#define _POSIX_C_SOURCE 200809L

#include "cJSON.h"
#include "cst_agent.h"

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

static int nfail;

#define EXPECT(cond, msg)                                                      \
  do {                                                                         \
    if (!(cond)) {                                                             \
      fprintf(stderr, "FAIL %s:%d: %s\n", __FILE__, __LINE__, msg);            \
      nfail++;                                                                 \
    }                                                                          \
  } while (0)

static const char *TRICKY = "tab\there \"q\" back\\slash\nnew line \x01 中文";
static const char *TC = "[{\"id\":\"c1\",\"type\":\"function\",\"function\":{"
                        "\"name\":\"read_file\",\"arguments\":"
                        "\"{\\\"path\\\":\\\"a.c\\\"}\"}}]";

/* compare JSON texts structurally */
static int json_eq(const char *a, const char *b) {
  cJSON *ja = cJSON_Parse(a), *jb = cJSON_Parse(b);
  int eq = ja && jb && cJSON_Compare(ja, jb, 1);
  cJSON_Delete(ja);
  cJSON_Delete(jb);
  return eq;
}

static void append(cst_session_t *s, cst_role_t role, const char *content,
                   const char *tid, const char *tname, const char *tc,
                   const char *meta) {
  cst_message_t m;
  memset(&m, 0, sizeof(m));
  m.role = role;
  m.content = (char *)content;
  if (tid)
    snprintf(m.tool_call_id, sizeof(m.tool_call_id), "%s", tid);
  if (tname)
    snprintf(m.tool_name, sizeof(m.tool_name), "%s", tname);
  m.tool_calls_json = (char *)tc;
  m.meta_json = (char *)meta;
  EXPECT(cst_session_append(s, &m) == 0, "append");
}

static void check_messages(cst_session_t *s) {
  EXPECT(cst_session_count(s) == 5, "5 messages");
  const cst_message_t *m = cst_session_get(s, 0);
  EXPECT(m && m->role == CST_ROLE_SYSTEM, "system role");
  m = cst_session_get(s, 1);
  EXPECT(m && m->role == CST_ROLE_USER && strcmp(m->content, TRICKY) == 0,
         "tricky user text exact");
  m = cst_session_get(s, 2);
  EXPECT(m && m->role == CST_ROLE_ASSISTANT, "assistant role");
  EXPECT(m && m->tool_calls_json && json_eq(m->tool_calls_json, TC),
         "tool_calls preserved");
  EXPECT(m && m->meta_json && json_eq(m->meta_json, "{\"protocol\":\"native-eos\"}"),
         "assistant meta");
  m = cst_session_get(s, 3);
  EXPECT(m && m->role == CST_ROLE_TOOL && strcmp(m->tool_call_id, "c1") == 0 &&
             strcmp(m->tool_name, "read_file") == 0,
         "tool id/name");
  EXPECT(m && strcmp(m->content, "int a;\n\tx\n") == 0, "tool content");
  m = cst_session_get(s, 4);
  EXPECT(m && m->role == CST_ROLE_USER && strcmp(m->tool_call_id, "c2") == 0,
         "text-protocol result frame keeps tool_call_id");
  EXPECT(m && m->meta_json &&
             json_eq(m->meta_json,
                     "{\"kind\":\"tool_result\",\"protocol\":\"ctl\"}"),
         "result frame meta");
}

int main(void) {
  char path[256];
  snprintf(path, sizeof(path), "/tmp/cst-session-test-%d.jsonl", (int)getpid());
  remove(path);

  cst_session_t *s = cst_session_open(path);
  EXPECT(s != NULL, "open new");
  if (!s)
    return 1;
  append(s, CST_ROLE_SYSTEM, "sys", NULL, NULL, NULL, NULL);
  append(s, CST_ROLE_USER, TRICKY, NULL, NULL, NULL, NULL);
  append(s, CST_ROLE_ASSISTANT, "", NULL, NULL, TC,
         "{\"protocol\":\"native-eos\"}");
  append(s, CST_ROLE_TOOL, "int a;\n\tx\n", "c1", "read_file", NULL, NULL);
  append(s, CST_ROLE_USER, "result c2 exit=0 2\nok\nend", "c2", "run_shell",
         NULL, "{\"kind\":\"tool_result\",\"protocol\":\"ctl\"}");
  check_messages(s);
  cst_session_close(s);

  /* reload from disk */
  s = cst_session_open(path);
  EXPECT(s != NULL, "reopen");
  if (!s)
    return 1;
  check_messages(s);

  /* every line on disk is standalone valid JSON with tool_calls as array */
  FILE *fp = fopen(path, "r");
  char line[8192];
  int lines = 0, arrays = 0;
  while (fp && fgets(line, sizeof(line), fp)) {
    cJSON *j = cJSON_Parse(line);
    EXPECT(j != NULL, "jsonl line parses");
    if (cJSON_IsArray(cJSON_GetObjectItemCaseSensitive(j, "tool_calls")))
      arrays++;
    cJSON_Delete(j);
    lines++;
  }
  if (fp)
    fclose(fp);
  EXPECT(lines == 5 && arrays == 1, "5 lines, tool_calls stored as array");

  /* rewrite + clear(keep_system) */
  const cst_message_t *first = cst_session_get(s, 0);
  cst_message_t keep[2];
  keep[0] = *first;
  keep[1] = *cst_session_get(s, 1);
  EXPECT(cst_session_rewrite(s, keep, 2) == 0, "rewrite");
  EXPECT(cst_session_count(s) == 2, "rewrite count");
  EXPECT(cst_session_clear(s, 1) == 0 && cst_session_count(s) == 1,
         "clear keeps system");
  cst_session_close(s);

  /* legacy format: tool_calls_json stored as a string */
  fp = fopen(path, "w");
  fprintf(fp, "{\"role\":\"assistant\",\"content\":\"\",\"tool_calls_json\":"
              "\"[{\\\"id\\\":\\\"c9\\\",\\\"type\\\":\\\"function\\\","
              "\\\"function\\\":{\\\"name\\\":\\\"run_shell\\\","
              "\\\"arguments\\\":\\\"{}\\\"}}]\"}\n");
  fprintf(fp, "not json at all\n");
  fprintf(fp, "{\"role\":\"tool\",\"content\":\"out\",\"tool_call_id\":\"c9\"}\n");
  fclose(fp);
  s = cst_session_open(path);
  EXPECT(s != NULL, "open legacy");
  if (s) {
    EXPECT(cst_session_count(s) == 2, "legacy: bad line skipped");
    const cst_message_t *m = cst_session_get(s, 0);
    EXPECT(m && m->tool_calls_json && strstr(m->tool_calls_json, "c9"),
           "legacy tool_calls_json read");
    cst_session_close(s);
  }
  remove(path);

  if (nfail) {
    fprintf(stderr, "test_session_roundtrip: %d failed\n", nfail);
    return 1;
  }
  printf("test_session_roundtrip: OK\n");
  return 0;
}