#!/usr/bin/env bash
#
# Verify the .deb that `cargo tauri build` produced is a correct, installable
# native package — BEFORE the one-command installer starts handing it to people.
#
# WHY: install.sh prefers the .deb on every Debian/Ubuntu machine, but until now
# nothing had ever inspected it, let alone installed it. Its Depends line was
# entirely whatever tauri inferred, unread. The failure mode we're guarding is a
# user running install.sh and getting either an apt resolution error or an app
# that installs and then won't launch because a library it needs was never
# declared.
#
# Five checks, cheapest first:
#   1. Print the control file + contents — the generated metadata becomes ground
#      truth in the build log instead of an assumption.
#   2. Naming: the binary is /usr/bin/thoughtsync and the generated .desktop
#      entry's StartupWMClass matches it. The app used to identify itself three
#      different ways depending on install channel (issue 2075); this is what
#      keeps the .deb — the only channel whose entry Tauri generates for us —
#      from drifting away from the two we write by hand.
#   3. dpkg-shlibdeps: the canonical Debian answer for "what does this ELF
#      actually need". Compared against what the package declares.
#   4. Every declared dependency resolves to a real package in apt (catches a
#      typo in the hand-written list, which would break install for everyone).
#   5. If a docker CLI is present, install into a clean debian container — the
#      highest-fidelity check, since the build image already has the -dev
#      packages installed and so can't prove resolution on its own.
#
# Check 5 is opportunistic on purpose: the build image is not guaranteed to carry
# a docker CLI, and adding one at job time would violate "the image is the
# toolchain" (rule 5). Checks 1-4 are self-contained and always run.
set -euo pipefail

SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
REPO_ROOT="$(cd "$SCRIPT_DIR/../../.." && pwd)"
DEB_DIR="$REPO_ROOT/target/release/bundle/deb"

shopt -s nullglob
DEBS=("$DEB_DIR"/*.deb)
[ ${#DEBS[@]} -gt 0 ] || { echo "ERROR: no .deb under $DEB_DIR — did the tauri build run?" >&2; exit 1; }
DEB="${DEBS[0]}"
echo "==> Verifying $(basename "$DEB")"

WORK="$(mktemp -d)"
trap 'rm -rf "$WORK"' EXIT INT TERM

fail=0
note_fail() { echo "FAIL: $1" >&2; fail=1; }

# --- 1. control metadata + contents -----------------------------------------
echo
echo "--- control ---"
dpkg-deb -I "$DEB" | sed 's/^/    /'
echo "--- contents ---"
dpkg-deb -c "$DEB" | awk '{print $1, $6}' | sed 's/^/    /'

# Declared runtime deps, normalised: strip version constraints, split
# alternatives ("a | b" both count as declared), one package name per line.
declared="$(dpkg-deb -f "$DEB" Depends 2>/dev/null |
  tr ',|' '\n\n' | sed -E 's/\(.*\)//; s/^[[:space:]]*//; s/[[:space:]]*$//' |
  grep -v '^$' | sort -u || true)"
echo
echo "--- declared Depends ---"
printf '%s\n' "$declared" | sed 's/^/    /'

dpkg-deb -x "$DEB" "$WORK/root"
BIN="$(find "$WORK/root" -type f -path '*/bin/*' -print -quit)"
[ -n "$BIN" ] || { echo "ERROR: no binary found under */bin/ in the package" >&2; exit 1; }
echo "    (binary: ${BIN#"$WORK/root"})"

# --- 2. naming is consistent -------------------------------------------------
# CANON is the one name the app answers to everywhere: the binary, the CLI
# command, the icon, and the WM_CLASS the window reports. Hardcoded here on
# purpose — this literal IS the contract the three install channels are held to.
# Deliberately NOT asserted: the control file's `Package:` field, which is
# `thought-sync`. tauri-bundler derives it as kebab-case(productName) with no
# config override, so "ThoughtSync" splits at the hump. Fixing it would mean
# unpacking and rewriting the control archive on every build — a fragile step for
# a cosmetic gain on one uninstall command. Left as a known wart (issue 2075).
CANON="thoughtsync"

installed_bin="${BIN#"$WORK/root"}"
[ "$installed_bin" = "/usr/bin/$CANON" ] ||
  note_fail "binary is at $installed_bin, expected /usr/bin/$CANON (mainBinaryName in tauri.conf.json)."

# Tauri generates this entry from the binary name, so a mismatch means the config
# and the bundler have diverged — exactly the drift that made the app group under
# a different taskbar icon depending on how it was installed.
entry="$(find "$WORK/root/usr/share/applications" -name '*.desktop' -print -quit 2>/dev/null || true)"
if [ -z "$entry" ]; then
  note_fail "no .desktop entry in the package — the app would not appear in any menu."
else
  echo "--- desktop entry ($(basename "$entry")) ---"
  sed 's/^/    /' "$entry"
  wmclass="$(sed -n 's/^StartupWMClass=//p' "$entry" | head -1)"
  [ "$wmclass" = "$CANON" ] ||
    note_fail "StartupWMClass is '${wmclass:-<unset>}', expected '$CANON' — the taskbar icon will not group."
  # `%u`/`%U` field codes may follow, so match the first word only.
  exec_cmd="$(sed -n 's/^Exec=//p' "$entry" | head -1 | awk '{print $1}')"
  [ "$exec_cmd" = "$CANON" ] ||
    note_fail "Exec runs '${exec_cmd:-<unset>}', expected '$CANON'."
fi
[ "$fail" -eq 0 ] && echo "OK: binary, Exec and StartupWMClass all agree on '$CANON'."

# --- 3. what the ELF actually needs -----------------------------------------
if command -v dpkg-shlibdeps >/dev/null 2>&1; then
  # dpkg-shlibdeps insists on a debian/control in the working directory even with
  # -O (write to stdout); a stub is enough to let it do the ELF analysis.
  mkdir -p "$WORK/deb-stub/debian"
  printf 'Source: thoughtsync\n\nPackage: thoughtsync\nArchitecture: amd64\n' \
    >"$WORK/deb-stub/debian/control"
  # `|| true`: pipefail is on and dpkg-shlibdeps still exits non-zero on some
  # symbol warnings even with --ignore-missing-info. An empty result degrades to
  # "check skipped" below — it must not abort the whole verification.
  required="$(cd "$WORK/deb-stub" &&
    dpkg-shlibdeps -O --ignore-missing-info "$BIN" 2>/dev/null |
    sed -E 's/^shlibs:Depends=//' | tr ',' '\n' |
    sed -E 's/\(.*\)//; s/^[[:space:]]*//; s/[[:space:]]*$//' | grep -v '^$' | sort -u || true)"

  echo
  echo "--- required by the binary (dpkg-shlibdeps) ---"
  printf '%s\n' "$required" | sed 's/^/    /'

  # A package may be satisfied transitively — we deliberately declare only
  # webkit2gtk + gtk3 and let glib/cairo/pango/gdk-pixbuf/libsoup3 arrive through
  # them, so "required but not declared" is only a real problem if it's also
  # unreachable from the declared set. Ask apt for that closure.
  closure="$(apt-cache depends --recurse --no-recommends --no-suggests \
    --no-conflicts --no-breaks --no-replaces --no-enhances -i $declared 2>/dev/null |
    grep -E '^[a-zA-Z0-9]' | sed -E 's/[<>]//g' | sort -u || true)"

  if [ -z "$required" ]; then
    echo "WARN: dpkg-shlibdeps returned nothing — skipping the coverage check." >&2
  elif [ -z "$closure" ]; then
    echo "WARN: apt has no package index here — skipping the transitive-coverage check." >&2
  else
    for pkg in $required; do
      # Essential / required-priority packages (libc6, libgcc-s1 …) are present on
      # every Debian system by definition; declaring them is noise, not safety.
      prio="$(dpkg-query -W -f='${Priority} ${Essential}' "$pkg" 2>/dev/null || true)"
      case "$prio" in *required*|*important*|*yes*) continue ;; esac
      printf '%s\n' "$closure" | grep -qx "$pkg" && continue
      printf '%s\n' "$declared" | grep -qx "$pkg" && continue
      note_fail "$pkg is needed by the binary but is neither declared nor reachable from the declared deps."
    done
    [ "$fail" -eq 0 ] && echo "OK: every non-essential library the binary needs is covered."
  fi
else
  echo "WARN: dpkg-shlibdeps unavailable — skipping the ELF dependency check." >&2
fi

# --- 4. declared deps are real packages -------------------------------------
if apt-cache policy dpkg >/dev/null 2>&1 && [ -n "$(apt-cache policy dpkg 2>/dev/null)" ]; then
  for pkg in $declared; do
    if [ -z "$(apt-cache policy "$pkg" 2>/dev/null)" ]; then
      note_fail "declared dependency '$pkg' does not exist in apt — install would fail for every user."
    fi
  done
  [ "$fail" -eq 0 ] && echo "OK: every declared dependency exists in apt."
fi

# --- 5. clean-container install (opportunistic) -----------------------------
# The build image already has libwebkit2gtk-4.1-dev etc. installed, so installing
# here would pass no matter what we declared. Only a pristine container proves
# apt can actually resolve the package for a real user.
if command -v docker >/dev/null 2>&1 && docker info >/dev/null 2>&1; then
  echo
  echo "==> Clean-container install test (debian:bookworm)"
  if docker run --rm -v "$DEB:/tmp/$(basename "$DEB"):ro" debian:bookworm \
      sh -c "apt-get update -qq && apt-get install -y --no-install-recommends '/tmp/$(basename "$DEB")'"; then
    echo "OK: the .deb installs cleanly on a stock debian:bookworm."
  else
    note_fail "the .deb did NOT install on a stock debian:bookworm."
  fi
else
  echo
  echo "NOTE: no usable docker CLI — skipping the clean-container install test."
  echo "      Checks 1-3 above still gate the package; a real-machine install is the operator's confirm."
fi

echo
[ "$fail" -eq 0 ] && { echo "==> .deb verification passed."; exit 0; }
echo "==> .deb verification FAILED." >&2
exit 1