#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <math.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <arpa/inet.h>
#include "types.h"
#include "native_functions.h"
#include "interpreter.h"

void register_native_func(char *name, NativeFunc func) {
    if (!name || !func || native_func_cnt >= 100) {
        return;
    }
    NativeFuncDef *nf = &native_funcs[native_func_cnt++];
    strncpy(nf->name, name, 31);
    nf->name[31] = 0;
    nf->func = func;
}

long native_socket(long *args, int argc) {
    if (!args || argc < 3) {
        return -1;
    }
    int domain = (int)args[0];
    int type = (int)args[1];
    int protocol = (int)args[2];
    return socket(domain, type, protocol);
}

long native_bind(long *args, int argc) {
    if (!args || argc < 2) {
        return -1;
    }
    int sockfd = (int)args[0];
    int port = (int)args[1];

    struct sockaddr_in addr;
    memset(&addr, 0, sizeof(addr));
    addr.sin_family = AF_INET;
    addr.sin_addr.s_addr = INADDR_ANY;
    addr.sin_port = htons(port);

    return bind(sockfd, (struct sockaddr*)&addr, sizeof(addr));
}

long native_listen(long *args, int argc) {
    if (!args || argc < 2) {
        return -1;
    }
    int sockfd = (int)args[0];
    int backlog = (int)args[1];
    return listen(sockfd, backlog);
}

long native_accept(long *args, int argc) {
    if (!args || argc < 1) {
        return -1;
    }
    int sockfd = (int)args[0];
    return accept(sockfd, NULL, NULL);
}

long native_recv(long *args, int argc) {
    if (!args || argc < 4) {
        return -1;
    }
    int sockfd = (int)args[0];
    int addr = (int)args[1];
    int len = (int)args[2];
    int flags = (int)args[3];

    if (addr < 0 || addr >= MEM_SIZE) {
        return -1;
    }

    char temp_buf[8192];
    if (len > 8192) len = 8192;
    if (len < 0) len = 0;

    if (addr + len > MEM_SIZE) {
        len = MEM_SIZE - addr;
    }

    int result = recv(sockfd, temp_buf, len, flags);
    if (result > 0) {
        for (int i = 0; i < result && addr + i < MEM_SIZE; i++) {
            memory[addr + i] = temp_buf[i];
        }
    }
    return result;
}

long native_send(long *args, int argc) {
    if (!args || argc < 4) {
        return -1;
    }
    int sockfd = (int)args[0];
    long buf_arg = args[1];
    int len = (int)args[2];
    int flags = (int)args[3];

    if (len < 0) {
        return -1;
    }

    if (buf_arg > MEM_SIZE * 8 || buf_arg < 0) {
        return send(sockfd, (char*)buf_arg, len, flags);
    }

    if (buf_arg >= MEM_SIZE) {
        return -1;
    }

    char temp_buf[8192];
    if (len > 8192) len = 8192;

    if (buf_arg + len > MEM_SIZE) {
        len = MEM_SIZE - buf_arg;
    }

    for (int i = 0; i < len && buf_arg + i < MEM_SIZE; i++) {
        temp_buf[i] = (char)memory[buf_arg + i];
    }

    return send(sockfd, temp_buf, len, flags);
}

long native_close(long *args, int argc) {
    if (!args || argc < 1) {
        return -1;
    }
    int fd = (int)args[0];
    return close(fd);
}

long native_strlen(long *args, int argc) {
    if (!args || argc < 1) {
        return 0;
    }
    char *str = (char*)args[0];
    if (!str) {
        return 0;
    }
    return strlen(str);
}

long native_AF_INET(long *args, int argc) {
    return AF_INET;
}

long native_SOCK_STREAM(long *args, int argc) {
    return SOCK_STREAM;
}

long native_sqrt(long *args, int argc) {
    if (!args || argc < 1) {
        return 0;
    }
    return (long)sqrt((double)args[0]);
}

long native_pow(long *args, int argc) {
    if (!args || argc < 2) {
        return 0;
    }
    return (long)pow((double)args[0], (double)args[1]);
}

long native_sin(long *args, int argc) {
    if (!args || argc < 1) {
        return 0;
    }
    return (long)(sin((double)args[0]) * 1000000);
}

long native_cos(long *args, int argc) {
    if (!args || argc < 1) {
        return 0;
    }
    return (long)(cos((double)args[0]) * 1000000);
}

long native_tan(long *args, int argc) {
    if (!args || argc < 1) {
        return 0;
    }
    return (long)(tan((double)args[0]) * 1000000);
}

long native_abs(long *args, int argc) {
    if (!args || argc < 1) {
        return 0;
    }
    return (long)abs((int)args[0]);
}

long native_floor(long *args, int argc) {
    if (!args || argc < 1) {
        return 0;
    }
    return (long)floor((double)args[0]);
}

long native_ceil(long *args, int argc) {
    if (!args || argc < 1) {
        return 0;
    }
    return (long)ceil((double)args[0]);
}

long native_strpos(long *args, int argc) {
    if (!args || argc < 2) {
        return -1;
    }
    char *haystack = (char*)args[0];
    char *needle = (char*)args[1];
    if (!haystack || !needle) {
        return -1;
    }
    char *pos = strstr(haystack, needle);
    if (pos) {
        return pos - haystack;
    }
    return -1;
}

long native_substr(long *args, int argc) {
    static char empty_str[] = "";
    if (!args || argc < 3) {
        return (long)empty_str;
    }
    char *str = (char*)args[0];
    if (!str) {
        return (long)empty_str;
    }
    int start = (int)args[1];
    int length = (int)args[2];

    if (str_pool_idx >= STR_POOL_SIZE) {
        error("String pool overflow");
        return (long)empty_str;
    }

    char *result = &str_pool[str_pool_idx];
    int str_len = strlen(str);

    if (start < 0) start = 0;
    if (start >= str_len) return (long)empty_str;
    if (start + length > str_len) length = str_len - start;
    if (length < 0) return (long)empty_str;

    if (str_pool_idx + length + 1 >= STR_POOL_SIZE) {
        error("String pool overflow");
        return (long)empty_str;
    }

    strncpy(result, str + start, length);
    result[length] = 0;

    str_pool_idx += length + 1;
    return (long)result;
}

long native_upper(long *args, int argc) {
    static char empty_str[] = "";
    if (!args || argc < 1) {
        return (long)empty_str;
    }
    char *str = (char*)args[0];
    if (!str) {
        return (long)empty_str;
    }

    if (str_pool_idx >= STR_POOL_SIZE) {
        error("String pool overflow");
        return (long)empty_str;
    }

    char *result = &str_pool[str_pool_idx];
    int len = strlen(str);

    if (str_pool_idx + len + 1 >= STR_POOL_SIZE) {
        error("String pool overflow");
        return (long)empty_str;
    }

    for (int i = 0; i <= len; i++) {
        result[i] = toupper(str[i]);
    }

    str_pool_idx += len + 1;
    return (long)result;
}

long native_lower(long *args, int argc) {
    static char empty_str[] = "";
    if (!args || argc < 1) {
        return (long)empty_str;
    }
    char *str = (char*)args[0];
    if (!str) {
        return (long)empty_str;
    }

    if (str_pool_idx >= STR_POOL_SIZE) {
        error("String pool overflow");
        return (long)empty_str;
    }

    char *result = &str_pool[str_pool_idx];
    int len = strlen(str);

    if (str_pool_idx + len + 1 >= STR_POOL_SIZE) {
        error("String pool overflow");
        return (long)empty_str;
    }

    for (int i = 0; i <= len; i++) {
        result[i] = tolower(str[i]);
    }

    str_pool_idx += len + 1;
    return (long)result;
}

long native_strip(long *args, int argc) {
    static char empty_str[] = "";
    if (!args || argc < 1) {
        return (long)empty_str;
    }
    char *str = (char*)args[0];
    if (!str) {
        return (long)empty_str;
    }

    if (str_pool_idx >= STR_POOL_SIZE) {
        error("String pool overflow");
        return (long)empty_str;
    }

    char *result = &str_pool[str_pool_idx];

    while (*str && isspace(*str)) str++;

    int len = strlen(str);
    while (len > 0 && isspace(str[len - 1])) len--;

    if (str_pool_idx + len + 1 >= STR_POOL_SIZE) {
        error("String pool overflow");
        return (long)empty_str;
    }

    strncpy(result, str, len);
    result[len] = 0;

    str_pool_idx += len + 1;
    return (long)result;
}

long native_replace(long *args, int argc) {
    static char empty_str[] = "";
    if (!args || argc < 3) {
        return (long)empty_str;
    }
    char *str = (char*)args[0];
    char *old_str = (char*)args[1];
    char *new_str = (char*)args[2];
    if (!str || !old_str || !new_str) {
        return (long)empty_str;
    }

    if (str_pool_idx >= STR_POOL_SIZE) {
        error("String pool overflow");
        return (long)empty_str;
    }

    char *result = &str_pool[str_pool_idx];
    char *src = str;
    char *dst = result;
    int old_len = strlen(old_str);
    int new_len = strlen(new_str);

    if (old_len == 0) {
        int str_len = strlen(str);
        if (str_pool_idx + str_len + 1 >= STR_POOL_SIZE) {
            error("String pool overflow");
            return (long)empty_str;
        }
        strcpy(result, str);
        str_pool_idx += str_len + 1;
        return (long)result;
    }

    while (*src) {
        if (strncmp(src, old_str, old_len) == 0) {
            int remaining = strlen(src + old_len);
            int current_pos = dst - result;
            if (str_pool_idx + current_pos + new_len + remaining + 1 >= STR_POOL_SIZE) {
                error("String pool overflow");
                *dst = 0;
                str_pool_idx += current_pos + 1;
                return (long)result;
            }
            strcpy(dst, new_str);
            dst += new_len;
            src += old_len;
        } else {
            *dst++ = *src++;
        }
    }
    *dst = 0;

    int total_len = dst - result;
    str_pool_idx += total_len + 1;
    return (long)result;
}

long native_startswith(long *args, int argc) {
    if (!args || argc < 2) {
        return 0;
    }
    char *str = (char*)args[0];
    char *prefix = (char*)args[1];
    if (!str || !prefix) {
        return 0;
    }
    int prefix_len = strlen(prefix);
    return strncmp(str, prefix, prefix_len) == 0;
}

long native_endswith(long *args, int argc) {
    if (!args || argc < 2) {
        return 0;
    }
    char *str = (char*)args[0];
    char *suffix = (char*)args[1];
    if (!str || !suffix) {
        return 0;
    }
    int str_len = strlen(str);
    int suffix_len = strlen(suffix);

    if (suffix_len > str_len) return 0;
    return strcmp(str + str_len - suffix_len, suffix) == 0;
}

void register_native_functions() {
    register_native_func("socket", native_socket);
    register_native_func("bind", native_bind);
    register_native_func("listen", native_listen);
    register_native_func("accept", native_accept);
    register_native_func("recv", native_recv);
    register_native_func("send", native_send);
    register_native_func("close", native_close);
    register_native_func("strlen", native_strlen);
    register_native_func("AF_INET", native_AF_INET);
    register_native_func("SOCK_STREAM", native_SOCK_STREAM);
    register_native_func("sqrt", native_sqrt);
    register_native_func("pow", native_pow);
    register_native_func("sin", native_sin);
    register_native_func("cos", native_cos);
    register_native_func("tan", native_tan);
    register_native_func("abs", native_abs);
    register_native_func("floor", native_floor);
    register_native_func("ceil", native_ceil);
    register_native_func("strpos", native_strpos);
    register_native_func("substr", native_substr);
    register_native_func("upper", native_upper);
    register_native_func("lower", native_lower);
    register_native_func("strip", native_strip);
    register_native_func("replace", native_replace);
    register_native_func("startswith", native_startswith);
    register_native_func("endswith", native_endswith);
}