from __future__ import annotations

from urllib.parse import urlparse

from starlette.requests import Request
from starlette.responses import RedirectResponse

LOCALES = ("pt", "en")
DEFAULT = "pt"
COOKIE = "lang"
COOKIE_MAX_AGE = 60 * 60 * 24 * 365

_PT = {
    "tagline": "Observatório público de trackers BitTorrent",
    "nav_trackers": "Trackers",
    "nav_trackers_sub": "lista",
    "nav_lists": "Criar lista",
    "nav_lists_sub": "smart",
    "nav_github": "GitHub",
    "nav_github_sub": "código",
    "footer_utc": "medições em UTC",
    "footer_disclaimer": "Não é um tracker BitTorrent · não indexa torrents",
    "stats_label": "Resumo",
    "stats_monitored": "monitorados",
    "stats_up": "ativos",
    "stats_degraded": "degradados",
    "stats_down": "indisponíveis",
    "stats_unknown": "desconhecidos",
    "stats_last_import": "última importação",
    "stats_last_probe": "última medição",
    "filter_search": "Busca",
    "filter_search_ph": "hostname ou URL",
    "filter_protocol": "Protocolo",
    "filter_any": "qualquer",
    "filter_status": "Status",
    "filter_source": "Origem",
    "filter_sort": "Ordenar",
    "sort_checked": "última verificação",
    "sort_latency": "latência",
    "sort_url": "URL",
    "sort_status": "status",
    "sort_protocol": "protocolo",
    "filter_order": "Ordem",
    "order_desc": "desc",
    "order_asc": "asc",
    "filter_submit": "Filtrar",
    "col_tracker": "Tracker",
    "col_protocol": "Protocolo",
    "col_status": "Status",
    "col_uptime7": "Uptime 7d",
    "col_latency": "Latência med.",
    "col_ip": "IPv4 / IPv6",
    "col_asn": "ASN / rede",
    "col_sources": "Fontes",
    "col_aliases": "Aliases",
    "col_last_check": "Última verificação",
    "copy": "copiar",
    "copy_btn": "Copiar",
    "copied": "copiado",
    "th_latency": "Latência",
    "provisional": "provisório",
    "empty_inventory": "Nenhum tracker no inventário ainda.",
    "pagination": "Paginação",
    "prev": "Anterior",
    "next": "Próxima",
    "page_of": "Página {page} / {pages} ({total})",
    "lists_title": "Criar lista",
    "lists_heading": "Smart List",
    "lists_blurb": (
        "Seleção de trackers estáveis e com diversidade de infraestrutura. "
        "Classificações das fontes externas não substituem as medições próprias."
    ),
    "min_uptime": "Uptime mínimo (0–1)",
    "max_latency": "Latência máxima (ms)",
    "filter_ip": "IP",
    "filter_limit": "Quantidade (1–50)",
    "min_age": "Idade mínima (dias)",
    "diversity": "Diversidade de infraestrutura",
    "diversity_on": "ligada",
    "diversity_off": "desligada",
    "generate": "Gerar",
    "selected_count": "trackers selecionados.",
    "download_txt": "Baixar TXT",
    "open_json": "Abrir JSON",
    "permalink": "URL permanente",
    "back": "voltar",
    "score": "pontuação",
    "score_insufficient": "insuficiente",
    "uptime_24h": "Uptime 24h",
    "uptime_7d": "Uptime 7d",
    "uptime_30d": "Uptime 30d",
    "latency_med_7d": "Latência med. 7d",
    "latency_p95": "Latência p95 7d",
    "valid_rate": "Respostas válidas 7d",
    "measurements": "Medições",
    "tracking": "Acompanhamento",
    "days": "dias",
    "spark_label": "Latências recentes",
    "sources": "Origens",
    "best_at_source": "best na origem",
    "stable_at_source": "stable na origem",
    "live_at_source": "live na origem",
    "seen": "visto",
    "no_source": "Sem associação de origem",
    "dns": "DNS",
    "terminal_cname": "CNAME terminal",
    "infra_fp": "Fingerprint de infraestrutura",
    "asn": "ASN",
    "unknown": "desconhecido",
    "country": "País",
    "no_dns": "Sem registros DNS armazenados",
    "shared_infra": "Infraestrutura compartilhada",
    "shared_infra_blurb": (
        "Outros endpoints com o mesmo fingerprint (sinal, não prova de operador):"
    ),
    "recent_history": "Histórico recente",
    "when": "Quando (UTC)",
    "valid": "Válida",
    "error": "Erro",
    "yes": "sim",
    "no": "não",
    "no_probes": "Sem medições ainda",
    "not_found": "Tracker não encontrado",
    "bootstrap_empty": (
        "Inventário vazio: não foi possível importar fontes na inicialização ({exc}). "
        "O site está no ar; tente novamente com `python -m app.cli import-sources`."
    ),
    "bootstrap_stale": (
        "Listas desatualizadas: não foi possível importar fontes na inicialização ({exc}). "
        "O site está no ar; tente novamente com `python -m app.cli import-sources`."
    ),
}

_EN = {
    "tagline": "Public observatory of BitTorrent trackers",
    "nav_trackers": "Trackers",
    "nav_trackers_sub": "list",
    "nav_lists": "Build a list",
    "nav_lists_sub": "smart",
    "nav_github": "GitHub",
    "nav_github_sub": "code",
    "footer_utc": "measurements in UTC",
    "footer_disclaimer": "Not a BitTorrent tracker · does not index torrents",
    "stats_label": "Overview",
    "stats_monitored": "watched",
    "stats_up": "up",
    "stats_degraded": "degraded",
    "stats_down": "down",
    "stats_unknown": "unknown",
    "stats_last_import": "last import",
    "stats_last_probe": "last probe",
    "filter_search": "Search",
    "filter_search_ph": "hostname or URL",
    "filter_protocol": "Protocol",
    "filter_any": "any",
    "filter_status": "Status",
    "filter_source": "Source",
    "filter_sort": "Sort",
    "sort_checked": "last check",
    "sort_latency": "latency",
    "sort_url": "URL",
    "sort_status": "status",
    "sort_protocol": "protocol",
    "filter_order": "Order",
    "order_desc": "desc",
    "order_asc": "asc",
    "filter_submit": "Filter",
    "col_tracker": "Tracker",
    "col_protocol": "Protocol",
    "col_status": "Status",
    "col_uptime7": "Uptime 7d",
    "col_latency": "Median latency",
    "col_ip": "IPv4 / IPv6",
    "col_asn": "ASN / net",
    "col_sources": "Sources",
    "col_aliases": "Aliases",
    "col_last_check": "Last check",
    "copy": "copy",
    "copy_btn": "Copy",
    "copied": "copied",
    "th_latency": "Latency",
    "provisional": "provisional",
    "empty_inventory": "No trackers in the inventory yet.",
    "pagination": "Pagination",
    "prev": "Previous",
    "next": "Next",
    "page_of": "Page {page} / {pages} ({total})",
    "lists_title": "Build a list",
    "lists_heading": "Smart List",
    "lists_blurb": (
        "Stable trackers with some infrastructure spread. "
        "Labels from the upstream lists do not replace our own probes."
    ),
    "min_uptime": "Min uptime (0–1)",
    "max_latency": "Max latency (ms)",
    "filter_ip": "IP",
    "filter_limit": "Count (1–50)",
    "min_age": "Min age (days)",
    "diversity": "Infrastructure diversity",
    "diversity_on": "on",
    "diversity_off": "off",
    "generate": "Build",
    "selected_count": "trackers selected.",
    "download_txt": "Download TXT",
    "open_json": "Open JSON",
    "permalink": "Permalink",
    "back": "back",
    "score": "score",
    "score_insufficient": "not enough data",
    "uptime_24h": "Uptime 24h",
    "uptime_7d": "Uptime 7d",
    "uptime_30d": "Uptime 30d",
    "latency_med_7d": "Median latency 7d",
    "latency_p95": "p95 latency 7d",
    "valid_rate": "Valid replies 7d",
    "measurements": "Probes",
    "tracking": "Watched for",
    "days": "days",
    "spark_label": "Recent latencies",
    "sources": "Sources",
    "best_at_source": "best at source",
    "stable_at_source": "stable at source",
    "live_at_source": "live at source",
    "seen": "seen",
    "no_source": "No source association",
    "dns": "DNS",
    "terminal_cname": "Terminal CNAME",
    "infra_fp": "Infrastructure fingerprint",
    "asn": "ASN",
    "unknown": "unknown",
    "country": "Country",
    "no_dns": "No stored DNS records",
    "shared_infra": "Shared infrastructure",
    "shared_infra_blurb": (
        "Other endpoints with the same fingerprint (a hint, not proof of the same operator):"
    ),
    "recent_history": "Recent history",
    "when": "When (UTC)",
    "valid": "Valid",
    "error": "Error",
    "yes": "yes",
    "no": "no",
    "no_probes": "No probes yet",
    "not_found": "Tracker not found",
    "bootstrap_empty": (
        "Empty inventory: could not import sources on startup ({exc}). "
        "The site is up; retry with `python -m app.cli import-sources`."
    ),
    "bootstrap_stale": (
        "Stale lists: could not import sources on startup ({exc}). "
        "The site is up; retry with `python -m app.cli import-sources`."
    ),
}

STRINGS = {"pt": _PT, "en": _EN}

_BOOTSTRAP_KEYS = {
    "empty_import": "bootstrap_empty",
    "stale_import": "bootstrap_stale",
}


def normalize_lang(code: str | None) -> str:
    if not code:
        return DEFAULT
    tag = code.strip().lower().replace("_", "-")
    if tag in LOCALES:
        return tag
    if tag.startswith("en"):
        return "en"
    if tag.startswith("pt"):
        return "pt"
    return DEFAULT


def from_accept_language(header: str | None) -> str:
    if not header:
        return DEFAULT
    for part in header.split(","):
        tag = part.split(";", 1)[0].strip()
        if not tag:
            continue
        return normalize_lang(tag)
    return DEFAULT


def resolve_lang(request: Request) -> str:
    cookie = request.cookies.get(COOKIE)
    if cookie in LOCALES:
        return cookie
    return from_accept_language(request.headers.get("accept-language"))


def html_lang(lang: str) -> str:
    return "pt-BR" if lang == "pt" else "en"


def translate(lang: str, key: str, **kwargs: object) -> str:
    table = STRINGS.get(lang) or STRINGS[DEFAULT]
    text = table.get(key) or STRINGS[DEFAULT].get(key) or key
    if kwargs:
        return text.format(**kwargs)
    return text


def translator(lang: str):
    def _t(key: str, **kwargs: object) -> str:
        return translate(lang, key, **kwargs)

    return _t


def encode_bootstrap_note(kind: str, exc: object) -> str:
    return f"{kind}|{exc}"


def render_bootstrap_note(lang: str, raw: str | None) -> str:
    if not raw:
        return ""
    kind, sep, detail = raw.partition("|")
    key = _BOOTSTRAP_KEYS.get(kind)
    if key and sep:
        return translate(lang, key, exc=detail)
    return raw


def safe_back(request: Request) -> str:
    ref = request.headers.get("referer")
    if not ref:
        return "/"
    parsed = urlparse(ref)
    if parsed.netloc and parsed.netloc != request.url.netloc:
        return "/"
    path = parsed.path or "/"
    if path.startswith("/lang"):
        return "/"
    if parsed.query:
        return f"{path}?{parsed.query}"
    return path


def lang_redirect(request: Request, code: str) -> RedirectResponse:
    lang = normalize_lang(code)
    resp = RedirectResponse(safe_back(request), status_code=303)
    resp.set_cookie(
        COOKIE,
        lang,
        max_age=COOKIE_MAX_AGE,
        path="/",
        samesite="lax",
        httponly=True,
    )
    return resp