#!/usr/bin/env python3
"""Scan Nexa BaZi files for mixed interface and prompt-variable names."""

from __future__ import annotations

import argparse
import os
import re
import sys
from dataclasses import dataclass
from pathlib import Path


SKILL_DIR = Path(__file__).resolve().parents[1]
DEFAULT_RULES = SKILL_DIR / "references" / "nexa-forbidden-names.md"

SEVERITY_ORDER = {"review": 0, "warn": 1, "error": 2}

EXCLUDE_DIRS = {
    ".git",
    ".hg",
    ".svn",
    ".idea",
    ".vscode",
    "__pycache__",
    "node_modules",
    "vendor",
    "dist",
    "build",
    "coverage",
    ".next",
    ".nuxt",
    ".venv",
    "venv",
}

TEXT_EXTENSIONS = {
    ".c",
    ".cc",
    ".cpp",
    ".cs",
    ".css",
    ".csv",
    ".go",
    ".h",
    ".hpp",
    ".html",
    ".java",
    ".js",
    ".json",
    ".jsx",
    ".kt",
    ".lua",
    ".md",
    ".mjs",
    ".php",
    ".py",
    ".rb",
    ".rs",
    ".scss",
    ".sh",
    ".sql",
    ".svelte",
    ".swift",
    ".toml",
    ".ts",
    ".tsx",
    ".txt",
    ".vue",
    ".xml",
    ".yaml",
    ".yml",
}


@dataclass(frozen=True)
class Rule:
    severity: str
    current: str
    preferred: str
    concept: str
    reason: str


@dataclass(frozen=True)
class Issue:
    path: Path
    line_no: int
    line: str
    rule: Rule


def split_md_row(line: str) -> list[str]:
    stripped = line.strip()
    if not stripped.startswith("|") or not stripped.endswith("|"):
        return []
    return [cell.strip().strip("`").strip() for cell in stripped.strip("|").split("|")]


def parse_rules(path: Path) -> list[Rule]:
    header: list[str] | None = None
    rules: list[Rule] = []

    for raw_line in path.read_text(encoding="utf-8").splitlines():
        cells = split_md_row(raw_line)
        if not cells:
            continue
        if {"severity", "current", "preferred"}.issubset(set(cells)):
            header = cells
            continue
        if cells and all(set(cell) <= {"-"} for cell in cells):
            continue
        if not header or len(cells) < len(header):
            continue

        row = dict(zip(header, cells))
        severity = row.get("severity", "").lower()
        if severity not in SEVERITY_ORDER:
            continue
        current = row.get("current", "").strip()
        preferred = row.get("preferred", "").strip()
        if not current or not preferred:
            continue
        rules.append(
            Rule(
                severity=severity,
                current=current,
                preferred=preferred,
                concept=row.get("concept", ""),
                reason=row.get("reason", ""),
            )
        )

    return rules


def iter_files(paths: list[Path]) -> list[Path]:
    found: list[Path] = []
    for path in paths:
        if not path.exists():
            print(f"warning: path does not exist: {path}", file=sys.stderr)
            continue
        if path.is_file():
            if is_text_candidate(path):
                found.append(path)
            continue
        for root, dirs, files in os.walk(path):
            dirs[:] = [d for d in dirs if d not in EXCLUDE_DIRS]
            for name in files:
                candidate = Path(root) / name
                if is_text_candidate(candidate):
                    found.append(candidate)
    return found


def is_text_candidate(path: Path) -> bool:
    return path.suffix.lower() in TEXT_EXTENSIONS


def identifier_pattern(name: str) -> re.Pattern[str] | None:
    if not re.match(r"^[A-Za-z_][A-Za-z0-9_]*$", name):
        return None
    return re.compile(r"(?<![A-Za-z0-9_])" + re.escape(name) + r"(?![A-Za-z0-9_])")


def line_has_rule(line: str, rule: Rule) -> bool:
    pattern = identifier_pattern(rule.current)
    if pattern:
        return bool(pattern.search(line))
    return rule.current in line


def scan(paths: list[Path], rules: list[Rule], min_severity: str) -> list[Issue]:
    min_rank = SEVERITY_ORDER[min_severity]
    active_rules = [rule for rule in rules if SEVERITY_ORDER[rule.severity] >= min_rank]
    issues: list[Issue] = []

    for path in iter_files(paths):
        try:
            text = path.read_text(encoding="utf-8")
        except UnicodeDecodeError:
            try:
                text = path.read_text(encoding="utf-8-sig")
            except UnicodeDecodeError:
                continue

        for line_no, line in enumerate(text.splitlines(), start=1):
            for rule in active_rules:
                if line_has_rule(line, rule):
                    issues.append(Issue(path=path, line_no=line_no, line=line.strip(), rule=rule))
    return issues


def print_rules(rules: list[Rule]) -> None:
    for rule in rules:
        print(f"{rule.severity}\t{rule.current}\t{rule.preferred}\t{rule.concept}")


def main() -> int:
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("paths", nargs="*", type=Path, help="files or directories to scan")
    parser.add_argument("--rules", type=Path, default=DEFAULT_RULES, help="path to nexa-forbidden-names.md")
    parser.add_argument(
        "--min-severity",
        choices=sorted(SEVERITY_ORDER, key=SEVERITY_ORDER.get),
        default="review",
        help="minimum severity to report",
    )
    parser.add_argument("--list-rules", action="store_true", help="print loaded rules and exit")
    parser.add_argument("--no-fail", action="store_true", help="always exit 0")
    args = parser.parse_args()

    if not args.rules.exists():
        print(f"rules file not found: {args.rules}", file=sys.stderr)
        return 2

    rules = parse_rules(args.rules)
    if args.list_rules:
        print_rules(rules)
        return 0

    if not args.paths:
        parser.error("provide at least one file or directory")

    issues = scan(args.paths, rules, args.min_severity)
    if not issues:
        print("No Nexa BaZi contract naming issues found.")
        return 0

    for issue in issues:
        rule = issue.rule
        print(f"{issue.path}:{issue.line_no}: {rule.current} -> {rule.preferred} [{rule.severity}]")
        print(f"  concept: {rule.concept}")
        print(f"  reason: {rule.reason}")
        print(f"  line: {issue.line}")

    counts: dict[str, int] = {"error": 0, "warn": 0, "review": 0}
    for issue in issues:
        counts[issue.rule.severity] += 1
    print(f"\n{len(issues)} issue(s) found: {counts['error']} error, {counts['warn']} warn, {counts['review']} review.")

    blocking = any(issue.rule.severity in {"error", "warn"} for issue in issues)
    return 0 if args.no_fail or not blocking else 1


if __name__ == "__main__":
    raise SystemExit(main())