import Debug from "debug";
import { mkdirSync, writeFileSync } from "fs";

import { getFlag } from "./nocs";
import { Calendar } from "./types";

export class ICSGenerator {
  private calendar: Calendar;

  private debug = Debug("olympics-calendar:ics-generator");

  constructor(calendar: Calendar) {
    this.calendar = calendar;
  }

  private cleanLine(line: string): string {
    if (line.length <= 75) {
      return line;
    }
    const chunks: string[] = [];
    let index = 0;
    while (index < line.length) {
      let chunk = line.slice(index, index + 75);
      if (index > 0) {
        chunk = "  " + chunk.trim();
      }
      chunks.push(chunk);
      index += 75;
    }
    return chunks.join("\n");
  }

  private generateICSFile(
    sportKey: string | null,
    nocKey: string | null,
  ): void {
    this.debug(
      "generateICSFile",
      sportKey || "all-sports",
      nocKey || "all-nocs",
    );

    for (const lang of this.calendar.languages) {
      const pathSportKey = sportKey ? sportKey : "all-sports";
      const pathNocKey = nocKey ? nocKey : "calendar";

      const filepath = `./output/${lang.code.toLowerCase()}/${pathSportKey.toLowerCase()}/${pathNocKey.toLowerCase()}.ics`;
      mkdirSync(filepath.split("/").slice(0, -1).join("/"), { recursive: true });

      const titleComponents: string[] = [];
      if (nocKey) {
        titleComponents.push(
          `${this.calendar.nocs.find((n) => n.key === nocKey)!.name[lang.code]}`,
        );
      }
      if (sportKey) {
        titleComponents.push(this.calendar.sports.find((s) => s.key === sportKey)!.name[lang.code] || "");
      }
      titleComponents.push("Milano Cortina 2026");

      const title = titleComponents.join(" - ");

      const lines: string[] = [];

      lines.push("BEGIN:VCALENDAR");
      lines.push("VERSION:2.0");
      lines.push(
        `PRODID:-//fabrice404//olympics-calendar//${lang.code}/${pathSportKey}/${pathNocKey}`,
      );
      lines.push(`X-WR-CALNAME:${title}`);
      lines.push(`NAME:${title}`);

      this.calendar.events
        .filter((event) => {
          if ((sportKey && event.sport !== sportKey) || event.sport === "CER") {
            return false;
          }
          if (nocKey && !event.nocs.includes(nocKey)) {
            return false;
          }
          return true;
        })
        .forEach((event) => {
          lines.push("BEGIN:VEVENT");
          lines.push(`UID:${event.key.replace(/--/g, "-")}`);
          lines.push(`DTSTAMP:${event.start.replace(/[-:]/g, "").replace(/\.\d+Z$/, "Z")}`);
          lines.push(`DTSTART:${event.start.replace(/[-:]/g, "").replace(/\.\d+Z$/, "Z")}`);
          lines.push(`DTEND:${event.end.replace(/[-:]/g, "").replace(/\.\d+Z$/, "Z")}`);
          lines.push(`LOCATION:${event.location[lang.code] || ""}`);

          const sport = this.calendar.sports.find(
            (s) => s.key === event.sport,
          )!;
          let description = `DESCRIPTION:${sport.name[lang.code]} - ${event.name[lang.code] || ""}`;
          let summary = `SUMMARY:${event.name[lang.code] || ""}`;

          if (event.competitors?.length === 2) {
            const competitor1 = this.getCompetitor(event.competitors[0]!, lang.code);
            const competitor2 = this.getCompetitor(event.competitors[1]!, lang.code);

            if (competitor1 && competitor2) {
              summary = `SUMMARY:${competitor1?.flag} ${competitor1.name} - ${competitor2?.name} ${competitor2.flag}`;
            }
          } else if (event.competitors?.length > 0) {
            const competitors = event.competitors
              .map((competitorId) => this.getCompetitor(competitorId, lang.code))
              .map((competitor) => `\\n${competitor.flag} ${competitor.name}`).join("");
            description += `${competitors}`;

          }

          lines.push(summary);
          lines.push(this.cleanLine(description));
          lines.push("END:VEVENT");
        });

      lines.push("END:VCALENDAR");

      if (lines.length <= 10) {
        this.debug("Skipping empty ICS file:", filepath);
      } else {
        writeFileSync(filepath, lines.join("\n"), "utf-8");
      }
    }
  }

  private getCompetitor(competitorId: string, lang: string) {
    if (competitorId.startsWith("team:")) {
      const team = this.calendar.nocs.find(noc => noc.key === competitorId.replace("team:", ""));
      return {
        noc: team?.key,
        name: team?.name[lang] || team?.key || competitorId,
        flag: getFlag(team?.key || ""),
      };
    }
    const competitor = this.calendar.competitors.find(comp => comp.code === competitorId)!;
    return {
      noc: competitor.noc,
      name: competitor.name,
      flag: getFlag(competitor.noc),
    };
  }

  public generate(): void {
    this.debug("generate");
    this.generateICSFile(null, null);

    this.calendar.sports.forEach((sport) => {
      this.generateICSFile(sport.key, null);
      this.calendar.nocs.forEach((noc) => {
        this.generateICSFile(sport.key, noc.key);
      });
    });

    this.calendar.nocs.forEach((noc) => {
      this.generateICSFile(null, noc.key);
    });
  }
}