#!/usr/bin/env bash
set -euo pipefail

function_path=$1
workdir=$(mktemp -d)
trap 'rm -rf "$workdir"' EXIT

export HOME="$workdir/home"
mkdir -p "$HOME"

git config --global user.email test@example.invalid
git config --global user.name 'Deploy Test'

origin="$workdir/origin.git"
repo="$workdir/repo"
ssh_log="$workdir/ssh.log"
mock_bin="$workdir/bin"

git init --bare "$origin" >/dev/null
git clone "$origin" "$repo" >/dev/null 2>&1

cd "$repo"
git switch -c impl/test >/dev/null
echo test >README.md
git add README.md
git commit -m 'test fixture' >/dev/null
git push -u origin impl/test >/dev/null 2>&1

mkdir -p "$mock_bin"
bash_path=${BASH_PATH:-$(command -v bash)}
cat >"$mock_bin/ssh" <<SSH
#!$bash_path
set -euo pipefail
printf '%s\n' "\$1" >"\$SSH_LOG"
printf '%s\n' "\$2" >>"\$SSH_LOG"
SSH
chmod +x "$mock_bin/ssh"

export SSH_LOG="$ssh_log"
export PATH="$mock_bin:$PATH"

fish_definition="function deploy-to; source '$function_path' \$argv; end"
default_command="$fish_definition; deploy-to pikachu"
explicit_command="$fish_definition; deploy-to pikachu impl/test"

fish -c "$default_command"

expected_command='cd ~/wrk/dotfiles && git fetch origin && git switch -- impl/test && git reset --hard origin/impl/test && sudo nixos-rebuild switch --flake .#pikachu --print-build-logs'

mapfile -t ssh_call <"$ssh_log"

test "${ssh_call[0]}" = pikachu
test "${ssh_call[1]}" = "$expected_command"

rm "$ssh_log"
fish -c "$explicit_command"
mapfile -t ssh_call <"$ssh_log"

test "${ssh_call[0]}" = pikachu
test "${ssh_call[1]}" = "$expected_command"

rm "$ssh_log"
echo dirty >>README.md

if fish -c "$default_command" 2>"$workdir/dirty.err"
then
    echo 'deploy-to unexpectedly allowed a dirty worktree' >&2
    exit 1
fi

grep -F 'dirty local worktree' "$workdir/dirty.err" >/dev/null

git checkout -- README.md

git commit --allow-empty -m 'unpushed fixture' >/dev/null

if fish -c "$default_command" 2>"$workdir/unpushed.err"
then
    echo 'deploy-to unexpectedly allowed a branch behind origin' >&2
    exit 1
fi

grep -F 'local HEAD differs from origin/impl/test' "$workdir/unpushed.err" >/dev/null