"""
Typed models for the Invoice Exception Handler OpenEnv environment.

Every object the agent sees or produces is defined here as a Pydantic model.
This is the single source of truth for the data contract between the
environment simulation and the agent.
"""
from __future__ import annotations

import time
from enum import Enum
from typing import Any, Dict, List, Optional

from pydantic import BaseModel, Field


# ---------------------------------------------------------------------------
# Enumerations
# ---------------------------------------------------------------------------

class ActionType(str, Enum):
    """The nine action types an agent can take during an episode."""
    INSPECT_FIELD  = "inspect_field"
    CROSS_CHECK    = "cross_check"
    RUN_CHECK      = "run_check"
    QUERY_SUPPLIER = "query_supplier"
    QUERY_INTERNAL = "query_internal"
    APPLY_RULE     = "apply_rule"
    MAKE_DECISION  = "make_decision"
    ROUTE_TO       = "route_to"
    CLOSE_CASE     = "close_case"


class DecisionType(str, Enum):
    """Possible decisions the agent can make on a flagged invoice."""
    APPROVE         = "approve"
    REJECT          = "reject"
    HOLD            = "hold"
    PARTIAL_APPROVE = "partial_approve"


class CaseStatus(str, Enum):
    """Lifecycle status of an invoice exception case."""
    OPEN      = "open"
    IN_REVIEW = "in_review"
    DECIDED   = "decided"
    ROUTED    = "routed"
    CLOSED    = "closed"


# ---------------------------------------------------------------------------
# Document models — read-only context given to the agent
# ---------------------------------------------------------------------------

class LineItem(BaseModel):
    """One line on an invoice or purchase order."""
    description: str = Field(..., description="Item description")
    quantity: int = Field(..., description="Number of units")
    unit_price: float = Field(..., description="Price per unit in INR")
    total: float = Field(..., description="Line total in INR (quantity × unit_price)")
    tax_rate: Optional[float] = Field(None, description="Tax rate as a percentage, if applicable")


class PurchaseOrder(BaseModel):
    """What was agreed to be purchased."""
    po_number: str = Field(..., description="Unique PO identifier")
    vendor_name: str = Field(..., description="Supplier name on the PO")
    po_date: str = Field(..., description="Date the PO was raised (YYYY-MM-DD)")
    line_items: List[LineItem] = Field(default_factory=list, description="Items on the PO")
    total_amount: float = Field(..., description="Total PO value in INR")
    payment_terms: str = Field("Net-30", description="Payment terms")
    currency: str = Field("INR", description="Currency code")


class Invoice(BaseModel):
    """What the supplier is claiming — the document under exception review."""
    invoice_number: str = Field(..., description="Unique invoice identifier")
    supplier_name: str = Field(..., description="Supplier name on the invoice")
    invoice_date: str = Field(..., description="Date of the invoice (YYYY-MM-DD)")
    due_date: str = Field(..., description="Payment due date (YYYY-MM-DD)")
    po_reference: str = Field(..., description="PO number referenced by this invoice")
    line_items: List[LineItem] = Field(default_factory=list, description="Items invoiced")
    subtotal: float = Field(..., description="Pre-tax total in INR")
    tax_amount: float = Field(..., description="Total tax amount in INR")
    tax_rate: float = Field(..., description="Applied tax rate as a percentage")
    total_amount: float = Field(..., description="Grand total including tax in INR")
    bank_account: str = Field(..., description="Supplier bank account on the invoice")
    bank_name: str = Field("", description="Bank name")
    ifsc_code: str = Field("", description="IFSC / routing code")
    supplier_gstin: str = Field("", description="GST Identification Number on the invoice")
    supplier_email: str = Field("", description="Email address on the invoice")
    currency: str = Field("INR", description="Currency code")


class GoodsReceiptNote(BaseModel):
    """What actually arrived at the warehouse (or service confirmation)."""
    grn_number: str = Field(..., description="Unique GRN identifier")
    po_reference: str = Field(..., description="PO number this receipt is against")
    receipt_date: str = Field(..., description="Date goods/services were received (YYYY-MM-DD)")
    items_received: List[Dict[str, Any]] = Field(
        default_factory=list,
        description="List of received item dicts with description, quantity_received, quantity_pending, quantity_rejected"
    )
    receiving_officer: str = Field("", description="Person who signed the receipt")
    notes: str = Field("", description="Any delivery notes or discrepancies observed")


class SupplierMaster(BaseModel):
    """The verified, registered supplier record in the company's ERP system."""
    supplier_id: str = Field(..., description="Internal supplier code")
    supplier_name: str = Field(..., description="Registered legal name")
    registered_address: str = Field("", description="Registered business address")
    gstin: str = Field(..., description="Verified GST Identification Number")
    bank_account: str = Field(..., description="Verified bank account number")
    bank_name: str = Field("", description="Bank name")
    ifsc_code: str = Field("", description="Verified IFSC / routing code")
    contact_email: str = Field("", description="Registered email address")
    contact_phone: str = Field("", description="Registered phone number")
    registered_domain: str = Field("", description="Verified email domain for the supplier")
    pan_number: str = Field("", description="PAN (tax ID)")
    status: str = Field("active", description="Supplier status: active, suspended, blacklisted")


class ExceptionFlag(BaseModel):
    """Why the AP system flagged this invoice for manual review."""
    flag_code: str = Field(..., description="Machine-readable code, e.g. PRICE_MISMATCH")
    flag_description: str = Field(..., description="Human-readable explanation of the flag")
    auto_hold: bool = Field(False, description="Whether the system placed an automatic payment hold")
    flagged_date: str = Field("", description="Date the flag was raised (YYYY-MM-DD)")
    severity: str = Field("medium", description="low / medium / high / critical")


# ---------------------------------------------------------------------------
# Action model
# ---------------------------------------------------------------------------

class Action(BaseModel):
    """
    An action the agent wants to take.

    Use the classmethod constructors for convenience:
        Action.run_check("tolerance_rule")
        Action.make_decision("approve", "reason here")
    """
    type: ActionType = Field(..., description="Which action type to execute")
    params: Dict[str, Any] = Field(default_factory=dict, description="Parameters for the action")

    # --- Classmethod constructors for each action type ---

    @classmethod
    def inspect_field(cls, document: str, field: str) -> Action:
        """Look at a specific field in a document."""
        return cls(type=ActionType.INSPECT_FIELD, params={"document": document, "field": field})

    @classmethod
    def cross_check(cls, field: str, doc_a: str, doc_b: str) -> Action:
        """Compare a field between two documents."""
        return cls(type=ActionType.CROSS_CHECK, params={"field": field, "doc_a": doc_a, "doc_b": doc_b})

    @classmethod
    def run_check(cls, check_name: str) -> Action:
        """Run a named validation check."""
        return cls(type=ActionType.RUN_CHECK, params={"check_name": check_name})

    @classmethod
    def query_supplier(cls, question: str, channel: str = "email") -> Action:
        """Ask the supplier a question via a specific channel."""
        return cls(type=ActionType.QUERY_SUPPLIER, params={"question": question, "channel": channel})

    @classmethod
    def query_internal(cls, department: str, question: str) -> Action:
        """Ask an internal department a question."""
        return cls(type=ActionType.QUERY_INTERNAL, params={"department": department, "question": question})

    @classmethod
    def apply_rule(cls, rule_id: str) -> Action:
        """Apply a named business policy rule."""
        return cls(type=ActionType.APPLY_RULE, params={"rule_id": rule_id})

    @classmethod
    def make_decision(cls, decision: str, reason: str) -> Action:
        """Make a case decision with a documented reason."""
        return cls(type=ActionType.MAKE_DECISION, params={"decision": decision, "reason": reason})

    @classmethod
    def route_to(cls, team: str, notes: str = "") -> Action:
        """Escalate the case to a specific team."""
        return cls(type=ActionType.ROUTE_TO, params={"team": team, "notes": notes})

    @classmethod
    def close_case(cls, summary: str) -> Action:
        """Close the case with an audit trail summary."""
        return cls(type=ActionType.CLOSE_CASE, params={"summary": summary})


# ---------------------------------------------------------------------------
# Result models — returned by simulators
# ---------------------------------------------------------------------------

class InspectionResult(BaseModel):
    """What came back from inspecting a specific field in a document."""
    document: str = Field(..., description="Which document was inspected")
    field: str = Field(..., description="Which field was inspected")
    value: Any = Field(..., description="The value found in that field")
    note: str = Field("", description="Any contextual note about the value")
    timestamp: float = Field(default_factory=time.time, description="When the inspection happened")


class CheckResult(BaseModel):
    """What came back from running a validation check or cross-check."""
    check_name: str = Field(..., description="Name of the check that was run")
    passed: bool = Field(..., description="Whether the check passed (True) or failed (False)")
    detail: str = Field("", description="Human-readable detail of what was found")
    timestamp: float = Field(default_factory=time.time, description="When the check was run")


class QueryResult(BaseModel):
    """What came back from querying a supplier or internal department."""
    target: str = Field(..., description="Who was queried (supplier, procurement, finance, etc.)")
    question: str = Field("", description="The question that was asked")
    response: str = Field(..., description="The response received")
    channel: str = Field("email", description="Communication channel used (email, phone, etc.)")
    timestamp: float = Field(default_factory=time.time, description="When the query was made")


# ---------------------------------------------------------------------------
# State models
# ---------------------------------------------------------------------------

class EnvironmentState(BaseModel):
    """
    The full observable state returned by reset() and step().

    This is what the agent sees at every turn — all documents, all history,
    and all available actions/checks/rules for the current task.
    """
    task_id: str = Field(..., description="Which task is currently running")
    step_number: int = Field(0, description="Current step number in the episode")
    case_status: CaseStatus = Field(CaseStatus.OPEN, description="Current lifecycle status")

    # The five documents
    purchase_order: PurchaseOrder = Field(..., description="The purchase order")
    invoice: Invoice = Field(..., description="The invoice under review")
    grn: GoodsReceiptNote = Field(..., description="The goods receipt note")
    supplier_master: SupplierMaster = Field(..., description="The verified supplier record")
    exception_flag: ExceptionFlag = Field(..., description="Why this invoice was flagged")

    # Agent history — what has been done so far
    inspections: List[InspectionResult] = Field(default_factory=list, description="Fields inspected")
    checks_run: List[CheckResult] = Field(default_factory=list, description="Checks completed")
    queries: List[QueryResult] = Field(default_factory=list, description="Queries made")
    rules_applied: List[str] = Field(default_factory=list, description="Rules applied")

    # Decision state
    decision: Optional[str] = Field(None, description="Current decision if one has been made")
    decision_reason: Optional[str] = Field(None, description="Reason for the decision")
    routed_to: List[str] = Field(default_factory=list, description="Teams case has been routed to")
    case_closed: bool = Field(False, description="Whether the case has been closed")
    close_summary: Optional[str] = Field(None, description="Closure summary if case is closed")

    # Action hints — what the agent can do
    available_actions: List[str] = Field(default_factory=list, description="All valid action types")
    available_checks: List[str] = Field(default_factory=list, description="Check names for this task")
    available_rules: List[str] = Field(default_factory=list, description="Rule IDs for this task")
    knowledge_base: List[str] = Field(default_factory=list, description="Policy entries for this task")

    # Running totals
    cumulative_reward: float = Field(0.0, description="Sum of all rewards received so far")


class StepResult(BaseModel):
    """What step() returns — the observation, reward, done flag, and info dict."""
    observation: EnvironmentState = Field(..., description="Updated environment state after the action")
    reward: float = Field(..., description="Reward for this specific action")
    done: bool = Field(False, description="Whether the episode is over")
    info: Dict[str, Any] = Field(default_factory=dict, description="Extra info about the step")