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

#pragma once

#include "lsp.hh"
#include "utils.hh"

#include <mutex>
#include <optional>
#include <string>

namespace ccls {
struct WorkingFile {
  int version = 0;
  std::string filename;

  std::string buffer_content;
  // Note: This assumes 0-based lines (1-based lines are normally assumed).
  std::vector<std::string> index_lines;
  // Note: This assumes 0-based lines (1-based lines are normally assumed).
  std::vector<std::string> buffer_lines;
  // Mappings between index line number and buffer line number.
  // Empty indicates either buffer or index has been changed and re-computation
  // is required.
  // For index_to_buffer[i] == j, if j >= 0, we are confident that index line
  // i maps to buffer line j; if j == -1, FindMatchingLine will use the nearest
  // confident lines to resolve its line number.
  std::vector<int> index_to_buffer;
  std::vector<int> buffer_to_index;
  // A set of diagnostics that have been reported for this file.
  // NOTE: _ is appended because it must be accessed under the WorkingFiles
  // lock!
  std::vector<Diagnostic> diagnostics_;

  WorkingFile(const std::string &filename, const std::string &buffer_content);

  // This should be called when the indexed content has changed.
  void SetIndexContent(const std::string &index_content);
  // This should be called whenever |buffer_content| has changed.
  void OnBufferContentUpdated();

  // Finds the buffer line number which maps to index line number |line|.
  // Also resolves |column| if not NULL.
  // When resolving a range, use is_end = false for begin() and is_end =
  // true for end() to get a better alignment of |column|.
  std::optional<int> GetBufferPosFromIndexPos(int line, int *column,
                                              bool is_end);
  // Finds the index line number which maps to buffer line number |line|.
  // Also resolves |column| if not NULL.
  std::optional<int> GetIndexPosFromBufferPos(int line, int *column,
                                              bool is_end);
  // Returns a relatively stable completion position (it jumps back until there
  // is a non-alphanumeric character).
  //
  // The out param |is_global_completion| is set to true if this looks like a
  // global completion.
  // The out param |existing_completion| is set to any existing completion
  // content the user has entered.
  Position FindStableCompletionSource(Position position,
                                        std::string *existing_completion,
                                        Position *replace_end_pos) const;

private:
  // Compute index_to_buffer and buffer_to_index.
  void ComputeLineMapping();
};

struct WorkingFiles {
  struct Snapshot {
    struct File {
      std::string filename;
      std::string content;
    };

    std::vector<File> files;
  };

  //
  // :: IMPORTANT :: All methods in this class are guarded by a single lock.
  //

  // Find the file with the given filename.
  WorkingFile *GetFileByFilename(const std::string &filename);
  WorkingFile *GetFileByFilenameNoLock(const std::string &filename);
  std::string GetContent(const std::string &filename);

  // Run |action| under the lock.
  template <typename Fn> void DoAction(Fn &&fn) {
    std::lock_guard<std::mutex> lock(files_mutex);
    fn();
  }

  WorkingFile *OnOpen(const TextDocumentItem &open);
  void OnChange(const TextDocumentDidChangeParam &change);
  void OnClose(const TextDocumentIdentifier &close);

  // Use unique_ptrs so we can handout WorkingFile ptrs and not have them
  // invalidated if we resize files.
  std::vector<std::unique_ptr<WorkingFile>> files;
  std::mutex files_mutex; // Protects |files|.
};

int GetOffsetForPosition(Position pos, std::string_view content);

std::string_view LexIdentifierAroundPos(Position position,
                                        std::string_view content);
} // namespace ccls