jobhunt-platform/apps/api/app/llm.py

"""LLM gateway integration.

Per the task spec: LLM usage via packages.llm_gateway. Since T2 hasn't built
the gateway yet, this module provides a minimal mock-mode interface that the
API endpoints call. When packages.llm_gateway is available (importable), it
delegates to the real gateway. Otherwise, it returns deterministic canned
outputs per task name.

Task names used by the API:
- cv_assist: returns suggestions for a CV section bullet
- cl_critique: returns critique comments for a cover letter
"""

from __future__ import annotations

import hashlib
import json
import os
import time
from typing import Any

# Try to import the real llm_gateway package
try:
    from packages.llm_gateway.client import run_task as _real_run_task  # type: ignore
    HAS_REAL_GATEWAY = True
except Exception:
    HAS_REAL_GATEWAY = False


def _has_api_key() -> bool:
    return bool(
        os.environ.get("LLM_PRIMARY_KEY")
        or os.environ.get("OLLAMA_API_KEY")
    )


# Deterministic mock outputs per task name
MOCK_OUTPUTS: dict[str, dict[str, Any]] = {
    "cv_assist": {
        "suggestions": [
            "Improved bullet: Led cross-functional team of 8 to deliver feature X 2 weeks ahead of schedule.",
            "Alternative: Streamlined process reducing cycle time by 30% via automation.",
        ]
    },
    "cl_critique": {
        "comments": [
            {
                "quote": "I am writing to apply",
                "suggestion": "Consider a stronger opening that references the specific role.",
                "severity": "medium",
            },
            {
                "quote": "I have experience",
                "suggestion": "Quantify with a specific achievement rather than a generic claim.",
                "severity": "low",
            },
        ]
    },
    "score": {
        "score": 72,
        "rationale": {
            "match": 0.72,
            "factors": {"skills": 0.8, "location": 0.6, "experience": 0.75},
        },
        "red_flags": [],
    },
    "cv_extract": {
        "drafts": [
            {
                "kind": "experience",
                "title": "Software Engineer",
                "org": "Extracted Company",
                "location": "Malmo",
                "start_date": "2020-01",
                "end_date": None,
                "bullets": ["Developed web applications", "Led team of 3"],
                "tags": ["python", "javascript"],
            },
            {
                "kind": "education",
                "title": "MSc Computer Science",
                "org": "Lund University",
                "location": "Lund",
                "start_date": "2016-09",
                "end_date": "2018-06",
                "bullets": ["Specialized in distributed systems"],
                "tags": ["algorithms", "distributed systems"],
            },
        ]
    },
    "interview_prep": {
        "content": (
            "# Interview Prep\n\n"
            "## Q1: Tell us about yourself\n"
            "**Suggested angle:** Highlight your experience with Python and FastAPI, "
            "and your ability to deliver features on time.\n\n"
            "## Q2: Why are you interested in this role?\n"
            "**Suggested angle:** Reference the specific technologies mentioned in the "
            "posting and your experience with similar stacks.\n\n"
            "## Q3: Describe a challenging project\n"
            "**Suggested angle:** Use the STAR method. Reference your experience building "
            "distributed systems at Lund University.\n\n"
            "## Q4: How do you handle tight deadlines?\n"
            "**Suggested angle:** Mention your track record of delivering 2 weeks ahead "
            "of schedule and your automation-first approach.\n\n"
            "## Q5: What are your salary expectations?\n"
            "**Suggested angle:** Research market rates for the Skane region. "
            "Be prepared to give a range.\n\n"
            "## Q6: Tell us about a time you failed\n"
            "**Suggested angle:** Pick something real but not catastrophic. Show what "
            "you learned and how you changed your approach.\n\n"
            "## Q7: How do you stay current with technology?\n"
            "**Suggested angle:** Mention your tags: python, javascript, distributed "
            "systems. Talk about hands-on side projects.\n\n"
            "## Q8: Describe your ideal work environment\n"
            "**Suggested angle:** Be honest but flexible. Mention collaboration and "
            "autonomy.\n\n"
            "## Q9: What questions do you have for us?\n"
            "**Suggested angle:** Ask about team structure, current projects, and "
            "growth opportunities.\n\n"
            "## Q10: Why should we hire you?\n"
            "**Suggested angle:** Summarize your top 3 qualifications matching the "
            "posting requirements. Be specific."
        ),
    },
    "email_classify": {
        "classification": "interview_invite",
        "state_proposal": "interviewing",
        "reason": "The email mentions an interview invitation.",
    },
    "cv_tailor": {
        "tailored_cv": {
            "summary": "Senior Python Developer with 6+ years building scalable backend systems.",
            "skills": [
                "Python",
                "Fast API",
                "PostgreSQL",
                "Docker",
                "Kubernetes",
                "AWS",
            ],
            "experience": [
                {
                    "company": "TechCorp",
                    "role": "Senior Backend Engineer",
                    "bullets": [
                        "Led migration of monolith to microservices using Fast API",
                        "Reduced API latency by 40% through query optimization and caching",
                    ],
                },
            ],
        },
        "change_log": [
            {"action": "reordered", "detail": "Moved Python and Fast API to top of skills"},
            {"action": "rephrased", "detail": "Rewrote first experience bullet to emphasize Fast API"},
        ],
    },
    "deadline_extract": {
        "apply_by": None,
    },
}


def run_task(
    task: str,
    prompt: str,
    schema: dict[str, Any] | None = None,
    telemetry_sink: callable | None = None,
) -> dict[str, Any]:
    """Run an LLM task. Uses mock mode when no API key is present.

    Returns a dict with the task result. If a telemetry_sink callable is
    provided, it is called with a dict of token/cost info.
    """
    if HAS_REAL_GATEWAY and _has_api_key():
        return _real_run_task(task, prompt, schema)

    # Mock mode
    time.sleep(0.01)  # simulate latency
    result = MOCK_OUTPUTS.get(task, {"result": "mock"})

    # Validate against schema if provided (basic check)
    # In real gateway this would be jsonschema validation

    if telemetry_sink is not None:
        telemetry_sink({
            "task": task,
            "model": "mock",
            "provider": "mock",
            "input_tokens": len(prompt) // 4,  # rough estimate
            "output_tokens": len(json.dumps(result)) // 4,
            "cost_usd": 0.0,
            "duration_ms": 10,
        })

    return result