// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
 
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Diagnostics;
using System.Linq;
using Microsoft.CodeAnalysis.CodeActions;
using Microsoft.CodeAnalysis.CodeFixesAndRefactorings;
using Microsoft.CodeAnalysis.Text;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.CodeFixes
{
    internal sealed partial class FixAllState : CommonFixAllState<CodeFixProvider, FixAllProvider, FixAllState>
    {
        public override FixAllKind FixAllKind => FixAllKind.CodeFix;
 
        public FixAllContext.DiagnosticProvider DiagnosticProvider { get; }
 
        public ImmutableHashSet<string> DiagnosticIds { get; }
 
        // Note: DiagnosticSpan can be null from the back-compat public constructor of FixAllContext.
        public TextSpan? DiagnosticSpan { get; }
 
        internal FixAllState(
            FixAllProvider fixAllProvider,
            TextSpan? diagnosticSpan,
            Document? document,
            Project project,
            CodeFixProvider codeFixProvider,
            FixAllScope scope,
            string? codeActionEquivalenceKey,
            IEnumerable<string> diagnosticIds,
            FixAllContext.DiagnosticProvider fixAllDiagnosticProvider,
            CodeActionOptionsProvider codeActionOptionsProvider)
            : base(fixAllProvider, document, project, codeFixProvider, codeActionOptionsProvider, scope, codeActionEquivalenceKey)
        {
            // We need the trigger diagnostic span for span based fix all scopes, i.e. FixAllScope.ContainingMember and FixAllScope.ContainingType
            Debug.Assert(diagnosticSpan.HasValue || scope is not FixAllScope.ContainingMember or FixAllScope.ContainingType);
 
            DiagnosticSpan = diagnosticSpan;
            DiagnosticIds = ImmutableHashSet.CreateRange(diagnosticIds);
            DiagnosticProvider = fixAllDiagnosticProvider;
        }
 
        internal bool IsFixMultiple => DiagnosticProvider is FixMultipleDiagnosticProvider;
 
        protected override FixAllState With(Document? document, Project project, FixAllScope scope, string? codeActionEquivalenceKey)
            => new(
                FixAllProvider,
                DiagnosticSpan,
                document,
                project,
                Provider,
                scope,
                codeActionEquivalenceKey,
                DiagnosticIds,
                DiagnosticProvider,
                CodeActionOptionsProvider);
 
        #region FixMultiple
 
        internal static FixAllState Create(
            FixAllProvider fixAllProvider,
            ImmutableDictionary<Document, ImmutableArray<Diagnostic>> diagnosticsToFix,
            CodeFixProvider codeFixProvider,
            string? codeActionEquivalenceKey,
            CodeActionOptionsProvider codeActionOptionsProvider)
        {
            var triggerDocument = diagnosticsToFix.First().Key;
            var diagnosticSpan = diagnosticsToFix.First().Value.FirstOrDefault()?.Location.SourceSpan;
            var diagnosticIds = GetDiagnosticsIds(diagnosticsToFix.Values);
            var diagnosticProvider = new FixMultipleDiagnosticProvider(diagnosticsToFix);
            return new FixAllState(
                fixAllProvider,
                diagnosticSpan,
                triggerDocument,
                triggerDocument.Project,
                codeFixProvider,
                FixAllScope.Custom,
                codeActionEquivalenceKey,
                diagnosticIds,
                diagnosticProvider,
                codeActionOptionsProvider);
        }
 
        internal static FixAllState Create(
            FixAllProvider fixAllProvider,
            ImmutableDictionary<Project, ImmutableArray<Diagnostic>> diagnosticsToFix,
            CodeFixProvider codeFixProvider,
            string? codeActionEquivalenceKey,
            CodeActionOptionsProvider codeActionOptionsProvider)
        {
            var triggerProject = diagnosticsToFix.First().Key;
            var diagnosticIds = GetDiagnosticsIds(diagnosticsToFix.Values);
            var diagnosticProvider = new FixMultipleDiagnosticProvider(diagnosticsToFix);
            return new FixAllState(
                fixAllProvider,
                diagnosticSpan: null,
                document: null,
                triggerProject,
                codeFixProvider,
                FixAllScope.Custom,
                codeActionEquivalenceKey,
                diagnosticIds,
                diagnosticProvider,
                codeActionOptionsProvider);
        }
 
        private static ImmutableHashSet<string> GetDiagnosticsIds(IEnumerable<ImmutableArray<Diagnostic>> diagnosticsCollection)
        {
            var uniqueIds = ImmutableHashSet.CreateBuilder<string>();
            foreach (var diagnostics in diagnosticsCollection)
            {
                foreach (var diagnostic in diagnostics)
                {
                    uniqueIds.Add(diagnostic.Id);
                }
            }
 
            return uniqueIds.ToImmutable();
        }
 
        #endregion
    }
}