const mysql = require("mysql2/promise")

const searchLib = require("./search")
const {host, port, user, database, password} = require("./../settings").db

/////////////////////////////////////////////////////////////////////////

let poolP = initPool()

async function initPool () {
   return mysql.createPool({
      host,
      port,
      database,
      user,
      password,
   })
}

/////////////////////////////////////////////////////////////////////////

module.exports = {
   getUsers,
   getUserCount,
   getUserByLogin,
   getUserByUserId,
   getUserDefinedFields,
   getUserDefinedField,
   getUserTeilnahmen,

   getObjIdFromRefId,
   getRefIdFromObjId,

   getKurse,
   getKurs,
   getKursItems,
   getKursItems2,
   // getKursByObjId,
   // getKursByRefId,
   getKursTeilnehmer,
   getKursTeilnehmerCount,

   getUdf,

   getMemberRoleForCourse,
}

/////////////////////////////////////////////////////////////////////////

async function getUserSearchQuery (offset, limit, search) {
   const sel = `usr_id, login, firstname, lastname, gender, email, institution, street, city, zipcode, country, department, active`
   if (!search || search === '') {
      return `SELECT ${sel}
              FROM ${database}.usr_data AS ud
              WHERE login REGEXP '^[0-9]+$'
              LIMIT ${limit}
              OFFSET ${offset}
      `
   }
   else {
      const ids = await searchLib.search(search)
      if (!ids.length) {
         throw "nothing found"
         return await getUserSearchQuery(offset, limit)
      } // nothing found
      return `SELECT ${sel}
              FROM ${database}.usr_data AS ud
              WHERE login REGEXP '^[0-9]+$'
              AND usr_id IN (${ids.join(",")})
                  LIMIT ${limit}
              OFFSET ${offset}
      `
   }
}

async function getUsers (offset = 0, limit = 10, search = null) {
   console.log("++++++++++ get users", offset, limit, search)
   limit = Number(limit) || 10
   offset = Number(offset) || 0
   // TODO check args for SQL Injection

   const pool = await poolP

   try {
      let userSearchQuery = await getUserSearchQuery(offset, limit, search)
      // console.log(userSearchQuery)
      const [results, fields] = await pool.query(userSearchQuery)
      const count = await getUserCount(offset, limit, search)
      return {
         total: count,
         offset, limit,
         data: results,
      }
   } catch (ex) {
      return {
         total: 0,
         offset: 0,
         limit: 0,
         data: [],
      }
   }
}

async function getUserCount (offset, limit, search) {
   const pool = await poolP
   // const q = getUserSearchQuery(offset, limit, search)
   const q = await getUserSearchQuery(0, 1000000, search) // hier darf kein Limit sein, offset=0
   const q2 = `SELECT COUNT(*) AS count
               FROM (${q}) AS X`
   const [results, fields] = await pool.query(q2)
   return results[0].count

   // const [results, fields] = await pool.query(
   //    `SELECT COUNT(*)
   //     FROM ${database}.usr_data AS ud
   //     WHERE login REGEXP '^[0-9]+$'`
   // )
   // return results[0]["COUNT(*)"]
}

async function getUserByLogin (login) {
   const sel = `usr_id, login, firstname, lastname, gender, email, institution, street, city, zipcode, country, department, active`
   // TODO check args for SQL Injection

   const pool = await poolP
   const [results, fields] = await pool.query(
      `SELECT ${sel}
       FROM ${database}.usr_data AS ud
       WHERE login = '${login}'`
   )
   return joinUDF(results[0])
}

async function getUserByUserId (userId) {
   const sel = `usr_id, login, firstname, lastname, gender, email, institution, street, city, zipcode, country, department, active`
   // TODO check args for SQL Injection

   const pool = await poolP
   const [results, fields] = await pool.query(
      `SELECT ${sel}
       FROM ${database}.usr_data AS ud
       WHERE usr_id = '${userId}'`
   )
   return joinUDF(results[0])
}

async function getUserDefinedFields () {
   const pool = await poolP
   const [results] = await pool.query(
      `SELECT ut.usr_id, ud.field_name, ut.value
       FROM ${database}.udf_definition ud
                JOIN ${database}.udf_text ut ON ut.field_id = ud.field_id`
   )
   return results
}

async function getUserDefinedField (usr_id) {
   const pool = await poolP
   const [results] = await pool.query(
      `SELECT ut.usr_id, ud.field_name, ut.value
       FROM ${database}.udf_definition ud
                JOIN ${database}.udf_text ut ON ut.field_id = ud.field_id
       WHERE ut.usr_id = '${usr_id}'
      `
   )
   return results
}

/////// obj_id / ref_id ////////////////////////////////////////////////////////////////

async function getObjIdFromRefId (refId) {
   const pool = await poolP
   const [results] = await pool.query(
      `SELECT ref_id, obj_id
       FROM ${database}.object_reference as obr
       WHERE obr.ref_id = ${refId}
      `
   )
   return results.length ? results[0] : undefined
}

async function getRefIdFromObjId (objId) {
   const pool = await poolP
   const [results] = await pool.query(
      `SELECT ref_id, obj_id
       FROM ${database}.object_reference as obr
       WHERE obr.obj_id = ${objId}
      `
   )
   return results.length ? results[0] : undefined
}

/////////////////////////////////////////////////////////////////////////

async function promiseDelay (ms) {
   return new Promise(resolve => setTimeout(resolve, ms))
}

async function joinUDF (user) {
   if (!user) return user
   const fields = await getUserDefinedField(user.usr_id)
   for (const field of fields) {
      user[field.field_name] = field.value
   }
   return user
}

/////// Kurs ////////////////////////////////////////////////////////////////

async function getKurse () {
   const pool = await poolP
   const q = `SELECT or2.ref_id, or2.obj_id, od.title, od.description, od.type
              FROM ${database}.object_reference or2
                       INNER JOIN ${database}.object_data od ON od.obj_id = or2.obj_id
              WHERE od.type = 'crs'
                AND or2.deleted IS NULL
   `
   const [results] = await pool.query(q)
   return results
}

// async function getKursByRefId (refId) {
//    const {ref_id, obj_id} = await getObjIdFromRefId(refId)
//    return getKursByObjId(obj_id)
// }

async function getKurs (ref_id) {
   const pool = await poolP
   const q = `SELECT or2.ref_id, or2.obj_id, od.title, od.description, od.type, od.create_date
              FROM ${database}.object_reference or2
                       INNER JOIN ${database}.object_data od ON od.obj_id = or2.obj_id
              WHERE or2.ref_id = '${ref_id}'
   `
   let [results] = await pool.query(q)
   results = results.length ? results[0] : undefined
   return results
}

async function getKursItems (ref_id) {
   const pool = await poolP
   // const q = `SELECT or2.ref_id, or2.obj_id, od.title, od.description, od.type
   //            FROM ${database}.object_reference or2
   //            INNER JOIN ${database}.object_data od ON od.obj_id = or2.obj_id
   //            WHERE or2.obj_id = '${obj_id}'
   // `
   const q = `SELECT ci.parent_id, or2.ref_id, or2.obj_id, od.title, od.type
              FROM ${database}.crs_items ci
                       INNER JOIN ${database}.object_reference or2 ON or2.ref_id = ci.obj_id
                       INNER JOIN ${database}.object_data od ON od.obj_id = or2.obj_id
              WHERE or2.ref_id = ${ref_id}
                 OR parent_id = ${ref_id}
                  AND or2.deleted is NULL
   `
   const [results] = await pool.query(q)
   return results
}

async function getKursItems2 (ref_id) {
   const pool = await poolP
   const q = `
       WITH RECURSIVE tree (parent_id, obj_id, ref_id, title, type) AS
                          (SELECT ci.parent_id,
                                  or2.obj_id,
                                  ci.obj_id as ref_id,
                                  od.title,
                                  od.type
                           FROM ${database}.crs_items ci
                                    INNER JOIN ${database}.object_reference or2 ON or2.ref_id = ci.obj_id
                                    INNER JOIN ${database}.object_data od ON od.obj_id = or2.obj_id
                           WHERE ci.obj_id = ${ref_id} -- Kurs ref_id
                             AND or2.deleted is NULL

                           UNION ALL

                           SELECT child.parent_id,
                                  or2.obj_id,
                                  child.obj_id as ref_id,
                                  od.title,
                                  od.type
                           FROM ${database}.crs_items child
                                    INNER JOIN ${database}.object_reference or2 ON or2.ref_id = child.obj_id
                                    INNER JOIN ${database}.object_data od ON od.obj_id = or2.obj_id
                                    JOIN tree ON child.parent_id = tree.ref_id
                           WHERE or2.deleted is NULL)
       SELECT *
       FROM tree
       ORDER BY tree.ref_id
   `
   const [results] = await pool.query(q)
   return results
}

async function getKursTeilnehmer (ref_id) {
   const pool = await poolP
   const q = `SELECT ci.parent_id,
                     or2.ref_id,
                     or2.obj_id,
                     od.title,
                     od.type,
                     om.usr_id,
                     ud.login,
                     ud.firstname,
                     ud.lastname,
                     ud.active,
                     om.passed,
                     ulm.status,
                     ulm.status_changed
              FROM ${database}.crs_items ci
                       INNER JOIN ${database}.object_reference or2 ON or2.ref_id = ci.obj_id
                       INNER JOIN ${database}.object_data od ON od.obj_id = or2.obj_id
                       INNER JOIN ${database}.obj_members om ON om.obj_id = or2.obj_id AND om.member = 1
                       INNER JOIN ${database}.usr_data ud ON ud.usr_id = om.usr_id
                       LEFT JOIN ${database}.ut_lp_marks ulm ON ulm.obj_id = or2.obj_id AND ud.usr_id = ulm.usr_id
              WHERE (or2.ref_id = ${ref_id} OR parent_id = ${ref_id})
              ORDER BY usr_id
   `
   console.log(q)
   const [results] = await pool.query(q)
   return results
}

async function getKursTeilnehmerCount (ref_id) {
   const pool = await poolP
   const q = `SELECT COUNT(*) as count
              FROM ${database}.crs_items ci
                  INNER JOIN ${database}.object_reference or2
              ON or2.ref_id = ci.obj_id
                  INNER JOIN ${database}.object_data od ON od.obj_id = or2.obj_id
                  INNER JOIN ${database}.obj_members om ON om.obj_id = or2.obj_id AND om.member = 1
                  INNER JOIN ${database}.usr_data ud ON ud.usr_id = om.usr_id
                  LEFT JOIN ${database}.ut_lp_marks ulm ON ulm.obj_id = or2.obj_id AND ud.usr_id = ulm.usr_id
              WHERE (or2.ref_id = ${ref_id}
                 OR parent_id = ${ref_id})
              ORDER BY usr_id
   `
   let [results] = await pool.query(q)
   results = results.length ? results[0] : undefined
   return {ref_id, count: results.count}
}

async function getUserTeilnahmen (usr_id) {
   const pool = await poolP
   const q = `SELECT om.obj_id, or2.ref_id, om.usr_id, od.title, ulm.status, om.passed, ulm.status_changed
              FROM ${database}.obj_members om
                       INNER JOIN ${database}.object_reference or2 ON or2.obj_id = om.obj_id
                       INNER JOIN ${database}.usr_data ud ON ud.usr_id = om.usr_id
                       INNER JOIN ${database}.object_data od ON od.obj_id = om.obj_id
                       LEFT JOIN ${database}.ut_lp_marks ulm
                                 ON ulm.usr_id = om.usr_id AND ulm.obj_id = om.obj_id
              WHERE om.usr_id = ${usr_id}
                AND om.member = 1
   `
   console.log(q)
   const [results] = await pool.query(q)
   return results
}

/////// UDF ////////////////////////////////////////////////////////////////

async function getUdf () {
   const pool = await poolP
   const q = `SELECT field_id, field_name, field_type
              from ${database}.udf_definition;`
   const [results] = await pool.query(q)
   return results
}

/////// ROLLEN ////////////////////////////////////////////////////////////////

async function getMemberRoleForCourse (obj_id) {
   const pool = await poolP
   const q = `SELECT obj_id, title, description
              from object_data od
              WHERE type = "role" #AND title LIKE 'il_crs_member_157'
                AND od.description LIKE 'Member%${obj_id}'
   `
   const [results] = await pool.query(q)
   // darf nur einen Treffer ergeben
   if (results.length) {
      const {obj_id, title, description} = results[0]
      return obj_id
   }
   else {
      return null
   }
}