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

# Download the AWS Smithy service models used by internal/awsmodel from
# github.com/aws/api-models-aws at one pinned commit, gzip them into
# internal/awsmodel/models/ and record the commit in model_source.go.
# Usage: scripts/sync-aws-models.sh <commit-sha>

COMMIT="${1:?Usage: sync-aws-models.sh <commit-sha>}"
if [[ ! "$COMMIT" =~ ^[0-9a-f]{40}$ ]]; then
    echo "ERROR: commit must be a full 40-character SHA, got '$COMMIT'" >&2
    exit 1
fi

ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
PKG="$ROOT/internal/awsmodel"
OUT="$PKG/models"
REPO="https://github.com/aws/api-models-aws.git"

# <api-models-aws sdk-id>/<api version>
MODELS=(
    acm/2015-12-08
    ec2/2016-11-15
    ecr/2015-09-21
    ecs/2014-11-13
    eks/2017-11-01
    elastic-load-balancing-v2/2015-12-01
    iam/2010-05-08
    rds/2014-10-31
    s3/2006-03-01
    sts/2011-06-15
)

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

# A blobless shallow fetch pulls only the ten files read below.
git -C "$TMP" init --quiet repo
git -C "$TMP/repo" fetch --quiet --depth=1 --filter=blob:none "$REPO" "$COMMIT"
COMMITTED="$(git -C "$TMP/repo" log -1 --format=%cs "$COMMIT")"

for entry in "${MODELS[@]}"; do
    sdk_id="${entry%%/*}"
    version="${entry##*/}"
    file="$sdk_id-$version.json"
    echo "fetching $sdk_id $version"
    git -C "$TMP/repo" show "$COMMIT:models/$sdk_id/service/$version/$file" > "$TMP/$file"
    # -n omits the name and timestamp so re-running at one commit is a no-op.
    gzip -n -9 --stdout "$TMP/$file" > "$TMP/$file.gz"
done

mkdir -p "$OUT"
rm -f "$OUT"/*.json.gz
mv "$TMP"/*.json.gz "$OUT"/

cat > "$PKG/model_source.go" <<EOF
// Code generated by scripts/sync-aws-models.sh. DO NOT EDIT.

package awsmodel

// ModelCommit is the github.com/aws/api-models-aws commit the embedded
// models were taken from, and ModelCommitDate the day it was committed.
const (
	ModelCommit     = "$COMMIT"
	ModelCommitDate = "$COMMITTED"
)
EOF

echo "wrote ${#MODELS[@]} models at $COMMIT ($COMMITTED) to $OUT"