"""
Scrapes xenia-canary's emit files for the location of each instruction's
semantic implementation function `InstrEmit_<mnem>`.

The files are:
  src/xenia/cpu/ppc/ppc_emit_alu.cc       (integer ALU)
  src/xenia/cpu/ppc/ppc_emit_memory.cc    (loads/stores/cache/sync)
  src/xenia/cpu/ppc/ppc_emit_altivec.cc   (VMX + VMX128)
  src/xenia/cpu/ppc/ppc_emit_fpu.cc       (floating-point)
  src/xenia/cpu/ppc/ppc_emit_control.cc   (branch/CR/SPR/syscall/trap)

Returns, for each mnemonic, the relative file path and the starting line
of the `int InstrEmit_<mnem>(...)` definition.
"""

from __future__ import annotations

from dataclasses import dataclass
from pathlib import Path
import re


CXX_EMIT_FILES = [
    "src/xenia/cpu/ppc/ppc_emit_alu.cc",
    "src/xenia/cpu/ppc/ppc_emit_memory.cc",
    "src/xenia/cpu/ppc/ppc_emit_altivec.cc",
    "src/xenia/cpu/ppc/ppc_emit_fpu.cc",
    "src/xenia/cpu/ppc/ppc_emit_control.cc",
]


@dataclass
class CxxRef:
    mnem: str
    emit_file: str | None = None   # relative to xenia-canary/
    emit_line: int | None = None


def _cxx_ident(mnem: str) -> str:
    """Canary maps '.' in the mnemonic to a trailing 'x' in the C++ symbol
    (e.g. addic. → InstrEmit_addicx)."""
    return mnem.replace(".", "x")


class CxxScraper:
    def __init__(self, repo_root: Path):
        self.canary_root = repo_root / "xenia-canary"
        self._index: dict[str, tuple[str, int]] = {}
        fn_pat = re.compile(r"^\s*int\s+InstrEmit_([A-Za-z_][A-Za-z0-9_]*)\s*\(")
        for rel in CXX_EMIT_FILES:
            path = self.canary_root / rel
            if not path.is_file():
                continue
            for i, line in enumerate(path.read_text(encoding="utf-8").splitlines(), start=1):
                m = fn_pat.match(line)
                if not m:
                    continue
                name = m.group(1)
                self._index.setdefault(name, (rel, i))

    def lookup(self, mnem: str) -> CxxRef:
        ident = _cxx_ident(mnem)
        hit = self._index.get(ident)
        if hit is None:
            return CxxRef(mnem=mnem)
        return CxxRef(mnem=mnem, emit_file=hit[0], emit_line=hit[1])


if __name__ == "__main__":
    root = Path(__file__).resolve().parent.parent.parent
    s = CxxScraper(root)
    for m in ("addx", "addic.", "lwz", "bclrx", "mfspr", "stvx", "vaddfp",
              "vaddfp128", "faddx", "lvsl"):
        r = s.lookup(m)
        print(f"{m:12s}  {r.emit_file}:{r.emit_line}")