#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "parslib.h"
#include "streecmp/streecmp.h"

extern char *methods;
extern char *headers;

static struct nod *method_tree = NULL;
static struct nod *header_tree = NULL; 

static int stoin(char *str, int len, int *out) {
    int ret = 0; 
    int place = 1; 
    for (char *chr = str+len-1; chr >= str; chr--) {
        if (chr == str) {
            if (*chr == '+') {
                goto _proceed;
            }
            if (*chr == '-') {
                goto _proceed;
            }
        }
        if (*chr >= '0' && *chr <= '9') {
            goto _proceed;
        }

        return -1;

_proceed:

        if (*chr == '-') {
            ret = -ret;
            continue;
        }
        if (*chr == '+') {
            continue;
        }

        int number = *chr-'0'; 
        ret += number * place; 
        place *= 10; 
    }

    *out = ret;
    return 0;
}

void printfpareq(struct httpareq *req) {
    fprintf(stderr, "\tstats:\n"
                    "\t\tmethod\t: %d\n"
                    "\t\turi\t: %.*s\n"
                    "\t\tver\t: %.*s\n",
                    req->titl.method, 
                    req->titl.uri.len, req->titl.uri.er, 
                    req->titl.ver.len, req->titl.ver.er
            );

    fprintf(stdout, "\theaders:\n");
    for (int i = 0; i < header_count; i++) {
        struct point *pnt = &req->hentries[i]; 
        if (!pnt->er) {
            continue;
        }

        fprintf(stdout, "\t\t%d\t: %.*s\n", i, pnt->len, pnt->er);
    }
}

void printfpares(struct httpares *res) {
    fprintf(stderr, "\tstats:\n"
                    "\t\tver\t: %.*s\n"
                    "\t\tcode\t: %d\n"
                    "\t\tstext\t: %.*s\n",
                    res->titl.ver.len, res->titl.ver.er,
                    res->titl.code, 
                    res->titl.stxt.len, res->titl.stxt.er
            );

    fprintf(stdout, "\theaders:\n");
    for (int i = 0; i < header_count; i++) {
        struct point *pnt = &res->hentries[i]; 
        if (!pnt->er) {
            continue;
        }

        fprintf(stdout, "\t\t%d\t: %.*s\n", i, pnt->len, pnt->er);
    }
}

int initres(void) {
    int ret = 0;

    header_tree = allocnod();
    if (!header_tree) {
        return -1;
    }

    method_tree = allocnod();
    if (!method_tree) {
        return -1;
    }

    ret = gentree(header_tree, headers, NULL);
    if (ret < 0) {
        return -1;
    }

    ret = gentree(method_tree, methods, NULL);
    if (ret < 0) {
        return -1;
    }

    return 0;
}

void fretres(void) {
    frenod(method_tree);
    frenod(header_tree);
}

void frepareq(struct httpareq *req) {
    struct httitlereq *titl = &req->titl;
    free(titl->uri.er);
    free(titl->ver.er);

    for (int i = 0; i < header_count; i++) {
        struct point *e = &req->hentries[i];
        if (!e->er) {
            continue;
        }

        free(e->er);
    }
}

void frepares(struct httpares *res) {
    struct httitleres *titl = &res->titl;
    free(titl->ver.er);
    free(titl->stxt.er);

    for (int i = 0; i < header_count; i++) {
        struct point *e = &res->hentries[i];
        if (!e->er) {
            continue;
        }

        free(e->er);
    }
}

int readlin(char **buff, char **buff_lim) {
    int diff = 0; 
    if ((*buff) >= (*buff_lim)) {
        return diff;
    }

    int ret = 0; 
    char *match = strstr(*buff, "\r\n");
    if (match) {
        ret = match-(*buff);
        *buff += 2;
    } else {
        ret = (*buff_lim)-(*buff);
    }
    *buff += ret;
    return ret;
}

int parshfield(char *offset, int len, struct point *hentries) {
    int key = 0; 
    int ret = 0; 
    int diff = 0; 

    char *cursor = offset;
    char *cursor_lim = offset+len;

    // header title
    char *htitle_lim = strchr(cursor, ':');
    if (!htitle_lim) {
        return -1;
    }
    if (htitle_lim > cursor_lim) {
        return -1;
    }

    diff = htitle_lim-cursor;
    ret = streencmp(header_tree, cursor, diff);
    if (!ret) {
        return 0; // skip it 
    }

    key = ret;
    cursor += diff;

    // white space and seperators 
_loop: 
    if (cursor > cursor_lim) {
        return -1;
    }
    if (*cursor == ':') {
        cursor++; 
        goto _loop; 
    }
    if (*cursor == ' ') {
        cursor++;
        goto _loop;
    }

    // header value
    diff = cursor_lim-cursor;
    char *e = strndup(cursor, diff);
    if (!e) {
        return -1;
    }

    hentries[key].er = e;
    hentries[key].len = diff;

    return 0;
}

int pareqtitl(char *offset, int len, struct httitlereq *titl) {
    int ret = 0; 
    int diff = 0; 
    char *cursor = offset;
    char *cursor_lim = cursor+len;

    // method
    char *method_lim = strchr(cursor, ' ');
    if (!method_lim) {
        return -1;
    }
    if (method_lim > cursor_lim) {
        return -1;
    }

    diff = method_lim-cursor;
    ret = streencmp(method_tree, cursor, diff);
    if (ret == 0) {
        return -1;
    }

    titl->method = ret;
    cursor += diff;

    // white space 
_loop1: 
    if (cursor > cursor_lim) {
        return -1;
    }
    if (*cursor == ' ') {
        cursor++;
        goto _loop1;
    }

    // uri 
    char *uri_lim = strchr(cursor, ' ');
    if (!uri_lim) {
        return -1;
    }
    if (uri_lim > cursor_lim) {
        return -1;
    }

    diff = uri_lim-cursor;
    char *e = strndup(cursor, diff);
    if (!e) {
        return -1;
    }

    titl->uri.er = e;
    titl->uri.len = diff;

    cursor += diff;
    
    // white space 
_loop2:
    if (cursor > cursor_lim) {
        return -1;
    }
    if (*cursor == ' ') {
        cursor++;
        goto _loop2;
    }

    // ver
    diff = cursor_lim-cursor;
    e = strndup(cursor, diff); 
    if (!e) {
        return -1;
    }

    titl->ver.er = e;
    titl->ver.len = diff;

    cursor += diff;

    return 0;
}

int parestitl(char *offset, int len, struct httitleres *titl) {
    int ret = 0; 
    int diff = 0;
    char *cursor = offset; 
    char *cursor_lim = cursor+len; 

    // ver 
    char *ver_lim = strchr(cursor, ' ');
    if (!ver_lim) {
        return -1;
    }
    if (ver_lim > cursor_lim) {
        return -1;
    }

    diff = ver_lim-cursor;
    char *e = strndup(cursor, diff); 
    if (!e) {
        return -1;
    }

    titl->ver.er = e;
    titl->ver.len = diff;

    cursor += diff;

    // white space 
_loop1:
    if (cursor > cursor_lim) {
        return -1;
    }
    if (*cursor == ' ') {
        cursor++;
        goto _loop1;
    }

    // code 
    char *code_lim = strchr(cursor, ' ');
    if (!code_lim) {
        return -1;
    }
    if (code_lim > cursor_lim) {
        return -1;
    }

    diff = code_lim-cursor;
    int code;
    ret = stoin(cursor, diff, &code);
    if (ret < 0) {
        return -1;
    }

    titl->code = code;
    cursor += diff;

    // white space 
_loop2: 
    if (cursor > cursor_lim) {
        return -1;
    }
    if (*cursor == ' ') {
        cursor++; 
        goto _loop2;
    }

    // status text
    diff = cursor_lim-cursor;
    e = strndup(cursor, diff);
    if (!e) {
        return -1;
    }

    titl->stxt.er = e;
    titl->stxt.len = diff;

    cursor += diff;

    return 0;
}

int pareq(char *buff, struct httpareq *req) {
    int ret; 
    char *buff_lim = buff+strlen(buff);

    char *title_offset = buff;
    int title_len = readlin(&buff, &buff_lim);
    if ((ret = pareqtitl(title_offset, title_len, &req->titl)) < 0) {
        fprintf(stderr, "Failed parsing title\n");
        return -1;
    }

    for (int bound = 0; bound < MAX_BOUND; bound++) {
        char *header_offset = buff; 
        int header_len = readlin(&buff, &buff_lim);
        char *header_limit = header_offset+header_len;
        
        // IF END OF MESSAGE
        if (!header_len) {
            break;
        }

        if ((ret = parshfield(header_offset, 
                        header_len, 
                        req->hentries)) < 0) {
            fprintf(stderr, "Failed parsing header\n");
            return -1;
        }
    }

    return 0;
}

int pares(char *buff, struct httpares *res) {
    int ret; 
    char *buff_lim = buff+strlen(buff);

    char *title_offset = buff;
    int title_len = readlin(&buff, &buff_lim);
    if ((ret = parestitl(title_offset, title_len, &res->titl)) < 0) {
        fprintf(stderr, "Failed parsing title\n");
        return -1;
    }

    for (int bound = 0; bound < MAX_BOUND; bound++) {
        char *header_offset = buff; 
        int header_len = readlin(&buff, &buff_lim);
        char *header_limit = header_offset+header_len;
        
        // IF END OF MESSAGE
        if (!header_len) {
            break;
        }

        if ((ret = parshfield(header_offset, 
                        header_len, 
                        res->hentries)) < 0) {
            fprintf(stderr, "Failed parsing header\n");
            return -1;
        }
    }

    return 0;
}