from __future__ import annotations

from dataclasses import dataclass
from urllib.parse import urlencode


@dataclass(frozen=True)
class TaskToolDefinition:
    code: str
    name: str
    description: str
    launch_url: str | None = None


_TASK_TOOLS: tuple[TaskToolDefinition, ...] = (
    TaskToolDefinition(code="NONE", name="None", description="Normal task workflow without an attached ERP tool."),
    TaskToolDefinition(
        code="ACCOUNTING_OPENING_BALANCE",
        name="Opening Balance Review",
        description="Launch the existing Tally opening-balance comparison and verification tool.",
        launch_url="/tools/accounting/opening-balances",
    ),
    TaskToolDefinition(
        code="ACCOUNTING_BANK_RECONCILIATION",
        name="Bank Reconciliation",
        description="Launch the existing accounting bank-reconciliation workspace.",
        launch_url="/tools/accounting/bank-reconciliation",
    ),
    TaskToolDefinition(
        code="ACCOUNTING_DEPRECIATION_IT",
        name="Depreciation (IT)",
        description="Launch the existing Income-tax depreciation workspace connected to Tally.",
        launch_url="/tools/tally/depreciation",
    ),    TaskToolDefinition(
        code="ACCOUNTING_CASH_PAYMENT_COMPLIANCE",
        name="Cash Payment Tax Compliance Review",
        description="Review Tally cash payments against the configurable limit, same-day aggregation and possible split-payment patterns.",
        launch_url="/tools/accounting/cash-payments",
    ),
    TaskToolDefinition(
        code="ACCOUNTING_TDS_COMPLIANCE",
        name="TDS Compliance Review",
        description="Review expenses, purchases, capital purchases and creditor transactions in Tally for TDS applicability, threshold crossing and short/non-deduction.",
        launch_url="/tools/accounting/tds/compliance",
    ),
    TaskToolDefinition(
        code="ACCOUNTING_TDS_RECONCILIATION",
        name="TDS Reconciliation",
        description="Compare Tally TDS liability with return/form, challan and TRACES data.",
        launch_url="/tools/accounting/tds/reconciliation",
    ),

)


def list_task_tools() -> list[TaskToolDefinition]:
    return list(_TASK_TOOLS)


def get_task_tool(code: str | None) -> TaskToolDefinition:
    normalized = normalize_task_tool_code(code)
    for tool in _TASK_TOOLS:
        if tool.code == normalized:
            return tool
    return _TASK_TOOLS[0]


def normalize_task_tool_code(code: str | None) -> str:
    value = (code or "NONE").strip().upper() or "NONE"
    valid = {tool.code for tool in _TASK_TOOLS}
    if value not in valid:
        raise ValueError(f"Unsupported task tool: {value}")
    return value


def build_task_tool_launch_url(
    tool: TaskToolDefinition,
    *,
    client_id: int,
    task_id: int,
    tool_run_id: int,
) -> str:
    if not tool.launch_url:
        raise ValueError("This ERP task tool does not expose a launch URL.")
    query = urlencode(
        {
            "client_id": int(client_id),
            "task_id": int(task_id),
            "task_tool_run_id": int(tool_run_id),
            "task_return_url": f"/services/work-tracker/tasks/{int(task_id)}/edit",
            "task_result_url": f"/services/work-tracker/tool-runs/{int(tool_run_id)}/result",
        }
    )
    separator = "&" if "?" in tool.launch_url else "?"
    return f"{tool.launch_url}{separator}{query}"