"""Regenerate resources/GachaBannerMapping.json from the live import.

Run from the repository root after the roster changes:

    python tools/build_gacha_banner_mapping.py

Stable-ID rules: existing (gacha_id -> avatar_id) pairs are preserved exactly;
only avatars missing from the current mapping receive NEW IDs (max+1). Never
re-sort or renumber, so a banner ID always means the same avatar. The mapping
is the backend half of the custom per-character banner presentation: each
banner ID (900001+) maps to one imported avatar with a configured first Eidolon
cost. Nothing here is an official Client banner row.
"""

import json
import re
import sys
from pathlib import Path

ROOT = Path(__file__).resolve().parent.parent
MAPPING = ROOT / "resources" / "GachaBannerMapping.json"
BANNER_ID_BASE = 900001


def main() -> int:
    freesr = json.loads((ROOT / "freesr-data.json").read_text(encoding="utf-8"))
    avatars = sorted(int(k) for k in freesr.get("avatars", {}).keys())
    eidolon = json.loads(
        (ROOT / "resources" / "EidolonConfig.json").read_text(encoding="utf-8")
    ).get("avatars", {})
    catalog = json.loads(
        (ROOT / "resources" / "PreviewGameplayCatalog.json").read_text(encoding="utf-8")
    )
    client_digest = catalog.get("client_assembly_sha256", "")
    if not re.fullmatch(r"[0-9a-f]{64}", client_digest) or not catalog.get("evidence_id"):
        raise ValueError("Current captured catalog identity/provenance is missing")
    captured_ids = {row["GachaID"] for row in catalog.get("tables", {}).get("gacha", [])}

    drawable = []
    skipped_no_eidolon = []
    for avatar in avatars:
        row = eidolon.get(str(avatar))
        ranks = row.get("ranks", []) if row else []
        if not ranks or not ranks[0].get("cost"):
            skipped_no_eidolon.append(avatar)
            continue
        drawable.append(avatar)

    existing = {}
    if MAPPING.exists():
        previous = json.loads(MAPPING.read_text(encoding="utf-8"))
        if previous.get("client_assembly_sha256") != client_digest:
            raise ValueError("Mapping and current captured catalog belong to different Clients")
        known_ids = set()
        for banner in previous.get("banners", []):
            avatar_id, banner_id = banner["avatar_id"], banner["gacha_id"]
            if (
                type(avatar_id) is not int or avatar_id <= 0
                or type(banner_id) is not int or not BANNER_ID_BASE <= banner_id <= 0xFFFFFFFF
                or avatar_id in existing or banner_id in known_ids or banner_id in captured_ids
            ):
                raise ValueError("Duplicate, invalid or colliding existing banner identity")
            existing[avatar_id] = banner_id
            known_ids.add(banner_id)

    used = set(existing.values())
    next_id = max(used, default=BANNER_ID_BASE - 1) + 1
    banners = []
    added = []
    # Retain unavailable identities as disabled reservations. Dropping them
    # would allow a smaller future roster to reuse an old character's ID.
    for avatar in sorted(set(drawable) | set(existing)):
        gacha_id = existing.get(avatar)
        if gacha_id is None:
            while next_id in used or next_id in captured_ids:
                next_id += 1
            if next_id > 0xFFFFFFFF:
                raise ValueError("Custom banner identity namespace exhausted")
            gacha_id = next_id
            used.add(gacha_id)
            next_id += 1
            added.append((gacha_id, avatar))
        banners.append(
            {
                "gacha_id": gacha_id,
                "avatar_id": avatar,
                "roster_available": avatar in drawable,
                "provenance": "sandbox custom banner; avatar from imported roster; not official Client banner config",
            }
        )
    banners.sort(key=lambda b: b["gacha_id"])
    out = {
        "format_version": 1,
        "source": "Generated from freesr-data.json avatars + resources/EidolonConfig.json by tools/build_gacha_banner_mapping.py; stable IDs: existing pairs preserved, new avatars get max+1.",
        "note": "Custom per-character banner mapping for the custom gacha presentation. Banner IDs use a 900000+ sandbox namespace that cannot collide with the Client captured GachaBasicInfo rows (1001/4001/2001/2002/3001/3002). Draws grant the mapped avatar; duplicates convert at its configured first Eidolon cost; first acquisition of a not-yet-owned avatar is rejected until the avatar acquisition path exists.",
        "client_assembly_sha256": client_digest,
        "banners": banners,
    }
    MAPPING.write_text(
        json.dumps(out, ensure_ascii=False, indent=1) + chr(10), encoding="utf-8"
    )
    print(
        f"active banners: {len(drawable)} (reserved identities {len(banners)}, kept {len(existing)}, newly assigned {len(added)}, "
        f"skipped without eidolon config: {skipped_no_eidolon})"
    )
    return 0


if __name__ == "__main__":
    sys.exit(main())