Resume & Cover Letter Improver: AI Feedback With STAR Bullets and ATS Keywords

# Resume & Cover Letter Improver — Streamlit + Groq
# Save as app.py, add GROQ_API_KEY to .streamlit/secrets.toml, then: streamlit run app.py

import io
import ssl

import httpx
import streamlit as st
import truststore

MAX_RESUME_CHARS = 8000
MAX_JD_CHARS = 4000

st.set_page_config(page_title="Resume & Cover Letter Improver", layout="centered")
st.title("Resume & Cover Letter Improver")
st.caption(
    "Upload or paste your resume, add a job description, and get AI-powered "
    "feedback plus a tailored cover letter."
)

_ssl_ctx = truststore.SSLContext(ssl.PROTOCOL_TLS_CLIENT)


@st.cache_resource
def _groq_client():
    import groq

    return groq.Groq(
        api_key=st.secrets["GROQ_API_KEY"],
        http_client=httpx.Client(timeout=120.0, verify=_ssl_ctx),
    )


_CHAT_MODEL = "llama-3.3-70b-versatile"


def _extract_pdf_text(uploaded_file) -> str:
    import pypdf

    reader = pypdf.PdfReader(io.BytesIO(uploaded_file.read()))
    return "\n".join(page.extract_text() or "" for page in reader.pages)


st.markdown("### Your Resume")

uploaded = st.file_uploader("Upload PDF resume", type=["pdf"])

resume_from_pdf = ""
if uploaded:
    with st.spinner("Extracting text from PDF…"):
        try:
            resume_from_pdf = _extract_pdf_text(uploaded)[:MAX_RESUME_CHARS]
            st.success(f"Extracted {len(resume_from_pdf):,} characters from PDF.")
        except Exception as err:
            st.error(f"Could not read PDF: {err}")

pasted_resume = st.text_area(
    "Or paste resume text here",
    value=resume_from_pdf,
    height=240,
    placeholder="Paste your resume content here…",
    max_chars=MAX_RESUME_CHARS,
)

final_resume = (pasted_resume or resume_from_pdf).strip()

st.markdown("### Job Description")
job_desc = st.text_area(
    "Paste the job description (required for Cover Letter; optional for Improvements)",
    height=160,
    placeholder="Copy and paste the full job listing you're applying for…",
    max_chars=MAX_JD_CHARS,
)

st.markdown("---")
col_a, col_b = st.columns(2)
with col_a:
    do_improve = st.button("Suggest Improvements", type="primary", use_container_width=True)
with col_b:
    do_cover = st.button("Generate Cover Letter", type="primary", use_container_width=True)

if do_improve or do_cover:
    if not final_resume:
        st.warning("Please upload or paste your resume first.")
    elif do_cover and not job_desc.strip():
        st.warning("Please paste a job description to generate a tailored cover letter.")
    else:
        client = _groq_client()

        if do_improve:
            with st.spinner("Analyzing your resume…"):
                try:
                    system_msg = (
                        "You are an expert resume reviewer and career coach. "
                        "Review the resume and provide exactly four sections using these headings:\n"
                        "**Strengths** — 2-3 bullets on what is done well.\n"
                        "**Improvements** — 3-5 specific, actionable fixes.\n"
                        "**Rewritten Bullet Examples** — rewrite 2 weak bullet points using the STAR method.\n"
                        "**ATS Keywords** — list 8-10 keywords missing from the resume common for this role. "
                        "Be direct and constructive. Do not add any preamble."
                    )
                    user_content = f"Resume:\n{final_resume}"
                    if job_desc.strip():
                        user_content += f"\n\nTarget job description:\n{job_desc}"
                    resp = client.chat.completions.create(
                        model=_CHAT_MODEL,
                        messages=[
                            {"role": "system", "content": system_msg},
                            {"role": "user", "content": user_content},
                        ],
                    )
                    feedback = (resp.choices[0].message.content or "").strip()
                    st.markdown("### Resume Feedback")
                    st.markdown(feedback)
                except Exception as err:
                    st.error(f"Something went wrong: {err}")

        if do_cover:
            with st.spinner("Writing your cover letter…"):
                try:
                    system_msg = (
                        "You are a professional cover letter writer. "
                        "Write a compelling, tailored cover letter based on the resume and job description. "
                        "Structure: strong opening hook, connect experience to the role's requirements, "
                        "highlight 2-3 specific achievements with numbers where possible, close with a call to action. "
                        "Keep it to 3-4 paragraphs. "
                        "Use the candidate's name from the resume if present; otherwise write in first person. "
                        "Output only the letter text — no instructions or meta commentary."
                    )
                    resp = client.chat.completions.create(
                        model=_CHAT_MODEL,
                        messages=[
                            {"role": "system", "content": system_msg},
                            {
                                "role": "user",
                                "content": (
                                    f"Resume:\n{final_resume}\n\nJob description:\n{job_desc}"
                                ),
                            },
                        ],
                    )
                    letter = (resp.choices[0].message.content or "").strip()
                    st.markdown("### Cover Letter")
                    st.markdown(letter)
                    st.download_button(
                        "Download Cover Letter (.txt)",
                        data=letter,
                        file_name="cover_letter.txt",
                        mime="text/plain",
                    )
                except Exception as err:
                    st.error(f"Something went wrong: {err}")