# frozen_string_literal: true

require "json"
require "csv"

require_relative "./helper"
require_relative "./metrics"

module Danger
  class DangerComposeCompilerMetrics < Plugin
    include Helper

    def report_difference(metrics_dir, reference_metrics_dir, options = {})
      unless installed?("diff")
        failure "diff command not found. Please install diff command."
        return
      end

      markdown("# Compose Compiler Metrics Difference Report")
      build_variants(metrics_dir).each do |module_name, build_variant|
        markdown("## #{module_name} - #{build_variant}")

        # Metrics Report
        metrics_path = File.join(metrics_dir, metrics_filename(module_name, build_variant))
        reference_metrics_path = File.join(reference_metrics_dir, metrics_filename(module_name, build_variant))

        report_metrics_report("Metrics Summary", metrics_path, reference_metrics_path, options[:metrics_summary])
        report_file_difference("Metrics", metrics_path, reference_metrics_path, options[:metrics])

        # Composable Stats Report
        composable_stats_report_path = File.join(metrics_dir, composable_stats_report_path(module_name, build_variant))
        reference_composable_stats_report_path = File.join(reference_metrics_dir, composable_stats_report_path(module_name, build_variant))
        report_file_difference("Composable Stats Report", composable_stats_report_path, reference_composable_stats_report_path, options[:composable_stats])

        # Composable Report
        composable_report_path = File.join(metrics_dir, composable_report_path(module_name, build_variant))
        reference_composable_report_path = File.join(reference_metrics_dir, composable_report_path(module_name, build_variant))
        report_file_difference("Composable Report", composable_report_path, reference_composable_report_path, options[:composable_report])

        # Class Report
        class_report_path = File.join(metrics_dir, class_report_path(module_name, build_variant))
        reference_class_report_path = File.join(reference_metrics_dir, class_report_path(module_name, build_variant))
        report_file_difference("Class Report", class_report_path, reference_class_report_path, options[:class_report])
      end
    end

    def report_metrics_report(title, metrics_path, reference_metrics_path, open)
      open ||= :close
      return if open == :disabled

      unless File.exist?(metrics_path)
        warn "DangerComposeCompilerMetrics: new file not found at #{metrics_path}. Skipping file difference report."
        return
      end

      unless File.exist?(reference_metrics_path)
        warn "DangerComposeCompilerMetrics: reference file not found at #{reference_metrics_path}. Skipping file difference report."
        return
      end

      metrics = Metrics.load(metrics_path)
      reference_metrics = Metrics.load(reference_metrics_path)

      tables = reference_metrics.grouped_metrics.map do |group_key, grouped_reference_metrics|
        grouped_metrics = metrics.grouped_metrics[group_key]

        table_headers = %w(name reference new diff)
        table_rows = grouped_reference_metrics.keys.map do |key|
          new_value = grouped_metrics.send(key.to_sym)
          reference_value = grouped_reference_metrics.send(key.to_sym)
          diff_value = (new_value - reference_value).then do |v|
            next "+#{v}" if v.positive?

            next v.to_s if v.negative?

            ""
          end

          [key, reference_value, new_value, diff_value]
        end

        [
          "#### #{group_key}",
          build_markdown_table(table_headers, table_rows)
        ].join("\n\n")
      end

      markdown(
        folding(
          "### #{title}",
          tables.join("\n\n"),
          open
        )
      )
    end

    def report_file_difference(title, metrics_path, reference_metrics_path, open)
      open ||= :close
      return if open == :disabled

      unless File.exist?(metrics_path)
        warn "DangerComposeCompilerMetrics: new file not found at #{metrics_path}. Skipping file difference report."
        return
      end

      unless File.exist?(reference_metrics_path)
        warn "DangerComposeCompilerMetrics: reference file not found at #{reference_metrics_path}. Skipping file difference report."
        return
      end

      report = `diff -u #{reference_metrics_path} #{metrics_path}`

      markdown(
        folding(
          "### #{title}",
          if report.empty?
            "No difference found."
          else
            <<~MARKDOWN
            ```diff
            #{report}
            ```
            MARKDOWN
          end,
          open
        )
      )
    end

    def report(metrics_dir, options = {})
      markdown("# Compose Compiler Metrics Report")
      build_variants(metrics_dir).each do |module_name, build_variant|
        markdown("## #{module_name} - #{build_variant}")

        # Metrics Report
        metrics_path = File.join(metrics_dir, metrics_filename(module_name, build_variant))
        table_headers = %w(name value)
        table_rows = JSON.load_file(metrics_path).to_a
        report_table("Metrics", table_headers, table_rows, options[:metrics])

        # Composable Stats Report
        composable_stats_report_path = File.join(metrics_dir, composable_stats_report_path(module_name, build_variant))
        csv = CSV.read(composable_stats_report_path, headers: true)
        report_table("Composable Stats Report", csv.headers, csv.map(&:fields), options[:composable_stats])

        # Composable Report
        composable_report_path = File.join(metrics_dir, composable_report_path(module_name, build_variant))
        report_code_block("Composable Report", "kotlin", File.read(composable_report_path), options[:composable_report])

        # Class Report
        class_report_path = File.join(metrics_dir, class_report_path(module_name, build_variant))
        report_code_block("Class Report", "kotlin", File.read(class_report_path), options[:class_report])
      end
    end

    def report_table(title, headers, rows, open)
      return if open == :disabled

      markdown(
        folding(
          "### #{title}",
          build_markdown_table(headers, rows),
          open
        )
      )
    end

    def report_code_block(title, language, code, open)
      return if open == :disabled

      markdown(
        folding(
          "### #{title}",
          <<~MARKDOWN,
          ```#{language}
          #{code}
          ```
          MARKDOWN
          open
        )
      )
    end
  end
end