/**
 * fun 结点：img-scale — 图片等比缩放（宽高同乘同一比例）
 *
 * 入参（inVars 顺序，与 img-cropping 一致：先路径再参数）：
 * - imagePath：源图（相对流程目录或绝对路径）
 * - savePath：输出路径
 * - scale：缩放系数。支持：
 *   - 0.8 → 长宽各 ×0.8
 *   - "80%" → 80%；整数 10～100 视为百分比，如 80 即 80%
 *   - 1～10 之间的小数/整数为倍率，如 2 即 2 倍、1.5 即 1.5 倍（整数 10 为 10% 而非 10 倍）
 */

const path = require('path')
const fs = require('fs')
const { spawnSync } = require('child_process')
const { getPythonExeFromConfig } = require('../../../../python-exe-from-config.js')

const tagName = 'img-scale'

const configPath = process.env.STATIC_ROOT
  ? path.join(path.dirname(path.resolve(process.env.STATIC_ROOT)), 'config.js')
  : path.join(__dirname, '..', '..', '..', '..', '..', 'config.js')
const config = fs.existsSync(configPath) ? require(configPath) : {}
const projectRoot = (config.projectRoot && fs.existsSync(config.projectRoot))
  ? config.projectRoot
  : path.dirname(path.resolve(configPath))
const scaleScriptPath = path.join(projectRoot, 'python', 'scripts', 'img-scale-proportional.py')

function buildAbsolutePath (p, folderPath) {
  if (p == null || p === '') return null
  const s = typeof p === 'string' ? p.trim() : String(p)
  if (!s) return null
  if (path.isAbsolute(s) || /^[A-Za-z]:/.test(s)) return path.normalize(s)
  return folderPath ? path.join(folderPath, s) : path.resolve(projectRoot, s)
}

/**
 * @param {{ imagePath: string, savePath: string, scale: string|number, folderPath?: string }} input
 */
async function executeImgScale ({ imagePath, savePath, scale, folderPath }) {
  if (imagePath == null || String(imagePath).trim() === '') {
    return { success: false, error: 'img-scale 缺少 imagePath（inVars[0]）' }
  }
  if (savePath == null || String(savePath).trim() === '') {
    return { success: false, error: 'img-scale 缺少 savePath（inVars[1]）' }
  }
  if (scale === undefined || scale === null || scale === '') {
    return { success: false, error: 'img-scale 缺少 scale（inVars[2]，如 0.8 或 80%）' }
  }

  const scaleStr = typeof scale === 'number' && Number.isFinite(scale) ? String(scale) : String(scale).trim()
  if (!scaleStr) return { success: false, error: 'img-scale scale 无效' }

  const absIn = buildAbsolutePath(String(imagePath).trim(), folderPath)
  const absOut = buildAbsolutePath(String(savePath).trim(), folderPath)
  if (!absIn || !absOut) return { success: false, error: 'img-scale 路径无效' }
  if (!fs.existsSync(absIn)) return { success: false, error: `img-scale 源文件不存在: ${absIn}` }
  if (!fs.existsSync(scaleScriptPath)) {
    return { success: false, error: `脚本不存在: ${scaleScriptPath}` }
  }

  const pythonExe = getPythonExeFromConfig(config)
  const r = spawnSync(pythonExe, [scaleScriptPath, absIn, absOut, scaleStr], {
    encoding: 'utf-8',
    timeout: 120_000,
    cwd: projectRoot,
  })

  const combined = ((r.stdout || '') + '\n' + (r.stderr || '')).trim()
  if (r.status !== 0) {
    return { success: false, error: combined || 'img-scale 执行失败' }
  }

  let meta = {}
  const lines = (r.stdout || '').split(/\r?\n/).map((l) => l.trim()).filter(Boolean)
  const jsonLine = lines.filter((l) => l.startsWith('{')).pop()
  if (jsonLine) {
    try {
      meta = JSON.parse(jsonLine)
    } catch (_) {}
  }
  if (!meta.success) {
    return { success: false, error: meta.error || combined || 'img-scale 未返回成功' }
  }

  return {
    success: true,
    path: absOut,
    value: absOut,
    result: absOut,
    scaled: {
      scale: meta.scale,
      sourceWidth: meta.sourceWidth,
      sourceHeight: meta.sourceHeight,
      width: meta.width,
      height: meta.height,
    },
  }
}

module.exports = { tagName, executeImgScale }