#pragma once

#include "lsp_diagnostic.h"
#include "utils.h"

#include <clang-c/Index.h>
#include <optional>

#include <mutex>
#include <string>

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<lsDiagnostic> 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);

  // TODO: Move FindClosestCallNameInBuffer and FindStableCompletionSource into
  // lex_utils.h/cc

  // Finds the closest 'callable' name prior to position. This is used for
  // signature help to filter code completion results.
  //
  // |completion_position| will be point to a good code completion location to
  // for fetching signatures.
  std::string FindClosestCallNameInBuffer(
      lsPosition position,
      int* active_parameter,
      lsPosition* completion_position = nullptr) const;

  // 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.
  lsPosition FindStableCompletionSource(lsPosition position,
                                        bool* is_global_completion,
                                        std::string* existing_completion,
                                        lsPosition* 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);

  // Run |action| under the lock.
  void DoAction(const std::function<void()>& action);
  // Run |action| on the file identified by |filename|. This executes under the
  // lock.
  void DoActionOnFile(const std::string& filename,
                      const std::function<void(WorkingFile* file)>& action);

  WorkingFile* OnOpen(const lsTextDocumentItem& open);
  void OnChange(const lsTextDocumentDidChangeParams& change);
  void OnClose(const lsTextDocumentIdentifier& close);

  // If |filter_paths| is non-empty, only files which contain any of the given
  // strings. For example, {"foo", "bar"} means that every result has either the
  // string "foo" or "bar" contained within it.
  Snapshot AsSnapshot(const std::vector<std::string>& filter_paths);

  // 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(lsPosition position, std::string_view content);

std::string_view LexIdentifierAroundPos(lsPosition position,
                                        std::string_view content);