"""Exporter for RomM's known_bios_files.json.

Keys are "<igdb slug>:<filename>". RomM verifies a firmware file with
`file_size_bytes == int(entry.get("size", 0))` and then one hash among md5,
sha1 and crc, so an entry without a size can never match and an entry
without a hash can never match either. Neither is written.
"""

from __future__ import annotations

import json
import sys
from collections import OrderedDict
from pathlib import Path

sys.path.insert(0, str(Path(__file__).resolve().parent.parent))

from scraper.romm_scraper import SLUG_MAP

from .base_exporter import BaseExporter
from .baseline import NativeFile, NativeSystem, Report

SOURCE_URL = (
    "https://raw.githubusercontent.com/rommapp/romm/master/backend/models"
    "/fixtures/known_bios_files.json"
)


class Exporter(BaseExporter):
    """Write RomM's known_bios_files.json, corrected."""

    # (system, filename) keys the platform itself declares, set by render.
    _platform_keys: frozenset[tuple[str, str]] = frozenset()

    @staticmethod
    def platform_name() -> str:
        return "romm"

    @staticmethod
    def native_filename() -> str:
        return "known_bios_files.json"

    @staticmethod
    def carries() -> frozenset[str]:
        return frozenset({"size", "crc32", "md5", "sha1"})

    @staticmethod
    def native_sources() -> dict[str, str]:
        return {"known_bios_files.json": SOURCE_URL}

    @staticmethod
    def _verifiable(fe: NativeFile) -> bool:
        return bool(fe.size()) and any(
            fe.hash(h) for h in ("md5", "sha1", "crc32")
        )

    @staticmethod
    def _known_platform(native_id: str) -> bool:
        """RomM keys by IGDB platform slug, and only looks up its own.

        A key spelled with one of our slugs (capcom-cps3, snk-neogeo-mvs)
        matches nothing on their side, so it is reported rather than
        written.
        """
        return native_id in SLUG_MAP

    def writable(self, fe: NativeFile, require: str = "") -> bool:
        """What RomM already ships stays; the conditions gate additions.

        An entry of theirs that could never verify is still theirs, and the
        round trip is not the place to decide otherwise. An addition whose
        slug:filename key the platform already holds cannot be written: the
        fixture is a dict, and the second write replaced RomM's Dreamcast
        boot.bin with fbneo's 480-byte file of the same name.
        """
        if fe.platform is not None:
            return True
        if (fe.native_system, fe.name) in self._platform_keys:
            return False
        return self._verifiable(fe) and self._known_platform(fe.native_system)

    def render(
        self,
        systems: dict[str, NativeSystem],
        report: Report,
        originals: dict[str, str],
        scraped: dict | None = None,
    ) -> dict[str, str]:
        output: OrderedDict[str, dict] = OrderedDict()
        self._platform_keys = {
            (system.native_id, fe.name)
            for system in systems.values()
            for fe in system.files
            if fe.platform is not None
        }

        for system in sorted(systems.values(), key=lambda s: s.native_id):
            for fe in sorted(system.files, key=lambda f: f.name):
                if not self.writable(fe):
                    continue
                entry: OrderedDict[str, str] = OrderedDict()
                # The fixture states every value as a string, size included.
                entry["size"] = str(fe.size())
                crc = fe.hash("crc32")
                if crc:
                    entry["crc"] = crc
                md5 = fe.hash("md5")
                if md5:
                    entry["md5"] = md5
                sha1 = fe.hash("sha1")
                if sha1:
                    entry["sha1"] = sha1
                output[f"{system.native_id}:{fe.name}"] = entry

        text = json.dumps(output, indent=2, ensure_ascii=False) + "\n"
        return {self.native_filename(): text}

    def validate(
        self,
        systems: dict[str, NativeSystem],
        produced: dict[str, str],
    ) -> list[str]:
        try:
            data = json.loads(produced[self.native_filename()])
        except json.JSONDecodeError as exc:
            return [f"the JSON does not parse: {exc}"]

        issues: list[str] = []
        for key, entry in data.items():
            slug = key.split(":", 1)[0] if ":" in key else ""
            if not slug:
                issues.append(f"key without a platform slug: {key}")
            elif not self._known_platform(slug):
                issues.append(f"platform slug RomM does not know: {slug}")
            if not entry.get("size"):
                issues.append(f"entry without a size, never verifiable: {key}")
            if not any(entry.get(h) for h in ("md5", "sha1", "crc")):
                issues.append(f"entry without a hash, never verifiable: {key}")

        for system in systems.values():
            for fe in system.files:
                if not self.writable(fe):
                    continue
                if f"{system.native_id}:{fe.name}" not in data:
                    issues.append(f"absent: {system.native_id}/{fe.name}")
        return issues