");
+
+  config.AddCommand<CostByTagCommand>("costByTag")
+    .WithDescription("Show the cost details by tag.");
   
   config.AddCommand<DetectAnomalyCommand>("detectAnomalies")
     .WithDescription("Detect anomalies and trends.");