#!/usr/bin/env python3
from __future__ import annotations

import re
import sys
from pathlib import Path

ROOT = Path(__file__).resolve().parents[1]
TEMPLATES_DIR = ROOT / "app" / "templates"
PAGES_DIR = TEMPLATES_DIR / "pages"
BASE_FILE = TEMPLATES_DIR / "base.html"
CSS_DIR = ROOT / "app" / "static" / "css"

RULE_EXTENDS = "POL001"
RULE_INLINE_STYLE = "POL002"
RULE_EXTRA_ASSETS = "POL003"
RULE_HEX_OUTSIDE_TOKENS = "POL004"
RULE_PX_SPACING = "POL005"
RULE_BASE_ASSETS = "POL006"

EXTENDS_BASE_RE = re.compile(r"\{%-?\s*extends\s+\"base\.html\"\s*-?%\}")
INLINE_STYLE_RE = re.compile(r"<style\b|style\s*=\s*\"", re.IGNORECASE)
ASSET_LINK_RE = re.compile(r"<link[^>]+rel=\"stylesheet\"|<script[^>]+src=\"", re.IGNORECASE)
HEX_RE = re.compile(r"#[0-9a-fA-F]{3,8}")
PX_SPACING_RE = re.compile(
    r"(?:margin|padding|gap|row-gap|column-gap)\s*:\s*[^;]*\d+px",
    flags=re.IGNORECASE,
)


def err(errors: list[str], path: Path, line_no: int, rule: str, message: str) -> None:
    rel = path.relative_to(ROOT)
    errors.append(f"{rel}:{line_no}: {rule} {message}")


def check_base_assets(errors: list[str]) -> None:
    if not BASE_FILE.exists():
        errors.append(f"{BASE_FILE.relative_to(ROOT)}:1: {RULE_BASE_ASSETS} Missing base.html")
        return

    base_content = BASE_FILE.read_text(encoding="utf-8")
    css_hits = re.findall(r'/static/css/[^\"]+', base_content)
    js_hits = re.findall(r'/static/js/[^\"]+', base_content)

    expected_css = ["/static/css/app.css?v={{ asset_version }}"]
    expected_js = ["/static/js/app.js?v={{ asset_version }}"]

    if css_hits != expected_css:
        errors.append(
            f"{BASE_FILE.relative_to(ROOT)}:1: {RULE_BASE_ASSETS} expected CSS include {expected_css}, found {css_hits}"
        )

    if js_hits != expected_js:
        errors.append(
            f"{BASE_FILE.relative_to(ROOT)}:1: {RULE_BASE_ASSETS} expected JS include {expected_js}, found {js_hits}"
        )


def check_pages_extend_base(errors: list[str]) -> None:
    page_files = sorted(PAGES_DIR.glob("*.html"))
    if not page_files:
        errors.append(f"{PAGES_DIR.relative_to(ROOT)}:1: {RULE_EXTENDS} No page templates found")
        return

    for path in page_files:
        content = path.read_text(encoding="utf-8")
        if not EXTENDS_BASE_RE.search(content):
            err(
                errors,
                path,
                1,
                RULE_EXTENDS,
                "page template must contain {% extends \"base.html\" %}",
            )


def check_templates_inline_and_assets(errors: list[str]) -> None:
    for path in sorted(TEMPLATES_DIR.rglob("*.html")):
        for idx, line in enumerate(path.read_text(encoding="utf-8").splitlines(), start=1):
            if INLINE_STYLE_RE.search(line):
                err(errors, path, idx, RULE_INLINE_STYLE, "inline style or <style> is forbidden")

            if path != BASE_FILE and ASSET_LINK_RE.search(line):
                err(
                    errors,
                    path,
                    idx,
                    RULE_EXTRA_ASSETS,
                    "asset includes are only allowed in templates/base.html",
                )


def check_css_rules(errors: list[str]) -> None:
    for path in sorted(CSS_DIR.rglob("*.css")):
        is_tokens = path.name == "tokens.css"
        for idx, line in enumerate(path.read_text(encoding="utf-8").splitlines(), start=1):
            if not is_tokens and HEX_RE.search(line):
                err(errors, path, idx, RULE_HEX_OUTSIDE_TOKENS, "hex colors are only allowed in tokens.css")

            if not is_tokens and PX_SPACING_RE.search(line):
                err(errors, path, idx, RULE_PX_SPACING, "hard px spacing is forbidden outside tokens.css")


def main() -> int:
    errors: list[str] = []

    check_base_assets(errors)
    check_pages_extend_base(errors)
    check_templates_inline_and_assets(errors)
    check_css_rules(errors)

    if errors:
        print("Policy checks failed:")
        for item in errors:
            print(f"{item}")
        print("Hint: fix violations or move token values into app/static/css/tokens.css")
        return 1

    print("Policy checks passed")
    return 0


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