#!/usr/bin/env python3
"""Validate the round-1 network address book without third-party dependencies."""

from __future__ import annotations

import csv
import re
import sys
from collections import Counter
from datetime import date
from pathlib import Path
from urllib.parse import urlparse

ROOT = Path(__file__).resolve().parents[1]
DATA = ROOT / "data" / "entities.csv"
REQUIRED = [
    "id", "name", "category", "scope", "region", "homepage",
    "directory_url", "role", "source_url", "status", "verified_at", "notes",
]
CATEGORIES = {
    "governance-identifiers", "standards", "registry", "dns", "interconnection",
    "routing-security", "incident-response", "physical-infrastructure", "operator-community",
}
SCOPES = {"global", "regional", "regional-community"}
STATUSES = {"verified", "partial", "lead", "stale"}
ID_RE = re.compile(r"^[a-z0-9]+(?:-[a-z0-9]+)*$")


def valid_url(value: str) -> bool:
    parsed = urlparse(value)
    return parsed.scheme == "https" and bool(parsed.netloc)


def main() -> int:
    errors: list[str] = []
    with DATA.open(newline="", encoding="utf-8") as handle:
        reader = csv.DictReader(handle)
        if reader.fieldnames != REQUIRED:
            errors.append(f"CSV columns differ from required schema: {reader.fieldnames!r}")
        rows = list(reader)

    ids = Counter(row.get("id", "") for row in rows)
    for row_number, row in enumerate(rows, start=2):
        ident = row.get("id", "")
        prefix = f"row {row_number} ({ident or 'missing-id'})"
        for field in REQUIRED[:-1]:  # notes may be blank
            if not row.get(field, "").strip():
                errors.append(f"{prefix}: missing {field}")
        if not ID_RE.fullmatch(ident):
            errors.append(f"{prefix}: invalid id")
        if row.get("category") not in CATEGORIES:
            errors.append(f"{prefix}: unknown category {row.get('category')!r}")
        if row.get("scope") not in SCOPES:
            errors.append(f"{prefix}: unknown scope {row.get('scope')!r}")
        if row.get("status") not in STATUSES:
            errors.append(f"{prefix}: unknown status {row.get('status')!r}")
        for field in ("homepage", "directory_url", "source_url"):
            if not valid_url(row.get(field, "")):
                errors.append(f"{prefix}: {field} must be an https URL")
        try:
            checked = date.fromisoformat(row.get("verified_at", ""))
            if checked > date.today():
                errors.append(f"{prefix}: verified_at is in the future")
        except ValueError:
            errors.append(f"{prefix}: verified_at must be YYYY-MM-DD")

    for ident, count in ids.items():
        if count > 1:
            errors.append(f"duplicate id {ident!r}: {count} rows")

    required_docs = [
        ROOT / "README.md",
        ROOT / "docs" / "02-first-round-investigation.md",
        ROOT / "address-book" / "README.md",
        ROOT / "research" / "next-round.md",
    ]
    for path in required_docs:
        if not path.is_file():
            errors.append(f"missing required document: {path.relative_to(ROOT)}")

    if errors:
        print("Validation failed:")
        for error in errors:
            print(f"- {error}")
        return 1

    counts = Counter(row["category"] for row in rows)
    print(f"Validated {len(rows)} entities across {len(counts)} categories.")
    for category, count in sorted(counts.items()):
        print(f"- {category}: {count}")
    return 0


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