#include "dowa/dowa.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static const char *Get_String(Dowa_JSON_Entry *object, const char *key)
{
  char *value = Dowa_JSON_Get_String(object, key);
  return value ? value : "";
}

/* Validates the optional "history" array from a turn.start command.
 * Returns TRUE if history is absent, null, or structurally valid (<=20
 * entries, each an object with role user/assistant and string content).
 * Returns FALSE and sets *error_out on any violation. */
static boolean Validate_History(
    Dowa_JSON_Entry *object,
    Dowa_Arena *p_arena,
    const char **error_out)
{
  (void)p_arena;
  *error_out = NULL;
  Dowa_JSON_Value *hist_val = Dowa_JSON_Get(object, "history");
  if (!hist_val || hist_val->type == DOWA_JSON_NULL)
    return TRUE;
  if (hist_val->type != DOWA_JSON_ARRAY)
  {
    *error_out = "history must be a list";
    return FALSE;
  }
  size_t count = Dowa_Array_Length(hist_val->array_val);
  if (count > 20)
  {
    *error_out = "history must not exceed 20 entries";
    return FALSE;
  }
  for (size_t i = 0; i < count; i++)
  {
    Dowa_JSON_Value *v = &hist_val->array_val[i];
    if (v->type != DOWA_JSON_OBJECT)
    {
      *error_out = "each history entry must be an object";
      return FALSE;
    }
    Dowa_JSON_Entry *entry = v->object_val;
    Dowa_JSON_Value *role_val    = Dowa_JSON_Get(entry, "role");
    Dowa_JSON_Value *content_val = Dowa_JSON_Get(entry, "content");
    if (!role_val || role_val->type != DOWA_JSON_STRING)
    {
      *error_out = "history role must be a string";
      return FALSE;
    }
    if (!content_val || content_val->type != DOWA_JSON_STRING)
    {
      *error_out = "history content must be a string";
      return FALSE;
    }
    const char *role = role_val->str_val;
    if (!role ||
        (strcmp(role, "user") != 0 && strcmp(role, "assistant") != 0))
    {
      *error_out = "history role must be user or assistant";
      return FALSE;
    }
  }
  return TRUE;
}

int main(void)
{
  printf(
      "{\"type\":\"ready\",\"request_id\":null,"
      "\"conversation_id\":null,\"status\":\"ok\"}\n");
  fflush(stdout);

  char *line = NULL;
  size_t capacity = 0;
  while (getline(&line, &capacity, stdin) >= 0)
  {
    Dowa_Arena *p_arena = Dowa_Arena_Create(64 * 1024);
    Dowa_JSON_Value parsed = Dowa_JSON_Parse(
        line, (int32)strlen(line), p_arena);
    if (parsed.type != DOWA_JSON_OBJECT)
    {
      Dowa_Arena_Free(p_arena);
      continue;
    }
    Dowa_JSON_Entry *object = parsed.object_val;
    const char *command = Get_String(object, "command");
    const char *request_id = Get_String(object, "request_id");
    const char *conversation_id = Get_String(object, "conversation_id");
    if (strcmp(command, "shutdown") == 0)
    {
      printf(
          "{\"type\":\"turn.done\",\"request_id\":\"%s\","
          "\"conversation_id\":\"\"}\n",
          request_id);
      fflush(stdout);
      Dowa_Arena_Free(p_arena);
      break;
    }
    if (strcmp(command, "turn.start") == 0)
    {
      /* Validate history before any other processing. */
      const char *hist_error = NULL;
      if (!Validate_History(object, p_arena, &hist_error))
      {
        printf(
            "{\"type\":\"turn.error\",\"request_id\":\"%s\","
            "\"conversation_id\":\"%s\","
            "\"error\":{\"code\":\"invalid_history\","
            "\"message\":\"%s\"}}\n",
            request_id,
            conversation_id,
            hist_error);
        printf(
            "{\"type\":\"turn.done\",\"request_id\":\"%s\","
            "\"conversation_id\":\"%s\",\"failed\":true}\n",
            request_id,
            conversation_id);
        fflush(stdout);
        Dowa_Arena_Free(p_arena);
        continue;
      }

      const char *prompt_profile = Get_String(object, "prompt_profile");
      double prompt_version = Dowa_JSON_Get_Number(object, "prompt_version");
      double knowledge_version =
          Dowa_JSON_Get_Number(object, "knowledge_version");
      boolean known_profile =
          strcmp(prompt_profile, "public_visitor") == 0 ||
          strcmp(prompt_profile, "invited_friend") == 0 ||
          strcmp(prompt_profile, "june_admin") == 0;
      if (!known_profile || prompt_version != 1 || knowledge_version != 1)
      {
        printf(
            "{\"type\":\"turn.error\",\"request_id\":\"%s\","
            "\"conversation_id\":\"%s\","
            "\"error\":{\"code\":\"invalid_prompt_profile\","
            "\"message\":\"prompt profile is required\"}}\n",
            request_id,
            conversation_id);
        printf(
            "{\"type\":\"turn.done\",\"request_id\":\"%s\","
            "\"conversation_id\":\"%s\",\"failed\":true}\n",
            request_id,
            conversation_id);
        fflush(stdout);
        Dowa_Arena_Free(p_arena);
        continue;
      }
      printf(
          "{\"type\":\"turn.accepted\",\"request_id\":\"%s\","
          "\"conversation_id\":\"%s\"}\n",
          request_id,
          conversation_id);
      printf(
          "{\"type\":\"tool.started\",\"request_id\":\"%s\","
          "\"conversation_id\":\"%s\","
          "\"tool\":{\"name\":\"mock-search\","
          "\"prompt_profile\":\"%s\"}}\n",
          request_id,
          conversation_id,
          prompt_profile);
      printf(
          "{\"type\":\"assistant.delta\",\"request_id\":\"%s\","
          "\"conversation_id\":\"%s\","
          "\"delta\":\"hello \\\"traveler\\\"\\\\path\"}\n",
          request_id,
          conversation_id);
      printf(
          "{\"type\":\"assistant.completed\",\"request_id\":\"%s\","
          "\"conversation_id\":\"%s\","
          "\"content\":\"hello traveler\"}\n",
          request_id,
          conversation_id);
      printf(
          "{\"type\":\"assistant.usage\",\"request_id\":\"%s\","
          "\"conversation_id\":\"%s\","
          "\"usage\":{\"input_tokens\":7,\"output_tokens\":3}}\n",
          request_id,
          conversation_id);
      printf(
          "{\"type\":\"turn.done\",\"request_id\":\"%s\","
          "\"conversation_id\":\"%s\"}\n",
          request_id,
          conversation_id);
      fflush(stdout);
    }
    Dowa_Arena_Free(p_arena);
  }
  free(line);
  return 0;
}