"""``/tools/*`` — read-only registry view.

Two endpoints:
- ``GET /tools?category=`` — list, optionally filtered to one category.
- ``GET /tools/{name}`` — single tool detail.

Both wrap :func:`src.lib.tools.repo.load_registry`. No paid calls.
"""

from __future__ import annotations

from fastapi import APIRouter, Depends, Path, Query

from src.api.deps import forbid_readers
from src.api.dto.tools import (
    ToolCategoryEnum,
    ToolDTO,
    ToolPricingDTO,
    ToolStatusEnum,
)
from src.api.errors import ApiError
from src.lib.auth.models import User
from src.lib.llm_keys.store import KNOWN_PROVIDERS, resolve_provider_key
from src.lib.tools.models import Tool
from src.lib.tools.repo import get_tool, load_registry

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


class ToolNotFound(ApiError):
    """404 for ``GET /tools/{name}`` when the registry has no such tool.

    Local to this router — every other 404 is on the canonical list in
    ``src/api/errors.py``. We don't add this to the central module
    because the tools registry is a single YAML file and an "unknown
    tool" lookup is more of a programming error than a real user-facing
    state.
    """

    code = "TOOL_NOT_FOUND"
    status_code = 404


def _to_dto(tool: Tool) -> ToolDTO:
    pricing = None
    if tool.pricing is not None:
        # tools_registry.yaml uses YAML date literals; PyYAML parses them to
        # ``datetime.date`` objects. The wire shape is a string (ISO date) —
        # the FE renders it as-is in the "last verified" column.
        last_updated_raw = tool.pricing.last_updated
        last_updated = str(last_updated_raw) if last_updated_raw is not None else None
        pricing = ToolPricingDTO(
            input_per_million_usd=tool.pricing.input_per_million_usd,
            output_per_million_usd=tool.pricing.output_per_million_usd,
            image_input_tokens_per_image=tool.pricing.image_input_tokens_per_image,
            per_request_usd=tool.pricing.per_request_usd,
            last_updated=last_updated,
            verified=tool.pricing.verified,
        )
    # Task A1b: for llm tools, surface whether the provider's key is
    # resolvable (store or env) so the FE picker can disable unconfigured
    # providers. Only meaningful for the 5 managed LLM providers; None for
    # everything else. Never exposes the key value.
    active: bool | None = None
    if tool.category == "llm" and tool.provider in KNOWN_PROVIDERS:
        active = resolve_provider_key(tool.provider) is not None
    return ToolDTO(
        name=tool.name,
        category=ToolCategoryEnum(tool.category),
        status=ToolStatusEnum(tool.status),
        used_by=list(tool.used_by),
        compatible_with=list(tool.compatible_with),
        source_file=tool.source_file,
        provider=tool.provider,
        pricing=pricing,
        notes=tool.notes,
        active=active,
    )


@router.get("", response_model=list[ToolDTO])
def list_tools(
    _: User = Depends(forbid_readers),
    category: ToolCategoryEnum | None = Query(default=None),
) -> list[ToolDTO]:
    """All tools, optionally filtered to one category.

    Active tools sort first, then stubbed, then planned (matches the
    Operations Tools page's column order).
    """
    rank = {"active": 0, "stubbed": 1, "planned": 2}
    tools = list(load_registry())
    if category is not None:
        tools = [t for t in tools if t.category == category.value]
    tools.sort(key=lambda t: (rank[t.status], t.name))
    return [_to_dto(t) for t in tools]


@router.get("/{name}", response_model=ToolDTO)
def get_tool_endpoint(
    name: str = Path(...),
    _: User = Depends(forbid_readers),
) -> ToolDTO:
    tool = get_tool(name)
    if tool is None:
        raise ToolNotFound(f"No tool named {name!r} in tools_registry.yaml.")
    return _to_dto(tool)