path: root/kon/konscript.c

/* SPDX-License-Identifier: MIT */
/*
 * konscript.c
 *
 * Copyright (c) 2026 KonAki
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include "konscript.h"

#include <stddef.h>

/*** variables ***/

int kon_scriptSwitch(const kon_script_t *vm, int id)
{
	return id >= 0 && id < vm->switchCount && vm->switches && vm->switches[id] ? 1 : 0;
}

int32_t kon_scriptVar(const kon_script_t *vm, int id)
{
	return id >= 0 && id < vm->varCount && vm->vars ? vm->vars[id] : 0;
}

void kon_scriptSetSwitch(kon_script_t *vm, int id, int on)
{
	if (id >= 0 && id < vm->switchCount && vm->switches) vm->switches[id] = on ? 1 : 0;
}

void kon_scriptSetVar(kon_script_t *vm, int id, int32_t value)
{
	if (id >= 0 && id < vm->varCount && vm->vars) vm->vars[id] = value;
}

/* done in 64 bits and clamped so a script can never overflow or divide by 0 */
static int32_t arithmetic(int32_t x, int how, int32_t y)
{
	int64_t r;

	switch (how) {
	case KON_ADD: r = (int64_t)x + y; break;
	case KON_SUB: r = (int64_t)x - y; break;
	case KON_MUL: r = (int64_t)x * y; break;
	case KON_DIV: r = y ? (int64_t)x / y : x; break;
	case KON_MOD: r = y ? (int64_t)x % y : x; break;
	default: r = y; break;
	}
	if (r > INT32_MAX) r = INT32_MAX;
	if (r < INT32_MIN) r = INT32_MIN;
	return (int32_t)r;
}

static int32_t operand(const kon_script_t *vm, int n)
{
	if (n >= KON_VARIABLE && n < KON_VARIABLE + 0x20000000) return kon_scriptVar(vm, n - KON_VARIABLE);
	return n;
}

static int compare(int32_t x, int how, int32_t y)
{
	switch (how) {
	case KON_IS_EQ: return x == y;
	case KON_IS_NE: return x != y;
	case KON_IS_GE: return x >= y;
	case KON_IS_LE: return x <= y;
	case KON_IS_GT: return x > y;
	case KON_IS_LT: return x < y;
	}
	return 0;
}

/*** script ***/

void kon_scriptInit(kon_script_t *vm, const kon_cmd_t *cmds, int count, uint8_t *switches, int switchCount, int32_t *vars, int varCount)
{
	kon_script_t zero = {0};

	*vm = zero;
	vm->cmds = cmds;
	vm->count = cmds && count > 0 ? count : 0;
	vm->switches = switches;
	vm->switchCount = switches && switchCount > 0 ? switchCount : 0;
	vm->vars = vars;
	vm->varCount = vars && varCount > 0 ? varCount : 0;
	vm->status = KON_SCRIPT_DONE;
}

void kon_scriptStart(kon_script_t *vm, int where)
{
	vm->pc = where;
	vm->depth = 0;
	vm->optionCount = 0;
	vm->wait = 0.0f;
	vm->status = where >= 0 && where < vm->count ? KON_SCRIPT_RUNNING : KON_SCRIPT_ERROR;
}

static int menuOptions(kon_script_t *vm, const kon_cmd_t *menu)
{
	int i, n = menu->a;

	vm->optionCount = 0;
	if (n > KON_SCRIPT_MAX_OPTIONS) n = KON_SCRIPT_MAX_OPTIONS;
	for (i = 0; i < n; i++) {
		int at = vm->pc + 1 + i;

		if (at >= vm->count || vm->cmds[at].op != KON_OP_OPTION) return 0;
		if (vm->cmds[at].b >= 0 && !kon_scriptSwitch(vm, vm->cmds[at].b)) continue;
		vm->options[vm->optionCount++] = at;
	}
	return 1;
}

kon_scriptStatus_t kon_scriptRun(kon_script_t *vm)
{
	int steps = 0;

	while (vm->status == KON_SCRIPT_RUNNING) {
		const kon_cmd_t *c;
		int next;

		if (vm->pc < 0 || vm->pc >= vm->count || ++steps > 100000) {
			vm->status = KON_SCRIPT_ERROR;
			break;
		}
		c = &vm->cmds[vm->pc];
		next = vm->pc + 1;
		vm->cmd = vm->pc;

		switch (c->op) {
		case KON_OP_END:
			vm->status = KON_SCRIPT_DONE;
			break;
		case KON_OP_SAY:
			vm->status = KON_SCRIPT_SAY;
			break;
		case KON_OP_MENU:
			if (!menuOptions(vm, c)) {
				vm->status = KON_SCRIPT_ERROR;
				break;
			}
			if (vm->optionCount == 0) {
				next = vm->pc + 1 + (c->a > 0 ? c->a : 0);
				break;
			}
			vm->status = KON_SCRIPT_MENU;
			break;
		case KON_OP_OPTION:
			break;
		case KON_OP_JUMP:
			next = c->a;
			break;
		case KON_OP_SWITCH:
			kon_scriptSetSwitch(vm, c->a, c->b == 2 ? !kon_scriptSwitch(vm, c->a) : c->b);
			break;
		case KON_OP_VAR:
			kon_scriptSetVar(vm, c->a, arithmetic(kon_scriptVar(vm, c->a), c->b, operand(vm, c->c)));
			break;
		case KON_OP_IFSWITCH:
			if (kon_scriptSwitch(vm, c->a) != (c->b ? 1 : 0)) next = c->c;
			break;
		case KON_OP_IFVAR:
			if (!compare(kon_scriptVar(vm, c->a), c->b, operand(vm, c->c))) next = c->d;
			break;
		case KON_OP_WAIT:
			if (c->a > 0) {
				vm->wait = (float)c->a * 0.001f;
				vm->status = KON_SCRIPT_WAIT;
			}
			break;
		case KON_OP_HOST:
			if (vm->host && vm->host(vm, c, vm->user)) vm->status = KON_SCRIPT_HOST;
			break;
		case KON_OP_CALL:
			if (vm->depth >= KON_SCRIPT_MAX_CALLS) {
				vm->status = KON_SCRIPT_ERROR;
				break;
			}
			vm->stack[vm->depth++] = next;
			next = c->a;
			break;
		case KON_OP_RETURN:
			if (vm->depth == 0) vm->status = KON_SCRIPT_DONE;
			else next = vm->stack[--vm->depth];
			break;
		default:
			vm->status = KON_SCRIPT_ERROR;
			break;
		}
		vm->pc = next;
	}
	return vm->status;
}

void kon_scriptUpdate(kon_script_t *vm, float dt)
{
	if (vm->status != KON_SCRIPT_WAIT || !(dt > 0.0f)) return;
	vm->wait -= dt;
	if (vm->wait <= 0.0f) {
		vm->wait = 0.0f;
		vm->status = KON_SCRIPT_RUNNING;
	}
}

void kon_scriptResume(kon_script_t *vm)
{
	if (vm->status == KON_SCRIPT_SAY || vm->status == KON_SCRIPT_HOST) vm->status = KON_SCRIPT_RUNNING;
}

const kon_cmd_t *kon_scriptCurrent(const kon_script_t *vm)
{
	return vm->status == KON_SCRIPT_SAY || vm->status == KON_SCRIPT_HOST ? &vm->cmds[vm->cmd] : NULL;
}

int kon_scriptOptionCount(const kon_script_t *vm)
{
	return vm->status == KON_SCRIPT_MENU ? vm->optionCount : 0;
}

const char *kon_scriptOption(const kon_script_t *vm, int i)
{
	if (vm->status != KON_SCRIPT_MENU || i < 0 || i >= vm->optionCount) return NULL;
	return vm->cmds[vm->options[i]].text;
}

void kon_scriptChoose(kon_script_t *vm, int i)
{
	if (vm->status != KON_SCRIPT_MENU || i < 0 || i >= vm->optionCount) return;
	vm->pc = vm->cmds[vm->options[i]].a;
	vm->optionCount = 0;
	vm->status = KON_SCRIPT_RUNNING;
}

/*** text scripts ***/

#include <string.h>

enum { T_END, T_WORD, T_STRING, T_BAD };

typedef struct lexer {
	const char *s;
	int pos, kind, start, len;
} lexer_t;

typedef struct parse {
	kon_scriptBuild_t *b;
	int pass, line, menu; /* menu is the number of the MENU command while its options are coming, else -1 */
	int ok;
} parse_t;

static void problem(parse_t *p, const char *message)
{
	if (!p->ok) return;
	p->ok = 0;
	p->b->errorLine = p->line;
	strncpy(p->b->error, message, sizeof p->b->error - 1);
	p->b->error[sizeof p->b->error - 1] = '\0';
}

static void lex(lexer_t *l)
{
	while (l->s[l->pos] == ' ' || l->s[l->pos] == '\t' || l->s[l->pos] == '\r') l->pos++;
	if (l->s[l->pos] == '\0' || l->s[l->pos] == '\n' || l->s[l->pos] == '#') {
		l->kind = T_END;
		return;
	}
	if (l->s[l->pos] == '"') {
		l->pos++;
		l->start = l->pos;
		while (l->s[l->pos] != '"') {
			if (l->s[l->pos] == '\0' || l->s[l->pos] == '\n') {
				l->kind = T_BAD;
				return;
			}
			if (l->s[l->pos] == '\\' && l->s[l->pos + 1] != '\0' && l->s[l->pos + 1] != '\n') l->pos++;
			l->pos++;
		}
		l->len = l->pos - l->start;
		l->pos++;
		l->kind = T_STRING;
		return;
	}
	l->start = l->pos;
	while (l->s[l->pos] != '\0' && l->s[l->pos] != '\n' && l->s[l->pos] != ' ' && l->s[l->pos] != '\t' && l->s[l->pos] != '\r' && l->s[l->pos] != '"' && l->s[l->pos] != '#') l->pos++;
	l->len = l->pos - l->start;
	l->kind = T_WORD;
}

static int is(const lexer_t *l, const char *word)
{
	return l->kind == T_WORD && (int)strlen(word) == l->len && strncmp(l->s + l->start, word, (size_t)l->len) == 0;
}

/* a whole number, with a minus if it has one */
static int number(const lexer_t *l, long *out)
{
	int i = 0;
	long v = 0;
	int negative = 0;

	if (l->kind != T_WORD || l->len == 0) return 0;
	if (l->s[l->start] == '-') {
		negative = 1;
		i = 1;
	}
	if (i >= l->len) return 0;
	for (; i < l->len; i++) {
		char c = l->s[l->start + i];

		if (c < '0' || c > '9') return 0;
		if (v > 200000000L) return 0;
		v = v * 10 + (c - '0');
	}
	*out = negative ? -v : v;
	return 1;
}

/* s12 or v3 */
static int reference(const lexer_t *l, char kind, long *out)
{
	lexer_t rest = *l;

	if (l->kind != T_WORD || l->len < 2 || l->s[l->start] != kind) return 0;
	rest.start++;
	rest.len--;
	if (rest.s[rest.start] == '-') return 0;
	return number(&rest, out);
}

static void emit(parse_t *p, int op, int a, int b, int c, int d, const char *text)
{
	kon_scriptBuild_t *bd = p->b;

	if (!p->ok) return;
	if (p->pass == 2) {
		kon_cmd_t *cmd;

		if (bd->count >= bd->maxCmds) {
			problem(p, "too many commands");
			return;
		}
		cmd = &bd->cmds[bd->count];
		cmd->op = op;
		cmd->a = a;
		cmd->b = b;
		cmd->c = c;
		cmd->d = d;
		cmd->text = text;
	}
	bd->count++;
}

/* the string as the pool holds it, with the escapes turned into the letters they stand for */
static const char *keep(parse_t *p, const lexer_t *l)
{
	kon_scriptBuild_t *bd = p->b;
	char *out;
	int i, n = 0;

	if (p->pass == 1) return NULL;
	if (!bd->pool || bd->poolUsed + l->len + 1 > bd->poolSize) {
		problem(p, "out of room for text");
		return NULL;
	}
	out = bd->pool + bd->poolUsed;
	for (i = 0; i < l->len; i++) {
		char c = l->s[l->start + i];

		if (c == '\\' && i + 1 < l->len) {
			c = l->s[l->start + ++i];
			if (c == 'n') c = '\n';
			else if (c == 't') c = '\t';
		}
		out[n++] = c;
	}
	out[n] = '\0';
	bd->poolUsed += n + 1;
	return out;
}

static int labelAt(const kon_scriptBuild_t *b, const char *name, int len)
{
	int i;

	for (i = 0; i < b->labelCount; i++) {
		if ((int)strlen(b->labels[i].name) == len && strncmp(b->labels[i].name, name, (size_t)len) == 0) return b->labels[i].at;
	}
	return -1;
}

int kon_scriptFind(const kon_scriptBuild_t *b, const char *label)
{
	return label ? labelAt(b, label, (int)strlen(label)) : -1;
}

static int target(parse_t *p, lexer_t *l)
{
	int at;

	lex(l);
	if (l->kind != T_WORD) {
		problem(p, "a label is needed");
		return 0;
	}
	if (p->pass == 1) return 0;
	at = labelAt(p->b, l->s + l->start, l->len);
	if (at < 0) {
		problem(p, "unknown label");
		return 0;
	}
	return at;
}

static int nameNumber(const char *const *names, int count, const lexer_t *l)
{
	int i;
	long v;

	if (number(l, &v)) return (int)v;
	for (i = 0; names && i < count; i++) {
		if ((int)strlen(names[i]) == l->len && strncmp(names[i], l->s + l->start, (size_t)l->len) == 0) return i;
	}
	return -2;
}

static void defineLabel(parse_t *p, const lexer_t *l, int len)
{
	kon_scriptBuild_t *b = p->b;

	if (p->pass != 1) return;
	if (len < 1 || len >= KON_SCRIPT_LABEL) {
		problem(p, "label name is empty or too long");
		return;
	}
	if (labelAt(b, l->s + l->start, len) >= 0) {
		problem(p, "label defined twice");
		return;
	}
	if (b->labelCount >= b->maxLabels || !b->labels) {
		problem(p, "too many labels");
		return;
	}
	memcpy(b->labels[b->labelCount].name, l->s + l->start, (size_t)len);
	b->labels[b->labelCount].name[len] = '\0';
	b->labels[b->labelCount].at = b->count;
	b->labelCount++;
}

static void ending(parse_t *p, lexer_t *l)
{
	lex(l);
	if (l->kind != T_END) problem(p, "something extra on the line");
}

static void statement(parse_t *p, const char *line)
{
	lexer_t l;
	const kon_scriptNames_t *names = p->b->names;
	long n, m;

	l.s = line;
	l.pos = 0;
	lex(&l);
	if (l.kind == T_END) return;
	if (l.kind != T_WORD) {
		problem(p, "a command is needed");
		return;
	}

	if (!is(&l, "option") && p->menu >= 0 && p->pass == 2 && p->b->cmds[p->menu].a == 0) {
		problem(p, "a menu needs options");
		return;
	}
	if (l.len > 1 && l.s[l.start + l.len - 1] == ':') {
		p->menu = -1;
		defineLabel(p, &l, l.len - 1);
		ending(p, &l);
		return;
	}
	if (is(&l, "label")) {
		lex(&l);
		p->menu = -1;
		if (l.kind != T_WORD) problem(p, "a label name is needed");
		else defineLabel(p, &l, l.len);
		ending(p, &l);
		return;
	}

	if (is(&l, "option")) {
		const char *text;
		int at, needs = -1;

		if (p->menu < 0 && p->pass == 2) {
			problem(p, "option without a menu");
			return;
		}
		lex(&l);
		if (l.kind != T_STRING) {
			problem(p, "option needs its text in quotes");
			return;
		}
		text = keep(p, &l);
		at = target(p, &l);
		lex(&l);
		if (is(&l, "if")) {
			lex(&l);
			if (!reference(&l, 's', &n)) {
				problem(p, "if needs a switch like s3");
				return;
			}
			needs = (int)n;
			lex(&l);
		}
		if (l.kind != T_END) {
			problem(p, "something extra on the line");
			return;
		}
		emit(p, KON_OP_OPTION, at, needs, 0, 0, text);
		if (p->pass == 2 && p->ok) p->b->cmds[p->menu].a++;
		return;
	}
	p->menu = -1;

	if (is(&l, "end")) {
		emit(p, KON_OP_END, 0, 0, 0, 0, NULL);
		ending(p, &l);
	} else if (is(&l, "return")) {
		emit(p, KON_OP_RETURN, 0, 0, 0, 0, NULL);
		ending(p, &l);
	} else if (is(&l, "menu")) {
		p->menu = p->b->count;
		emit(p, KON_OP_MENU, 0, 0, 0, 0, NULL);
		ending(p, &l);
	} else if (is(&l, "jump") || is(&l, "call")) {
		int op = is(&l, "jump") ? KON_OP_JUMP : KON_OP_CALL;
		int at = target(p, &l);

		emit(p, op, at, 0, 0, 0, NULL);
		ending(p, &l);
	} else if (is(&l, "wait")) {
		lex(&l);
		if (!number(&l, &n) || n < 0) {
			problem(p, "wait needs milliseconds");
			return;
		}
		emit(p, KON_OP_WAIT, (int)n, 0, 0, 0, NULL);
		ending(p, &l);
	} else if (is(&l, "on") || is(&l, "off") || is(&l, "flip")) {
		int how = is(&l, "on") ? 1 : (is(&l, "off") ? 0 : 2);

		lex(&l);
		if (!reference(&l, 's', &n)) {
			problem(p, "a switch like s3 is needed");
			return;
		}
		emit(p, KON_OP_SWITCH, (int)n, how, 0, 0, NULL);
		ending(p, &l);
	} else if (is(&l, "say")) {
		int who;
		const char *text;

		lex(&l);
		if (l.kind != T_WORD) {
			problem(p, "say needs who is talking");
			return;
		}
		who = is(&l, "-") ? -1 : nameNumber(names ? names->speakers : NULL, names ? names->speakerCount : 0, &l);
		if (who == -2) {
			problem(p, "unknown speaker");
			return;
		}
		lex(&l);
		if (l.kind != T_STRING) {
			problem(p, "say needs its text in quotes");
			return;
		}
		text = keep(p, &l);
		emit(p, KON_OP_SAY, who, 0, 0, 0, text);
		ending(p, &l);
	} else if (is(&l, "set")) {
		static const char *ops[] = {"=", "+=", "-=", "*=", "/=", "%="};
		int op = -1, i;

		lex(&l);
		if (!reference(&l, 'v', &n)) {
			problem(p, "a variable like v3 is needed");
			return;
		}
		lex(&l);
		for (i = 0; i < 6; i++) {
			if (is(&l, ops[i])) op = i;
		}
		if (op < 0) {
			problem(p, "set needs = += -= *= /= or %=");
			return;
		}
		lex(&l);
		if (reference(&l, 'v', &m)) {
			m += KON_VARIABLE;
		} else if (!number(&l, &m) || m >= KON_VARIABLE) {
			problem(p, "a number or variable is needed");
			return;
		}
		emit(p, KON_OP_VAR, (int)n, op, (int)m, 0, NULL);
		ending(p, &l);
	} else if (is(&l, "if")) {
		lex(&l);
		if (reference(&l, 's', &n)) {
			int want;
			int at;

			lex(&l);
			if (is(&l, "on")) want = 1;
			else if (is(&l, "off")) want = 0;
			else {
				problem(p, "if needs on or off");
				return;
			}
			lex(&l);
			if (!is(&l, "else")) {
				problem(p, "if needs else and a label");
				return;
			}
			at = target(p, &l);
			emit(p, KON_OP_IFSWITCH, (int)n, want, at, 0, NULL);
			ending(p, &l);
		} else if (reference(&l, 'v', &n)) {
			static const char *cmps[] = {"==", "!=", ">=", "<=", ">", "<"};
			int cmp = -1, i, at;

			lex(&l);
			for (i = 0; i < 6; i++) {
				if (is(&l, cmps[i])) cmp = i;
			}
			if (cmp < 0) {
				problem(p, "if needs == != >= <= > or <");
				return;
			}
			lex(&l);
			if (reference(&l, 'v', &m)) {
				m += KON_VARIABLE;
			} else if (!number(&l, &m) || m >= KON_VARIABLE) {
				problem(p, "a number or variable is needed");
				return;
			}
			lex(&l);
			if (!is(&l, "else")) {
				problem(p, "if needs else and a label");
				return;
			}
			at = target(p, &l);
			emit(p, KON_OP_IFVAR, (int)n, cmp, (int)m, at, NULL);
			ending(p, &l);
		} else {
			problem(p, "if needs a switch or variable");
		}
	} else if (is(&l, "host")) {
		int id, args[3] = {0, 0, 0}, i = 0;
		const char *text = NULL;

		lex(&l);
		if (l.kind != T_WORD) {
			problem(p, "host needs a name or number");
			return;
		}
		id = nameNumber(names ? names->hosts : NULL, names ? names->hostCount : 0, &l);
		if (id == -2) {
			problem(p, "unknown host command");
			return;
		}
		for (;;) {
			lex(&l);
			if (l.kind == T_STRING) {
				text = keep(p, &l);
				break;
			}
			if (l.kind != T_WORD) break;
			if (i >= 3 || !number(&l, &n)) {
				problem(p, "host takes up to three numbers then a string");
				return;
			}
			args[i++] = (int)n;
		}
		if (l.kind == T_BAD) {
			problem(p, "a string is not closed");
			return;
		}
		emit(p, KON_OP_HOST, id, args[0], args[1], args[2], text);
		if (l.kind == T_STRING) ending(p, &l);
	} else {
		problem(p, "unknown command");
	}
	if (l.kind == T_BAD) problem(p, "a string is not closed");
}

static void run(parse_t *p, const char *source)
{
	const char *s = source;
	char line[1200];

	p->line = 0;
	p->menu = -1;
	while (*s && p->ok) {
		size_t n = 0;

		p->line++;
		while (s[n] && s[n] != '\n') n++;
		if (n >= sizeof line) {
			problem(p, "line too long");
			return;
		}
		memcpy(line, s, n);
		line[n] = '\0';
		statement(p, line);
		s += n;
		if (*s == '\n') s++;
	}
	if (p->ok && p->pass == 2 && p->menu >= 0 && p->b->cmds[p->menu].a == 0) problem(p, "a menu needs options");
}

int kon_scriptParse(kon_scriptBuild_t *b, const char *source)
{
	parse_t p;

	b->count = b->labelCount = b->poolUsed = 0;
	b->errorLine = 0;
	b->error[0] = '\0';
	if (!source || !b->cmds || b->maxCmds < 0) {
		b->errorLine = 1;
		strcpy(b->error, "no source or no room");
		return 0;
	}
	p.b = b;
	p.ok = 1;
	p.pass = 1;
	run(&p, source);
	if (!p.ok) {
		b->count = 0;
		return 0;
	}
	if (b->count > b->maxCmds) {
		b->errorLine = 1;
		strcpy(b->error, "too many commands");
		b->count = 0;
		return 0;
	}
	b->count = 0;
	p.pass = 2;
	run(&p, source);
	if (!p.ok) b->count = 0;
	return p.ok;
}