// 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.IO;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.Storage;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.Host
{
    internal abstract class AbstractPersistentStorage : IChecksummedPersistentStorage
    {
        public string WorkingFolderPath { get; }
        public string SolutionFilePath { get; }
 
        public string DatabaseFile { get; }
        public string DatabaseDirectory => Path.GetDirectoryName(DatabaseFile) ?? throw ExceptionUtilities.UnexpectedValue(DatabaseFile);
 
        private bool _isDisabled;
 
        protected AbstractPersistentStorage(
            string workingFolderPath,
            string solutionFilePath,
            string databaseFile)
        {
            this.WorkingFolderPath = workingFolderPath;
            this.SolutionFilePath = solutionFilePath;
            this.DatabaseFile = databaseFile;
 
            if (!Directory.Exists(this.DatabaseDirectory))
            {
                Directory.CreateDirectory(this.DatabaseDirectory);
            }
        }
 
        private bool IsDisabled
            => Volatile.Read(ref _isDisabled);
 
        protected void DisableStorage()
            => Volatile.Write(ref _isDisabled, true);
 
        public abstract void Dispose();
        public abstract ValueTask DisposeAsync();
 
        public abstract Task<bool> ChecksumMatchesAsync(string name, Checksum checksum, CancellationToken cancellationToken);
        public abstract Task<Stream?> ReadStreamAsync(string name, Checksum? checksum, CancellationToken cancellationToken);
        public abstract Task<bool> WriteStreamAsync(string name, Stream stream, Checksum? checksum, CancellationToken cancellationToken);
 
        protected abstract Task<bool> ChecksumMatchesAsync(ProjectKey projectKey, Project? project, string name, Checksum checksum, CancellationToken cancellationToken);
        protected abstract Task<bool> ChecksumMatchesAsync(DocumentKey documentKey, Document? document, string name, Checksum checksum, CancellationToken cancellationToken);
        protected abstract Task<Stream?> ReadStreamAsync(ProjectKey projectKey, Project? project, string name, Checksum? checksum, CancellationToken cancellationToken);
        protected abstract Task<Stream?> ReadStreamAsync(DocumentKey documentKey, Document? document, string name, Checksum? checksum, CancellationToken cancellationToken);
        protected abstract Task<bool> WriteStreamAsync(ProjectKey projectKey, Project? project, string name, Stream stream, Checksum? checksum, CancellationToken cancellationToken);
        protected abstract Task<bool> WriteStreamAsync(DocumentKey documentKey, Document? document, string name, Stream stream, Checksum? checksum, CancellationToken cancellationToken);
 
        public Task<bool> ChecksumMatchesAsync(ProjectKey projectKey, string name, Checksum checksum, CancellationToken cancellationToken)
            => IsDisabled ? SpecializedTasks.False : ChecksumMatchesAsync(projectKey, project: null, name, checksum, cancellationToken);
 
        public Task<bool> ChecksumMatchesAsync(DocumentKey documentKey, string name, Checksum checksum, CancellationToken cancellationToken)
            => IsDisabled ? SpecializedTasks.False : ChecksumMatchesAsync(documentKey, document: null, name, checksum, cancellationToken);
 
        public Task<Stream?> ReadStreamAsync(ProjectKey projectKey, string name, Checksum? checksum, CancellationToken cancellationToken)
            => IsDisabled ? SpecializedTasks.Null<Stream>() : ReadStreamAsync(projectKey, project: null, name, checksum, cancellationToken);
 
        public Task<Stream?> ReadStreamAsync(DocumentKey documentKey, string name, Checksum? checksum, CancellationToken cancellationToken)
            => IsDisabled ? SpecializedTasks.Null<Stream>() : ReadStreamAsync(documentKey, document: null, name, checksum, cancellationToken);
 
        public Task<bool> WriteStreamAsync(ProjectKey projectKey, string name, Stream stream, Checksum? checksum, CancellationToken cancellationToken)
            => IsDisabled ? SpecializedTasks.False : WriteStreamAsync(projectKey, project: null, name, stream, checksum, cancellationToken);
 
        public Task<bool> WriteStreamAsync(DocumentKey documentKey, string name, Stream stream, Checksum? checksum, CancellationToken cancellationToken)
            => IsDisabled ? SpecializedTasks.False : WriteStreamAsync(documentKey, document: null, name, stream, checksum, cancellationToken);
 
        public Task<bool> ChecksumMatchesAsync(Project project, string name, Checksum checksum, CancellationToken cancellationToken)
            => IsDisabled ? SpecializedTasks.False : ChecksumMatchesAsync(ProjectKey.ToProjectKey(project), project, name, checksum, cancellationToken);
 
        public Task<bool> ChecksumMatchesAsync(Document document, string name, Checksum checksum, CancellationToken cancellationToken)
            => IsDisabled ? SpecializedTasks.False : ChecksumMatchesAsync(DocumentKey.ToDocumentKey(document), document, name, checksum, cancellationToken);
 
        public Task<Stream?> ReadStreamAsync(Project project, string name, Checksum? checksum, CancellationToken cancellationToken)
            => IsDisabled ? SpecializedTasks.Null<Stream>() : ReadStreamAsync(ProjectKey.ToProjectKey(project), project, name, checksum, cancellationToken);
 
        public Task<Stream?> ReadStreamAsync(Document document, string name, Checksum? checksum, CancellationToken cancellationToken)
            => IsDisabled ? SpecializedTasks.Null<Stream>() : ReadStreamAsync(DocumentKey.ToDocumentKey(document), document, name, checksum, cancellationToken);
 
        public Task<Stream?> ReadStreamAsync(string name, CancellationToken cancellationToken)
            => IsDisabled ? SpecializedTasks.Null<Stream>() : ReadStreamAsync(name, checksum: null, cancellationToken);
 
        public Task<Stream?> ReadStreamAsync(Project project, string name, CancellationToken cancellationToken)
            => IsDisabled ? SpecializedTasks.Null<Stream>() : ReadStreamAsync(project, name, checksum: null, cancellationToken);
 
        public Task<Stream?> ReadStreamAsync(Document document, string name, CancellationToken cancellationToken)
            => IsDisabled ? SpecializedTasks.Null<Stream>() : ReadStreamAsync(document, name, checksum: null, cancellationToken);
 
        public Task<bool> WriteStreamAsync(Project project, string name, Stream stream, Checksum? checksum, CancellationToken cancellationToken)
            => IsDisabled ? SpecializedTasks.False : WriteStreamAsync(ProjectKey.ToProjectKey(project), project, name, stream, checksum, cancellationToken);
 
        public Task<bool> WriteStreamAsync(Document document, string name, Stream stream, Checksum? checksum, CancellationToken cancellationToken)
            => IsDisabled ? SpecializedTasks.False : WriteStreamAsync(DocumentKey.ToDocumentKey(document), document, name, stream, checksum, cancellationToken);
 
        public Task<bool> WriteStreamAsync(string name, Stream stream, CancellationToken cancellationToken)
            => IsDisabled ? SpecializedTasks.False : WriteStreamAsync(name, stream, checksum: null, cancellationToken);
 
        public Task<bool> WriteStreamAsync(Project project, string name, Stream stream, CancellationToken cancellationToken)
            => IsDisabled ? SpecializedTasks.False : WriteStreamAsync(project, name, stream, checksum: null, cancellationToken);
 
        public Task<bool> WriteStreamAsync(Document document, string name, Stream stream, CancellationToken cancellationToken)
            => IsDisabled ? SpecializedTasks.False : WriteStreamAsync(document, name, stream, checksum: null, cancellationToken);
    }
}