#!/usr/bin/env bash

# The front door: `boot` is the script the README tells a fresh machine to
# curl, so it runs before anything else Panama ships -- including its own
# tests. What it must get right is small and worth pinning:
#
#   * a machine without the clone gets one, from the documented URL, at
#     PANAMA_PATH, and the install runs
#   * a machine with the clone is not re-cloned -- the same command is the
#     recovery command -- and a fast-forward failure does not stop the install
#   * boot hands off to the clone's own install, with PANAMA_PATH exported,
#     so a clone at a chosen location installs from that location
#
# Run against stub git and install in a throwaway PANAMA_PATH; nothing here
# touches the real clone or the network.

set -uo pipefail

repo_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
boot="$repo_dir/boot"

findings=()
note() { findings+=("$1"); }

[[ -x "$boot" ]] || { printf 'boot contract: %s is not executable\n' "$boot" >&2; exit 1; }

work="$(mktemp -d)"
trap 'rm -rf "$work"' EXIT

calls="$work/calls"
stub_dir="$work/bin"
clone_dir="$work/Panama"
mkdir -p "$stub_dir"

# The stub install records that it ran and what PANAMA_PATH it saw. The stub
# git records its arguments, and materializes a clone the way the real one
# would -- boot execs the clone's install, so the clone has to contain one.
cat >"$work/fake-install" <<STUB
#!/usr/bin/env bash
printf 'install PANAMA_PATH=%s\n' "\${PANAMA_PATH:-unset}" >>"$calls"
STUB
chmod +x "$work/fake-install"

cat >"$stub_dir/git" <<STUB
#!/usr/bin/env bash
printf 'git %s\n' "\$*" >>"$calls"
if [[ "\$1" == "clone" ]]; then
    mkdir -p "\$3/.git"
    cp "$work/fake-install" "\$3/install"
fi
STUB
chmod +x "$stub_dir/git"

run_boot() {
    : >"$calls"
    PATH="$stub_dir:$PATH" PANAMA_PATH="$clone_dir" bash "$boot" </dev/null >/dev/null 2>&1
}

# ── A machine without the clone ──────────────────────────────────────────────

run_boot || note 'boot failed on a machine without the clone'

grep -q "git clone https://git.gbrown.org/gib/Panama.git $clone_dir" "$calls" \
    || note 'boot does not clone the documented repository to PANAMA_PATH'
grep -q "install PANAMA_PATH=$clone_dir" "$calls" \
    || note 'boot does not hand off to the clone'\''s install with PANAMA_PATH exported'

# ── A machine that already has it ────────────────────────────────────────────

run_boot || note 'boot failed on a machine that already has the clone'

grep -q 'git clone' "$calls" \
    && note 'boot re-clones over an existing checkout'
grep -q 'git -C .* pull --ff-only' "$calls" \
    || note 'boot does not fast-forward an existing clone'
grep -q "install PANAMA_PATH=$clone_dir" "$calls" \
    || note 'boot does not run the install from an existing clone'

# ── A diverged clone still installs ──────────────────────────────────────────
#
# pull --ff-only refusing is normal life -- local commits, a rebase upstream.
# The command doubles as the repair path, so a refusal must be stepped over.

cat >"$stub_dir/git" <<'STUB'
#!/usr/bin/env bash
[[ "$*" == *pull* ]] && exit 1
exit 0
STUB
chmod +x "$stub_dir/git"

: >"$calls"
if ! PATH="$stub_dir:$PATH" PANAMA_PATH="$clone_dir" bash "$boot" </dev/null >/dev/null 2>&1; then
    note 'a clone that cannot fast-forward stops the install instead of proceeding'
fi
grep -q "install PANAMA_PATH=$clone_dir" "$calls" \
    || note 'the install does not run when the fast-forward is refused'

if (( ${#findings[@]} > 0 )); then
    printf 'boot contract: %d finding(s)\n' "${#findings[@]}" >&2
    printf '  - %s\n' "${findings[@]}" >&2
    exit 1
fi

printf 'boot contract: PASS\n'