import "server-only";

import { analyzeTextLayerPixels, normalizeHexColor } from "@/lib/agents/psd-text-layout";
import {
  isAgentPsdTextLayerSlot,
  type AgentPsdTemplate,
  type AgentPsdTemplateTextLayerSlot,
} from "@/lib/agents/psd-template-config";
import { resolveAgentPsdLocalCachePath } from "@/lib/agents/psd-local-cache";
import { loadPsdTemplateSource } from "@/lib/agents/psd-template-parser";

function getEstimatedFontSize(height: number) {
  return Math.max(16, Math.min(height, Math.round(height * 0.78)));
}

function shouldRepairAutoTextLayer(layer: AgentPsdTemplateTextLayerSlot) {
  return layer.styleSource !== "custom";
}

function shouldPreferDetectedFontMetrics(
  layer: AgentPsdTemplateTextLayerSlot,
  detectedFontSize?: number
) {
  if (!Number.isFinite(detectedFontSize) || Number(detectedFontSize) <= 0) {
    return false;
  }

  const safeDetectedFontSize = Number(detectedFontSize);
  const fallbackEstimatedFontSize = getEstimatedFontSize(layer.height);
  const currentFontSize = Math.max(10, Number(layer.fontSize || 10));
  const relativeDiff =
    Math.abs(currentFontSize - safeDetectedFontSize) / Math.max(1, safeDetectedFontSize);

  return (
    shouldRepairAutoTextLayer(layer) &&
    (Math.abs(currentFontSize - fallbackEstimatedFontSize) <= 2 || relativeDiff > 0.16)
  );
}

async function getPixelAnalysis(
  cache: Map<string, Promise<ReturnType<typeof analyzeTextLayerPixels>>>,
  layerId: string,
  loadRgba: () => Promise<Uint8ClampedArray>,
  width: number,
  height: number
) {
  if (!cache.has(layerId)) {
    cache.set(
      layerId,
      loadRgba()
        .then((rgba) => analyzeTextLayerPixels({ rgba, width, height }))
        .catch(() => null)
    );
  }

  return cache.get(layerId)!;
}

export async function resolveAgentPsdTemplateTextStyles(template: AgentPsdTemplate) {
  const autoTextLayers = template.layers.filter(
    (layer): layer is AgentPsdTemplateTextLayerSlot =>
      isAgentPsdTextLayerSlot(layer) && shouldRepairAutoTextLayer(layer)
  );

  if (autoTextLayers.length === 0) {
    return template;
  }

  const source = await loadPsdTemplateSource({
    fileUrl: template.fileUrl,
    filePath: resolveAgentPsdLocalCachePath({
      templateId: template.id,
      fileName: template.fileName,
    }),
  });
  const sourceLayerMap = new Map(source.layers.map((entry) => [entry.layer.layerId, entry]));
  const pixelAnalysisCache = new Map<
    string,
    Promise<ReturnType<typeof analyzeTextLayerPixels>>
  >();

  let didChange = false;

  const nextLayers = await Promise.all(
    template.layers.map(async (layer) => {
      if (!isAgentPsdTextLayerSlot(layer) || !shouldRepairAutoTextLayer(layer)) {
        return layer;
      }

      const sourceEntry = sourceLayerMap.get(layer.layerId);
      if (!sourceEntry) {
        return layer;
      }

      let nextLayer = layer;

      if (shouldPreferDetectedFontMetrics(layer, sourceEntry.layer.detectedFontSize)) {
        nextLayer = {
          ...nextLayer,
          fontSize: Math.max(10, Math.round(Number(sourceEntry.layer.detectedFontSize || nextLayer.fontSize))),
          lineHeight:
            Number.isFinite(Number(sourceEntry.layer.detectedLineHeight)) &&
            Number(sourceEntry.layer.detectedLineHeight) > 0
              ? Number(sourceEntry.layer.detectedLineHeight)
              : nextLayer.lineHeight,
          letterSpacing: Number.isFinite(Number(sourceEntry.layer.detectedLetterSpacing))
            ? Number(sourceEntry.layer.detectedLetterSpacing)
            : nextLayer.letterSpacing,
        };
      }

      const needsColorRepair = normalizeHexColor(nextLayer.textColor) === "#111111";
      const needsAlignRepair = nextLayer.textAlign === "left";

      if (needsColorRepair && sourceEntry.layer.detectedTextColor) {
        nextLayer = {
          ...nextLayer,
          textColor: sourceEntry.layer.detectedTextColor,
        };
      }

      if (needsColorRepair || needsAlignRepair) {
        const analysis = await getPixelAnalysis(
          pixelAnalysisCache,
          layer.layerId,
          () => sourceEntry.composite(),
          sourceEntry.layer.width,
          sourceEntry.layer.height
        );

        if (
          analysis?.dominantColor &&
          normalizeHexColor(nextLayer.textColor) === "#111111"
        ) {
          nextLayer = {
            ...nextLayer,
            textColor: analysis.dominantColor,
          };
        }

        if (
          analysis?.inferredTextAlign &&
          needsAlignRepair &&
          analysis.inferredTextAlign !== nextLayer.textAlign
        ) {
          nextLayer = {
            ...nextLayer,
            textAlign: analysis.inferredTextAlign,
          };
        }

        if (
          Number(nextLayer.paddingX || 0) <= 0 &&
          Number.isFinite(Number(analysis?.suggestedPaddingX)) &&
          Number(analysis?.suggestedPaddingX) > 0
        ) {
          nextLayer = {
            ...nextLayer,
            paddingX: Math.max(0, Number(analysis?.suggestedPaddingX)),
          };
        }

        if (
          Number(nextLayer.paddingY || 0) <= 0 &&
          Number.isFinite(Number(analysis?.suggestedPaddingY)) &&
          Number(analysis?.suggestedPaddingY) > 0
        ) {
          nextLayer = {
            ...nextLayer,
            paddingY: Math.max(0, Number(analysis?.suggestedPaddingY)),
          };
        }
      }

      if (nextLayer !== layer) {
        didChange = true;
      }

      return nextLayer;
    })
  );

  return didChange
    ? {
        ...template,
        layers: nextLayers,
      }
    : template;
}