#!/usr/bin/env bash

# updates changelog version indicated by release-plz

set -eEuo pipefail

### START HELPERS

function bump_changelog_version() {
    local package_dir="$1"
    local version="$2"

    local cargo_manifest="${package_dir}/Cargo.toml"
    local current_version="$(sed -nE 's/^version ?= ?"([^"]+)"$/\1/ p' "$cargo_manifest" | head -n 1)"
    local changelog_file="${package_dir}/CHANGELOG.md"
    local change_chunk_file="$(mktemp)"
    local readme_file="${package_dir}/README.md"

    echo "${package_dir}/CHANGELOG.md | $current_version -> $version"

    # get changelog chunk and save to temp file
    cat "$changelog_file" |
        # skip up to unreleased heading
        sed '1,/Unreleased/ d' |
        # take up to previous version heading
        sed "/$current_version/ q" |
        # drop last line
        sed '$d' \
            >"$change_chunk_file"

    # if word count of changelog chunk is 0 then insert filler changelog chunk
    if [[ "$(wc -w "$change_chunk_file" | awk '{ print $1 }')" == "0" ]]; then
        echo >"$change_chunk_file"
        echo "- No significant changes since \`$current_version\`." >>"$change_chunk_file"
        echo >>"$change_chunk_file"
    fi

    (
        sed '/Unreleased/ q' "$changelog_file"                   # up to unreleased heading
        echo                                                     # blank line
        echo "## $version"                                       # new version heading
        cat "$change_chunk_file"                                 # previously unreleased changes
        sed "/$current_version/ q" "$changelog_file" | tail -n 1 # the previous version heading
        sed "1,/$current_version/ d" "$changelog_file"           # everything after previous version heading
    ) >"$changelog_file.bak"

    mv "$changelog_file.bak" "$changelog_file"

    # update readme links
    if [ -f "$readme_file" ]; then
        sed -i.bak -E "s#([=/])$current_version([/)])#\1$version\2#g" "$readme_file"
        rm -f "${readme_file}.bak"
    fi
}

### END HELPERS

RELEASE_PLZ_PR_JSON="$1"

specs="$(echo "$RELEASE_PLZ_PR_JSON" | jq -r '.releases[] | "\(.package_name):\(.version)"')"

for spec in $specs; do
    name="$(echo "$spec" | cut -d: -f1)"
    version="$(echo "$spec" | cut -d: -f2)"
    
    bump_changelog_version "." "$version"
done

PR_NUMBER="$(echo "$RELEASE_PLZ_PR_JSON" | jq -r '.number')"

# update release PR if one was created
if [[ -n "$PR_NUMBER" ]]; then
    gh pr checkout "$PR_NUMBER"
    git add --all
    git commit -m "docs: update changelog versions"
    git push
fi