#include "map_header_bridge.h"
#include "factorio_map_header.h"
#include <string.h>

struct w2c_map__host {
  w2c_factorio__map__header *module;
  unsigned reads;
};

u32 w2c_map__host_read_or_throw(struct w2c_map__host *env, u64 source, u64 destination, u64 size) {
  wasm_rt_memory_t *memory = w2c_factorio__map__header_memory(env->module);
  if (memory->size < 24 || source > memory->size - 24 ||
      size > memory->size || destination > memory->size - size) return 2;
  uint64_t reader[3];
  memcpy(reader, memory->data + source, sizeof(reader));
  uint64_t data = reader[0], length = reader[1], cursor = reader[2];
  if (data > memory->size || length > memory->size - data) return 2;
  if (cursor > length || size > length - cursor) return 1;
  memmove(memory->data + destination, memory->data + data + cursor, (size_t)size);
  cursor += size;
  memcpy(memory->data + source + 16, &cursor, sizeof(cursor));
  ++env->reads;
  return 0;
}

int factorio_map_header_parse(const uint8_t *payload, size_t length,
                             FactorioMapVersion version, FactorioMapHeader *out) {
  if (!payload || !out) return 2;
  if (!wasm_rt_is_initialized()) wasm_rt_init();
  w2c_factorio__map__header module;
  struct w2c_map__host env = {.module = &module};
  wasm2c_factorio__map__header_instantiate(&module, &env);
  uint8_t *memory = w2c_factorio__map__header_memory(&module)->data;
  uint64_t registers[32] = {0};
  registers[0] = 2048; registers[1] = 512; registers[31] = 65280;
  uint64_t reader[5] = {4096, length < 24 ? length : 24, 0,
    (uint64_t)version.major << 48 | (uint64_t)version.minor << 32 |
    (uint64_t)version.patch << 16 | version.build, version.flag};
  memcpy(memory, registers, sizeof(registers));
  memcpy(memory + 512, reader, sizeof(reader));
  memcpy(memory + 4096, payload, (size_t)reader[1]);
  int result = (int)w2c_factorio__map__header_run(&module, 0, 1000);
  if (!result) {
    FactorioMapHeader parsed = {.version = version};
    memcpy(parsed.tick_fields, memory + 2064, sizeof(parsed.tick_fields));
    *out = parsed;
  }
  wasm2c_factorio__map__header_free(&module);
  return result;
}