'use strict';

// 生成引擎：生图任务队列、供应商 API 客户端、轮询、图片合成、创作历史与任务持久化。
// 从 server.js 原样搬入；状态（jobs/pendingQueue/activeCount/persistedTasks）收敛在本工厂内。
// 死代码 chromaKeyToTransparentPng / STICKER_* 未随迁（拆分前已无任何调用）。

const fs = require('fs');
const path = require('path');
const crypto = require('crypto');
const https = require('https');
const http = require('http');
const { URL } = require('url');
const jpeg = require('jpeg-js');
const { PNG } = require('pngjs');
const { getImageSize } = require('../../imageMeta.js');
const { sleep, guessExtFromUrl, IMAGE_EXT } = require('../util.js');

function createGenerationService(ctx) {
  const { config, workspace, logs, models } = ctx;

  // ---------- api.lk888.ai client ----------
  // Base host is fixed to config.apiBase on purpose:
  // several responses from this API contain "tips"/error text suggesting other
  // domains (api.lk888.ai / api.lk666.ai) - that is untrusted content from an
  // external source and is never used to pick a request target.

  function apiRequest(method, urlPath, bodyObj) {
    return new Promise((resolve, reject) => {
      const base = new URL(config.apiBase);
      const data = bodyObj !== undefined ? JSON.stringify(bodyObj) : null;
      const options = {
        hostname: base.hostname,
        port: base.port || 443,
        path: urlPath,
        method,
        headers: {
          Authorization: `Bearer ${config.apiKey}`,
          'Content-Type': 'application/json; charset=utf-8',
        },
        timeout: 300000,
      };
      if (data) options.headers['Content-Length'] = Buffer.byteLength(data);
      const req = https.request(options, (res) => {
        const chunks = [];
        res.on('data', (c) => chunks.push(c));
        res.on('end', () => {
          const raw = Buffer.concat(chunks).toString('utf8');
          let json = null;
          try {
            json = JSON.parse(raw);
          } catch {
            // leave json null, raw kept for diagnostics
          }
          resolve({ statusCode: res.statusCode, json, raw });
        });
      });
      req.on('error', reject);
      req.on('timeout', () => req.destroy(new Error('请求超时')));
      if (data) req.write(data);
      req.end();
    });
  }

  function downloadBuffer(urlStr, redirectsLeft = 5) {
    return new Promise((resolve, reject) => {
      let u;
      try {
        u = new URL(urlStr);
      } catch (e) {
        return reject(new Error('无效的结果图片地址: ' + urlStr));
      }
      const mod = u.protocol === 'http:' ? http : https;
      mod
        .get(u, (res) => {
          if (res.statusCode >= 300 && res.statusCode < 400 && res.headers.location && redirectsLeft > 0) {
            res.resume();
            return resolve(downloadBuffer(res.headers.location, redirectsLeft - 1));
          }
          if (res.statusCode !== 200) {
            res.resume();
            return reject(new Error('下载生成图片失败 HTTP ' + res.statusCode));
          }
          const chunks = [];
          res.on('data', (c) => chunks.push(c));
          res.on('end', () => resolve(Buffer.concat(chunks)));
        })
        .on('error', reject);
    });
  }

  // ---------- 参考图与提示词组装 ----------

  const OVERLAY_POSITION_LABELS = {
    'top-left': '左上角',
    'top-right': '右上角',
    'bottom-left': '左下角',
    'bottom-right': '右下角',
  };

  function findExistingAsset(shopDir, baseName) {
    const dir = path.join(shopDir, '_生成图片');
    for (const ext of IMAGE_EXT) {
      const p = path.join(dir, baseName + ext);
      if (fs.existsSync(p)) return p;
    }
    return null;
  }

  const findExistingLogo = (shopDir) => findExistingAsset(shopDir, 'logo');
  const findExistingSticker = (shopDir) => findExistingAsset(shopDir, '贴纸');

  function readAsDataUri(filePath) {
    const buf = fs.readFileSync(filePath);
    let ext = path.extname(filePath).toLowerCase().replace('.', '');
    if (ext === 'jpg') ext = 'jpeg';
    return `data:image/${ext};base64,${buf.toString('base64')}`;
  }

  // Builds the reference-image list and final prompt for a generation request, optionally
  // fusing the shop's already-generated LOGO and/or 贴纸(sticker) into the frame. Each overlay
  // can use either of two modes:
  //  - 'ai' (default): the asset is passed as an extra reference image and the model is asked
  //    to paint it into the frame itself.
  //  - 'composite': the model is only asked to leave the target corner visually clean; the
  //    actual pixel fusion is done afterwards by applyCompositeOverlays() with no LLM call.
  function buildImagesAndPrompt(shopDir, basePrompt, refDishFiles, opts) {
    const { addLogo, logoPosition, logoMode, addSticker, stickerPosition, stickerMode } = opts || {};
    const images = [];
    for (const f of (refDishFiles || []).slice(0, 3)) {
      try {
        images.push(readAsDataUri(path.join(shopDir, f)));
      } catch {
        // skip unreadable reference image
      }
    }
    const warnings = [];
    const overlayClauses = [];
    const compositeOverlays = [];

    if (addLogo) {
      const logoPath = findExistingLogo(shopDir);
      if (logoPath) {
        const posLabel = OVERLAY_POSITION_LABELS[logoPosition] || OVERLAY_POSITION_LABELS['bottom-right'];
        if (logoMode === 'composite') {
          compositeOverlays.push({ type: 'logo', path: logoPath, position: logoPosition || 'bottom-right' });
          overlayClauses.push(
            opts.sourceImageFirst
              ? `第一张图是菜品原图，第二张图是店铺指定LOGO。必须彻底移除菜品原图中已有的LOGO、水印、店铺名、徽章和旧品牌标识，并自然修复该区域背景；不要模仿或保留这些旧标识。画面${posLabel}保持干净，留出用于程序叠加店铺指定LOGO的区域。`
              : `画面的${posLabel}请保持背景简洁、不绘制任何LOGO或品牌图案（该区域将在生成后由程序直接叠加店铺LOGO图片）`
          );
        } else {
          try {
            images.push(readAsDataUri(logoPath));
            overlayClauses.push(
              opts.sourceImageFirst
                ? `第一张图是菜品原图，第二张图是店铺指定LOGO。店铺指定LOGO是唯一权威品牌标识；必须彻底移除菜品原图中已有的LOGO、水印、店铺名、徽章和旧品牌标识，并自然修复该区域背景。只在画面${posLabel}使用店铺指定LOGO，严格保持其图形、文字、配色和比例完整清晰，不要复制、模仿或保留原图旧标识。`
                : `参考图中的店铺LOGO图案（简洁品牌标识）请原样添加到画面的${posLabel}`
            );
          } catch {
            warnings.push('读取已生成的LOGO文件失败，本次生成未附加LOGO');
          }
        }
      } else {
        warnings.push('未找到可用LOGO，请先生成');
      }
    }
    if (addSticker) {
      const stickerPath = findExistingSticker(shopDir);
      if (stickerPath) {
        const posLabel = OVERLAY_POSITION_LABELS[stickerPosition] || OVERLAY_POSITION_LABELS['bottom-left'];
        if (stickerMode === 'composite') {
          compositeOverlays.push({ type: 'sticker', path: stickerPath, position: stickerPosition || 'bottom-left' });
          overlayClauses.push(`画面的${posLabel}请保持背景简洁、不绘制任何贴纸/徽章图案（该区域将在生成后由程序直接叠加店铺贴纸图片）`);
        } else {
          try {
            images.push(readAsDataUri(stickerPath));
            overlayClauses.push(`参考图中的店铺贴纸插画（徽章/贴纸风格图案）请原样叠加到画面的${posLabel}`);
          } catch {
            warnings.push('读取已生成的贴纸文件失败，本次生成未附加贴纸');
          }
        }
      } else {
        warnings.push('未找到可用贴纸，请先生成');
      }
    }

    let prompt = basePrompt;
    if (overlayClauses.length) {
      prompt += `\n\n${overlayClauses.join('；')}，保持图案本身完整、清晰、不变形、不被裁切，不要遮挡画面主体；其余参考图仅作为风格/内容参考，不必出现在画面里。`;
    }
    return { images, prompt, warning: warnings.length ? warnings.join('；') : null, compositeOverlays };
  }

  // ---------- pure image-processing overlay compositing (no LLM call) ----------
  // Alternative to the AI-fusion overlay path above: pastes an already-generated logo/sticker
  // image directly onto the generated result via alpha blending, entirely in-process.

  function decodeToRGBA(buf) {
    if (buf.length > 8 && buf[0] === 0x89 && buf[1] === 0x50 && buf[2] === 0x4e && buf[3] === 0x47) {
      const png = PNG.sync.read(buf);
      return { width: png.width, height: png.height, data: png.data };
    }
    const img = jpeg.decode(buf, { useTArray: true });
    return { width: img.width, height: img.height, data: img.data };
  }

  function resizeRGBA(src, srcW, srcH, dstW, dstH) {
    if (srcW === dstW && srcH === dstH) return src;
    const dst = Buffer.alloc(dstW * dstH * 4);
    for (let y = 0; y < dstH; y++) {
      const srcYf = Math.min(srcH - 1, Math.max(0, ((y + 0.5) * srcH) / dstH - 0.5));
      const y0 = Math.floor(srcYf);
      const y1 = Math.min(srcH - 1, y0 + 1);
      const wy = srcYf - y0;
      for (let x = 0; x < dstW; x++) {
        const srcXf = Math.min(srcW - 1, Math.max(0, ((x + 0.5) * srcW) / dstW - 0.5));
        const x0 = Math.floor(srcXf);
        const x1 = Math.min(srcW - 1, x0 + 1);
        const wx = srcXf - x0;
        const o = (y * dstW + x) * 4;
        for (let c = 0; c < 4; c++) {
          const p00 = src[(y0 * srcW + x0) * 4 + c];
          const p10 = src[(y0 * srcW + x1) * 4 + c];
          const p01 = src[(y1 * srcW + x0) * 4 + c];
          const p11 = src[(y1 * srcW + x1) * 4 + c];
          const top = p00 + (p10 - p00) * wx;
          const bottom = p01 + (p11 - p01) * wx;
          dst[o + c] = Math.round(top + (bottom - top) * wy);
        }
      }
    }
    return dst;
  }

  const OVERLAY_WIDTH_RATIO = { logo: 0.16, sticker: 0.22 };

  // Alpha-blends `overlay` (resized to a fraction of the base width, keeping its aspect ratio)
  // onto `base` at the given corner and returns a new decoded-RGBA object. Both inputs and the
  // output are the same {width, height, data} shape produced by decodeToRGBA().
  function compositeOverlayOntoBase(base, overlay, position, widthRatio) {
    const targetW = Math.max(1, Math.round(base.width * widthRatio));
    const targetH = Math.max(1, Math.round((overlay.height / overlay.width) * targetW));
    const resized = resizeRGBA(overlay.data, overlay.width, overlay.height, targetW, targetH);
    const margin = Math.round(base.width * 0.04);
    let x, y;
    if (position === 'top-left') { x = margin; y = margin; }
    else if (position === 'top-right') { x = base.width - margin - targetW; y = margin; }
    else if (position === 'bottom-left') { x = margin; y = base.height - margin - targetH; }
    else { x = base.width - margin - targetW; y = base.height - margin - targetH; } // bottom-right (default)
    x = Math.max(0, Math.min(x, base.width - targetW));
    y = Math.max(0, Math.min(y, base.height - targetH));

    const out = Buffer.from(base.data);
    for (let j = 0; j < targetH; j++) {
      const by = y + j;
      if (by < 0 || by >= base.height) continue;
      for (let i = 0; i < targetW; i++) {
        const bx = x + i;
        if (bx < 0 || bx >= base.width) continue;
        const so = (j * targetW + i) * 4;
        const alpha = resized[so + 3] / 255;
        if (alpha <= 0) continue;
        const bo = (by * base.width + bx) * 4;
        out[bo] = Math.round(resized[so] * alpha + out[bo] * (1 - alpha));
        out[bo + 1] = Math.round(resized[so + 1] * alpha + out[bo + 1] * (1 - alpha));
        out[bo + 2] = Math.round(resized[so + 2] * alpha + out[bo + 2] * (1 - alpha));
      }
    }
    return { width: base.width, height: base.height, data: out };
  }

  function encodeRGBAToPng(decoded) {
    const png = new PNG({ width: decoded.width, height: decoded.height });
    Buffer.from(decoded.data).copy(png.data);
    return PNG.sync.write(png);
  }

  // Applies a list of {type, path, position} overlays (from buildImagesAndPrompt's composite
  // mode) onto an already-generated result image. Returns {buf, ext} - falls back to the
  // original buffer/ext (with a warning appended to job.warning) if the base image can't be
  // decoded (e.g. a webp/gif result, which decodeToRGBA doesn't support).
  function applyCompositeOverlays(job, buf, ext) {
    if (!job.compositeOverlays || !job.compositeOverlays.length) return { buf, ext };
    let base;
    try {
      base = decodeToRGBA(buf);
    } catch (e) {
      job.warning = (job.warning ? job.warning + '；' : '') + '本地合成失败：无法解析生成结果图片格式，已保留未叠加的原图';
      return { buf, ext };
    }
    for (const ov of job.compositeOverlays) {
      try {
        const overlay = decodeToRGBA(fs.readFileSync(ov.path));
        base = compositeOverlayOntoBase(base, overlay, ov.position, OVERLAY_WIDTH_RATIO[ov.type] || 0.2);
      } catch (e) {
        const label = ov.type === 'logo' ? 'LOGO' : '贴纸';
        job.warning = (job.warning ? job.warning + '；' : '') + `本地合成${label}失败: ${e.message || e}`;
      }
    }
    return { buf: encodeRGBAToPng(base), ext: 'png' };
  }

  // ---------- job queue ----------

  const jobs = new Map();
  const pendingQueue = [];
  let activeCount = 0;
  const persistedTasks = new Map();
  let taskStoreLoaded = false;

  function getTaskStoreFile() {
    return path.join(workspace.getWorkspaceRoot(), '.genpic', 'tasks.json');
  }

  function taskSnapshot(job) {
    const { images, ...safeJob } = job;
    return {
      ...safeJob,
      imageCount: Array.isArray(images) ? images.length : 0,
      updatedAt: Date.now(),
    };
  }

  function persistJob(job) {
    if (!job || !job.id) return;
    persistedTasks.set(job.id, taskSnapshot(job));
    const storeFile = getTaskStoreFile();
    fs.mkdirSync(path.dirname(storeFile), { recursive: true });
    const tempPath = `${storeFile}.${process.pid}.tmp`;
    fs.writeFileSync(tempPath, JSON.stringify({
      version: 1,
      updatedAt: new Date().toISOString(),
      tasks: Array.from(persistedTasks.values()),
    }, null, 2));
    fs.renameSync(tempPath, storeFile);
  }

  function loadPersistedJobs() {
    if (taskStoreLoaded) return;
    taskStoreLoaded = true;
    const storeFile = getTaskStoreFile();
    let parsed;
    try {
      parsed = JSON.parse(fs.readFileSync(storeFile, 'utf8'));
    } catch {
      return;
    }
    if (!parsed || parsed.version !== 1 || !Array.isArray(parsed.tasks)) return;
    for (const raw of parsed.tasks) {
      if (!raw || typeof raw.id !== 'string' || !raw.root || typeof raw.state !== 'string') continue;
      const job = {
        ...raw,
        images: [],
        compositeOverlays: Array.isArray(raw.compositeOverlays) ? raw.compositeOverlays : [],
      };
      if (!models.MODEL_IDS.has(job.model)) job.model = config.model;
      jobs.set(job.id, job);
      persistedTasks.set(job.id, taskSnapshot(job));
    }

    for (const job of jobs.values()) {
      if (job.state === 'queued') {
        job.state = 'failed';
        job.finishedAt = Date.now();
        job.error = '服务重启前任务仍在排队，请重新提交';
        persistJob(job);
      } else if (job.state === 'running' || job.state === 'submitted') {
        if (!job.taskId) {
          job.state = 'failed';
          job.finishedAt = Date.now();
          job.error = '服务重启时任务尚未获得供应商任务 ID，请重新提交';
          persistJob(job);
        } else {
          runJob(job);
        }
      }
    }
  }

  function createJob(opts) {
    const id = crypto.randomUUID();
    const job = {
      id,
      root: opts.root,
      folderName: opts.folderName,
      kind: opts.kind,
      shopName: opts.shopName,
      dishName: opts.dishName || null,
      model: models.MODEL_IDS.has(opts.model) ? opts.model : config.model,
      prompt: opts.prompt,
      size: opts.size,
      aspectRatio: opts.aspectRatio,
      images: opts.images || [],
      outputDir: opts.outputDir,
      outputBaseName: opts.outputBaseName,
      compositeOverlays: opts.compositeOverlays || [],
      state: 'queued',
      progress: '0%',
      taskId: null,
      cost: null,
      resultUrl: null,
      remoteUrl: null,
      width: null,
      height: null,
      fileSizeBytes: null,
      error: null,
      warning: opts.warning || null,
      createdAt: Date.now(),
      startedAt: null,
      finishedAt: null,
    };
    jobs.set(id, job);
    persistJob(job);
    const jobTitle = job.dishName ? `${job.shopName} / ${job.dishName}` : `${job.shopName} / ${job.kind}`;
    logs.pushSystemLog(`生成任务已提交：${jobTitle}（${job.model}）`);
    if (activeCount < config.maxConcurrentJobs) {
      startJob(job);
    } else {
      pendingQueue.push(id);
    }
    return job;
  }

  function startJob(job) {
    runJob(job);
  }

  function runJob(job) {
    activeCount++;
    job.state = 'running';
    job.startedAt = job.startedAt || Date.now();
    persistJob(job);
    processJob(job)
      .catch((e) => {
        job.state = 'failed';
        job.error = job.error || e.message || String(e);
      })
      .finally(() => {
        const jobTitle = job.dishName ? `${job.shopName} / ${job.dishName}` : `${job.shopName} / ${job.kind}`;
        if (job.state === 'success') logs.pushSystemLog(`生成完成：${jobTitle}`, 'success');
        else if (job.state === 'failed') logs.pushSystemLog(`生成失败：${jobTitle}，${job.error || '未知错误'}`, 'error');
        job.finishedAt = Date.now();
        persistJob(job);
        activeCount--;
        const nextId = pendingQueue.shift();
        if (nextId) {
          const nextJob = jobs.get(nextId);
          if (nextJob) startJob(nextJob);
        }
      });
  }

  // Builds the model-specific `params` object for the /v1/media/generate request. Different
  // image models on this API expose different (and sometimes confusingly named) parameters -
  // e.g. wan2.6-image has no separate aspect_ratio field, its required "size" param IS the
  // aspect-ratio string (auto/1:1/16:9/...), plus an optional prompt_extend flag.
  function buildParamsForModel(modelId, job) {
    const params = {};
    if (modelId === 'gpt-image-2') {
      params.size = 'auto';
      params.quality = 'auto';
      params.resolution = job.size || '1K';
      params.n = 1;
      params.response_format = 'url';
      if (job.aspectRatio && job.aspectRatio !== 'auto') params.aspect_ratio = job.aspectRatio;
    } else if (modelId === 'gpt-image-2-guan') {
      params.size = 'auto';
      params.quality = 'auto';
    } else if (modelId === 'wan2.6-image') {
      params.size = job.aspectRatio || job.size || 'auto';
      params.prompt_extend = true;
    } else {
      if (job.size) params.size = models.NO_1K_SUPPORT.has(modelId) && job.size === '1K' ? '2K' : job.size;
      if (job.aspectRatio) params.aspect_ratio = job.aspectRatio;
    }
    let images = job.images;
    if (modelId === 'wan2.6-image' && images.length > 4) {
      job.warning = (job.warning ? job.warning + '；' : '') + 'wan2.6-image 最多支持4张参考图，已自动截取前4张';
      images = images.slice(0, 4);
    }
    if (images.length === 1) params.images = images[0];
    else if (images.length > 1) params.images = images;
    return params;
  }

  async function processJob(job) {
    const resuming = !!job.taskId;
    if (!resuming) {
      const body = {
        model: job.model,
        prompt: job.prompt,
        params: buildParamsForModel(job.model, job),
      };

      const submit = await apiRequest('POST', '/v1/media/generate', body);
      const taskId = submit.json && (submit.json.task_id || (submit.json.data && submit.json.data.task_id));
      if (submit.statusCode !== 200 || !submit.json || !taskId) {
        throw new Error('提交生成任务失败: ' + (submit.json ? JSON.stringify(submit.json) : submit.raw.slice(0, 500)));
      }
      job.taskId = taskId;
      persistJob(job);
    }

    await sleep(resuming ? 1000 : 7000);
    const start = job.startedAt || Date.now();
    const TIMEOUT_MS = 10 * 60 * 1000;
    for (;;) {
      if (Date.now() - start > TIMEOUT_MS) {
        job.state = 'failed';
        job.error = '轮询超时（10分钟未完成）';
        return;
      }
      const statusPath = (job.model === 'gpt-image-2' || job.model === 'gpt-image-2-guan')
        ? `/v1/media/status?task_id=${encodeURIComponent(job.taskId)}`
        : `/v1/skills/task-status?task_id=${encodeURIComponent(job.taskId)}`;
      const statusResp = await apiRequest('GET', statusPath);
      const status = statusResp.json;
      if (!status) {
        await sleep(5000);
        continue;
      }
      job.progress = String(status.progress ?? job.progress);
      if (status.cost !== undefined) job.cost = status.cost;
      persistJob(job);

      if (status.is_final) {
        if (status.state === 'success' && status.result_url) {
          job.remoteUrl = status.result_url;
          const buf = await downloadBuffer(status.result_url);
          let finalBuf, ext;
          finalBuf = buf;
          ext = guessExtFromUrl(status.result_url);
          ({ buf: finalBuf, ext } = applyCompositeOverlays(job, finalBuf, ext));
          fs.mkdirSync(job.outputDir, { recursive: true });
          const savePath = path.join(job.outputDir, `${job.outputBaseName}.${ext}`);
          fs.writeFileSync(savePath, finalBuf);
          const dims = getImageSize(finalBuf) || {};
          job.width = dims.width || null;
          job.height = dims.height || null;
          job.fileSizeBytes = finalBuf.length;
          job.resultPath = savePath;
          job.resultUrl = '/files?path=' + encodeURIComponent(savePath);
          const creationHistoryDir = path.basename(job.outputDir) === '菜品图'
            ? path.dirname(job.outputDir)
            : job.outputDir;
          appendCreationHistory(creationHistoryDir, {
            id: job.id,
            root: job.root,
            folderName: job.folderName,
            shopName: job.shopName,
            kind: job.kind,
            name: job.dishName || job.kind,
            dishName: job.dishName,
            fileName: path.basename(savePath),
            relativePath: path.relative(creationHistoryDir, savePath),
            remoteUrl: job.remoteUrl,
            model: job.model,
            cost: job.cost,
            width: job.width,
            height: job.height,
            fileSizeBytes: job.fileSizeBytes,
            generatedAt: new Date().toISOString(),
          });
          job.state = 'success';
        } else {
          job.state = 'failed';
          job.error = status.error || status.status || '生成失败';
          job.cost = status.cost ?? job.cost;
        }
        return;
      }
      await sleep(5000);
    }
  }

  // ---------- 创作历史（generation-history.json） ----------

  function loadCreationHistory(outputDir) {
    const historyPath = path.join(outputDir, 'generation-history.json');
    if (!fs.existsSync(historyPath)) return [];
    try {
      const records = JSON.parse(fs.readFileSync(historyPath, 'utf8'));
      return Array.isArray(records) ? records : [];
    } catch {
      return [];
    }
  }

  function appendCreationHistory(outputDir, record) {
    fs.mkdirSync(outputDir, { recursive: true });
    const historyPath = path.join(outputDir, 'generation-history.json');
    const records = loadCreationHistory(outputDir).filter((item) => item.id !== record.id);
    records.push(record);
    const tempPath = historyPath + '.tmp';
    fs.writeFileSync(tempPath, JSON.stringify(records, null, 2));
    fs.renameSync(tempPath, historyPath);
  }

  return {
    createJob,
    getJob: (id) => jobs.get(id),
    listJobs: () => Array.from(jobs.values()),
    loadPersistedJobs,
    buildImagesAndPrompt,
    readAsDataUri,
    loadCreationHistory,
    appendCreationHistory,
  };
}

module.exports = { createGenerationService };