#!/usr/bin/env bash
# Run all install-reviewer preconditions and report them as one JSON
# result. The skill invokes this before any mutation so every preflight
# failure is surfaced together, not one-at-a-time. Checks cover: git
# worktree, GitHub CLI installation + auth, packaged template presence,
# origin remote, and (mode-dependent) branch state. In override mode it also
# refuses to overwrite uncommitted local changes to any reviewer target.
#
# Usage: preflight.sh [--override]
#   --override    Upgrade existing scaffolded reviewers in place (instead
#                 of failing on their existence per the install-mode
#                 safety gate). Skips the branch-not-local /
#                 branch-not-remote checks (the upgrade branch can
#                 legitimately already exist from a prior in-flight
#                 attempt) and adds a no-dirty-target-edits check
#                 covering four clobber-states the upgrade refuses to
#                 overwrite — uncommitted edits, untracked content,
#                 symlinks, and tracked deletions (HEAD-present,
#                 working-tree-removed) — so the consumer commits,
#                 stashes, restores, or removes the local content
#                 before the scaffold replaces their files.
# Out:   one JSON object on stdout:
#          {"ok": bool,
#           "override": bool,
#           "failures": [{"check": "<name>", "reason": "<human text>"}, ...],
#           "warnings": [{"check": "<name>", "reason": "<human text>"}, ...]}
#        When ok is false, each failure includes a concrete recovery
#        command where applicable. Warnings are informational only —
#        they surface advisory findings and never set ok to false or
#        change the exit code.
# Exit:  0 if ok is true; 1 if any check fails

set -euo pipefail

OVERRIDE_MODE=0
for arg in "$@"; do
  case "$arg" in
    --override) OVERRIDE_MODE=1 ;;
    *) echo "error: unknown argument '$arg' (only --override is recognized)" >&2; exit 2 ;;
  esac
done

# jq is required for emitting the structured JSON contract documented
# above. Without this early gate the script would die at the final jq
# invocation with `jq: command not found` and the agent parsing our
# stdout would have nothing to work with. Hand-roll the missing-jq
# diagnostic so the failure still satisfies the contract — every
# other failure mode below depends on jq being present.
if ! command -v jq >/dev/null 2>&1; then
  override_json="false"
  (( OVERRIDE_MODE == 1 )) && override_json="true"
  cat <<EOF
{"ok": false, "override": ${override_json}, "failures": [{"check": "jq-installed", "reason": "jq is not installed; install with 'brew install jq' (macOS) or 'apt install jq' (Debian/Ubuntu) and re-run"}], "warnings": []}
EOF
  exit 1
fi

# If we're inside a git worktree, run from its root so the TEMPLATE path
# below resolves the same way regardless of the caller's cwd. If we're
# NOT in a worktree, the check_in_git_worktree step below will fail
# cleanly; don't exit here — we want to surface all preflight failures
# as structured JSON, not die early.
# Capture stderr, not `2>/dev/null`: git returns 128 for BOTH the ordinary
# not-a-repo case AND real faults (corrupt/unreadable repo, an unsafe-
# ownership refusal), so the exit code alone cannot tell them apart — the
# distinguisher is git's own message. `rev-parse --show-toplevel` on no repo
# emits the stable, decades-old sentinel "not a git repository"; any other
# 128 is a fault this preflight must surface, not treat as "just not in a
# repo". Matching that one fixed token is not the regex-trap
# (rules/script-delegation.md) — it is a documented tool sentinel, not
# free-form text.
repo_root=""
git_rc=0
git_err=""
git_err_file=$(mktemp) || {
  # Emit the JSON envelope + exit 1, not a stderr-only exit 2: a bare exit
  # here breaks the documented "single JSON object on stdout" contract for
  # wrappers that parse it (jq is guaranteed by the early guard).
  reason="mktemp failed — cannot capture git stderr; check TMPDIR is writable"
  override_bool="false"; (( OVERRIDE_MODE == 1 )) && override_bool="true"
  jq -nc --argjson override "$override_bool" --arg reason "$reason" \
    '{ok: false, override: $override, failures: [{check: "tmpdir-writable", reason: $reason}], warnings: []}'
  echo "preflight.sh: ${reason}" >&2
  exit 1
}
repo_root=$(git rev-parse --show-toplevel 2>"$git_err_file") || git_rc=$?
# Read only if readable (explicit branch, not `2>/dev/null` suppression), then
# clean up with a checked rm so a failed cleanup warns rather than aborting
# under this script's `set -e`.
if [[ -r "$git_err_file" ]]; then
  git_err=$(cat "$git_err_file")
fi
if ! rm -f "$git_err_file"; then
  echo "preflight.sh: warning: could not remove temp file ${git_err_file} — remove it by hand" >&2
fi
# rc 128 whose stderr carries the not-a-repo sentinel is the expected case:
# fall through, and check_in_git_worktree below reports it as structured
# JSON. Every other non-zero rc — and a 128 WITHOUT that sentinel — is a
# git fault surfaced here.
if [[ $git_rc -ne 0 ]] && ! { [[ $git_rc -eq 128 ]] && [[ "$git_err" == *"not a git repository"* ]]; }; then
  # Build the JSON with jq, never interpolation: `reason` embeds raw git
  # stderr, which can carry quotes/newlines that would break the parse (the
  # push_failure injection class). jq is guaranteed here — the missing-jq
  # guard near the top of this file exits before we reach this line — so the
  # documented single-JSON-object contract holds (rules/script-delegation.md).
  override_bool="false"
  (( OVERRIDE_MODE == 1 )) && override_bool="true"
  reason="git rev-parse --show-toplevel failed (rc=${git_rc}): ${git_err} — not the ordinary not-a-repo case; verify git is installed and the repository is readable (e.g. 'git status', check ownership/safe.directory), then re-run"
  jq -nc --argjson override "$override_bool" --arg reason "$reason" \
    '{ok: false, override: $override, failures: [{check: "git-usable", reason: $reason}], warnings: []}'
  echo "preflight.sh: ${reason}" >&2
  # exit 1, not 2: this is a populated `failures` result like every other
  # preflight check, so it stays inside the documented "0 if ok, 1 if any
  # check fails" contract — no new exit code for callers to learn.
  exit 1
fi
if [[ -n "$repo_root" ]]; then
  cd "$repo_root"
fi

if (( OVERRIDE_MODE == 1 )); then
  BRANCH="feat/upgrade-coding-policy-review"
else
  BRANCH="feat/add-coding-policy-review"
fi
TEMPLATE_DIR=".tessl/plugins/jbaruch/coding-policy/skills/install-reviewer/templates"
# `.md` shim on the marker and trigger source: tessl packaging ships only
# .md/.sh/.json/.py, so a `.yml` or extensionless template never reaches the
# installed plugin. scaffold.sh strips the shim when it writes the targets.
TEMPLATES=(
  "${TEMPLATE_DIR}/fleet-review-enabled.md"
  "${TEMPLATE_DIR}/review-trigger.yml.md"
  "${TEMPLATE_DIR}/copilot-instructions.md"
)
TARGETS=(
  ".github/fleet-review-enabled"
  ".github/workflows/review-trigger.yml"
  ".github/copilot-instructions.md"
)

declare -a failures=()
declare -a warnings=()

# Build the JSON object with jq, never string interpolation: a reason can
# carry raw command output (a version string, a git error), and a quote,
# backslash, or newline in it would break the `jq --argjson failures` parse
# at emit time and drop the whole documented JSON contract. jq escapes it.
push_failure() {
  failures+=("$(jq -nc --arg check "$1" --arg reason "$2" '{check: $check, reason: $reason}')")
}

push_warning() {
  warnings+=("$(jq -nc --arg check "$1" --arg reason "$2" '{check: $check, reason: $reason}')")
}

check_in_git_worktree() {
  git rev-parse --git-dir >/dev/null 2>&1 || \
    push_failure "in-git-worktree" "Not inside a git worktree — run the skill from the root of the consumer repo's git checkout"
}

check_origin_remote() {
  git remote get-url origin >/dev/null 2>&1 || \
    push_failure "origin-remote" "No git remote named 'origin' — add one with 'git remote add origin <url>' before re-running (the push step assumes origin exists)"
}

check_gh_installed() {
  command -v gh >/dev/null 2>&1 || \
    push_failure "gh-installed" "GitHub CLI not found on PATH — install from https://cli.github.com/"
}

check_gh_authenticated() {
  gh auth status >/dev/null 2>&1 || \
    push_failure "gh-authenticated" "GitHub CLI not authenticated — run 'gh auth login'"
}

check_templates_present() {
  local missing=()
  for t in "${TEMPLATES[@]}"; do
    [[ -f "$t" ]] || missing+=("$t")
  done
  if [[ ${#missing[@]} -gt 0 ]]; then
    push_failure "templates-present" "Template(s) not found: ${missing[*]} — run 'tessl install jbaruch/coding-policy' first"
  fi
}

check_branch_not_local() {
  # show-ref: 0 present, 1 absent (both expected), >1 a git fault surfaced
  # as its own failure rather than read as "absent, all clear"
  # (rules/error-handling.md — expected non-result vs tool failure).
  local rc=0
  git show-ref --verify --quiet "refs/heads/${BRANCH}" || rc=$?
  case "$rc" in
    0) push_failure "branch-not-local" "Local branch '${BRANCH}' already exists — delete with: git branch -d '${BRANCH}' (refuses if unmerged); or rename with: git branch -m '${BRANCH}' '${BRANCH}.bak' before re-running" ;;
    1) ;;  # absent: clean
    *) push_failure "branch-not-local" "'git show-ref refs/heads/${BRANCH}' failed (rc=${rc}) — cannot verify branch state; the repository may be unreadable, check 'git status' and re-run" ;;
  esac
}

check_branch_not_remote() {
  # ls-remote --exit-code: 0 present, 2 absent (both expected), other a
  # network/auth/tool fault surfaced rather than read as "absent".
  local rc=0
  git ls-remote --exit-code --heads origin "$BRANCH" >/dev/null 2>&1 || rc=$?
  case "$rc" in
    0) push_failure "branch-not-remote" "Remote branch 'origin/${BRANCH}' already exists — delete with 'git push origin --delete ${BRANCH}' or rename before re-running" ;;
    2) ;;  # absent on remote: clean
    *) push_failure "branch-not-remote" "'git ls-remote origin ${BRANCH}' failed (rc=${rc}) — cannot verify remote branch state; likely a network or auth issue, resolve and re-run" ;;
  esac
}

# Override-mode safety check: refuse to upgrade if the consumer has dirty
# working-tree state on any reviewer target the upgrade overwrites and stages
# (the review-codex.yml workflow, the .github/codex-review/* scripts, and
# .github/copilot-instructions.md). Each is overwritten wholesale, so a
# consumer's unrelated pending edits would be swept into the reviewer-upgrade
# commit. A never-tracked, not-yet-created target (fresh install/upgrade) has
# nothing to clobber and is not flagged. Mirrors how `git pull` refuses to
# overwrite uncommitted changes — forces the consumer to commit, stash, or
# remove the local content before the scaffold replaces their files. "Dirty"
# here covers four states the override could clobber:
#   - symlink at the target path (working or broken); refuse outright so
#     `cp`/compile/append never follows or replaces an unexpected link
#   - tracked file with staged or unstaged edits relative to HEAD
#   - untracked regular file at the target path (consumer hand-rolled a
#     reviewer that was never staged); without this case the override
#     would silently clobber an intentional local file
#   - tracked file deleted from the working tree (`rm` or `git rm`) but
#     still present at HEAD; without this case scaffold.sh re-creates
#     the file and silently clobbers the consumer's intentional removal.
# Classify a single target's working-tree state, echoing a short reason
# when it is one the scaffold/commit flow could clobber or wrongly stage,
# and nothing for a clean tracked file or a path that neither exists nor
# is tracked at HEAD. Pure inspection — no mutation, always exits 0.
classify_target_dirty() {
  local t="$1"
  # `-e` follows symlinks, so a broken symlink (target nonexistent)
  # returns false; `-L` is true for any symlink, broken or not. The OR
  # catches every form of "something is at this path".
  if [[ ! -e "$t" && ! -L "$t" ]]; then
    # Nothing at this path in the working tree. If HEAD still tracks one
    # there the consumer either `rm`'d it (missing from working tree,
    # present in index + HEAD) or `git rm`'d it (missing from working tree
    # AND index, still in HEAD). `git diff --diff-filter=D HEAD` catches
    # both because it compares HEAD against the working tree. `--quiet`
    # exits 0 when there's no diff and 1 when there is. Branch on the code:
    # 1 is "deleted vs HEAD" (the finding), but >1 is a real git fault, and
    # `if ! ...` would collapse both and mislabel the fault "tracked
    # deletion" (rules/error-handling.md — distinguish an expected
    # non-result from a tool failure).
    local d_rc=0 d_err
    d_err=$(git diff --quiet --diff-filter=D HEAD -- "$t" 2>&1) || d_rc=$?
    case "$d_rc" in
      0) ;;                       # no diff: not deleted
      1) echo "tracked deletion" ;;
      # rc >1: capture and surface git's own message; the reason disclaims
      # the dirty-target framing the caller's recovery text assumes, since a
      # git fault is not something you commit or stash away
      *) echo "git fault (not a local edit) — 'git diff' failed rc=${d_rc} on ${t}: ${d_err}; inspect the repo (git status, safe.directory/ownership)" ;;
    esac
    return 0
  fi
  if [[ -L "$t" ]]; then
    # Symlinks (working or broken) get their own diagnostic — falling
    # through to "untracked" would mislabel a broken symlink. scaffold.sh
    # refuses symlinks too; this just surfaces it earlier.
    echo "symlink target"
  elif git ls-files --error-unmatch -- "$t" >/dev/null 2>&1; then
    # Tracked: flag uncommitted edits vs HEAD. Same rc branch as the
    # deletion probe above — 1 is dirty (the finding), >1 is a git fault
    # that `if ! ...` would mislabel "uncommitted edits".
    local e_rc=0 e_err
    e_err=$(git diff --quiet HEAD -- "$t" 2>&1) || e_rc=$?
    case "$e_rc" in
      0) ;;                       # clean
      1) echo "uncommitted edits" ;;
      *) echo "git fault (not a local edit) — 'git diff' failed rc=${e_rc} on ${t}: ${e_err}; inspect the repo (git status, safe.directory/ownership)" ;;
    esac
  else
    # Untracked regular file at the target path.
    echo "untracked"
  fi
}

check_no_dirty_target_edits() {
  local dirty=() t reason
  for t in "${TARGETS[@]}"; do
    reason=$(classify_target_dirty "$t")
    [[ -n "$reason" ]] && dirty+=("$t ($reason)")
  done
  if [[ ${#dirty[@]} -gt 0 ]]; then
    push_failure "no-dirty-target-edits" "--override refuses to overwrite local changes in: ${dirty[*]} — commit, stash, restore, or remove these first, then re-run"
  fi
}

main() {
  check_in_git_worktree
  check_gh_installed
  # gh-cli-dependent checks only make sense if gh is present — otherwise they
  # emit follow-on failures that can't succeed until gh is installed first.
  if command -v gh >/dev/null 2>&1; then
    check_gh_authenticated
  fi
  check_templates_present
  # Remaining checks depend on a git worktree with origin; skip if either is missing
  # so we don't leak confusing git-error diagnostics on top of the real failures.
  if git rev-parse --git-dir >/dev/null 2>&1; then
    check_origin_remote
    if (( OVERRIDE_MODE == 1 )); then
      # Override mode: the upgrade branch may legitimately exist locally
      # (from a prior in-flight upgrade) or remotely (from an open
      # upgrade PR). Skip the branch-clear checks and instead refuse if
      # the consumer's working tree has uncommitted changes to the
      # target files we're about to replace.
      check_no_dirty_target_edits
    else
      # Install mode: the install branch must NOT already exist locally or
      # remotely — Step 2's overwrite refusal in the skill assumes a fresh
      # branch, and scaffold.sh refuses any pre-existing reviewer target.
      check_branch_not_local
      if git remote get-url origin >/dev/null 2>&1; then
        check_branch_not_remote
      fi
    fi
  fi

  local failures_json
  if [[ ${#failures[@]} -eq 0 ]]; then
    failures_json='[]'
  else
    failures_json="[$(IFS=,; echo "${failures[*]}")]"
  fi

  local warnings_json
  if [[ ${#warnings[@]} -eq 0 ]]; then
    warnings_json='[]'
  else
    warnings_json="[$(IFS=,; echo "${warnings[*]}")]"
  fi

  local ok="true"
  local rc=0
  if [[ ${#failures[@]} -gt 0 ]]; then
    ok="false"
    rc=1
  fi

  local override_json="false"
  (( OVERRIDE_MODE == 1 )) && override_json="true"

  jq -n --argjson ok "$ok" --argjson override "$override_json" --argjson failures "$failures_json" --argjson warnings "$warnings_json" \
    '{ok: $ok, override: $override, failures: $failures, warnings: $warnings}'

  # Per rules/script-delegation.md ("self-error-handling: exit non-zero on
  # failure, write a diagnostic message to stderr"), on failure also emit a
  # short diagnostic to stderr so a caller that only watches stderr notices
  # the failure rather than relying on structured-stdout parsing.
  if [[ $rc -ne 0 ]]; then
    echo "preflight: ${#failures[@]} precondition(s) failed — see the 'failures' array in stdout for recovery commands" >&2
  fi
  exit "$rc"
}

[[ "${BASH_SOURCE[0]}" == "${0}" ]] && main "$@"