harn-stdlib 0.8.25

import { agent_record_compaction } from "std/agent/state"

fn __compaction_strategy_label(value) {
  if type_of(value) == "string" {
    return value
  }
  if type_of(value) == "dict" {
    let label = value?.strategy ?? value?.kind ?? value?.type
    if type_of(label) == "string" && label != "" {
      return label
    }
    return "hybrid"
  }
  return ""
}

fn __compaction_engine_strategy(label) {
  if label == "truncate" {
    return "truncate"
  }
  if label == "summarize_all" || label == "summarize_middle" || label == "summarize"
    || label == "hybrid"
    || label == "llm" {
    return "llm"
  }
  if label == "observation_mask" {
    return "observation_mask"
  }
  return "observation_mask"
}

fn __compaction_keep_last(opts) {
  let cfg = opts?.compaction
  if type_of(cfg) == "dict" {
    let keep = cfg?.keep_last_n ?? cfg?.keep_last
    if type_of(keep) == "int" {
      return keep
    }
  }
  if type_of(opts?.compact_keep_last) == "int" {
    return opts.compact_keep_last
  }
  return nil
}

fn __compact_options(opts, engine_strategy, keep_last) {
  let auto_cfg = opts?.auto_compact
  var compact_opts = if type_of(auto_cfg) == "dict" {
    auto_cfg
  } else {
    {}
  }
  if !contains(compact_opts.keys(), "compact_threshold") && opts?.compact_threshold != nil {
    compact_opts = compact_opts + {compact_threshold: opts.compact_threshold}
  }
  if !contains(compact_opts.keys(), "keep_last") && keep_last != nil {
    compact_opts = compact_opts + {keep_last: keep_last}
  }
  if !contains(compact_opts.keys(), "compact_strategy") {
    if opts?.compact_strategy != nil {
      compact_opts = compact_opts + {compact_strategy: opts.compact_strategy}
    } else if engine_strategy != "" {
      compact_opts = compact_opts + {compact_strategy: engine_strategy}
    }
  }
  if !contains(compact_opts.keys(), "compact_callback") && opts?.compact_callback != nil {
    compact_opts = compact_opts + {compact_callback: opts.compact_callback}
  }
  if !contains(compact_opts.keys(), "provider") && opts?.provider != nil {
    compact_opts = compact_opts + {provider: opts.provider}
  }
  if !contains(compact_opts.keys(), "model") && opts?.model != nil {
    compact_opts = compact_opts + {model: opts.model}
  }
  return compact_opts
}

fn __auto_compact_summary(before, after) {
  if len(after) == 0 || len(before) == len(after) {
    return ""
  }
  let head = after[0]
  if type_of(head) != "dict" {
    return ""
  }
  let role = head?.role ?? ""
  let content = head?.content ?? ""
  if role != "user" || type_of(content) != "string" {
    return ""
  }
  return content
}

fn __compaction_enabled(opts) {
  let auto_cfg = opts?.auto_compact
  let policy_cfg = opts?.compaction
  if auto_cfg == nil && policy_cfg == nil && opts?.compact_threshold == nil {
    return false
  }
  if type_of(auto_cfg) == "bool" && !auto_cfg {
    return false
  }
  if type_of(auto_cfg) == "dict" && type_of(auto_cfg?.enabled) == "bool" && !auto_cfg.enabled {
    return false
  }
  if type_of(policy_cfg) == "bool" && !policy_cfg {
    return false
  }
  if type_of(policy_cfg) == "string" && policy_cfg == "none" {
    return false
  }
  if type_of(policy_cfg) == "dict" {
    let label = policy_cfg?.strategy ?? policy_cfg?.kind ?? policy_cfg?.type
    if type_of(label) == "string" && label == "none" {
      return false
    }
  }
  return true
}

/** agent_autocompact_if_needed. */
pub fn agent_autocompact_if_needed(session, opts) {
  if !__compaction_enabled(opts) {
    return nil
  }
  let policy_label = if opts?.compaction != nil {
    __compaction_strategy_label(opts.compaction)
  } else {
    ""
  }
  let engine_strategy = if policy_label != "" {
    __compaction_engine_strategy(policy_label)
  } else if type_of(opts?.compact_strategy) == "string" {
    opts.compact_strategy
  } else {
    "observation_mask"
  }
  let keep_last = __compaction_keep_last(opts)
  let compact_opts = __compact_options(opts, engine_strategy, keep_last)
  let messages = __host_agent_session_messages(session.session_id)
  let pre_payload = {
    session: {id: session.session_id},
    strategy: if policy_label != "" {
      policy_label
    } else {
      engine_strategy
    },
    engine_strategy: engine_strategy,
    message_count: len(messages),
    keep_last: keep_last ?? 0,
  }
  let pre_control = __host_fire_session_hook("pre_compact", pre_payload)
  if pre_control?.control == "block" {
    return nil
  }
  let compacted = transcript_auto_compact(messages, compact_opts)
  let summary = __auto_compact_summary(messages, compacted)
  let archived = len(messages) - len(compacted)
  if archived > 0 {
    __host_agent_session_replace_messages(session.session_id, compacted, summary)
    let metadata = {
      strategy: if policy_label != "" {
        policy_label
      } else {
        engine_strategy
      },
      engine_strategy: engine_strategy,
      archived_messages: archived,
      new_summary_len: len(summary),
      keep_last: keep_last ?? 0,
    }
    agent_record_compaction(session.session_id, metadata)
    let post_payload = pre_payload
      + {archived_messages: archived, new_summary_len: len(summary), remaining_messages: len(compacted)}
    __host_fire_session_hook("post_compact", post_payload)
  }
  return nil
}