# Copyright (c) 2022 Kyle Schouviller (https://github.com/kyle0654)

from typing import List, Optional, Union, Annotated
from fastapi import Query, Path, Body
from fastapi.routing import APIRouter
from fastapi.responses import Response
from pydantic.fields import Field

from ...services.item_storage import PaginatedResults
from ..dependencies import ApiDependencies
from ...invocations.baseinvocation import BaseInvocation
from ...services.graph import EdgeConnection, Graph, GraphExecutionState, NodeAlreadyExecutedError
from ...invocations import *

session_router = APIRouter(
    prefix = '/v1/sessions',
    tags = ['sessions']
)


@session_router.post('/',
    operation_id = 'create_session',
    responses = {
        200: {"model": GraphExecutionState},
        400: {'description': 'Invalid json'}
    })
async def create_session(
    graph: Optional[Graph] = Body(default = None, description = "The graph to initialize the session with")
) -> GraphExecutionState:
    """Creates a new session, optionally initializing it with an invocation graph"""
    session = ApiDependencies.invoker.create_execution_state(graph)
    return session


@session_router.get('/',
    operation_id = 'list_sessions',
    responses = {
        200: {"model": PaginatedResults[GraphExecutionState]}
    })
async def list_sessions(
    page: int     = Query(default = 0, description = "The page of results to get"),
    per_page: int = Query(default = 10, description = "The number of results per page"),
    query: str    = Query(default = '', description = "The query string to search for")
) -> PaginatedResults[GraphExecutionState]:
    """Gets a list of sessions, optionally searching"""
    if filter == '':
        result = ApiDependencies.invoker.invoker_services.graph_execution_manager.list(page, per_page)
    else:
        result = ApiDependencies.invoker.invoker_services.graph_execution_manager.search(query, page, per_page)
    return result


@session_router.get('/{session_id}',
    operation_id = 'get_session',
    responses = {
        200: {"model": GraphExecutionState},
        404: {'description': 'Session not found'}
    })
async def get_session(
    session_id: str = Path(description = "The id of the session to get")
) -> GraphExecutionState:
    """Gets a session"""
    session = ApiDependencies.invoker.invoker_services.graph_execution_manager.get(session_id)
    if session is None:
        return Response(status_code = 404)
    else:
        return session


@session_router.post('/{session_id}/nodes',
    operation_id = 'add_node',
    responses = {
        200: {"model": str},
        400: {'description': 'Invalid node or link'},
        404: {'description': 'Session not found'}
    }
)
async def add_node(
    session_id: str = Path(description = "The id of the session"),
    node: Annotated[Union[BaseInvocation.get_invocations()], Field(discriminator="type")] = Body(description = "The node to add")
) -> str:
    """Adds a node to the graph"""
    session = ApiDependencies.invoker.invoker_services.graph_execution_manager.get(session_id)
    if session is None:
        return Response(status_code = 404)

    try:
        session.add_node(node)
        ApiDependencies.invoker.invoker_services.graph_execution_manager.set(session) # TODO: can this be done automatically, or add node through an API?
        return session.id
    except NodeAlreadyExecutedError:
        return Response(status_code = 400)
    except IndexError:
        return Response(status_code = 400)
        

@session_router.put('/{session_id}/nodes/{node_path}',
    operation_id = 'update_node',
    responses = {
        200: {"model": GraphExecutionState},
        400: {'description': 'Invalid node or link'},
        404: {'description': 'Session not found'}
    }
)
async def update_node(
    session_id: str = Path(description = "The id of the session"),
    node_path: str = Path(description = "The path to the node in the graph"),
    node: Annotated[Union[BaseInvocation.get_invocations()], Field(discriminator="type")] = Body(description = "The new node")
) -> GraphExecutionState:
    """Updates a node in the graph and removes all linked edges"""
    session = ApiDependencies.invoker.invoker_services.graph_execution_manager.get(session_id)
    if session is None:
        return Response(status_code = 404)

    try:
        session.update_node(node_path, node)
        ApiDependencies.invoker.invoker_services.graph_execution_manager.set(session) # TODO: can this be done automatically, or add node through an API?
        return session
    except NodeAlreadyExecutedError:
        return Response(status_code = 400)
    except IndexError:
        return Response(status_code = 400)


@session_router.delete('/{session_id}/nodes/{node_path}',
    operation_id = 'delete_node',
    responses = {
        200: {"model": GraphExecutionState},
        400: {'description': 'Invalid node or link'},
        404: {'description': 'Session not found'}
    }
)
async def delete_node(
    session_id: str = Path(description = "The id of the session"),
    node_path: str = Path(description = "The path to the node to delete")
) -> GraphExecutionState:
    """Deletes a node in the graph and removes all linked edges"""
    session = ApiDependencies.invoker.invoker_services.graph_execution_manager.get(session_id)
    if session is None:
        return Response(status_code = 404)

    try:
        session.delete_node(node_path)
        ApiDependencies.invoker.invoker_services.graph_execution_manager.set(session) # TODO: can this be done automatically, or add node through an API?
        return session
    except NodeAlreadyExecutedError:
        return Response(status_code = 400)
    except IndexError:
        return Response(status_code = 400)


@session_router.post('/{session_id}/edges',
    operation_id = 'add_edge',
    responses = {
        200: {"model": GraphExecutionState},
        400: {'description': 'Invalid node or link'},
        404: {'description': 'Session not found'}
    }
)
async def add_edge(
    session_id: str = Path(description = "The id of the session"),
    edge: tuple[EdgeConnection, EdgeConnection] = Body(description = "The edge to add")
) -> GraphExecutionState:
    """Adds an edge to the graph"""
    session = ApiDependencies.invoker.invoker_services.graph_execution_manager.get(session_id)
    if session is None:
        return Response(status_code = 404)

    try:
        session.add_edge(edge)
        ApiDependencies.invoker.invoker_services.graph_execution_manager.set(session) # TODO: can this be done automatically, or add node through an API?
        return session
    except NodeAlreadyExecutedError:
        return Response(status_code = 400)
    except IndexError:
        return Response(status_code = 400)


# TODO: the edge being in the path here is really ugly, find a better solution
@session_router.delete('/{session_id}/edges/{from_node_id}/{from_field}/{to_node_id}/{to_field}',
    operation_id = 'delete_edge',
    responses = {
        200: {"model": GraphExecutionState},
        400: {'description': 'Invalid node or link'},
        404: {'description': 'Session not found'}
    }
)
async def delete_edge(
    session_id: str = Path(description = "The id of the session"),
    from_node_id: str = Path(description = "The id of the node the edge is coming from"),
    from_field: str = Path(description = "The field of the node the edge is coming from"),
    to_node_id: str = Path(description = "The id of the node the edge is going to"),
    to_field: str = Path(description = "The field of the node the edge is going to")
) -> GraphExecutionState:
    """Deletes an edge from the graph"""
    session = ApiDependencies.invoker.invoker_services.graph_execution_manager.get(session_id)
    if session is None:
        return Response(status_code = 404)

    try:
        edge = (EdgeConnection(node_id = from_node_id, field = from_field), EdgeConnection(node_id = to_node_id, field = to_field))
        session.delete_edge(edge)
        ApiDependencies.invoker.invoker_services.graph_execution_manager.set(session) # TODO: can this be done automatically, or add node through an API?
        return session
    except NodeAlreadyExecutedError:
        return Response(status_code = 400)
    except IndexError:
        return Response(status_code = 400)
        

@session_router.put('/{session_id}/invoke',
    operation_id = 'invoke_session',
    responses = {
        200: {"model": None},
        202: {'description': 'The invocation is queued'},
        400: {'description': 'The session has no invocations ready to invoke'},
        404: {'description': 'Session not found'}
    })
async def invoke_session(
    session_id: str = Path(description = "The id of the session to invoke"),
    all: bool       = Query(default = False, description = "Whether or not to invoke all remaining invocations")
) -> None:
    """Invokes a session"""
    session = ApiDependencies.invoker.invoker_services.graph_execution_manager.get(session_id)
    if session is None:
        return Response(status_code = 404)
    
    if session.is_complete():
        return Response(status_code = 400)
    
    ApiDependencies.invoker.invoke(session, invoke_all = all)
    return Response(status_code=202)