"""Browser-reachable addresses written into generated HTML pages.

The settings dialog is the source of truth. A value saved in
``system_settings.json`` wins over ``config.yaml`` and the built-in default,
so a deployment can point new pages at a domain users can actually open
without editing or restarting from a config file.
"""

from __future__ import annotations

import logging
from urllib.parse import urlparse

from deerflow.config.html_runtime_config import (
    DEFAULT_HTML_MAP_TILE_URL,
    DEFAULT_HTML_RUNTIME_BASE_URL,
)

logger = logging.getLogger(__name__)

_HTML_RUNTIME_SUFFIX = "/api/public/html-runtime"


def normalize_html_runtime_base_url(value: str) -> str:
    """Return an absolute runtime base, appending the public asset path when omitted."""

    raw = str(value or "").strip()
    if not raw:
        raise ValueError("请填写用户浏览器能够访问的 HTML 运行库地址")
    if any(character.isspace() for character in raw):
        raise ValueError("HTML 运行库地址不能包含空格")
    parsed = urlparse(raw)
    if parsed.scheme not in {"http", "https"} or not parsed.netloc:
        raise ValueError("HTML 运行库地址需要以 http:// 或 https:// 开头，并包含域名或 IP")
    if parsed.username or parsed.password:
        raise ValueError("HTML 运行库地址不能包含账号或密码")
    if parsed.query or parsed.fragment:
        raise ValueError("HTML 运行库地址不需要查询参数")
    path = parsed.path.rstrip("/")
    if path in {"", "/"}:
        path = _HTML_RUNTIME_SUFFIX
    return f"{parsed.scheme}://{parsed.netloc}{path}"


def normalize_html_map_tile_url(value: str) -> str:
    """Return a Leaflet tile template containing the x/y/z placeholders."""

    raw = str(value or "").strip()
    if not raw:
        raise ValueError("请填写地图瓦片地址")
    if any(character.isspace() for character in raw):
        raise ValueError("地图瓦片地址不能包含空格")
    parsed = urlparse(raw)
    if parsed.scheme not in {"http", "https"} or not parsed.netloc:
        raise ValueError("地图瓦片地址需要以 http:// 或 https:// 开头，并包含域名或 IP")
    if parsed.username or parsed.password:
        raise ValueError("地图瓦片地址不能包含账号或密码")
    lowered = raw.lower()
    missing = [token for token in ("{z}", "{x}", "{y}") if token not in lowered]
    if missing:
        raise ValueError("地图瓦片地址需要包含 {z}、{x}、{y} 三个占位符")
    return raw


def html_runtime_base_url(fallback: str | None = None) -> str:
    """Return the runtime base used when writing or serving generated HTML."""

    saved = _saved("base_url")
    if saved:
        try:
            return normalize_html_runtime_base_url(saved)
        except ValueError:
            logger.warning("Ignoring invalid saved HTML runtime base URL")
    return _first_valid_base(fallback, _config_value("base_url"), DEFAULT_HTML_RUNTIME_BASE_URL)


def html_map_tile_url(fallback: str | None = None) -> str:
    """Return the Leaflet tile template injected into deerflow-runtime.js."""

    saved = _saved("map_tile_url")
    if saved:
        try:
            return normalize_html_map_tile_url(saved)
        except ValueError:
            logger.warning("Ignoring invalid saved HTML map tile URL")
    return _first_valid_tile(fallback, _config_value("map_tile_url"), DEFAULT_HTML_MAP_TILE_URL)


def _saved(field: str) -> str:
    try:
        from deerflow.config.system_settings import load_system_settings

        block = load_system_settings().html_runtime
        return str(getattr(block, field, "") or "").strip()
    except Exception:
        logger.debug("HTML runtime settings are unavailable", exc_info=True)
        return ""


def _config_value(field: str) -> str:
    try:
        from deerflow.config import get_app_config

        runtime = get_app_config().html_runtime
        return str(getattr(runtime, field, "") or "").strip()
    except Exception:
        logger.debug("HTML runtime config fallback is unavailable", exc_info=True)
        return ""


def _first_valid_base(*candidates: str | None) -> str:
    for candidate in candidates:
        if not candidate or not str(candidate).strip():
            continue
        try:
            return normalize_html_runtime_base_url(str(candidate))
        except ValueError:
            continue
    return DEFAULT_HTML_RUNTIME_BASE_URL


def _first_valid_tile(*candidates: str | None) -> str:
    for candidate in candidates:
        if not candidate or not str(candidate).strip():
            continue
        try:
            return normalize_html_map_tile_url(str(candidate))
        except ValueError:
            continue
    return DEFAULT_HTML_MAP_TILE_URL