"""Proposal System - Library Ingest Lambda.

Processes approved/sent proposals and curated pricing library items into the
Bedrock Knowledge Base library. Formats data as structured markdown and uploads
to the library bucket, then triggers a KB sync.

Supports two SQS message shapes (PR5):
  - Proposal:     {"jobType":"library-ingest","payload":{"proposalId":"<guid>"}}
  - Pricing item: {"jobType":"library-ingest","payload":{"pricingLibraryItemId":"<guid>"}}
"""

import json
import logging
import os
import re
import time
from datetime import datetime

import boto3
from botocore.auth import SigV4Auth
from botocore.awsrequest import AWSRequest
import httpx

logger = logging.getLogger(__name__)
logger.setLevel(os.environ.get("LOG_LEVEL", "INFO"))

# Fix: LAM-M8 — pattern for allowed S3 key characters
_SAFE_S3_KEY_RE = re.compile(r"^[a-zA-Z0-9\-_./\s]+$")

LIBRARY_BUCKET = os.environ.get("LIBRARY_BUCKET", "")
KNOWLEDGE_BASE_ID = os.environ.get("KNOWLEDGE_BASE_ID", "")
DATA_SOURCE_ID = os.environ.get("DATA_SOURCE_ID", "")
API_BASE_URL = os.environ.get("API_BASE_URL", "")
INTERNAL_API_KEY_SECRET_ARN = os.environ.get("INTERNAL_API_KEY_SECRET_ARN", "")

s3 = boto3.client("s3")
bedrock_agent = boto3.client("bedrock-agent")
secrets_client = boto3.client("secretsmanager")

_cached_api_key: str | None = None
_cached_api_key_ts: float = 0.0
_API_KEY_TTL_SECONDS = 300  # Fix: LAM-M9 — re-fetch every 5 minutes


def _get_api_key() -> str:
    """Fetch internal API key from Secrets Manager with a 5-minute TTL cache.

    Fix: LAM-M9 — the key was previously cached indefinitely. Now the cached
    value expires after _API_KEY_TTL_SECONDS so rotated secrets take effect.
    """
    global _cached_api_key, _cached_api_key_ts
    now = time.monotonic()
    if (
        _cached_api_key is not None
        and (now - _cached_api_key_ts) < _API_KEY_TTL_SECONDS
    ):
        return _cached_api_key
    if INTERNAL_API_KEY_SECRET_ARN:
        resp = secrets_client.get_secret_value(SecretId=INTERNAL_API_KEY_SECRET_ARN)
        _cached_api_key = resp["SecretString"]
    else:
        _cached_api_key = ""
    _cached_api_key_ts = now
    return _cached_api_key


def _validate_s3_key(key: str) -> str:
    """Fix: LAM-M8 — sanitize and validate S3 keys before use."""
    sanitized = key.replace("../", "").replace("..\\", "")
    while "//" in sanitized:
        sanitized = sanitized.replace("//", "/")
    sanitized = sanitized.strip("/").strip()

    if not sanitized:
        raise ValueError("S3 key is empty after sanitization")
    if not _SAFE_S3_KEY_RE.match(sanitized):
        raise ValueError(f"S3 key contains disallowed characters: {sanitized!r}")
    return sanitized


def handler(event, context):
    batch_item_failures = []

    # Fix: LAM-M1 — validate event structure before processing
    records = event.get("Records")
    if not isinstance(records, list) or not records:
        logger.warning("Event has no Records or Records is not a list, returning early")
        return {"batchItemFailures": []}

    for record in records:
        if "body" not in record:
            logger.warning(
                "Record missing 'body' key, skipping: %s",
                record.get("messageId", "unknown"),
            )
            continue

        try:
            body = json.loads(record["body"])
        except (json.JSONDecodeError, TypeError) as e:
            # Fix: LAM-M1 — malformed JSON cannot be retried, add to failures
            logger.error("Malformed JSON in record %s: %s", record.get("messageId"), e)
            batch_item_failures.append({"itemIdentifier": record["messageId"]})
            continue

        try:
            payload = body.get("payload", body)

            # PR5: branch on payload shape — pricing item vs proposal.
            pricing_item_id = payload.get("pricingLibraryItemId")
            proposal_id = payload.get("proposalId")
            if pricing_item_id and proposal_id:
                logger.warning(
                    "Record %s has both pricingLibraryItemId and proposalId; "
                    "treating as a pricing item",
                    record.get("messageId"),
                )
            if pricing_item_id:
                process_pricing_item_ingestion(pricing_item_id)
            elif proposal_id:
                process_ingestion(proposal_id)
            else:
                raise ValueError(
                    "library-ingest payload has neither pricingLibraryItemId nor proposalId"
                )
        except Exception as e:
            # Fix: LAM-M5 — include stack trace in error logging
            logger.exception(
                "Failed to process record %s: %s", record.get("messageId"), e
            )
            batch_item_failures.append({"itemIdentifier": record["messageId"]})
    return {"batchItemFailures": batch_item_failures}


def process_ingestion(proposal_id: str):
    proposal = fetch_proposal(proposal_id)
    if not proposal:
        logger.warning("Proposal %s not found", proposal_id)
        return

    line_items = fetch_line_items(proposal_id)

    document = format_proposal_document(proposal, line_items)

    s3_key = upload_to_library(proposal, document)

    if s3_key:
        trigger_kb_sync()


def process_pricing_item_ingestion(item_id: str):
    """PR5: Ingest a curated pricing library item into the Bedrock Knowledge Base."""
    item = fetch_pricing_item(item_id)
    if not item:
        logger.warning("Pricing library item %s not found, skipping", item_id)
        return

    document = format_pricing_item_document(item)

    s3_key = upload_pricing_item_to_library(item, document)

    if s3_key:
        trigger_kb_sync()


def fetch_pricing_item(item_id: str) -> dict | None:
    """PR5: Fetch a pricing library item from the .NET API."""
    try:
        resp = _retry_request(
            "GET",
            f"{API_BASE_URL}/api/pricing-library/{item_id}",
            headers=_api_headers(),
        )
        if resp.status_code == 200:
            return resp.json()
    except Exception as e:
        logger.exception("Error fetching pricing library item: %s", e)
    return None


def format_pricing_item_document(item: dict) -> str:
    """PR5: Format a pricing library item as a markdown document for Bedrock KB embedding."""
    unit_price = item.get("unitPrice")
    price_str = f"${unit_price:,.2f}" if unit_price is not None else "-"

    keywords = item.get("keywords") or []
    keywords_str = ", ".join(keywords) if isinstance(keywords, list) else str(keywords)

    lines = [
        f"# Pricing Item: {item.get('title', '')}",
        "",
        f"**Service Category:** {item.get('serviceCategory', '')}",
        f"**Unit:** {item.get('unit', '')}",
        f"**Unit Price:** {price_str}",
        f"**Source:** {item.get('source', '')}",
        "",
        "## Description",
        "",
        item.get("description", ""),
        "",
        "## Keywords",
        "",
        keywords_str,
    ]

    return "\n".join(lines)


def upload_pricing_item_to_library(item: dict, document: str) -> str | None:
    """PR5: Upload a formatted pricing item to the library S3 bucket.

    Uses the ``pricing-library/{category}/{item_id}.md`` key prefix so pricing
    items never collide with proposal documents stored under ``proposals/``.
    """
    if not LIBRARY_BUCKET:
        logger.warning("No library bucket configured")
        return None

    item_id = item.get("id", "unknown")
    title = item.get("title", "unknown")
    category = item.get("serviceCategory", "general")
    s3_key = f"pricing-library/{category.lower()}/{item_id}.md"

    try:
        s3_key = _validate_s3_key(s3_key)
    except ValueError as e:
        logger.error("Invalid S3 key for pricing item %s: %s", item_id, e)
        return None

    try:
        s3.put_object(
            Bucket=LIBRARY_BUCKET,
            Key=s3_key,
            Body=document.encode("utf-8"),
            ContentType="text/markdown",
            Metadata={
                "service-category": category,
                "pricing-item-title": title,
                "pricing-item-id": str(item_id),
            },
        )
        logger.info("Uploaded pricing item %s to library bucket at %s", item_id, s3_key)
        return s3_key
    except Exception as e:
        logger.exception("Error uploading pricing item to library: %s", e)
        return None


def fetch_proposal(proposal_id: str) -> dict | None:
    try:
        resp = _retry_request(
            "GET",
            f"{API_BASE_URL}/api/proposals/{proposal_id}",
            headers=_api_headers(),
        )
        if resp.status_code == 200:
            return resp.json()
    except Exception as e:
        # Fix: LAM-M5 — include stack trace in error logging
        logger.exception("Error fetching proposal: %s", e)
    return None


def fetch_line_items(proposal_id: str) -> list[dict]:
    try:
        resp = _retry_request(
            "GET",
            f"{API_BASE_URL}/api/proposals/{proposal_id}/line-items",
            headers=_api_headers(),
        )
        if resp.status_code == 200:
            return resp.json()
    except Exception as e:
        # Fix: LAM-M5 — include stack trace in error logging
        logger.exception("Error fetching line items: %s", e)
    return []


def format_proposal_document(proposal: dict, line_items: list[dict]) -> str:
    total = sum(li.get("totalPrice", 0) for li in line_items)
    submitted_at = proposal.get("submittedAt", "")
    if submitted_at:
        try:
            dt = datetime.fromisoformat(submitted_at.replace("Z", "+00:00"))
            submitted_at = dt.strftime("%Y-%m-%d")
        except (ValueError, TypeError):
            pass

    lines = [
        f"# Proposal: {proposal['proposalNumber']}",
        "",
        f"**Customer:** {proposal['customerName']}",
        f"**Address:** {proposal.get('customerAddress', '')}",
        f"**Service Category:** {proposal['serviceCategory']}",
        f"**Priority:** {proposal['priority']}",
        f"**Date:** {submitted_at}",
        f"**Total Bid Amount:** ${total:,.2f}",
        f"**Work Order:** {proposal.get('workOrderNumber', '')}",
        "",
        "## Scope of Work",
        "",
        proposal.get("refinedScope") or proposal.get("scopeOfWork", ""),
        "",
        "## Line Items",
        "",
        "| # | Description | Qty | Unit | Unit Price | Total |",
        "|---|---|---|---|---|---|",
    ]

    for i, li in enumerate(line_items, 1):
        desc = li.get("description", "")
        qty = li.get("quantity", "")
        unit = li.get("unit", "")
        unit_price = li.get("unitPrice")
        total_price = li.get("totalPrice", 0)

        up_str = f"${unit_price:,.2f}" if unit_price else "-"
        tp_str = f"${total_price:,.2f}"

        lines.append(f"| {i} | {desc} | {qty} | {unit} | {up_str} | {tp_str} |")

    lines.extend(
        [
            "",
            f"**Total: ${total:,.2f}**",
        ]
    )

    return "\n".join(lines)


def upload_to_library(proposal: dict, document: str) -> str | None:
    if not LIBRARY_BUCKET:
        logger.warning("No library bucket configured")
        return None

    proposal_number = proposal["proposalNumber"]
    category = proposal.get("serviceCategory", "General")
    s3_key = f"proposals/{category.lower()}/{proposal_number}.md"

    # Fix: LAM-M8 — validate constructed S3 key
    try:
        s3_key = _validate_s3_key(s3_key)
    except ValueError as e:
        logger.error("Invalid S3 key for proposal %s: %s", proposal_number, e)
        return None

    try:
        s3.put_object(
            Bucket=LIBRARY_BUCKET,
            Key=s3_key,
            Body=document.encode("utf-8"),
            ContentType="text/markdown",
            Metadata={
                "service-category": category,
                "proposal-number": proposal_number,
                "customer-name": proposal.get("customerName", ""),
                "total-amount": str(proposal.get("totalBidAmount", 0)),
                "date-submitted": proposal.get("submittedAt", ""),
            },
        )
        logger.info("Uploaded %s to library bucket", s3_key)
        return s3_key
    except Exception as e:
        # Fix: LAM-M5 — include stack trace in error logging
        logger.exception("Error uploading to library: %s", e)
        return None


def trigger_kb_sync():
    if not KNOWLEDGE_BASE_ID or not DATA_SOURCE_ID:
        logger.info("KB or data source ID not configured, skipping sync")
        return

    try:
        response = bedrock_agent.start_ingestion_job(
            knowledgeBaseId=KNOWLEDGE_BASE_ID,
            dataSourceId=DATA_SOURCE_ID,
        )
        job_id = response.get("ingestionJob", {}).get("ingestionJobId", "")
        logger.info("Started KB ingestion job: %s", job_id)
    except Exception as e:
        # Fix: LAM-M5 — include stack trace in error logging
        logger.exception("Error triggering KB sync: %s", e)


def _api_headers() -> dict:
    headers = {"Content-Type": "application/json"}
    api_key = _get_api_key()
    if api_key:
        headers["X-Internal-Api-Key"] = api_key
    return headers


# Fix (v1 PR1): SigV4-sign internal calls to the .NET API Function URL (authType=AWS_IAM).
# The X-Internal-Api-Key header is preserved for the application-layer check; SigV4
# satisfies the transport-layer IAM auth the Function URL enforces.
_SIGV4_SERVICE = "lambda"
_boto_session = boto3.Session()


def _sign_request_headers(method: str, url: str, body: bytes, headers: dict) -> dict:
    """Return headers with a SigV4 signature for the AWS_IAM Function URL call.

    Falls back to the unsigned headers when no AWS credentials are resolvable, so a
    non-IAM target still works in local development.
    """
    creds = _boto_session.get_credentials()
    if creds is None:
        return headers
    region = os.environ.get("AWS_REGION") or os.environ.get(
        "AWS_DEFAULT_REGION", "us-east-1"
    )
    aws_request = AWSRequest(method=method, url=url, data=body, headers=dict(headers))
    SigV4Auth(creds, _SIGV4_SERVICE, region).add_auth(aws_request)
    return dict(aws_request.headers)


def _retry_request(
    method: str, url: str, *, max_retries: int = 3, **kwargs
) -> httpx.Response:
    kwargs.setdefault("timeout", 10)
    base_headers = dict(kwargs.pop("headers", None) or {})
    # Serialize the body once so the bytes we sign are exactly the bytes we send:
    # SigV4 hashes the payload, so httpx must not re-serialize a json= kwarg.
    if "json" in kwargs:
        body = json.dumps(kwargs.pop("json")).encode("utf-8")
        base_headers.setdefault("Content-Type", "application/json")
    elif "content" in kwargs:
        raw = kwargs.pop("content")
        body = raw if isinstance(raw, bytes) else (raw or "").encode("utf-8")
    else:
        body = b""
    kwargs["content"] = body
    last_resp = None
    for attempt in range(max_retries):
        # Sign per attempt so a slow retry never sends an expired SigV4 timestamp.
        kwargs["headers"] = _sign_request_headers(method, url, body, base_headers)
        try:
            resp = httpx.request(method, url, **kwargs)
            if resp.status_code < 500:
                return resp
            last_resp = resp
        except (httpx.ConnectError, httpx.ReadTimeout, httpx.WriteTimeout) as exc:
            if attempt == max_retries - 1:
                raise
            logger.warning(
                "Retryable error (attempt %d/%d): %s", attempt + 1, max_retries, exc
            )
        time.sleep(min(2**attempt, 4))
    if last_resp is not None:
        return last_resp
    raise RuntimeError(f"All {max_retries} retries failed for {method} {url}")