import { NextRequest, NextResponse } from "next/server";
import { z } from "zod";
import { auth } from "@/app/(auth)/auth";
import {
  getEditableAgentPsdTemplateLayers,
  getAgentPsdTemplateRuntimeIssue,
  isAgentPsdImageLayerSlot,
  isAgentPsdTemplateRuntimeReady,
  isAgentPsdTemplateReady,
  isAgentPsdTextLayerSlot,
  type AgentPsdTemplateRenderResponse,
} from "@/lib/agents/psd-template-config";
import { readAgentPsdFonts } from "@/lib/agents/psd-font-settings";
import { normalizeAgentPsdImagePlacement } from "@/lib/agents/psd-image-placement";
import { describeRemoteAssetLocation } from "@/lib/agents/psd-remote-asset";
import { repairAgentPsdTemplateFontBindings } from "@/lib/agents/psd-template-repair";
import { renderAgentPsdTemplate } from "@/lib/agents/psd-template-renderer";
import { normalizeHexColor } from "@/lib/agents/psd-text-layout";
import { readAgentPsdTemplates } from "@/lib/agents/psd-template-settings";

export const runtime = "nodejs";

const renderSchema = z.object({
  templateId: z.string().trim().min(1),
  sourceImageUrl: z.string().trim().optional().nullable(),
  imageAssignments: z.record(z.string(), z.string()).default({}),
  imagePlacements: z
    .record(
      z.string(),
      z.object({
        scale: z.number().positive().max(8).optional(),
        offsetX: z.number().optional(),
        offsetY: z.number().optional(),
      })
    )
    .default({}),
  textAssignments: z.record(z.string(), z.string()).default({}),
  textColorAssignments: z.record(z.string(), z.string()).default({}),
});

function jsonError(status: number, error: string) {
  const payload: AgentPsdTemplateRenderResponse = {
    success: false,
    error,
  };
  return NextResponse.json(payload, { status });
}

export async function POST(request: NextRequest) {
  const session = await auth().catch(() => null);
  if (!session?.user?.id) {
    return jsonError(401, "未登录");
  }

  let body: z.infer<typeof renderSchema>;
  try {
    body = renderSchema.parse(await request.json());
  } catch {
    return jsonError(400, "渲染参数不合法");
  }

  try {
    const templates = await readAgentPsdTemplates();
    const template = templates.find(
      (entry) =>
        entry.id === body.templateId &&
        entry.status === "active" &&
        isAgentPsdTemplateReady(entry)
    );

    if (!template) {
      return jsonError(404, "PSD 模板不存在或未启用");
    }

    const fonts = await readAgentPsdFonts();
    const resolvedTemplate = repairAgentPsdTemplateFontBindings(template, fonts);
    if (!isAgentPsdTemplateRuntimeReady(resolvedTemplate)) {
      return jsonError(
        409,
        getAgentPsdTemplateRuntimeIssue(resolvedTemplate) ||
          "PSD 模板资源不完整，请在后台重新解析后再导出"
      );
    }

    const editableLayers = getEditableAgentPsdTemplateLayers(resolvedTemplate);
    if (editableLayers.length === 0) {
      return jsonError(400, "当前模板未配置可编辑图层");
    }

    const fontMap = new Map(fonts.map((font) => [font.id, font]));
    const missingFontLayer = editableLayers.find(
      (layer) => isAgentPsdTextLayerSlot(layer) && layer.fontId && !fontMap.has(layer.fontId)
    );
    if (missingFontLayer) {
      return jsonError(400, `文字图层“${missingFontLayer.layerName}”引用的字体已不存在`);
    }

    const imageAssignments: Record<string, string> = {};
    const imagePlacements: Record<string, ReturnType<typeof normalizeAgentPsdImagePlacement>> = {};
    const textAssignments: Record<string, string> = {};
    const textColorAssignments: Record<string, string> = {};
    for (const layer of editableLayers) {
      if (isAgentPsdImageLayerSlot(layer)) {
        const explicitUrl = String(body.imageAssignments[layer.id] || "").trim();
        if (explicitUrl) {
          imageAssignments[layer.id] = explicitUrl;
          imagePlacements[layer.id] = normalizeAgentPsdImagePlacement(body.imagePlacements[layer.id]);
          continue;
        }

        if (layer.isDefaultResultSource && body.sourceImageUrl?.trim()) {
          imageAssignments[layer.id] = body.sourceImageUrl.trim();
          imagePlacements[layer.id] = normalizeAgentPsdImagePlacement(body.imagePlacements[layer.id]);
        }
      }

      if (isAgentPsdTextLayerSlot(layer)) {
        const nextText = String(body.textAssignments[layer.id] || layer.defaultText || "").trim();
        if (nextText) {
          textAssignments[layer.id] = nextText;
        }
        textColorAssignments[layer.id] = normalizeHexColor(
          body.textColorAssignments[layer.id] || layer.textColor,
          layer.textColor
        );
      }
    }

    const missingRequiredLayer = editableLayers.find(
      (layer) =>
        layer.isRequired &&
        (isAgentPsdImageLayerSlot(layer)
          ? !imageAssignments[layer.id]
          : !textAssignments[layer.id])
    );
    if (missingRequiredLayer) {
      return jsonError(400, `缺少必传素材：${missingRequiredLayer.layerName}`);
    }

    const uploaded = await renderAgentPsdTemplate({
      template: resolvedTemplate,
      imageAssignments,
      imagePlacements,
      textAssignments,
      textColorAssignments,
      fonts,
    });

    return NextResponse.json({
      success: true,
      result: {
        url: uploaded.url,
        pathname: uploaded.pathname,
        contentType: uploaded.contentType,
      },
    } satisfies AgentPsdTemplateRenderResponse);
  } catch (error) {
    console.error("[PSD Templates] render failed:", {
      templateId: body.templateId,
      sourceImage: body.sourceImageUrl
        ? describeRemoteAssetLocation(body.sourceImageUrl)
        : null,
      assignedImageCount: Object.keys(body.imageAssignments || {}).length,
      error,
    });
    const message =
      error instanceof Error && String(error.message || "").trim()
        ? error.message
        : "PSD 模板渲染失败";
    return jsonError(502, message);
  }
}