#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <sqlite3.h>

inline char *get_filename(const char *c) {
    char *qout = "queries/mranks.sql"; 
    if (c != NULL) {
        switch(*c) {
            case 'm':
                qout = "queries/mleaderboard-ojoin.sql";
                break;
            case 'p':
                qout = "queries/rplayers.sql";
                break;
            case 't':
                qout = "queries/test.txt";
                break;
        }
    }
    return qout;
}

inline void print_tblheader(const char *c) {
    char *labels;
    switch (*c) {
        default:
            labels = "<TABLE class='center'>\
             <TH class='tablename' COLSPAN='4'> <H3><BR>Map List</H3> </TH>\
             <TR>\
             <TH class='columnname'>Name</TH>\
             <TH class='columnname'>Records</TH>\
             <TH class='columnname'>Best Time</TH>\
             <TH class='columnname'>Held By</TH>\
             </TR>";
            break;
        case 'm':
            labels = "<TABLE class='center'>\
                     <TH class='tablename' COLSPAN='3'><H3><BR>Leaderboard</H3></TH>\
                     <TR>\
                     <TH class='columnname'>Rank</TH>\
                     <TH class='columnname'>Name</TH>\
                     <TH class='columnname'>Time</TH>\
                     </TR>";
            break;
        case 'p':
            labels = "<TABLE class='center'>\
                 <TH class='tablename' COLSPAN='3'> <H3><BR>Ranks</H3> </TH>\
                 <TR>\
                 <TH class='columnname'>Name</TH>\
                 <TH class='columnname'>Map</TH>\
                 <TH class='columnname'>Rank</TH>\
                 </TR>";
            break;
    }
    printf("%s", labels);
}

// input is an integer as a string.
// the time is in centiseconds.
// this means the longest XDF run this can support is
// 21,474,836.47 seconds
// someone would need to idle in-game for 248 days
void print_time(const unsigned char *strcs) {
    const unsigned int num = strtoul((const char*)strcs, NULL, 10);
    unsigned int s = num/100;
    const unsigned int cs  = num % 100;
    const unsigned int min = s/60;
    s = s % 60;
    if (min > 0) {
        printf("<TD>%u:%.2u.%.2u</TD>", min, s, cs);
    } else {
        printf("<TD>%u.%.2u</TD>", s, cs);
    }
}

// display and format the results of the query.
void qresult(sqlite3_stmt * const sp, const char *c) {
    int e;
    unsigned int i;
    unsigned int cc  = sqlite3_column_count(sp);
    print_tblheader(c);
    while ((e = sqlite3_step(sp)) == SQLITE_ROW) {
        printf("<TR>");
        for (i = 0; i < cc; i++) {
            if ((*c == 'm' && i == 1) || (*c == '\0' && i == 3) || (*c == 'p' && i == 0)) { 
                printf("<TD>%s</TD>", sqlite3_column_text(sp, i));
            } else if ((i == 0 && *c == '\0') || (i == 1 && *c == 'p') ) {
                printf("<TD><a href='/cgi/cts.py?map=%s'>%s</a></TD>", sqlite3_column_text(sp, i), sqlite3_column_text(sp, i));
            } else if (i == 2 && (*c == 'm' || *c == '\0')) {
                print_time(sqlite3_column_text(sp, i));
            } else {
                printf("<TD>%s</TD>", sqlite3_column_text(sp, i));
            }
        }
        printf("</TR>");
    }
    printf("</TABLE>");
}

// const char 'sql' is never NULL.
// const char 'str' may be NULL, however it is only when 
// the contents of mranks.sql is in const char 'sql'.
bool executequery(const char *sql, const char *str) {
    const char *p = (str != NULL) ? strchr(str, '=') + 1 : NULL;
    const char qc = (str != NULL) ? str[0] : '\0';
    sqlite3    *db;
    int con = sqlite3_open("db/cts.db", &db);
    if (con != SQLITE_OK) {
        fprintf(stderr, "Can not open database: %s\n", sqlite3_errmsg(db));
        return false;
    }
    sqlite3_stmt *s;
    // prepare sql to s, reading until null character.
    con = sqlite3_prepare_v2(db, sql, -1, &s, NULL);
    if (con != SQLITE_OK) {
        fprintf(stderr, "Could not prepare SQL statement: %s\n", sqlite3_errmsg(db));
        return false;
    }
    // bind parameter with a string length that is the # of bytes to null char.
    con = sqlite3_bind_text(s, 1, p, -1, NULL);
    qresult(s, &qc);
    sqlite3_finalize(s);
    sqlite3_close(db);
    return true;
}

// both allocates and frees memory used up by the string..
// containing the data from query files.
void getquery(const char *qs) {
    char *qf = NULL;
    char *fname = get_filename(qs);
    if (fname != NULL) { 
        FILE *f = fopen(fname, "r");
        if (f != NULL) {
            // change from fseek/SEEK_END when sql queries are >2 GB in size.
            fseek(f, 0, SEEK_END);         // go to the end of file
            unsigned int size = ftell(f);
            qf = calloc(size, sizeof(char));
            if (qf != NULL) {
                fseek(f, 0, SEEK_SET);     // go to the start of file
                fread(qf, sizeof(char), size, f);
            }
        }
        fclose(f);
    }
    executequery(qf, qs);
    free(qf);
}

void html(void) {
    const char *html_top = "Content-Type: text/html\n\n\
              <html><head><meta content=\"text/html; charset=UTF-8\" />\
              <link rel=\"stylesheet\" type=\"text/css\" href=\"page.css\">\
              <title>/v/ - Xonotic</title>\
              <p class='hidden'>:-) / nice one<br></p>";
    const char *html_bot = "<br><br><p classname='footer'>Pages under construction.<br>\
              Service may sporadically become unavailable.<br>\
              In-game database is not directly synced with this web server.\
              </p>\
              </body></html>";
    printf("%s", html_top);
//    getquery(getenv("QUERY_STRING"));
//    getquery("map=pornstar-kaine");
    getquery(NULL);
    printf("%s", html_bot);
}

int main(void) {
    html();
//    getquery("player=duHTyaSGpdTk7oebwPFoo899xPoTwP9bja4DUjCjTLo=");
    return 0;
}