"""BacklogItem API — AP0.8c."""

from __future__ import annotations

from typing import Literal, Optional

from capabilities import require_capability
from fastapi import APIRouter, Depends, HTTPException
from pydantic import BaseModel, Field
from services import backlog as backlog_service
from tenant_context import TenantContext

router = APIRouter(prefix="/api/backlog", tags=["backlog"])


class BacklogCreateRequest(BaseModel):
    title: str = Field(min_length=1, max_length=255)
    description: str = ""
    status: Literal["new", "triaged", "accepted", "rejected"] = "new"
    priority: Literal["low", "normal", "high"] = "normal"
    roadmap_item_id: Optional[str] = None
    sort_order: Optional[int] = None


class BacklogUpdateRequest(BaseModel):
    title: Optional[str] = Field(default=None, min_length=1, max_length=255)
    description: Optional[str] = None
    status: Optional[Literal["new", "triaged", "accepted", "rejected"]] = None
    priority: Optional[Literal["low", "normal", "high"]] = None
    roadmap_item_id: Optional[str] = None
    clear_roadmap_item: bool = False
    sort_order: Optional[int] = None


class BacklogConvertRequest(BaseModel):
    assigned_actor_ids: list[str] = Field(default_factory=list)
    work_cycle_id: Optional[str] = None
    assign_active_sprint: bool = True


@router.get("/{backlog_item_id}")
def get_backlog_item(
    backlog_item_id: str,
    ctx: TenantContext = Depends(require_capability("kairo.backlog.read")),
):
    item = backlog_service.get_backlog_item(
        tenant_id=ctx.tenant_id, backlog_item_id=backlog_item_id
    )
    if not item:
        raise HTTPException(status_code=404, detail="Backlog-Item nicht gefunden")
    return item


@router.patch("/{backlog_item_id}")
def update_backlog_item(
    backlog_item_id: str,
    body: BacklogUpdateRequest,
    ctx: TenantContext = Depends(require_capability("kairo.backlog.manage")),
):
    try:
        item = backlog_service.update_backlog_item(
            tenant_id=ctx.tenant_id,
            backlog_item_id=backlog_item_id,
            user_id=ctx.user_id,
            title=body.title,
            description=body.description,
            status=body.status,
            priority=body.priority,
            roadmap_item_id=body.roadmap_item_id,
            clear_roadmap_item=body.clear_roadmap_item,
            sort_order=body.sort_order,
        )
    except ValueError as exc:
        raise HTTPException(status_code=400, detail=str(exc)) from exc
    if not item:
        raise HTTPException(status_code=404, detail="Backlog-Item nicht gefunden")
    return item


@router.delete("/{backlog_item_id}", status_code=204)
def delete_backlog_item(
    backlog_item_id: str,
    ctx: TenantContext = Depends(require_capability("kairo.backlog.manage")),
):
    if not backlog_service.delete_backlog_item(
        tenant_id=ctx.tenant_id,
        backlog_item_id=backlog_item_id,
        user_id=ctx.user_id,
    ):
        raise HTTPException(status_code=404, detail="Backlog-Item nicht gefunden")


@router.post("/{backlog_item_id}/convert-to-action", status_code=201)
def convert_backlog_to_action(
    backlog_item_id: str,
    body: BacklogConvertRequest,
    ctx: TenantContext = Depends(require_capability("kairo.backlog.manage")),
):
    assigned = body.assigned_actor_ids
    if not assigned and ctx.actor_id:
        assigned = [ctx.actor_id]
    try:
        return backlog_service.convert_backlog_to_action(
            tenant_id=ctx.tenant_id,
            backlog_item_id=backlog_item_id,
            user_id=ctx.user_id,
            assigned_actor_ids=assigned,
            work_cycle_id=body.work_cycle_id,
            assign_active_sprint=body.assign_active_sprint,
        )
    except ValueError as exc:
        detail = str(exc)
        if detail == "Backlog-Item nicht gefunden":
            raise HTTPException(status_code=404, detail=detail) from exc
        raise HTTPException(status_code=400, detail=detail) from exc