//
// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2021
//
// Distributed under the Boost Software License, Version 1.0. (See accompanying
// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
#include "td/tl/tl_config.h"

#include <cassert>
#include <cstdio>
#include <cstdlib>

namespace td {
namespace tl {

const std::int32_t TLS_SCHEMA_V2 = 0x3a2f9be2;
const std::int32_t TLS_SCHEMA_V3 = 0xe4a8604b;
const std::int32_t TLS_SCHEMA_V4 = 0x90ac88d7;
const std::int32_t TLS_TYPE = 0x12eb4386;
const std::int32_t TLS_COMBINATOR = 0x5c0a1ed5;
const std::int32_t TLS_COMBINATOR_LEFT_BUILTIN = 0xcd211f63;
const std::int32_t TLS_COMBINATOR_LEFT = 0x4c12c6d9;
const std::int32_t TLS_COMBINATOR_RIGHT_V2 = 0x2c064372;
const std::int32_t TLS_ARG_V2 = 0x29dfe61b;

const std::int32_t TLS_EXPR_NAT = 0xdcb49bd8;
const std::int32_t TLS_EXPR_TYPE = 0xecc9da78;

const std::int32_t TLS_NAT_CONST_OLD = 0xdcb49bd8;
const std::int32_t TLS_NAT_CONST = 0x8ce940b1;
const std::int32_t TLS_NAT_VAR = 0x4e8a14f0;
const std::int32_t TLS_TYPE_VAR = 0x0142ceae;
const std::int32_t TLS_ARRAY = 0xd9fb20de;
const std::int32_t TLS_TYPE_EXPR = 0xc1863d08;

void tl_config::add_type(tl_type *type) {
  types.push_back(type);
  id_to_type[type->id] = type;
  name_to_type[type->name] = type;
}

tl_type *tl_config::get_type(std::int32_t type_id) const {
  std::map<std::int32_t, tl_type *>::const_iterator it = id_to_type.find(type_id);
  assert(it != id_to_type.end());
  return it->second;
}

tl_type *tl_config::get_type(const std::string &type_name) {
  return name_to_type[type_name];
}

void tl_config::add_function(tl_combinator *function) {
  functions.push_back(function);
  id_to_function[function->id] = function;
  name_to_function[function->name] = function;
}

tl_combinator *tl_config::get_function(std::int32_t function_id) {
  return id_to_function[function_id];
}

tl_combinator *tl_config::get_function(const std::string &function_name) {
  return name_to_function[function_name];
}

std::size_t tl_config::get_type_count() const {
  return types.size();
}

tl_type *tl_config::get_type_by_num(std::size_t num) const {
  return types[num];
}

std::size_t tl_config::get_function_count() const {
  return functions.size();
}

tl_combinator *tl_config::get_function_by_num(std::size_t num) const {
  return functions[num];
}

std::int32_t tl_config_parser::try_parse_int() {
  return try_parse(p.fetch_int());
}

std::int64_t tl_config_parser::try_parse_long() {
  return try_parse(p.fetch_long());
}

std::string tl_config_parser::try_parse_string() {
  return try_parse(p.fetch_string());
}

template <class T>
T tl_config_parser::try_parse(const T &res) const {
  if (p.get_error() != NULL) {
    std::fprintf(stderr, "Wrong TL-scheme specified: %s at %d\n", p.get_error(), static_cast<int>(p.get_error_pos()));
    std::abort();
  }

  return res;
}

int tl_config_parser::get_schema_version(std::int32_t version_id) {
  if (version_id == TLS_SCHEMA_V4) {
    return 4;
  }
  if (version_id == TLS_SCHEMA_V3) {
    return 3;
  }
  if (version_id == TLS_SCHEMA_V2) {
    return 2;
  }
  return -1;
}

tl_tree *tl_config_parser::read_num_const() {
  int num = static_cast<int>(try_parse_int());

  return new tl_tree_nat_const(FLAG_NOVAR, num);
}

tl_tree *tl_config_parser::read_num_var(int *var_count) {
  std::int32_t diff = try_parse_int();
  int var_num = static_cast<int>(try_parse_int());

  if (var_num >= *var_count) {
    *var_count = var_num + 1;
  }

  return new tl_tree_var_num(0, var_num, diff);
}

tl_tree *tl_config_parser::read_type_var(int *var_count) {
  int var_num = static_cast<int>(try_parse_int());
  std::int32_t flags = try_parse_int();

  if (var_num >= *var_count) {
    *var_count = var_num + 1;
  }
  assert(!(flags & (FLAG_NOVAR | FLAG_BARE)));

  return new tl_tree_var_type(flags, var_num);
}

tl_tree *tl_config_parser::read_array(int *var_count) {
  std::int32_t flags = FLAG_NOVAR;
  tl_tree *multiplicity = read_nat_expr(var_count);

  tl_tree_array *T = new tl_tree_array(flags, multiplicity, read_args_list(var_count));

  for (std::size_t i = 0; i < T->args.size(); i++) {
    if (!(T->args[i].flags & FLAG_NOVAR)) {
      T->flags &= ~FLAG_NOVAR;
    }
  }
  return T;
}

tl_tree *tl_config_parser::read_type(int *var_count) {
  tl_type *type = config.get_type(try_parse_int());
  assert(type != NULL);
  std::int32_t flags = try_parse_int() | FLAG_NOVAR;
  int arity = static_cast<int>(try_parse_int());
  assert(type->arity == arity);

  tl_tree_type *T = new tl_tree_type(flags, type, arity);
  for (std::int32_t i = 0; i < arity; i++) {
    tl_tree *child = read_expr(var_count);

    T->children[i] = child;
    if (!(child->flags & FLAG_NOVAR)) {
      T->flags &= ~FLAG_NOVAR;
    }
  }
  return T;
}

tl_tree *tl_config_parser::read_type_expr(int *var_count) {
  std::int32_t tree_type = try_parse_int();
  switch (tree_type) {
    case TLS_TYPE_VAR:
      return read_type_var(var_count);
    case TLS_TYPE_EXPR:
      return read_type(var_count);
    case TLS_ARRAY:
      return read_array(var_count);
    default:
      std::fprintf(stderr, "tree_type = %d\n", static_cast<int>(tree_type));
      std::abort();
  }
}

tl_tree *tl_config_parser::read_nat_expr(int *var_count) {
  std::int32_t tree_type = try_parse_int();
  switch (tree_type) {
    case TLS_NAT_CONST_OLD:
    case TLS_NAT_CONST:
      return read_num_const();
    case TLS_NAT_VAR:
      return read_num_var(var_count);
    default:
      std::fprintf(stderr, "tree_type = %d\n", static_cast<int>(tree_type));
      std::abort();
  }
}

tl_tree *tl_config_parser::read_expr(int *var_count) {
  std::int32_t tree_type = try_parse_int();
  switch (tree_type) {
    case TLS_EXPR_NAT:
      return read_nat_expr(var_count);
    case TLS_EXPR_TYPE:
      return read_type_expr(var_count);
    default:
      std::fprintf(stderr, "tree_type = %d\n", static_cast<int>(tree_type));
      std::abort();
  }
}

std::vector<arg> tl_config_parser::read_args_list(int *var_count) {
  const int schema_flag_opt_field = 2 << static_cast<int>(schema_version >= 3);
  const int schema_flag_has_vars = schema_flag_opt_field ^ 6;

  std::size_t args_num = static_cast<size_t>(try_parse_int());
  std::vector<arg> args(args_num);
  for (std::size_t i = 0; i < args_num; i++) {
    arg cur_arg;

    std::int32_t arg_v = try_parse_int();
    if (arg_v != TLS_ARG_V2) {
      std::fprintf(stderr, "Wrong tls_arg magic %d\n", static_cast<int>(arg_v));
      std::abort();
    }

    cur_arg.name = try_parse_string();
    cur_arg.flags = try_parse_int();

    bool is_optional = false;
    if (cur_arg.flags & schema_flag_opt_field) {
      cur_arg.flags &= ~schema_flag_opt_field;
      is_optional = true;
    }
    if (cur_arg.flags & schema_flag_has_vars) {
      cur_arg.flags &= ~schema_flag_has_vars;
      cur_arg.var_num = static_cast<int>(try_parse_int());
    } else {
      cur_arg.var_num = -1;
    }

    if (cur_arg.var_num >= *var_count) {
      *var_count = cur_arg.var_num + 1;
    }
    if (is_optional) {
      cur_arg.exist_var_num = static_cast<int>(try_parse_int());
      cur_arg.exist_var_bit = static_cast<int>(try_parse_int());
    } else {
      cur_arg.exist_var_num = -1;
      cur_arg.exist_var_bit = 0;
    }
    cur_arg.type = read_type_expr(var_count);
    if (/*cur_arg.var_num < 0 && cur_arg.exist_var_num < 0 && */ (cur_arg.type->flags & FLAG_NOVAR)) {
      cur_arg.flags |= FLAG_NOVAR;
    }

    args[i] = cur_arg;
  }
  return args;
}

tl_combinator *tl_config_parser::read_combinator() {
  std::int32_t t = try_parse_int();
  if (t != TLS_COMBINATOR) {
    std::fprintf(stderr, "Wrong tls_combinator magic %d\n", static_cast<int>(t));
    std::abort();
  }

  tl_combinator *combinator = new tl_combinator();
  combinator->id = try_parse_int();
  combinator->name = try_parse_string();
  combinator->type_id = try_parse_int();
  combinator->var_count = 0;

  std::int32_t left_type = try_parse_int();
  if (left_type == TLS_COMBINATOR_LEFT) {
    combinator->args = read_args_list(&combinator->var_count);
  } else {
    if (left_type != TLS_COMBINATOR_LEFT_BUILTIN) {
      std::fprintf(stderr, "Wrong tls_combinator_left magic %d\n", static_cast<int>(left_type));
      std::abort();
    }
  }

  std::int32_t right_ver = try_parse_int();
  if (right_ver != TLS_COMBINATOR_RIGHT_V2) {
    std::fprintf(stderr, "Wrong tls_combinator_right magic %d\n", static_cast<int>(right_ver));
    std::abort();
  }
  combinator->result = read_type_expr(&combinator->var_count);

  return combinator;
}

tl_type *tl_config_parser::read_type() {
  std::int32_t t = try_parse_int();
  if (t != TLS_TYPE) {
    std::fprintf(stderr, "Wrong tls_type magic %d\n", t);
    std::abort();
  }

  tl_type *type = new tl_type();
  type->id = try_parse_int();
  type->name = try_parse_string();
  type->constructors_num = static_cast<std::size_t>(try_parse_int());
  type->constructors.reserve(type->constructors_num);
  type->flags = try_parse_int();
  type->flags &= ~(1 | 8 | 16 | 1024);
  if (type->flags != 0) {
    std::fprintf(stderr, "Type %s has non-zero flags: %d\n", type->name.c_str(), static_cast<int>(type->flags));
  }
  type->arity = static_cast<int>(try_parse_int());

  try_parse_long();  // unused
  return type;
}

tl_config tl_config_parser::parse_config() {
  schema_version = get_schema_version(try_parse_int());
  if (schema_version < 2) {
    std::fprintf(stderr, "Unsupported tl-schema version %d\n", static_cast<int>(schema_version));
    std::abort();
  }

  try_parse_int();  // date
  try_parse_int();  // version

  std::int32_t types_n = try_parse_int();
  std::size_t constructors_total = 0;
  for (std::int32_t i = 0; i < types_n; i++) {
    tl_type *type = read_type();
    config.add_type(type);
    constructors_total += type->constructors_num;
  }

  std::int32_t constructors_n = try_parse_int();
  assert(static_cast<std::size_t>(constructors_n) == constructors_total);
  for (std::int32_t i = 0; i < constructors_n; i++) {
    tl_combinator *constructor = read_combinator();
    config.get_type(constructor->type_id)->add_constructor(constructor);
  }

  std::int32_t functions_n = try_parse_int();
  for (std::int32_t i = 0; i < functions_n; i++) {
    config.add_function(read_combinator());
  }
  p.fetch_end();
  try_parse(0);

  return config;
}

}  // namespace tl
}  // namespace td