import logging
import re
from pathlib import Path
from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from .versions import BuildVersion, SupportedVersion

logger = logging.getLogger("dpn")


def _format_md_table(columns: list[str], rows: list[list[str]]) -> str:
    head = f"{' | '.join(columns)}\n{' | '.join(['---'] * len(columns))}"
    body = "\n".join([" | ".join(row) for row in rows])
    return f"{head}\n{body}\n"


def _replace(name: str, replacement: str, document: str) -> str:
    start = f"<!-- {name}_START -->\n"
    end = f"<!-- {name}_END -->"
    repl = f"{start}\n{replacement}\n{end}"
    return re.sub(f"{start}(.*?){end}", repl, document, flags=re.MULTILINE | re.DOTALL)


def update_dynamic_readme(
    versions: "list[BuildVersion]",
    python_versions: "list[SupportedVersion]",
    node_versions: "list[SupportedVersion]",
    dry_run: bool = False,
) -> None:
    """Read out current README, format fresh README, write back possible changes"""
    readme_path = Path("README.md")
    readme = readme_path.read_text()

    readme_new = format_readme(versions, python_versions, node_versions, readme)
    if readme == readme_new:
        logger.debug("Regenerated readme matches existing")
        return

    if not dry_run:
        readme_path.write_text(readme_new)
    else:
        print(readme_new)


def format_readme(
    versions: "list[BuildVersion]",
    python_versions: "list[SupportedVersion]",
    node_versions: "list[SupportedVersion]",
    readme: str,
) -> str:
    """Format fresh README based on passed in version. Replaces the whole table with new versions."""
    tags_table = format_tags(versions)
    readme_fresh = _replace("TAGS", tags_table, readme)

    supported_versions_table = format_supported_versions(python_versions, node_versions)
    return _replace("SUPPORTED_VERSIONS", supported_versions_table, readme_fresh)


def format_tags(versions: "list[BuildVersion]") -> str:
    headings = ["Tag", "Python version", "Node.js version", "Distro"]
    rows = [[f"`{v.key}`", v.python_canonical, v.nodejs_canonical, v.distro] for v in versions]
    return _format_md_table(headings, rows)


def format_supported_versions(
    python_versions: "list[SupportedVersion]",
    node_versions: "list[SupportedVersion]",
) -> str:
    def _as_rows(versions: "list[SupportedVersion]") -> list[list[str]]:
        return [[ver.version, ver.start, ver.end] for ver in sorted(versions, key=lambda x: x.start, reverse=True)]

    python_table = _format_md_table(["Python version", "Start", "End"], _as_rows(python_versions))
    node_table = _format_md_table(["Node.js version", "Start", "End"], _as_rows(node_versions))

    return f"{python_table}\n{node_table}"