"""
Invoice validation orchestrator.

Loads platform_configs.json once, runs all seven validators in SDD order,
wires outputs to downstream inputs, and returns a single consolidated result.

No business logic lives here — all decisions remain inside the validator modules.
"""

import importlib.util
import json
import os


# ---------------------------------------------------------------------------
# Module loader — handles filenames that contain spaces or hyphens
# ---------------------------------------------------------------------------

def _load_fn(filename, fn_name):
    """Import a function from a .py file by path."""
    here = os.path.dirname(os.path.abspath(__file__))
    path = os.path.join(here, filename)
    spec = importlib.util.spec_from_file_location(filename, path)
    mod = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(mod)
    return getattr(mod, fn_name)


_run_vendor_validation        = _load_fn("Vendor Validation.py",         "run_vendor_validation")
_run_tax_id_validation        = _load_fn("Tax - ID validation.py",        "run_tax_id_validation")
_run_bank_validation          = _load_fn("Bank validation.py",            "run_bank_validation")
_run_date_sanity_checks       = _load_fn("date_sanity.py",                "run_date_sanity_checks")
_run_payment_terms_validation = _load_fn("payment terms valdiation.py",   "run_payment_terms_validation")
_run_tax_amount_validation    = _load_fn("tax validation.py",             "run_tax_amount_validation")
_run_completeness_validation  = _load_fn("completeness.py",               "run_invoice_validation")


# ---------------------------------------------------------------------------
# Helpers
# ---------------------------------------------------------------------------

class _FieldProxy:
    """
    Overlays computed attributes onto an existing extracted_fields object so
    downstream validators can read Tax-ID results via the normal
    getattr(extracted_fields, ...) pattern without mutating the original object.

    Only non-None values are overlaid; None values fall through to the base
    object (and its getattr default), which preserves the lenient defaults each
    validator defines for fields it cannot always receive.
    """
    __slots__ = ("_base", "_overlay")

    def __init__(self, base, **overlay):
        object.__setattr__(self, "_base", base)
        object.__setattr__(self, "_overlay", {k: v for k, v in overlay.items() if v is not None})

    def __getattr__(self, name):
        overlay = object.__getattribute__(self, "_overlay")
        if name in overlay:
            return overlay[name]
        return getattr(object.__getattribute__(self, "_base"), name)


def _load_platform_configs(path=None):
    if path is None:
        here = os.path.dirname(os.path.abspath(__file__))
        path = os.path.join(here, "platform_configs.json")
    with open(path, encoding="utf-8") as fh:
        return json.load(fh)


def _collect(result, key):
    """Safely pull a list from a module result dict (returns [] if absent)."""
    return result.get(key) or []


# ---------------------------------------------------------------------------
# Pipeline
# ---------------------------------------------------------------------------

def run_invoice_validation_pipeline(
    *,
    document,
    extracted_fields,
    vendors,
    vendor_bank_accounts,
    vendor_tax_ids,
    entity,
    line_items,
    purchase_orders,
    contracts,
    tax_master_rows,
    currency_seed_map,
    platform_configs=None,
    route_contexts=None,
    actor_id=None,
):
    """
    Run all seven validation modules in SDD order and return a consolidated result.

    Parameters
    ----------
    document              : Invoice document object (needs .id, .tenant_id, .entity_id).
    extracted_fields      : VLM-extracted fields object.
    vendors               : Iterable of vendor records used for vendor matching.
    vendor_bank_accounts  : Iterable of vendor bank account records.
    vendor_tax_ids        : Iterable of vendor tax-ID records.
    entity                : The routing entity object (needs .country_code, .vat_id, .region_code).
    line_items            : Iterable of line-item records.
    purchase_orders       : Iterable of purchase-order records.
    contracts             : Iterable of contract records.
    tax_master_rows       : Iterable of tax-master records.
    currency_seed_map     : Dict mapping ISO currency code → row with minor_unit_value.
    platform_configs      : Pre-loaded config dict; loaded from platform_configs.json when None.
    route_contexts        : List of route-context strings forwarded to Vendor Validation.
    actor_id              : Actor identifier forwarded to Vendor Validation for audit.

    Returns
    -------
    {
        "risk_flags":         [...],  # aggregated, in execution order
        "advisory_flags":     [...],  # aggregated, in execution order
        "skipped_steps":      [...],  # aggregated, in execution order
        "ops_alerts":         [...],  # operational alerts (e.g. tax_master_unconfigured)
        "resolved_vendor_id": ...,
        "module_results":     {...},  # raw return dict from each module, keyed by name
    }
    """

    if platform_configs is None:
        platform_configs = _load_platform_configs()

    risk_flags     = []
    advisory_flags = []
    skipped_steps  = []
    ops_alerts     = []
    module_results = {}

    # ------------------------------------------------------------------
    # Step 1 — Vendor Validation
    # Runs first; produces resolved_vendor_id used by all downstream steps.
    # ------------------------------------------------------------------
    vendor_result = _run_vendor_validation(
        document=document,
        extracted_fields=extracted_fields,
        vendors=vendors,
        platform_configs=platform_configs,
        route_contexts=route_contexts,
        actor_id=actor_id,
    )
    module_results["vendor_validation"] = vendor_result
    risk_flags.extend(_collect(vendor_result, "risk_flags"))
    advisory_flags.extend(_collect(vendor_result, "advisory_flags"))
    skipped_steps.extend(_collect(vendor_result, "skipped_steps"))

    resolved_vendor_id = vendor_result.get("resolved_vendor_id")

    # Resolve the vendor object so downstream modules receive it directly.
    resolved_vendor = next(
        (v for v in vendors if getattr(v, "id", None) == resolved_vendor_id),
        None,
    ) if resolved_vendor_id else None

    # ------------------------------------------------------------------
    # Step 2 — Tax ID Validation
    # Depends on resolved_vendor_id and the resolved vendor object.
    # ------------------------------------------------------------------
    tax_id_result = _run_tax_id_validation(
        document=document,
        extracted_fields=extracted_fields,
        vendor=resolved_vendor,
        vendor_tax_ids=vendor_tax_ids,
        resolved_vendor_id=resolved_vendor_id,
        platform_configs=platform_configs,
    )
    module_results["tax_id_validation"] = tax_id_result
    risk_flags.extend(_collect(tax_id_result, "risk_flags"))
    advisory_flags.extend(_collect(tax_id_result, "advisory_flags"))
    skipped_steps.extend(_collect(tax_id_result, "skipped_steps"))

    # Enrich extracted_fields with Tax-ID results so Tax Validation can read
    # sender_tax_id_inferred_family / _format_valid / _checksum_valid via its
    # normal getattr(extracted_fields, ...) pattern.
    enriched_fields = _FieldProxy(
        extracted_fields,
        sender_tax_id_inferred_family=tax_id_result.get("invoice_tax_id_inferred_type"),
        sender_tax_id_format_valid=tax_id_result.get("invoice_tax_id_format_valid"),
        sender_tax_id_checksum_valid=tax_id_result.get("invoice_tax_id_checksum_valid"),
    )

    # ------------------------------------------------------------------
    # Step 3 — Bank Validation
    # Depends on resolved_vendor_id.
    # ------------------------------------------------------------------
    bank_result = _run_bank_validation(
        document=document,
        extracted_fields=extracted_fields,
        vendor_bank_accounts=vendor_bank_accounts,
        resolved_vendor_id=resolved_vendor_id,
        platform_configs=platform_configs,
    )
    module_results["bank_validation"] = bank_result
    risk_flags.extend(_collect(bank_result, "risk_flags"))
    advisory_flags.extend(_collect(bank_result, "advisory_flags"))
    skipped_steps.extend(_collect(bank_result, "skipped_steps"))

    # ------------------------------------------------------------------
    # Step 4 — Date Sanity Checks
    # Independent of vendor resolution.
    # ------------------------------------------------------------------
    date_result = _run_date_sanity_checks(
        document=document,
        extracted_fields=extracted_fields,
        platform_configs=platform_configs,
    )
    module_results["date_sanity"] = date_result
    risk_flags.extend(_collect(date_result, "risk_flags"))
    advisory_flags.extend(_collect(date_result, "advisory_flags"))
    skipped_steps.extend(_collect(date_result, "skipped_steps"))

    # ------------------------------------------------------------------
    # Step 5 — Payment Terms Validation
    # Depends on resolved_vendor_id and the resolved vendor object.
    # ------------------------------------------------------------------
    payment_terms_result = _run_payment_terms_validation(
        document=document,
        extracted_fields=extracted_fields,
        vendor=resolved_vendor,
        purchase_orders=purchase_orders,
        contracts=contracts,
        resolved_vendor_id=resolved_vendor_id,
        platform_configs=platform_configs,
    )
    module_results["payment_terms_validation"] = payment_terms_result
    risk_flags.extend(_collect(payment_terms_result, "risk_flags"))
    advisory_flags.extend(_collect(payment_terms_result, "advisory_flags"))
    skipped_steps.extend(_collect(payment_terms_result, "skipped_steps"))

    # ------------------------------------------------------------------
    # Step 6 — Tax Amount Validation
    # Depends on resolved vendor object and enriched_fields from Step 2.
    # ------------------------------------------------------------------
    tax_result = _run_tax_amount_validation(
        document=document,
        extracted_fields=enriched_fields,
        line_items=line_items,
        vendor=resolved_vendor,
        entity=entity,
        tax_master_rows=tax_master_rows,
        platform_configs=platform_configs,
    )
    module_results["tax_validation"] = tax_result
    risk_flags.extend(_collect(tax_result, "risk_flags"))
    advisory_flags.extend(_collect(tax_result, "advisory_flags"))
    skipped_steps.extend(_collect(tax_result, "skipped_steps"))
    ops_alerts.extend(_collect(tax_result, "ops_alerts"))

    # ------------------------------------------------------------------
    # Step 7 — Completeness / Math Cross-check
    # Independent of vendor resolution.
    # ------------------------------------------------------------------
    completeness_result = _run_completeness_validation(
        document=document,
        extracted_fields=extracted_fields,
        line_items=line_items,
        currency_seed_map=currency_seed_map,
        platform_configs=platform_configs,
    )
    module_results["completeness"] = completeness_result
    risk_flags.extend(_collect(completeness_result, "risk_flags"))
    advisory_flags.extend(_collect(completeness_result, "advisory_flags"))
    skipped_steps.extend(_collect(completeness_result, "skipped_steps"))

    return {
        "risk_flags": risk_flags,
        "advisory_flags": advisory_flags,
        "skipped_steps": skipped_steps,
        "ops_alerts": ops_alerts,
        "resolved_vendor_id": resolved_vendor_id,
        "module_results": module_results,
    }