"""FastAPI REST API for activity-core.

T30: CRUD for ActivityDefinition + manual one-shot trigger.

Endpoints:
  GET    /activity-definitions/          — list all
  GET    /activity-definitions/{id}      — get one
  POST   /activity-definitions/          — create
  PUT    /activity-definitions/{id}      — update
  DELETE /activity-definitions/{id}      — delete
  POST   /activity-definitions/{id}/trigger — manual one-shot run

Schedule lifecycle:
  - POST/PUT with trigger_type='cron' upserts a Temporal Schedule.
  - DELETE removes the Temporal Schedule if present.
  - /trigger starts RunActivityWorkflow directly (works for any trigger_type).

Run with:
    TEMPORAL_HOST=localhost:7233 \
    ACTCORE_DB_URL=postgresql+asyncpg://actcore:actcore@localhost:5433/actcore \
        uv run uvicorn activity_core.api:app --port 8010
"""

from __future__ import annotations

import os
import uuid
from contextlib import asynccontextmanager
from datetime import datetime, timezone
from typing import Any

from fastapi import FastAPI, HTTPException
from pydantic import BaseModel
from sqlalchemy import select
from sqlalchemy.ext.asyncio import AsyncSession, async_sessionmaker, create_async_engine
from temporalio.client import Client

from activity_core.models import ActivityDefinition, CronTriggerConfig
from activity_core.orm import ActivityDefinition as ActivityDefinitionRow
from activity_core.schedule_manager import delete_schedule, upsert_schedule

TEMPORAL_HOST = os.environ.get("TEMPORAL_HOST", "localhost:7233")
TEMPORAL_NAMESPACE = os.environ.get("TEMPORAL_NAMESPACE", "default")
_ORCHESTRATOR_TASK_QUEUE = "orchestrator-tq"

# --- App state ---------------------------------------------------------------

_session_factory: async_sessionmaker[AsyncSession] | None = None
_temporal_client: Client | None = None


@asynccontextmanager
async def lifespan(app: FastAPI):  # type: ignore[type-arg]
    global _session_factory, _temporal_client

    db_url = os.environ.get("ACTCORE_DB_URL")
    if not db_url:
        raise RuntimeError("ACTCORE_DB_URL is required")

    engine = create_async_engine(db_url)
    _session_factory = async_sessionmaker(engine, expire_on_commit=False)
    _temporal_client = await Client.connect(TEMPORAL_HOST, namespace=TEMPORAL_NAMESPACE)

    yield

    await engine.dispose()


app = FastAPI(title="activity-core API", lifespan=lifespan)


def _get_db() -> async_sessionmaker[AsyncSession]:
    assert _session_factory is not None
    return _session_factory


def _get_temporal() -> Client:
    assert _temporal_client is not None
    return _temporal_client


# --- Schemas -----------------------------------------------------------------

class ActivityDefinitionCreate(BaseModel):
    name: str
    enabled: bool = True
    trigger_config: dict[str, Any]
    context_sources: list[dict[str, Any]] = []
    task_templates: list[dict[str, Any]] = []
    dedupe_key_strategy: str = "skip"
    version: int = 1


class ActivityDefinitionUpdate(BaseModel):
    name: str | None = None
    enabled: bool | None = None
    trigger_config: dict[str, Any] | None = None
    context_sources: list[dict[str, Any]] | None = None
    task_templates: list[dict[str, Any]] | None = None
    dedupe_key_strategy: str | None = None
    version: int | None = None


class ActivityDefinitionResponse(BaseModel):
    id: uuid.UUID
    name: str
    enabled: bool
    trigger_type: str
    trigger_config: dict[str, Any]
    context_sources: list[dict[str, Any]]
    task_templates: list[dict[str, Any]]
    dedupe_key_strategy: str
    version: int
    created_at: datetime
    updated_at: datetime


def _row_to_response(row: ActivityDefinitionRow) -> ActivityDefinitionResponse:
    return ActivityDefinitionResponse(
        id=row.id,
        name=row.name,
        enabled=row.enabled,
        trigger_type=row.trigger_type,
        trigger_config=row.trigger_config,
        context_sources=row.context_sources,
        task_templates=row.task_templates,
        dedupe_key_strategy=row.dedupe_key_strategy,
        version=row.version,
        created_at=row.created_at,
        updated_at=row.updated_at,
    )


async def _upsert_schedule_if_cron(row: ActivityDefinitionRow) -> None:
    """Upsert a Temporal Schedule for the row if it uses a cron trigger."""
    try:
        defn = ActivityDefinition.model_validate(
            {
                "id": row.id,
                "name": row.name,
                "enabled": row.enabled,
                "trigger_config": row.trigger_config,
                "context_sources": row.context_sources,
                "task_templates": row.task_templates,
                "dedupe_key_strategy": row.dedupe_key_strategy,
                "version": row.version,
            }
        )
        if isinstance(defn.trigger_config, CronTriggerConfig):
            await upsert_schedule(_get_temporal(), defn)
    except Exception:
        pass  # Schedule management is best-effort; don't fail the API call.


# --- Routes ------------------------------------------------------------------

@app.get("/activity-definitions/", response_model=list[ActivityDefinitionResponse])
async def list_definitions() -> list[ActivityDefinitionResponse]:
    """List all ActivityDefinitions."""
    Session = _get_db()
    async with Session() as session:
        rows = (await session.scalars(select(ActivityDefinitionRow))).all()
    return [_row_to_response(r) for r in rows]


@app.get("/activity-definitions/{definition_id}", response_model=ActivityDefinitionResponse)
async def get_definition(definition_id: uuid.UUID) -> ActivityDefinitionResponse:
    """Get one ActivityDefinition by ID."""
    Session = _get_db()
    async with Session() as session:
        row = await session.get(ActivityDefinitionRow, definition_id)
    if row is None:
        raise HTTPException(status_code=404, detail="ActivityDefinition not found")
    return _row_to_response(row)


@app.post("/activity-definitions/", response_model=ActivityDefinitionResponse, status_code=201)
async def create_definition(body: ActivityDefinitionCreate) -> ActivityDefinitionResponse:
    """Create a new ActivityDefinition. Upserts a Temporal Schedule if trigger_type='cron'."""
    trigger_type = body.trigger_config.get("trigger_type", "")
    row = ActivityDefinitionRow(
        id=uuid.uuid4(),
        name=body.name,
        enabled=body.enabled,
        trigger_type=trigger_type,
        trigger_config=body.trigger_config,
        context_sources=body.context_sources,
        task_templates=body.task_templates,
        dedupe_key_strategy=body.dedupe_key_strategy,
        version=body.version,
    )
    Session = _get_db()
    async with Session() as session:
        async with session.begin():
            session.add(row)
    await _upsert_schedule_if_cron(row)
    return _row_to_response(row)


@app.put("/activity-definitions/{definition_id}", response_model=ActivityDefinitionResponse)
async def update_definition(
    definition_id: uuid.UUID, body: ActivityDefinitionUpdate
) -> ActivityDefinitionResponse:
    """Update an ActivityDefinition. Re-upserts the Temporal Schedule if trigger_type='cron'."""
    Session = _get_db()
    async with Session() as session:
        row = await session.get(ActivityDefinitionRow, definition_id)
        if row is None:
            raise HTTPException(status_code=404, detail="ActivityDefinition not found")

        if body.name is not None:
            row.name = body.name
        if body.enabled is not None:
            row.enabled = body.enabled
        if body.trigger_config is not None:
            row.trigger_config = body.trigger_config
            row.trigger_type = body.trigger_config.get("trigger_type", row.trigger_type)
        if body.context_sources is not None:
            row.context_sources = body.context_sources
        if body.task_templates is not None:
            row.task_templates = body.task_templates
        if body.dedupe_key_strategy is not None:
            row.dedupe_key_strategy = body.dedupe_key_strategy
        if body.version is not None:
            row.version = body.version

        async with session.begin():
            session.add(row)

    await _upsert_schedule_if_cron(row)
    return _row_to_response(row)


@app.delete("/activity-definitions/{definition_id}", status_code=204)
async def delete_definition(definition_id: uuid.UUID) -> None:
    """Delete an ActivityDefinition and its Temporal Schedule if present."""
    Session = _get_db()
    async with Session() as session:
        row = await session.get(ActivityDefinitionRow, definition_id)
        if row is None:
            raise HTTPException(status_code=404, detail="ActivityDefinition not found")
        async with session.begin():
            await session.delete(row)

    await delete_schedule(_get_temporal(), definition_id)


@app.post("/activity-definitions/{definition_id}/trigger", status_code=202)
async def trigger_definition(definition_id: uuid.UUID) -> dict[str, str]:
    """Manually trigger a one-shot RunActivityWorkflow for any ActivityDefinition."""
    Session = _get_db()
    async with Session() as session:
        row = await session.get(ActivityDefinitionRow, definition_id)
    if row is None:
        raise HTTPException(status_code=404, detail="ActivityDefinition not found")

    trigger_key = f"manual-{uuid.uuid4()}"
    workflow_id = f"activity-{definition_id}:{trigger_key}"

    handle = await _get_temporal().start_workflow(
        "RunActivityWorkflow",
        args=[str(definition_id), trigger_key, datetime.now(tz=timezone.utc).isoformat()],
        id=workflow_id,
        task_queue=_ORCHESTRATOR_TASK_QUEUE,
    )
    return {"workflow_id": handle.id, "trigger_key": trigger_key}