#!/usr/bin/env bash
# worktree_prepare.sh — prepare an issue worktree next to the control root
# (Issue #21 item 4). Run it from the control root's skills tree: the control
# root is lib.sh's WORKSPACE_ROOT, the main checkout that owns .mam.
#
# Usage:
#   worktree_prepare.sh --path <WT> --branch <name> [--base <ref>] [--submodules]
#                       [--creator-agent <agent> [--session <name>] [--role <role>]
#                        [--herdr-session <s>] [--herdr-workspace <w>] [--onboard]] [--dry-run]
#
# Steps: git worktree (idempotent) -> .venv link to the control root's ->
# /.venv and .pytest_cache/ in the shared info/exclude -> submodules only with
# --submodules (a failed init is rolled back: it would otherwise leave a
# modules/ trace that makes a plain `git worktree remove` refuse) -> optional
# creator session registered in the control root's .mam -> summary with BASE=.
#
# Exit codes: 0 ok, 1 git / submodule / create failure, 2 usage or path rule.
set -euo pipefail

_script_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
source "$(cd "$_script_dir/../.." && pwd)/lib.sh"

usage() {
  sed -n '2,15p' "${BASH_SOURCE[0]}" | sed 's/^# \{0,1\}//'
}

WT=""; BRANCH=""; BASE_REF=""; SUBMODULES=0; DRY_RUN=0
CREATOR_AGENT=""; SESSION=""; ROLE="creator"; HS=""; HW=""; ONBOARD=0
while [ $# -gt 0 ]; do
  case "$1" in
    --path) WT="${2:-}"; shift 2 ;;
    --branch) BRANCH="${2:-}"; shift 2 ;;
    --base) BASE_REF="${2:-}"; shift 2 ;;
    --submodules) SUBMODULES=1; shift ;;
    --creator-agent) CREATOR_AGENT="${2:-}"; shift 2 ;;
    --session) SESSION="${2:-}"; shift 2 ;;
    --role) ROLE="${2:-}"; shift 2 ;;
    --herdr-session) HS="${2:-}"; shift 2 ;;
    --herdr-workspace) HW="${2:-}"; shift 2 ;;
    --onboard) ONBOARD=1; shift ;;
    --dry-run) DRY_RUN=1; shift ;;
    -h|--help) usage; exit 0 ;;
    *) echo "ERROR: unknown arg: $1" >&2; usage >&2; exit 2 ;;
  esac
done
[ -n "$WT" ] && [ -n "$BRANCH" ] || { echo "ERROR: --path and --branch are required" >&2; usage >&2; exit 2; }

MAIN="$(mam_abs_workspace "$WORKSPACE_ROOT")"
top="$(git -C "$MAIN" rev-parse --show-toplevel 2>/dev/null || true)"
if [ -z "$top" ] || [ "$(mam_abs_workspace "$top")" != "$MAIN" ]; then
  echo "ERROR: the control root '$MAIN' (WORKSPACE_ROOT) is not the top of a git checkout" >&2
  exit 2
fi

case "$WT" in /*) ;; *) WT="$PWD/$WT" ;; esac
WT="${WT%/}"
if [ -d "$WT" ]; then
  WT="$(mam_abs_workspace "$WT")"
elif [ -d "$(dirname "$WT")" ]; then
  WT="$(mam_abs_workspace "$(dirname "$WT")")/$(basename "$WT")"
fi
case "$WT/" in
  "$MAIN"/*)
    echo "ERROR: '$WT' is inside the control root '$MAIN'; a worktree there shows up as untracked files in the main tree. Put it next to the control root instead." >&2
    exit 2 ;;
esac

PY="$(_delegate_py_bin)"
wt_py() { PYTHONPATH="$SKILL_DIR:${PYTHONPATH:-}" "$PY" -m lib_py.worktree "$@"; }

if [ -z "$SESSION" ] && [ -n "$CREATOR_AGENT" ]; then
  slug="$(printf '%s' "$BRANCH" | tr '[:upper:]' '[:lower:]' | tr -c 'a-z0-9-' '-' | sed -E 's/-+/-/g; s/^-//; s/-$//')"
  SESSION="creator-${CREATOR_AGENT}-${slug}"
  SESSION="${SESSION:0:60}"
  SESSION="${SESSION%-}"
fi

if [ "$DRY_RUN" = "1" ]; then
  echo "[dry-run] control root: $MAIN"
  echo "[dry-run] worktree: $WT (branch $BRANCH${BASE_REF:+, base $BASE_REF})"
  echo "[dry-run] .venv link and shared info/exclude entries; submodules: $([ "$SUBMODULES" = 1 ] && echo init || echo skipped)"
  [ -n "$CREATOR_AGENT" ] && echo "[dry-run] creator: $CREATOR_AGENT as $SESSION (role $ROLE)"
  exit 0
fi

# 1. The worktree (idempotent).
if [ "$(wt_py is-linked "$MAIN" "$WT")" = "true" ]; then
  cur="$(git -C "$WT" branch --show-current)"
  if [ "$cur" != "$BRANCH" ]; then
    echo "ERROR: '$WT' is already a worktree, on branch '${cur:-(detached)}', not '$BRANCH'" >&2
    exit 2
  fi
  echo "worktree already prepared: $WT ($BRANCH)"
else
  if [ -e "$WT" ] && [ -n "$(ls -A "$WT" 2>/dev/null)" ]; then
    echo "ERROR: '$WT' exists and is not a worktree of '$MAIN'" >&2
    exit 2
  fi
  mkdir -p "$(dirname "$WT")"
  if git -C "$MAIN" show-ref --verify --quiet "refs/heads/$BRANCH"; then
    git -C "$MAIN" worktree add "$WT" "$BRANCH" || exit 1
  else
    git -C "$MAIN" worktree add -b "$BRANCH" "$WT" "${BASE_REF:-HEAD}" || exit 1
  fi
fi

# 2. .venv: a link to the control root's, never a copy.
if [ -e "$MAIN/.venv" ]; then
  if [ ! -e "$WT/.venv" ] && [ ! -L "$WT/.venv" ]; then
    ln -s "$MAIN/.venv" "$WT/.venv"
  elif [ "$(readlink "$WT/.venv" 2>/dev/null || true)" != "$MAIN/.venv" ]; then
    echo "WARNING: '$WT/.venv' exists and is not a link to '$MAIN/.venv'; left as it is" >&2
  fi
fi

# 3. Ignore rules. A linked worktree's info/exclude is the shared
#    $GIT_COMMON_DIR/info/exclude, so these lines apply to the main checkout too
#    (they name artefacts it ignores as well).
excl="$(cd "$WT" && git rev-parse --path-format=absolute --git-path info/exclude)"
mkdir -p "$(dirname "$excl")"
touch "$excl"
if [ -s "$excl" ] && [ -n "$(tail -c1 "$excl")" ]; then echo >> "$excl"; fi
for pat in "/.venv" ".pytest_cache/"; do
  grep -Fxq -- "$pat" "$excl" || printf '%s\n' "$pat" >> "$excl"
done

# 4. Submodules: opt-in only.
SUB_STATE="skipped"
if [ -f "$WT/.gitmodules" ]; then
  if [ "$SUBMODULES" = "1" ]; then
    gd="$(git -C "$WT" rev-parse --absolute-git-dir)"
    had_modules=0
    [ -e "$gd/modules" ] && had_modules=1
    new_keys=()
    while read -r key _; do
      [ -n "$key" ] || continue
      name="${key#submodule.}"; name="${name%.path}"
      for k in url active; do
        git -C "$MAIN" config --get "submodule.$name.$k" >/dev/null 2>&1 || new_keys+=("submodule.$name.$k")
      done
    done < <(git config --file "$WT/.gitmodules" --get-regexp '^submodule\..*\.path$' 2>/dev/null || true)
    if ! git -C "$WT" submodule update --init --recursive; then
      [ "$had_modules" = "1" ] || rm -rf "$gd/modules"
      for k in ${new_keys[@]+"${new_keys[@]}"}; do
        git -C "$MAIN" config --unset-all "$k" 2>/dev/null || true
      done
      echo "ERROR: submodule initialisation failed; its traces (modules/, new submodule.* config keys) were removed so the worktree can still be removed without --force. Re-run without --submodules to finish preparing." >&2
      exit 1
    fi
    SUB_STATE="initialised"
  else
    echo "NOTE: submodules were not initialised (pass --submodules to initialise them)"
  fi
fi

# 5. Optional creator, registered in the control root's .mam.
if [ -n "$CREATOR_AGENT" ]; then
  args=(--workspace "$WT" --agent "$CREATOR_AGENT" --role "$ROLE" --session "$SESSION")
  if [ "$ONBOARD" = "1" ]; then args+=(--onboard); else args+=(--no-onboard); fi
  if [ -n "$HS" ]; then args+=(--herdr-session "$HS"); fi
  if [ -n "$HW" ]; then args+=(--herdr-workspace "$HW"); fi
  env_add=(WORKSPACE_ROOT="$MAIN"
           AGENT_SESSIONS_YAML="${AGENT_SESSIONS_YAML:-$MAIN/.mam/agent-sessions.yaml}"
           MAM_JOBS_DIR="${MAM_JOBS_DIR:-$MAIN/.mam/jobs}"
           DELEGATE_JOB_LOGS_DIR="${DELEGATE_JOB_LOGS_DIR:-$MAIN/.mam/delegate_job_logs}"
           MAM_NO_SUBSCRIBER_DAEMON=1)
  if [ -z "${MAM_ENV_FILE:-}" ] && [ -f "$MAIN/.mam.env" ]; then env_add+=(MAM_ENV_FILE="$MAIN/.mam.env"); fi
  rc=0
  env "${env_add[@]}" bash "$SKILL_DIR/multi-agent-mux-create/scripts/create_session.sh" "${args[@]}" || rc=$?
  if [ "$rc" -ne 0 ]; then
    echo "ERROR: create_session.sh failed (rc=$rc); the worktree is kept - remove it with worktree_remove.sh --path '$WT'" >&2
    exit "$rc"
  fi
fi

BASE_SHA="$(git -C "$WT" rev-parse HEAD)"
echo "WORKTREE=$WT"
echo "BRANCH=$BRANCH"
echo "BASE=$BASE_SHA"
echo "SUBMODULES=$SUB_STATE"
[ -n "$CREATOR_AGENT" ] && echo "SESSION=$SESSION"
echo "next: bash $SKILL_DIR/multi-agent-mux-loop/scripts/run_loop.sh --worktree '$WT' --base $BASE_SHA --review-only --creator <creator> --reviewer <reviewers> --task '...'"
echo "then: bash $SKILL_DIR/multi-agent-mux-stop/scripts/worktree_remove.sh --path '$WT' --stop"