#include "arctic.h"

#include <string.h>

const char ARCTIC_CODE_PAGE[97] =
    "0123456789ABCDEF"
    "GHIJKLMNOPQRSTUV"
    "WXYZabcdefghijkl"
    "mnopqrstuvwxyz_."
    "+-*/%\\|$@<{=}>,;"
    "&^![]?~:()'\"` #\n"
;

/* ops with an immediate argument */
#define FOR_IMMEDIATE_OPS(X) \
    X('0') X('G') X('H') X('L') X('M') X('P') X('Q') X('d') X('o') X('u') \
    X('@') X('<') X('{') X('=') X('}') X('>') X(',') X(';') X('[') X(']')

#define FOR_PLAIN_OPS(X) \
    X('1') X('2') X('3') X('4') X('5') X('6') X('7') X('8') X('9') X('A') \
    X('B') X('C') X('D') X('E') X('F') X('I') X('J') X('K') X('N') X('O') \
    X('R') X('S') X('U') X('V') X('W') X('X') X('Y') X('Z') X('a') X('b') \
    X('c') X('e') X('f') X('g') X('h') X('i') X('j') X('k') X('l') X('m') \
    X('n') X('p') X('q') X('r') X('s') X('t') X('v') X('w') X('x') X('y') \
    X('z') X('_') X('.') X('+') X('-') X('*') X('/') X('%') X('\\') X('|') \
    X('&') X('^') X('!') X('?') X('(') X(')') X('`')

#define CASE(X, ...) case X:

#define chrncat(str, chr, n, fail) do { \
    char *last; \
    for (last = str; *last; last++) { \
        if (last >= str + n) { \
            fail; \
        } \
    } \
    *last++ = chr; \
    *last = 0; \
} while (0)

enum ArcticErrorCode arctic_scan(struct ArcticScanner *scanner, char next) {
    switch (scanner->buf[0]) {
        case 0: /* initial state */
            switch (next) {
                case ' ':
                    return ARCTIC_OK;

                FOR_IMMEDIATE_OPS(CASE)
                case '#':
                case ':':
                case '\"':
                case '\'':
                    scanner->buf[0] = next;
                    scanner->buf[1] = 0;
                    return ARCTIC_OK;

                FOR_PLAIN_OPS(CASE)
                case '\n':
                    scanner->op_callback(next, 0, scanner->data);
                    return ARCTIC_OK;

                default:
                    return ARCTIC_UNEXPECTED_CHAR;
            }

        case '#': /* comment */
            if (next == '\n')
                scanner->buf[0] = 0;
            return ARCTIC_OK;

        case '"': /* section switch */
            if (next == '"') {
                scanner->section_callback(scanner->buf + 1, scanner->data);
                scanner->buf[0] = 0;
            } else {
                chrncat(
                    scanner->buf, next, ARCTIC_BUFSIZE,
                    return ARCTIC_BUFFER_FULL
                );
            }
            return ARCTIC_OK;

        case ':': /* label name */
            if (next == ' ' || next == '\n' || next == '#') {
                scanner->label_callback(scanner->buf + 1, scanner->data);
                scanner->buf[0] = (next == '#' ? '#' : 0);
            } else {
                chrncat(
                    scanner->buf, next, ARCTIC_BUFSIZE,
                    return ARCTIC_BUFFER_FULL
                );
            }
            return ARCTIC_OK;

        case '\'': /* data injection */
            if (next == '\'') {
                scanner->data_callback(scanner->buf + 1, scanner->data);
                scanner->buf[0] = 0;
            } else {
                chrncat(
                    scanner->buf, next, ARCTIC_BUFSIZE,
                    return ARCTIC_BUFFER_FULL
                );
            }
            return ARCTIC_OK;

        FOR_IMMEDIATE_OPS(CASE) /* immediate ops */
            if (next == ' ' || next == '\n' || next == '#') {
                scanner->op_callback(scanner->buf[0], scanner->buf + 1, scanner->data);
                scanner->buf[0] = (next == '#' ? '#' : 0);
            } else {
                chrncat(
                    scanner->buf, next, ARCTIC_BUFSIZE,
                    return ARCTIC_BUFFER_FULL
                );
            }
            return ARCTIC_OK;

        default:
            return ARCTIC_INVALID_STATE;
    }
}