import json
import os
import subprocess
import sys

import requests
import yaml
from comment import to_markdown

ROOT = os.path.dirname(__file__)
CFG = yaml.safe_load(open(f"{ROOT}/config.yml"))

# Marker to identify the AI comment
AI_MARKER = "<!-- AI_CODE_REVIEW -->"

# Disclaimer text to prepend
AI_DISCLAIMER = ""

# -------------------------------
# Helper functions
# -------------------------------


def get_diff() -> str:
    """Get git diff against main branch, limited by config"""
    diff = subprocess.check_output(["git", "diff", "origin/main...HEAD"], text=True)
    lines = diff.splitlines()
    if len(lines) > CFG["review"]["max_diff_lines"]:
        return "\n".join(lines[: CFG["review"]["max_diff_lines"]])
    return diff


def build_prompt(diff: str) -> str:
    """Prepare the AI prompt with the diff"""
    base = open(f"{ROOT}/prompts/base.md").read()
    return f"{base}\n\nDIFF:\n{diff}"


def call_llm(prompt: str) -> str:
    """Call the configured LLM provider"""
    provider = CFG["provider"]

    if provider == "openai":
        r = requests.post(
            "https://api.openai.com/v1/chat/completions",
            headers={
                "Authorization": f"Bearer {os.environ['OPENAI_API_KEY']}",
                "Content-Type": "application/json",
            },
            json={
                "model": CFG["model"]["openai"],
                "temperature": CFG["temperature"],
                "messages": [{"role": "user", "content": prompt}],
            },
            timeout=60,
        )
        return r.json()["choices"][0]["message"]["content"]

    if provider == "openrouter":
        r = requests.post(
            "https://openrouter.ai/api/v1/chat/completions",
            headers={
                "Authorization": f"Bearer {os.environ['OPENROUTER_API_KEY']}",
                "Content-Type": "application/json",
            },
            json={
                "model": CFG["model"]["openrouter"],
                "messages": [{"role": "user", "content": prompt}],
            },
            timeout=60,
        )
        return r.json()["choices"][0]["message"]["content"]

    if provider == "ollama":
        r = requests.post(
            f"{os.environ['OLLAMA_HOST']}/api/generate",
            json={
                "model": CFG["model"]["ollama"],
                "prompt": prompt,
                "stream": False,
            },
            timeout=120,
        )
        return r.json()["response"]

    raise RuntimeError("Unknown provider")


# -------------------------------
# Gitea PR comment functions
# -------------------------------


def find_existing_comment() -> int | None:
    """Find existing AI review comment in the PR"""
    url = (
        f"{os.environ['AI_REVIEW_API_URL']}/repos/"
        f"{os.environ['AI_REVIEW_REPO']}/issues/"
        f"{os.environ['AI_REVIEW_PR_NUMBER']}/comments"
    )

    r = requests.get(
        url,
        headers={"Authorization": f"token {os.environ['AI_REVIEW_TOKEN']}"},
        timeout=15,
    )

    for c in r.json():
        if AI_MARKER in c["body"]:
            return c["id"]

    return None


def upsert_pr_comment(markdown: str):
    """Create or update the PR comment"""
    comment_id = find_existing_comment()
    headers = {
        "Authorization": f"token {os.environ['AI_REVIEW_TOKEN']}",
        "Content-Type": "application/json",
    }

    if comment_id:
        url = (
            f"{os.environ['AI_REVIEW_API_URL']}/repos/"
            f"{os.environ['AI_REVIEW_REPO']}/issues/comments/{comment_id}"
        )
        r = requests.patch(url, headers=headers, json={"body": markdown})
    else:
        url = (
            f"{os.environ['AI_REVIEW_API_URL']}/repos/"
            f"{os.environ['AI_REVIEW_REPO']}/issues/"
            f"{os.environ['AI_REVIEW_PR_NUMBER']}/comments"
        )
        r = requests.post(url, headers=headers, json={"body": markdown})

    if r.status_code not in (200, 201):
        raise RuntimeError(f"Failed to upsert PR comment: {r.text}")


# -------------------------------
# Main workflow
# -------------------------------


def main():
    diff = get_diff()
    if not diff.strip():
        sys.exit(0)

    raw = call_llm(build_prompt(diff))
    result = json.loads(raw)

    # Convert JSON review to Markdown
    markdown = to_markdown(result)

    # Prepend AI disclaimer and marker
    full_comment = AI_DISCLAIMER + "\n\n" + AI_MARKER + "\n" + markdown

    upsert_pr_comment(full_comment)

    # Fail CI if severity is HIGH
    if result["overall_severity"] == CFG["review"][
        "fail_on_severity"
    ] and not result.get("approval", False):
        sys.exit(1)


if __name__ == "__main__":
    main()