"""Read dependency manifests and explain each library in plain English.

A non-coder has no idea what `chromadb` or `axios` is. We parse
requirements.txt / package.json / pyproject.toml and attach a one-line,
jargon-free description from a curated map (with a generic fallback). No model
call needed for the common case.
"""
from __future__ import annotations

import json
import re

from schema import Dependency

# Curated plain-English blurbs for libraries a vibe-coder is likely to have.
# Keys are matched case-insensitively against the bare package name.
KNOWN: dict[str, str] = {
    # AI / LLM
    "openai": "Talks to OpenAI's AI models (like ChatGPT) to generate text.",
    "anthropic": "Talks to Anthropic's Claude AI models to generate text.",
    "langchain": "A toolkit for chaining AI steps together (load → search → answer).",
    "langchain-community": "Extra connectors for LangChain (databases, loaders, tools).",
    "llama-index": "Helps an AI answer questions over your own documents.",
    "transformers": "Runs open-source AI models on your own machine.",
    "sentence-transformers": "Turns text into numbers (embeddings) so it can be searched by meaning.",
    "chromadb": "A 'memory' database that stores text as numbers for fast meaning-search.",
    "faiss-cpu": "A fast search engine for finding similar pieces of text by meaning.",
    "tiktoken": "Counts how many tokens (word-pieces) your text uses for an AI model.",
    "huggingface-hub": "Downloads AI models and datasets from Hugging Face.",
    "gradio": "Builds the web interface you click on, with very little code.",
    "streamlit": "Builds a simple data web app you click on.",
    # Web / API
    "flask": "A small web server — handles requests from the browser.",
    "fastapi": "A modern web server for building fast APIs.",
    "django": "A big all-in-one web framework (pages, database, admin).",
    "uvicorn": "Runs FastAPI apps and serves them to the browser.",
    "requests": "Fetches things from the internet (calls other websites/APIs).",
    "httpx": "Fetches things from the internet, with async support.",
    "aiohttp": "Fetches things from the internet without waiting (async).",
    "express": "A small web server for Node.js — handles browser requests.",
    "axios": "Fetches things from the internet from the browser or Node.",
    "next": "A React framework for full websites (pages + server).",
    "react": "Builds interactive user interfaces in the browser.",
    "react-dom": "Connects React to the actual web page.",
    "vue": "Builds interactive user interfaces in the browser.",
    # Data
    "pandas": "Works with tables of data (like a spreadsheet in code).",
    "numpy": "Does fast math on big lists of numbers.",
    "pydantic": "Checks that data has the right shape and types.",
    "sqlalchemy": "Talks to databases using Python instead of raw SQL.",
    "psycopg2": "Connects Python to a PostgreSQL database.",
    "psycopg2-binary": "Connects Python to a PostgreSQL database.",
    "pymongo": "Connects Python to a MongoDB database.",
    "redis": "Talks to Redis, a very fast in-memory store/cache.",
    # Files / media
    "pillow": "Opens and edits images.",
    "pypdf": "Reads text out of PDF files.",
    "pypdf2": "Reads text out of PDF files.",
    "python-docx": "Reads and writes Word documents.",
    "beautifulsoup4": "Pulls data out of web pages (HTML).",
    "opencv-python": "Computer vision — works with images and video.",
    # Utility
    "python-dotenv": "Loads secret settings from a .env file.",
    "dotenv": "Loads secret settings from a .env file.",
    "tqdm": "Shows a progress bar while something runs.",
    "click": "Builds command-line tools.",
    "pytest": "Runs your automated tests.",
    "modal": "Runs your code on cloud GPUs without managing servers.",
    "lodash": "A grab-bag of handy helper functions for JavaScript.",
    "dotenv-flow": "Loads secret settings from .env files.",
}

# Best-effort 'this looks old / risky' flags for a non-coder.
RISKY = {
    "psycopg2": "Prefer the maintained build 'psycopg2-binary' or 'psycopg[binary]'.",
    "pypdf2": "PyPDF2 is deprecated — 'pypdf' is the maintained successor.",
    "request": "Looks like a typo for 'requests'.",
}

_REQ_LINE = re.compile(r"^\s*([A-Za-z0-9_.\-]+)")


def _plain(name: str) -> str:
    return KNOWN.get(name.lower(), f"A library called '{name}'. Used somewhere in the project.")


def _dep(name: str, manifest: str) -> Dependency:
    low = name.lower()
    return Dependency(name=name, manifest=manifest, plain=_plain(name),
                      risky=low in RISKY)


def parse_requirements(text: str, manifest: str = "requirements.txt") -> list[Dependency]:
    out: list[Dependency] = []
    for line in text.splitlines():
        line = line.strip()
        if not line or line.startswith(("#", "-")):
            continue
        m = _REQ_LINE.match(line)
        if m:
            out.append(_dep(m.group(1), manifest))
    return out


def parse_package_json(text: str, manifest: str = "package.json") -> list[Dependency]:
    out: list[Dependency] = []
    try:
        data = json.loads(text)
    except (json.JSONDecodeError, ValueError):
        return out
    for key in ("dependencies", "devDependencies"):
        for name in (data.get(key) or {}):
            out.append(_dep(name, manifest))
    return out


def parse_pyproject(text: str, manifest: str = "pyproject.toml") -> list[Dependency]:
    """Cheap TOML scan — avoids a tomllib dependency for one simple need."""
    out: list[Dependency] = []
    # [project] dependencies = ["foo>=1", "bar"]
    for block in re.findall(r"dependencies\s*=\s*\[(.*?)\]", text, re.DOTALL):
        for item in re.findall(r"['\"]([A-Za-z0-9_.\-]+)", block):
            out.append(_dep(item, manifest))
    # [tool.poetry.dependencies]\n foo = "^1"
    poetry = re.search(r"\[tool\.poetry\.dependencies\](.*?)(?:\n\[|\Z)", text, re.DOTALL)
    if poetry:
        for name in re.findall(r"^\s*([A-Za-z0-9_.\-]+)\s*=", poetry.group(1), re.MULTILINE):
            if name.lower() != "python":
                out.append(_dep(name, manifest))
    return out


def parse_manifest(filename: str, text: str) -> list[Dependency]:
    base = filename.lower()
    if base == "requirements.txt":
        return parse_requirements(text, filename)
    if base == "package.json":
        return parse_package_json(text, filename)
    if base == "pyproject.toml":
        return parse_pyproject(text, filename)
    return []