pikchr: add update script

  doCheck = true;

  passthru.updateScript = ./update.sh;

  meta = {

    description = "PIC-like markup language for diagrams in technical documentation";

    homepage = "https://pikchr.org";

#!/usr/bin/env nix-shell

#!nix-shell -i bash -p common-updater-scripts jq gawk

set -euo pipefail

nixpkgs="$(git rev-parse --show-toplevel)"

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

# Build and run nix-prefetch-fossil from the local nixpkgs

prefetch_fossil="$(nix-build "$nixpkgs" -A nix-prefetch-scripts --no-out-link 2>/dev/null)/bin/nix-prefetch-fossil"

echo "Fetching latest pikchr revision..." >&2

# Run nix-prefetch-fossil and capture output

output=$("$prefetch_fossil" https://pikchr.org/home trunk 2>&1)

# Extract JSON from output (it's at the end after the blank line)

json_output=$(echo "$output" | gawk '/^{/{p=1} p')

# Extract revision, hash, and date

full_rev=$(echo "$json_output" | jq -r '.rev')

new_rev="${full_rev:0:16}"  # Use 16-char prefix for consistency

new_hash=$(echo "$json_output" | jq -r '.hash')

commit_date=$(echo "$json_output" | jq -r '.date')

# Fallback to current date if extraction fails

if [ -z "$commit_date" ] || [ "$commit_date" = "null" ]; then

    commit_date=$(date +%Y-%m-%d)

fi

new_version="0-unstable-$commit_date"

echo "Updating pikchr to $new_version (rev $new_rev)" >&2

# Use update-source-version from the nixpkgs root

(

    cd "$nixpkgs"

    update-source-version pikchr "$new_version" "$new_hash" \

        --file="pkgs/by-name/pi/pikchr/package.nix" \

        --rev="$new_rev"

)