import Prisma from "@prisma/client";
import axios from "axios";
import { log, getLogPath } from "../logs.js";
import { getAuthtoken, getTimetables } from "./dsbmobile.js";
import { parseSubstitutionPlan } from "./untis.js";
import fs from "fs";

const prisma = new Prisma.PrismaClient();

const dsbFiles = ["Schüler_Monitor - subst_001", "Schüler Morgen - subst_001"];

export class Parser {
  dsbUser;
  dsbPassword;
  constructor(dsbUser, dsbPassword, interval) {
    this.dsbUser = dsbUser;
    this.dsbPassword = dsbPassword;

    setInterval(() => this.updatePlan(), interval);
    this.updatePlan();
  }
  async updatePlan() {
    const startedAt = new Date();
    try {
      const data = await this.fetchDSB();
      if (!data) {
        throw "DSB request failed!";
      }
      const plans = [];
      for (const entry of data) {
        const data = await this.fetchFile(entry.url);
        const parsed = parseSubstitutionPlan(data);
        plans.push(parsed);
      }
      const parseEvent = await prisma.parseEvent.create({
        data: {
          logFile: getLogPath(),
          originalData: "",
          duration: new Date() - startedAt,
          succeeded: true,
        },
      });
      for (const plan of plans) {
        await this.insertSubstitutions(plan, parseEvent);
      }
    } catch (error) {
      await prisma.parseEvent.create({
        data: {
          logFile: getLogPath(),
          originalData: error.toString(),
          duration: new Date() - startedAt,
          succeeded: false,
        },
      });
      log("Parser / Main", "Parse event failed: " + error);
    }
  }
  async fetchDSB() {
    try {
      const token = await getAuthtoken(this.dsbUser, this.dsbPassword);
      const response = await getTimetables(token);
      const timetables = response.filter((e) => dsbFiles.includes(e.title));
      return timetables;
    } catch (error) {
      log("Parser / DSB Mobile", "Error getting data: " + error);
    }
    return false;
  }
  async fetchFile(url) {
    const result = await axios.request({
      method: "GET",
      url: url,
      responseEncoding: "binary",
    });
    return result.data;
  }
  async parsePlan(html) {
    return parseSubstitutionPlan(html);
  }
  async insertSubstitutions(parsedData, parseEvent) {
    const { updatedAt, date, changes } = parsedData;
    const classList = await prisma.class.findMany();

    const knownSubstitutions = await prisma.substitution.findMany({
      where: {
        date: new Date(new Date(date).setUTCHours(0, 0, 0, 0)),
        removed: false,
      },
    });

    for (const change of changes) {
      const classes = this.getSubstitutionClasses(classList, change.class);
      if (classes.length == 0) classes.push(change.class || "unknown");

      // Workaround no currect match possible for subsitutions of this
      // type beacuse they don't have a class and a subject attribute
      if (change.type == "Sondereins." && !change.subject) {
        change.subject = change.notes;
      }

      const matchingSubstitutionId = knownSubstitutions.findIndex(
        (substitution) => {
          return substitution.date == new Date(date).setUTCHours(0, 0, 0, 0) &&
            substitution.type == (change.type == "Entfall")
            ? "cancellation"
            : "change" &&
                substitution.lesson == change.lesson &&
                classes.sort().join(",") ==
                  substitution.class.sort().join(",") &&
                substitution.changedSubject == change.subject;
        }
      );
      const matchingSubstitution = knownSubstitutions[matchingSubstitutionId];

      if (!matchingSubstitution) {
        const newSubstitution = await prisma.substitution.create({
          data: {
            class: classes,
            date: new Date(date),
            type: change.type == "Entfall" ? "cancellation" : "change",
            lesson: parseInt(change.lesson),
            changedTeacher: change.changedTeacher,
            changedRoom: change.room || undefined,
            changedSubject: change.subject,
            notes: change.notes,
            removed: false,
          },
        });
        const substitutionChange = await prisma.substitutionChange.create({
          data: {
            substitutionId: newSubstitution.id,
            type: "addition",
            changes: {
              class: classes,
              type: change.type == "Entfall" ? "cancellation" : "change",
              lesson: parseInt(change.lesson),
              date: new Date(date),
              change: {
                teacher: change.changedTeacher,
                room: change.room || undefined,
                subject: change.subject,
              },
            },
            parseEventId: parseEvent.id,
          },
        });
        log(
          "Insert / DB",
          `Created new substitution: S:${newSubstitution.id} C:${substitutionChange.id}`
        );
      } else {
        const differences = this.findDifferences(matchingSubstitution, change);
        if (Object.keys(differences).length > 0) {
          const prismaOptions = {
            where: {
              id: matchingSubstitution.id,
            },
            data: {},
          };
          if (differences.teacher)
            prismaOptions.data.changedTeacher = change.changedTeacher;
          if (differences.room) prismaOptions.data.changedRoom = change.room;
          if (differences.notes) prismaOptions.data.notes = change.notes;

          await prisma.substitution.update(prismaOptions);
          const substitutionChange = await prisma.substitutionChange.create({
            data: {
              substitutionId: matchingSubstitution.id,
              type: "change",
              changes: differences,
              parseEventId: parseEvent.id,
            },
          });
          log(
            "Insert / DB",
            `Found changed substitution: S:${matchingSubstitution.id} C:${substitutionChange.id}`
          );
        } else {
          log(
            "Insert / DB",
            `Substitution unchanged: S:${matchingSubstitution.id}`
          );
        }
        knownSubstitutions.splice(matchingSubstitutionId, 1);
      }
    }
    for (const remainingSubstitution of knownSubstitutions) {
      await prisma.substitution.update({
        where: {
          id: remainingSubstitution.id,
        },
        data: {
          removed: true,
        },
      });
      const substitutionChange = await prisma.substitutionChange.create({
        data: {
          substitutionId: remainingSubstitution.id,
          type: "deletion",
          changes: {},
          parseEventId: parseEvent.id,
        },
      });
      log(
        "Insert / DB",
        `Deleted removed substitution: S:${remainingSubstitution.id} C:${substitutionChange.id}`
      );
    }
  }
  getSubstitutionClasses(classList, classString) {
    const matchingClasses = classList.filter((element) => {
      const regex = new RegExp(element.regex);
      return (classString || "").toLowerCase().match(regex);
    });
    return matchingClasses.map((e) => e.name);
  }
  findDifferences(currentSubstitution, newChange) {
    const differences = {};
    if (newChange.changedTeacher != currentSubstitution.changedTeacher) {
      differences.teacher = {
        before: currentSubstitution.changedTeacher,
        after: newChange.changedTeacher,
      };
    }
    if (newChange.room != currentSubstitution.changedRoom) {
      differences.room = {
        before: currentSubstitution.changedRoom,
        after: newChange.room,
      };
    }
    if (newChange.notes != currentSubstitution.notes) {
      differences.notes = {
        before: currentSubstitution.notes,
        after: newChange.notes,
      };
    }
    return differences;
  }
}