#!/usr/bin/env bash

# --- OPTIONS ---
declare -r NIXPKGS_PATH="$HOME/nixpkgs"
# See https://git.pvv.ntnu.no/oysteikt/nixpkgs-meta-dump
declare -r METADUMP="$(pwd)/result"
# ---------------

declare -r JQ_TRANSFORMATION='
[to_entries[]
  | select (.value.changelog == null)
	| { name: .key, url: .value.homepage, pos: .value.position }]
| map(select(.url != null))
| map(select(.url|type == "string"))
| map(select(.url | test("^https?://github.com.*")))
| .[].url |= sub("^https?://github.com/(?<x>.+/.+/?).*"; "\(.x)")
| .[]
'

declare -r RESULT=$(jq -c <"$METADUMP" "$JQ_TRANSFORMATION")
declare -r FZF_PREVIEW_COMMAND="
echo {} \
| jq -r '.url | \"repos/\\(.)\/releases\"' \
| xargs gh api \
| jq -r '[.[].body] | join(\"\n---------------------------------------------------------------------------\n\")'
"

CHOSEN_ENTRY=$(fzf <<<"$RESULT" --preview "$FZF_PREVIEW_COMMAND")

if [ "$CHOSEN_ENTRY" == "" ]; then
  exit 0
fi

declare -r PACKAGE_URL_PIECE=$(jq -r '.url' <<<"$CHOSEN_ENTRY")
declare -r NIXPKGS_REL_POSITION=$(jq -r '.pos' <<<"$CHOSEN_ENTRY" | sed -E -s 's|/nix/store/[0-9a-z]+-source/(.+?):[[:digit:]]+|\1|')
declare -r NIXPKGS_POSITION="$NIXPKGS_PATH/$NIXPKGS_REL_POSITION"

# Determine whether finalattrs or rec (or nothing atm)
# This could use some more work
if grep -q "finalAttrs" "$NIXPKGS_POSITION"; then
  export NVIM_CLIPBOARD="changelog = \"https://github.com/${PACKAGE_URL_PIECE}/releases/tag/\${finalAttrs.src.rev}\";"
else
  export NVIM_CLIPBOARD="changelog = \"https://github.com/${PACKAGE_URL_PIECE}/releases/tag/\${src.rev}\";"
fi

nvim "$NIXPKGS_POSITION"