// client.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <semaphore.h>
#include <unistd.h>

#define SHM_BUFFER_SIZE 1024

typedef struct {
    int has_data;
    int result_code;
    char buffer[SHM_BUFFER_SIZE];
} shared_block_t;

int main(int argc, char *argv[]) {
    if (argc < 4) {
        fprintf(stderr,
                "Usage: %s <shm_name> <sem_client_name> <sem_server_name>\n",
                argv[0]);
        return -1;
    }

    const char *shm_name = argv[1];
    const char *sem_client_name = argv[2];
    const char *sem_server_name = argv[3];

    int shm_fd = shm_open(shm_name, O_RDWR, 0);
    if (shm_fd == -1) {
        perror("shm_open");
        return -1;
    }

    shared_block_t *shm_ptr = mmap(NULL,
                                   sizeof(shared_block_t),
                                   PROT_READ | PROT_WRITE,
                                   MAP_SHARED,
                                   shm_fd,
                                   0);
    if (shm_ptr == MAP_FAILED) {
        perror("mmap");
        close(shm_fd);
        return -1;
    }

    if (close(shm_fd) == -1) {
        perror("close");
    }

    sem_t *sem_client = sem_open(sem_client_name, 0);
    if (sem_client == SEM_FAILED) {
        perror("sem_open(sem_client)");
        munmap(shm_ptr, sizeof(shared_block_t));
        return -1;
    }

    sem_t *sem_server = sem_open(sem_server_name, 0);
    if (sem_server == SEM_FAILED) {
        perror("sem_open(sem_server)");
        sem_close(sem_client);
        munmap(shm_ptr, sizeof(shared_block_t));
        return -1;
    }

    FILE *fin = fopen("input.txt", "r");
    if (!fin) {
        perror("fopen(input.txt)");
        sem_close(sem_client);
        sem_close(sem_server);
        munmap(shm_ptr, sizeof(shared_block_t));
        return -1;
    }

    char input[SHM_BUFFER_SIZE];

    while (fgets(input, sizeof(input), fin) != NULL) {
        size_t len = strlen(input);
        if (len > 0 && input[len - 1] == '\n') {
            input[len - 1] = '\0';
        }

        memset(shm_ptr->buffer, 0, sizeof(shm_ptr->buffer));
        strncpy(shm_ptr->buffer, input, SHM_BUFFER_SIZE - 1);
        shm_ptr->buffer[SHM_BUFFER_SIZE - 1] = '\0';

        shm_ptr->has_data = 1;

        if (sem_post(sem_client) == -1) {
            perror("sem_post(sem_client)");
            fclose(fin);
            sem_close(sem_client);
            sem_close(sem_server);
            munmap(shm_ptr, sizeof(shared_block_t));
            return -1;
        }

        if (sem_wait(sem_server) == -1) {
            perror("sem_wait(sem_server)");
            fclose(fin);
            sem_close(sem_client);
            sem_close(sem_server);
            munmap(shm_ptr, sizeof(shared_block_t));
            return -1;
        }

        if (shm_ptr->result_code != 0) {
            fprintf(stderr,
                    "Server reported error, result_code = %d\n",
                    shm_ptr->result_code);
            fclose(fin);
            sem_close(sem_client);
            sem_close(sem_server);
            munmap(shm_ptr, sizeof(shared_block_t));
            return -1;
        }

        printf("%s\n", shm_ptr->buffer);
    }

    if (fclose(fin) == EOF) {
        perror("fclose(input.txt)");
    }

    if (sem_close(sem_client) == -1) {
        perror("sem_close(sem_client)");
    }
    if (sem_close(sem_server) == -1) {
        perror("sem_close(sem_server)");
    }

    if (munmap(shm_ptr, sizeof(shared_block_t)) == -1) {
        perror("munmap");
    }

    return 0;
}