"""
Research Agent — Autonomous Migration Context Gatherer
======================================================

A separate LLM-driven agent that runs BEFORE the fix agent. It gets up to
12 steps to autonomously investigate what broke and why, using real tools
that fetch live documentation from PyPI, GitHub, Python docs, and the web.

The agent is NOT limited to a hardcoded database. It can:
  - Parse test errors to identify the exact exception and involved packages
  - Look up package info on PyPI (versions, homepage, changelog URL)
  - Fetch actual documentation pages, changelogs, and migration guides
  - Read Python "What's New" pages for specific versions
  - Search GitHub release notes for breaking change details
  - Compare old vs new dependency versions from the task metadata
  - Synthesize all findings into a focused context for the fix agent

The key insight: the model drives the research strategy. We give it good
tools and let it figure out what to look up based on the actual error.
"""

from __future__ import annotations

import json
import logging
import re
import time
from typing import Any, Dict, List, Optional
from urllib.request import urlopen, Request
from urllib.error import URLError

log = logging.getLogger("research_agent")


# ---------------------------------------------------------------------------
# Model family detection
# ---------------------------------------------------------------------------
def _detect_model_family(model_name: str) -> str:
    name_lower = model_name.lower()
    if "gemma" in name_lower:
        return "gemma"
    if "qwen3" in name_lower:
        return "qwen3"
    if "qwen" in name_lower:
        return "qwen2"
    return "unknown"


def _strip_model_artifacts(raw_text: str, family: str) -> str:
    clean = raw_text
    if family == "gemma":
        clean = re.sub(r"<\|channel>thought\n.*?<channel\|>", "", clean, flags=re.DOTALL)
        for tok in ["<turn|>", "<|turn>", "<eos>", "</s>"]:
            clean = clean.replace(tok, "")
    elif family == "qwen3":
        clean = re.sub(r"<think>.*?</think>", "", clean, flags=re.DOTALL)
        # Truncate at first <|im_end|> — everything after is hallucinated
        im_end = clean.find("<|im_end|>")
        if im_end != -1:
            clean = clean[:im_end]
        for tok in ["<|im_end|>", "<|endoftext|>", "<|im_start|>"]:
            clean = clean.replace(tok, "")
    elif family == "qwen2":
        im_end = clean.find("<|im_end|>")
        if im_end != -1:
            clean = clean[:im_end]
        for tok in ["<|im_end|>", "<|endoftext|>", "<|im_start|>"]:
            clean = clean.replace(tok, "")
    else:
        for tok in ["<eos>", "</s>", "<|im_end|>", "<|endoftext|>", "<turn|>", "<|turn>"]:
            clean = clean.replace(tok, "")
    return clean.strip()


# ───────────────────────────────────────────────────────────────
# Research Tools — real, live, no hardcoded DB
# ───────────────────────────────────────────────────────────────

def tool_parse_error(test_output: str) -> str:
    """Parse test output to extract every error, traceback file, and package."""
    errors = []
    packages = set()

    for m in re.finditer(
        r"(ImportError|ModuleNotFoundError|AttributeError|TypeError|NameError|"
        r"SyntaxError|ValueError|DeprecationWarning|RuntimeError|KeyError): (.+)",
        test_output,
    ):
        errors.append(f"{m.group(1)}: {m.group(2).strip()}")
        for pkg in re.finditer(r"'(\w+(?:\.\w+)*)'", m.group(2)):
            top = pkg.group(1).split(".")[0]
            if top not in ("builtins", "importlib", "usr", "work"):
                packages.add(top)

    files = re.findall(r'File "(/work/\S+\.py)", line (\d+)', test_output)
    if not files:
        files = re.findall(r"(/work/\S+\.py):(\d+)", test_output)

    failed = re.search(r"(\d+) (?:failed|error)", test_output)
    passed = re.search(r"(\d+) passed", test_output)

    out = "=== ERROR ANALYSIS ===\n"
    if errors:
        out += f"Errors found ({len(errors)}):\n"
        for e in errors[:15]:
            out += f"  - {e}\n"
    else:
        out += "Could not parse specific errors. Check the raw test output.\n"

    if files:
        unique = list(dict.fromkeys(f"{f}:{ln}" for f, ln in files))
        out += f"\nSource files referenced ({len(unique)}):\n"
        for f in unique[:15]:
            out += f"  - {f}\n"

    if packages:
        out += f"\nPackages involved: {', '.join(sorted(packages))}\n"

    if failed:
        out += f"\nTest summary: {failed.group(0)}"
        if passed:
            out += f", {passed.group(0)}"
        out += "\n"

    return out


def tool_search_pypi(package_name: str) -> str:
    """Fetch package metadata from PyPI: version, summary, homepage, changelog URL."""
    try:
        url = f"https://pypi.org/pypi/{package_name}/json"
        req = Request(url, headers={"User-Agent": "code-migration-research/1.0"})
        with urlopen(req, timeout=10) as resp:
            data = json.loads(resp.read())

        info = data.get("info", {})
        version = info.get("version", "unknown")
        summary = info.get("summary", "")
        home_page = info.get("home_page", "") or ""
        project_urls = info.get("project_urls") or {}

        # Try to find changelog/release notes URL
        changelog_url = ""
        for key in ["Changelog", "Changes", "Release Notes", "History",
                     "Release notes", "CHANGELOG", "What's New"]:
            if key in project_urls:
                changelog_url = project_urls[key]
                break

        # Also grab the GitHub URL if available
        github_url = ""
        for key in ["Source", "Source Code", "Repository", "Homepage", "GitHub"]:
            if key in project_urls:
                val = project_urls[key]
                if "github.com" in val:
                    github_url = val
                    break
        if not github_url and home_page and "github.com" in home_page:
            github_url = home_page

        result = f"Package: {package_name}\n"
        result += f"Latest version: {version}\n"
        result += f"Summary: {summary}\n"
        if home_page:
            result += f"Homepage: {home_page}\n"
        if changelog_url:
            result += f"Changelog URL: {changelog_url}\n"
        if github_url:
            result += f"GitHub: {github_url}\n"

        # List all project URLs for the agent to explore
        if project_urls:
            result += "All project URLs:\n"
            for k, v in project_urls.items():
                result += f"  {k}: {v}\n"

        return result
    except Exception as e:
        return f"PyPI lookup failed for '{package_name}': {e}"


def tool_fetch_url(url: str) -> str:
    """Fetch and return clean text content from any URL. All HTML is stripped.

    Returns up to 5000 chars of readable text content.
    """
    try:
        req = Request(url, headers={
            "User-Agent": "code-migration-research/1.0",
            "Accept": "text/html,application/xhtml+xml,text/plain,*/*",
        })
        with urlopen(req, timeout=15) as resp:
            raw = resp.read().decode("utf-8", errors="replace")

        # Remove script and style blocks entirely
        text = re.sub(r"<script[^>]*>.*?</script>", "", raw, flags=re.DOTALL | re.IGNORECASE)
        text = re.sub(r"<style[^>]*>.*?</style>", "", text, flags=re.DOTALL | re.IGNORECASE)
        # Remove HTML comments
        text = re.sub(r"<!--.*?-->", "", text, flags=re.DOTALL)
        # Replace block-level tags with newlines for readability
        text = re.sub(r"<(?:br|p|div|li|tr|h\d|dt|dd|section|article)[^>]*>", "\n", text, flags=re.IGNORECASE)
        # Strip all remaining HTML tags
        text = re.sub(r"<[^>]+>", " ", text)
        # Decode common HTML entities
        text = text.replace("&amp;", "&").replace("&lt;", "<").replace("&gt;", ">")
        text = text.replace("&quot;", '"').replace("&#39;", "'").replace("&nbsp;", " ")
        text = re.sub(r"&#\d+;", " ", text)
        text = re.sub(r"&\w+;", " ", text)
        # Collapse inline whitespace but keep newlines
        text = re.sub(r"[^\S\n]+", " ", text)
        # Collapse multiple blank lines into one
        text = re.sub(r"\n\s*\n+", "\n\n", text)
        text = text.strip()

        if not text:
            return f"Page at {url} returned empty content after HTML stripping."

        return text[:5000]
    except Exception as e:
        return f"Failed to fetch {url}: {e}"


def tool_fetch_python_docs(version: str) -> str:
    """Fetch the official Python 'What's New' page for a specific version.

    Example: version="3.12" fetches https://docs.python.org/3.12/whatsnew/3.12.html
    Returns the text content focused on breaking changes and removals.
    """
    minor = version.split(".")
    if len(minor) >= 2:
        ver = f"{minor[0]}.{minor[1]}"
    else:
        ver = version

    url = f"https://docs.python.org/{ver}/whatsnew/{ver}.html"
    try:
        req = Request(url, headers={"User-Agent": "code-migration-research/1.0"})
        with urlopen(req, timeout=15) as resp:
            raw = resp.read().decode("utf-8", errors="replace")

        # Strip HTML
        text = re.sub(r"<script[^>]*>.*?</script>", " ", raw, flags=re.DOTALL)
        text = re.sub(r"<style[^>]*>.*?</style>", " ", text, flags=re.DOTALL)
        text = re.sub(r"<[^>]+>", " ", text)
        text = re.sub(r"&nbsp;", " ", text)
        text = re.sub(r"&[a-z]+;", " ", text)
        text = re.sub(r"\s+", " ", text).strip()

        # Try to extract just the "Removed" and "Deprecated" sections
        # by looking for those keywords and grabbing surrounding context
        sections = []
        for keyword in ["Removed", "removed", "Deprecated", "deprecated",
                        "Breaking", "breaking", "Porting"]:
            for m in re.finditer(keyword, text):
                start = max(0, m.start() - 100)
                end = min(len(text), m.end() + 800)
                chunk = text[start:end].strip()
                if chunk and chunk not in sections:
                    sections.append(chunk)

        if sections:
            result = f"Python {ver} What's New — breaking changes:\n\n"
            result += "\n---\n".join(sections[:8])
            return result[:5000]

        # Fallback: return first 5000 chars
        return f"Python {ver} What's New (full page excerpt):\n{text[:5000]}"
    except Exception as e:
        return f"Failed to fetch Python {ver} What's New: {e}"


def tool_search_github_releases(owner: str, repo: str) -> str:
    """Fetch the latest 5 release notes from a GitHub repository.

    Use this to find breaking changes, migration notes, and changelog entries.
    Pass owner and repo separately, e.g. owner="numpy", repo="numpy".
    """
    try:
        url = f"https://api.github.com/repos/{owner}/{repo}/releases?per_page=5"
        req = Request(url, headers={
            "User-Agent": "code-migration-research/1.0",
            "Accept": "application/vnd.github.v3+json",
        })
        with urlopen(req, timeout=10) as resp:
            releases = json.loads(resp.read())

        if not releases:
            return f"No releases found for {owner}/{repo}."

        result = []
        for rel in releases[:5]:
            tag = rel.get("tag_name", "unknown")
            name = rel.get("name", tag)
            body = rel.get("body", "")[:1200]
            result.append(f"=== {name} ({tag}) ===\n{body}")

        return "\n\n".join(result)[:5000]
    except Exception as e:
        return f"GitHub releases lookup failed for {owner}/{repo}: {e}"


def tool_compare_versions(dependency_versions: str, package_name: str) -> str:
    """Extract the installed version of a specific package from the dependency list.

    This helps you know exactly which version is installed so you can look up
    the right migration guide (e.g., numpy 1.x → 2.x has different breaks than 1.24 → 1.26).
    """
    if not dependency_versions:
        return f"No dependency version info available for {package_name}."

    for line in dependency_versions.strip().splitlines():
        line = line.strip()
        if not line:
            continue
        # Parse "package==version" or "package>=version"
        parts = re.split(r"[=><~!]+", line, maxsplit=1)
        if len(parts) >= 2:
            pkg = parts[0].strip().lower().replace("-", "_")
            ver = parts[1].strip()
            if pkg == package_name.lower().replace("-", "_"):
                return f"{package_name} installed version: {ver}"

    return f"Package '{package_name}' not found in dependency list."


def tool_find_changelog(github_url: str) -> str:
    """Given a GitHub repo URL, try to find and fetch the CHANGELOG/CHANGES/HISTORY file.

    Automatically tries common changelog filenames on both main and master branches.
    This is the most reliable way to find breaking changes for a package.

    Example: github_url="https://github.com/numpy/numpy"
    """
    # Extract owner/repo from URL
    m = re.search(r"github\.com/([^/]+)/([^/]+)", github_url)
    if not m:
        return f"Could not parse GitHub owner/repo from: {github_url}"

    owner = m.group(1)
    repo = m.group(2).rstrip("/").replace(".git", "")

    # Try common changelog filenames on common branches
    filenames = [
        "CHANGELOG.md", "CHANGELOG.rst", "CHANGELOG",
        "CHANGES.md", "CHANGES.rst", "CHANGES",
        "HISTORY.md", "HISTORY.rst",
        "NEWS.md", "NEWS.rst",
        "RELEASE_NOTES.md",
    ]
    branches = ["main", "master"]

    for branch in branches:
        for fname in filenames:
            raw_url = f"https://raw.githubusercontent.com/{owner}/{repo}/{branch}/{fname}"
            try:
                req = Request(raw_url, headers={"User-Agent": "code-migration-research/1.0"})
                with urlopen(req, timeout=5) as resp:
                    content = resp.read().decode("utf-8", errors="replace")

                if len(content) < 20:
                    continue

                # Found it — return a useful chunk
                # Try to find breaking/removed/deprecated sections
                sections = []
                for keyword in ["breaking", "removed", "deprecated", "incompatible",
                                "migration", "upgrade", "BREAKING", "Removed", "Deprecated"]:
                    for km in re.finditer(keyword, content, re.IGNORECASE):
                        start = max(0, km.start() - 200)
                        end = min(len(content), km.end() + 1500)
                        chunk = content[start:end].strip()
                        if chunk not in sections:
                            sections.append(chunk)

                if sections:
                    result = f"Found {fname} in {owner}/{repo} ({branch}):\n\n"
                    result += "\n---\n".join(sections[:6])
                    return result[:5000]

                # No keyword matches — return the first 5000 chars
                return f"Found {fname} in {owner}/{repo} ({branch}):\n\n{content[:5000]}"

            except Exception:
                continue

    return f"No changelog file found in {owner}/{repo}. Try search_github_releases or fetch_url with a specific docs URL."


# ───────────────────────────────────────────────────────────────
# Tool registry
# ───────────────────────────────────────────────────────────────

RESEARCH_TOOLS = {
    "parse_error": tool_parse_error,
    "search_pypi": tool_search_pypi,
    "fetch_url": tool_fetch_url,
    "fetch_python_docs": tool_fetch_python_docs,
    "search_github_releases": tool_search_github_releases,
    "compare_versions": tool_compare_versions,
    "find_changelog": tool_find_changelog,
}


# ───────────────────────────────────────────────────────────────
# System prompt — the agent drives the research strategy
# ───────────────────────────────────────────────────────────────

RESEARCH_SYSTEM_PROMPT = """You are a research agent. Your job is to investigate WHY tests are failing
after a Python project's dependencies were upgraded, and find the EXACT fix patterns.

You have these tools (output ONE JSON tool call per turn):

1. parse_error(test_output)
   - Extracts all errors, tracebacks, file paths, and package names from test output
   - ALWAYS call this first to understand what broke

2. compare_versions(dependency_versions, package_name)
   - Shows the exact installed version of a package
   - Use this to know if it's a major version jump (e.g., numpy 1.x → 2.x)

3. search_pypi(package_name)
   - Gets package info from PyPI: latest version, homepage, changelog URL, GitHub URL
   - Use this to find where the docs/changelog live

4. find_changelog(github_url)
   - Given a GitHub URL, finds and fetches the CHANGELOG/CHANGES/HISTORY file
   - Automatically searches common filenames and branches
   - Returns sections mentioning breaking changes, removals, deprecations
   - THIS IS YOUR BEST TOOL for finding what changed between versions

5. fetch_url(url)
   - Fetches any URL and returns text content (HTML stripped)
   - Use this to read specific docs pages, migration guides, or changelog URLs from PyPI

6. fetch_python_docs(version)
   - Fetches the official Python "What's New" page for a version (e.g., "3.12")
   - Shows removed modules, deprecated APIs, breaking changes

7. search_github_releases(owner, repo)
   - Gets recent release notes from GitHub
   - Good for finding breaking changes when there's no changelog file

Output format: {"name": "tool_name", "arguments": {"arg": "value"}}

STRATEGY:
1. parse_error — understand exactly what errors occurred and which packages are involved
2. compare_versions — check what version of the failing package is installed (is it a major bump?)
3. search_pypi — find the package's GitHub URL
4. find_changelog — fetch the changelog from GitHub and look for breaking changes
5. If changelog doesn't have what you need, try search_github_releases or fetch_url on the docs
6. For Python stdlib issues, use fetch_python_docs
7. IMPORTANT: Also check the dependency versions list for ANY major version bumps
   (e.g., numpy 1.x→2.x, pandas 1.x→2.x, Django 3.x→5.x). These often have
   breaking changes that won't show up in the CURRENT test errors but will appear
   after you fix the first error. Research ALL major-bumped packages, not just
   the one currently failing.
8. When you have enough info: {"name": "done", "arguments": {"summary": "YOUR FINDINGS"}}

Your summary MUST include for EACH error:
- The exact error message
- The root cause (what was removed/renamed/moved in which version)
- The EXACT fix: old code → new code replacement
- Which file(s) need to be changed

Also include any POTENTIAL breaking changes from major version bumps in the
dependency list, even if they don't show up in the current test errors yet.
For example, if pandas went from 1.x to 2.x, mention that DataFrame.append()
was removed and the fix is pd.concat().

RULES:
- NEVER call the same tool with the same arguments twice
- Don't just look things up — READ the actual changelog. Use find_changelog.
- Be specific: "replace np.math.factorial with math.factorial" not "check numpy docs"
- You have limited steps — be efficient. parse_error → search_pypi → find_changelog → done.
- If the dependency list shows multiple major version bumps, research ALL of them.
"""


# ───────────────────────────────────────────────────────────────
# Research Agent class
# ───────────────────────────────────────────────────────────────

class ResearchAgent:
    """LLM-driven agent that autonomously researches migration breaking changes."""

    def __init__(self, model, tokenizer, max_steps: int = 12, model_name: str = ""):
        self.model = model
        self.tokenizer = tokenizer
        self.max_steps = max_steps
        self.model_family = _detect_model_family(model_name) if model_name else "unknown"
        self.last_research_steps: List[Dict] = []

    def research(
        self,
        repo_name: str,
        old_python: str,
        new_python: str,
        related_modules: str,
        test_output: str,
        dependency_versions: str = "",
        on_step: Any = None,
    ) -> str:
        """Run the research loop and return migration context for the fix agent."""
        import torch

        log.info("  [RESEARCH] Starting for %s (%s → %s, modules=%s)",
                 repo_name, old_python, new_python, related_modules)

        # Build the initial context with everything the agent needs
        dep_summary = ""
        if dependency_versions:
            dep_summary = f"\nInstalled dependency versions:\n{dependency_versions}\n"

        # Highlight which modules are involved so the agent researches all of them
        modules_note = ""
        if related_modules and "," in related_modules:
            mods = [m.strip() for m in related_modules.split(",")]
            modules_note = (
                f"\nIMPORTANT: This project uses multiple upgraded packages: {', '.join(mods)}. "
                f"Research breaking changes for ALL of them, not just the one in the current error. "
                f"After fixing one error, another package's breaking change may surface.\n"
            )

        initial_context = (
            f"Repository: {repo_name}\n"
            f"Python version migration: {old_python} → {new_python}\n"
            f"Related modules: {related_modules}\n"
            f"{modules_note}"
            f"{dep_summary}\n"
            f"Failing test output (last 3000 chars):\n"
            f"{test_output[-3000:]}\n"
        )

        messages = [
            {"role": "system", "content": RESEARCH_SYSTEM_PROMPT},
            {"role": "user", "content": initial_context},
        ]

        gathered_info: List[str] = []
        research_steps: List[Dict] = []
        seen_calls: set = set()  # track ALL previous calls, not just last

        for step in range(1, self.max_steps + 1):
            if torch.cuda.is_available():
                torch.cuda.empty_cache()

            # Generate
            try:
                text = self.tokenizer.apply_chat_template(
                    messages, tokenize=False, add_generation_prompt=True,
                    **({"enable_thinking": False} if self.model_family == "qwen3" else {}),
                )
                if self.model_family == "gemma":
                    text = text.replace("<|think|>", "")

                inputs = self.tokenizer(text, return_tensors="pt").to(self.model.device)
                input_len = inputs["input_ids"].shape[-1]

                # Build gen kwargs with stop tokens for Qwen
                gen_kwargs = dict(
                    max_new_tokens=400,
                    temperature=0.3,
                    top_p=0.95,
                    do_sample=True,
                    pad_token_id=self.tokenizer.pad_token_id,
                )
                if self.model_family in ("qwen3", "qwen2"):
                    stop_ids = []
                    for tok_str in ["<|im_end|>", "<|endoftext|>"]:
                        tid = self.tokenizer.convert_tokens_to_ids(tok_str)
                        if tid is not None and tid != self.tokenizer.unk_token_id:
                            stop_ids.append(tid)
                    if stop_ids:
                        eos = self.tokenizer.eos_token_id
                        if isinstance(eos, int):
                            stop_ids.append(eos)
                        gen_kwargs["eos_token_id"] = list(set(stop_ids))

                with torch.no_grad():
                    outputs = self.model.generate(**inputs, **gen_kwargs)

                raw = self.tokenizer.decode(outputs[0][input_len:], skip_special_tokens=False)
                del inputs, outputs
                if torch.cuda.is_available():
                    torch.cuda.empty_cache()

                clean = _strip_model_artifacts(raw, self.model_family)

            except Exception as e:
                log.warning("  [RESEARCH] Step %d generation failed: %s", step, e)
                break

            # Parse tool call
            parsed = _parse_research_call(clean)
            tool_name = parsed["tool_name"]
            tool_args = parsed["tool_args"]

            # Done signal
            if tool_name == "done":
                summary = tool_args.get("summary", "")
                if summary:
                    gathered_info.append(f"=== RESEARCH SUMMARY ===\n{summary}")
                log.info("  [RESEARCH] Step %d: done (summary=%d chars)", step, len(summary))
                break

            # Anti-repeat: block any call we've already made
            curr_key = f"{tool_name}:{json.dumps(tool_args, sort_keys=True)}"
            if curr_key in seen_calls:
                log.info("  [RESEARCH] Step %d: already called %s with same args → forcing done", step, tool_name)
                break
            seen_calls.add(curr_key)

            # Execute tool
            result = self._execute_tool(
                tool_name, tool_args,
                test_output=test_output,
                dependency_versions=dependency_versions,
                new_python=new_python,
                related_modules=related_modules,
            )

            gathered_info.append(result)
            args_short = json.dumps(tool_args, default=str)[:150]
            log.info("  [RESEARCH] Step %d: %s(%s) → %d chars",
                     step, tool_name, args_short, len(result))

            research_steps.append({
                "step": step,
                "tool": tool_name,
                "args": tool_args,
                "result": result,
                "model_output": clean,
            })

            # Live callback for streaming steps to the frontend
            if on_step:
                on_step(research_steps[-1])

            # Feed result back to the agent
            messages.append({"role": "assistant", "content": clean})
            messages.append({"role": "user", "content": f"Tool result:\n{result}"})

        self.last_research_steps = research_steps

        if not gathered_info:
            log.warning("  [RESEARCH] No info gathered, returning empty context")
            return "Research agent could not gather migration context. Use general debugging."

        return "\n\n".join(gathered_info)

    def _execute_tool(
        self,
        tool_name: str,
        tool_args: Dict[str, Any],
        *,
        test_output: str,
        dependency_versions: str,
        new_python: str,
        related_modules: str,
    ) -> str:
        """Dispatch a tool call with proper argument handling."""
        try:
            if tool_name == "parse_error":
                return tool_parse_error(test_output)

            elif tool_name == "compare_versions":
                return tool_compare_versions(
                    dependency_versions,
                    tool_args.get("package_name", related_modules),
                )

            elif tool_name == "search_pypi":
                return tool_search_pypi(
                    tool_args.get("package_name", related_modules),
                )

            elif tool_name == "fetch_url":
                url = tool_args.get("url", "")
                if not url:
                    return "Error: fetch_url requires a 'url' argument."
                return tool_fetch_url(url)

            elif tool_name == "fetch_python_docs":
                return tool_fetch_python_docs(
                    tool_args.get("version", new_python),
                )

            elif tool_name == "search_github_releases":
                owner = tool_args.get("owner", "")
                repo = tool_args.get("repo", "")
                if not owner or not repo:
                    return "Error: search_github_releases requires 'owner' and 'repo'."
                return tool_search_github_releases(owner, repo)

            elif tool_name == "find_changelog":
                github_url = tool_args.get("github_url", "")
                if not github_url:
                    return "Error: find_changelog requires a 'github_url' argument."
                return tool_find_changelog(github_url)

            else:
                return f"Unknown tool: {tool_name}. Available: {', '.join(RESEARCH_TOOLS.keys())}"

        except Exception as e:
            return f"Tool '{tool_name}' error: {e}"


def _parse_research_call(text: str) -> Dict[str, Any]:
    """Parse a JSON tool call from model output.

    Finds the FIRST complete JSON object to avoid hallucinated multi-turn content.
    """
    text = text.strip()

    # Strip markdown fences
    if text.startswith("```"):
        lines = text.split("\n")
        lines = [l for l in lines if not l.strip().startswith("```")]
        text = "\n".join(lines).strip()

    # Find first { and match its closing }
    start = text.find("{")
    if start != -1:
        depth = 0
        for i in range(start, len(text)):
            if text[i] == "{":
                depth += 1
            elif text[i] == "}":
                depth -= 1
                if depth == 0:
                    try:
                        data = json.loads(text[start:i + 1])
                        name = data.get("name", data.get("tool_name", ""))
                        args = data.get("arguments", data.get("tool_args", data.get("parameters", {})))
                        if name:
                            return {"tool_name": name, "tool_args": args}
                    except json.JSONDecodeError:
                        pass
                    break

    # Fallback: start with parse_error
    return {"tool_name": "parse_error", "tool_args": {}}