#include "tree_sitter/runtime.h"
#include "tree_sitter/parser.h"
#include "runtime/tree.h"
#include "runtime/node.h"
#include <string.h>

struct TSDocument {
  TSParser *parser;
  const TSTree *tree;
  TSInput input;
  size_t error_count;
};

TSDocument * ts_document_make() {
  TSDocument *document = malloc(sizeof(TSDocument));
  *document = (TSDocument) {
    .input = (TSInput) {}
  };
  return document;
}

void ts_document_free(TSDocument *document) {
  if (document->parser)
    ts_parser_free(document->parser);
  if (document->input.release_fn)
    document->input.release_fn(document->input.data);
  free(document);
}

void ts_document_set_parser(TSDocument *document, TSParser *parser) {
  if (document->parser)
    ts_parser_free(document->parser);
  document->parser = parser;
}

const TSTree * ts_document_tree(const TSDocument *document) {
  return document->tree;
}

const char * ts_document_string(const TSDocument *document) {
  return ts_tree_string(document->tree, ts_parser_config(document->parser).symbol_names);
}

void ts_document_set_input(TSDocument *document, TSInput input) {
  document->input = input;
  document->tree = ts_parser_parse(document->parser, document->input, NULL);
}

void ts_document_edit(TSDocument *document, TSInputEdit edit) {
  document->tree = ts_parser_parse(document->parser, document->input, &edit);
}

const char * ts_document_symbol_name(const TSDocument *document, const TSTree *tree) {
  return ts_parser_config(document->parser).symbol_names[tree->symbol];
}

typedef struct {
  const char *string;
  size_t position;
  size_t length;
} TSStringInput;

const char * ts_string_input_read(void *d, size_t *bytes_read) {
  TSStringInput *data = (TSStringInput *)d;
  if (data->position >= data->length) {
    *bytes_read = 0;
    return "";
  }
  size_t previous_position = data->position;
  data->position = data->length;
  *bytes_read = data->position - previous_position;
  return data->string + previous_position;
}

int ts_string_input_seek(void *d, size_t position) {
  TSStringInput *data = (TSStringInput *)d;
  data->position = position;
  return (position < data->length);
}

TSInput ts_string_input_make(const char *string) {
  TSStringInput *data = malloc(sizeof(TSStringInput));
  data->string = string;
  data->position = 0;
  data->length = strlen(string);
  TSInput input = {
    .data = (void *)data,
    .read_fn = ts_string_input_read,
    .seek_fn = ts_string_input_seek,
    .release_fn = free,
  };
  return input;
}

void ts_document_set_input_string(TSDocument *document, const char *text) {
  ts_document_set_input(document, ts_string_input_make(text));
}

TSNode * ts_document_root_node(const TSDocument *document) {
  return ts_node_make_root(document->tree, document->parser->config.symbol_names);
}

TSNode * ts_document_get_node(const TSDocument *document, size_t pos) {
  TSNode *root = ts_document_root_node(document);
  TSNode *result = ts_node_leaf_at_pos(root, pos);
  ts_node_release(root);
  return result;
}