// Functions to calculate metrics over sessions
import {
  ChatSession,
  DayMetrics,
  CategoryMetrics,
  LanguageMetrics,
  MetricsResult,
} from "./types";

interface CompanyConfig {
  sentimentAlert?: number;
}

export function sessionMetrics(
  sessions: ChatSession[],
  companyConfig: CompanyConfig = {},
): MetricsResult {
  const total = sessions.length;
  const byDay: DayMetrics = {};
  const byCategory: CategoryMetrics = {};
  const byLanguage: LanguageMetrics = {};
  let escalated = 0,
    forwarded = 0;
  let totalSentiment = 0,
    sentimentCount = 0;
  let totalResponse = 0,
    responseCount = 0;
  let totalTokens = 0,
    totalTokensEur = 0;

  // Calculate total session duration in minutes
  let totalDuration = 0;
  let durationCount = 0;

  sessions.forEach((s) => {
    const day = s.startTime.toISOString().slice(0, 10);
    byDay[day] = (byDay[day] || 0) + 1;

    if (s.category) byCategory[s.category] = (byCategory[s.category] || 0) + 1;
    if (s.language) byLanguage[s.language] = (byLanguage[s.language] || 0) + 1;

    if (s.endTime) {
      const duration =
        (s.endTime.getTime() - s.startTime.getTime()) / (1000 * 60); // minutes
      totalDuration += duration;
      durationCount++;
    }

    if (s.escalated) escalated++;
    if (s.forwardedHr) forwarded++;

    if (s.sentiment != null) {
      totalSentiment += s.sentiment;
      sentimentCount++;
    }

    if (s.avgResponseTime != null) {
      totalResponse += s.avgResponseTime;
      responseCount++;
    }

    totalTokens += s.tokens || 0;
    totalTokensEur += s.tokensEur || 0;
  });

  // Now add sentiment alert logic:
  let belowThreshold = 0;
  const threshold = companyConfig.sentimentAlert ?? null;
  if (threshold != null) {
    for (const s of sessions) {
      if (s.sentiment != null && s.sentiment < threshold) belowThreshold++;
    }
  }

  // Calculate average sessions per day
  const dayCount = Object.keys(byDay).length;
  const avgSessionsPerDay = dayCount > 0 ? total / dayCount : 0;

  // Calculate average session length
  const avgSessionLength =
    durationCount > 0 ? totalDuration / durationCount : null;

  return {
    totalSessions: total,
    avgSessionsPerDay,
    avgSessionLength,
    days: byDay,
    languages: byLanguage,
    categories: byCategory,
    belowThresholdCount: belowThreshold,
    // Additional metrics not in the interface - using type assertion
    escalatedCount: escalated,
    forwardedCount: forwarded,
    avgSentiment: sentimentCount ? totalSentiment / sentimentCount : null,
    avgResponseTime: responseCount ? totalResponse / responseCount : null,
    totalTokens,
    totalTokensEur,
    sentimentThreshold: threshold,
    lastUpdated: Date.now(), // Add current timestamp
  } as MetricsResult;
}