// 服务端数据层: DuckDB (官方 @duckdb/node-api)
// 业务数据全部存储在服务端数据库文件 (DB_PATH, 生产建议挂持久化数据卷),
// 客户端不再持有任何数据库, 仅保留最近数据的读缓存。
import { DuckDBInstance } from '@duckdb/node-api'
import path from 'node:path'
import fs from 'node:fs'

let instance = null
let conn = null

const CATS = ['top', 'bottom', 'outer', 'dress', 'shoes', 'accessory']

function dbFile() {
  const p = process.env.DB_PATH || path.resolve(process.cwd(), 'data', 'wardrobe.duckdb')
  fs.mkdirSync(path.dirname(p), { recursive: true })
  return p
}

// 单连接 + 操作串行化: DuckDB 单写入者, 避免并发操作交叠
let chain = Promise.resolve()
export function enqueue(fn) {
  const p = chain.then(fn)
  chain = p.catch(() => {})
  return p
}

async function rows(sql, params = []) {
  const r = await conn.run(sql, params)
  return (await r.getRowObjects()) ?? []
}

async function one(sql, params = []) {
  const r = await rows(sql, params)
  return r.length ? r[0] : null
}

const nowIso = () => new Date().toISOString()
export const uu = () => globalThis.crypto.randomUUID()

function parseArr(v) {
  if (Array.isArray(v)) return v
  if (typeof v === 'string') {
    try {
      const p = JSON.parse(v)
      return Array.isArray(p) ? p : []
    } catch {
      return []
    }
  }
  return []
}

function mapClothing(x) {
  return { ...x, seasons: parseArr(x.seasons), occasions: parseArr(x.occasions) }
}

function mapOutfit(x) {
  return { ...x, item_ids: parseArr(x.item_ids) }
}

export async function initDb() {
  const file = dbFile()
  instance = await DuckDBInstance.create(file)
  conn = await instance.connect()
  await conn.run(`CREATE TABLE IF NOT EXISTS users (
      id VARCHAR PRIMARY KEY,
      email VARCHAR UNIQUE,
      phone VARCHAR UNIQUE,
      nickname VARCHAR NOT NULL DEFAULT '',
      avatar_path VARCHAR,
      created_at VARCHAR NOT NULL
  )`)
  await conn.run(`CREATE TABLE IF NOT EXISTS sessions (
      token VARCHAR PRIMARY KEY,
      user_id VARCHAR NOT NULL,
      created_at VARCHAR NOT NULL
  )`)
  await conn.run(`CREATE TABLE IF NOT EXISTS clothing_items (
      id VARCHAR PRIMARY KEY,
      user_id VARCHAR NOT NULL,
      name VARCHAR NOT NULL,
      category VARCHAR NOT NULL,
      color VARCHAR NOT NULL,
      brand VARCHAR,
      material VARCHAR,
      seasons VARCHAR DEFAULT '[]',
      occasions VARCHAR DEFAULT '[]',
      formality INTEGER DEFAULT 50,
      thickness INTEGER DEFAULT 50,
      image_path VARCHAR,
      purchase_date VARCHAR,
      purchase_price DOUBLE,
      last_cleaned VARCHAR,
      clean_method VARCHAR,
      wear_count INTEGER DEFAULT 0,
      last_worn VARCHAR,
      is_favorite BOOLEAN DEFAULT FALSE,
      created_at VARCHAR NOT NULL,
      updated_at VARCHAR NOT NULL
  )`)
  await conn.run(`CREATE TABLE IF NOT EXISTS outfits (
      id VARCHAR PRIMARY KEY,
      user_id VARCHAR NOT NULL,
      name VARCHAR NOT NULL,
      item_ids VARCHAR DEFAULT '[]',
      occasion VARCHAR,
      season VARCHAR,
      match_score INTEGER,
      ai_analysis VARCHAR,
      is_saved BOOLEAN DEFAULT FALSE,
      created_at VARCHAR NOT NULL
  )`)
  await conn.run(`CREATE TABLE IF NOT EXISTS daily_records (
      id VARCHAR PRIMARY KEY,
      user_id VARCHAR NOT NULL,
      date VARCHAR NOT NULL,
      outfit_id VARCHAR,
      weather_temp DOUBLE,
      weather_condition VARCHAR,
      notes VARCHAR,
      created_at VARCHAR NOT NULL,
      UNIQUE(user_id, date)
  )`)
  await conn.run(`CREATE INDEX IF NOT EXISTS idx_sessions_user ON sessions(user_id)`)
  await conn.run(`CREATE INDEX IF NOT EXISTS idx_clothing_user ON clothing_items(user_id)`)
  await conn.run(`CREATE INDEX IF NOT EXISTS idx_clothing_category ON clothing_items(category)`)
  await conn.run(`CREATE INDEX IF NOT EXISTS idx_outfits_user ON outfits(user_id)`)
  await conn.run(`CREATE INDEX IF NOT EXISTS idx_daily_user_date ON daily_records(user_id, date)`)
  console.log(`[db] DuckDB ready at ${file}`)
}

// ── users / sessions ──

export function dbCreateUser(id, email, phone, nickname) {
  return enqueue(async () => {
    await conn.run(
      'INSERT INTO users (id, email, phone, nickname, created_at) VALUES (?,?,?,?,?)',
      [id, email, phone, nickname, nowIso()],
    )
    return { id, email, phone, nickname, avatar_path: null, created_at: nowIso() }
  })
}

export const dbGetUserByEmail = (email) => enqueue(() =>
  one('SELECT id, email, phone, nickname, avatar_path, created_at FROM users WHERE email = ?', [email]))

export const dbGetUserByPhone = (phone) => enqueue(() =>
  one('SELECT id, email, phone, nickname, avatar_path, created_at FROM users WHERE phone = ?', [phone]))

export const dbGetUserById = (id) => enqueue(() =>
  one('SELECT id, email, phone, nickname, avatar_path, created_at FROM users WHERE id = ?', [id]))

export const dbCreateSession = (token, userId) => enqueue(async () => {
  await conn.run('INSERT INTO sessions (token, user_id, created_at) VALUES (?,?,?)', [token, userId, nowIso()])
})

export const dbGetSession = (token) => enqueue(() =>
  one('SELECT token, user_id, created_at FROM sessions WHERE token = ?', [token]))

export const dbDeleteSession = (token) => enqueue(async () => {
  await conn.run('DELETE FROM sessions WHERE token = ?', [token])
})

// ── clothing ──

export function dbCreateClothing(userId, data) {
  return enqueue(async () => {
    const t = nowIso()
    const item = {
      id: uu(),
      user_id: userId,
      name: data.name,
      category: data.category,
      color: data.color,
      brand: data.brand ?? null,
      material: data.material ?? null,
      seasons: data.seasons ?? [],
      occasions: data.occasions ?? [],
      formality: data.formality ?? 50,
      thickness: data.thickness ?? 50,
      image_path: data.image_path ?? null,
      purchase_date: data.purchase_date ?? null,
      purchase_price: data.purchase_price ?? null,
      last_cleaned: data.last_cleaned ?? null,
      clean_method: data.clean_method ?? null,
      wear_count: data.wear_count ?? 0,
      last_worn: data.last_worn ?? null,
      is_favorite: data.is_favorite ?? false,
      created_at: t,
      updated_at: t,
    }
    await conn.run(
      `INSERT INTO clothing_items (id, user_id, name, category, color, brand, material, seasons, occasions, formality, thickness, image_path, purchase_date, purchase_price, last_cleaned, clean_method, wear_count, last_worn, is_favorite, created_at, updated_at)
       VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?,?)`,
      [
        item.id, item.user_id, item.name, item.category, item.color,
        item.brand, item.material, JSON.stringify(item.seasons), JSON.stringify(item.occasions),
        item.formality, item.thickness, item.image_path,
        item.purchase_date, item.purchase_price, item.last_cleaned,
        item.clean_method, item.wear_count, item.last_worn,
        item.is_favorite, item.created_at, item.updated_at,
      ],
    )
    return item
  })
}

export const dbListClothing = (userId, category) => enqueue(async () => {
  const base = 'SELECT id, user_id, name, category, color, brand, material, seasons, occasions, formality, thickness, image_path, purchase_date, purchase_price, last_cleaned, clean_method, wear_count, last_worn, is_favorite, created_at, updated_at FROM clothing_items'
  const r = category
    ? await rows(`${base} WHERE user_id = ? AND category = ? ORDER BY created_at DESC`, [userId, category])
    : await rows(`${base} WHERE user_id = ? ORDER BY created_at DESC`, [userId])
  return r.map(mapClothing)
})

export async function getClothing(userId, id) {
  return enqueue(async () => {
    const x = await one('SELECT * FROM clothing_items WHERE id = ? AND user_id = ?', [id, userId])
    return x ? mapClothing(x) : null
  })
}

export const dbUpdateClothing = (userId, id, name, category, color) => enqueue(async () => {
  await conn.run(
    'UPDATE clothing_items SET name = ?, category = ?, color = ?, updated_at = ? WHERE id = ? AND user_id = ?',
    [name, category, color, nowIso(), id, userId],
  )
})

export const dbDeleteClothing = (userId, id) => enqueue(async () => {
  await conn.run('DELETE FROM clothing_items WHERE id = ? AND user_id = ?', [id, userId])
})

// ── outfits ──

export function dbCreateOutfit(userId, data) {
  return enqueue(async () => {
    const outfit = {
      id: uu(),
      user_id: userId,
      name: data.name,
      item_ids: data.item_ids ?? [],
      occasion: data.occasion ?? null,
      season: data.season ?? null,
      match_score: null,
      ai_analysis: null,
      is_saved: false,
      created_at: nowIso(),
    }
    await conn.run(
      'INSERT INTO outfits (id, user_id, name, item_ids, occasion, season, match_score, ai_analysis, is_saved, created_at) VALUES (?,?,?,?,?,?,?,?,?,?)',
      [
        outfit.id, outfit.user_id, outfit.name, JSON.stringify(outfit.item_ids),
        outfit.occasion, outfit.season, outfit.match_score,
        outfit.ai_analysis, outfit.is_saved, outfit.created_at,
      ],
    )
    return outfit
  })
}

export const dbListOutfits = (userId) => enqueue(async () => {
  const r = await rows(
    'SELECT id, user_id, name, item_ids, occasion, season, match_score, ai_analysis, is_saved, created_at FROM outfits WHERE user_id = ? ORDER BY created_at DESC',
    [userId],
  )
  return r.map(mapOutfit)
})

// ── daily records ──

export function dbUpsertDaily(userId, data) {
  return enqueue(async () => {
    const record = {
      id: uu(),
      user_id: userId,
      date: data.date,
      outfit_id: data.outfit_id ?? null,
      weather_temp: data.weather_temp ?? null,
      weather_condition: data.weather_condition ?? null,
      notes: data.notes ?? null,
      created_at: nowIso(),
    }
    await conn.run(
      `INSERT INTO daily_records (id, user_id, date, outfit_id, weather_temp, weather_condition, notes, created_at)
       VALUES (?,?,?,?,?,?,?,?)
       ON CONFLICT (user_id, date) DO UPDATE SET outfit_id = excluded.outfit_id, weather_temp = excluded.weather_temp, weather_condition = excluded.weather_condition, notes = excluded.notes`,
      [
        record.id, record.user_id, record.date, record.outfit_id,
        record.weather_temp, record.weather_condition, record.notes, record.created_at,
      ],
    )
    return record
  })
}

export const dbListDaily = (userId, limit) => enqueue(async () => {
  const r = await rows(
    'SELECT id, user_id, date, outfit_id, weather_temp, weather_condition, notes, created_at FROM daily_records WHERE user_id = ? ORDER BY date DESC LIMIT ?',
    [userId, limit],
  )
  return r
})

// ── stats ──

export function dbGetStats(userId) {
  return enqueue(async () => {
    const [totalItems, totalOutfits, favoriteCount] = await Promise.all([
      count('SELECT COUNT(*) AS c FROM clothing_items WHERE user_id = ?', [userId]),
      count('SELECT COUNT(*) AS c FROM outfits WHERE user_id = ?', [userId]),
      count('SELECT COUNT(*) AS c FROM clothing_items WHERE user_id = ? AND is_favorite = TRUE', [userId]),
    ])
    const cutoff = new Date(Date.now() - 30 * 864e5).toISOString().slice(0, 10)
    const unworn30d = await count(
      'SELECT COUNT(*) AS c FROM clothing_items WHERE user_id = ? AND (last_worn IS NULL OR last_worn < ?)',
      [userId, cutoff],
    )
    const needsCleaning = await count(
      'SELECT COUNT(*) AS c FROM clothing_items WHERE user_id = ? AND (last_cleaned IS NULL OR last_cleaned < ?)',
      [userId, cutoff],
    )
    const utilizationRate = totalItems > 0 ? Math.round(((totalItems - unworn30d) / totalItems) * 100) : 0

    const catRows = await rows(
      'SELECT category, COUNT(*) AS c FROM clothing_items WHERE user_id = ? GROUP BY category',
      [userId],
    )
    const categoryCounts = {}
    for (const c of CATS) categoryCounts[c] = 0
    for (const r of catRows) categoryCounts[r.category] = Number(r.c)

    return {
      total_items: totalItems,
      total_outfits: totalOutfits,
      utilization_rate: utilizationRate,
      category_counts: categoryCounts,
      favorite_count: favoriteCount,
      unworn_30d: unworn30d,
      needs_cleaning: needsCleaning,
    }
  })
}

async function count(sql, params) {
  const r = await rows(sql, params)
  return r.length ? Number(r[0].c) : 0
}

// ── MCP 工具 (由服务端直接操作数据库, user_id 取鉴权用户) ──

export function mcpTools() {
  return [
    { name: 'list_clothing', description: '获取用户衣橱中的所有衣物列表', input_schema: '{"type":"object","properties":{"category":{"type":"string"}},"required":[]}' },
    { name: 'get_clothing', description: '根据ID获取单件衣物详情', input_schema: '{"type":"object","properties":{"id":{"type":"string"}},"required":["id"]}' },
    { name: 'add_clothing', description: '添加新衣物到衣橱', input_schema: '{"type":"object","properties":{"name":{"type":"string"},"category":{"type":"string"},"color":{"type":"string"},"brand":{"type":"string"},"seasons":{"type":"array","items":{"type":"string"}},"occasions":{"type":"array","items":{"type":"string"}}},"required":["name","category","color"]}' },
    { name: 'update_clothing', description: '更新衣物信息', input_schema: '{"type":"object","properties":{"id":{"type":"string"},"name":{"type":"string"},"category":{"type":"string"},"color":{"type":"string"}},"required":["id"]}' },
    { name: 'delete_clothing', description: '从衣橱中删除衣物', input_schema: '{"type":"object","properties":{"id":{"type":"string"}},"required":["id"]}' },
    { name: 'list_outfits', description: '获取用户的所有搭配方案', input_schema: '{"type":"object","properties":{},"required":[]}' },
    { name: 'add_outfit', description: '创建新的搭配方案', input_schema: '{"type":"object","properties":{"name":{"type":"string"},"item_ids":{"type":"array","items":{"type":"string"}},"occasion":{"type":"string"},"season":{"type":"string"}},"required":["name","item_ids"]}' },
    { name: 'get_wardrobe_stats', description: '获取衣橱统计数据(总数、利用率、分类统计等)', input_schema: '{"type":"object","properties":{},"required":[]}' },
    { name: 'record_daily_outfit', description: '记录每日穿搭', input_schema: '{"type":"object","properties":{"date":{"type":"string"},"outfit_id":{"type":"string"},"notes":{"type":"string"}},"required":["date"]}' },
    { name: 'list_daily_records', description: '获取穿搭日历记录', input_schema: '{"type":"object","properties":{"limit":{"type":"integer"}},"required":[]}' },
  ]
}

// 返回 {ok, value} 或 throw {status,message}
export async function mcpCall(toolName, args = {}, userId) {
  const a = { ...args, user_id: userId }
  switch (toolName) {
    case 'list_clothing':
      return { ok: true, value: await dbListClothing(userId, a.category || null) }
    case 'get_clothing': {
      const item = await getClothing(userId, a.id)
      return { ok: true, value: item ?? { error: '衣物不存在' } }
    }
    case 'add_clothing': {
      if (!a.name || !a.category || !a.color) throw { status: 400, message: '缺少必填字段' }
      return { ok: true, value: await dbCreateClothing(userId, a) }
    }
    case 'update_clothing':
      await dbUpdateClothing(userId, a.id, a.name || '', a.category || '', a.color || '')
      return { ok: true, value: { success: true } }
    case 'delete_clothing':
      await dbDeleteClothing(userId, a.id)
      return { ok: true, value: { success: true } }
    case 'list_outfits':
      return { ok: true, value: await dbListOutfits(userId) }
    case 'add_outfit': {
      if (!a.name || !Array.isArray(a.item_ids)) throw { status: 400, message: '缺少必填字段' }
      return { ok: true, value: await dbCreateOutfit(userId, a) }
    }
    case 'get_wardrobe_stats':
      return { ok: true, value: await dbGetStats(userId) }
    case 'record_daily_outfit':
      if (!a.date) throw { status: 400, message: '缺少 date' }
      return { ok: true, value: await dbUpsertDaily(userId, a) }
    case 'list_daily_records':
      return { ok: true, value: await dbListDaily(userId, a.limit || 30) }
    default:
      throw { status: 400, message: `Unknown tool: ${toolName}` }
  }
}