//===--------------------- ModuleCache.cpp ----------------------*- C++ -*-===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#include "ModuleCache.h"

#include "lldb/Core/Module.h"
#include "lldb/Host/FileSystem.h"
#include "llvm/Support/FileSystem.h"

#include <assert.h>

#include <cstdio>
#
using namespace lldb;
using namespace lldb_private;

namespace {

const char* kModulesSubdir = ".cache";

FileSpec
JoinPath (const FileSpec &path1, const char* path2)
{
    FileSpec result_spec (path1);
    result_spec.AppendPathComponent (path2);
    return result_spec;
}

Error
MakeDirectory (const FileSpec &dir_path)
{
    if (dir_path.Exists ())
    {
        if (!dir_path.IsDirectory ())
            return Error ("Invalid existing path");

        return Error ();
    }

    return FileSystem::MakeDirectory (dir_path.GetPath ().c_str (),
                                      eFilePermissionsDirectoryDefault);
}

}  // namespace

Error
ModuleCache::Put (const FileSpec &root_dir_spec,
                  const char *hostname,
                  const UUID &uuid,
                  const FileSpec &platform_module_spec,
                  const FileSpec &tmp_file)
{
    const auto module_spec_dir = GetModuleDirectory (root_dir_spec, uuid);
    auto error = MakeDirectory (module_spec_dir);
    if (error.Fail ())
        return error;

    const auto module_file_path = JoinPath (module_spec_dir, platform_module_spec.GetFilename ().AsCString ());

    const auto tmp_file_path = tmp_file.GetPath ();
    const auto err_code = llvm::sys::fs::copy_file (tmp_file_path.c_str (), module_file_path.GetPath ().c_str ());
    if (err_code)
    {
        error.SetErrorStringWithFormat ("failed to copy file %s to %s: %s",
                                        tmp_file_path.c_str (),
                                        module_file_path.GetPath ().c_str (),
                                        err_code.message ().c_str ());
    }

    // Create sysroot link to a module.
    const auto sysroot_module_path_spec = GetHostSysRootModulePath (root_dir_spec, hostname, platform_module_spec);
    return CreateHostSysRootModuleSymLink (sysroot_module_path_spec, module_file_path);
}

Error
ModuleCache::Get (const FileSpec &root_dir_spec,
                  const char *hostname,
                  const UUID &uuid,
                  const FileSpec &platform_module_spec,
                  FileSpec &cached_module_spec)
{
    cached_module_spec.Clear ();

    const auto module_spec_dir = GetModuleDirectory (root_dir_spec, uuid);
    const auto module_file_path = JoinPath (module_spec_dir, platform_module_spec.GetFilename ().AsCString ());

    Error error;
    if (!module_file_path.Exists ())
    {
        error.SetErrorStringWithFormat ("module %s not found", module_file_path.GetPath ().c_str ());
        return error;
    }
    cached_module_spec = module_file_path;

    // We may have already cached module but downloaded from an another host - in this case let's create a symlink to it.
    const auto sysroot_module_path_spec = GetHostSysRootModulePath (root_dir_spec, hostname, platform_module_spec);
    if (!sysroot_module_path_spec.Exists ())
        CreateHostSysRootModuleSymLink (sysroot_module_path_spec, cached_module_spec);

    return error;
}

FileSpec
ModuleCache::GetModuleDirectory (const FileSpec &root_dir_spec, const UUID &uuid)
{
    const auto modules_dir_spec = JoinPath (root_dir_spec, kModulesSubdir);
    return JoinPath (modules_dir_spec, uuid.GetAsString ().c_str ());
}

FileSpec
ModuleCache::GetHostSysRootModulePath (const FileSpec &root_dir_spec, const char *hostname, const FileSpec &platform_module_spec)
{
    const auto sysroot_dir = JoinPath (root_dir_spec, hostname);
    return JoinPath (sysroot_dir, platform_module_spec.GetPath ().c_str ());
}

Error
ModuleCache::CreateHostSysRootModuleSymLink (const FileSpec &sysroot_module_path_spec, const FileSpec &module_file_path)
{
    const auto error = MakeDirectory (FileSpec (sysroot_module_path_spec.GetDirectory ().AsCString (), false));
    if (error.Fail ())
        return error;

    return FileSystem::Symlink (sysroot_module_path_spec.GetPath ().c_str (),
                                module_file_path.GetPath ().c_str ());
}