#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/cervus.h>

static int failed = 0;
static void ok(const char *s)   { printf("  [OK]  %s\n", s); }
static void fail(const char *s) { printf("  [FAIL] %s\n", s); failed = 1; }

int main(int argc, char **argv)
{
    (void)argc; (void)argv;
    puts("--- test_pipe ---");

    int fds[2] = { -1, -1 };
    if (pipe(fds) == 0 && fds[0] >= 0 && fds[1] >= 0) ok("pipe() creates two fds");
    else { fail("pipe() failed"); return 1; }
    printf("  read_fd=%d write_fd=%d\n", fds[0], fds[1]);

    {
        const char *msg = "hello pipe";
        ssize_t w = write(fds[1], msg, strlen(msg));
        if (w == (ssize_t)strlen(msg)) ok("write to pipe");
        else fail("write to pipe");

        char buf[32];
        memset(buf, 0, sizeof(buf));
        ssize_t r = read(fds[0], buf, sizeof(buf) - 1);
        if (r == (ssize_t)strlen(msg) && strcmp(buf, msg) == 0)
            ok("read from pipe matches written data");
        else fail("read from pipe");
    }
    close(fds[0]); close(fds[1]);

    {
        int p[2];
        if (pipe(p) != 0) { fail("pipe for fork test"); return 1; }
        pid_t child = fork();
        if (child < 0) { fail("fork"); return 1; }
        if (child == 0) {
            close(p[0]);
            const char *s = "world";
            write(p[1], s, strlen(s));
            close(p[1]);
            return 0;
        }
        close(p[1]);
        char buf[32]; memset(buf, 0, sizeof(buf));
        ssize_t r = read(p[0], buf, sizeof(buf) - 1);
        close(p[0]);
        int status = 0; waitpid(child, &status, 0);
        if (r > 0 && strcmp(buf, "world") == 0) ok("pipe IPC parent<-child");
        else fail("pipe IPC");
    }

    {
        int p[2];
        if (pipe(p) != 0) { fail("pipe for dup2 test"); return 1; }
        pid_t child = fork();
        if (child < 0) { fail("fork for dup2"); return 1; }
        if (child == 0) {
            close(p[0]);
            dup2(p[1], 1);
            close(p[1]);
            const char *s = "from child stdout\n";
            write(1, s, strlen(s));
            return 0;
        }
        close(p[1]);
        char buf[64]; memset(buf, 0, sizeof(buf));
        ssize_t r = read(p[0], buf, sizeof(buf) - 1);
        close(p[0]);
        int status = 0; waitpid(child, &status, 0);
        if (r > 0 && strncmp(buf, "from child stdout", 17) == 0)
            ok("dup2 redirects child stdout through pipe");
        else fail("dup2 redirect");
    }

    puts("--- test_pipe done ---");
    return failed ? 1 : 0;
}