import { Capacitor } from '@capacitor/core'
import { CapacitorSQLite, SQLiteConnection } from '@capacitor-community/sqlite'
import { defineCustomElements as defineJeep } from 'jeep-sqlite/loader'

const DB_NAME = 'echo_local'
const DB_VERSION = 1
const TRANSACTION_TABLE_SQL = `
  CREATE TABLE IF NOT EXISTS transactions (
    id TEXT PRIMARY KEY NOT NULL,
    amount REAL NOT NULL,
    merchant TEXT NOT NULL,
    category TEXT DEFAULT 'Uncategorized',
    date TEXT NOT NULL,
    note TEXT,
    sync_status INTEGER DEFAULT 0,
    entry_type TEXT DEFAULT 'expense',
    fund_source_type TEXT DEFAULT 'cash',
    fund_source_name TEXT,
    fund_target_type TEXT DEFAULT 'merchant',
    fund_target_name TEXT,
    impact_expense INTEGER DEFAULT 1,
    impact_income INTEGER DEFAULT 0,
    ai_category TEXT,
    ai_tags TEXT,
    ai_confidence REAL,
    ai_reason TEXT,
    ai_status TEXT DEFAULT 'idle',
    ai_model TEXT,
    ai_normalized_merchant TEXT
  );
`
const MERCHANT_PROFILE_TABLE_SQL = `
  CREATE TABLE IF NOT EXISTS merchant_profiles (
    merchant_key TEXT PRIMARY KEY NOT NULL,
    normalized_merchant TEXT NOT NULL,
    category TEXT,
    tags TEXT,
    hit_count INTEGER DEFAULT 0,
    updated_at TEXT NOT NULL
  );
`
const TRANSACTION_REQUIRED_COLUMNS = {
  entry_type: "TEXT DEFAULT 'expense'",
  fund_source_type: "TEXT DEFAULT 'cash'",
  fund_source_name: 'TEXT',
  fund_target_type: "TEXT DEFAULT 'merchant'",
  fund_target_name: 'TEXT',
  impact_expense: 'INTEGER DEFAULT 1',
  impact_income: 'INTEGER DEFAULT 0',
  ai_category: 'TEXT',
  ai_tags: 'TEXT',
  ai_confidence: 'REAL',
  ai_reason: 'TEXT',
  ai_status: "TEXT DEFAULT 'idle'",
  ai_model: 'TEXT',
  ai_normalized_merchant: 'TEXT',
}

let sqliteConnection
let db
let initialized = false
let jeepLoaderPromise
let jeepElementReadyPromise

const waitFor = (ms = 100) =>
  new Promise((resolve) => {
    setTimeout(resolve, ms)
  })

const ensureStoreReady = async (jeepEl, retries = 5) => {
  for (let attempt = 0; attempt < retries; attempt += 1) {
    const isOpen = (await jeepEl.isStoreOpen?.()) === true
    if (isOpen) return
    if (typeof jeepEl.openStore === 'function') {
      const opened = await jeepEl.openStore('jeepSqliteStore', 'databases')
      if (opened) return
    }
    await waitFor(200 * (attempt + 1))
  }
  throw new Error('jeep-sqlite IndexedDB store failed to initialize')
}

const ensureJeepElement = async () => {
  if (!jeepLoaderPromise) {
    jeepLoaderPromise = defineJeep(window)
  }
  await jeepLoaderPromise

  if (!jeepElementReadyPromise) {
    jeepElementReadyPromise = (async () => {
      let jeepEl = document.querySelector('jeep-sqlite')
      if (!jeepEl) {
        jeepEl = document.createElement('jeep-sqlite')
        jeepEl.setAttribute('auto-save', 'true')
        document.body.appendChild(jeepEl)
      }
      jeepEl.setAttribute('wasm-path', '/assets')
      await customElements.whenDefined('jeep-sqlite')
      await jeepEl.componentOnReady?.()
      return jeepEl
    })()
  }

  const element = await jeepElementReadyPromise
  await ensureStoreReady(element)
  await CapacitorSQLite.initWebStore()
}

const ensureTableColumns = async (tableName, requiredColumns) => {
  const result = await db.query(`PRAGMA table_info(${tableName});`)
  const existingColumns = new Set((result?.values || []).map((row) => row.name))

  for (const [columnName, definition] of Object.entries(requiredColumns)) {
    if (!existingColumns.has(columnName)) {
      await db.execute(`ALTER TABLE ${tableName} ADD COLUMN ${columnName} ${definition};`)
    }
  }
}

const prepareConnection = async () => {
  if (!sqliteConnection) {
    sqliteConnection = new SQLiteConnection(CapacitorSQLite)
  }

  if (Capacitor.getPlatform() === 'web') {
    await ensureJeepElement()
  }

  const consistency = await sqliteConnection.checkConnectionsConsistency()
  if (!consistency.result) {
    await sqliteConnection.closeAllConnections()
  }

  const isConn = (await sqliteConnection.isConnection(DB_NAME, false)).result
  if (isConn) {
    db = await sqliteConnection.retrieveConnection(DB_NAME, false)
  } else {
    db = await sqliteConnection.createConnection(DB_NAME, false, 'no-encryption', DB_VERSION, false)
  }

  await db.open()
  await db.execute(TRANSACTION_TABLE_SQL)
  await db.execute(MERCHANT_PROFILE_TABLE_SQL)
  await ensureTableColumns('transactions', TRANSACTION_REQUIRED_COLUMNS)
  initialized = true
}

export const initSQLite = async () => {
  if (!initialized) {
    await prepareConnection()
  }
  return db
}

export const getDb = async () => {
  if (!initialized) {
    await initSQLite()
  }
  return db
}

export const saveDbToStore = async () => {
  await initSQLite()
  if (!sqliteConnection?.saveToStore) return
  try {
    await sqliteConnection.saveToStore(DB_NAME)
  } catch (error) {
    console.warn('[sqlite] saveToStore failed, data remains in memory until next sync', error)
  }
}

export const closeSQLite = async () => {
  if (db) {
    await db.close()
    db = null
  }
  initialized = false
}

export const databaseName = DB_NAME