#!/usr/bin/env ruby
# frozen_string_literal: true

require "yaml"
require "faraday"
require "faraday/retry"
require "faraday/multipart"
require "listen"

CATEGORY_ID = ENV["DOCS_CATEGORY_ID"].to_i
DATA_EXPLORER_QUERY_ID = ENV["DOCS_DATA_EXPLORER_QUERY_ID"].to_i
DOCS_TARGET = ENV["DOCS_TARGET"]
DOCS_API_KEY = ENV["DOCS_API_KEY"]

VERBOSE = ARGV.include?("-v")
WATCH = ARGV.include?("--watch")
DRY_RUN = ARGV.include?("--dry-run")

require_relative "lib/local_doc"
require_relative "lib/api"
require_relative "lib/util"

docs = []

puts "Reading local docs..."
BASE = "#{__dir__}/docs/"
Dir
  .glob("**/*.md", base: BASE)
  .each do |path|
    next if path.end_with?("index.md")

    content = File.read(File.join(BASE, path))

    frontmatter, content = Util.parse_md(content)

    if frontmatter["id"].nil? || frontmatter["title"].nil?
      puts "Skipping '#{path}' because it has no id or title in frontmatter"
      next
    end

    docs.push(LocalDoc.new(frontmatter:, path:, content:))
  end

puts "Validating local docs..."
docs
  .group_by { |doc| doc.external_id }
  .each do |id, grouped_docs|
    if grouped_docs.size > 1
      puts "- duplicate external_id '#{id}' found in:"
      grouped_docs.each { |doc| puts "- #{doc.path}" }
      exit 1
    end
  end

exit 0 if !DOCS_API_KEY

puts "Fetching remote info via data-explorer..."
remote_topics = API.fetch_current_state

puts "Mapping to existing topics..."
map_to_remote =
  lambda do
    docs.each do |doc|
      puts "- checking '#{doc.external_id}'..." if VERBOSE
      if topic_info = remote_topics.find { |t| t[:external_id] == doc.external_id }
        doc.topic_id = topic_info[:topic_id]
        doc.first_post_id = topic_info[:first_post_id]
        doc.remote_title = topic_info[:title]
        doc.remote_content = topic_info[:raw]
        doc.remote_deleted = topic_info[:deleted_at]
        puts "  found topic_id: #{doc.topic_id}" if VERBOSE
      else
        puts " not found" if VERBOSE
      end
    end
  end
map_to_remote.call

puts "Deleting topics if necessary..."

cat_desc_topic = remote_topics.find { |t| t[:is_index_topic] }
if cat_desc_topic.nil?
  puts "Docs category is missing an index topic"
  exit 1
end
cat_desc_topic_id = cat_desc_topic[:topic_id]

remote_topics
  .reject { |remote_doc| remote_doc[:deleted_at] }
  .reject { |remote_doc| docs.any? { |doc| doc.topic_id == remote_doc[:topic_id] } }
  .reject { |remote_doc| remote_doc[:topic_id] == cat_desc_topic_id }
  .each do |remote_doc|
    id = remote_doc[:topic_id]
    puts "- deleting topic #{id}..."
    API.trash_topic(topic_id: id)
  end

puts "Restoring topics if necessary..."
docs
  .filter(&:remote_deleted)
  .each do |doc|
    puts "- restoring '#{doc.external_id}'..."
    API.restore_topic(topic_id: doc.topic_id)
  end

puts "Creating missing topics..."
created_any = false
docs.each do |doc|
  next if doc.topic_id

  created_any = true
  puts "- creating '#{doc.external_id}'"
  API.create_topic(
    external_id: doc.external_id,
    raw: doc.content_with_uploads,
    category: CATEGORY_ID,
    title: doc.frontmatter["title"]
  )
rescue Faraday::UnprocessableEntityError => e
  puts " 422 error: #{e.response[:body]}"
  raise e
end

if created_any
  puts "Re-fetching remote info..."
  remote_topics = API.fetch_current_state
  map_to_remote.call
end

puts "Updating content..."
docs.each do |doc|
  if doc.topic_id.nil?
    next if DRY_RUN
    raise "Topic ID not found for '#{doc.external_id}'. Something went wrong with creating it?"
  end

  if doc.content_with_uploads.strip == doc.remote_content.strip &&
       doc.frontmatter["title"] == doc.remote_title
    puts "- no changes required for '#{doc.external_id}' (topic_id: #{doc.topic_id})" if VERBOSE
    next
  end

  puts "- updating '#{doc.external_id}' (topic_id: #{doc.topic_id})..."
  API.edit_post(
    post_id: doc.first_post_id,
    raw: doc.content_with_uploads,
    title: doc.frontmatter["title"],
    category: CATEGORY_ID
  )
rescue Faraday::UnprocessableEntityError => e
  puts " 422 error: #{e.response[:body]}"
  raise e
end

puts "Building index..."
_, index_content = Util.parse_md(File.read("#{BASE}index.md"))
index_content += "\n\n"
docs
  .group_by { |doc| doc.section }
  .each do |section, section_docs|
    if section
      section_frontmatter, _ = Util.parse_md(File.read("#{BASE}#{section}/index.md"))
      index_content += "## #{section_frontmatter["title"]}\n\n"
    end

    section_docs.each do |doc|
      index_content +=
        "- #{doc.frontmatter["short_title"]}: [#{doc.frontmatter["title"]}](/t/-/#{doc.topic_id}?silent=true)\n"
    end
    index_content += "\n"
  end

index_post_info = remote_topics.find { |t| t[:topic_id] == cat_desc_topic_id }

if index_post_info[:raw].strip == index_content.strip
  puts "- no changes required for index"
else
  puts "- updating index..."
  API.edit_post(post_id: index_post_info[:first_post_id], raw: index_content)
end

if WATCH
  puts "Watching for changes to files..."

  Listen
    .to("#{__dir__}/docs") do |modified, added, removed|
      if added.size > 0 || removed.size > 0
        puts "Files added/removed. Restarting sync..."
        exec("ruby", "#{__dir__}/sync_docs", *ARGV)
      end

      modified.each do |path|
        relative = path.sub(BASE, "")
        doc = docs.find { |d| d.path == relative }
        raise "Modified file not recognized: #{relative}" if doc.nil?

        print "- updating '#{doc.external_id}' (topic_id: #{doc.topic_id})..."
        new_frontmatter, new_content = Util.parse_md(File.read(path))
        if %w[id short_title].any? { |key| doc.frontmatter[key] != new_frontmatter[key] }
          puts "Frontmatter changed. Restarting sync..."
          exec("ruby", "#{__dir__}/sync_docs", *ARGV)
        end
        doc.content, doc.frontmatter = new_content, new_frontmatter

        API.edit_post(
          post_id: doc.first_post_id,
          raw: doc.content_with_uploads,
          title: doc.frontmatter["title"]
        )
        puts " done"
      end
    end
    .start

  sleep
else
  puts "Done."
end