#!/bin/bash

set -eu

# Ensure cargo-edit is installed
which cargo-set-version > /dev/null || cargo install cargo-edit

# Ensure we're in a clean state on an up-to-date `main` branch.
if [[ -n $(git status --short --untracked-files=no) ]]; then
  echo "Can't roll the railcars with uncommitted changes"
  exit 1
fi
if [[ $(git rev-parse --abbrev-ref HEAD) != "main" ]]; then
  echo "Run this command on the main branch"
  exit 1
fi
git pull -q --ff-only origin main
git fetch --tags

# Parse the current version
version=$(script/get-crate-version zed)
major=$(echo $version | cut -d. -f1)
minor=$(echo $version | cut -d. -f2)
patch=$(echo $version | cut -d. -f3)
prev_minor=$(expr $minor - 1)
next_minor=$(expr $minor + 1)

minor_branch_name="v${major}.${minor}.x"
prev_minor_branch_name="v${major}.${prev_minor}.x"
next_minor_branch_name="v${major}.${next_minor}.x"
preview_tag_name="v{major}.{minor}.{patch}-pre"

function cleanup {
  git checkout -q main
}
trap cleanup EXIT

echo "Checking invariants before taking any actions..."
if [[ $patch != 0 ]]; then
  echo "patch version on main should be zero"
  exit 1
fi
if [[ $(cat crates/zed/RELEASE_CHANNEL) != dev ]]; then
  echo "release channel on main should be dev"
  exit 1
fi
if git show-ref --quiet refs/tags/${preview_tag_name}; then
  echo "tag ${preview_tag_name} already exists"
  exit 1
fi
if git show-ref --quiet refs/heads/${minor_branch_name}; then
  echo "branch ${minor_branch_name} already exists"
  exit 1
fi
if ! git show-ref --quiet refs/heads/${prev_minor_branch_name}; then
  echo "previous branch ${minor_branch_name} doesn't exist"
  exit 1
fi
if [[ $(git show ${prev_minor_branch_name}:crates/zed/RELEASE_CHANNEL) != preview ]]; then
  echo "release channel on branch ${prev_minor_branch_name} should be preview"
  exit 1
fi

echo "Promoting existing branch ${prev_minor_branch_name} to stable..."
git checkout -q ${prev_minor_branch_name}
git clean -q -dff
stable_tag_name="v$(script/get-crate-version zed)"
if git show-ref --quiet refs/tags/${stable_tag_name}; then
  echo "tag ${preview_tag_name} already exists"
  exit 1
fi
old_prev_minor_sha=$(git rev-parse HEAD)
echo -n stable > crates/zed/RELEASE_CHANNEL
git commit -q --all --message "Stable ${prev_minor_branch_name}"
git tag ${stable_tag_name}

echo "Creating new preview branch ${minor_branch_name}..."
git checkout -q -b ${minor_branch_name}
echo -n preview > crates/zed/RELEASE_CHANNEL
git commit -q --all --message "Preview ${minor_branch_name}"
git tag ${preview_tag_name}

echo "Preparing main for version ${next_minor_branch_name}..."
git checkout -q main
git clean -q -dff
old_main_sha=$(git rev-parse HEAD)
cargo set-version --package zed --bump minor
cargo check -q
git commit -q --all --message "Dev ${next_minor_branch_name}"

cat <<MESSAGE
Locally rolled the railcars.

To push this:
    git push origin \\
      ${preview_tag_name} \\
      ${stable_tag_name} \\
      ${minor_branch_name} \\
      ${prev_minor_branch_name} \\
      main

To undo this:
    git push -f . \\
      :${preview_tag_name} \\
      :${stable_tag_name} \\
      :${minor_branch_name} \\
      ${old_prev_minor_sha}:${prev_minor_branch_name} \\
      ${old_main_sha}:main
MESSAGE