const CouchDB = require("../../../db")
const linkRows = require("../../../db/linkedRows")
const csvParser = require("../../../utilities/csvParser")
const {
  getRowParams,
  getTableParams,
  generateTableID,
} = require("../../../db/utils")
const { FieldTypes } = require("../../../constants")
const { TableSaveFunctions } = require("./utils")

exports.fetch = async function(ctx) {
  const db = new CouchDB(ctx.user.appId)
  const body = await db.allDocs(
    getTableParams(null, {
      include_docs: true,
    })
  )
  ctx.body = body.rows.map(row => row.doc)
}

exports.find = async function(ctx) {
  const db = new CouchDB(ctx.user.appId)
  ctx.body = await db.get(ctx.params.id)
}

exports.save = async function(ctx) {
  const appId = ctx.user.appId
  const db = new CouchDB(appId)
  const { dataImport, ...rest } = ctx.request.body
  let tableToSave = {
    type: "table",
    _id: generateTableID(),
    views: {},
    ...rest,
  }

  // if the table obj had an _id then it will have been retrieved
  let oldTable
  if (ctx.request.body && ctx.request.body._id) {
    oldTable = await db.get(ctx.request.body._id)
  }

  // saving a table is a complex operation, involving many different steps, this
  // has been broken out into a utility to make it more obvious/easier to manipulate
  const tableSaveFunctions = new TableSaveFunctions({
    db,
    ctx,
    oldTable,
    dataImport,
  })
  tableToSave = await tableSaveFunctions.before(tableToSave)

  // make sure that types don't change of a column, have to remove
  // the column if you want to change the type
  if (oldTable && oldTable.schema) {
    for (let propKey of Object.keys(tableToSave.schema)) {
      let column = tableToSave.schema[propKey]
      let oldColumn = oldTable.schema[propKey]
      if (oldColumn && oldColumn.type !== column.type) {
        ctx.throw(400, "Cannot change the type of a column")
      }
    }
  }

  // Don't rename if the name is the same
  let { _rename } = tableToSave
  /* istanbul ignore next */
  if (_rename && _rename.old === _rename.updated) {
    _rename = null
    delete tableToSave._rename
  }

  // rename row fields when table column is renamed
  /* istanbul ignore next */
  if (_rename && tableToSave.schema[_rename.updated].type === FieldTypes.LINK) {
    ctx.throw(400, "Cannot rename a linked column.")
  } else if (_rename && tableToSave.primaryDisplay === _rename.old) {
    ctx.throw(400, "Cannot rename the display column.")
  }

  tableToSave = await tableSaveFunctions.mid(tableToSave)

  // update schema of non-statistics views when new columns are added
  for (let view in tableToSave.views) {
    const tableView = tableToSave.views[view]
    if (!tableView) continue

    if (tableView.schema.group || tableView.schema.field) continue
    tableView.schema = tableToSave.schema
  }

  // update linked rows
  try {
    const linkResp = await linkRows.updateLinks({
      appId,
      eventType: oldTable
        ? linkRows.EventType.TABLE_UPDATED
        : linkRows.EventType.TABLE_SAVE,
      table: tableToSave,
      oldTable: oldTable,
    })
    if (linkResp != null && linkResp._rev) {
      tableToSave._rev = linkResp._rev
    }
  } catch (err) {
    ctx.throw(400, err)
  }

  // don't perform any updates until relationships have been
  // checked by the updateLinks function
  const updatedRows = tableSaveFunctions.getUpdatedRows()
  if (updatedRows && updatedRows.length !== 0) {
    await db.bulkDocs(updatedRows)
  }
  const result = await db.post(tableToSave)
  tableToSave._rev = result.rev

  tableToSave = await tableSaveFunctions.after(tableToSave)

  ctx.eventEmitter &&
    ctx.eventEmitter.emitTable(`table:save`, appId, tableToSave)

  ctx.status = 200
  ctx.message = `Table ${ctx.request.body.name} saved successfully.`
  ctx.body = tableToSave
}

exports.destroy = async function(ctx) {
  const appId = ctx.user.appId
  const db = new CouchDB(appId)
  const tableToDelete = await db.get(ctx.params.tableId)

  // Delete all rows for that table
  const rows = await db.allDocs(
    getRowParams(ctx.params.tableId, null, {
      include_docs: true,
    })
  )
  await db.bulkDocs(rows.rows.map(row => ({ ...row.doc, _deleted: true })))

  // update linked rows
  await linkRows.updateLinks({
    appId,
    eventType: linkRows.EventType.TABLE_DELETE,
    table: tableToDelete,
  })

  // don't remove the table itself until very end
  await db.remove(tableToDelete)

  // remove table search index
  const currentIndexes = await db.getIndexes()
  const existingIndex = currentIndexes.indexes.find(
    existing => existing.name === `search:${ctx.params.tableId}`
  )
  if (existingIndex) {
    await db.deleteIndex(existingIndex)
  }

  ctx.eventEmitter &&
    ctx.eventEmitter.emitTable(`table:delete`, appId, tableToDelete)
  ctx.status = 200
  ctx.body = { message: `Table ${ctx.params.tableId} deleted.` }
}

exports.validateCSVSchema = async function(ctx) {
  const { csvString, schema = {} } = ctx.request.body
  const result = await csvParser.parse(csvString, schema)
  ctx.body = { schema: result }
}