#ifndef _DEFAULT_SOURCE
#define _DEFAULT_SOURCE
#endif
#ifndef _XOPEN_SOURCE
#define _XOPEN_SOURCE 700
#endif

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

#include "cJSON.h"
#include "cst_agent.h"
#include "cst_sandbox.h"
#include "cst_tools.h"
#include "cst_util.h"
#include "cst_version.h"
#include "os_compat.h"
#include "tools_internal.h"

#ifndef _WIN32
#include <sys/utsname.h>
#include <unistd.h>
#else
#include <windows.h>
#endif

/* A search that does not care about case: the model asks "where did we talk
 * about the store", and nobody remembers how it was capitalised. */
static const char *find_in(const char *hay, const char *needle, int icase) {
  size_t nn = strlen(needle);
  if (!nn)
    return NULL;
  for (const char *p = hay; *p; p++) {
    if (!icase) {
      if (strncmp(p, needle, nn) == 0)
        return p;
      continue;
    }
    size_t i = 0;
    while (i < nn && p[i] &&
           tolower((unsigned char)p[i]) == tolower((unsigned char)needle[i]))
      i++;
    if (i == nn)
      return p;
  }
  return NULL;
}

/* A line of context around a match: control characters become spaces (one
 * transcript line is one JSON object anyway) and the tail is marked. */
static void say_context(cst_buf_t *b, const char *from, size_t max) {
  size_t i = 0;
  while (from[i] && i < max) {
    char c = from[i];
    if (c == '\n' || c == '\r' || c == '\t')
      c = ' ';
    cst_buf_append(b, &c, 1);
    i++;
  }
  if (from[i])
    cst_buf_puts(b, " ...");
}

/* --- session_search ------------------------------------------------------ */

/* What was said before: every stored session's transcript, line by line. The
 * store is the same one the CLI, the TUI, the WebUI and the app use, so this
 * is how "we solved this last week" is answered without a shell. */
int cst_tool_session_search(const cst_tool_ctx_t *ctx, const ctl_tool_call_t *c,
                            cst_tool_result_t *r) {
  const char *query = tool_arg(c, "query");
  if (!query || !query[0])
    return tool_set_result(r, "error: missing query", 1);
  while (*query == ' ')
    query++;
  if (!query[0])
    return tool_set_result(r, "error: missing query", 1);
  long want = tool_arg_long(c, "max_matches", 20);
  if (want <= 0)
    want = 20;
  if (want > 100)
    want = 100;
  int icase = tool_arg_bool(c, "ignore_case", 1);
  /* A store grows without bound and this walks all of it, so it gets a
   * budget: the walk stops when it is spent and says so, instead of making a
   * turn sit for minutes on a workspace with a few hundred sessions. */
  long budget_bytes = tool_arg_long(c, "max_bytes", 32L << 20);
  if (budget_bytes <= 0)
    budget_bytes = 32L << 20;
  long budget_ms = tool_arg_long(c, "max_seconds", 5);
  if (budget_ms <= 0)
    budget_ms = 5;
  budget_ms *= 1000;
  const double t_start = os_now_ms();
  long scanned_bytes = 0;
  int cut = 0; /* the budget stopped the walk */

  static char ids[200][128];
  int n = cst_agent_store_list(ctx->workspace_root, ids, 200);
  cst_buf_t hits = {0};
  int matches = 0, in_sessions = 0, scanned_sessions = 0;
  for (int i = 0; i < n && matches < (int)want; i++) {
    if (scanned_bytes >= budget_bytes ||
        os_now_ms() - t_start > (double)budget_ms) {
      cut = 1;
      break;
    }
    char path[OS_PATH_MAX];
    if (cst_agent_store_path_for_id(ctx->workspace_root, ids[i], path,
                                    sizeof(path)) != 0)
      continue;
    FILE *fp = fopen(path, "rb");
    if (!fp)
      continue;
    scanned_sessions++;
    cst_session_info_t in;
    int have_info = cst_agent_store_info(ctx->workspace_root, ids[i], &in) == 0;
    int in_this = 0, lineno = 0;
    char *line = NULL;
    size_t cap = 0;
    cst_buf_t one = {0};
    ssize_t got;
    while ((got = getline(&line, &cap, fp)) > 0) {
      lineno++;
      scanned_bytes += got;
      /* A tool output line can be megabytes (a whole file read back): such a
       * line is not scanned -- one cJSON tree per block of it would be the
       * slowest thing in the turn. */
      if (got <= 1 || got > (1 << 16)) {
        if (scanned_bytes >= budget_bytes) {
          cut = 1;
          break;
        }
        continue;
      }
      /* the clock is asked every so often: a clock_gettime per line would be
       * the next slowest thing after the parse */
      if ((lineno & 0xFF) == 0 && ((scanned_bytes >= budget_bytes ||
                                    os_now_ms() - t_start > (double)budget_ms))) {
        cut = 1;
        break;
      }
      cJSON *o = cJSON_Parse(line);
      if (!o)
        continue;
      const cJSON *role = cJSON_GetObjectItemCaseSensitive(o, "role");
      const cJSON *content = cJSON_GetObjectItemCaseSensitive(o, "content");
      const char *txt = cJSON_IsString(content) ? content->valuestring : NULL;
      const char *at = txt ? find_in(txt, query, icase) : NULL;
      int stop = 0;
      if (at) {
        if (!in_this) {
          in_this = 1;
          in_sessions++;
          cst_buf_printf(&one, "\n%s", ids[i]);
          if (have_info && in.messages)
            cst_buf_printf(&one, " · %d msgs", in.messages);
          if (have_info && in.title[0])
            cst_buf_printf(&one, " · %s", in.title);
          else if (have_info && in.first_user[0])
            cst_buf_printf(&one, " · %s", in.first_user);
          cst_buf_puts(&one, "\n");
        }
        const char *who = cJSON_IsString(role) ? role->valuestring : "?";
        const char *meta = NULL;
        const cJSON *kind =
            cJSON_GetObjectItemCaseSensitive(
                cJSON_GetObjectItemCaseSensitive(o, "meta"), "kind");
        if (cJSON_IsString(kind))
          meta = kind->valuestring;
        /* a little before the match, a line's worth after it */
        const char *start = at;
        for (int back = 0; start > txt && back < 60; back++)
          start--;
        cst_buf_printf(&one, "  #%d %s%s: ", lineno, who,
                       meta && strcmp(meta, "note") == 0 ? " (note)" : "");
        say_context(&one, start, (size_t)(at - start) + strlen(query) + 160);
        cst_buf_puts(&one, "\n");
        matches++;
        stop = matches >= (int)want;
      }
      cJSON_Delete(o);
      if (stop)
        break;
    }
    cst_buf_append(&hits, one.buf, one.buf ? one.len : 0);
    cst_buf_free(&one);
    free(line);
    fclose(fp);
  }
  if (matches == 0) {
    cst_buf_free(&hits);
    return tool_set_resultf(r, 0,
                            "no match for \"%.80s\" in %d of %d stored session%s"
                            " (%.1f MB scanned%s)\n",
                            query, scanned_sessions, n,
                            scanned_sessions == 1 ? "" : "s",
                            (double)scanned_bytes / (1024.0 * 1024.0),
                            cut ? "; the budget stopped the walk -- raise "
                                  "max_bytes or max_seconds"
                                : "");
  }
  cst_buf_t out = {0};
  cst_buf_printf(&out, "%d match%s for \"%.80s\" in %d of %d stored session%s\n",
                 matches, matches == 1 ? "" : "es", query, in_sessions,
                 scanned_sessions, scanned_sessions == 1 ? "" : "s");
  cst_buf_append(&out, hits.buf, hits.len);
  if (matches >= (int)want)
    cst_buf_puts(&out, "\n(more may match; raise max_matches or narrow the "
                       "query)\n");
  if (cut)
    cst_buf_printf(&out,
                   "\n(the walk stopped after %.1f MB / %.1f s of a %d MB store: "
                   "older sessions were not looked at -- raise max_bytes or "
                   "max_seconds to go further)\n",
                   (double)scanned_bytes / (1024.0 * 1024.0),
                   (os_now_ms() - t_start) / 1000.0, n);
  cst_buf_free(&hits);
  return tool_take_buf(r, &out, 0);
}

/* --- device_info --------------------------------------------------------- */

/* Where this agent is running: enough for the model to stop guessing (a
 * phone in a pocket and a desktop in a terminal answer differently), and no
 * more than that -- no serial numbers, no accounts. */
int cst_tool_device_info(const cst_tool_ctx_t *ctx, const ctl_tool_call_t *c,
                         cst_tool_result_t *r) {
  (void)c;
  cst_buf_t b = {0};
  cst_buf_printf(&b, "cst-agent %s\n", CST_VERSION);
#if defined(__ANDROID__)
  const char *plat = "android";
#elif defined(_WIN32)
  const char *plat = "windows";
#elif defined(__APPLE__)
  const char *plat = "macos";
#elif defined(__linux__)
  const char *plat = "linux";
#else
  const char *plat = "unknown";
#endif
#ifdef _WIN32
  char host[160] = "";
  os_windows_version(host, sizeof(host));
  SYSTEM_INFO si;
  memset(&si, 0, sizeof(si));
  GetSystemInfo(&si);
  cst_buf_printf(&b, "system: %s (%d-bit, %lu CPUs)\n",
                 host[0] ? host : plat, (int)(sizeof(void *) * 8),
                 (unsigned long)si.dwNumberOfProcessors);
#else
  struct utsname u;
  long cpus = sysconf(_SC_NPROCESSORS_ONLN);
  if (uname(&u) == 0)
    cst_buf_printf(&b, "system: %s %.80s %.60s (%d-bit, %ld CPUs)\n",
                   u.sysname, u.release, u.machine, (int)(sizeof(void *) * 8),
                   cpus > 0 ? cpus : 0L);
  else
    cst_buf_printf(&b, "system: %s (%d-bit)\n", plat,
                   (int)(sizeof(void *) * 8));
#endif
  cst_buf_printf(&b, "workspace: %s\n",
                 ctx->workspace_root ? ctx->workspace_root : "?");
  cst_buf_printf(&b, "sandbox: %s\n", cst_sandbox_name(cst_sandbox_probe()));
  const cst_agent_config_t *cfg = ctx->agent ? cst_agent_config(ctx->agent) : NULL;
  if (cfg) {
    char sid[128] = "";
    cst_agent_session_id(ctx->agent, sid, sizeof(sid));
    cst_buf_printf(&b, "session: %.120s\n", sid[0] ? sid : "(none)");
    cst_buf_printf(&b, "model: %.60s · %.30s · effort %.12s · mode %.12s\n",
                   cfg->model, cfg->provider, cfg->effort, cfg->mode);
    cst_buf_printf(&b, "permissions: approval %s%s%s\n",
                   cst_approval_name(cfg->approval),
                   cfg->plan_mode ? ", plan mode (read-only)" : "",
                   cfg->auto_approve ? ", unattended" : "");
    cst_buf_printf(&b, "steps: %d model calls per turn max\n", cfg->max_steps);
  }
  char dir[OS_PATH_MAX];
  if (os_config_dir(dir, sizeof(dir)) == 0)
    cst_buf_printf(&b, "config: %s\n", dir);
  if (os_temp_dir(dir, sizeof(dir)) == 0)
    cst_buf_printf(&b, "temp: %s\n", dir);
  if (os_exe_dir(dir, sizeof(dir)) == 0)
    cst_buf_printf(&b, "program: %s\n", dir);
  cst_buf_printf(&b, "process: pid %d\n", (int)os_getpid());
  return tool_take_buf(r, &b, 0);
}