#!/usr/bin/env python3
"""
Duplicate detection for CmdForge tools using text similarity.

Finds tools that may be duplicates or very similar to existing tools.
Uses TF-IDF vectorization and cosine similarity for comparison.

Usage:
    # Check a tool against all existing tools
    python scripts/similarity.py path/to/tool/config.yaml

    # Check against tools in a specific directory
    python scripts/similarity.py path/to/tool/config.yaml --against ~/.cmdforge/

    # Find all similar pairs in a directory
    python scripts/similarity.py --scan ~/.cmdforge/

    # Set similarity threshold (default: 0.7)
    python scripts/similarity.py --threshold 0.8 path/to/tool/config.yaml

    # Output as JSON
    python scripts/similarity.py --json path/to/tool/config.yaml
"""

import argparse
import json
import math
import re
import sys
from collections import Counter
from dataclasses import dataclass, field
from pathlib import Path
from typing import Optional

import yaml


@dataclass
class SimilarityMatch:
    """A similarity match between two tools."""
    tool1_name: str
    tool1_path: str
    tool2_name: str
    tool2_path: str
    similarity: float  # 0.0 to 1.0
    match_type: str  # "duplicate", "similar", "related"

    def to_dict(self) -> dict:
        return {
            "tool1": {"name": self.tool1_name, "path": self.tool1_path},
            "tool2": {"name": self.tool2_name, "path": self.tool2_path},
            "similarity": self.similarity,
            "match_type": self.match_type,
        }


@dataclass
class ToolText:
    """Extracted text from a tool for similarity comparison."""
    name: str
    path: str
    text: str
    tokens: list[str] = field(default_factory=list)
    tfidf: dict = field(default_factory=dict)


# Similarity thresholds
DUPLICATE_THRESHOLD = 0.9   # >= 0.9 is likely a duplicate
SIMILAR_THRESHOLD = 0.7     # >= 0.7 is very similar
RELATED_THRESHOLD = 0.5     # >= 0.5 is related


def load_tool_config(path: Path) -> Optional[dict]:
    """Load tool configuration from YAML file."""
    if path.is_dir():
        config_file = path / "config.yaml"
    else:
        config_file = path

    if not config_file.exists():
        return None

    with open(config_file) as f:
        return yaml.safe_load(f)


def extract_tool_text(config: dict, path: str) -> ToolText:
    """Extract all meaningful text from a tool config."""
    texts = []

    # Name and description
    name = config.get("name", "")
    texts.append(name)
    texts.append(config.get("description", ""))

    # Category and tags
    texts.append(config.get("category", ""))
    tags = config.get("tags", [])
    if isinstance(tags, list):
        texts.extend(tags)

    # Steps - extract prompts and code
    for step in config.get("steps", []):
        if step.get("type") == "prompt":
            texts.append(step.get("prompt", ""))
        elif step.get("type") == "code":
            # Extract meaningful parts from code (comments, strings)
            code = step.get("code", "")
            # Add variable names
            texts.append(code)

    # Arguments
    for arg in config.get("arguments", []):
        texts.append(arg.get("flag", ""))
        texts.append(arg.get("description", ""))
        texts.append(arg.get("variable", ""))

    # Combine and clean
    combined = " ".join(texts)
    return ToolText(name=name, path=path, text=combined)


def tokenize(text: str) -> list[str]:
    """Tokenize text into words, removing stopwords."""
    # Convert to lowercase and extract words
    words = re.findall(r'\b[a-z]{2,}\b', text.lower())

    # Remove common stopwords
    stopwords = {
        "the", "a", "an", "and", "or", "but", "in", "on", "at", "to", "for",
        "of", "with", "by", "from", "as", "is", "was", "are", "were", "been",
        "be", "have", "has", "had", "do", "does", "did", "will", "would",
        "could", "should", "may", "might", "must", "shall", "can", "this",
        "that", "these", "those", "it", "its", "you", "your", "we", "our",
        "they", "their", "he", "his", "she", "her", "if", "then", "else",
        "when", "where", "which", "who", "what", "how", "all", "each",
        "every", "both", "few", "more", "most", "other", "some", "such",
        "no", "not", "only", "same", "so", "than", "too", "very", "just",
        "also", "now", "here", "there", "any", "into", "out", "up", "down",
    }

    return [w for w in words if w not in stopwords]


def compute_tfidf(documents: list[ToolText]) -> None:
    """Compute TF-IDF vectors for all documents (modifies in place)."""
    # Tokenize all documents
    for doc in documents:
        doc.tokens = tokenize(doc.text)

    # Compute document frequencies
    doc_freq = Counter()
    for doc in documents:
        unique_tokens = set(doc.tokens)
        doc_freq.update(unique_tokens)

    num_docs = len(documents)

    # Compute TF-IDF for each document
    for doc in documents:
        term_freq = Counter(doc.tokens)
        total_terms = len(doc.tokens) or 1

        tfidf = {}
        for term, count in term_freq.items():
            tf = count / total_terms
            # Add 1 to avoid division by zero
            idf = math.log((num_docs + 1) / (doc_freq[term] + 1)) + 1
            tfidf[term] = tf * idf

        doc.tfidf = tfidf


def cosine_similarity(vec1: dict, vec2: dict) -> float:
    """Compute cosine similarity between two TF-IDF vectors."""
    # Get all terms
    all_terms = set(vec1.keys()) | set(vec2.keys())

    if not all_terms:
        return 0.0

    # Compute dot product and magnitudes
    dot_product = 0.0
    mag1 = 0.0
    mag2 = 0.0

    for term in all_terms:
        v1 = vec1.get(term, 0.0)
        v2 = vec2.get(term, 0.0)
        dot_product += v1 * v2
        mag1 += v1 * v1
        mag2 += v2 * v2

    mag1 = math.sqrt(mag1)
    mag2 = math.sqrt(mag2)

    if mag1 == 0 or mag2 == 0:
        return 0.0

    return dot_product / (mag1 * mag2)


def classify_similarity(score: float) -> str:
    """Classify similarity score into a match type."""
    if score >= DUPLICATE_THRESHOLD:
        return "duplicate"
    elif score >= SIMILAR_THRESHOLD:
        return "similar"
    elif score >= RELATED_THRESHOLD:
        return "related"
    return "different"


def find_similar(tool: ToolText, corpus: list[ToolText], threshold: float = RELATED_THRESHOLD) -> list[SimilarityMatch]:
    """Find tools in corpus similar to the given tool."""
    matches = []

    for other in corpus:
        if other.path == tool.path:
            continue

        similarity = cosine_similarity(tool.tfidf, other.tfidf)

        if similarity >= threshold:
            match_type = classify_similarity(similarity)
            matches.append(SimilarityMatch(
                tool1_name=tool.name,
                tool1_path=tool.path,
                tool2_name=other.name,
                tool2_path=other.path,
                similarity=similarity,
                match_type=match_type,
            ))

    # Sort by similarity descending
    matches.sort(key=lambda m: m.similarity, reverse=True)
    return matches


def scan_directory(directory: Path, threshold: float = RELATED_THRESHOLD) -> list[SimilarityMatch]:
    """Scan a directory for similar tool pairs."""
    # Load all tools
    tools = []
    for entry in directory.iterdir():
        config_file = None
        if entry.is_dir():
            config_file = entry / "config.yaml"
        elif entry.suffix in [".yaml", ".yml"]:
            config_file = entry

        if config_file and config_file.exists():
            config = load_tool_config(config_file)
            if config:
                tool_text = extract_tool_text(config, str(entry))
                tools.append(tool_text)

    if len(tools) < 2:
        return []

    # Compute TF-IDF
    compute_tfidf(tools)

    # Find all similar pairs
    matches = []
    seen_pairs = set()

    for tool in tools:
        for other in tools:
            if tool.path >= other.path:  # Avoid duplicates
                continue

            pair_key = (tool.path, other.path)
            if pair_key in seen_pairs:
                continue
            seen_pairs.add(pair_key)

            similarity = cosine_similarity(tool.tfidf, other.tfidf)

            if similarity >= threshold:
                match_type = classify_similarity(similarity)
                matches.append(SimilarityMatch(
                    tool1_name=tool.name,
                    tool1_path=tool.path,
                    tool2_name=other.name,
                    tool2_path=other.path,
                    similarity=similarity,
                    match_type=match_type,
                ))

    # Sort by similarity descending
    matches.sort(key=lambda m: m.similarity, reverse=True)
    return matches


def load_corpus(directory: Path) -> list[ToolText]:
    """Load all tools from a directory as ToolText objects."""
    tools = []

    for entry in directory.iterdir():
        config_file = None
        if entry.is_dir():
            config_file = entry / "config.yaml"
        elif entry.suffix in [".yaml", ".yml"]:
            config_file = entry

        if config_file and config_file.exists():
            config = load_tool_config(config_file)
            if config:
                tool_text = extract_tool_text(config, str(entry))
                tools.append(tool_text)

    return tools


def print_match(match: SimilarityMatch, verbose: bool = False):
    """Print a similarity match to console."""
    # Match type emoji
    type_emoji = {
        "duplicate": "🔴",
        "similar": "🟠",
        "related": "🟡",
    }

    emoji = type_emoji.get(match.match_type, "⚪")
    bar = "█" * int(match.similarity * 20) + "░" * (20 - int(match.similarity * 20))

    print(f"  {emoji} {match.match_type.upper()} [{bar}] {match.similarity:.2%}")
    print(f"     {match.tool1_name} <-> {match.tool2_name}")

    if verbose:
        print(f"     Paths: {match.tool1_path}")
        print(f"            {match.tool2_path}")


def main():
    parser = argparse.ArgumentParser(
        description="Find similar/duplicate CmdForge tools",
        formatter_class=argparse.RawDescriptionHelpFormatter,
        epilog=__doc__
    )

    parser.add_argument(
        "path",
        type=Path,
        nargs="?",
        help="Tool config file to check"
    )
    parser.add_argument(
        "--against",
        type=Path,
        default=Path.home() / ".cmdforge",
        help="Directory to compare against (default: ~/.cmdforge)"
    )
    parser.add_argument(
        "--scan",
        type=Path,
        metavar="DIR",
        help="Scan directory for all similar pairs"
    )
    parser.add_argument(
        "--threshold", "-t",
        type=float,
        default=RELATED_THRESHOLD,
        help=f"Similarity threshold (default: {RELATED_THRESHOLD})"
    )
    parser.add_argument(
        "--json",
        action="store_true",
        help="Output as JSON"
    )
    parser.add_argument(
        "--verbose", "-v",
        action="store_true",
        help="Show detailed output"
    )

    args = parser.parse_args()

    matches = []

    if args.scan:
        # Scan mode - find all similar pairs
        print(f"Scanning {args.scan} for similar tools...")
        matches = scan_directory(args.scan, args.threshold)
    elif args.path:
        # Check single tool against corpus
        config = load_tool_config(args.path)
        if not config:
            print(f"Error: Could not load tool config from {args.path}", file=sys.stderr)
            return 1

        tool_text = extract_tool_text(config, str(args.path))

        # Load corpus
        corpus = load_corpus(args.against)
        if not corpus:
            print(f"No tools found in {args.against}", file=sys.stderr)
            return 1

        # Add the new tool to corpus for TF-IDF computation
        all_tools = corpus + [tool_text]
        compute_tfidf(all_tools)

        print(f"Checking {tool_text.name} against {len(corpus)} existing tools...")
        matches = find_similar(tool_text, corpus, args.threshold)
    else:
        parser.error("Specify a tool path or use --scan")

    # Output
    if args.json:
        output = [m.to_dict() for m in matches]
        print(json.dumps(output, indent=2))
    else:
        if not matches:
            print("\n✅ No similar tools found above threshold")
        else:
            print(f"\nFound {len(matches)} match(es):\n")
            for match in matches:
                print_match(match, args.verbose)

            # Summary by type
            duplicates = sum(1 for m in matches if m.match_type == "duplicate")
            similar = sum(1 for m in matches if m.match_type == "similar")
            related = sum(1 for m in matches if m.match_type == "related")

            print(f"\n{'─' * 40}")
            print(f"Summary: {duplicates} duplicates, {similar} similar, {related} related")

    # Return code
    has_duplicates = any(m.match_type == "duplicate" for m in matches)
    has_similar = any(m.match_type == "similar" for m in matches)

    if has_duplicates:
        return 2
    elif has_similar:
        return 1
    return 0


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