raysense 0.12.0

/*
 *   Copyright (c) 2025-2026 Anton Kundenko <singaraiona@gmail.com>
 *   All rights reserved.

 *   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 "lang/eval.h"
#include "lang/env.h"
#include "lang/nfo.h"
#include <stdbool.h>
#include <string.h>

/* ── Compiler state ──
 * Internal buffers are ray_t objects whose data area holds the raw
 * bytes / pointers. This avoids calling malloc/free. */
typedef struct {
    ray_t    *code_obj;   /* RAY_U8 vector used as growable byte buffer */
    uint8_t *code;       /* == ray_data(code_obj) */
    int32_t  code_len;
    int32_t  code_cap;

    ray_t    *consts_obj; /* RAY_LIST used as growable pointer array */
    ray_t   **consts;     /* == ray_data(consts_obj) */
    int32_t  n_consts;
    int32_t  consts_cap;

    struct { int64_t sym_id; int32_t slot; } locals[256];
    int32_t  n_locals;
    int32_t  max_locals;
    bool     error;
    ray_t   *lambda;     /* the lambda being compiled (for 'self' resolution) */

    ray_t    *dbg_obj;   /* I64 vector: pairs of [offset, span.id] */
    int32_t   dbg_len;
} compiler_t;

static void compile_expr(compiler_t *c, ray_t *ast);

static bool compiler_init(compiler_t *c) {
    memset(c, 0, sizeof(*c));
    c->code_cap = 256;
    c->code_obj = ray_alloc(c->code_cap);
    if (!c->code_obj) return false;
    c->code_obj->type = RAY_U8;
    c->code_obj->len = 0;
    c->code = (uint8_t *)ray_data(c->code_obj);

    c->consts_cap = 16;
    c->consts_obj = ray_alloc(c->consts_cap * sizeof(ray_t *));
    if (!c->consts_obj) { ray_release(c->code_obj); return false; }
    c->consts_obj->type = RAY_LIST;
    c->consts_obj->len = 0;
    c->consts = (ray_t **)ray_data(c->consts_obj);
    memset(c->consts, 0, c->consts_cap * sizeof(ray_t *));
    return true;
}

static void compiler_destroy(compiler_t *c) {
    for (int32_t i = 0; i < c->n_consts; i++)
        if (c->consts[i]) ray_release(c->consts[i]);
    ray_release(c->consts_obj);
    ray_release(c->code_obj);
}

/* ── Debug info helpers ── */
static void dbg_append(compiler_t* c, int32_t offset, int64_t span_id) {
    if (!c->dbg_obj) {
        c->dbg_obj = ray_vec_new(RAY_I64, 0);
        if (!c->dbg_obj) return;
    }
    int64_t off64 = (int64_t)offset;
    c->dbg_obj = ray_vec_append(c->dbg_obj, &off64);
    c->dbg_obj = ray_vec_append(c->dbg_obj, &span_id);
}

#define EMIT_DBG(c, ast) do { \
    if ((c)->lambda && LAMBDA_NFO((c)->lambda)) { \
        ray_span_t _sp = ray_nfo_get(LAMBDA_NFO((c)->lambda), (ast)); \
        if (_sp.id != 0) dbg_append(c, (c)->code_len, _sp.id); \
    } \
} while(0)

/* ── Emit helpers ── */
static void emit(compiler_t *c, uint8_t byte) {
    if (c->code_len >= c->code_cap) {
        int32_t new_cap = c->code_cap * 2;
        ray_t *new_obj = ray_alloc(new_cap);
        if (!new_obj) { c->error = true; return; }
        new_obj->type = RAY_U8;
        new_obj->len = 0;
        memcpy(ray_data(new_obj), c->code, c->code_len);
        ray_release(c->code_obj);
        c->code_obj = new_obj;
        c->code = (uint8_t *)ray_data(new_obj);
        c->code_cap = new_cap;
    }
    c->code[c->code_len++] = byte;
}

static void emit_const(compiler_t *c, int32_t idx) {
    if (idx < 256) {
        emit(c, OP_LOADCONST);
        emit(c, (uint8_t)idx);
    } else {
        emit(c, OP_LOADCONST_W);
        emit(c, (uint8_t)(idx >> 8));
        emit(c, (uint8_t)(idx & 0xFF));
    }
}

/* ── Constant pool ── */
static int32_t add_constant(compiler_t *c, ray_t *value) {
    for (int32_t i = 0; i < c->n_consts; i++) {
        ray_t *v = c->consts[i];
        if (v == value) return i;
        if (v->type == value->type && ray_is_atom(v)) {
            if (v->type == -RAY_I64 && v->i64 == value->i64) return i;
            if (v->type == -RAY_F64 && v->f64 == value->f64) return i;
            if (v->type == -RAY_BOOL && v->b8 == value->b8) return i;
            if (v->type == -RAY_SYM && v->i64 == value->i64 &&
                v->attrs == value->attrs) return i;
        }
    }
    if (c->n_consts >= c->consts_cap) {
        int32_t new_cap = c->consts_cap * 2;
        ray_t *new_obj = ray_alloc(new_cap * sizeof(ray_t *));
        if (!new_obj || RAY_IS_ERR(new_obj)) { c->error = true; return c->n_consts; }
        new_obj->type = RAY_LIST;
        new_obj->len = 0;
        ray_t **new_arr = (ray_t **)ray_data(new_obj);
        memcpy(new_arr, c->consts, c->n_consts * sizeof(ray_t *));
        memset(new_arr + c->n_consts, 0, (new_cap - c->n_consts) * sizeof(ray_t *));
        ray_release(c->consts_obj);
        c->consts_obj = new_obj;
        c->consts = new_arr;
        c->consts_cap = new_cap;
    }
    ray_retain(value);
    c->consts[c->n_consts] = value;
    return c->n_consts++;
}

/* ── Local variable tracking ── */
static int32_t find_local(compiler_t *c, int64_t sym_id) {
    for (int32_t i = c->n_locals - 1; i >= 0; i--)
        if (c->locals[i].sym_id == sym_id) return c->locals[i].slot;
    return -1;
}

static int32_t add_local(compiler_t *c, int64_t sym_id) {
    if (c->n_locals >= 256) return -1;
    int32_t slot = c->n_locals;
    c->locals[c->n_locals].sym_id = sym_id;
    c->locals[c->n_locals].slot = slot;
    c->n_locals++;
    if (c->n_locals > c->max_locals) c->max_locals = c->n_locals;
    return slot;
}

/* ── Jump helpers ── */
static int32_t emit_jump(compiler_t *c, uint8_t opcode) {
    emit(c, opcode);
    int32_t patch_pos = c->code_len;
    emit(c, 0);
    emit(c, 0);
    return patch_pos;
}

static void patch_jump(compiler_t *c, int32_t pos) {
    int32_t raw = c->code_len - pos - 2;
    if (raw > 32767 || raw < -32768) { c->error = true; return; }
    int16_t offset = (int16_t)raw;
    c->code[pos]     = (uint8_t)(offset >> 8);
    c->code[pos + 1] = (uint8_t)(offset & 0xFF);
}

/* Cached sym IDs for special forms */
static _Thread_local int64_t sf_set = -1, sf_let = -1, sf_if = -1, sf_do = -1, sf_fn = -1, sf_self = -1, sf_try = -1;

static void init_sf_syms(void) {
    if (sf_set >= 0) return;
    sf_set  = ray_sym_intern("set", 3);
    sf_let  = ray_sym_intern("let", 3);
    sf_if   = ray_sym_intern("if",  2);
    sf_do   = ray_sym_intern("do",  2);
    sf_fn   = ray_sym_intern("fn",  2);
    sf_self = ray_sym_intern("self", 4);
    sf_try  = ray_sym_intern("try",  3);
}

/* ── Compile a list (special form or function call) ── */
static void compile_list(compiler_t *c, ray_t *ast) {
    if (c->error) return;
    EMIT_DBG(c, ast);
    int64_t n = ray_len(ast);
    if (n == 0) { c->error = true; return; }
    ray_t **elems = (ray_t **)ray_data(ast);
    ray_t *head = elems[0];

    init_sf_syms();

    /* Check for special forms by name */
    if (head->type == -RAY_SYM && (head->attrs & RAY_ATTR_NAME)) {
        int64_t sym_id = head->i64;

        /* (set name value) — dynamic eval (set modifies global env) */
        if (sym_id == sf_set && n == 3) {
            int32_t idx = add_constant(c, ast);
            emit_const(c, idx);
            emit(c, OP_CALLD);
            emit(c, 0);
            return;
        }

        /* (let name value) — compile value, store in local slot.
         * Reserved names (`.sys.*`, `.os.*`, `.csv.*`, `.ipc.*`) are
         * refused here so a compiled lambda can't shadow a builtin
         * through its local-slot table — the same guard
         * ray_env_set_local enforces on the tree-walking path.
         * Setting c->error aborts bytecode emission; call_lambda
         * then falls back to the tree-walking interpreter which
         * raises the proper `reserve` error via ray_let_fn. */
        if (sym_id == sf_let && n == 3) {
            ray_t *name_obj = elems[1];
            if (name_obj->type != -RAY_SYM ||
                ray_sym_is_reserved(name_obj->i64)) {
                c->error = true;
                return;
            }
            compile_expr(c, elems[2]);
            emit(c, OP_DUP);
            int32_t slot = find_local(c, name_obj->i64);
            if (slot < 0) slot = add_local(c, name_obj->i64);
            if (slot < 0) { c->error = true; return; }
            emit(c, OP_STOREENV);
            emit(c, (uint8_t)slot);
            return;
        }

        /* (if cond then else?) */
        if (sym_id == sf_if && n >= 3) {
            compile_expr(c, elems[1]);
            int32_t jmpf_pos = emit_jump(c, OP_JMPF);
            compile_expr(c, elems[2]);
            if (n >= 4) {
                int32_t jmp_pos = emit_jump(c, OP_JMP);
                patch_jump(c, jmpf_pos);
                compile_expr(c, elems[3]);
                patch_jump(c, jmp_pos);
            } else {
                int32_t jmp_pos = emit_jump(c, OP_JMP);
                patch_jump(c, jmpf_pos);
                ray_t *zero = ray_alloc(0);
                zero->type = -RAY_I64;
                zero->i64 = 0;
                int32_t idx = add_constant(c, zero);
                ray_release(zero);
                emit_const(c, idx);
                patch_jump(c, jmp_pos);
            }
            return;
        }

        /* (do expr1 expr2 ...) */
        if (sym_id == sf_do && n >= 2) {
            for (int64_t i = 1; i < n; i++) {
                if (i > 1) emit(c, OP_POP);
                compile_expr(c, elems[i]);
            }
            return;
        }

        /* (fn [params] body...) — nested lambda via dynamic eval */
        if (sym_id == sf_fn && n >= 3) {
            int32_t idx = add_constant(c, ast);
            emit_const(c, idx);
            emit(c, OP_CALLD);
            emit(c, 0);
            return;
        }

        /* (try body handler) — compile to OP_TRAP/OP_TRAP_END */
        if (sym_id == sf_try && n == 3) {
            /* Reserve a hidden local for err_val */
            int32_t err_slot = add_local(c, -1);
            if (err_slot < 0) { c->error = true; return; }

            int32_t trap_pos = emit_jump(c, OP_TRAP);
            compile_expr(c, elems[1]);       /* body */
            emit(c, OP_TRAP_END);
            int32_t jmp_pos = emit_jump(c, OP_JMP);
            patch_jump(c, trap_pos);         /* handler starts here */
            /* err_val is on stack (pushed by vm_error_cleanup).
             * Stash it, compile handler fn, reload err_val, call. */
            emit(c, OP_STOREENV);
            emit(c, (uint8_t)err_slot);
            compile_expr(c, elems[2]);       /* handler fn */
            emit(c, OP_LOADENV);
            emit(c, (uint8_t)err_slot);
            emit(c, OP_CALLF);
            emit(c, 1);                     /* call handler(err_val) */
            patch_jump(c, jmp_pos);          /* end */
            return;
        }
    }

    /* Self-recursive call: emit OP_CALLS (lean frame reuse, no fn object) */
    if (head->type == -RAY_SYM && (head->attrs & RAY_ATTR_NAME) &&
        head->i64 == sf_self) {
        int64_t argc = n - 1;
        if (argc > 64) { c->error = true; return; }
        for (int64_t i = 1; i < n; i++)
            compile_expr(c, elems[i]);
        emit(c, OP_CALLS);
        emit(c, (uint8_t)argc);
        return;
    }

    /* Look up head at compile time to determine call type */
    ray_t *fn = NULL;
    if (head->type == -RAY_SYM && (head->attrs & RAY_ATTR_NAME))
        fn = ray_env_get(head->i64);

    /* Unrecognized special form: dynamic eval on entire form */
    if (fn && (fn->attrs & RAY_FN_SPECIAL_FORM)) {
        int32_t idx = add_constant(c, ast);
        emit_const(c, idx);
        emit(c, OP_CALLD);
        emit(c, 0);
        return;
    }

    /* General function call: compile head, args, then dispatch.
     * If head resolved to a builtin at compile time, emit LOADCONST
     * instead of RESOLVE to skip the runtime hash lookup. */
    if (fn && (fn->type == RAY_UNARY || fn->type == RAY_BINARY || fn->type == RAY_VARY)) {
        int32_t idx = add_constant(c, fn);
        emit_const(c, idx);
    } else {
        compile_expr(c, head);
    }
    int64_t argc = n - 1;
    if (argc > 64) { c->error = true; return; }
    for (int64_t i = 1; i < n; i++)
        compile_expr(c, elems[i]);

    /* Record call-site span so errors point to the call expression, not the last arg */
    EMIT_DBG(c, ast);

    if (fn) {
        switch (fn->type) {
        case RAY_UNARY:
            if (argc == 1) { emit(c, OP_CALL1); return; }
            break;
        case RAY_BINARY:
            if (argc == 2) { emit(c, OP_CALL2); return; }
            break;
        case RAY_VARY:
            emit(c, OP_CALLN);
            emit(c, (uint8_t)argc);
            return;
        case RAY_LAMBDA:
            emit(c, OP_CALLF);
            emit(c, (uint8_t)argc);
            return;
        default:
            break;
        }
    }

    emit(c, OP_CALLF);
    emit(c, (uint8_t)argc);
}

/* ── Compile expression ── */
static void compile_expr(compiler_t *c, ray_t *ast) {
    if (c->error) return;
    if (!ast || RAY_IS_ERR(ast)) return;
    EMIT_DBG(c, ast);

    if (ray_is_atom(ast)) {
        if (ast->type == -RAY_SYM && (ast->attrs & RAY_ATTR_NAME)) {
            int32_t slot = find_local(c, ast->i64);
            if (slot >= 0) {
                emit(c, OP_LOADENV);
                emit(c, (uint8_t)slot);
            } else {
                int32_t idx = add_constant(c, ast);
                if (idx < 256) {
                    emit(c, OP_RESOLVE);
                    emit(c, (uint8_t)idx);
                } else {
                    emit(c, OP_RESOLVE_W);
                    emit(c, (uint8_t)(idx >> 8));
                    emit(c, (uint8_t)(idx & 0xFF));
                }
            }
            return;
        }
        int32_t idx = add_constant(c, ast);
        emit_const(c, idx);
        return;
    }

    if (ast->type != RAY_LIST) {
        int32_t idx = add_constant(c, ast);
        emit_const(c, idx);
        return;
    }

    if (ray_len(ast) == 0) {
        int32_t idx = add_constant(c, ast);
        emit_const(c, idx);
        return;
    }

    compile_list(c, ast);
}

/* ── Public API ── */
void ray_compile(ray_t *lambda) {
    if (LAMBDA_IS_COMPILED(lambda)) return;

    compiler_t c;
    if (!compiler_init(&c)) return;
    c.lambda = lambda;

    /* Register params as locals */
    ray_t *params_list = LAMBDA_PARAMS(lambda);
    int64_t param_count = ray_len(params_list);
    int64_t *param_ids = (int64_t*)ray_data(params_list);
    for (int64_t i = 0; i < param_count; i++) {
        if (add_local(&c, param_ids[i]) < 0) { c.error = true; break; }
    }

    /* Compile body expressions */
    ray_t *body = LAMBDA_BODY(lambda);
    int64_t body_count = ray_len(body);
    ray_t **body_exprs = (ray_t **)ray_data(body);
    for (int64_t i = 0; i < body_count; i++) {
        if (i > 0) emit(&c, OP_POP);
        compile_expr(&c, body_exprs[i]);
    }
    emit(&c, OP_RET);

    if (c.error) {
        if (c.dbg_obj) ray_release(c.dbg_obj);
        compiler_destroy(&c);
        return;
    }

    /* Build bytecode vector */
    ray_t *bc = ray_alloc(c.code_len);
    if (!bc) { compiler_destroy(&c); return; }
    bc->type = RAY_U8;
    bc->len = c.code_len;
    memcpy(ray_data(bc), c.code, c.code_len);

    /* Build constants list */
    ray_t *consts = ray_alloc(c.n_consts * sizeof(ray_t *));
    if (!consts) { ray_release(bc); compiler_destroy(&c); return; }
    consts->type = RAY_LIST;
    consts->len = c.n_consts;
    ray_t **cpool = (ray_t **)ray_data(consts);
    for (int32_t i = 0; i < c.n_consts; i++) {
        ray_retain(c.consts[i]);
        cpool[i] = c.consts[i];
    }

    LAMBDA_BC(lambda) = bc;
    LAMBDA_CONSTS(lambda) = consts;
    LAMBDA_NLOCALS(lambda) = c.max_locals;
    lambda->attrs |= RAY_FN_COMPILED;

    if (c.dbg_obj) {
        LAMBDA_DBG(lambda) = c.dbg_obj;
        /* dbg_obj is now owned by the lambda, don't release it */
    }

    compiler_destroy(&c);
}

ray_span_t ray_bc_dbg_get(ray_t* dbg, int32_t ip) {
    ray_span_t span = {0};
    if (!dbg || dbg->len == 0) return span;
    int64_t* data = (int64_t*)ray_data(dbg);
    int64_t n = dbg->len;
    int64_t best_offset = -1;
    for (int64_t i = 0; i < n; i += 2) {
        int64_t offset = data[i];
        if (offset <= ip && offset > best_offset) {
            best_offset = offset;
            span.id = data[i + 1];
        }
    }
    return span;
}

void ray_compile_reset(void) {
    sf_set = sf_let = sf_if = sf_do = sf_fn = sf_self = sf_try = -1;
}