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

# Recorded in $DEST/VERSION only — the archive itself is fetched by the `main`
# label, since the archive URL uses a plugin-version coordinate that cannot be
# reconstructed from the commit alone.
SCHEMA_COMMIT="${1:?usage: regen.sh <schema-commit>}"

# Transitive deps. Buf does not expose pinned versions for these from the
# openstatus/api module, so we track main. The PHP plan ships empty initOnce()
# stubs for these; in Python we vendor the real generated modules — they are
# pure annotation/descriptor protos with no runtime impact on JSON transport.
readonly BUF_VALIDATE_REF="bufbuild/protovalidate"
readonly GNOSTIC_REF="gnostic/gnostic"

ARCHIVE_BASE="https://buf.build/gen/archive"
ROOT="$(cd "$(dirname "$0")/.." && pwd)"
DEST="${ROOT}/src/openstatus/_gen"
TMP="$(mktemp -d)"
trap 'rm -rf "$TMP"' EXIT

rm -rf "$DEST"
mkdir -p "$DEST"

fetch() {
    # fetch <buf-ref> <plugin> <pinned-or-main> <local-name>
    local ref="$1" plugin="$2" version="$3" name="$4"
    local url="${ARCHIVE_BASE}/${ref}/protocolbuffers/${plugin}/${version}.zip"
    echo "Fetching ${ref} ${plugin} ${version}..."
    curl -fsSL -L "$url" -o "${TMP}/${name}-${plugin}.zip"
    mkdir -p "${TMP}/${name}-${plugin}"
    unzip -q "${TMP}/${name}-${plugin}.zip" -d "${TMP}/${name}-${plugin}"
}

fetch "openstatus/api"        python main openstatus
fetch "openstatus/api"        pyi    main openstatus
fetch "${BUF_VALIDATE_REF}"   python main bufvalidate
fetch "${BUF_VALIDATE_REF}"   pyi    main bufvalidate
fetch "${GNOSTIC_REF}"        python main gnostic
fetch "${GNOSTIC_REF}"        pyi    main gnostic

# Merge a top-level package from a buf archive into $DEST.
#   - archive layout: <archive>/<plugin-prefix>_<lang>/<pkg-root>/...
#     e.g. openstatus-python/api_python/openstatus, bufvalidate-python/protovalidate_python/buf
merge() {
    local archive_dir="$1" pkg_root="$2"
    local src
    src="$(find "${TMP}/${archive_dir}" -type d -name "${pkg_root}" -maxdepth 3 | head -1)"
    if [[ -z "$src" ]]; then
        echo "ERROR: could not locate '${pkg_root}' tree inside ${archive_dir}" >&2
        find "${TMP}/${archive_dir}" -maxdepth 3 -type d >&2
        exit 1
    fi
    # tar pipe preserves dir merges (rsync-style) without depending on rsync.
    ( cd "$(dirname "$src")" && tar cf - "$(basename "$src")" ) | ( cd "$DEST" && tar xf - )
}

merge openstatus-python  openstatus
merge openstatus-pyi     openstatus
merge bufvalidate-python buf
merge bufvalidate-pyi    buf
merge gnostic-python     gnostic
merge gnostic-pyi        gnostic

# The generated *.py and *.pyi files use absolute imports
# (`from openstatus...`, `from buf...`, `from gnostic...`). Rewrite them to
# resolve under our private `openstatus._gen.*` namespace so the public
# `openstatus` package is not polluted and so the buf/gnostic vendored copies
# do not collide with any user-installed packages of the same name.
find "$DEST" -type f \( -name '*.py' -o -name '*.pyi' \) -print0 \
    | xargs -0 sed -i \
        -e 's|^from openstatus\.|from openstatus._gen.openstatus.|g' \
        -e 's|^from buf\.|from openstatus._gen.buf.|g' \
        -e 's|^from gnostic\.|from openstatus._gen.gnostic.|g' \
        -e 's|^import openstatus\.|import openstatus._gen.openstatus.|g' \
        -e 's|^import buf\.|import openstatus._gen.buf.|g' \
        -e 's|^import gnostic\.|import openstatus._gen.gnostic.|g'

# Generated trees ship no __init__.py — create empty shims so packages import.
find "$DEST" -type d -exec sh -c 'touch "$0/__init__.py"' {} \;

echo "${SCHEMA_COMMIT}" > "$DEST/VERSION"

echo
echo "Done. Generated tree at $DEST"
echo "Schema commit recorded at $DEST/VERSION"