import csv
import glob
import hashlib
import json
from pathlib import Path


ROOT = Path(__file__).resolve().parents[1]
LAYOUT_PATH = ROOT / "USECODE" / "EUSECODE_extracted" / "class_layout_index.tsv"
EVENT_PATH = ROOT / "USECODE" / "EUSECODE_extracted" / "class_event_index.tsv"
CHUNKS_DIR = ROOT / "USECODE" / "EUSECODE_extracted" / "chunks"

FAMILIES = {
    "BOOT": {
        "classes": ["AND_BOOT", "BRO_BOOT", "COR_BOOT", "REE_BOOT", "VAR_BOOT"],
        "slots": [0x0A, 0x0F, 0x10],
    },
    "SURCAM": {
        "classes": ["SURCAMNS", "SURCAMEW"],
        "slots": [0x20, 0x21, 0x22],
    },
    "JELY": {
        "classes": ["JELYHACK", "JELYH2"],
        "slots": [0x01],
    },
}


def parse_hex(value: str) -> int:
    return int(value, 16)


def common_prefix_length(blobs: list[bytes]) -> int:
    if not blobs:
        return 0
    limit = min(len(blob) for blob in blobs)
    for index in range(limit):
        current = blobs[0][index]
        if any(blob[index] != current for blob in blobs[1:]):
            return index
    return limit


def common_suffix_length(blobs: list[bytes]) -> int:
    return common_prefix_length([blob[::-1] for blob in blobs])


def first_diff_positions(blobs: list[bytes], limit: int = 8) -> list[int]:
    positions: list[int] = []
    max_len = max(len(blob) for blob in blobs)
    for index in range(max_len):
        values = {blob[index] if index < len(blob) else None for blob in blobs}
        if len(values) > 1:
            positions.append(index)
        if len(positions) >= limit:
            break
    return positions


def load_layouts(targets: set[str]) -> dict[str, dict[str, str]]:
    layouts: dict[str, dict[str, str]] = {}
    with LAYOUT_PATH.open("r", encoding="utf-8", newline="") as handle:
        reader = csv.DictReader(handle, delimiter="\t")
        for row in reader:
            if row["class_name_hint"] in targets:
                layouts[row["class_name_hint"]] = row
    return layouts


def load_events(targets: set[str]) -> dict[str, list[dict[str, str]]]:
    events: dict[str, list[dict[str, str]]] = {}
    with EVENT_PATH.open("r", encoding="utf-8", newline="") as handle:
        reader = csv.DictReader(handle, delimiter="\t")
        for row in reader:
            if row["class_name_hint"] in targets:
                events.setdefault(row["class_name_hint"], []).append(row)
    for rows in events.values():
        rows.sort(key=lambda row: parse_hex(row["slot"]))
    return events


def resolve_chunk(data_offset: int) -> Path:
    matches = glob.glob(str(CHUNKS_DIR / f"chunk_*_off_{data_offset:06X}_len_*.bin"))
    if len(matches) != 1:
        raise RuntimeError(f"chunk lookup failed for 0x{data_offset:06X}: {matches}")
    return Path(matches[0])


def build_rows() -> dict[tuple[str, int], dict[str, object]]:
    targets = {name for family in FAMILIES.values() for name in family["classes"]}
    layouts = load_layouts(targets)
    events = load_events(targets)
    rows_by_key: dict[tuple[str, int], dict[str, object]] = {}

    for class_name, layout in layouts.items():
        chunk_path = resolve_chunk(parse_hex(layout["data_offset"]))
        blob = chunk_path.read_bytes()
        code_base_minus_one = parse_hex(layout["code_base_minus_one"])
        nonzero_rows = [row for row in events[class_name] if parse_hex(row["raw_code_offset"]) != 0]
        offsets = sorted({parse_hex(row["raw_code_offset"]) for row in nonzero_rows})

        for row in nonzero_rows:
            slot = parse_hex(row["slot"])
            code_offset = parse_hex(row["raw_code_offset"])
            start = code_base_minus_one + code_offset
            next_offsets = [offset for offset in offsets if offset > code_offset]
            end = code_base_minus_one + next_offsets[0] if next_offsets else len(blob)
            body = blob[start:end]
            rows_by_key[(class_name, slot)] = {
                "class_name": class_name,
                "slot": slot,
                "event_name_hint": row["event_name_hint"],
                "raw_event_entry_word": row["raw_event_entry_word"],
                "raw_code_offset": row["raw_code_offset"],
                "start": start,
                "end": end,
                "length": len(body),
                "sha1": hashlib.sha1(body).hexdigest(),
                "preview": body[:16].hex(" "),
                "chunk_path": str(chunk_path).replace("\\", "/"),
                "body": body,
            }

    return rows_by_key


def main() -> None:
    rows_by_key = build_rows()
    for family_name, family in FAMILIES.items():
        print(f"## {family_name}")
        for slot in family["slots"]:
            print(f"SLOT 0x{slot:02X}")
            subset = [rows_by_key[(class_name, slot)] for class_name in family["classes"]]
            for row in subset:
                print(
                    "\t".join(
                        [
                            str(row["class_name"]),
                            str(row["event_name_hint"]),
                            str(row["raw_event_entry_word"]),
                            str(row["raw_code_offset"]),
                            f"{row['start']:04X}-{row['end']:04X}",
                            str(row["length"]),
                            str(row["sha1"])[:12],
                            str(row["preview"]),
                            str(row["chunk_path"]),
                        ]
                    )
                )

            groups: dict[str, list[str]] = {}
            for row in subset:
                groups.setdefault(str(row["sha1"]), []).append(str(row["class_name"]))
            blobs = [row["body"] for row in subset]
            print("identical_groups=" + json.dumps(list(groups.values())))
            print(
                f"common_prefix_len={common_prefix_length(blobs)} "
                f"common_suffix_len={common_suffix_length(blobs)}"
            )
            print("first_diff_positions=" + json.dumps(first_diff_positions(blobs)))
            print()


if __name__ == "__main__":
    main()