"""把 PAM 部署 Skill 文档加载为简化策略对象。"""

from __future__ import annotations

import re
from pathlib import Path

from .constants import (
    ALLOWED_ACTIONS,
    DEFAULT_PARAMS,
    GLOBAL_ACTION_SEQUENCE,
    IP_ACTION_SEQUENCE,
    REQUIRED_PARAMS,
)
from .models import SkillPolicy


def load_skill_policy(path: str | Path) -> SkillPolicy:
    """读取 Skill markdown，并提取真正参与执行的策略约束。"""
    skill_path = Path(path)
    text = skill_path.read_text(encoding="utf-8")
    name = "pam-auto-deply"
    description = ""

    if text.startswith("---"):
        parts = text.split("---", 2)
        if len(parts) >= 3:
            for line in parts[1].splitlines():
                if line.startswith("name:"):
                    name = line.split(":", 1)[1].strip()
                elif line.startswith("description:"):
                    description = line.split(":", 1)[1].strip()

    parsed_actions = _parse_allowed_actions(text)
    action_sequence = _parse_action_sequence(text)
    ip_action_sequence = tuple(action for action in action_sequence if action in IP_ACTION_SEQUENCE) or IP_ACTION_SEQUENCE
    global_sequence = tuple(action for action in action_sequence if action in GLOBAL_ACTION_SEQUENCE) or GLOBAL_ACTION_SEQUENCE
    required_confirmations = _parse_required_confirmations(text)
    forbidden_actions = _parse_forbidden_actions(text)
    required_params = _parse_required_params(text)

    return SkillPolicy(
        name=name,
        source_path=str(skill_path),
        description=description,
        allowed_actions=parsed_actions or ALLOWED_ACTIONS,
        required_params=required_params or REQUIRED_PARAMS,
        optional_params=DEFAULT_PARAMS.copy(),
        required_confirmations=required_confirmations or ("params", "target_scope", "rollback"),
        action_sequence=global_sequence,
        ip_action_sequence=ip_action_sequence,
        forbidden_actions=forbidden_actions or ("script-main-flow", "auto-rollback", "modify-deploy-scripts"),
    )


def _parse_allowed_actions(text: str) -> tuple[str, ...]:
    """从 skill 文档的 action 表中提取允许的 action。"""
    section = _section_body(text, "### 6.3 可用 action")
    if not section:
        return ()
    actions: list[str] = []
    for raw_line in section.splitlines():
        line = raw_line.strip()
        if not line.startswith("|"):
            continue
        parts = [item.strip() for item in line.strip("|").split("|")]
        if not parts or parts[0] in ("action", "---"):
            continue
        action = parts[0].strip("` ")
        if action in ALLOWED_ACTIONS and action not in actions:
            actions.append(action)
    return tuple(actions)


def _parse_action_sequence(text: str) -> tuple[str, ...]:
    """从主流程章节提取推荐执行顺序。"""
    section = _section_body(text, "### 4.1 正式部署主流程")
    if not section:
        return ()
    found: list[str] = []
    for action in [*GLOBAL_ACTION_SEQUENCE, *IP_ACTION_SEQUENCE]:
        if re.search(rf"\b{re.escape(action)}\b", section) and action not in found:
            found.append(action)
    return tuple(found)


def _parse_required_confirmations(text: str) -> tuple[str, ...]:
    """从强制确认点章节提取确认类型。"""
    section = _section_body(text, "### 4.2 主流程中的强制确认点")
    if not section:
        return ()
    confirmations: list[str] = []
    keyword_map = {
        "参数确认": "params",
        "目标 ip": "target_scope",
        "部署范围": "target_scope",
        "回滚": "rollback",
        "间隔策略": "interval_policy",
    }
    lowered = section.lower()
    for keyword, name in keyword_map.items():
        if keyword in lowered or keyword in section:
            confirmations.append(name)
    return tuple(dict.fromkeys(confirmations))


def _parse_forbidden_actions(text: str) -> tuple[str, ...]:
    """从禁止事项章节提取禁止项。"""
    section = _section_body(text, "### 7.5 明确禁止的做法")
    if not section:
        return ()
    forbidden: list[str] = []
    if "脚本主流程" in section:
        forbidden.append("script-main-flow")
    if "自动执行回滚" in section or "自动回滚" in section:
        forbidden.append("auto-rollback")
    if "修改脚本" in section or "自动生成" in section:
        forbidden.append("modify-deploy-scripts")
    return tuple(dict.fromkeys(forbidden))


def _parse_required_params(text: str) -> tuple[str, ...]:
    """从参数表提取必填脚本字段。"""
    section = _section_body(text, "### 3.1 必填业务参数")
    if not section:
        return ()
    params: list[str] = []
    for raw_line in section.splitlines():
        line = raw_line.strip()
        if not line.startswith("|"):
            continue
        parts = [item.strip() for item in line.strip("|").split("|")]
        if len(parts) < 3 or parts[0] in ("规范字段", "---"):
            continue
        script_field = parts[1].strip("` ")
        required_flag = parts[2]
        if script_field in REQUIRED_PARAMS and required_flag == "是":
            params.append(script_field)
    return tuple(params)


def _section_body(text: str, heading: str) -> str:
    """提取指定 markdown heading 到下一同级 heading 之间的正文。"""
    marker = f"{heading}\n"
    if marker not in text:
        return ""
    _, tail = text.split(marker, 1)
    matches = list(re.finditer(r"^###\s+", tail, flags=re.MULTILINE))
    if matches:
        return tail[: matches[0].start()]
    return tail