#!/usr/bin/env python3
"""l3b_agent_stub.py — D-008 / D-026 / D-021

Parses a GitHub/Gitea Issue body by keywords and emits a contract.yaml that
selects an L2 stack. This is the agentic (L3B) entry surface: deterministic
keyword matching, no external AI APIs.

D-008 keyword map (priority order — first match wins):
  gas, price, ingest, data-lake        -> l2-commodity-price-feed
  invoice, billing                     -> l2-invoice-service
  analytics, historical, query         -> l2-energy-analytics-api
  regulatory, compliance, reporting, trading
                                       -> l2-regulatory-reporting
  (no match)                           -> l2-invoice-service  (fallback)

Output contract.yaml (D-021 schema):
  stack: <mapped L2 name>
  inputs:
    environment: dev
    owner: citizen-developer
    source: l3b-agent-stub
  public-ingress: false

Input:
  argv[1] = issue body text (or stdin if argv[1] absent/empty)
  -o <path> = write the contract to a file (default: stdout)
Exit:
  0 on success, 1 on empty input
"""
import sys


# Ordered keyword groups -> L2 stack mapping (D-008). First match wins.
KEYWORD_MAP = [
    (("gas", "price", "ingest", "data-lake"), "l2-commodity-price-feed"),
    (("invoice", "billing"), "l2-invoice-service"),
    (("analytics", "historical", "query"), "l2-energy-analytics-api"),
    (("regulatory", "compliance", "reporting", "trading"), "l2-regulatory-reporting"),
]

FALLBACK_STACK = "l2-invoice-service"


def map_issue_to_stack(text: str) -> str:
    lowered = text.lower()
    for keywords, stack in KEYWORD_MAP:
        for kw in keywords:
            if kw in lowered:
                return stack
    return FALLBACK_STACK


def render_contract(stack: str) -> str:
    # Fixed-schema YAML (D-021). Emitted as text (no yaml dependency needed).
    return (
        f"stack: {stack}\n"
        "inputs:\n"
        "  environment: dev\n"
        "  owner: citizen-developer\n"
        "  source: l3b-agent-stub\n"
        "public-ingress: false\n"
    )


def read_issue_body(args: list) -> str:
    """Read issue body from args[0] (already-stripped argv, no script name)
    or stdin. Empty -> error."""
    if len(args) >= 1 and args[0].strip():
        return args[0]
    # Fall back to stdin if argv body is absent or empty.
    if not sys.stdin.isatty():
        data = sys.stdin.read()
        if data.strip():
            return data
    return ""


def parse_output_flag(argv: list):
    """Extract -o <path> from argv (returns (rest, output_path))."""
    output_path = None
    rest = []
    i = 1
    while i < len(argv):
        arg = argv[i]
        if arg == "-o":
            if i + 1 < len(argv):
                output_path = argv[i + 1]
                i += 2
                continue
            else:
                print("l3b_agent_stub: -o requires a path argument", file=sys.stderr)
                sys.exit(1)
        rest.append(arg)
        i += 1
    return rest, output_path


def main() -> int:
    rest, output_path = parse_output_flag(sys.argv)
    body = read_issue_body(rest)
    if not body.strip():
        print("l3b_agent_stub: empty issue body (no argv[1] and no stdin)", file=sys.stderr)
        return 1

    stack = map_issue_to_stack(body)
    contract = render_contract(stack)

    if output_path:
        with open(output_path, "w", encoding="utf-8") as fh:
            fh.write(contract)
    else:
        sys.stdout.write(contract)

    return 0


if __name__ == "__main__":
    sys.exit(main())