package service

import (
	"context"

	"gitea.stevedudenhoeffer.com/steve/pansy/internal/domain"
)

// Chat persistence for the garden assistant (#56). The run loop itself lives in
// internal/agent; this is the part that needs pansy's permission checks.

// maxRetainedTurns caps how much of a thread is kept in context. Retained turns
// are a working memory, not an archive — a season of chat replayed into every
// prompt would cost more than it informs.
const maxRetainedTurns = 20

// AgentHistory returns the recent messages of the actor's own thread for a
// garden they can edit, oldest first.
//
// Requires EDITOR, not viewer: the assistant acts, so being able to talk to it
// about a garden is the same permission as being able to change it. A viewer
// asking it to plant something would get a refusal from every tool anyway, and
// offering the conversation would be offering something that cannot work.
func (s *Service) AgentHistory(ctx context.Context, actorID, gardenID int64) ([]domain.AgentMessage, error) {
	if _, err := s.requireGardenRole(ctx, actorID, gardenID, roleEditor); err != nil {
		return nil, err
	}
	conv, err := s.store.EnsureConversation(ctx, gardenID, actorID)
	if err != nil {
		return nil, err
	}
	return s.store.ListAgentMessages(ctx, conv, maxRetainedTurns*2)
}

// RecordAgentExchange stores one user message and the assistant's reply, and
// returns the reply row. Called by the runtime after a turn completes.
func (s *Service) RecordAgentExchange(ctx context.Context, actorID, gardenID int64, userMessage, reply string, changeSetID *int64) (*domain.AgentMessage, error) {
	if _, err := s.requireGardenRole(ctx, actorID, gardenID, roleEditor); err != nil {
		return nil, err
	}
	conv, err := s.store.EnsureConversation(ctx, gardenID, actorID)
	if err != nil {
		return nil, err
	}
	if _, err := s.store.AppendAgentMessage(ctx, &domain.AgentMessage{
		ConversationID: conv, Role: domain.AgentRoleUser, Body: userMessage,
	}); err != nil {
		return nil, err
	}
	return s.store.AppendAgentMessage(ctx, &domain.AgentMessage{
		ConversationID: conv, Role: domain.AgentRoleAssistant, Body: reply, ChangeSetID: changeSetID,
	})
}

// ClearAgentHistory drops the actor's thread for a garden — the "start over"
// escape hatch when a conversation has gone somewhere unhelpful.
func (s *Service) ClearAgentHistory(ctx context.Context, actorID, gardenID int64) error {
	if _, err := s.requireGardenRole(ctx, actorID, gardenID, roleEditor); err != nil {
		return err
	}
	return s.store.DeleteConversation(ctx, gardenID, actorID)
}