/* Undo snapshots, persistent permission rules and session store helpers. */
#define _POSIX_C_SOURCE 200809L

#include "cst_agent.h"
#include "cst_perms.h"
#include "cst_undo.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.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 char g_ws[256];

static void wfile(const char *rel, const char *s) {
  char p[512];
  snprintf(p, sizeof(p), "%s/%s", g_ws, rel);
  FILE *fp = fopen(p, "wb");
  if (fp) {
    fputs(s, fp);
    fclose(fp);
  }
}

static int rfile_eq(const char *rel, const char *want) {
  char p[512], buf[256] = {0};
  snprintf(p, sizeof(p), "%s/%s", g_ws, rel);
  FILE *fp = fopen(p, "rb");
  if (!fp)
    return want == NULL;
  size_t n = fread(buf, 1, sizeof(buf) - 1, fp);
  fclose(fp);
  buf[n] = 0;
  return want && strcmp(buf, want) == 0;
}

static void test_undo(void) {
  const char *sid = "s1";
  wfile("a.txt", "v1\n");
  EXPECT(cst_undo_count(g_ws, sid) == 0, "no undo yet");

  /* turn 1: edit a.txt twice, create new.txt */
  EXPECT(cst_undo_snapshot(g_ws, sid, "t1", "a.txt") == 0, "snap a");
  wfile("a.txt", "v2\n");
  EXPECT(cst_undo_snapshot(g_ws, sid, "t1", "a.txt") == 0, "snap a again");
  wfile("a.txt", "v3\n");
  EXPECT(cst_undo_snapshot(g_ws, sid, "t1", "new.txt") == 0, "snap absent");
  wfile("new.txt", "hello\n");
  EXPECT(cst_undo_count(g_ws, sid) == 1, "one turn");

  /* turn 2: edit a.txt again */
  EXPECT(cst_undo_snapshot(g_ws, sid, "t2", "a.txt") == 0, "snap t2");
  wfile("a.txt", "v4\n");
  EXPECT(cst_undo_count(g_ws, sid) == 2, "two turns");

  char rep[1024];
  EXPECT(cst_undo_restore_last(g_ws, sid, rep, sizeof(rep)) == 0, "undo t2");
  EXPECT(rfile_eq("a.txt", "v3\n"), "a back to v3");
  EXPECT(rfile_eq("new.txt", "hello\n"), "new.txt kept by t2 undo");
  EXPECT(strstr(rep, "a.txt") != NULL, "report names a.txt");

  EXPECT(cst_undo_restore_last(g_ws, sid, rep, sizeof(rep)) == 0, "undo t1");
  EXPECT(rfile_eq("a.txt", "v1\n"), "a back to v1 (first snapshot wins)");
  EXPECT(rfile_eq("new.txt", NULL), "new.txt removed");
  EXPECT(cst_undo_count(g_ws, sid) == 0, "nothing left");
  EXPECT(cst_undo_restore_last(g_ws, sid, rep, sizeof(rep)) != 0,
         "undo with nothing fails");

  /* subdirectory file that did not exist, parent dirs created later */
  EXPECT(cst_undo_snapshot(g_ws, sid, "t3", "d/e/f.txt") == 0, "snap nested");
  char p[512];
  snprintf(p, sizeof(p), "%s/d", g_ws);
  mkdir(p, 0755);
  snprintf(p, sizeof(p), "%s/d/e", g_ws);
  mkdir(p, 0755);
  wfile("d/e/f.txt", "x");
  EXPECT(cst_undo_restore_last(g_ws, sid, rep, sizeof(rep)) == 0, "undo t3");
  EXPECT(rfile_eq("d/e/f.txt", NULL), "nested file removed");

  /* escaping paths are refused */
  EXPECT(cst_undo_snapshot(g_ws, sid, "t4", "../evil") != 0, "reject ..");
  EXPECT(cst_undo_snapshot(g_ws, sid, "t4", "/etc/passwd") != 0,
         "reject absolute");
}

static void test_perms(void) {
  cst_perms_t *p = cst_perms_open(g_ws);
  EXPECT(p != NULL, "open perms");
  EXPECT(!cst_perms_tool_allowed(p, "write_file"), "empty rules");
  EXPECT(cst_perms_allow_tool(p, "write_file") == 0, "allow tool");
  EXPECT(cst_perms_allow_prefix(p, "git status") == 0, "allow prefix");
  cst_perms_close(p);

  p = cst_perms_open(g_ws);
  EXPECT(cst_perms_tool_allowed(p, "write_file"), "tool rule persisted");
  EXPECT(!cst_perms_tool_allowed(p, "delete_file"), "other tool not allowed");
  EXPECT(cst_perms_shell_allowed(p, "git status"), "exact prefix");
  EXPECT(cst_perms_shell_allowed(p, "git status -s"), "prefix + args");
  EXPECT(!cst_perms_shell_allowed(p, "git statusx"), "word boundary");
  EXPECT(!cst_perms_shell_allowed(p, "git status; rm -rf ~"), "meta ;");
  EXPECT(!cst_perms_shell_allowed(p, "git status && make"), "meta &&");
  EXPECT(!cst_perms_shell_allowed(p, "git status $(id)"), "meta $(");
  EXPECT(!cst_perms_shell_allowed(p, "git status > x"), "meta >");
  EXPECT(!cst_perms_shell_allowed(p, "git status\nrm x"), "newline");
  char *d = cst_perms_describe(p);
  EXPECT(d && strstr(d, "git status") && strstr(d, "write_file"), "describe");
  free(d);
  EXPECT(cst_perms_reset(p) == 0, "reset");
  EXPECT(!cst_perms_tool_allowed(p, "write_file"), "reset clears tools");
  EXPECT(!cst_perms_shell_allowed(p, "git status"), "reset clears prefixes");
  cst_perms_close(p);

  char out[128];
  cst_perms_suggest_prefix("git commit -m 'x'", out, sizeof(out));
  EXPECT(strcmp(out, "git commit") == 0, "git two words");
  cst_perms_suggest_prefix("  ls -la src", out, sizeof(out));
  EXPECT(strcmp(out, "ls") == 0, "ls one word");
  cst_perms_suggest_prefix("make -j8", out, sizeof(out));
  EXPECT(strcmp(out, "make") == 0, "make");
  cst_perms_suggest_prefix("rm -rf build", out, sizeof(out));
  EXPECT(out[0] == 0, "no rule for rm");
  cst_perms_suggest_prefix("sudo make install", out, sizeof(out));
  EXPECT(out[0] == 0, "no rule for sudo");
  cst_perms_suggest_prefix("python3 -c 'print(1)'", out, sizeof(out));
  EXPECT(out[0] == 0, "no rule for python3 -c");
  cst_perms_suggest_prefix("python3 -m pytest", out, sizeof(out));
  EXPECT(out[0] == 0, "no rule for python3 -m");
  cst_perms_suggest_prefix("npm test", out, sizeof(out));
  EXPECT(strcmp(out, "npm test") == 0, "npm test");
}

static void test_store(void) {
  EXPECT(cst_agent_store_ensure(g_ws) == 0, "store ensure");
  char path[1024];
  EXPECT(cst_agent_store_path_for_id(g_ws, "20260101-000000-abcd", path,
                                     sizeof(path)) == 0,
         "path for id");
  FILE *fp = fopen(path, "w");
  EXPECT(fp != NULL, "create session file");
  if (fp) {
    fputs("{\"role\":\"system\",\"content\":\"sys\"}\n", fp);
    fputs("{\"role\":\"user\",\"content\":\"fix the\\nbuild\"}\n", fp);
    fputs("{\"role\":\"assistant\",\"content\":\"ok\"}\n", fp);
    fclose(fp);
  }
  cst_agent_store_set_current(g_ws, "20260101-000000-abcd");
  cst_session_info_t in;
  EXPECT(cst_agent_store_info(g_ws, "20260101-000000-abcd", &in) == 0, "info");
  EXPECT(in.messages == 3, "message count");
  EXPECT(strcmp(in.first_user, "fix the build") == 0, "first user line");
  EXPECT(in.title[0] == 0, "no title yet");
  EXPECT(cst_agent_store_title_set(g_ws, "20260101-000000-abcd", "Build fix") ==
             0,
         "set title");
  cst_agent_store_info(g_ws, "20260101-000000-abcd", &in);
  EXPECT(strcmp(in.title, "Build fix") == 0, "title read back");
  EXPECT(cst_agent_store_title_set(g_ws, "../x", "bad") != 0, "bad id");
  EXPECT(cst_agent_store_delete(g_ws, "20260101-000000-abcd") == 0, "delete");
  EXPECT(access(path, F_OK) != 0, "session file gone");
  char cur[128];
  EXPECT(cst_agent_store_get_current(g_ws, cur, sizeof(cur)) != 0,
         "CURRENT cleared");
}

int main(void) {
  snprintf(g_ws, sizeof(g_ws), "/tmp/cst_test_undo_XXXXXX");
  if (!mkdtemp(g_ws)) {
    perror("mkdtemp");
    return 1;
  }
  test_undo();
  test_perms();
  test_store();
  char cmd[512];
  snprintf(cmd, sizeof(cmd), "rm -rf '%s'", g_ws);
  if (system(cmd) != 0)
    fprintf(stderr, "warning: cleanup failed\n");
  if (nfail) {
    fprintf(stderr, "test_undo: %d failure(s)\n", nfail);
    return 1;
  }
  printf("test_undo: ok\n");
  return 0;
}