app.py

__import__('pysqlite3')
import sys
sys.modules['sqlite3'] = sys.modules.pop('pysqlite3')

import streamlit as st
import plotly.graph_objects as go
import re
from langchain.agents import AgentExecutor, create_tool_calling_agent
from langchain.prompts import ChatPromptTemplate, MessagesPlaceholder
from langchain.tools import tool
from github import Github

st.set_page_config(page_title="AI Code Review Agent", page_icon="🔬", layout="wide", initial_sidebar_state="expanded")

st.markdown("""

<style>

    .stApp { background-color: #0d1117; color: #e6edf3; }

    [data-testid="stSidebar"] { background-color: #161b22; border-right: 1px solid #30363d; }

    .stTextInput input { background-color: #21262d !important; color: #e6edf3 !important; border: 1px solid #30363d !important; border-radius: 6px !important; }

    .stButton button { background: linear-gradient(135deg, #238636, #2ea043) !important; color: white !important; border: none !important; border-radius: 6px !important; font-weight: 600 !important; width: 100%; }

    .stButton button:hover { opacity: 0.85 !important; }

    .review-card { background: #161b22; border: 1px solid #30363d; border-radius: 12px; padding: 1.2rem 1.5rem; margin-bottom: 1rem; }

    .high-card   { border-left: 4px solid #f85149; }

    .medium-card { border-left: 4px solid #d29922; }

    .low-card    { border-left: 4px solid #3fb950; }

    .badge { display: inline-block; padding: 2px 10px; border-radius: 20px; font-size: 0.75rem; font-weight: 700; margin-bottom: 6px; }

    .badge-high   { background: #3d1a1a; color: #f85149; border: 1px solid #f85149; }

    .badge-medium { background: #2d2008; color: #d29922; border: 1px solid #d29922; }

    .badge-low    { background: #0d2818; color: #3fb950; border: 1px solid #3fb950; }

    .diff-add    { background: #0d2818; color: #3fb950; padding: 2px 8px; font-family: monospace; font-size: 0.85rem; }

    .diff-remove { background: #3d1a1a; color: #f85149; padding: 2px 8px; font-family: monospace; font-size: 0.85rem; }

    .diff-ctx    { background: #161b22; color: #8b949e; padding: 2px 8px; font-family: monospace; font-size: 0.85rem; }

    .main-title { font-size: 2rem; font-weight: 800; background: linear-gradient(90deg, #58a6ff, #3fb950); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }

    .subtitle { color: #8b949e; font-size: 0.95rem; }

    .metric-box { background: #161b22; border: 1px solid #30363d; border-radius: 10px; padding: 1rem; text-align: center; }

    .metric-value { font-size: 2rem; font-weight: 800; }

    .metric-label { color: #8b949e; font-size: 0.8rem; }

    .saved-badge { color: #3fb950; font-size: 0.8rem; font-weight: 600; }

</style>

""", unsafe_allow_html=True)

# ─── Session state init ──────────────────────────────────────────
for key in ["saved_provider", "saved_model", "saved_api_key", "saved_github_token"]:
    if key not in st.session_state:
        st.session_state[key] = ""

# ─── LLM factory ─────────────────────────────────────────────────
def get_llm(provider, api_key, model_name):
    if provider == "Groq":
        from langchain_groq import ChatGroq
        return ChatGroq(model=model_name, api_key=api_key, temperature=0)
    elif provider == "Google Gemini":
        from langchain_google_genai import ChatGoogleGenerativeAI
        return ChatGoogleGenerativeAI(model=model_name, google_api_key=api_key, temperature=0)
    elif provider == "OpenAI":
        from langchain_openai import ChatOpenAI
        return ChatOpenAI(model=model_name, api_key=api_key, temperature=0)
    else:
        raise ValueError(f"Unknown provider: {provider}")

# ─── Diff helpers ─────────────────────────────────────────────────
def render_diff_html(patch_text):
    if not patch_text:
        return "<p style='color:#8b949e'>No diff available</p>"
    html = ""
    for line in patch_text.split("\n")[:60]:
        if line.startswith("+") and not line.startswith("+++"):
            html += f'<div class="diff-add">+ {line[1:]}</div>'
        elif line.startswith("-") and not line.startswith("---"):
            html += f'<div class="diff-remove">- {line[1:]}</div>'
        else:
            html += f'<div class="diff-ctx">&nbsp; {line}</div>'
    return html

def build_diff_graph(files_data):
    fig = go.Figure()
    fig.add_trace(go.Bar(name="Additions", x=[f["name"] for f in files_data], y=[f["additions"] for f in files_data], marker_color="#3fb950", hovertemplate="<b>%{x}</b><br>+%{y} lines<extra></extra>"))
    fig.add_trace(go.Bar(name="Deletions", x=[f["name"] for f in files_data], y=[-f["deletions"] for f in files_data], marker_color="#f85149", hovertemplate="<b>%{x}</b><br>-%{y} lines<extra></extra>"))
    fig.update_layout(barmode="relative", paper_bgcolor="#0d1117", plot_bgcolor="#161b22", font=dict(color="#e6edf3"), xaxis=dict(gridcolor="#30363d", tickangle=-30), yaxis=dict(gridcolor="#30363d", title="Lines Changed"), legend=dict(bgcolor="#161b22"), height=350, margin=dict(t=50,b=80,l=40,r=20), title=dict(text="📊 Changes Per File", font=dict(color="#58a6ff", size=16)))
    return fig

def build_severity_chart(high, medium, low):
    fig = go.Figure(go.Pie(labels=["High","Medium","Low"], values=[max(high,0),max(medium,0),max(low,0)], hole=0.6, marker=dict(colors=["#f85149","#d29922","#3fb950"], line=dict(color="#0d1117", width=2)), hovertemplate="<b>%{label}</b>: %{value} issues<extra></extra>"))
    fig.update_layout(paper_bgcolor="#0d1117", font=dict(color="#e6edf3"), legend=dict(bgcolor="#161b22"), height=300, margin=dict(t=50,b=20,l=20,r=20), title=dict(text="🔴 Issue Severity", font=dict(color="#58a6ff", size=16)))
    return fig

# ─── Sidebar ──────────────────────────────────────────────────────
with st.sidebar:
    st.markdown("## ⚙️ Configuration")

    provider = st.selectbox(
        "🤖 LLM Provider",
        ["Groq", "Google Gemini", "OpenAI"],
        index=["Groq","Google Gemini","OpenAI"].index(st.session_state.saved_provider) if st.session_state.saved_provider in ["Groq","Google Gemini","OpenAI"] else 0
    )

    model_name = st.text_input(
        "📦 Model Name (type any model)",
        value=st.session_state.saved_model,
        placeholder="e.g. llama-3.3-70b-versatile"
    )

    api_key = st.text_input(
        f"🔑 {provider} API Key",
        value=st.session_state.saved_api_key,
        type="password",
        placeholder="Paste your API key..."
    )

    github_token = st.text_input(
        "🐙 GitHub Token",
        value=st.session_state.saved_github_token,
        type="password",
        placeholder="ghp_..."
    )

    if st.button("💾 Save Configuration"):
        st.session_state.saved_provider     = provider
        st.session_state.saved_model        = model_name
        st.session_state.saved_api_key      = api_key
        st.session_state.saved_github_token = github_token
        st.success("✅ Saved for this session!")

    if st.session_state.saved_api_key:
        st.markdown('<p class="saved-badge">✓ API key active from session</p>', unsafe_allow_html=True)
    if st.session_state.saved_github_token:
        st.markdown('<p class="saved-badge">✓ GitHub token active from session</p>', unsafe_allow_html=True)

    st.markdown("---")
    st.markdown("**🔄 Agent Flow**")
    st.markdown("1. Fetch PR metadata\n2. Fetch code diff\n3. Analyze changes\n4. Generate review")
    st.caption("Built with LangChain + Streamlit")

# ─── Main UI ──────────────────────────────────────────────────────
st.markdown('<p class="main-title">🔬 AI Code Review Agent</p>', unsafe_allow_html=True)
st.markdown('<p class="subtitle">Autonomous PR analysis — paste any GitHub PR URL below</p>', unsafe_allow_html=True)
st.markdown("---")

pr_url = st.text_input("GitHub PR URL", placeholder="https://github.com/owner/repo/pull/123", label_visibility="collapsed")

col_btn, col_info = st.columns([1, 3])
with col_btn:
    analyze_btn = st.button("🚀 Analyze PR")
with col_info:
    st.caption("The agent autonomously decides which tools to call and in what order.")

# Use saved values as fallback
active_api_key      = api_key      or st.session_state.saved_api_key
active_github_token = github_token or st.session_state.saved_github_token
active_model        = model_name   or st.session_state.saved_model
active_provider     = provider

# ─── Agent execution ──────────────────────────────────────────────
if analyze_btn:
    if not active_api_key or not active_github_token:
        st.error("⚠️ Enter API keys in the sidebar and click 💾 Save Configuration.")
    elif not active_model:
        st.error("⚠️ Enter a model name in the sidebar.")
    elif not pr_url:
        st.error("⚠️ Enter a PR URL.")
    else:
        @st.cache_resource
        def load_github_client(token):
            return Github(token)

        github_client = load_github_client(active_github_token)
        files_data = []

        @tool
        def get_pr_metadata(pr_url: str) -> str:
            """Get the title, description and author of a GitHub PR"""
            try:
                parts = pr_url.strip("/").split("/")
                owner, repo_name, pr_number = parts[-4], parts[-3], int(parts[-1])
                repo = github_client.get_repo(f"{owner}/{repo_name}")
                pr = repo.get_pull(pr_number)
                return f"Title: {pr.title}\nAuthor: {pr.user.login}\nDescription: {pr.body}\nBase: {pr.base.ref} -> Head: {pr.head.ref}"
            except Exception as e:
                return f"Error: {str(e)}"

        @tool
        def get_pr_diff(pr_url: str) -> str:
            """Get the code changes (diff) from a GitHub PR"""
            try:
                parts = pr_url.strip("/").split("/")
                owner, repo_name, pr_number = parts[-4], parts[-3], int(parts[-1])
                repo = github_client.get_repo(f"{owner}/{repo_name}")
                pr = repo.get_pull(pr_number)
                diff_text = ""
                for file in pr.get_files():
                    files_data.append({
                        "name": file.filename.split("/")[-1],
                        "additions": file.additions,
                        "deletions": file.deletions,
                        "patch": file.patch or ""
                    })
                    diff_text += f"\nFile: {file.filename}\n+{file.additions} -{file.deletions}\n"
                    if file.patch:
                        diff_text += file.patch + "\n"
                return diff_text[:4000]
            except Exception as e:
                return f"Error: {str(e)}"

        @tool
        def get_file_content(repo_full_name: str, file_path: str) -> str:
            """Get the full content of a file from a GitHub repository"""
            try:
                repo = github_client.get_repo(repo_full_name)
                content = repo.get_contents(file_path)
                return content.decoded_content.decode("utf-8")[:2000]
            except Exception as e:
                return f"Error: {str(e)}"

        tools = [get_pr_metadata, get_pr_diff, get_file_content]

        try:
            llm = get_llm(active_provider, active_api_key, active_model)
        except Exception as e:
            st.error(f"Failed to initialize LLM: {e}")
            st.stop()

        prompt = ChatPromptTemplate.from_messages([
            ("system", """You are an expert code reviewer. When given a GitHub PR URL:

1. Fetch PR metadata to understand its purpose

2. Fetch the PR diff to see what changed

3. Analyze for: bugs, security issues, code quality, naming problems

4. Return structured review with this exact format for each issue:



ISSUE: [short title]

FILE: [filename]

SEVERITY: [High/Medium/Low]

PROBLEM: [what is wrong]

FIX: [how to fix it]

---



IMPORTANT: You MUST put --- on its own line between every single issue. No exceptions.



End with a SUMMARY section."""),
            ("human", "{input}"),
            MessagesPlaceholder(variable_name="agent_scratchpad")
        ])

        agent = create_tool_calling_agent(llm, tools, prompt)
        agent_executor = AgentExecutor(agent=agent, tools=tools, verbose=False, max_iterations=10)

        status_box = st.empty()
        with status_box.container():
            st.info("🤖 Agent is analyzing the PR... this may take 15–30 seconds.")

        try:
            result = agent_executor.invoke({"input": f"Review this PR: {pr_url}"})
            status_box.empty()
            output = result["output"]

            import gc
            gc.collect()

            high   = output.upper().count("SEVERITY: HIGH")
            medium = output.upper().count("SEVERITY: MEDIUM")
            low    = output.upper().count("SEVERITY: LOW")
            total  = high + medium + low

            st.markdown("### 📊 Review Summary")
            m1, m2, m3, m4 = st.columns(4)
            with m1: st.markdown(f'<div class="metric-box"><div class="metric-value" style="color:#58a6ff">{total}</div><div class="metric-label">Total Issues</div></div>', unsafe_allow_html=True)
            with m2: st.markdown(f'<div class="metric-box"><div class="metric-value" style="color:#f85149">{high}</div><div class="metric-label">High Severity</div></div>', unsafe_allow_html=True)
            with m3: st.markdown(f'<div class="metric-box"><div class="metric-value" style="color:#d29922">{medium}</div><div class="metric-label">Medium Severity</div></div>', unsafe_allow_html=True)
            with m4: st.markdown(f'<div class="metric-box"><div class="metric-value" style="color:#3fb950">{low}</div><div class="metric-label">Low Severity</div></div>', unsafe_allow_html=True)

            st.markdown("<br>", unsafe_allow_html=True)

            c1, c2 = st.columns([3, 2])
            with c1:
                if files_data:
                    st.plotly_chart(build_diff_graph(files_data), use_container_width=True)
            with c2:
                if total > 0:
                    st.plotly_chart(build_severity_chart(high, medium, low), use_container_width=True)

            if files_data:
                st.markdown("### 🗂️ File Changes")
                for f in files_data:
                    with st.expander(f"📄 {f['name']}  (+{f['additions']} / -{f['deletions']})"):
                        st.markdown(render_diff_html(f["patch"]), unsafe_allow_html=True)

            st.markdown("### 🔍 Detailed Review")
            blocks = re.split(r'---|\n(?=ISSUE:)', output)
            cards_rendered = 0
            for block in blocks:
                block = block.strip()
                if not block or "SUMMARY" in block.upper():
                    continue
                if "ISSUE:" in block.upper():
                    sev = "high" if "SEVERITY: HIGH" in block.upper() else "medium" if "SEVERITY: MEDIUM" in block.upper() else "low"
                    st.markdown(
                        f'<div class="review-card {sev}-card">'
                        f'<span class="badge badge-{sev}">{sev.upper()}</span>'
                        f'<pre style="white-space:pre-wrap;color:#e6edf3;background:transparent;border:none;padding:0;margin:0">{block}</pre>'
                        f'</div>',
                        unsafe_allow_html=True
                    )
                    cards_rendered += 1

            if cards_rendered == 0:
                st.markdown(
                    f'<div class="review-card low-card">'
                    f'<pre style="white-space:pre-wrap;color:#e6edf3;background:transparent;border:none;padding:0;margin:0">{output}</pre>'
                    f'</div>',
                    unsafe_allow_html=True
                )

            if "SUMMARY" in output.upper():
                idx = output.upper().find("SUMMARY")
                st.markdown("### 📝 Summary")
                st.markdown(
                    f'<div class="review-card" style="border-left:4px solid #58a6ff">{output[idx:]}</div>',
                    unsafe_allow_html=True
                )

        except Exception as e:
            status_box.empty()
            st.error(f"Agent error: {str(e)}")