compaction

type Checkpoint struct {
	// TurnID is the stored turn the summary covers through, inclusive.
	TurnID  string
	Summary string
	// Degraded reports that Summary holds a raw archive because the
	// summarizer failed. It is still a checkpoint: the next compaction
	// folds it in as the previous summary.
	Degraded bool
}

type Compactor struct {
	// contains filtered or unexported fields
}

type CutPoint struct {
	// FirstKeptIdx is the index of the first message kept verbatim.
	FirstKeptIdx int
	// TurnStartIdx is the user message that opened the turn the cut lands in,
	// or -1 when the cut falls on a turn boundary.
	TurnStartIdx int
	// IsSplitTurn reports that the cut divides a single turn, so the part
	// before it needs its own summary to explain the part after it.
	IsSplitTurn bool
}

type Preparation struct {
	// FirstKeptIdx is where the verbatim tail begins.
	FirstKeptIdx int
	// MessagesToSummarize are the complete turns being replaced by prose.
	MessagesToSummarize []chat.Message
	// TurnPrefixMessages is the discarded head of a split turn, summarized
	// separately so the retained tail still has its originating request.
	TurnPrefixMessages []chat.Message
	IsSplitTurn        bool
	// PreviousSummary is the prior compaction's text, updated in place rather
	// than summarized again.
	PreviousSummary string
	TokensBefore    int
	// OmittedHistory and OmittedTurnPrefix count the oldest messages of each
	// range left out because one summarization request could not carry them
	// (see fitSummarizerInput). Their file paths are still recorded.
	OmittedHistory    int
	OmittedTurnPrefix int
	// contains filtered or unexported fields
}

type Reason string

type Result struct {
	Messages       []chat.Message
	Summary        string
	Reason         Reason
	TokensBefore   int
	TokensAfter    int
	MessagesBefore int
	MessagesAfter  int
	// Degraded reports that at least one summary came from the raw archive
	// because the summarizer failed. The context still shrank; its memory is
	// just coarser.
	Degraded bool
	// SplitTurn reports that the cut divided a single turn, so a turn-prefix
	// summary was generated alongside the history summary.
	SplitTurn bool
	// Checkpoint is the part of this compaction a later turn can start from,
	// or nil when there is none (see Preparation.checkpoint).
	Checkpoint *Checkpoint
	// Omitted counts the oldest messages left out of the summarization
	// requests because they did not fit (see fitSummarizerInput).
	Omitted int
}

type Settings struct {
	// Enabled turns automatic compaction on. Disabled still allows an
	// explicit overflow-recovery compaction, which is a repair, not a policy.
	Enabled bool
	// MaxContextTokens is the model's context window. Zero disables
	// compaction entirely: without a window there is no budget to enforce.
	MaxContextTokens int
	// ReserveTokens is the part of the window history may not occupy because
	// the next response has to fit there.
	ReserveTokens int
	// KeepRecentTokens is the token budget of recent messages kept verbatim.
	KeepRecentTokens int
	// MaxSummaryTokens caps the summarization completion. Zero falls back to
	// the reserve-derived budget alone.
	MaxSummaryTokens int
	// StallTimeout is how long a summarization stream may produce no output
	// before it is cancelled. Zero means DefaultSummarizationStallTimeout.
	StallTimeout time.Duration
}