#!/usr/bin/env bash
# Shared helpers for the patch workflow. Sourced by every script in this dir.
#
# Layout (see README.md):
#   upstream/  pristine clone of the vendor repo   -- never edited by hand
#   work/      upstream@REV + patches/ applied     -- where you actually edit
#   patches/   the source of truth                 -- tracked in git

set -euo pipefail

ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd -P)"
UPSTREAM_URL="${UPSTREAM_URL:-https://github.com/xai-org/grok-build.git}"
UPSTREAM_BRANCH="${UPSTREAM_BRANCH:-main}"
UPSTREAM_DIR="$ROOT/upstream"
WORK_DIR="$ROOT/work"
PATCHES_DIR="$ROOT/patches"
REV_FILE="$ROOT/upstream.rev"

# Branch created inside work/, and the tag marking the pristine upstream commit
# that patches are generated against. `base` is the boundary: everything after
# it is ours.
#
# shellcheck disable=SC2034  # consumed by the scripts that source this file
WORK_BRANCH="fork"
BASE_TAG="base"

# The package that produces the shipping binary.
# shellcheck disable=SC2034  # consumed by the scripts that source this file
BIN_PKG="xai-grok-pager-bin"
# shellcheck disable=SC2034  # consumed by the scripts that source this file
BIN_NAME="xai-grok-pager"

if [[ -t 1 ]]; then
  C_RESET=$'\033[0m'; C_BOLD=$'\033[1m'; C_RED=$'\033[31m'
  C_GREEN=$'\033[32m'; C_YELLOW=$'\033[33m'; C_BLUE=$'\033[34m'
else
  C_RESET=""; C_BOLD=""; C_RED=""; C_GREEN=""; C_YELLOW=""; C_BLUE=""
fi

info() { printf '%s==>%s %s\n' "$C_BLUE$C_BOLD" "$C_RESET" "$*"; }
step() { printf '%s  ->%s %s\n' "$C_GREEN" "$C_RESET" "$*"; }
warn() { printf '%s==> warning:%s %s\n' "$C_YELLOW$C_BOLD" "$C_RESET" "$*" >&2; }
die()  { printf '%s==> error:%s %s\n' "$C_RED$C_BOLD" "$C_RESET" "$*" >&2; exit 1; }

# Rust lives in CARGO_HOME/bin, which is not on PATH by default in
# non-interactive shells. Every script that shells out to cargo needs this.
setup_path() {
  export CARGO_HOME="${CARGO_HOME:-$HOME/.cargo}"
  export RUSTUP_HOME="${RUSTUP_HOME:-$HOME/.rustup}"
  case ":$PATH:" in
    *":$CARGO_HOME/bin:"*) ;;
    *) export PATH="$CARGO_HOME/bin:$PATH" ;;
  esac
}

require_cmd() {
  command -v "$1" >/dev/null 2>&1 \
    || die "'$1' not found on PATH.${2:+ $2}"
}

# The pinned upstream commit. Comments and blank lines are allowed in the file
# so the pin can carry a note about which sync it corresponds to.
read_rev() {
  [[ -f "$REV_FILE" ]] || die "missing $REV_FILE -- run 'make update' to pin an upstream revision"
  local rev
  rev="$(grep -vE '^\s*(#|$)' "$REV_FILE" | head -n1 | tr -d '[:space:]')"
  [[ -n "$rev" ]] || die "$REV_FILE contains no revision"
  printf '%s' "$rev"
}

write_rev() {
  local rev="$1"
  {
    echo "# Pinned upstream revision of $UPSTREAM_URL"
    echo "# Bump with: make update    (never edit by hand unless you know why)"
    echo "$rev"
  } > "$REV_FILE"
}

# Clone on first use, otherwise fetch. Deliberately NOT a shallow clone: forward
# -porting patches across upstream syncs needs real history for merge bases.
ensure_upstream() {
  if [[ ! -d "$UPSTREAM_DIR/.git" ]]; then
    info "Cloning upstream $UPSTREAM_URL -> upstream/"
    git clone --branch "$UPSTREAM_BRANCH" "$UPSTREAM_URL" "$UPSTREAM_DIR"
  else
    step "Fetching upstream"
    git -C "$UPSTREAM_DIR" fetch --tags --prune origin \
      "+refs/heads/$UPSTREAM_BRANCH:refs/remotes/origin/$UPSTREAM_BRANCH"
  fi
}

# Number of .patch files currently in patches/ (0 when the dir is empty).
count_patches() {
  shopt -s nullglob
  local files=("$PATCHES_DIR"/*.patch)
  shopt -u nullglob
  printf '%s' "${#files[@]}"
}

# Guard against running rebuild/build while a patch application is half-done.
assert_no_am_in_progress() {
  local gitdir
  gitdir="$(git -C "$WORK_DIR" rev-parse --git-dir)"
  if [[ -d "$WORK_DIR/$gitdir/rebase-apply" ]]; then
    die "a 'git am' is still in progress in work/.
    Resolve it first:
      cd work && git status
      # fix conflicts, then:  git add -A && git am --continue
      # or abandon it with:   git am --abort"
  fi
}

assert_work_ready() {
  [[ -d "$WORK_DIR/.git" ]] || die "work/ does not exist yet -- run 'make apply' first"
  assert_no_am_in_progress
  git -C "$WORK_DIR" rev-parse -q --verify "refs/tags/$BASE_TAG" >/dev/null \
    || die "work/ has no '$BASE_TAG' tag -- it was not created by apply-patches.sh. Run 'make apply'."
}