#include "aup.h"
#include <math.h>
#include <setjmp.h>
#include <stdarg.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

/* Limits and opcodes of Pure module format v1. */
enum { STATES = 32, INPUTS = 8, VIEWS = 24, HANDLERS = 64, CODE = 512, STACK = 64, NAME = 32, DEPTH = 64 };
enum { CONST, LOAD, DT, ADD, SUB, MUL, DIV, NEG, LT, LE, GT, GE, EQ, NE, AND, OR, NOT,
       MIN, MAX, CLAMP, STORE, JZ, JMP };

typedef enum { T_EOF, T_NL, T_NUMBER, T_NAME, T_PUNCT } TokenKind;
typedef struct {
    TokenKind kind;
    int line, column;
    double number;
    char text[NAME + 1]; /* name, or punctuation of one or two characters */
} Token;

typedef enum { E_NUMBER, E_STATE, E_DT, E_UNARY, E_BINARY, E_CALL } ExprKind;
typedef struct Expr {
    ExprKind kind;
    int line, column, op, state;
    double number;
    char name[NAME];
    struct Expr *args[3];
    unsigned count;
} Expr;

typedef struct Stmt {
    bool branch;
    int line, column, state;
    char name[NAME];
    Expr *value;          /* assignment value or branch condition */
    struct Stmt *then, *otherwise, *next;
} Stmt;

typedef struct {
    const char *source;
    size_t length, at;
    int line, column;
    Token token, ahead;
    bool has_ahead;
    unsigned depth;
    jmp_buf fail;
    AupDiagnostic *error;
    void **blocks;
    size_t block_count, block_capacity;
    /* Declarations in source order. */
    char state_names[STATES][NAME];
    double initial[STATES];
    unsigned states;
    char input_names[INPUTS][NAME], input_keys[INPUTS][NAME];
    unsigned inputs;
    char view_names[VIEWS][NAME];
    Expr *view_value[VIEWS];
    unsigned views;
    struct { char input[NAME]; int edge, line, column; Stmt *body; } handlers[HANDLERS];
    unsigned handler_count;
    /* Code generation. */
    struct { uint8_t op; uint32_t arg; double value; } code[CODE];
    unsigned code_count;
    uint32_t view_code[VIEWS][2], handler_code[HANDLERS][2];
} Compiler;

static const char *const reserved[] = {"state", "input", "view", "on", "if", "else", "key",
                                       "frame", "dt", "min", "max", "clamp"};

static _Noreturn void fail_at(Compiler *c, int line, int column, const char *format, ...) {
    va_list args;
    va_start(args, format);
    c->error->line = line;
    c->error->column = column;
    vsnprintf(c->error->message, sizeof(c->error->message), format, args);
    va_end(args);
    longjmp(c->fail, 1);
}

static void *allocate(Compiler *c, size_t size) {
    if (c->block_count == c->block_capacity) {
        size_t capacity = c->block_capacity ? 2 * c->block_capacity : 64;
        void **blocks = realloc(c->blocks, capacity * sizeof(*blocks));
        if (!blocks) fail_at(c, c->line, c->column, "out of memory");
        c->blocks = blocks;
        c->block_capacity = capacity;
    }
    void *block = calloc(1, size);
    if (!block) fail_at(c, c->line, c->column, "out of memory");
    return c->blocks[c->block_count++] = block;
}

/* ---- Lexer ---------------------------------------------------------- */

static char peek_char(const Compiler *c, size_t offset) {
    return c->at + offset < c->length ? c->source[c->at + offset] : 0;
}

static void advance(Compiler *c) {
    if (c->source[c->at++] == '\n') { ++c->line; c->column = 1; } else ++c->column;
}

static bool digit(char ch) { return ch >= '0' && ch <= '9'; }
static bool letter(char ch) { return (ch >= 'a' && ch <= 'z') || (ch >= 'A' && ch <= 'Z') || ch == '_'; }

static Token scan(Compiler *c) {
    for (;;) {
        char ch = peek_char(c, 0);
        if (ch == ' ' || ch == '\t' || ch == '\r') advance(c);
        else if (ch == '#') while (c->at < c->length && peek_char(c, 0) != '\n') advance(c);
        else break;
    }
    Token token = {.line = c->line, .column = c->column};
    if (c->at >= c->length) { token.kind = T_EOF; return token; }
    char ch = peek_char(c, 0);
    if (ch == '\n') { advance(c); token.kind = T_NL; return token; }
    if (digit(ch) || (ch == '.' && digit(peek_char(c, 1)))) {
        /* \d+(\.\d*)?|\.\d+ with an optional exponent, as the workbench reads it. */
        char text[400];
        size_t n = 0;
        while (digit(peek_char(c, 0)) || peek_char(c, 0) == '.') {
            if (peek_char(c, 0) == '.' && memchr(text, '.', n)) break;
            if (n + 1 >= sizeof(text)) fail_at(c, token.line, token.column, "number is too long");
            text[n++] = peek_char(c, 0);
            advance(c);
        }
        char e = peek_char(c, 0);
        size_t sign = peek_char(c, 1) == '+' || peek_char(c, 1) == '-';
        if ((e == 'e' || e == 'E') && digit(peek_char(c, 1 + sign))) {
            for (size_t i = 0; i < 1 + sign; ++i) { text[n++] = peek_char(c, 0); advance(c); }
            while (digit(peek_char(c, 0))) {
                if (n + 1 >= sizeof(text)) fail_at(c, token.line, token.column, "number is too long");
                text[n++] = peek_char(c, 0);
                advance(c);
            }
        }
        text[n] = 0;
        token.kind = T_NUMBER;
        token.number = strtod(text, NULL);
        if (!isfinite(token.number)) fail_at(c, token.line, token.column, "number must be finite");
        return token;
    }
    if (letter(ch)) {
        size_t n = 0;
        while (letter(peek_char(c, 0)) || digit(peek_char(c, 0))) {
            if (n + 1 >= NAME) fail_at(c, token.line, token.column, "name exceeds 31 bytes");
            token.text[n++] = peek_char(c, 0);
            advance(c);
        }
        token.kind = T_NAME;
        return token;
    }
    static const char *const pairs[] = {"<=", ">=", "==", "!=", "&&", "||"};
    for (size_t i = 0; i < sizeof(pairs) / sizeof(*pairs); ++i)
        if (ch == pairs[i][0] && peek_char(c, 1) == pairs[i][1]) {
            memcpy(token.text, pairs[i], 3);
            advance(c);
            advance(c);
            token.kind = T_PUNCT;
            return token;
        }
    if (strchr("=+-*/!<>(){},.;", ch)) {
        token.text[0] = ch;
        advance(c);
        token.kind = T_PUNCT;
        return token;
    }
    if ((unsigned char)ch >= 32 && (unsigned char)ch < 127)
        fail_at(c, token.line, token.column, "unexpected character '%c'", ch);
    fail_at(c, token.line, token.column, "unexpected byte 0x%02x", (unsigned char)ch);
}

static Token take(Compiler *c) {
    Token token = c->token;
    if (c->has_ahead) { c->token = c->ahead; c->has_ahead = false; }
    else c->token = scan(c);
    return token;
}

static const Token *lookahead(Compiler *c) {
    if (!c->has_ahead) { c->ahead = scan(c); c->has_ahead = true; }
    return &c->ahead;
}

static bool is(const Compiler *c, const char *punct) {
    return c->token.kind == T_PUNCT && !strcmp(c->token.text, punct);
}

static bool word(const Compiler *c, const char *name) {
    return c->token.kind == T_NAME && !strcmp(c->token.text, name);
}

static Token expect(Compiler *c, const char *punct, const char *what) {
    if (!is(c, punct)) fail_at(c, c->token.line, c->token.column, "expected %s", what);
    return take(c);
}

static Token expect_name(Compiler *c, const char *what) {
    if (c->token.kind != T_NAME) fail_at(c, c->token.line, c->token.column, "expected %s", what);
    return take(c);
}

static void newlines(Compiler *c) { while (c->token.kind == T_NL) take(c); }
static void separators(Compiler *c) { while (c->token.kind == T_NL || is(c, ";")) take(c); }

static void end(Compiler *c) {
    if (c->token.kind != T_NL && c->token.kind != T_EOF && !is(c, ";") && !is(c, "}"))
        fail_at(c, c->token.line, c->token.column, "expected newline or semicolon");
    separators(c);
}

static bool reserved_name(const char *name) {
    for (size_t i = 0; i < sizeof(reserved) / sizeof(*reserved); ++i)
        if (!strcmp(name, reserved[i])) return true;
    return false;
}

/* ---- Parser --------------------------------------------------------- */

static const struct { const char *text; int precedence, op; } binary[] = {
    {"||", 1, OR}, {"&&", 2, AND}, {"==", 3, EQ}, {"!=", 3, NE}, {"<", 4, LT}, {"<=", 4, LE},
    {">", 4, GT}, {">=", 4, GE}, {"+", 5, ADD}, {"-", 5, SUB}, {"*", 6, MUL}, {"/", 6, DIV},
};

static Expr *node(Compiler *c, ExprKind kind, const Token *at) {
    Expr *e = allocate(c, sizeof(*e));
    e->kind = kind;
    e->line = at->line;
    e->column = at->column;
    return e;
}

static Expr *expression(Compiler *c, int minimum, bool multiline) {
    if (++c->depth > DEPTH) fail_at(c, c->token.line, c->token.column, "expression nesting exceeds 64");
    if (multiline) newlines(c);
    Token token = take(c);
    Expr *left;
    if (token.kind == T_NUMBER) {
        left = node(c, E_NUMBER, &token);
        left->number = token.number;
    } else if (token.kind == T_PUNCT && (!strcmp(token.text, "-") || !strcmp(token.text, "!"))) {
        left = node(c, E_UNARY, &token);
        left->op = token.text[0] == '-' ? NEG : NOT;
        left->args[0] = expression(c, 7, multiline);
        left->count = 1;
    } else if (token.kind == T_PUNCT && !strcmp(token.text, "(")) {
        left = expression(c, 0, true);
        newlines(c);
        expect(c, ")", "')'");
    } else if (token.kind == T_NAME) {
        static const struct { const char *name; unsigned count; int op; } calls[] =
            {{"min", 2, MIN}, {"max", 2, MAX}, {"clamp", 3, CLAMP}};
        int call = -1;
        for (int i = 0; i < 3; ++i) if (!strcmp(token.text, calls[i].name)) call = i;
        if (call >= 0 && is(c, "(")) {
            take(c);
            left = node(c, E_CALL, &token);
            left->op = calls[call].op;
            newlines(c);
            while (!is(c, ")")) {
                if (left->count == 3) fail_at(c, token.line, token.column, "%s expects %u arguments", token.text, calls[call].count);
                left->args[left->count++] = expression(c, 0, true);
                newlines(c);
                if (!is(c, ",")) break;
                take(c);
                newlines(c);
            }
            expect(c, ")", "')'");
            if (left->count != calls[call].count)
                fail_at(c, token.line, token.column, "%s expects %u arguments", token.text, calls[call].count);
        } else if (!strcmp(token.text, "dt")) {
            left = node(c, E_DT, &token);
        } else {
            if (reserved_name(token.text)) fail_at(c, token.line, token.column, "expected a number, state, or expression");
            left = node(c, E_STATE, &token);
            memcpy(left->name, token.text, NAME);
        }
    } else fail_at(c, token.line, token.column, "expected a number, state, or expression");
    for (;;) {
        if (multiline) newlines(c);
        int found = -1;
        if (c->token.kind == T_PUNCT)
            for (int i = 0; i < 12; ++i) if (!strcmp(c->token.text, binary[i].text)) found = i;
        if (found < 0 || binary[found].precedence < minimum) break;
        Token op = take(c);
        Expr *e = node(c, E_BINARY, &op);
        e->op = binary[found].op;
        e->args[0] = left;
        e->args[1] = expression(c, binary[found].precedence + 1, multiline);
        e->count = 2;
        left = e;
    }
    --c->depth;
    return left;
}

static Stmt *block(Compiler *c, unsigned depth);

static Stmt *statement(Compiler *c, unsigned depth) {
    Token token = expect_name(c, "assignment, if, or '}'");
    Stmt *s = allocate(c, sizeof(*s));
    s->line = token.line;
    s->column = token.column;
    if (!strcmp(token.text, "if")) {
        s->branch = true;
        s->value = expression(c, 0, false);
        s->then = block(c, depth + 1);
        /* else may follow on the same line or after newlines */
        bool has_else = word(c, "else");
        if (!has_else && c->token.kind == T_NL) {
            const Token *next = lookahead(c);
            if (next->kind == T_NAME && !strcmp(next->text, "else")) { take(c); has_else = true; }
        }
        if (has_else) {
            take(c);
            if (word(c, "if")) s->otherwise = statement(c, depth + 1);
            else s->otherwise = block(c, depth + 1);
        }
        return s;
    }
    if (reserved_name(token.text)) fail_at(c, token.line, token.column, "expected assignment, if, or '}'");
    memcpy(s->name, token.text, NAME);
    expect(c, "=", "'='");
    s->value = expression(c, 0, false);
    return s;
}

static Stmt *block(Compiler *c, unsigned depth) {
    if (depth >= DEPTH) fail_at(c, c->token.line, c->token.column, "block nesting exceeds 64");
    newlines(c);
    expect(c, "{", "'{'");
    separators(c);
    Stmt *first = NULL, **tail = &first;
    while (!is(c, "}")) {
        if (c->token.kind == T_EOF) fail_at(c, c->token.line, c->token.column, "expected '}'");
        *tail = statement(c, depth);
        tail = &(*tail)->next;
        end(c);
    }
    take(c);
    return first;
}

static const char *declared_kind(const Compiler *c, const char *name) {
    for (unsigned i = 0; i < c->states; ++i) if (!strcmp(c->state_names[i], name)) return "state";
    for (unsigned i = 0; i < c->inputs; ++i) if (!strcmp(c->input_names[i], name)) return "input";
    for (unsigned i = 0; i < c->views; ++i) if (!strcmp(c->view_names[i], name)) return "view";
    return NULL;
}

static void declare(Compiler *c, const Token *name) {
    if (reserved_name(name->text)) fail_at(c, name->line, name->column, "'%s' is reserved", name->text);
    const char *kind = declared_kind(c, name->text);
    if (kind) fail_at(c, name->line, name->column, "'%s' is already declared as a %s", name->text, kind);
}

static bool key_name(const char *key) {
    static const char *const named[] = {"Space", "Enter", "ArrowLeft", "ArrowRight", "ArrowUp", "ArrowDown"};
    for (size_t i = 0; i < sizeof(named) / sizeof(*named); ++i) if (!strcmp(key, named[i])) return true;
    if (!strncmp(key, "Key", 3)) return key[3] >= 'A' && key[3] <= 'Z' && !key[4];
    if (!strncmp(key, "Digit", 5)) return key[5] >= '0' && key[5] <= '9' && !key[6];
    return false;
}

static void declaration(Compiler *c) {
    Token kind = expect_name(c, "state, input, view, or on");
    if (!strcmp(kind.text, "state")) {
        Token name = expect_name(c, "state name");
        declare(c, &name);
        if (c->states == STATES) fail_at(c, name.line, name.column, "at most 32 states are allowed");
        expect(c, "=", "'='");
        double sign = 1;
        if (is(c, "-") || is(c, "+")) sign = take(c).text[0] == '-' ? -1 : 1;
        if (c->token.kind != T_NUMBER) fail_at(c, c->token.line, c->token.column, "expected a numeric state initializer");
        memcpy(c->state_names[c->states], name.text, NAME);
        c->initial[c->states++] = sign * take(c).number;
    } else if (!strcmp(kind.text, "input")) {
        Token name = expect_name(c, "input name");
        declare(c, &name);
        if (c->inputs == INPUTS) fail_at(c, name.line, name.column, "at most 8 inputs are allowed");
        expect(c, "=", "'='");
        if (!word(c, "key")) fail_at(c, c->token.line, c->token.column, "expected 'key'");
        take(c);
        Token key = expect_name(c, "key name");
        if (!key_name(key.text)) fail_at(c, key.line, key.column, "unknown key '%s'", key.text);
        for (unsigned i = 0; i < c->inputs; ++i)
            if (!strcmp(c->input_keys[i], key.text))
                fail_at(c, key.line, key.column, "key %s is already used by input '%s'", key.text, c->input_names[i]);
        memcpy(c->input_names[c->inputs], name.text, NAME);
        memcpy(c->input_keys[c->inputs++], key.text, NAME);
    } else if (!strcmp(kind.text, "view")) {
        Token name = expect_name(c, "view name");
        declare(c, &name);
        if (c->views == VIEWS) fail_at(c, name.line, name.column, "at most 24 views are allowed");
        expect(c, "=", "'='");
        memcpy(c->view_names[c->views], name.text, NAME);
        c->view_value[c->views++] = expression(c, 0, false);
    } else if (!strcmp(kind.text, "on")) {
        if (c->handler_count == HANDLERS) fail_at(c, kind.line, kind.column, "at most 64 handlers are allowed");
        Token event = expect_name(c, "frame or an input event");
        unsigned index = c->handler_count++;
        c->handlers[index].line = event.line;
        c->handlers[index].column = event.column;
        if (strcmp(event.text, "frame")) {
            /* The input may be declared later; it is resolved at generation. */
            expect(c, ".", "'.' and down or up");
            Token phase = expect_name(c, "down or up");
            if (strcmp(phase.text, "down") && strcmp(phase.text, "up"))
                fail_at(c, phase.line, phase.column, "expected down or up");
            memcpy(c->handlers[index].input, event.text, NAME);
            c->handlers[index].edge = phase.text[0] == 'u';
        }
        c->handlers[index].body = block(c, 0);
    } else fail_at(c, kind.line, kind.column, "unknown declaration '%s'", kind.text);
    end(c);
}

/* ---- Checks and code generation ------------------------------------- */

static void emit(Compiler *c, int line, int column, uint8_t op, uint32_t arg, double value) {
    if (c->code_count == CODE) fail_at(c, line, column, "program exceeds 512 instructions");
    c->code[c->code_count].op = op;
    c->code[c->code_count].arg = arg;
    c->code[c->code_count++].value = value;
}

static int state_index(const Compiler *c, const char *name) {
    for (unsigned i = 0; i < c->states; ++i) if (!strcmp(c->state_names[i], name)) return (int)i;
    return -1;
}

/* Emit an expression; height is the stack height before it. */
static void value(Compiler *c, const Expr *e, bool handler, int height) {
    if (height + 1 > STACK) fail_at(c, e->line, e->column, "expression needs more than 64 stack values");
    switch (e->kind) {
    case E_NUMBER: emit(c, e->line, e->column, CONST, 0, e->number); return;
    case E_DT:
        if (!handler) fail_at(c, e->line, e->column, "dt is only available in handlers");
        emit(c, e->line, e->column, DT, 0, 0);
        return;
    case E_STATE: {
        int index = state_index(c, e->name);
        if (index < 0) {
            const char *kind = declared_kind(c, e->name);
            if (kind) fail_at(c, e->line, e->column, "'%s' is a %s, not a state", e->name, kind);
            fail_at(c, e->line, e->column, "unknown state '%s'", e->name);
        }
        emit(c, e->line, e->column, LOAD, (uint32_t)index, 0);
        return;
    }
    default:
        for (unsigned i = 0; i < e->count; ++i) value(c, e->args[i], handler, height + (int)i);
        emit(c, e->line, e->column, (uint8_t)e->op, 0, 0);
    }
}

static void statements(Compiler *c, const Stmt *s) {
    for (; s; s = s->next) {
        if (!s->branch) {
            int index = state_index(c, s->name);
            if (index < 0) {
                const char *kind = declared_kind(c, s->name);
                if (kind) fail_at(c, s->line, s->column, "cannot assign to %s '%s'", kind, s->name);
                fail_at(c, s->line, s->column, "unknown state '%s'", s->name);
            }
            value(c, s->value, true, 0);
            emit(c, s->line, s->column, STORE, (uint32_t)index, 0);
            continue;
        }
        value(c, s->value, true, 0);
        unsigned jump = c->code_count;
        emit(c, s->line, s->column, JZ, 0, 0);
        statements(c, s->then);
        if (s->otherwise) {
            unsigned skip = c->code_count;
            emit(c, s->line, s->column, JMP, 0, 0);
            c->code[jump].arg = c->code_count;
            statements(c, s->otherwise);
            c->code[skip].arg = c->code_count;
        } else c->code[jump].arg = c->code_count;
    }
}

static unsigned char *put32(unsigned char *p, uint32_t v) {
    for (unsigned i = 0; i < 4; ++i) p[i] = (unsigned char)(v >> (8 * i));
    return p + 4;
}

static unsigned char *put_double(unsigned char *p, double value) {
    uint64_t bits;
    memcpy(&bits, &value, sizeof(bits));
    put32(p, (uint32_t)bits);
    return put32(p + 4, (uint32_t)(bits >> 32));
}

/* Deduplicated [u8 length][bytes] strings; returns the offset. */
static uint32_t intern(unsigned char *strings, size_t *used, const char *text) {
    size_t length = strlen(text);
    for (size_t at = 0; at < *used; at += 1u + strings[at])
        if (strings[at] == length && !memcmp(strings + at + 1, text, length)) return (uint32_t)at;
    uint32_t offset = (uint32_t)*used;
    strings[(*used)++] = (unsigned char)length;
    memcpy(strings + *used, text, length);
    *used += length;
    return offset;
}

static void generate(Compiler *c, unsigned char **module, size_t *size) {
    uint32_t events[HANDLERS];
    for (unsigned i = 0; i < c->handler_count; ++i) {
        const char *name = c->handlers[i].input;
        events[i] = 0; /* frame */
        if (!*name) continue;
        int input = -1;
        for (unsigned k = 0; k < c->inputs; ++k) if (!strcmp(c->input_names[k], name)) input = (int)k;
        if (input < 0) {
            const char *kind = declared_kind(c, name);
            if (kind) fail_at(c, c->handlers[i].line, c->handlers[i].column, "'%s' is a %s, not an input", name, kind);
            fail_at(c, c->handlers[i].line, c->handlers[i].column, "unknown input '%s'", name);
        }
        events[i] = 1u + 2u * (uint32_t)input + (uint32_t)c->handlers[i].edge;
    }
    /* Views, then handlers, each as one contiguous block. */
    for (unsigned i = 0; i < c->views; ++i) {
        c->view_code[i][0] = c->code_count;
        value(c, c->view_value[i], false, 0);
        c->view_code[i][1] = c->code_count - c->view_code[i][0];
    }
    for (unsigned i = 0; i < c->handler_count; ++i) {
        c->handler_code[i][0] = c->code_count;
        statements(c, c->handlers[i].body);
        c->handler_code[i][1] = c->code_count - c->handler_code[i][0];
    }
    static unsigned char strings[STATES * NAME + 2 * INPUTS * NAME + VIEWS * NAME];
    size_t used = 0;
    uint32_t state_name[STATES], input_name[INPUTS], input_key[INPUTS], view_name[VIEWS];
    for (unsigned i = 0; i < c->states; ++i) state_name[i] = intern(strings, &used, c->state_names[i]);
    for (unsigned i = 0; i < c->inputs; ++i) {
        input_name[i] = intern(strings, &used, c->input_names[i]);
        input_key[i] = intern(strings, &used, c->input_keys[i]);
    }
    for (unsigned i = 0; i < c->views; ++i) view_name[i] = intern(strings, &used, c->view_names[i]);
    *size = 32 + 16u * c->states + 12u * (c->inputs + c->views + c->handler_count) + 16u * c->code_count + used;
    unsigned char *p = *module = allocate(c, *size);
    memcpy(p, "PUREMOD1", 8);
    p[8] = (unsigned char)c->states; p[10] = (unsigned char)c->inputs;
    p[12] = (unsigned char)c->views; p[14] = (unsigned char)c->handler_count;
    put32(p + 16, c->code_count);
    put32(p + 20, (uint32_t)used);
    p += 32;
    for (unsigned i = 0; i < c->states; ++i) { p = put32(p, state_name[i]); p = put32(p, 0); p = put_double(p, c->initial[i]); }
    for (unsigned i = 0; i < c->inputs; ++i) { p = put32(p, input_name[i]); p = put32(p, 1); p = put32(p, input_key[i]); }
    for (unsigned i = 0; i < c->views; ++i) { p = put32(p, view_name[i]); p = put32(p, c->view_code[i][0]); p = put32(p, c->view_code[i][1]); }
    for (unsigned i = 0; i < c->handler_count; ++i) {
        p = put32(p, events[i]);
        p = put32(p, c->handler_code[i][0]);
        p = put32(p, c->handler_code[i][1]);
    }
    for (unsigned i = 0; i < c->code_count; ++i) {
        *p++ = c->code[i].op; *p++ = 0; *p++ = 0; *p++ = 0;
        p = put32(p, c->code[i].arg);
        p = put_double(p, c->code[i].value);
    }
    memcpy(p, strings, used);
}

bool aup_compile(const char *source, size_t length, unsigned char **module, size_t *size,
                 AupDiagnostic *error) {
    *module = NULL;
    *size = 0;
    *error = (AupDiagnostic){0};
    Compiler *c = calloc(1, sizeof(*c));
    if (!c) { *error = (AupDiagnostic){1, 1, "out of memory"}; return false; }
    c->source = source;
    c->length = length;
    c->line = c->column = 1;
    c->error = error;
    unsigned char *result = NULL;
    if (!setjmp(c->fail)) {
        if (length > AUP_SOURCE_LIMIT) fail_at(c, 1, 1, "source exceeds 32768 bytes");
        c->token = scan(c);
        separators(c);
        while (c->token.kind != T_EOF) declaration(c);
        generate(c, &result, size);
        *module = malloc(*size);
        if (!*module) fail_at(c, 1, 1, "out of memory");
        memcpy(*module, result, *size);
    } else {
        free(*module);
        *module = NULL;
        *size = 0;
    }
    for (size_t i = 0; i < c->block_count; ++i) free(c->blocks[i]);
    free(c->blocks);
    free(c);
    return *module != NULL;
}