#!/usr/bin/env bash
# formula-session.sh — Shared helpers for formula-driven cron agents
#
# Provides reusable functions for the common cron-wrapper + tmux-session
# pattern used by planner-run.sh, predictor-run.sh, gardener-run.sh, and supervisor-run.sh.
#
# Functions:
#   acquire_cron_lock   LOCK_FILE          — PID lock with stale cleanup
#   check_memory        [MIN_MB]           — skip if available RAM too low
#   load_formula        FORMULA_FILE       — sets FORMULA_CONTENT
#   build_context_block FILE [FILE ...]    — sets CONTEXT_BLOCK
#   start_formula_session SESSION WORKDIR PHASE_FILE — create tmux + claude
#   build_prompt_footer    [EXTRA_API]      — sets PROMPT_FOOTER (API ref + env + phase)
#   run_formula_and_monitor AGENT [TIMEOUT] [CALLBACK] — session start, inject, monitor, log
#   formula_phase_callback PHASE           — standard crash-recovery callback
#
# Requires: lib/agent-session.sh sourced first (for create_agent_session,
# agent_kill_session, agent_inject_into_session).
# Globals used by formula_phase_callback: SESSION_NAME, PHASE_FILE,
# PROJECT_REPO_ROOT, PROMPT (set by the calling script).

# ── Cron guards ──────────────────────────────────────────────────────────

# acquire_cron_lock LOCK_FILE
# Acquires a PID lock. Exits 0 if another instance is running.
# Sets an EXIT trap to clean up the lock file.
acquire_cron_lock() {
  _CRON_LOCK_FILE="$1"
  if [ -f "$_CRON_LOCK_FILE" ]; then
    local lock_pid
    lock_pid=$(cat "$_CRON_LOCK_FILE" 2>/dev/null || true)
    if [ -n "$lock_pid" ] && kill -0 "$lock_pid" 2>/dev/null; then
      log "run: already running (PID $lock_pid)"
      exit 0
    fi
    rm -f "$_CRON_LOCK_FILE"
  fi
  echo $$ > "$_CRON_LOCK_FILE"
  trap 'rm -f "$_CRON_LOCK_FILE"' EXIT
}

# check_memory [MIN_MB]
# Exits 0 (skip) if available memory is below MIN_MB (default 2000).
check_memory() {
  local min_mb="${1:-2000}"
  local avail_mb
  avail_mb=$(free -m | awk '/Mem:/{print $7}')
  if [ "${avail_mb:-0}" -lt "$min_mb" ]; then
    log "run: skipping — only ${avail_mb}MB available (need ${min_mb})"
    exit 0
  fi
}

# ── Formula loading ──────────────────────────────────────────────────────

# load_formula FORMULA_FILE
# Reads formula TOML into FORMULA_CONTENT. Exits 1 if missing.
load_formula() {
  local formula_file="$1"
  if [ ! -f "$formula_file" ]; then
    log "ERROR: formula not found: $formula_file"
    exit 1
  fi
  # shellcheck disable=SC2034  # consumed by the calling script
  FORMULA_CONTENT=$(cat "$formula_file")
}

# build_context_block FILE [FILE ...]
# Reads each file from $PROJECT_REPO_ROOT and builds CONTEXT_BLOCK.
# Files prefixed with "ops:" are read from $OPS_REPO_ROOT instead.
build_context_block() {
  CONTEXT_BLOCK=""
  local ctx ctx_path ctx_label
  for ctx in "$@"; do
    case "$ctx" in
      ops:*)
        ctx_label="${ctx#ops:}"
        ctx_path="${OPS_REPO_ROOT}/${ctx_label}"
        ;;
      *)
        ctx_label="$ctx"
        ctx_path="${PROJECT_REPO_ROOT}/${ctx}"
        ;;
    esac
    if [ -f "$ctx_path" ]; then
      CONTEXT_BLOCK="${CONTEXT_BLOCK}
### ${ctx_label}
$(cat "$ctx_path")
"
    fi
  done
}

# ── Ops repo helpers ─────────────────────────────────────────────────

# ensure_ops_repo
# Clones or pulls the ops repo so agents can read/write operational data.
# Requires: OPS_REPO_ROOT, FORGE_OPS_REPO, FORGE_URL, FORGE_TOKEN.
# No-op if OPS_REPO_ROOT already exists and is up-to-date.
ensure_ops_repo() {
  local ops_root="${OPS_REPO_ROOT:-}"
  [ -n "$ops_root" ] || return 0

  if [ -d "${ops_root}/.git" ]; then
    # Pull latest from primary branch
    git -C "$ops_root" fetch origin "${PRIMARY_BRANCH}" --quiet 2>/dev/null || true
    git -C "$ops_root" checkout "${PRIMARY_BRANCH}" --quiet 2>/dev/null || true
    git -C "$ops_root" pull --ff-only origin "${PRIMARY_BRANCH}" --quiet 2>/dev/null || true
    return 0
  fi

  # Clone from Forgejo
  local ops_repo="${FORGE_OPS_REPO:-}"
  [ -n "$ops_repo" ] || return 0
  local forge_url="${FORGE_URL:-http://localhost:3000}"
  local clone_url
  if [ -n "${FORGE_TOKEN:-}" ]; then
    local auth_url
    auth_url=$(printf '%s' "$forge_url" | sed "s|://|://$(whoami):${FORGE_TOKEN}@|")
    clone_url="${auth_url}/${ops_repo}.git"
  else
    clone_url="${forge_url}/${ops_repo}.git"
  fi

  log "Cloning ops repo: ${ops_repo} -> ${ops_root}"
  if git clone --quiet "$clone_url" "$ops_root" 2>/dev/null; then
    log "Ops repo cloned: ${ops_root}"
  else
    log "WARNING: failed to clone ops repo ${ops_repo} — creating local directory"
    mkdir -p "$ops_root"
  fi
}

# ops_commit_and_push MESSAGE [FILE ...]
# Stage, commit, and push changes in the ops repo.
# If no files specified, stages all changes.
ops_commit_and_push() {
  local msg="$1"
  shift
  local ops_root="${OPS_REPO_ROOT:-}"
  [ -d "${ops_root}/.git" ] || return 0

  (
    cd "$ops_root" || return
    if [ $# -gt 0 ]; then
      git add "$@"
    else
      git add -A
    fi
    if ! git diff --cached --quiet; then
      git commit -m "$msg"
      git push origin "${PRIMARY_BRANCH}" --quiet 2>/dev/null || true
    fi
  )
}

# ── Session management ───────────────────────────────────────────────────

# start_formula_session SESSION WORKDIR PHASE_FILE
# Kills stale session, resets phase file, creates a per-agent git worktree
# for session isolation, and creates a new tmux + claude session in it.
# Sets _FORMULA_SESSION_WORKDIR to the worktree path (or original workdir
# on fallback). Callers must clean up via remove_formula_worktree after
# the session ends.
# Returns 0 on success, 1 on failure.
start_formula_session() {
  local session="$1" workdir="$2" phase_file="$3"
  agent_kill_session "$session"
  rm -f "$phase_file"

  # Create per-agent git worktree for session isolation.
  # Each agent gets its own CWD so Claude Code treats them as separate
  # projects — no resume collisions between sequential formula runs.
  _FORMULA_SESSION_WORKDIR="/tmp/disinto-${session}"
  # Clean up any stale worktree from a previous run
  git -C "$workdir" worktree remove "$_FORMULA_SESSION_WORKDIR" --force 2>/dev/null || true
  if git -C "$workdir" worktree add "$_FORMULA_SESSION_WORKDIR" HEAD --detach 2>/dev/null; then
    log "Created worktree: ${_FORMULA_SESSION_WORKDIR}"
  else
    log "WARNING: worktree creation failed — falling back to ${workdir}"
    _FORMULA_SESSION_WORKDIR="$workdir"
  fi

  log "Creating tmux session: ${session}"
  if ! create_agent_session "$session" "$_FORMULA_SESSION_WORKDIR" "$phase_file"; then
    log "ERROR: failed to create tmux session ${session}"
    return 1
  fi
}

# remove_formula_worktree
# Removes the worktree created by start_formula_session if it differs from
# PROJECT_REPO_ROOT. Safe to call multiple times. No-op if no worktree was created.
remove_formula_worktree() {
  if [ -n "${_FORMULA_SESSION_WORKDIR:-}" ] \
     && [ "$_FORMULA_SESSION_WORKDIR" != "${PROJECT_REPO_ROOT:-}" ]; then
    git -C "$PROJECT_REPO_ROOT" worktree remove "$_FORMULA_SESSION_WORKDIR" --force 2>/dev/null || true
    log "Removed worktree: ${_FORMULA_SESSION_WORKDIR}"
  fi
}

# formula_phase_callback PHASE
# Standard crash-recovery phase callback for formula sessions.
# Requires globals: SESSION_NAME, PHASE_FILE, PROJECT_REPO_ROOT, PROMPT.
# Uses _FORMULA_CRASH_COUNT (auto-initialized) for single-retry limit.
# shellcheck disable=SC2154  # SESSION_NAME, PHASE_FILE, PROJECT_REPO_ROOT, PROMPT set by caller
formula_phase_callback() {
  local phase="$1"
  log "phase: ${phase}"
  case "$phase" in
    PHASE:crashed)
      if [ "${_FORMULA_CRASH_COUNT:-0}" -gt 0 ]; then
        log "ERROR: session crashed again after recovery — giving up"
        return 0
      fi
      _FORMULA_CRASH_COUNT=$(( ${_FORMULA_CRASH_COUNT:-0} + 1 ))
      log "WARNING: tmux session died unexpectedly — attempting recovery"
      if create_agent_session "${_MONITOR_SESSION:-$SESSION_NAME}" "${_FORMULA_SESSION_WORKDIR:-$PROJECT_REPO_ROOT}" "$PHASE_FILE" 2>/dev/null; then
        agent_inject_into_session "${_MONITOR_SESSION:-$SESSION_NAME}" "$PROMPT"
        log "Recovery session started"
      else
        log "ERROR: could not restart session after crash"
      fi
      ;;
    PHASE:done|PHASE:failed|PHASE:escalate|PHASE:merged)
      agent_kill_session "${_MONITOR_SESSION:-$SESSION_NAME}"
      ;;
  esac
}

# ── Stale crashed worktree cleanup ─────────────────────────────────────────

# cleanup_stale_crashed_worktrees [MAX_AGE_HOURS]
# Thin wrapper around worktree_cleanup_stale() from lib/worktree.sh.
# Kept for backwards compatibility with existing callers.
# Requires: lib/worktree.sh sourced.
cleanup_stale_crashed_worktrees() {
  worktree_cleanup_stale "${1:-24}"
}

# ── Scratch file helpers (compaction survival) ────────────────────────────

# build_scratch_instruction SCRATCH_FILE
# Returns a prompt block instructing Claude to periodically flush context
# to a scratch file so understanding survives context compaction.
build_scratch_instruction() {
  local scratch_file="$1"
  cat <<_SCRATCH_EOF_
## Context scratch file (compaction survival)

Periodically (every 10-15 tool calls), write a summary of:
- What you have discovered so far
- Decisions made and why
- What remains to do
to: ${scratch_file}

If this file existed at session start, its contents have already been injected into your prompt above.
This file is ephemeral — not evidence or permanent memory, just a compaction survival mechanism.
_SCRATCH_EOF_
}

# read_scratch_context SCRATCH_FILE
# If the scratch file exists, returns a context block for prompt injection.
# Returns empty string if the file does not exist.
read_scratch_context() {
  local scratch_file="$1"
  if [ -f "$scratch_file" ]; then
    printf '## Previous context (from scratch file)\n%s\n' "$(head -c 8192 "$scratch_file")"
  fi
}

# ── Graph report helper ───────────────────────────────────────────────────

# build_graph_section
# Runs build-graph.py and sets GRAPH_SECTION to a markdown block containing
# the JSON report.  Sets GRAPH_SECTION="" on failure (non-fatal).
# Requires globals: PROJECT_NAME, FACTORY_ROOT, PROJECT_REPO_ROOT, LOG_FILE.
build_graph_section() {
  local report="/tmp/${PROJECT_NAME}-graph-report.json"
  # shellcheck disable=SC2034  # consumed by the calling script's PROMPT
  GRAPH_SECTION=""
  if python3 "$FACTORY_ROOT/lib/build-graph.py" \
       --project-root "$PROJECT_REPO_ROOT" \
       --output "$report" 2>>"$LOG_FILE"; then
    # shellcheck disable=SC2034
    GRAPH_SECTION=$(printf '\n## Structural analysis\n```json\n%s\n```\n' \
      "$(cat "$report")")
    log "graph report generated: $(jq -r '.stats | "\(.nodes) nodes, \(.edges) edges"' "$report")"
  else
    log "WARN: build-graph.py failed — continuing without structural analysis"
  fi
}

# ── SDK helpers ───────────────────────────────────────────────────────────

# build_sdk_prompt_footer [EXTRA_API_LINES]
# Like build_prompt_footer but omits the phase protocol section (SDK mode).
# Sets PROMPT_FOOTER.
build_sdk_prompt_footer() {
  # shellcheck disable=SC2034  # consumed by build_prompt_footer
  PHASE_FILE=""  # not used in SDK mode
  build_prompt_footer "${1:-}"
  PROMPT_FOOTER="${PROMPT_FOOTER%%## Phase protocol*}"
}

# formula_worktree_setup WORKTREE
# Creates an isolated worktree for synchronous formula execution.
# Fetches primary branch, cleans stale worktree, creates new one, and
# sets an EXIT trap for cleanup.
# Requires globals: PROJECT_REPO_ROOT, PRIMARY_BRANCH.
formula_worktree_setup() {
  local worktree="$1"
  cd "$PROJECT_REPO_ROOT" || return
  git fetch origin "$PRIMARY_BRANCH" 2>/dev/null || true
  worktree_cleanup "$worktree"
  git worktree add "$worktree" "origin/${PRIMARY_BRANCH}" --detach 2>/dev/null
  # shellcheck disable=SC2064  # expand worktree now, not at trap time
  trap "worktree_cleanup '$worktree'" EXIT
}

# ── Prompt + monitor helpers ──────────────────────────────────────────────

# build_prompt_footer [EXTRA_API_LINES]
# Assembles the common forge API reference + environment + phase protocol
# block for formula prompts.  Sets PROMPT_FOOTER.
# Pass additional API endpoint lines (pre-formatted, newline-prefixed) via $1.
# Requires globals: FORGE_API, FACTORY_ROOT, PROJECT_REPO_ROOT,
#                   PRIMARY_BRANCH, PHASE_FILE.
build_prompt_footer() {
  local extra_api="${1:-}"
  # shellcheck disable=SC2034  # consumed by the calling script's PROMPT
  PROMPT_FOOTER="## Forge API reference
Base URL: ${FORGE_API}
Auth header: -H \"Authorization: token \${FORGE_TOKEN}\"
  Read issue:  curl -sf -H \"Authorization: token \${FORGE_TOKEN}\" '${FORGE_API}/issues/{number}' | jq '.body'
  Create issue: curl -sf -X POST -H \"Authorization: token \${FORGE_TOKEN}\" -H 'Content-Type: application/json' '${FORGE_API}/issues' -d '{\"title\":\"...\",\"body\":\"...\",\"labels\":[LABEL_ID]}'${extra_api}
  List labels: curl -sf -H \"Authorization: token \${FORGE_TOKEN}\" '${FORGE_API}/labels'
NEVER echo or include the actual token value in output — always reference \${FORGE_TOKEN}.

## Environment
FACTORY_ROOT=${FACTORY_ROOT}
PROJECT_REPO_ROOT=${PROJECT_REPO_ROOT}
OPS_REPO_ROOT=${OPS_REPO_ROOT}
PRIMARY_BRANCH=${PRIMARY_BRANCH}
PHASE_FILE=${PHASE_FILE}

## Phase protocol (REQUIRED)
When all work is done:
  echo 'PHASE:done' > '${PHASE_FILE}'
On unrecoverable error:
  printf 'PHASE:failed\nReason: %s\n' 'describe error' > '${PHASE_FILE}'"
}

# run_formula_and_monitor AGENT_NAME [TIMEOUT]
# Starts the formula session, injects PROMPT, monitors phase, and logs result.
# Requires globals: SESSION_NAME, PHASE_FILE, PROJECT_REPO_ROOT, PROMPT,
#                   FORGE_REPO, CLAUDE_MODEL (exported).
# shellcheck disable=SC2154  # SESSION_NAME, PHASE_FILE, PROJECT_REPO_ROOT, PROMPT set by caller
run_formula_and_monitor() {
  local agent_name="$1"
  local timeout="${2:-7200}"
  local callback="${3:-formula_phase_callback}"

  if ! start_formula_session "$SESSION_NAME" "$PROJECT_REPO_ROOT" "$PHASE_FILE"; then
    exit 1
  fi

  # Write phase protocol to context file for compaction survival
  if [ -n "${PROMPT_FOOTER:-}" ]; then
    write_compact_context "$PHASE_FILE" "$PROMPT_FOOTER"
  fi

  agent_inject_into_session "$SESSION_NAME" "$PROMPT"
  log "Prompt sent to tmux session"

  log "Monitoring phase file: ${PHASE_FILE}"
  _FORMULA_CRASH_COUNT=0

  monitor_phase_loop "$PHASE_FILE" "$timeout" "$callback"

  FINAL_PHASE=$(read_phase "$PHASE_FILE")
  log "Final phase: ${FINAL_PHASE:-none}"

  if [ "$FINAL_PHASE" != "PHASE:done" ]; then
    case "${_MONITOR_LOOP_EXIT:-}" in
      idle_prompt)
        log "${agent_name}: Claude returned to prompt without writing phase signal"
        ;;
      idle_timeout)
        log "${agent_name}: timed out with no phase signal"
        ;;
      *)
        log "${agent_name} finished without PHASE:done (phase: ${FINAL_PHASE:-none}, exit: ${_MONITOR_LOOP_EXIT:-})"
        ;;
    esac
  fi

  # Preserve worktree on crash for debugging; clean up on success
  if [ "${_MONITOR_LOOP_EXIT:-}" = "crashed" ]; then
    worktree_preserve "${_FORMULA_SESSION_WORKDIR:-}" "crashed (agent=${agent_name})"
  else
    remove_formula_worktree
  fi

  log "--- ${agent_name^} run done ---"
}