/**
 * Projects store | 项目状态管理
 * Manages projects with localStorage persistence
 */
import { ref, computed, watch } from 'vue'

// Storage key | 存储键
const STORAGE_KEY = 'ai-canvas-projects'

// Generate unique ID | 生成唯一ID
const generateId = () => `project_${Date.now()}_${Math.random().toString(36).substr(2, 9)}`

// Projects list | 项目列表
export const projects = ref([])

// Current project ID | 当前项目ID
export const currentProjectId = ref(null)

export const projectSyncStatus = ref('idle')
export const projectSyncError = ref('')

const API_BASE = import.meta.env.VITE_SKG_API_BASE || '/api'
const apiUrl = (path) => `${API_BASE}${path.startsWith('/') ? '' : '/'}${path}`
const remoteSaveTimers = new Map()
const remoteSaveSignatures = new Map()
let initPromise = null
let remoteAvailable = false

// Current project | 当前项目
export const currentProject = computed(() => {
  return projects.value.find(p => p.id === currentProjectId.value) || null
})

const dateToSeconds = (value) => {
  if (value instanceof Date) return value.getTime() / 1000
  const parsed = new Date(value)
  return Number.isFinite(parsed.getTime()) ? parsed.getTime() / 1000 : Date.now() / 1000
}

const secondsToDate = (value) => {
  if (value instanceof Date) return value
  const num = Number(value || 0)
  return new Date(num > 100000000000 ? num : num * 1000)
}

const projectFromApi = (item) => ({
  id: item.id,
  name: item.name || '未命名项目',
  thumbnail: item.thumbnail || '',
  visibility: item.visibility || 'private',
  ownerId: item.owner_id || '',
  ownerName: item.owner_name || '',
  ownerEmail: item.owner_email || '',
  ownerProvider: item.owner_provider || '',
  version: item.version || 1,
  createdAt: secondsToDate(item.created_at),
  updatedAt: secondsToDate(item.updated_at),
  canvasData: item.canvas_data || {
    nodes: [],
    edges: [],
    viewport: { x: 100, y: 50, zoom: 0.8 }
  }
})

const projectToApi = (project) => ({
  id: project.id,
  name: project.name || '未命名项目',
  thumbnail: project.thumbnail || '',
  visibility: project.visibility || 'private',
  canvas_data: cleanProjectForStorage(project).canvasData || {
    nodes: [],
    edges: [],
    viewport: { x: 100, y: 50, zoom: 0.8 }
  },
  created_at: dateToSeconds(project.createdAt),
  updated_at: dateToSeconds(project.updatedAt),
  source: 'canvas'
})

const remoteProjectSignature = (project) => {
  const payload = projectToApi(project)
  delete payload.updated_at
  return JSON.stringify(payload)
}

const requestJson = async (path, init = {}) => {
  const response = await fetch(apiUrl(path), {
    ...init,
    headers: {
      ...(init.body instanceof FormData ? {} : { 'Content-Type': 'application/json' }),
      ...(init.headers || {})
    }
  })
  if (!response.ok) {
    const text = await response.text().catch(() => '')
    throw new Error(text || `${path} ${response.status}`)
  }
  return response.json()
}

const mergeProjectLists = (localItems, remoteItems) => {
  const byId = new Map()
  for (const item of remoteItems) byId.set(item.id, item)
  for (const item of localItems) {
    const existing = byId.get(item.id)
    if (!existing || dateToSeconds(item.updatedAt) > dateToSeconds(existing.updatedAt)) {
      byId.set(item.id, item)
    }
  }
  return [...byId.values()].sort((a, b) => dateToSeconds(b.updatedAt) - dateToSeconds(a.updatedAt))
}

/**
 * Load projects from localStorage | 从 localStorage 加载项目
 */
export const loadProjects = () => {
  try {
    const stored = localStorage.getItem(STORAGE_KEY)
    if (stored) {
      const parsed = JSON.parse(stored)
      // Convert date strings back to Date objects | 将日期字符串转换回 Date 对象
      projects.value = parsed.map(p => ({
        ...p,
        createdAt: new Date(p.createdAt),
        updatedAt: new Date(p.updatedAt)
      }))
    }
  } catch (err) {
    console.error('Failed to load projects:', err)
    projects.value = []
  }
}

const saveRemoteProjectNow = async (project) => {
  if (!project?.id) return null
  const signature = remoteProjectSignature(project)
  if (remoteSaveSignatures.get(project.id) === signature) return null
  const response = await requestJson(`/canvas-projects/${encodeURIComponent(project.id)}`, {
    method: 'PUT',
    body: JSON.stringify(projectToApi(project))
  })
  remoteSaveSignatures.set(project.id, signature)
  return response.item ? projectFromApi(response.item) : null
}

const scheduleRemoteSave = (project, delay = 2000) => {
  if (!remoteAvailable || !project?.id) return
  if (remoteSaveTimers.has(project.id)) {
    clearTimeout(remoteSaveTimers.get(project.id))
  }
  remoteSaveTimers.set(project.id, setTimeout(async () => {
    remoteSaveTimers.delete(project.id)
    try {
      projectSyncStatus.value = 'syncing'
      await saveRemoteProjectNow(project)
      projectSyncStatus.value = 'synced'
      projectSyncError.value = ''
    } catch (err) {
      projectSyncStatus.value = 'error'
      projectSyncError.value = err.message || '项目同步失败'
      console.warn('Failed to sync project:', err)
    }
  }, delay))
}

const importLocalProjectsToServer = async (localItems) => {
  if (!localItems.length) return []
  const payload = { projects: localItems.map(projectToApi) }
  const response = await requestJson('/canvas-projects/import', {
    method: 'POST',
    body: JSON.stringify(payload)
  })
  return (response.items || []).map(projectFromApi)
}

export const loadRemoteProjects = async () => {
  try {
    projectSyncStatus.value = 'syncing'
    const localItems = [...projects.value]
    const response = await requestJson('/canvas-projects')
    remoteAvailable = true
    const remoteItems = (response.items || []).map(projectFromApi)
    const importedItems = await importLocalProjectsToServer(localItems)
    const merged = mergeProjectLists(localItems, [...remoteItems, ...importedItems])
    projects.value = merged
    saveProjects({ remote: false })
    projectSyncStatus.value = 'synced'
    projectSyncError.value = ''
    return merged
  } catch (err) {
    remoteAvailable = false
    projectSyncStatus.value = 'error'
    projectSyncError.value = err.message || '项目同步失败'
    console.warn('Remote project sync unavailable:', err)
    return projects.value
  }
}

/**
 * Clean node data for storage | 清理节点数据用于存储
 * Removes base64 data URLs to reduce storage size | 移除 base64 数据减小存储大小
 */
const cleanNodeForStorage = (node) => {
  if (!node.data) return node
  
  const cleanedData = { ...node.data }
  
  // Remove base64 data | 移除 base64 数据
  if (cleanedData.base64) {
    delete cleanedData.base64
  }
  
  // If url is a base64 data URL, keep it only if it's from external source | 如果 url 是 base64，只有外部来源才保留
  if (cleanedData.url?.startsWith?.('data:')) {
    // For uploaded images, we can't persist them in localStorage | 上传的图片无法持久化到 localStorage
    delete cleanedData.url
  }

  // blob: object URLs are session-only and break on reload — never persist them | blob: 仅会话内有效，重载即失效，不持久化
  if (cleanedData.url?.startsWith?.('blob:')) {
    delete cleanedData.url
  }

  // Remove mask data | 移除蒙版数据
  if (cleanedData.maskData) {
    delete cleanedData.maskData
  }
  
  return { ...node, data: cleanedData }
}

/**
 * Clean project for storage | 清理项目用于存储
 */
const cleanProjectForStorage = (project) => {
  return {
    ...project,
    canvasData: project.canvasData ? {
      ...project.canvasData,
      nodes: project.canvasData.nodes?.map(cleanNodeForStorage) || []
    } : project.canvasData,
    // Remove base64 thumbnails | 移除 base64 缩略图
    thumbnail: project.thumbnail?.startsWith?.('data:') ? '' : project.thumbnail
  }
}

/**
 * Save projects to localStorage | 保存项目到 localStorage
 * Handles QuotaExceededError by compressing data | 通过压缩数据处理配额超限错误
 */
export const saveProjects = ({ remote = false } = {}) => {
  // Always clean data before saving | 保存前始终清理数据
  const cleanedProjects = projects.value.map(cleanProjectForStorage)
  
  try {
    localStorage.setItem(STORAGE_KEY, JSON.stringify(cleanedProjects))
  } catch (err) {
    if (err.name === 'QuotaExceededError') {
      console.warn('localStorage quota exceeded, attempting aggressive cleanup...')
      
      // Remove thumbnails and limit old projects | 移除缩略图并限制旧项目
      const minimalProjects = cleanedProjects.map((project, index) => ({
        ...project,
        thumbnail: '', // Remove all thumbnails | 移除所有缩略图
        // Keep only essential canvas data for older projects | 旧项目只保留基本画布数据
        canvasData: index > 10 ? { nodes: [], edges: [], viewport: project.canvasData?.viewport } : project.canvasData
      }))
      
      try {
        localStorage.setItem(STORAGE_KEY, JSON.stringify(minimalProjects))
        console.log('Saved with aggressive cleanup')
        window.$message?.warning('存储空间不足，已自动清理部分数据')
      } catch (retryErr) {
        console.error('Still failed after aggressive cleanup:', retryErr)
        // Last resort: only keep first 5 projects | 最后手段：只保留前5个项目
        try {
          const essentialProjects = minimalProjects.slice(0, 5)
          localStorage.setItem(STORAGE_KEY, JSON.stringify(essentialProjects))
          projects.value = projects.value.slice(0, 5)
          window.$message?.warning('存储空间严重不足，已保留最近 5 个项目')
        } catch (finalErr) {
          console.error('Cannot save even minimal data:', finalErr)
          window.$message?.error('存储失败，请清理浏览器存储空间')
        }
      }
    } else {
      console.error('Failed to save projects:', err)
    }
  }

  if (remote) {
    for (const project of projects.value) scheduleRemoteSave(project)
  }
}

/**
 * Create a new project | 创建新项目
 * @param {string} name - Project name | 项目名称
 * @returns {string} - New project ID | 新项目ID
 */
export const createProject = (name = '未命名项目') => {
  const id = generateId()
  const now = new Date()
  
  const newProject = {
    id,
    name,
    thumbnail: '',
    createdAt: now,
    updatedAt: now,
    // Canvas data | 画布数据
    canvasData: {
      nodes: [],
      edges: [],
      viewport: { x: 100, y: 50, zoom: 0.8 }
    }
  }
  
  projects.value = [newProject, ...projects.value]
  saveProjects()
  scheduleRemoteSave(newProject, 0)
  
  return id
}

/**
 * Update project | 更新项目
 * @param {string} id - Project ID | 项目ID
 * @param {object} data - Update data | 更新数据
 */
export const updateProject = (id, data) => {
  const index = projects.value.findIndex(p => p.id === id)
  if (index === -1) return false
  
  projects.value[index] = {
    ...projects.value[index],
    ...data,
    updatedAt: new Date()
  }
  
  // Move to top of list | 移动到列表顶部
  const [updated] = projects.value.splice(index, 1)
  projects.value = [updated, ...projects.value]
  
  saveProjects()
  scheduleRemoteSave(updated)
  return true
}

/**
 * Update project canvas data | 更新项目画布数据
 * @param {string} id - Project ID | 项目ID
 * @param {object} canvasData - Canvas data (nodes, edges, viewport) | 画布数据
 */
export const updateProjectCanvas = (id, canvasData) => {
  const project = projects.value.find(p => p.id === id)
  if (!project) return false
  
  project.canvasData = {
    ...project.canvasData,
    ...canvasData
  }
  project.updatedAt = new Date()
  
  // Auto-update thumbnail from last edited image/video node | 自动从最后编辑的图片/视频节点更新缩略图
  if (canvasData.nodes) {
    const mediaNodes = canvasData.nodes
      .filter(node => (node.type === 'image' || node.type === 'video') && node.data?.url)
      .sort((a, b) => {
        // Sort by last updated time | 按最后更新时间排序
        const aTime = a.data?.updatedAt || a.data?.createdAt || 0
        const bTime = b.data?.updatedAt || b.data?.createdAt || 0
        return bTime - aTime
      })
    if (mediaNodes.length > 0) {
      const latestNode = mediaNodes[0]
      // Use thumbnail for video nodes, url for image nodes | 视频节点使用缩略图，图片节点使用 URL
      if (latestNode.type === 'video') {
        project.thumbnail = latestNode.data.thumbnail || latestNode.data.url
      } else {
        project.thumbnail = latestNode.data.url
      }
    }
  }
  
  saveProjects()
  scheduleRemoteSave(project)
  return true
}

/**
 * Get project canvas data | 获取项目画布数据
 * @param {string} id - Project ID | 项目ID
 * @returns {object|null} - Canvas data or null | 画布数据或空
 */
export const getProjectCanvas = (id) => {
  const project = projects.value.find(p => p.id === id)
  return project?.canvasData || null
}

/**
 * Delete project | 删除项目
 * @param {string} id - Project ID | 项目ID
 */
export const deleteProject = (id) => {
  projects.value = projects.value.filter(p => p.id !== id)
  saveProjects()
  if (remoteAvailable) {
    requestJson(`/canvas-projects/${encodeURIComponent(id)}`, { method: 'DELETE' })
      .catch(err => console.warn('Failed to delete remote project:', err))
  }
}

/**
 * Duplicate project | 复制项目
 * @param {string} id - Source project ID | 源项目ID
 * @returns {string|null} - New project ID or null | 新项目ID或空
 */
export const duplicateProject = (id) => {
  const source = projects.value.find(p => p.id === id)
  if (!source) return null
  
  const newId = generateId()
  const now = new Date()
  
  const newProject = {
    ...JSON.parse(JSON.stringify(source)), // Deep clone | 深拷贝
    id: newId,
    name: `${source.name} (副本)`,
    createdAt: now,
    updatedAt: now
  }
  
  projects.value = [newProject, ...projects.value]
  saveProjects()
  scheduleRemoteSave(newProject, 0)
  
  return newId
}

/**
 * Rename project | 重命名项目
 * @param {string} id - Project ID | 项目ID
 * @param {string} name - New name | 新名称
 */
export const renameProject = (id, name) => {
  return updateProject(id, { name })
}

/**
 * Update project thumbnail | 更新项目缩略图
 * @param {string} id - Project ID | 项目ID
 * @param {string} thumbnail - Thumbnail URL (base64 or URL) | 缩略图URL
 */
export const updateProjectThumbnail = (id, thumbnail) => {
  return updateProject(id, { thumbnail })
}

/**
 * Get sorted projects | 获取排序后的项目列表
 * @param {string} sortBy - Sort field (updatedAt, createdAt, name) | 排序字段
 * @param {string} order - Sort order (asc, desc) | 排序顺序
 */
export const getSortedProjects = (sortBy = 'updatedAt', order = 'desc') => {
  return computed(() => {
    const sorted = [...projects.value]
    sorted.sort((a, b) => {
      let valueA = a[sortBy]
      let valueB = b[sortBy]
      
      if (valueA instanceof Date) {
        valueA = valueA.getTime()
        valueB = valueB.getTime()
      }
      
      if (typeof valueA === 'string') {
        valueA = valueA.toLowerCase()
        valueB = valueB.toLowerCase()
      }
      
      if (order === 'asc') {
        return valueA > valueB ? 1 : -1
      } else {
        return valueA < valueB ? 1 : -1
      }
    })
    return sorted
  })
}

/**
 * Initialize projects store | 初始化项目存储
 */
export const initProjectsStore = async () => {
  if (initPromise) return initPromise
  initPromise = (async () => {
  loadProjects()
  await loadRemoteProjects()
  return projects.value
  })()
  return initPromise
}

// Export for debugging | 导出用于调试
if (typeof window !== 'undefined') {
  window.__aiCanvasProjects = {
    projects,
    loadProjects,
    saveProjects,
    createProject,
    deleteProject
  }
}