"""Execution plan API — AP1.16b."""

from __future__ import annotations

from typing import Literal, Optional

from capabilities import require_capability
from fastapi import APIRouter, Depends, HTTPException, Query
from pydantic import BaseModel
from services import actions as action_service
from services import execution_plan as execution_plan_service
from steering.graph.execution_engine import load_initiative_execution_graph_state
from tenant_context import TenantContext

initiative_router = APIRouter(prefix="/api/initiatives", tags=["execution-plan"])


class ActionDependencyCreateRequest(BaseModel):
    predecessor_action_id: str
    successor_action_id: str
    dependency_kind: Literal["requires", "blocks", "relates"] = "requires"


@initiative_router.get("/{initiative_id}/execution/graph-state")
def get_initiative_execution_graph_state(
    initiative_id: str,
    scope_roadmap_item_id: Optional[str] = Query(default=None),
    ctx: TenantContext = Depends(require_capability("kairo.action.read")),
):
    try:
        state = load_initiative_execution_graph_state(
            tenant_id=ctx.tenant_id,
            initiative_id=initiative_id,
            scope_roadmap_item_id=scope_roadmap_item_id,
        )
        if scope_roadmap_item_id is None:
            from services import actions as action_service
            from services import roadmap as roadmap_service

            all_actions = action_service.list_actions_for_initiative(
                tenant_id=ctx.tenant_id, initiative_id=initiative_id
            )
            roadmap_items = roadmap_service.list_roadmap_items_for_initiative(
                tenant_id=ctx.tenant_id, initiative_id=initiative_id
            )
            from steering.graph.execution_engine import compute_planning_debt

            state["planning_debt"] = compute_planning_debt(
                actions=all_actions,
                roadmap_items=roadmap_items,
            )
        return state
    except ValueError as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc


@initiative_router.get("/{initiative_id}/execution/dependencies")
def list_initiative_action_dependencies(
    initiative_id: str,
    ctx: TenantContext = Depends(require_capability("kairo.action.read")),
):
    try:
        return execution_plan_service.list_dependencies_for_initiative(
            tenant_id=ctx.tenant_id, initiative_id=initiative_id
        )
    except ValueError as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc


@initiative_router.post("/{initiative_id}/execution/dependencies", status_code=201)
def create_initiative_action_dependency(
    initiative_id: str,
    body: ActionDependencyCreateRequest,
    ctx: TenantContext = Depends(require_capability("kairo.action.manage")),
):
    try:
        predecessor = action_service.get_action(
            tenant_id=ctx.tenant_id, action_id=body.predecessor_action_id
        )
        successor = action_service.get_action(
            tenant_id=ctx.tenant_id, action_id=body.successor_action_id
        )
        if not predecessor or not successor:
            raise ValueError("Action nicht gefunden")
        if (
            predecessor["initiative_id"] != initiative_id
            or successor["initiative_id"] != initiative_id
        ):
            raise ValueError("Actions gehören nicht zum angegebenen Vorhaben")

        return execution_plan_service.add_dependency(
            tenant_id=ctx.tenant_id,
            predecessor_action_id=body.predecessor_action_id,
            successor_action_id=body.successor_action_id,
            dependency_kind=body.dependency_kind,
            user_id=ctx.user_id,
        )
    except ValueError as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc


@initiative_router.delete(
    "/{initiative_id}/execution/dependencies/{dependency_id}",
    status_code=204,
)
def delete_initiative_action_dependency(
    initiative_id: str,
    dependency_id: str,
    ctx: TenantContext = Depends(require_capability("kairo.action.manage")),
):
    del initiative_id  # scope validated via tenant + dependency row
    try:
        execution_plan_service.delete_dependency(
            tenant_id=ctx.tenant_id,
            dependency_id=dependency_id,
            user_id=ctx.user_id,
        )
    except ValueError as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc