"""Shared offline test helpers for the procurement-ingest suite.

A real package (``tests.support``) resolved as a PEP-420 namespace member via
the repo-root conftest's sys.path insert. ``tests/`` itself gets NO __init__.py
(adding it would change pytest's module naming for the root suite).

This module imports NO moto, mutates NO environment, and imports NO handler at
module level -- the moto-before-handler ordering authority stays solely with the
repo-root conftest. The loader (which does exec handlers) is only invoked lazily
by ``load_email`` / by the pipeline shims, never at ``__init__`` import time.
"""

import io
import json
from decimal import Decimal

from tests.support.loader import REPO_ROOT, load_lambda_module

__all__ = [
    "REPO_ROOT",
    "load_lambda_module",
    "FIXTURE_DIRS",
    "stems",
    "load_raw",
    "load_email",
    "load_golden",
    "FakeTable",
    "FakeDynamoResource",
    "FakeS3",
]

FIXTURE_DIRS = {
    "po": REPO_ROOT / "lambdas/po/email_processor/tests/fixtures",
    "wo": REPO_ROOT / "lambdas/wo/email_processor/tests/fixtures",
}


def stems(pipeline, subdir):
    """Sorted list of fixture stems in ``<pipeline>/fixtures/<subdir>/*.eml``."""
    return sorted(p.stem for p in (FIXTURE_DIRS[pipeline] / subdir).glob("*.eml"))


def load_raw(pipeline, subdir, stem):
    """Raw bytes of a fixture .eml."""
    return (FIXTURE_DIRS[pipeline] / subdir / f"{stem}.eml").read_bytes()


def load_email(pipeline, subdir, stem):
    """Parse a fixture .eml into the email_data dict the parser consumes.

    Uses the Phase-3 single-sourced ``email_parsing.parse_raw_email`` that BOTH
    handlers re-export -- semantics identical to the old
    ``po_handler.parse_raw_email`` / bare ``from handler import parse_raw_email``
    paths, now with one implementation.
    """
    email_parsing = load_lambda_module("shared", "email_parsing")
    return email_parsing.parse_raw_email(load_raw(pipeline, subdir, stem))


def load_golden(pipeline, stem):
    """Load the expected parser output for a positive fixture.

    Goldens store money as JSON numbers; ``parse_float=Decimal`` mirrors the
    handler's Bedrock decode and makes every golden money value compare exactly
    equal to the parser's Decimal output (2-dp values at PO magnitudes round-trip
    float repr losslessly). Applied UNCONDITIONALLY: WO goldens are integer-only
    at the JSON-number level (verified: zero float-typed values across all 55 WO
    goldens; decimal-looking strings occur only inside comment_text STRING
    values, which parse_float never touches), so WO callers gain Decimal decoding
    with no observable change.
    """
    path = FIXTURE_DIRS[pipeline] / "expected" / f"{stem}.json"
    with open(path) as fh:
        return json.load(fh, parse_float=Decimal)


class FakeTable:
    """Superset offline DynamoDB table -- union of the PO and WO fakes.

    PO callers only ever ``update_item`` (their ``puts``/``store`` stay
    permanently empty); WO callers use ``put_item`` (recorded in ``puts`` and in
    the keyed single-row ``store``) AND ``update_item``. Neither suite regresses:
    each sees exactly the recorder it used before.
    """

    def __init__(self, name):
        self.name = name
        self.puts = []
        self.updates = []
        # Single-row-per-key store (WO): detects overwrite vs distinct rows.
        self.store = {}

    def put_item(self, Item=None, **kwargs):  # noqa: N803 (boto3 kwarg name)
        self.puts.append(Item)
        key = (Item.get("work_order_id"), Item.get("comment_id"))
        self.store[key] = Item

    def update_item(self, **kwargs):
        self.updates.append(kwargs)


class FakeDynamoResource:
    def __init__(self):
        self.tables = {}

    def Table(self, name):  # noqa: N802 (boto3 method name)
        return self.tables.setdefault(name, FakeTable(name))


class FakeS3:
    """Offline S3 client for the handler-level seam tests.

    The sender-auth gate sits AFTER ``get_object`` in both handlers, so a fake
    S3 is mandatory to reach (and exercise) the gate. ``objects`` maps the S3
    object Key to its raw bytes.
    """

    def __init__(self, objects):
        self.objects = dict(objects)

    def get_object(self, Bucket, Key):  # noqa: N803 (boto3 kwarg names)
        return {"Body": io.BytesIO(self.objects[Key])}