from core_domain import InitialNodeContract, WorkflowVersionContract
from core_dsl import (
    EdgeDefinition,
    get_initial_node_definition,
    get_node_definition,
    parse_workflow_definition,
)
from core_shared import JSONValue

from .context import build_template_context, evaluate_condition_expression


def derive_initial_node(workflow_version: WorkflowVersionContract) -> InitialNodeContract | None:
    workflow = parse_workflow_definition(workflow_version.dsl_json)
    if workflow is None:
        return None

    node = get_initial_node_definition(workflow)
    if node is None:
        return None
    return InitialNodeContract(node_id=node.id, node_type=node.type, status="queued")


def derive_successor_nodes(
    workflow_version: WorkflowVersionContract,
    current_node_id: str,
    current_output_json: dict[str, JSONValue] | None = None,
    run_state_json: dict[str, JSONValue] | None = None,
    node_output_json_by_node_id: dict[str, dict[str, JSONValue]] | None = None,
    node_output_text_by_node_id: dict[str, str] | None = None,
) -> list[InitialNodeContract]:
    workflow = parse_workflow_definition(workflow_version.dsl_json)
    if workflow is None:
        return []

    node_map = {node.id: node for node in workflow.nodes}
    template_context = build_template_context(
        node_id=current_node_id,
        node_type=node_map.get(current_node_id).type if current_node_id in node_map else "unknown",
        run_state_json=run_state_json or {},
        node_output_json_by_node_id=node_output_json_by_node_id or {},
        node_output_text_by_node_id=node_output_text_by_node_id or {},
    )
    edge_context: dict[str, JSONValue] = {
        **template_context,
        "output": current_output_json or {},
        "route": _read_string_value(current_output_json or {}, "route"),
        "condition_result": _read_bool_value(current_output_json or {}, "condition_result"),
    }

    successors: list[InitialNodeContract] = []
    for edge in _get_matching_edges(
        workflow.edges,
        current_node_id=current_node_id,
        edge_context=edge_context,
    ):
        successor = node_map.get(edge.target)
        if successor is None:
            continue
        successors.append(
            InitialNodeContract(
                node_id=successor.id,
                node_type=successor.type,
                status="queued",
            )
        )
    return successors


def derive_node_config(
    workflow_version: WorkflowVersionContract,
    node_id: str,
) -> dict[str, JSONValue]:
    workflow = parse_workflow_definition(workflow_version.dsl_json)
    if workflow is None:
        return {}

    node = get_node_definition(workflow, node_id)
    if node is None:
        return {}
    return dict(node.config)


def _get_matching_edges(
    edges: list[EdgeDefinition],
    *,
    current_node_id: str,
    edge_context: dict[str, JSONValue],
) -> list[EdgeDefinition]:
    matching_edges: list[EdgeDefinition] = []
    for edge in edges:
        if edge.source != current_node_id:
            continue
        if _matches_edge_condition(edge.condition, edge_context):
            matching_edges.append(edge)
    return matching_edges


def _matches_edge_condition(
    condition: str | None,
    context: dict[str, JSONValue],
) -> bool:
    if condition is None or not condition.strip():
        return True

    stripped = condition.strip()
    route = context.get("route")
    if isinstance(route, str) and stripped == route:
        return True

    condition_result = context.get("condition_result")
    if isinstance(condition_result, bool) and stripped.lower() in {"true", "false"}:
        return condition_result is (stripped.lower() == "true")

    return evaluate_condition_expression(stripped, context)


def _read_string_value(payload: dict[str, JSONValue], key: str) -> str | None:
    value = payload.get(key)
    if isinstance(value, str):
        return value
    return None


def _read_bool_value(payload: dict[str, JSONValue], key: str) -> bool | None:
    value = payload.get(key)
    if isinstance(value, bool):
        return value
    return None