import { defineStore } from "pinia";
import { useToast } from "vue-toastification";
import {
  CalendarEvent,
  TaughtClass,
  Module,
  PersonalEvent,
  PlanningDump,
  PlanEntry,
} from "../types";
import { useClassesStore } from "./classes";
import { useModulesStore } from "./modules";
import { useClassVersionStore } from "./ClassVersion";
import { useStateStore } from "./state";
import {
  semesterVersionStringC,
  waitTimeAfterOldPlanReminder,
  waitTimeAfterUpgradeRequestModal,
} from "../helpers";

const MAX_MODULE_COUNT = 40;
const toast = useToast();

function otherPlanModificationToast() {
  toast.error("Du kannst den Plan eines anderen nicht bearbeiten");
}

function reloadChosenModules() {
  const planningStore = usePlanningStore();
  planningStore.loadChosen();
}

const DEFAULT_PLAN_NAME = "default";

export const BLOCKCOURSE_DAY_IDX = 6;
export const usePlanningStore = defineStore("planning", {
  state: () => {
    return {
      usingModulesFromURL: false,
      chosen: [] as TaughtClass[],
      personalEvents: [] as PersonalEvent[],
      hourStart: 8,
      hourEnd: 22,
      hourDivisions: 2,
      cellHeight: 24,
      get currentPlanName(): string {
        if (this.__currentPlanName != null) return this.__currentPlanName;
        let name = localStorage["lastSelectedCalendarSet"];
        if (!name) {
          name = DEFAULT_PLAN_NAME;
          localStorage["lastSelectedCalendarSet"] = DEFAULT_PLAN_NAME;
        }
        this.__currentPlanName = name;
        return name;
      },
      set currentPlanName(newName: string) {
        this.__currentPlanName = newName;
        localStorage["lastSelectedCalendarSet"] = newName;
        reloadChosenModules();
      },
      __currentPlanName: null as string | null,
      allPlans: [] as PlanEntry[],
      saveChanges: true,
      lastPlanRequestTimestamp: undefined as undefined | number,
      oldPlanReminderTimestamp: undefined as undefined | number,
      doNotRequestVersionUpgrade: false,
    };
  },

  getters: {
    eventsByDay(): CalendarEvent[][] {
      // Prefill with 7, because school is from Mo-Sa (6) + 1 day for the block courses
      const events = new Array(7).fill(null).map(() => []) as CalendarEvent[][];

      const allPlacable = [...this.chosen, ...this.personalEvents];

      // Sort by longest duration, we want to have them leftmost on the calendar view
      const ch = allPlacable
        .filter((el) => el != null)
        .sort((a, b) => b.to - b.from - (a.to - a.from));

      ch.forEach((m, idx) => {
        const topOffset =
          (m.from / 3600 - this.hourStart) *
          this.cellHeight *
          this.hourDivisions;
        const length =
          ((m.to - m.from) / 3600) * this.cellHeight * this.hourDivisions;

        let overlapCount = 0;
        let overlapIdx = 0;
        ch.forEach((om, oidx) => {
          if (m.weekday != om.weekday || idx == oidx) return;

          if (om.from >= m.from && om.from <= m.to) {
            overlapCount++;
            if (idx > oidx) overlapIdx++;
          } else if (m.from >= om.from && m.from <= om.to) {
            overlapCount++;
            if (idx > oidx) overlapIdx++;
          }
        });

        const width = 100 / (overlapCount + 1) - overlapIdx;
        const leftOffset = overlapIdx * width + overlapIdx;

        let tc = null as null | TaughtClass;
        let pe = null as null | PersonalEvent;

        if ((m as TaughtClass).teachers) tc = m as TaughtClass;
        else pe = m as PersonalEvent;

        events[m.weekday ?? BLOCKCOURSE_DAY_IDX].push({
          taughtClass: tc,
          personalEvent: pe,
          topOffset: topOffset,
          leftOffset: leftOffset,
          length: length,
          width: width,
        });
      });

      return events;
    },
    sharedDisplayName(): string | null {
      if (!this.usingModulesFromURL) return null;

      const pn = this.currentPlanName;
      if (pn.length == 0 || pn == DEFAULT_PLAN_NAME) return null;
      return pn;
    },
    totalECTSCount(): { ects: number; unsureModules: string[] } {
      let ects = 0;
      const unsureModules = [] as string[];

      const countedModules = [] as string[];
      this.chosen.forEach((c) => {
        const module = c.module;
        if (module == null || module.ects == null) {
          unsureModules.push(c.name);
          return;
        }

        const moduleName = module.name;
        if (countedModules.indexOf(moduleName) == -1) {
          ects += module.ects;
          countedModules.push(moduleName);
        }
      });
      this.personalEvents.forEach((pe) => (ects += pe.ects ?? 0));

      return { ects, unsureModules };
    },
    modulesWithMSP(): Module[] {
      const modulesStore = useModulesStore();
      return this.chosen
        .map((c) => modulesStore.fromModuleShort(c.name))
        .filter((m) => m?.hasMSP === true) as Module[];
    },
    ectsInBBVTClasses(): { bb: number; vt: number } {
      const res = { bb: 0, vt: 0 };
      const seen = { bb: [], vt: [] } as { bb: string[]; vt: string[] };

      this.chosen.forEach((c) => {
        const moduleName = c.name;
        const ects = c.module?.ects ?? 0;

        if (c.isBB) {
          const found = seen.bb.indexOf(moduleName) >= 0;
          if (found) return;
          seen.bb.push(moduleName);

          res.bb += ects;
        } else {
          const found = seen.vt.indexOf(moduleName) >= 0;
          if (found) return;
          seen.vt.push(moduleName);

          res.vt += ects;
        }
      });
      return res;
    },
    ectsInEngClasses(): number {
      const seen = [] as string[];
      return this.chosen
        .filter((c) => {
          const moduleName = c.name;
          const found = seen.indexOf(moduleName) >= 0;
          if (!found) seen.push(moduleName);
          return found;
        })
        .reduce((sum, c) => sum + (c.isEnglish ? c.module?.ects ?? 0 : 0), 0);
    },
    ectsInContextClasses(): number {
      const seen = [] as string[];
      return this.chosen
        .filter((c) => {
          const moduleName = c.name;
          const found = seen.indexOf(moduleName) >= 0;
          if (!found) seen.push(moduleName);
          return found;
        })
        .reduce((sum, c) => sum + (c.isContext ? c.module?.ects ?? 0 : 0), 0);
    },
    ectsWithMSP(): number {
      const seen = [] as string[];
      return this.chosen
        .filter((c) => {
          const moduleName = c.name;
          const found = seen.indexOf(moduleName) >= 0;
          if (!found) seen.push(moduleName);
          return found;
        })
        .reduce(
          (sum, c) => sum + (c.module?.hasMSP ? c.module?.ects ?? 0 : 0),
          0,
        );
    },
  },

  actions: {
    /**
     * Updates the current plan from using the old ids in the format of
     * `<className>-<name>-<weekday>-<room1<_room2, ...>>` to
     * `<className>-<name>-<weekday>-<from_time>-<to_time>`.
     *
     * This function and it's calls can be safely (and should be) removed by the end of
     * 2023! In addition to this code, some further code in `loadChosen` can also be
     * removed (marked).
     */
    checkAndUpdateChosenIDs(modules: string[]): string[] {
      const newIdRE = /^.*-.*-\d-\d+-\d+$/;
      const classesStore = useClassesStore();
      const currentClasses = [
        ...(classesStore.currentData?.taughtClasses ?? []),
        ...(classesStore.currentData?.blockClasses ?? []),
      ];

      return modules.map((el) => {
        if (newIdRE.test(el)) return el;
        const split = el.split("-", 4);
        const cls = split[0];
        const name = split[1];
        const weekday = split[2];
        const rooms = split[3];

        // find the new id
        const found = currentClasses.filter(
          (c) =>
            c.class == cls &&
            c.name == name &&
            `${c.weekday}` == weekday &&
            c.rooms.join("_") == rooms,
        );

        if (found.length == 0) {
          console.warn("Failed to find a replacement ID!");
          return el;
        }

        return found[0].id;
      });
    },
    loadFromStorage() {
      // Saved plans
      this.allPlans = [] as PlanEntry[];
      for (const key in localStorage) {
        if (key.startsWith("moduleset-")) {
          const name = key.replace("moduleset-", "");
          if (name.length > 0) {
            const data = JSON.parse(
              localStorage[`moduleset-${name}`],
            ) as PlanningDump;
            const version = data.version;
            this.allPlans.push({ name, planVersion: version });
          }
        }
      }

      if (this.allPlans.length == 0) {
        this.createPlan(DEFAULT_PLAN_NAME);
        this.currentPlanName = DEFAULT_PLAN_NAME;
      }

      // Last selected plan
      this.loadChosen();
    },
    createPlan(name: string): boolean {
      if (this.allPlans.some((el) => el.name == name)) {
        toast.warning(
          `Der Plan '${name}' existiert bereits. Wähle einen anderen Namen.`,
        );
        return false;
      }

      const planVersion =
        semesterVersionStringC(useClassVersionStore().latestOverall) ?? "";
      this.allPlans.push({ name, planVersion });
      this.saveChosen(name, true);
      return true;
    },
    add(m: TaughtClass) {
      if (this.chosen.includes(m) || this.chosen.length > MAX_MODULE_COUNT)
        return;

      if (this.usingModulesFromURL) {
        otherPlanModificationToast();
        return;
      }

      this.chosen.push(m);
      this.saveChosen();
    },
    remove(m: TaughtClass) {
      if (this.usingModulesFromURL) {
        otherPlanModificationToast();
        return;
      }

      const idx = this.chosen.indexOf(m);
      if (idx == -1) return;
      this.chosen.splice(idx, 1);
      this.saveChosen();
    },
    removeIdx(idx: number) {
      if (this.usingModulesFromURL) {
        otherPlanModificationToast();
        return;
      }

      this.chosen.splice(idx, 1);
      this.saveChosen();
    },
    isModuleChosen(m: TaughtClass) {
      return this.chosen.includes(m);
    },
    saveChosen(name: string | null = null, forceEmpty = false) {
      if (!this.saveChanges) return;
      if (this.usingModulesFromURL) {
        console.log("Not saving the current plan, as this is a shared one!");
        return;
      }
      if (name == null) name = this.currentPlanName;
      localStorage[`moduleset-${name}`] = this.stateToJSON(forceEmpty);
    },
    loadChosen(name: string | null = null, useSavedVersion = true): boolean {
      if (name == null) name = this.currentPlanName;
      const params = window.location.href
        .substr(window.location.href.indexOf("?"))
        .replace("+", "%2B");
      const param = new URLSearchParams(params);

      let strData;
      const stateParam = param.get("state");
      if (stateParam) {
        const state = stateParam.replace("%2B", "+");
        strData = decodeURIComponent(escape(atob(state)));
        this.usingModulesFromURL = true;
      } else {
        strData = localStorage[`moduleset-${name}`];
        if (strData == null) return false;
        this.usingModulesFromURL = false;
      }

      const classVersionStore = useClassVersionStore();
      const modulesStore = useClassesStore();
      const data = JSON.parse(strData) as PlanningDump;

      classVersionStore.useFromPDFString(
        useSavedVersion
          ? data.version
          : useClassVersionStore().semVer ?? data.version,
      );
      modulesStore.fetchData();

      if (!modulesStore.currentData?.loaded) return false;

      this.doNotRequestVersionUpgrade =
        data.doNotRequestVersionUpgrade ?? false;

      let shouldSave = false;
      const cTimestamp = new Date().getTime();

      if (!this.doNotRequestVersionUpgrade) {
        this.lastPlanRequestTimestamp = data.lastPlanRequestTimestamp;
        if (
          !classVersionStore.isLatestSemesterVersion &&
          (this.lastPlanRequestTimestamp == undefined ||
            cTimestamp - this.lastPlanRequestTimestamp >
              waitTimeAfterUpgradeRequestModal)
        ) {
          const stateStore = useStateStore();
          stateStore.showingClassUpgradeModal = true;
          this.lastPlanRequestTimestamp = cTimestamp;
          shouldSave = true;
        }
      }

      this.oldPlanReminderTimestamp = data.oldPlanReminderTimestamp;
      if (
        !classVersionStore.isLatestSemester &&
        (this.oldPlanReminderTimestamp == undefined ||
          cTimestamp - this.oldPlanReminderTimestamp >
            waitTimeAfterOldPlanReminder)
      ) {
        const stateStore = useStateStore();
        stateStore.showingOldPlanReminderModal = true;
        this.oldPlanReminderTimestamp = cTimestamp;
        shouldSave = true;
      }

      /**
       * The following code can be removed at the end of 2023!
       */
      const updatedIDs = this.checkAndUpdateChosenIDs(data.modules);
      this.chosen = updatedIDs
        .map((el) => modulesStore.getById(el))
        .filter((el) => el) as TaughtClass[];
      /**
       * End code that can be removed at the end of 2023!
       */

      if (this.usingModulesFromURL) this.__currentPlanName = data.name ?? "";

      if (data.personalEvents) this.personalEvents = data.personalEvents;
      else this.personalEvents = [];

      /**
       * The following code can be removed at the end of 2023!
       */
      shouldSave ||= !(
        updatedIDs.length == data.modules.length &&
        updatedIDs.every(function (element, index) {
          return element === data.modules[index];
        })
      );
      /**
       * End code that can be removed at the end of 2023!
       */

      if (shouldSave) {
        console.log("Saving due to ...");
        this.saveChosen(name);
      }

      return true;
    },
    copySharedTo(name: string) {
      const params = window.location.href
        .substr(window.location.href.indexOf("?"))
        .replace("+", "%2B");
      const param = new URLSearchParams(params);
      const stateParam = param.get("state");
      if (!stateParam) return;

      const state = stateParam.replace("%2B", "+");
      const strData = decodeURIComponent(escape(atob(state)));
      localStorage[`moduleset-${name}`] = strData;

      window.history.pushState(null, "", window.location.href.split("?")[0]);
      this.currentPlanName = name;

      this.loadChosen(name);
    },
    deleteChosen(name: string | null = null): boolean {
      if (name == null) name = this.currentPlanName;
      const pIdx = this.allPlans.findIndex((el) => el.name == name);
      if (pIdx == -1) return false;

      this.allPlans.splice(pIdx, 1);
      localStorage.removeItem(`moduleset-${name}`);

      if (this.allPlans.length == 0) {
        const planVersion =
          semesterVersionStringC(useClassVersionStore().latestOverall) ?? "";
        this.allPlans.push({ name: DEFAULT_PLAN_NAME, planVersion });
        this.currentPlanName = DEFAULT_PLAN_NAME;
        this.chosen = [];
        this.saveChosen();
        this.loadChosen();
        return true;
      }

      if (this.currentPlanName == name)
        this.currentPlanName = this.allPlans[0].name;

      this.loadChosen();
      return true;
    },
    emptyPlan() {
      this.chosen = [];
      this.saveChosen();
    },
    copyPlan(
      copyName: string | null = null,
      copyFrom: string | null = null,
    ): string | null {
      if (copyFrom == null) copyFrom = this.currentPlanName;

      if (copyName == null) {
        let counter = 2;
        copyName = `Kopie von ${copyFrom}`;
        while (this.allPlans.findIndex((el) => el.name == copyName) >= 0) {
          copyName = `Kopie ${counter} von ${copyFrom}`;
          counter++;
        }
      } else {
        if (this.allPlans.findIndex((el) => el.name == copyName) >= 0) {
          // Key already exists
          toast.error(`Der Name '${copyName}' ist bereits vergeben!`);
          return null;
        }
      }

      if (localStorage[`moduleset-${copyFrom}`] == null) {
        // copyFrom name does not exist!
        toast.error(
          "Die zu kopierende Modulauswahl wurde nicht im Speicher gefunden!",
        );
        return null;
      }

      localStorage[`moduleset-${copyName}`] =
        localStorage[`moduleset-${copyFrom}`];

      const copyData = JSON.parse(
        localStorage[`moduleset-${copyName}`],
      ) as PlanningDump;

      this.allPlans.push({
        name: copyName,
        planVersion: copyData.version,
      });

      this.currentPlanName = copyName;
      return copyName;
    },
    renamePlan(newName: string, current: string | null = null): boolean {
      if (current == null) current = this.currentPlanName;
      if (current == newName) return true;

      if (localStorage[`moduleset-${newName}`] != null) {
        // Key already exists
        toast.error(`Der Name '${newName}' ist bereits vergeben!`);
        return false;
      }

      if (localStorage[`moduleset-${current}`] == null) {
        // Current name does not exist!
        toast.error(
          "Die zu umzubenennende Modulauswahl wurde nicht im Speicher gefunden!",
        );
        return false;
      }

      localStorage[`moduleset-${newName}`] =
        localStorage[`moduleset-${current}`];
      localStorage.removeItem(`moduleset-${current}`);
      this.currentPlanName = newName;

      const pIdx = this.allPlans.findIndex((el) => el.name == current);
      if (pIdx >= 0) {
        const planVersion = useClassVersionStore().semVer ?? "";
        this.allPlans.splice(pIdx, 1, { name: newName, planVersion });
      }

      return true;
    },
    stateToJSON(forceEmpty = false, includeName = false): string {
      let modules = [] as string[];
      if (!forceEmpty) modules = this.chosen.map((m) => m.id);

      const data = {
        version: useClassVersionStore().semVer,
        modules: modules,
        personalEvents: this.personalEvents,
        lastPlanRequestTimestamp: this.lastPlanRequestTimestamp,
        oldPlanReminderTimestamp: this.oldPlanReminderTimestamp,
        doNotRequestVersionUpgrade: this.doNotRequestVersionUpgrade,
      } as PlanningDump;

      if (includeName) data.name = this.currentPlanName;
      return JSON.stringify(data);
    },
    getShareURL(): string {
      const state = this.stateToJSON(false, true);
      const encodedState = btoa(unescape(encodeURIComponent(state)));
      return `${window.location.href}?state=${encodedState}`;
    },
    removePersonalEvent(event: PersonalEvent | null): boolean {
      if (event == null) return false;
      const idx = this.personalEvents.indexOf(event);
      if (idx == -1) return false;
      this.personalEvents.splice(idx, 1);
      this.saveChosen();

      return true;
    },
    addPersonalEvent(event: PersonalEvent) {
      this.personalEvents.push(event);
      this.saveChosen();
    },
    updatePersonalEvent(
      oldEvent: PersonalEvent,
      newEvent: PersonalEvent,
    ): boolean {
      const idx = this.personalEvents.indexOf(oldEvent);
      if (idx == -1) return false;
      this.personalEvents.splice(idx, 1, newEvent);
      this.saveChosen();

      return true;
    },
    noLongerRequestVersionUpgrade() {
      this.doNotRequestVersionUpgrade = true;
      this.saveChosen();
    },
  },
});