// Copyright 2017-2018 ccls Authors
// SPDX-License-Identifier: Apache-2.0

#include "filesystem.hh"
#include "include_complete.hh"
#include "log.hh"
#include "message_handler.hh"
#include "pipeline.hh"
#include "platform.hh"
#include "project.hh"
#include "sema_manager.hh"
#include "working_files.hh"

#include <llvm/ADT/Twine.h>
#include <llvm/Config/llvm-config.h>
#include <llvm/Support/Threading.h>

#include <rapidjson/document.h>
#include <rapidjson/writer.h>

#include <stdexcept>
#include <stdlib.h>
#include <thread>

namespace ccls {
using namespace llvm;

std::vector<const char *> SEMANTIC_TOKENS = {
  "unknown",

  "file",
  "module",
  "namespace",
  "package",
  "class",
  "method",
  "property",
  "field",
  "constructor",
  "enum",
  "interface",
  "function",
  "variable",
  "constant",
  "string",
  "number",
  "boolean",
  "array",
  "object",
  "key",
  "null",
  "enumMember",
  "struct",
  "event",
  "operator",
  "typeParameter",
  "typeAlias", //252 => 27
  "parameter",
  "staticMethod",
  "macro"
};

std::vector<const char *> SEMANTIC_MODIFIERS = {
    "declaration", //1
    "definition",  //2
    "static"       //4
};

extern std::vector<std::string> g_init_options;

namespace {
enum class TextDocumentSyncKind { None = 0, Full = 1, Incremental = 2 };
REFLECT_UNDERLYING(TextDocumentSyncKind)

bool didChangeWatchedFiles;

struct ServerCap {
  struct SaveOptions {
    bool includeText = false;
  };
  struct TextDocumentSyncOptions {
    bool openClose = true;
    TextDocumentSyncKind change = TextDocumentSyncKind::Incremental;
    bool willSave = false;
    bool willSaveWaitUntil = false;
    SaveOptions save;
  } textDocumentSync;

  // The server provides hover support.
  bool hoverProvider = true;
  struct CompletionOptions {
    bool resolveProvider = false;

    // The characters that trigger completion automatically.
    // vscode doesn't support trigger character sequences, so we use ':'
    // for
    // '::' and '>' for '->'. See
    // https://github.com/Microsoft/language-server-protocol/issues/138.
    std::vector<const char *> triggerCharacters = {".", ":",  ">", "#",
                                                   "<", "\"", "/"};
  } completionProvider;
  struct SignatureHelpOptions {
    std::vector<const char *> triggerCharacters = {"(", ","};
  } signatureHelpProvider;
  bool declarationProvider = true;
  bool definitionProvider = true;
  bool typeDefinitionProvider = true;
  bool implementationProvider = true;
  bool referencesProvider = true;
  bool documentHighlightProvider = true;
  bool documentSymbolProvider = true;
  bool workspaceSymbolProvider = true;
  struct CodeActionOptions {
    std::vector<const char *> codeActionKinds = {"quickfix"};
  } codeActionProvider;
  struct CodeLensOptions {
    bool resolveProvider = false;
  } codeLensProvider;
  bool documentFormattingProvider = true;
  bool documentRangeFormattingProvider = true;
  Config::ServerCap::DocumentOnTypeFormattingOptions
      documentOnTypeFormattingProvider;
  bool renameProvider = true;
  struct DocumentLinkOptions {
    bool resolveProvider = true;
  } documentLinkProvider;
  bool foldingRangeProvider = true;
  // The server provides execute command support.
  struct ExecuteCommandOptions {
    std::vector<const char *> commands = {ccls_xref};
  } executeCommandProvider;
  Config::ServerCap::Workspace workspace;
  struct SemanticTokenProvider {
      struct SemanticTokensLegend {
          std::vector<const char *> tokenTypes = SEMANTIC_TOKENS;
          std::vector<const char *> tokenModifiers = SEMANTIC_MODIFIERS;
      } legend;
      bool full = true;
  } semanticTokensProvider;
};
REFLECT_STRUCT(ServerCap::CodeActionOptions, codeActionKinds);
REFLECT_STRUCT(ServerCap::CodeLensOptions, resolveProvider);
REFLECT_STRUCT(ServerCap::CompletionOptions, resolveProvider,
               triggerCharacters);
REFLECT_STRUCT(ServerCap::DocumentLinkOptions, resolveProvider);
REFLECT_STRUCT(ServerCap::ExecuteCommandOptions, commands);
REFLECT_STRUCT(ServerCap::SaveOptions, includeText);
REFLECT_STRUCT(ServerCap::SignatureHelpOptions, triggerCharacters);
REFLECT_STRUCT(ServerCap::TextDocumentSyncOptions, openClose, change, willSave,
               willSaveWaitUntil, save);
REFLECT_STRUCT(ServerCap, textDocumentSync, hoverProvider, completionProvider,
               signatureHelpProvider, declarationProvider, definitionProvider,
               implementationProvider, typeDefinitionProvider,
               referencesProvider, documentHighlightProvider,
               documentSymbolProvider, workspaceSymbolProvider,
               codeActionProvider, codeLensProvider, documentFormattingProvider,
               documentRangeFormattingProvider,
               documentOnTypeFormattingProvider, renameProvider,
               documentLinkProvider, foldingRangeProvider,
               executeCommandProvider, workspace, semanticTokensProvider);
REFLECT_STRUCT(ServerCap::SemanticTokenProvider, legend, full);
REFLECT_STRUCT(ServerCap::SemanticTokenProvider::SemanticTokensLegend, tokenTypes, tokenModifiers);

struct DynamicReg {
  bool dynamicRegistration = false;
};
REFLECT_STRUCT(DynamicReg, dynamicRegistration);

// Workspace specific client capabilities.
struct WorkspaceClientCap {
  // The client supports applying batch edits to the workspace.
  std::optional<bool> applyEdit;

  struct WorkspaceEdit {
    // The client supports versioned document changes in `WorkspaceEdit`s
    std::optional<bool> documentChanges;
  };

  // Capabilities specific to `WorkspaceEdit`s
  std::optional<WorkspaceEdit> workspaceEdit;
  DynamicReg didChangeConfiguration;
  DynamicReg didChangeWatchedFiles;
  DynamicReg symbol;
  DynamicReg executeCommand;
};

REFLECT_STRUCT(WorkspaceClientCap::WorkspaceEdit, documentChanges);
REFLECT_STRUCT(WorkspaceClientCap, applyEdit, workspaceEdit,
               didChangeConfiguration, didChangeWatchedFiles, symbol,
               executeCommand);

// Text document specific client capabilities.
struct TextDocumentClientCap {
  struct Completion {
    struct CompletionItem {
      // Client supports snippets as insert text.
      //
      // A snippet can define tab stops and placeholders with `$1`, `$2`
      // and `${3:foo}`. `$0` defines the final tab stop, it defaults to
      // the end of the snippet. Placeholders with equal identifiers are linked,
      // that is typing in one will update others too.
      bool snippetSupport = false;
    } completionItem;
  } completion;

  // Ignore declaration, implementation, typeDefinition
  struct LinkSupport {
    bool linkSupport = false;
  } definition;

  struct DocumentSymbol {
    bool hierarchicalDocumentSymbolSupport = false;
  } documentSymbol;

  struct PublishDiagnostics {
    bool relatedInformation = false;
  } publishDiagnostics;
};

REFLECT_STRUCT(TextDocumentClientCap::Completion::CompletionItem,
               snippetSupport);
REFLECT_STRUCT(TextDocumentClientCap::Completion, completionItem);
REFLECT_STRUCT(TextDocumentClientCap::DocumentSymbol,
               hierarchicalDocumentSymbolSupport);
REFLECT_STRUCT(TextDocumentClientCap::LinkSupport, linkSupport);
REFLECT_STRUCT(TextDocumentClientCap::PublishDiagnostics, relatedInformation);
REFLECT_STRUCT(TextDocumentClientCap, completion, definition, documentSymbol,
               publishDiagnostics);

struct ClientCap {
  WorkspaceClientCap workspace;
  TextDocumentClientCap textDocument;
};
REFLECT_STRUCT(ClientCap, workspace, textDocument);

struct InitializeParam {
  // The rootUri of the workspace. Is null if no
  // folder is open. If both `rootPath` and `rootUri` are set
  // `rootUri` wins.
  std::optional<DocumentUri> rootUri;

  Config initializationOptions;
  ClientCap capabilities;

  enum class Trace {
    // NOTE: serialized as a string, one of 'off' | 'messages' | 'verbose';
    Off,      // off
    Messages, // messages
    Verbose   // verbose
  };
  Trace trace = Trace::Off;

  std::vector<WorkspaceFolder> workspaceFolders;
};

void reflect(JsonReader &reader, InitializeParam::Trace &value) {
  if (!reader.m->IsString()) {
    value = InitializeParam::Trace::Off;
    return;
  }
  std::string v = reader.m->GetString();
  if (v == "off")
    value = InitializeParam::Trace::Off;
  else if (v == "messages")
    value = InitializeParam::Trace::Messages;
  else if (v == "verbose")
    value = InitializeParam::Trace::Verbose;
}

// initializationOptions is deserialized separately.
REFLECT_STRUCT(InitializeParam, rootUri, capabilities, trace, workspaceFolders);

struct InitializeResult {
  ServerCap capabilities;
  struct ServerInfo {
    const char *name = "ccls";
    const char *version = CCLS_VERSION;
  } serverInfo;
};
REFLECT_STRUCT(InitializeResult::ServerInfo, name, version);
REFLECT_STRUCT(InitializeResult, capabilities, serverInfo);

struct FileSystemWatcher {
  std::string globPattern = "**/*";
};
struct DidChangeWatchedFilesRegistration {
  std::string id = "didChangeWatchedFiles";
  std::string method = "workspace/didChangeWatchedFiles";
  struct Option {
    std::vector<FileSystemWatcher> watchers = {{}};
  } registerOptions;
};
struct RegistrationParam {
  std::vector<DidChangeWatchedFilesRegistration> registrations = {{}};
};
REFLECT_STRUCT(FileSystemWatcher, globPattern);
REFLECT_STRUCT(DidChangeWatchedFilesRegistration::Option, watchers);
REFLECT_STRUCT(DidChangeWatchedFilesRegistration, id, method, registerOptions);
REFLECT_STRUCT(RegistrationParam, registrations);

void *indexer(void *arg_) {
  MessageHandler *h;
  int idx;
  auto *arg = static_cast<std::pair<MessageHandler *, int> *>(arg_);
  std::tie(h, idx) = *arg;
  delete arg;
  std::string name = "indexer" + std::to_string(idx);
  set_thread_name(name.c_str());
  // Don't lower priority on __APPLE__. getpriority(2) says "When setting a
  // thread into background state the scheduling priority is set to lowest
  // value, disk and network IO are throttled."
#if LLVM_ENABLE_THREADS && LLVM_VERSION_MAJOR >= 9 && !defined(__APPLE__)
  set_thread_priority(ThreadPriority::Background);
#endif
  pipeline::indexer_Main(h->manager, h->vfs, h->project, h->wfiles);
  pipeline::threadLeave();
  return nullptr;
}
} // namespace

void do_initialize(MessageHandler *m, InitializeParam &param,
                   ReplyOnce &reply) {
  std::string project_path = normalizePath(param.rootUri->getPath());
  LOG_S(INFO) << "initialize in directory " << project_path << " with uri "
              << param.rootUri->raw_uri;

  {
    g_config = new Config(param.initializationOptions);
    rapidjson::Document reader;
    for (const std::string &str : g_init_options) {
      reader.Parse(str.c_str());
      if (!reader.HasParseError()) {
        JsonReader json_reader{&reader};
        try {
          reflect(json_reader, *g_config);
        } catch (std::invalid_argument &) {
          // This will not trigger because parse error is handled in
          // MessageRegistry::Parse in lsp.cc
        }
      }
    }

    rapidjson::StringBuffer output;
    rapidjson::Writer<rapidjson::StringBuffer> writer(output);
    JsonWriter json_writer(&writer);
    reflect(json_writer, *g_config);
    LOG_S(INFO) << "initializationOptions: " << output.GetString();

    if (g_config->cache.directory.size()) {
      SmallString<256> path(g_config->cache.directory);
      sys::fs::make_absolute(project_path, path);
      // Use upper case for the Driver letter on Windows.
      g_config->cache.directory = normalizePath(path.str());
      ensureEndsInSlash(g_config->cache.directory);
    }
  }

  // Client capabilities
  const auto &capabilities = param.capabilities;
  g_config->client.hierarchicalDocumentSymbolSupport &=
      capabilities.textDocument.documentSymbol
          .hierarchicalDocumentSymbolSupport;
  g_config->client.linkSupport &=
      capabilities.textDocument.definition.linkSupport;
  g_config->client.snippetSupport &=
      capabilities.textDocument.completion.completionItem.snippetSupport;
  g_config->client.diagnosticsRelatedInformation &=
      capabilities.textDocument.publishDiagnostics.relatedInformation;
  didChangeWatchedFiles =
      capabilities.workspace.didChangeWatchedFiles.dynamicRegistration;

  if (!g_config->client.snippetSupport)
    g_config->completion.duplicateOptional = false;

  // Ensure there is a resource directory.
  if (g_config->clang.resourceDir.empty())
    g_config->clang.resourceDir = getDefaultResourceDirectory();
  doPathMapping(g_config->clang.resourceDir);
  LOG_S(INFO) << "use -resource-dir=" << g_config->clang.resourceDir;

  // Send initialization before starting indexers, so we don't send a
  // status update too early.
  {
    InitializeResult result;
    auto &c = result.capabilities;
    c.documentOnTypeFormattingProvider =
        g_config->capabilities.documentOnTypeFormattingProvider;
    c.foldingRangeProvider = g_config->capabilities.foldingRangeProvider;
    c.workspace = g_config->capabilities.workspace;
    reply(result);
  }

  // Set project root.
  ensureEndsInSlash(project_path);
  g_config->fallbackFolder = project_path;
  auto &workspaceFolders = g_config->workspaceFolders;
  for (const WorkspaceFolder &wf : param.workspaceFolders) {
    std::string path = wf.uri.getPath();
    ensureEndsInSlash(path);
    std::string real = realPath(path) + '/';
    workspaceFolders.emplace_back(path, real);
  }
  if (workspaceFolders.empty()) {
    std::string real = realPath(project_path) + '/';
    workspaceFolders.emplace_back(project_path, real);
  }
  std::sort(workspaceFolders.begin(), workspaceFolders.end(),
            [](auto &l, auto &r) { return l.first.size() > r.first.size(); });
  for (auto &[folder, real] : workspaceFolders)
    if (real == folder)
      LOG_S(INFO) << "workspace folder: " << folder;
    else
      LOG_S(INFO) << "workspace folder: " << folder << " -> " << real;

  if (g_config->cache.directory.empty())
    g_config->cache.retainInMemory = 1;
  else if (!g_config->cache.hierarchicalPath)
    for (auto &[folder, _] : workspaceFolders) {
      // Create two cache directories for files inside and outside of the
      // project.
      std::string escaped = escapeFileName(folder.substr(0, folder.size() - 1));
      sys::fs::create_directories(g_config->cache.directory + escaped);
      sys::fs::create_directories(g_config->cache.directory + '@' + escaped);
    }

  idx::init();
  for (auto &[folder, _] : workspaceFolders)
    m->project->load(folder);

  // Start indexer threads. Start this after loading the project, as that
  // may take a long time. Indexer threads will emit status/progress
  // reports.
  if (g_config->index.threads == 0)
    g_config->index.threads = (int)std::thread::hardware_concurrency();

  LOG_S(INFO) << "start " << g_config->index.threads << " indexers";
  for (int i = 0; i < g_config->index.threads; i++)
    spawnThread(indexer, new std::pair<MessageHandler *, int>{m, i});

  // Start scanning include directories before dispatching project
  // files, because that takes a long time.
  m->include_complete->rescan();

  LOG_S(INFO) << "dispatch initial index requests";
  m->project->index(m->wfiles, reply.id);

  m->manager->sessions.setCapacity(g_config->session.maxNum);
}

void MessageHandler::initialize(JsonReader &reader, ReplyOnce &reply) {
  InitializeParam param;
  reflect(reader, param);
  auto it = reader.m->FindMember("initializationOptions");
  if (it != reader.m->MemberEnd() && it->value.IsObject()) {
    JsonReader m1(&it->value);
    try {
      reflect(m1, param.initializationOptions);
    } catch (std::invalid_argument &) {
      reader.path_.push_back("initializationOptions");
      reader.path_.insert(reader.path_.end(), m1.path_.begin(), m1.path_.end());
      throw;
    }
  }
  if (!param.rootUri) {
    reply.error(ErrorCode::InvalidRequest, "expected rootUri");
    return;
  }
  do_initialize(this, param, reply);
}

void standaloneInitialize(MessageHandler &handler, const std::string &root) {
  InitializeParam param;
  param.rootUri = DocumentUri::fromPath(root);
  ReplyOnce reply{handler};
  do_initialize(&handler, param, reply);
}

void MessageHandler::initialized(EmptyParam &) {
  if (didChangeWatchedFiles) {
    RegistrationParam param;
    pipeline::request("client/registerCapability", param);
  }
}

void MessageHandler::shutdown(EmptyParam &, ReplyOnce &reply) {
  reply(JsonNull{});
}

void MessageHandler::exit(EmptyParam &) {
  pipeline::g_quit.store(true, std::memory_order_relaxed);
}
} // namespace ccls