package agent

import (
	"context"

	"ollie/backend"
)

// ResultTier classifies how long a tool result stays in the hot message list.
type ResultTier int

const (
	TierHot  ResultTier = iota // stays verbatim in messages (default)
	TierWarm                   // summarized on next compaction pass
	TierCold                   // immediately summarized at update time
)

// toolResult holds the output of a single tool call.
type toolResult struct {
	ToolCallID    string // may be empty (Ollama does not always set this)
	Name          string
	Content       string
	ContentBlocks []backend.ContentBlock // image blocks extracted from tool output
	IsError       bool
	Tier          ResultTier // default TierHot; tools may self-classify
}

// state is the interface both ephemeral and bead-backed state must satisfy.
// The loop reads from it on Observe, writes to it on Update.
type state interface {
	// History returns the full conversation history for the current session.
	// The first entry is always the initial user message containing the goal.
	history() []backend.Message

	// taskState returns the current structured task state, or nil if not set.
	taskState() *TaskState

	// updateTaskState replaces the current task state.
	updateTaskState(ts TaskState)

	// Update appends the assistant's reply and any tool results to the history.
	// Called once per loop iteration after Act completes.
	update(assistant backend.Message, results []toolResult)

	// estimateTokens returns a rough token count of the current history.
	estimateTokens() int

	// stripCold summarizes large tool-result messages outside the hot tail to reduce context size.
	stripCold(ctx context.Context, b backend.Backend)
}