generate

#!/usr/bin/env bash
# Usage: generate [--commit] MODELS
#
# Runs amazonka-gen on the specified MODELS - which are directory names of the
# services definitions in https://github.com/boto/botocore/tree/develop/botocore/data/<MODEL>.
#
# Generates the output per MODEL in a temporary directory, formats .cabal and
# .hs files, removes the related amazonka-*/gen directories, and finally
# replaces the amazonka-*/gen contents with the updated sources.
#
# If --commit is the first argument a commit will be created per service directory.

set -euo pipefail

cd "$(dirname "${BASH_SOURCE[0]}")/.."

# Output a message to stderr.
say() {
	echo >&2 "$@"
}

commit="false"

case "${1-}" in
--commit)
	if [[ "$(git diff --stat)" != "" ]]; then
		say "Unable to use --commit when the git working tree is dirty."
		exit 1
	fi

	commit="true"
	shift
	;;
esac

# Format new sources in tmp and replace the corresponding amazonka-*/gen
# directory in the source tree if successful.
format_and_replace() {
	local -r dir="$1"

	say "Formatting $dir"

	find "$dir" -type f -name '*.cabal' -print0 |
		xargs -0 cabal-fmt --inplace --indent=2

	find "$dir" -type f \( -name '*.hs' -o -name '*.hs-boot' \) \
		-exec ormolu --mode=inplace \
		--ghc-opt='-XPatternSynonyms' \
		--ghc-opt='-XTypeApplications' \
		{} \+

	# Delete corresponding amazonka-*/gen dirs from the source tree.
	rm -rf "./lib/services/$(basename "$dir")/gen"

	# Copy formatted sources from tmp to the source tree.
	cp -R "$dir" lib/services
}

# Export the functions for use in GNU parallel.
export -f say
export -f format_and_replace

botocore="${BOTOCORE:?}/botocore/data"
models=()

if [ $# -eq 0 ]; then
	for model in configs/services/*.json; do
		models+=("$(basename "$model" .json)")
	done
else
	models=("$@")
fi

tmp="$(mktemp -d -p "$PWD")"

trap 'rm -rf "$tmp"' EXIT

say "Using botocore $botocore"
say "Using temporary directory $tmp"
say "Generating models ${models[*]}"

args=(
	--out="$tmp"
	--retry="${botocore}/_retry.json"
)

for model in "${models[@]}"; do
	args+=("${botocore}/${model}")
done

# Generate new sources in tmp.
nix run '.#gen' -- "${args[@]}"

# Run the format and copy/replace steps in parallel.
parallel --halt-on-error 2 format_and_replace ::: "$tmp"/amazonka-*

set +e

# If --commit was passed as the first argument, created a commit per service.
if [ "$commit" = "true" ]; then
	for service in lib/services/amazonka-*; do

		if git add "$service" >/dev/null 2>&1; then
			git commit --no-verify -m "$(basename "$service"): regenerating service"
		fi
	done
fi

say "Done."