#!/usr/bin/env bash
# gitflow.sh — mechanical core of the gitflow model.
#
# Two ways in:
#   - SOURCED by tests / skills that want the functions.
#   - EXECUTED as a CLI dispatcher: `gitflow.sh <op> [args]` (how skills call it,
#     one Bash invocation per operation).
#
# The judgment layer (WHEN to finish — the human gate) lives in skills/gitflow/
# SKILL.md, never here. This file only does the deterministic mechanics, so it
# can be tested on throwaway repos. Mirrors the surgical-commit helper style:
# `set -uo pipefail` on execute, argv arrays, fail loud, no global state.

_GITFLOW_LIB_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

# ── branch model ─────────────────────────────────────────────────────────────
GITFLOW_MAIN="main"
GITFLOW_DEVELOP="develop"
# template resolved relative to the lib; overridable for tests.
GITFLOW_GITIGNORE_TEMPLATE="${GITFLOW_GITIGNORE_TEMPLATE:-$_GITFLOW_LIB_DIR/../templates/gitignore/standard.gitignore}"

# ── predicates / pure helpers ────────────────────────────────────────────────

# echo the gitflow type of a branch: feature|bugfix|release|hotfix|main|develop|other
gitflow_branch_type() {
  local br="${1:-$(git symbolic-ref --short -q HEAD 2>/dev/null)}"
  case "$br" in
    "$GITFLOW_MAIN")    echo main ;;
    "$GITFLOW_DEVELOP") echo develop ;;
    feature/*)          echo feature ;;
    bugfix/*)           echo bugfix ;;
    release/*)          echo release ;;
    hotfix/*)           echo hotfix ;;
    *)                  echo other ;;
  esac
}

# THE shared predicate — rc 0 iff (given or current) branch is a protected base.
# Consumed by: start/finish (here), the assistance skills (aiguillage), and the
# pre-commit hook (mirrored, coherence-tested — see gitflow-test.sh T10).
gitflow_protected_base() {
  local br="${1:-$(git symbolic-ref --short -q HEAD 2>/dev/null)}"
  [ "$br" = "$GITFLOW_MAIN" ] || [ "$br" = "$GITFLOW_DEVELOP" ]
}

# echo the base a given type must fork from.
gitflow_base_for() {
  case "$1" in
    feature|bugfix|release) echo "$GITFLOW_DEVELOP" ;;
    hotfix)                 echo "$GITFLOW_MAIN" ;;
    *) echo "gitflow: unknown type '$1'" >&2; return 2 ;;
  esac
}

# rc 0 iff at least one release/* branch exists (hotfix fan-out condition).
gitflow_release_open() {
  [ -n "$(git for-each-ref --format='%(refname:short)' 'refs/heads/release/*')" ]
}

# ── start ────────────────────────────────────────────────────────────────────

# gitflow_start <type> <name> → checkout -b <type>/<name> from the correct base.
gitflow_start() {
  local type="${1:-}" name="${2:-}" base
  base="$(gitflow_base_for "$type")" || return 2
  [ -n "$name" ] || { echo "gitflow_start: missing <name>" >&2; return 2; }
  git rev-parse --verify -q "$base" >/dev/null \
    || { echo "gitflow_start: base '$base' missing — run 'gitflow init' first" >&2; return 3; }
  git checkout -q "$base" || return 1
  git pull --ff-only -q 2>/dev/null || true   # best-effort sync; offline / no-upstream ok
  git checkout -q -b "$type/$name" || return 1
  echo "$type/$name"
}

# ── finish (directed merge + hotfix fan-out) ─────────────────────────────────

_gitflow_merge_into() {            # _gitflow_merge_into <target> <source>
  local target="$1" source="$2"
  git checkout -q "$target" || return 1
  git pull --ff-only -q 2>/dev/null || true
  git merge --no-ff -q -m "Merge $source into $target" "$source" \
    || { echo "gitflow: conflict merging $source → $target — resolve, commit, re-run finish" >&2; return 4; }
}

_gitflow_merge_into_open_releases() {   # <source>
  local source="$1" rel
  while IFS= read -r rel; do
    [ -n "$rel" ] || continue
    _gitflow_merge_into "$rel" "$source" || return 4
  done < <(git for-each-ref --format='%(refname:short)' 'refs/heads/release/*')
}

_gitflow_delete() {                # <branch>
  local br="$1"
  git checkout -q "$GITFLOW_DEVELOP" 2>/dev/null || git checkout -q "$GITFLOW_MAIN"
  git branch -q -d "$br" || { echo "gitflow: '$br' not fully merged — branch kept" >&2; return 5; }
}

# gitflow_finish → directed merge of the CURRENT branch per its type, then delete.
# WHEN to call this is the human gate (SKILL.md). This only performs the merge.
gitflow_finish() {
  local br type
  br="$(git symbolic-ref --short -q HEAD)" || { echo "gitflow_finish: detached HEAD" >&2; return 3; }
  type="$(gitflow_branch_type "$br")"
  case "$type" in
    feature|bugfix)
      _gitflow_merge_into "$GITFLOW_DEVELOP" "$br" && _gitflow_delete "$br" ;;
    release)
      _gitflow_merge_into "$GITFLOW_MAIN" "$br" \
        && _gitflow_merge_into "$GITFLOW_DEVELOP" "$br" \
        && _gitflow_delete "$br" ;;
    hotfix)
      _gitflow_merge_into "$GITFLOW_MAIN" "$br" \
        && _gitflow_merge_into "$GITFLOW_DEVELOP" "$br" \
        && { gitflow_release_open && _gitflow_merge_into_open_releases "$br" || true; } \
        && _gitflow_delete "$br" ;;
    *) echo "gitflow_finish: '$br' is not a finishable gitflow branch" >&2; return 2 ;;
  esac
}

# ── init (resolves BLK-010) + reconcile + hook install ───────────────────────

_gitflow_init_fresh() {            # unborn HEAD → deterministic root commit on main
  local msg="${1:-chore: initial commit}"
  git symbolic-ref HEAD "refs/heads/$GITFLOW_MAIN"   # name the unborn branch 'main'
  git add -A
  git commit -q -m "$msg" \
    || { echo "gitflow_init: nothing staged for the root commit (scaffold first)" >&2; return 1; }
  git branch "$GITFLOW_DEVELOP"
}

_gitflow_init_existing() {         # has commits → ensure main (rename master) + develop
  if ! git rev-parse --verify -q "refs/heads/$GITFLOW_MAIN" >/dev/null; then
    if git rev-parse --verify -q refs/heads/master >/dev/null; then
      git branch -m master "$GITFLOW_MAIN"
    else
      echo "gitflow_init: no '$GITFLOW_MAIN' and no 'master' — refusing to guess the prod branch" >&2
      return 2
    fi
  fi
  git checkout -q "$GITFLOW_MAIN" || return 1
  # commit the socle + versioned hook now, while hooksPath is NOT yet active
  # (activation is the last step of gitflow_init) → never self-blocked.
  git add -- .gitignore .githooks 2>/dev/null || true
  # socle commit failure is FATAL — abort BEFORE develop/hook-activation so a
  # partial run can't activate the hook and self-block every re-run (was a bug:
  # the `|| commit` form swallowed the failure, then init activated the hook).
  if ! git diff --cached --quiet -- .gitignore .githooks 2>/dev/null; then
    git commit -q -m "chore: adopt gitflow socle + pre-commit hook" \
      || { echo "gitflow_init: socle commit failed — aborting before hook activation (recoverable)" >&2; return 1; }
  fi
  git rev-parse --verify -q "refs/heads/$GITFLOW_DEVELOP" >/dev/null \
    || git branch "$GITFLOW_DEVELOP" "$GITFLOW_MAIN"
}

# gitflow_init [msg] → idempotent. Order matters (full BLK-010 closure):
# reconcile .gitignore + write the versioned hook FIRST, so the fresh root
# commit / existing adoption commit EMBED them; activate the hook LAST so the
# bootstrap commits are never self-blocked by the hook they install.
gitflow_init() {
  git rev-parse --git-dir >/dev/null 2>&1 || { echo "gitflow_init: not a git repo" >&2; return 1; }
  # identity precheck — without it the root/socle commit fails mid-run (see fatal
  # guard in _gitflow_init_existing). Fail loud up front instead of half-applying.
  { [ -n "$(git config user.name)" ] && [ -n "$(git config user.email)" ]; } \
    || { echo "gitflow_init: git identity unset (user.name/user.email) — set it first" >&2; return 1; }
  gitflow_reconcile_gitignore || return $?   # socle into .gitignore BEFORE any commit
  _gitflow_write_hook || return $?           # write .githooks/pre-commit (inactive)
  if ! git rev-parse --verify -q HEAD >/dev/null 2>&1; then
    _gitflow_init_fresh "$@" || return $?     # root commit embeds scaffold + socle + hook
  else
    _gitflow_init_existing || return $?       # adoption commit (hook still inactive)
  fi
  gitflow_activate_hook || return $?          # activate LAST
}

# Additive reconcile: ensure every non-comment template line is present; append
# only what's missing under a managed marker. NEVER rewrites project-own rules.
gitflow_reconcile_gitignore() {
  local tmpl="$GITFLOW_GITIGNORE_TEMPLATE" gi=".gitignore" line
  local -a missing=()
  [ -f "$tmpl" ] || { echo "gitflow: gitignore template missing: $tmpl" >&2; return 1; }
  [ -e "$gi" ] || : > "$gi"
  while IFS= read -r line; do
    case "$line" in ''|\#*) continue ;; esac
    grep -qxF -- "$line" "$gi" || missing+=("$line")
  done < "$tmpl"
  [ "${#missing[@]}" -gt 0 ] || return 0          # idempotent no-op
  {
    echo ""
    echo "# ── gitflow standard socle (added by gitflow_init; additive, safe to edit) ──"
    printf '%s\n' "${missing[@]}"
  } >> "$gi"
  echo "gitflow: appended ${#missing[@]} socle line(s) to $gi" >&2
}

# Emit the self-contained pre-commit hook. The protected-base test is INLINED
# (mirror of gitflow_protected_base) because the hook runs in arbitrary project
# repos with no access to this lib. Coherence guaranteed by gitflow-test.sh T10.
_gitflow_emit_pre_commit() {
cat <<HOOK
#!/bin/sh
# gitflow pre-commit — generated by gitflow_init. Do not hand-edit.
# Mirrors gitflow_protected_base (lib/gitflow.sh). Drift caught by T10.
gd=\$(git rev-parse --git-dir)
br=\$(git symbolic-ref --short -q HEAD 2>/dev/null)

git rev-parse --verify -q HEAD >/dev/null 2>&1 || exit 0   # root commit — allow
[ -f "\$gd/MERGE_HEAD" ] && exit 0                          # merge in progress — allow

case "\$br" in
  $GITFLOW_MAIN|$GITFLOW_DEVELOP) ;;                        # protected — keep checking
  *) exit 0 ;;                                              # working branch — allow
esac

# whitelist: all-staged-under-.claude/ (memory/doc/deploy helpers) — allow
if [ -z "\$(git diff --cached --name-only | grep -v '^\.claude/' | head -1)" ]; then
  exit 0
fi

echo "gitflow pre-commit: BLOCKED — direct commit on '\$br'." >&2
echo "  Branch from the right base (feature/bugfix->develop, hotfix->main), or merge." >&2
echo "  (.claude/** memory commits are exempt; --no-verify bypasses locally.)" >&2
exit 1
HOOK
}

# write the versioned hook file — does NOT activate (see gitflow_activate_hook).
_gitflow_write_hook() {
  local hd=".githooks"
  mkdir -p "$hd"
  _gitflow_emit_pre_commit > "$hd/pre-commit"
  chmod +x "$hd/pre-commit"
}

# point git at the versioned hook dir. Run LAST in init so the bootstrap commits
# (socle / adoption / root) are never blocked by the hook they install.
gitflow_activate_hook() {
  git config core.hooksPath .githooks
}

# convenience: write + activate in one call (re-install / CLI 'install-hook').
gitflow_install_hook() {
  _gitflow_write_hook && gitflow_activate_hook
}

# ── CLI dispatch (only when executed, not sourced) ───────────────────────────
if [ "${BASH_SOURCE[0]}" = "${0}" ]; then
  set -uo pipefail
  cmd="${1:-}"; shift 2>/dev/null || true
  case "$cmd" in
    type)           gitflow_branch_type "$@" ;;
    protected-base) gitflow_protected_base "$@" ;;
    base-for)       gitflow_base_for "$@" ;;
    release-open)   gitflow_release_open ;;
    start)          gitflow_start "$@" ;;
    finish)         gitflow_finish "$@" ;;
    init)           gitflow_init "$@" ;;
    reconcile)      gitflow_reconcile_gitignore "$@" ;;
    install-hook)   gitflow_install_hook "$@" ;;
    emit-hook)      _gitflow_emit_pre_commit ;;
    *) echo "usage: gitflow.sh {type|protected-base|base-for|release-open|start|finish|init|reconcile|install-hook|emit-hook}" >&2; exit 2 ;;
  esac
fi