module Streams
  module Overlay
    # PNG 1280×720 trasparente: tabellone alto-sinistra, badge alto-destra, brand sotto tabellone.
    class SvgBuilder
      CANVAS_W = 1280
      CANVAS_H = 720

      def initialize(session, badge:)
        @session = session
        @match = session.match
        @team = @match.team
        @score = session.score_state
        @badge = badge
      end

      def to_svg
        cols = score_columns
        <<~SVG
          <?xml version="1.0" encoding="UTF-8"?>
          <svg xmlns="http://www.w3.org/2000/svg" width="#{CANVAS_W}" height="#{CANVAS_H}" viewBox="0 0 #{CANVAS_W} #{CANVAS_H}">
            #{scorebug_svg(cols)}
            #{badge_svg}
          </svg>
        SVG
      end

      private

      def score_columns
        score = @score
        unless score
          return {
            labels: ["1"], home: ["0"], away: ["0"], home_name: abbrev(@match.team.name),
            away_name: abbrev(@match.opponent_name), sets_won: "0-0", current_set: 1
          }
        end

        partials = Array(score.set_partials)
        labels = partials.map { |p| p["set"].to_s }
        home = partials.map { |p| p["home"].to_s }
        away = partials.map { |p| p["away"].to_s }
        labels << score.current_set.to_s
        home << score.home_points.to_s
        away << score.away_points.to_s
        {
          labels: labels,
          home: home,
          away: away,
          home_name: abbrev(@match.team.name),
          away_name: abbrev(@match.opponent_name),
          sets_won: "#{score.home_sets}-#{score.away_sets}",
          current_set: score.current_set
        }
      end

      def scorebug_svg(cols)
        x0 = 12
        y0 = 12
        col_w = 26
        team_w = 118
        row_h = 18
        head_h = 16
        pad = 8
        n = cols[:labels].length
        box_w = team_w + n * col_w + pad * 2
        box_h = head_h + row_h * 2 + 22 + pad * 2
        live_i = n - 1
        home_primary = @team.effective_primary_color
        away_primary = Overlay.badge_away_color(@team)

        header_cells = cols[:labels].map.with_index do |label, i|
          cx = x0 + pad + team_w + i * col_w + col_w / 2
          "<text x=\"#{cx}\" y=\"#{y0 + pad + 12}\" text-anchor=\"middle\" font-family=\"DejaVu Sans, sans-serif\" font-size=\"10\" font-weight=\"700\" fill=\"#666666\">#{escape(label)}</text>"
        end.join

        home_pts = cols[:home].map.with_index do |val, i|
          cx = x0 + pad + team_w + i * col_w + col_w / 2
          y = y0 + pad + head_h + 14
          fill = i == live_i ? home_primary : "#111111"
          weight = i == live_i ? "900" : "800"
          bg = i == live_i ? "<rect x=\"#{cx - 12}\" y=\"#{y - 13}\" width=\"24\" height=\"16\" rx=\"3\" fill=\"#{home_primary}\" fill-opacity=\"0.14\"/>" : ""
          "#{bg}<text x=\"#{cx}\" y=\"#{y}\" text-anchor=\"middle\" font-family=\"DejaVu Sans, sans-serif\" font-size=\"13\" font-weight=\"#{weight}\" fill=\"#{fill}\">#{escape(val)}</text>"
        end.join

        away_pts = cols[:away].map.with_index do |val, i|
          cx = x0 + pad + team_w + i * col_w + col_w / 2
          y = y0 + pad + head_h + row_h + 14
          fill = i == live_i ? away_primary : "#111111"
          weight = i == live_i ? "900" : "800"
          bg = i == live_i ? "<rect x=\"#{cx - 12}\" y=\"#{y - 13}\" width=\"24\" height=\"16\" rx=\"3\" fill=\"#{away_primary}\" fill-opacity=\"0.14\"/>" : ""
          "#{bg}<text x=\"#{cx}\" y=\"#{y}\" text-anchor=\"middle\" font-family=\"DejaVu Sans, sans-serif\" font-size=\"13\" font-weight=\"#{weight}\" fill=\"#{fill}\">#{escape(val)}</text>"
        end.join

        <<~SVG
          <g id="scorebug">
            <rect x="#{x0}" y="#{y0}" width="#{box_w}" height="#{box_h}" rx="6" fill="#ffffff" fill-opacity="0.94"/>
            <line x1="#{x0 + pad}" y1="#{y0 + pad + head_h}" x2="#{x0 + box_w - pad}" y2="#{y0 + pad + head_h}" stroke="#000000" stroke-opacity="0.12"/>
            #{header_cells}
            <text x="#{x0 + pad}" y="#{y0 + pad + head_h + 14}" font-family="DejaVu Sans, sans-serif" font-size="12" font-weight="700" fill="#{home_primary}">#{escape(cols[:home_name])}</text>
            #{home_pts}
            <text x="#{x0 + pad}" y="#{y0 + pad + head_h + row_h + 14}" font-family="DejaVu Sans, sans-serif" font-size="12" font-weight="700" fill="#{away_primary}">#{escape(cols[:away_name])}</text>
            #{away_pts}
            <rect x="#{x0 + pad}" y="#{y0 + box_h - pad - 18}" width="#{box_w - pad * 2}" height="16" rx="4" fill="url(#brandGrad)"/>
            <text x="#{x0 + box_w / 2}" y="#{y0 + box_h - pad - 6}" text-anchor="middle" font-family="DejaVu Sans, sans-serif" font-size="9" font-weight="800" fill="#ffffff" letter-spacing="1.2">MATCH <tspan fill="#e53935">LIVE TV</tspan></text>
          </g>
          <defs>
            <linearGradient id="brandGrad" x1="0" y1="0" x2="1" y2="1">
              <stop offset="0%" stop-color="#14141c"/>
              <stop offset="55%" stop-color="#2a1214"/>
              <stop offset="100%" stop-color="#1a1a24"/>
            </linearGradient>
          </defs>
        SVG
      end

      def badge_svg
        text = @badge.text
        bg = @badge.background
        fg = @badge.foreground
        pad_x = 12
        pad_y = 6
        fs = 11
        tw = text.length * 6.5 + pad_x * 2
        th = fs + pad_y * 2
        x = CANVAS_W - 12 - tw
        y = 12
        <<~SVG
          <g id="badge">
            <rect x="#{x}" y="#{y}" width="#{tw}" height="#{th}" rx="#{th / 2}" fill="#{bg}"/>
            <text x="#{x + tw / 2}" y="#{y + th - pad_y - 1}" text-anchor="middle" font-family="DejaVu Sans, sans-serif" font-size="#{fs}" font-weight="700" fill="#{fg}" letter-spacing="0.5">#{escape(text)}</text>
          </g>
        SVG
      end

      def abbrev(name, max = 16)
        n = name.to_s
        n.length <= max ? n : "#{n[0, max - 1]}…"
      end

      def escape(str)
        str.to_s.gsub("&", "&amp;").gsub("<", "&lt;").gsub(">", "&gt;").gsub('"', "&quot;")
      end
    end
  end
end