/* am.c — MeowOS 活动管理器用户侧 CLI（AMSD_DESIGN.md §3，安卓习惯，进固件 /usr/bin/am）。
 *
 * 连 amsd sock（--sock/MEOW_AMS_SOCK，默认 /usr/data/meow_ams.sock），发一条命令行，
 * 读响应直到 EOF，格式化输出。root 免鉴权（读）；写操作（start/kill）一期仅 root/系统身份。
 *
 * 子命令：
 *   am status                 → 在跑 App 表（pkg/状态/pid/运行时长/activity）
 *   am list                   → 注册表 + 状态（pkg/name/state/pid/launches/crashes）
 *   am history [pkg]          → 事件历史（每 App 最近 8 条；无 pkg=全部）
 *   am start <pkg>[/<activity>] → 经 amsd→launcher 拉起
 *   am kill  <pkg>            → 经 amsd→launcher 终止（SIGTERM 语义）
 *
 * 编译（mipsel 静态）：zig-mipsel-cc -Os -Wall -Wextra -static am.c -o am
 * 宿主：gcc -Os -Wall -Wextra am.c -o am_host
 */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/socket.h>
#include <sys/un.h>

#define AMS_SOCK_DEFAULT "/usr/data/meow_ams.sock"
#define AMS_SOCK_PATH_MAX 108
#define AMS_RESP_MAX 65536

static const char *g_sock = NULL;

static int connect_path(const char *path)
{
    int fd = socket(AF_UNIX, SOCK_STREAM, 0);
    if (fd < 0) { perror("socket"); return -1; }
    struct sockaddr_un a;
    memset(&a, 0, sizeof a);
    a.sun_family = AF_UNIX;
    snprintf(a.sun_path, sizeof a.sun_path, "%s", path);
    if (connect(fd, (struct sockaddr *)&a, sizeof a) < 0) {
        fprintf(stderr, "connect %s: %s\n", path, strerror(errno));
        close(fd);
        return -1;
    }
    return fd;
}

/* 发送单行命令，读取响应直到 EOF，打印。返回 0=ok。 */
static int am_query(const char *cmd)
{
    int fd = connect_path(g_sock);
    if (fd < 0) return 1;
    ssize_t w = write(fd, cmd, strlen(cmd));
    (void)w;
    static char resp[AMS_RESP_MAX];
    size_t n = 0;
    char tmp[2048];
    ssize_t r;
    while ((r = read(fd, tmp, sizeof tmp)) > 0) {
        if (n + (size_t)r < sizeof resp - 1) { memcpy(resp + n, tmp, (size_t)r); n += (size_t)r; }
    }
    close(fd);
    resp[n] = '\0';
    fputs(resp, stdout);
    return 0;
}

static int cmd_status(void)
{
    return am_query("status\n");
}

static int cmd_list(void)
{
    return am_query("list\n");
}

static int cmd_history(const char *pkg)
{
    char line[512];
    if (pkg && pkg[0])
        snprintf(line, sizeof line, "history %s\n", pkg);
    else
        snprintf(line, sizeof line, "history\n");
    return am_query(line);
}

static int cmd_start(const char *spec)
{
    if (geteuid() != 0) { printf("ERR permission denied (root only)\n"); return 1; }
    char line[512];
    snprintf(line, sizeof line, "start %s\n", spec);
    return am_query(line);
}

static int cmd_kill(const char *pkg)
{
    if (geteuid() != 0) { printf("ERR permission denied (root only)\n"); return 1; }
    char line[512];
    snprintf(line, sizeof line, "kill %s\n", pkg);
    return am_query(line);
}

static void usage(const char *a0)
{
    fprintf(stderr,
        "usage: %s [--sock <path>] status|list|history [pkg]|start <pkg>[/<act>]|kill <pkg>\n"
        "  --sock <path>   amsd socket (default %s, or $MEOW_AMS_SOCK)\n",
        a0, AMS_SOCK_DEFAULT);
}

int main(int argc, char **argv)
{
    const char *env = getenv("MEOW_AMS_SOCK");
    g_sock = (env && env[0]) ? env : AMS_SOCK_DEFAULT;

    const char *cmd = NULL, *arg = NULL;
    for (int i = 1; i < argc; i++) {
        const char *a = argv[i];
        if (!strcmp(a, "--sock") && i + 1 < argc) g_sock = argv[++i];
        else if (!strcmp(a, "-h") || !strcmp(a, "--help")) { usage(argv[0]); return 0; }
        else if (a[0] == '-') { usage(argv[0]); return 2; }
        else if (!cmd) cmd = a;
        else if (!arg) arg = a;
        else { fprintf(stderr, "extra arg %s\n", a); return 2; }
    }
    if (!cmd) { usage(argv[0]); return 2; }

    if (!strcmp(cmd, "status")) return cmd_status();
    if (!strcmp(cmd, "list")) return cmd_list();
    if (!strcmp(cmd, "history")) return cmd_history(arg);
    if (!strcmp(cmd, "start")) {
        if (!arg) { fprintf(stderr, "start needs <pkg>[/<act>]\n"); return 2; }
        return cmd_start(arg);
    }
    if (!strcmp(cmd, "kill")) {
        if (!arg) { fprintf(stderr, "kill needs <pkg>\n"); return 2; }
        return cmd_kill(arg);
    }
    usage(argv[0]);
    return 2;
}