"""
Box-related operations for the Nyash PyVM: newbox and boxcall.
Kept behaviorally identical to the original vm.py code.
"""
from __future__ import annotations

from typing import Any, Dict, List
import os


def op_newbox(owner, inst: Dict[str, Any], regs: Dict[int, Any]) -> None:
    btype = inst.get("type")
    # Sandbox gate: only allow minimal boxes when sandbox is active
    if not owner._sandbox_allow_newbox(str(btype)):
        val = {"__box__": str(btype), "__denied__": True}
    elif btype == "ConsoleBox":
        val = {"__box__": "ConsoleBox"}
    elif btype == "StringBox":
        # empty string instance
        val = ""
    elif btype == "ArrayBox":
        val = {"__box__": "ArrayBox", "__arr": []}
    elif btype == "MapBox":
        val = {"__box__": "MapBox", "__map": {}}
    else:
        # Unknown box -> opaque
        val = {"__box__": btype}
    owner._set(regs, inst.get("dst"), val)


def op_boxcall(owner, fn, inst: Dict[str, Any], regs: Dict[int, Any]) -> None:
    recv = owner._read(regs, inst.get("box"))
    method = inst.get("method")
    args: List[Any] = [owner._read(regs, a) for a in inst.get("args", [])]
    out: Any = None
    owner._dbg(f"[pyvm] boxcall recv={recv} method={method} args={args}")

    # Sandbox gate: disallow unsafe/unknown boxcalls
    if not owner._sandbox_allow_boxcall(recv, method):
        owner._set(regs, inst.get("dst"), out)
        return

    # Special-case: inside a method body, 'me.method(...)' lowers to a
    # boxcall with a synthetic receiver marker '__me__'. Resolve it by
    # dispatching to the current box's lowered function if available.
    if isinstance(recv, str) and recv == "__me__" and isinstance(method, str):
        box_name = ""
        try:
            if "." in fn.name:
                box_name = fn.name.split(".")[0]
        except Exception:
            box_name = ""
        if box_name:
            cand = f"{box_name}.{method}/{len(args)}"
            callee = owner.functions.get(cand)
            if callee is not None:
                owner._dbg(f"[pyvm] boxcall(__me__) -> {cand} args={args}")
                out = owner._exec_function(callee, args)
                owner._set(regs, inst.get("dst"), out)
                return

    # User-defined box: dispatch to lowered function if available (Box.method/N)
    if isinstance(recv, dict) and isinstance(method, str) and "__box__" in recv:
        box_name = recv.get("__box__")
        cand = f"{box_name}.{method}/{len(args)}"
        callee = owner.functions.get(cand)
        if callee is not None:
            owner._dbg(f"[pyvm] boxcall dispatch -> {cand} args={args}")
            out = owner._exec_function(callee, args)
            owner._set(regs, inst.get("dst"), out)
            return
        else:
            if owner._debug:
                prefix = f"{box_name}.{method}/"
                cands = sorted([k for k in owner.functions.keys() if k.startswith(prefix)])
                if cands:
                    owner._dbg(f"[pyvm] boxcall unresolved: '{cand}' — available: {cands}")
                else:
                    any_for_box = sorted([k for k in owner.functions.keys() if k.startswith(f"{box_name}.")])
                    owner._dbg(f"[pyvm] boxcall unresolved: '{cand}' — no candidates; methods for {box_name}: {any_for_box}")

    # ConsoleBox methods
    if method in ("print", "println", "log") and owner._is_console(recv):
        s = args[0] if args else ""
        if s is None:
            s = ""
        # println is the primary one used by smokes; keep print/log equivalent
        print(str(s))
        out = 0

    # FileBox methods (minimal read-only)
    elif isinstance(recv, dict) and recv.get("__box__") == "FileBox":
        if method == "open":
            path = str(args[0]) if len(args) > 0 else ""
            mode = str(args[1]) if len(args) > 1 else "r"
            ok = 0
            content = None
            if mode == "r":
                try:
                    with open(path, "r", encoding="utf-8") as f:
                        content = f.read()
                    ok = 1
                except Exception:
                    ok = 0
                    content = None
            recv["__open"] = (ok == 1)
            recv["__path"] = path
            recv["__content"] = content
            out = ok
        elif method == "read":
            if isinstance(recv.get("__content"), str):
                out = recv.get("__content")
            else:
                out = None
        elif method == "close":
            recv["__open"] = False
            out = 0
        else:
            out = None

    # PathBox methods (posix-like)
    elif isinstance(recv, dict) and recv.get("__box__") == "PathBox":
        if method == "dirname":
            p = str(args[0]) if args else ""
            out = os.path.dirname(p)
            if out == "":
                out = "."
        elif method == "join":
            base = str(args[0]) if len(args) > 0 else ""
            rel = str(args[1]) if len(args) > 1 else ""
            out = os.path.join(base, rel)
        else:
            out = None

    # ArrayBox minimal methods
    elif isinstance(recv, dict) and recv.get("__box__") == "ArrayBox":
        arr = recv.get("__arr", [])
        if method in ("len", "size"):
            out = len(arr)
        elif method == "get":
            idx = int(args[0]) if args else 0
            out = arr[idx] if 0 <= idx < len(arr) else None
        elif method == "set":
            idx = int(args[0]) if len(args) > 0 else 0
            val = args[1] if len(args) > 1 else None
            if 0 <= idx < len(arr):
                arr[idx] = val
            elif idx == len(arr):
                arr.append(val)
            else:
                while len(arr) < idx:
                    arr.append(None)
                arr.append(val)
            out = 0
        elif method == "push":
            val = args[0] if args else None
            arr.append(val)
            out = len(arr)
        elif method == "toString":
            out = "[" + ",".join(str(x) for x in arr) + "]"
        else:
            out = None
        recv["__arr"] = arr

    # MapBox minimal methods
    elif isinstance(recv, dict) and recv.get("__box__") == "MapBox":
        m = recv.get("__map", {})
        if method == "size":
            out = len(m)
        elif method == "has":
            key = str(args[0]) if args else ""
            out = 1 if key in m else 0
        elif method == "get":
            key = str(args[0]) if args else ""
            out = m.get(key)
        elif method == "set":
            key = str(args[0]) if len(args) > 0 else ""
            val = args[1] if len(args) > 1 else None
            m[key] = val
            out = 0
        elif method == "toString":
            items = ",".join(f"{k}:{m[k]}" for k in m)
            out = "{" + items + "}"
        else:
            out = None
        recv["__map"] = m

    elif method == "esc_json":
        s = args[0] if args else ""
        s = "" if s is None else str(s)
        out_chars: List[str] = []
        for ch in s:
            if ch == "\\":
                out_chars.append("\\\\")
            elif ch == '"':
                out_chars.append('\\"')
            else:
                out_chars.append(ch)
        out = "".join(out_chars)

    elif method == "length":
        out = len(str(recv))

    elif method == "substring":
        s = str(recv)
        start = int(args[0]) if (len(args) > 0 and args[0] is not None) else 0
        end = int(args[1]) if (len(args) > 1 and args[1] is not None) else len(s)
        out = s[start:end]

    elif method == "lastIndexOf":
        s = str(recv)
        needle = str(args[0]) if args else ""
        if len(args) > 1 and args[1] is not None:
            try:
                start = int(args[1])
            except Exception:
                start = 0
            out = s.rfind(needle, start)
        else:
            out = s.rfind(needle)

    elif method == "indexOf":
        s = str(recv)
        needle = str(args[0]) if args else ""
        if len(args) > 1 and args[1] is not None:
            try:
                start = int(args[1])
            except Exception:
                start = 0
            out = s.find(needle, start)
        else:
            out = s.find(needle)

    else:
        # Unimplemented method -> no-op
        out = None

    owner._set(regs, inst.get("dst"), out)