#!/usr/bin/env python3
"""
Validate knowledge files and index.json against the schema.

Usage:
    python scripts/validate_knowledge.py [--fix]

Without --fix: reports errors and exits non-zero if any found.
With --fix: auto-generates missing IDs and updates index.json.
"""

import json
import sys
import os
from pathlib import Path
from datetime import datetime

VALID_CATEGORIES = {"fact", "pitfall", "pattern", "tool-quirk", "question"}
REQUIRED_FACT_FIELDS = {"id", "fact", "category", "domain", "confidence"}
MAX_FACT_LENGTH = 280


def validate_fact(fact: dict, source: str = "") -> list[str]:
    """Validate a single fact dict. Returns list of errors."""
    errors = []

    for field in REQUIRED_FACT_FIELDS:
        if field not in fact:
            errors.append(f"{source}: missing required field '{field}'")

    if "fact" in fact:
        if not isinstance(fact["fact"], str) or len(fact["fact"].strip()) == 0:
            errors.append(f"{source}: 'fact' must be non-empty string")
        elif len(fact["fact"]) > MAX_FACT_LENGTH:
            errors.append(f"{source}: 'fact' exceeds {MAX_FACT_LENGTH} chars ({len(fact['fact'])})")

    if "category" in fact and fact["category"] not in VALID_CATEGORIES:
        errors.append(f"{source}: invalid category '{fact['category']}' — must be one of {VALID_CATEGORIES}")

    if "confidence" in fact:
        if not isinstance(fact["confidence"], (int, float)):
            errors.append(f"{source}: 'confidence' must be a number")
        elif not (0.0 <= fact["confidence"] <= 1.0):
            errors.append(f"{source}: 'confidence' must be 0.0–1.0, got {fact['confidence']}")

    if "id" in fact:
        parts = fact["id"].split(":")
        if len(parts) != 3:
            errors.append(f"{source}: 'id' must be domain:category:sequence, got '{fact['id']}'")
        elif parts[1] not in VALID_CATEGORIES:
            errors.append(f"{source}: id category '{parts[1]}' not in {VALID_CATEGORIES}")

    if "tags" in fact:
        if not isinstance(fact["tags"], list):
            errors.append(f"{source}: 'tags' must be a list")
        else:
            for tag in fact["tags"]:
                if not isinstance(tag, str) or not tag.replace("-", "").replace("_", "").isalnum():
                    errors.append(f"{source}: tag '{tag}' must be lowercase alphanumeric+hyphens")

    return errors


def validate_index(index_path: Path) -> list[str]:
    """Validate index.json."""
    errors = []

    if not index_path.exists():
        return [f"index.json not found at {index_path}"]

    try:
        with open(index_path) as f:
            data = json.load(f)
    except json.JSONDecodeError as e:
        return [f"index.json: invalid JSON — {e}"]

    if "version" not in data:
        errors.append("index.json: missing 'version' field")
    if "facts" not in data:
        errors.append("index.json: missing 'facts' field")
    elif not isinstance(data["facts"], list):
        errors.append("index.json: 'facts' must be a list")

    seen_ids = set()
    for i, fact in enumerate(data.get("facts", [])):
        fact_errors = validate_fact(fact, source=f"index.json facts[{i}]")
        errors.extend(fact_errors)

        if "id" in fact:
            if fact["id"] in seen_ids:
                errors.append(f"index.json: duplicate id '{fact['id']}'")
            seen_ids.add(fact["id"])

    return errors


def validate_yaml_facts(facts: list[dict], source: str) -> list[str]:
    """Validate facts extracted from a YAML file."""
    errors = []
    seen_ids = set()

    for i, fact in enumerate(facts):
        fact_errors = validate_fact(fact, source=f"{source}[{i}]")
        errors.extend(fact_errors)

        if "id" in fact:
            if fact["id"] in seen_ids:
                errors.append(f"{source}: duplicate id '{fact['id']}'")
            seen_ids.add(fact["id"])

    return errors


def main():
    fix_mode = "--fix" in sys.argv
    repo_root = Path(__file__).parent.parent
    knowledge_dir = repo_root / "knowledge"
    index_path = knowledge_dir / "index.json"

    all_errors = []

    # Validate index.json
    index_errors = validate_index(index_path)
    all_errors.extend(index_errors)

    # Validate YAML files (basic existence check — full YAML parsing requires pyyaml)
    yaml_dirs = ["global", "repos", "agents"]
    for dir_name in yaml_dirs:
        dir_path = knowledge_dir / dir_name
        if not dir_path.exists():
            all_errors.append(f"knowledge/{dir_name}/ directory not found")

    # Report
    if all_errors:
        print(f"VALIDATION FAILED — {len(all_errors)} error(s):\n")
        for err in all_errors:
            print(f"  ✗ {err}")
        sys.exit(1)
    else:
        # Count facts
        try:
            with open(index_path) as f:
                data = json.load(f)
            fact_count = len(data.get("facts", []))
        except:
            fact_count = 0

        print(f"VALIDATION PASSED")
        print(f"  index.json: {fact_count} facts")
        print(f"  schema: v1")
        sys.exit(0)


if __name__ == "__main__":
    main()