// ============================================================
// RAGU PHOTOGRAPHY — Cloudflare Worker
// Reads Google Sheet → calculates metrics → serves JSON API
// ============================================================

const SHEET_ID = '1ZJXklT-rZNKG5_FbiYbRDgAOMlrDtCJNeez2lsVFfbU';
const API_KEY  = 'AIzaSyAbgGPk-ZKgPvIZoAUQWjAGtlpMfP3Le3U';
const SHEET_TAB  = 'Customers';
const EVENTS_TAB = 'Events';

// Column indices (0-based) — must match setup_sheet.gs
const COL = {
  EVENT_ID:          0,   // A
  SEASON:            1,   // B
  EVENT_NAME:        2,   // C
  EVENT_DATE:        3,   // D
  ATHLETE_ID_GLOBAL: 4,   // E
  ATHLETE_ID_EVENT:  5,   // F
  ATHLETE_NAME:      6,   // G
  AGE_GROUP:         7,   // H
  SIGNUP_DATE:       8,   // I
  SIGNUP_TYPE:       9,   // J
  PARENT1_NAME:      10,  // K
  PARENT1_EMAIL:     11,  // L  ← identity key
  PARENT1_PHONE:     12,  // M
  PARENT2_NAME:      13,  // N
  PARENT2_EMAIL:     14,  // O
  PARENT2_PHONE:     15,  // P
  SHIPPING_ADDRESS:  16,  // Q
  NOTES:             17,  // R
  PREEVENT_CONTACT:  18,  // S
  PREEVENT_INTENT:   19,  // T
  DATE_PHOTOGRAPHED: 20,  // U
  FAMILY_FILM:       21,  // V
  FILM_PEOPLE:       22,  // W
  FIRST_SESSION:     23,  // X
  NUM_SESSIONS:      24,  // Y
  CUSTOMER_STATUS:   25,  // Z
  INTERNAL_STATUS:   26,  // AA
  WALL_ART:          27,  // AB
  BOOK:              28,  // AC
  MATTED_PRINT:      29,  // AD
  CUSTOM:            30,  // AE
  TOTAL_SPEND:       31,  // AF
  ARCHIVAL_PLAN:     32,  // AG
  FUTURE_ORDER:      33,  // AH
  CIRCLE_BACK_DATE:  34,  // AI
  CIRCLE_BACK_DAYS:  35,  // AJ
  TESTIMONIAL:       36,  // AK
  // Calculated cols (37-42) not parsed — computed in Worker instead
};

export default {
  async fetch(request) {
    const corsHeaders = {
      'Access-Control-Allow-Origin': '*',
      'Access-Control-Allow-Methods': 'GET, OPTIONS',
      'Access-Control-Allow-Headers': 'Content-Type',
      'Content-Type': 'application/json',
    };

    if (request.method === 'OPTIONS') {
      return new Response(null, { headers: corsHeaders });
    }

    try {
      const [rows, eventRows] = await Promise.all([
        fetchSheet(SHEET_TAB),
        fetchSheet(EVENTS_TAB),
      ]);

      const data   = parseCustomers(rows);
      const events = parseEvents(eventRows);

      const url = new URL(request.url);
      const selectedEvents = url.searchParams.get('events')
        ? url.searchParams.get('events').split(',').map(e => e.trim())
        : null;

      const filtered = selectedEvents
        ? data.filter(r => selectedEvents.includes(r.eventName))
        : data;

      const metrics = {
        summary:           calcSummary(filtered),
        funnel:            calcFunnel(filtered),
        aov:               calcAOV(filtered),
        byEvent:           calcByEvent(data),
        trends:            calcTrends(data, events),
        filmImpact:        calcFilmImpact(filtered),
        preEventImpact:    calcPreEventImpact(filtered),
        filmSizeImpact:    calcFilmSizeImpact(filtered),
        signupTypeImpact:  calcSignupTypeImpact(filtered),
        athleteRetention:  calcAthleteRetention(data),
        seasonTrends:      calcSeasonTrends(data),
        archival:          calcArchival(filtered),
        products:          calcProducts(filtered),
        circleBack:        calcCircleBack(filtered),
        events:            events,
        allEventNames:     [...new Set(data.map(r => r.eventName).filter(Boolean))].sort(),
        allSeasons:        [...new Set(data.map(r => r.season).filter(Boolean))].sort(),
        generatedAt:       new Date().toISOString(),
      };

      return new Response(JSON.stringify(metrics), { headers: corsHeaders });

    } catch (err) {
      return new Response(JSON.stringify({ error: err.message, stack: err.stack }), {
        status: 500,
        headers: corsHeaders,
      });
    }
  }
};

// ─────────────────────────────────────────────
// FETCH
// ─────────────────────────────────────────────
async function fetchSheet(tabName) {
  const range = encodeURIComponent(`${tabName}!A1:AQ10000`);
  const url = `https://sheets.googleapis.com/v4/spreadsheets/${SHEET_ID}/values/${range}?key=${API_KEY}`;
  const res = await fetch(url);
  if (!res.ok) throw new Error(`Sheets API ${res.status}: ${await res.text()}`);
  const json = await res.json();
  return json.values || [];
}

// ─────────────────────────────────────────────
// PARSE
// ─────────────────────────────────────────────
function parseCustomers(rows) {
  if (rows.length < 2) return [];
  return rows.slice(1).map(row => {
    const g = (i) => (row[i] || '').toString().trim();
    const n = (i) => parseFloat(g(i).replace(/[^0-9.-]/g, '')) || 0;
    return {
      eventId:          g(COL.EVENT_ID),
      season:           g(COL.SEASON),
      eventName:        g(COL.EVENT_NAME),
      eventDate:        g(COL.EVENT_DATE),
      athleteIdGlobal:  g(COL.ATHLETE_ID_GLOBAL),
      athleteIdEvent:   g(COL.ATHLETE_ID_EVENT),
      athleteName:      g(COL.ATHLETE_NAME),
      ageGroup:         g(COL.AGE_GROUP),
      signupDate:       g(COL.SIGNUP_DATE),
      signupType:       g(COL.SIGNUP_TYPE),
      parent1Name:      g(COL.PARENT1_NAME),
      parent1Email:     g(COL.PARENT1_EMAIL),
      parent1Phone:     g(COL.PARENT1_PHONE),
      parent2Name:      g(COL.PARENT2_NAME),
      parent2Email:     g(COL.PARENT2_EMAIL),
      preEventContact:  g(COL.PREEVENT_CONTACT),
      preEventIntent:   g(COL.PREEVENT_INTENT),
      datePhotographed: g(COL.DATE_PHOTOGRAPHED),
      familyFilm:       g(COL.FAMILY_FILM),
      filmPeople:       n(COL.FILM_PEOPLE),
      firstSession:     g(COL.FIRST_SESSION),
      numSessions:      n(COL.NUM_SESSIONS),
      customerStatus:   g(COL.CUSTOMER_STATUS),
      internalStatus:   g(COL.INTERNAL_STATUS),
      wallArt:          g(COL.WALL_ART),
      book:             g(COL.BOOK),
      mattedPrint:      g(COL.MATTED_PRINT),
      custom:           g(COL.CUSTOM),
      totalSpend:       n(COL.TOTAL_SPEND),
      archivalPlan:     g(COL.ARCHIVAL_PLAN),
      futureOrder:      g(COL.FUTURE_ORDER),
      circleBackDate:   g(COL.CIRCLE_BACK_DATE),
      circleBackDays:   n(COL.CIRCLE_BACK_DAYS),
      testimonial:      g(COL.TESTIMONIAL),
      // Computed identity key
      athleteKey:       `${g(COL.ATHLETE_NAME)}|${g(COL.PARENT1_EMAIL)}`,
    };
  }).filter(r => r.eventName && r.athleteName);
}

function parseEvents(rows) {
  if (rows.length < 2) return [];
  return rows.slice(1).map(row => ({
    id:        (row[0] || '').trim(),
    season:    (row[1] || '').trim(),
    name:      (row[2] || '').trim(),
    date:      (row[3] || '').trim(),
    location:  (row[4] || '').trim(),
    sport:     (row[5] || '').trim(),
    athletes:  parseInt(row[6] || '0') || 0,
  })).filter(e => e.name);
}

// ─────────────────────────────────────────────
// STAGE HELPERS
// ─────────────────────────────────────────────
const isBooked   = r => r.customerStatus === 'Booked';
const isCustomer = r => ['Session Complete - Order Placed','Delivered'].includes(r.customerStatus);
const isLost     = r => ['Session Complete - Lost','Lost - Expressed Not Interested'].includes(r.customerStatus);

// ─────────────────────────────────────────────
// METRICS
// ─────────────────────────────────────────────

function calcSummary(rows) {
  const prospects = rows.length;
  const booked    = rows.filter(r => isBooked(r) || isCustomer(r)).length;
  const customers = rows.filter(r => isCustomer(r)).length;
  const totalRev  = rows.reduce((s, r) => s + r.totalSpend, 0);

  // Unique athletes by key
  const uniqueAthletes = new Set(rows.map(r => r.athleteKey)).size;

  return {
    prospects,
    booked,
    customers,
    uniqueAthletes,
    totalRevenue:   totalRev,
    aovPerCustomer: customers  > 0 ? totalRev / customers  : 0,
    aovPerBooked:   booked     > 0 ? totalRev / booked     : 0,
    aovPerProspect: prospects  > 0 ? totalRev / prospects  : 0,
  };
}

function calcFunnel(rows) {
  const prospects = rows.length;
  const booked    = rows.filter(r => isBooked(r) || isCustomer(r)).length;
  const customers = rows.filter(r => isCustomer(r)).length;
  const delivered = rows.filter(r => r.customerStatus === 'Delivered').length;
  const lost      = rows.filter(r => isLost(r)).length;

  return {
    prospects,
    booked,
    customers,
    delivered,
    lost,
    prospectToBooked:   prospects > 0 ? booked    / prospects * 100 : 0,
    bookedToCustomer:   booked    > 0 ? customers / booked    * 100 : 0,
    prospectToCustomer: prospects > 0 ? customers / prospects * 100 : 0,
  };
}

function calcAOV(rows) {
  const byStage = (filterFn) => {
    const subset  = rows.filter(filterFn);
    const total   = subset.reduce((s, r) => s + r.totalSpend, 0);
    return { count: subset.length, total, aov: subset.length > 0 ? total / subset.length : 0 };
  };
  return {
    asProspect: byStage(() => true),
    asBooked:   byStage(r => isBooked(r) || isCustomer(r)),
    asCustomer: byStage(r => isCustomer(r)),
  };
}

function calcByEvent(allRows) {
  const names = [...new Set(allRows.map(r => r.eventName).filter(Boolean))];
  return names.map(eventName => {
    const rows = allRows.filter(r => r.eventName === eventName);
    const s    = calcSummary(rows);
    return {
      eventName,
      season:   rows[0]?.season || '',
      eventDate:rows[0]?.eventDate || '',
      ...s,
      funnel: calcFunnel(rows),
    };
  }).sort((a, b) => {
    if (a.eventDate && b.eventDate) return new Date(a.eventDate) - new Date(b.eventDate);
    return a.eventName.localeCompare(b.eventName);
  });
}

function calcTrends(allRows, events) {
  return calcByEvent(allRows);
}

function calcAthleteRetention(allRows) {
  // Build a map: athleteKey → sorted list of events attended
  const athleteMap = {};
  allRows.forEach(r => {
    if (!athleteMap[r.athleteKey]) {
      athleteMap[r.athleteKey] = {
        athleteName: r.athleteName,
        email:       r.parent1Email,
        events:      [],
        totalSpend:  0,
        isCustomer:  false,
      };
    }
    athleteMap[r.athleteKey].events.push(r.eventName);
    athleteMap[r.athleteKey].totalSpend += r.totalSpend;
    if (isCustomer(r)) athleteMap[r.athleteKey].isCustomer = true;
  });

  const athletes     = Object.values(athleteMap);
  const total        = athletes.length;
  const returning    = athletes.filter(a => a.events.length > 1).length;
  const newAthletes  = total - returning;
  const repeatBuyers = athletes.filter(a => a.isCustomer && a.events.length > 1).length;

  // Top returning athletes by lifetime spend
  const topReturning = athletes
    .filter(a => a.events.length > 1)
    .sort((a, b) => b.totalSpend - a.totalSpend)
    .slice(0, 10)
    .map(a => ({
      athleteName: a.athleteName,
      eventCount:  a.events.length,
      totalSpend:  a.totalSpend,
    }));

  // Per-event: how many athletes were new vs returning
  const eventNames = [...new Set(allRows.map(r => r.eventName))];
  const seenBefore = new Set();
  const perEvent   = [];

  // Process events in chronological order
  const sortedEvents = eventNames.slice().sort((a, b) => {
    const da = allRows.find(r => r.eventName === a)?.eventDate || '';
    const db = allRows.find(r => r.eventName === b)?.eventDate || '';
    return da.localeCompare(db);
  });

  sortedEvents.forEach(eventName => {
    const eventRows    = allRows.filter(r => r.eventName === eventName);
    const newCount     = eventRows.filter(r => !seenBefore.has(r.athleteKey)).length;
    const returnCount  = eventRows.filter(r => seenBefore.has(r.athleteKey)).length;
    perEvent.push({ eventName, newAthletes: newCount, returningAthletes: returnCount, total: eventRows.length });
    eventRows.forEach(r => seenBefore.add(r.athleteKey));
  });

  return {
    totalUniqueAthletes: total,
    returning,
    newAthletes,
    returningPct:  total > 0 ? returning   / total * 100 : 0,
    newPct:        total > 0 ? newAthletes / total * 100 : 0,
    repeatBuyers,
    topReturning,
    perEvent,
  };
}

function calcSeasonTrends(allRows) {
  const seasons = [...new Set(allRows.map(r => r.season).filter(Boolean))].sort();
  return seasons.map(season => {
    const rows      = allRows.filter(r => r.season === season);
    const customers = rows.filter(r => isCustomer(r));
    const totalRev  = customers.reduce((s, r) => s + r.totalSpend, 0);
    const events    = [...new Set(rows.map(r => r.eventName))];
    return {
      season,
      events:     events.length,
      prospects:  rows.length,
      customers:  customers.length,
      totalRevenue: totalRev,
      aov:        customers.length > 0 ? totalRev / customers.length : 0,
      convRate:   rows.length > 0 ? customers.length / rows.length * 100 : 0,
    };
  });
}

function calcFilmImpact(rows) {
  const withFilm    = rows.filter(r => r.familyFilm === 'Yes');
  const withoutFilm = rows.filter(r => r.familyFilm !== 'Yes');
  const custWith    = withFilm.filter(r => isCustomer(r));
  const custWithout = withoutFilm.filter(r => isCustomer(r));
  const aov = arr => arr.length > 0 ? arr.reduce((s,r) => s+r.totalSpend, 0) / arr.length : 0;

  return {
    withFilm: {
      prospects:      withFilm.length,
      customers:      custWith.length,
      aov:            aov(custWith),
      conversionRate: withFilm.length > 0 ? custWith.length / withFilm.length * 100 : 0,
    },
    withoutFilm: {
      prospects:      withoutFilm.length,
      customers:      custWithout.length,
      aov:            aov(custWithout),
      conversionRate: withoutFilm.length > 0 ? custWithout.length / withoutFilm.length * 100 : 0,
    },
    filmLift: aov(custWith) - aov(custWithout),
  };
}

function calcPreEventImpact(rows) {
  const pre    = rows.filter(r => r.signupType === 'Pre-Event');
  const dayOf  = rows.filter(r => r.signupType !== 'Pre-Event');
  const preCust  = pre.filter(r => isCustomer(r));
  const dayCust  = dayOf.filter(r => isCustomer(r));
  const aov = arr => arr.length > 0 ? arr.reduce((s,r) => s+r.totalSpend, 0) / arr.length : 0;

  return {
    preEvent: {
      total:          pre.length,
      customers:      preCust.length,
      aov:            aov(preCust),
      conversionRate: pre.length > 0 ? preCust.length / pre.length * 100 : 0,
      contactBreakdown: {
        no:    pre.filter(r => r.preEventContact === 'No').length,
        text:  pre.filter(r => r.preEventContact === 'Text').length,
        call:  pre.filter(r => r.preEventContact === 'Call').length,
        video: pre.filter(r => r.preEventContact === 'Video').length,
      },
      intentBreakdown: {
        digital: pre.filter(r => r.preEventIntent === 'Digital').length,
        print:   pre.filter(r => r.preEventIntent === 'Print').length,
      },
    },
    dayOf: {
      total:          dayOf.length,
      customers:      dayCust.length,
      aov:            aov(dayCust),
      conversionRate: dayOf.length > 0 ? dayCust.length / dayOf.length * 100 : 0,
    },
    preEventLift: aov(preCust) - aov(dayCust),
  };
}

function calcFilmSizeImpact(rows) {
  const buckets = { '1':[], '2':[], '3':[], '4':[], '5+':[] };
  rows.filter(r => r.familyFilm === 'Yes' && isCustomer(r)).forEach(r => {
    const n   = r.filmPeople;
    if (n <= 0) return;
    const key = n >= 5 ? '5+' : String(n);
    buckets[key].push(r);
  });
  return Object.entries(buckets).map(([size, arr]) => ({
    size,
    customers:    arr.length,
    aov:          arr.length > 0 ? arr.reduce((s,r) => s+r.totalSpend, 0) / arr.length : 0,
    totalRevenue: arr.reduce((s,r) => s+r.totalSpend, 0),
  }));
}

function calcSignupTypeImpact(rows) {
  return ['Pre-Event','Clinic','Day 1','Day 2'].map(type => {
    const subset    = rows.filter(r => r.signupType === type);
    const customers = subset.filter(r => isCustomer(r));
    const aov       = customers.length > 0 ? customers.reduce((s,r) => s+r.totalSpend, 0) / customers.length : 0;
    return {
      type,
      total:          subset.length,
      customers:      customers.length,
      aov,
      conversionRate: subset.length > 0 ? customers.length / subset.length * 100 : 0,
    };
  });
}

function calcArchival(rows) {
  return ['None','1 Month','6 Months','12 Months','60 Months','120 Months'].map(plan => ({
    plan,
    count:        rows.filter(r => r.archivalPlan === plan).length,
    totalRevenue: rows.filter(r => r.archivalPlan === plan).reduce((s,r) => s+r.totalSpend, 0),
  }));
}

function calcProducts(rows) {
  const customers = rows.filter(r => isCustomer(r));
  return {
    wallArt:     customers.filter(r => r.wallArt).length,
    book:        customers.filter(r => r.book).length,
    mattedPrint: customers.filter(r => r.mattedPrint).length,
    custom:      customers.filter(r => r.custom).length,
    total:       customers.length,
  };
}

function calcCircleBack(rows) {
  const today    = new Date();
  const upcoming = rows
    .filter(r => r.circleBackDate && new Date(r.circleBackDate) >= today)
    .sort((a,b) => new Date(a.circleBackDate) - new Date(b.circleBackDate))
    .slice(0, 20)
    .map(r => ({ athleteName: r.athleteName, eventName: r.eventName, circleBackDate: r.circleBackDate, customerStatus: r.customerStatus }));

  const overdue = rows
    .filter(r => r.circleBackDate && new Date(r.circleBackDate) < today)
    .map(r => ({ athleteName: r.athleteName, eventName: r.eventName, circleBackDate: r.circleBackDate, customerStatus: r.customerStatus }));

  return { upcoming, overdue, overdueCount: overdue.length };
}