#include "sckulya.h"

int64_t tri_sqlite_open(TString filename, TString *error) {
    sqlite3* out_db = 0;

    int rc = sqlite3_open((const char*) filename->body, &out_db);
    
    if(rc != SQLITE_OK) {
        if(out_db) {
            sqlite3_close(out_db);
        }

        const char* msg = sqlite3_errmsg(out_db);

        if(!msg) {
            msg = "Unknown error";
        }

        int64_t len = (int64_t)strlen(msg);
        *error = tri_newString(len, len, (char*)msg);
    }

    sqlite3_busy_timeout(out_db, 5000);

    return (int64_t) out_db;
}

int tri_sqlite_close(int64_t db) {
    if (!db) return SQLITE_MISUSE;
    return sqlite3_close((sqlite3*) db);
}

void tri_sqlite_exec(int64_t db, TString query, TString *error) {
    char* errmsg = NULL;
    int rc = sqlite3_exec((sqlite3*) db, (const char*) query->body, NULL, NULL, &errmsg);

    if (errmsg) {
        int64_t len = (int64_t)strlen(errmsg);
        *error = tri_newString(len, len, errmsg);

        sqlite3_free(errmsg);
    }
}

void escape_and_append (const unsigned char *s, char* buf, size_t* len) {
for (; *s; ++s) {
    char esc = 0;

    switch (*s) {
        case '\\': esc = '\\'; break;
        case '\b': esc = 'b'; break;
        case '\f': esc = 'f'; break;
        case '\n': esc = 'n'; break;
        case '\r': esc = 'r'; break;
        case '\t': esc = 't'; break;
        default: break;
    }
    if (esc) {
        buf[(*len)++] = '\\';
        buf[(*len)++] = esc;
    } else {
        buf[(*len)++] = *s;
    }
}
};

int tri_sqlite_query(int64_t db, TString query, TString *result, TString *error) {
    sqlite3_stmt *stmt = NULL;
    int rc = sqlite3_prepare_v2((sqlite3*)db, (const char*) query->body, -1, &stmt, NULL);
    if (rc != SQLITE_OK) {
        if (error) {
            const char *msg = sqlite3_errmsg((sqlite3*)db);
            if (!msg) msg = "Unknown error";
            int64_t len = (int64_t)strlen(msg);
            *error = tri_newString(len, len, (char*)msg);
        }
        return rc;
    }

    size_t cap = 1024;
    size_t len = 0;
    char *buf = malloc(cap);

    if (!buf) {
        sqlite3_finalize(stmt);
        if (error) *error = tri_newString(0,0,"Out of memory");
        return SQLITE_NOMEM;
    }

    buf[len++] = '[';
    int first_row = 1;

    while ((rc = sqlite3_step(stmt)) == SQLITE_ROW) {
        if (!first_row) { buf[len++] = ','; } else first_row = 0;
        buf[len++] = '{';

        int ncol = sqlite3_column_count(stmt);
        for (int i = 0; i < ncol; ++i) {
            if (i) { buf[len++] = ','; }
            const char *colname = sqlite3_column_name(stmt, i);
            /* "colname": */
            // strlen(colname) + 4;
            buf[len++] = '\"';
            escape_and_append((const unsigned char*)colname, buf, &len);
            buf[len++] = '\"';
            buf[len++] = ':';

            int type = sqlite3_column_type(stmt, i);
            if (type == SQLITE_INTEGER) {
                long long v = sqlite3_column_int64(stmt, i);
                char tmp[32];
                int n = snprintf(tmp, sizeof(tmp), "%lld", v);
                memcpy(buf + len, tmp, n); len += n;
            } else if (type == SQLITE_FLOAT) {
                double v = sqlite3_column_double(stmt, i);
                char tmp[64];
                int n = snprintf(tmp, sizeof(tmp), "%g", v);
                memcpy(buf + len, tmp, n); len += n;
            } else if (type == SQLITE_NULL) {
                memcpy(buf + len, "null", 4); len += 4;
            } else {
                const unsigned char *txt = sqlite3_column_text(stmt, i);
                if (!txt) {
                    memcpy(buf + len, "null", 4); len += 4;
                } else {
                    buf[len++] = '\"';
                    escape_and_append(txt, buf, &len);
                    buf[len++] = '\"';
                }
            }
        }

        buf[len++] = '}';
    }

    /* finalize and handle errors */
    if (rc != SQLITE_DONE) {
        const char *msg = sqlite3_errmsg((sqlite3*)db);
        if (error) {
            if (!msg) msg = "Unknown error";
            int64_t mlen = (int64_t)strlen(msg);
            *error = tri_newString(mlen, mlen, (char*)msg);
        }
        sqlite3_finalize(stmt);
        free(buf);
        return rc;
    }

    buf[len++] = ']';
    buf[len] = '\0';

    sqlite3_finalize(stmt);

    if (result) {
        *result = tri_newString((int64_t)len, (int64_t)len, buf);
    }

    free(buf);
    return SQLITE_OK;
}