#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <gctypes.h>
#include "gettext.h"

typedef struct _MSG
{
    u32 id;
    char* msgstr;
    struct _MSG *next;
} MSG;
static MSG *baseMSG = 0;

#define HASHWORDBITS 32

/* Defines the so called `hashpjw' function by P.J. Weinberger
 [see Aho/Sethi/Ullman, COMPILERS: Principles, Techniques and Tools,
 1986, 1987 Bell Telephone Laboratories, Inc.]  */
static inline u32 hash_string(const char *str_param)
{
    u32 hval, g;
    const char *str = str_param;

    /* Compute the hash value for the given string.  */
    hval = 0;
    while (*str != '\0')
    {
        hval <<= 4;
        hval += (u8) *str++;
        g = hval & ((u32) 0xf << (HASHWORDBITS - 4));
        if (g != 0)
        {
            hval ^= g >> (HASHWORDBITS - 8);
            hval ^= g;
        }
    }
    return hval;
}

/* Expand some escape sequences found in the argument string.  */
static char *
expand_escape(const char *str)
{
    char *retval, *rp;
    const char *cp = str;

    retval = (char *) malloc(strlen(str) + 1);
    if (retval == NULL) return NULL;
    rp = retval;

    while (cp[0] != '\0' && cp[0] != '\\')
        *rp++ = *cp++;
    if (cp[0] == '\0') goto terminate;
    do
    {

        /* Here cp[0] == '\\'.  */
        switch (*++cp)
        {
            case '\"': /* " */
                *rp++ = '\"';
                ++cp;
                break;
            case 'a': /* alert */
                *rp++ = '\a';
                ++cp;
                break;
            case 'b': /* backspace */
                *rp++ = '\b';
                ++cp;
                break;
            case 'f': /* form feed */
                *rp++ = '\f';
                ++cp;
                break;
            case 'n': /* new line */
                *rp++ = '\n';
                ++cp;
                break;
            case 'r': /* carriage return */
                *rp++ = '\r';
                ++cp;
                break;
            case 't': /* horizontal tab */
                *rp++ = '\t';
                ++cp;
                break;
            case 'v': /* vertical tab */
                *rp++ = '\v';
                ++cp;
                break;
            case '\\':
                *rp = '\\';
                ++cp;
                break;
            case '0':
            case '1':
            case '2':
            case '3':
            case '4':
            case '5':
            case '6':
            case '7':
            {
                int ch = *cp++ - '0';

                if (*cp >= '0' && *cp <= '7')
                {
                    ch *= 8;
                    ch += *cp++ - '0';

                    if (*cp >= '0' && *cp <= '7')
                    {
                        ch *= 8;
                        ch += *cp++ - '0';
                    }
                }
                *rp = ch;
            }
                break;
            default:
                *rp = '\\';
                break;
        }

        while (cp[0] != '\0' && cp[0] != '\\')
            *rp++ = *cp++;
    } while (cp[0] != '\0');

    /* Terminate string.  */
    terminate: *rp = '\0';
    return retval;
}

static MSG *findMSG(u32 id)
{
    MSG *msg;
    for (msg = baseMSG; msg; msg = msg->next)
    {
        if (msg->id == id) return msg;
    }
    return NULL;
}

static MSG *setMSG(const char *msgid, const char *msgstr)
{
    u32 id = hash_string(msgid);
    MSG *msg = findMSG(id);
    if (!msg)
    {
        msg = (MSG *) malloc(sizeof(MSG));
        msg->id = id;
        msg->msgstr = NULL;
        msg->next = baseMSG;
        baseMSG = msg;
    }
    if (msg)
    {
        if (msgstr)
        {
            if (msg->msgstr) free(msg->msgstr);
            //msg->msgstr = strdup(msgstr);
            msg->msgstr = expand_escape(msgstr);
        }
        return msg;
    }
    return NULL;
}
void gettextCleanUp(void)
{
    while (baseMSG)
    {
        MSG *nextMsg = baseMSG->next;
        free(baseMSG->msgstr);
        free(baseMSG);
        baseMSG = nextMsg;
    }
}

bool gettextLoadLanguage(const char* langFile)
{
    FILE *f;
    char line[512];
    char *lastID = NULL;

    gettextCleanUp();
    f = fopen(langFile, "r");
    if (!f) return false;

    while (fgets(line, sizeof(line), f))
    {
        // lines starting with # are comments
        if (line[0] == '#')
            continue;
        else if (strncmp(line, "msgid \"", 7) == 0)
        {
            char *msgid, *end;
            if (lastID)
            {
                free(lastID);
                lastID = NULL;
            }
            msgid = &line[7];
            end = strrchr(msgid, '"');
            if (end && end - msgid > 1)
            {
                *end = 0;
                lastID = strdup(msgid);
            }
        }
        else if (strncmp(line, "msgstr \"", 8) == 0)
        {
            char *msgstr, *end;

            if (lastID == NULL) continue;

            msgstr = &line[8];
            end = strrchr(msgstr, '"');
            if (end && end - msgstr > 1)
            {
                *end = 0;
                setMSG(lastID, msgstr);
            }
            free(lastID);
            lastID = NULL;
        }

    }

    fclose(f);
    return true;
}
const char *gettext(const char *msgid)
{
    MSG *msg = findMSG(hash_string(msgid));
    if (msg && msg->msgstr) return msg->msgstr;
    return msgid;
}