import { enhance } from "@zenstackhq/runtime";
import { random_rgba } from "~/utils/color";
import { volume } from "~/utils/conversions";
import timeAgo from "~/utils/datetime";
import { db } from "~/utils/db.server";
import { randomRange } from "~/utils/random";

export async function generateDrinksChartData(id: number){
    const dbe = enhance(db);

    // Get the previous month in dates
    var dates = [];
    
    const now = Date.now();
    const subtracter = (1000 * 60 * 60 * 24);

    for(let i = 0; i <= 30; i++){
      let date = now - (subtracter * i);
      dates.push(new Date(date));
    }

    dates.reverse();

    // Generate labels
    const labels = dates.map((date)=> timeAgo(date));

    // History of specific drink
    const containersWithHistory = await dbe.container.findMany({
      where: {drink_id: id},
      include: {checkouts: {orderBy: {checkoutAt: "asc"}, where: {checkoutAt: {gte: dates[0]}}}}
    })

    var datasets : any = [];

    for(let container of containersWithHistory){
      
      if(container.inventory == 0 && container.checkouts.length == 0) continue;

      var history = container.checkouts;
      var totalInventory = container.inventory;

      // Generate arrays of data
      var checkouts = [];
      var inventoryAfter = [];

      var lastInventoryAfter = history.length > 0 ? history[0].inventoryAfter + 1 : 0;
      var previousCheckoutInventoryAfter = history.length > 0 ? history[0].inventoryAfter : 0;

      var lastChange = 0;
      var previousLastChange = 0;

      for(let i = 0; i <= dates.length - 1; i++){
        let startDate = dates[i];
        let endDate = dates[i+1];

        let totalCheckouts = 0;

        for(let entry of history){
          if(entry.checkoutAt > startDate && entry.checkoutAt < endDate){
            totalCheckouts++;
            lastInventoryAfter = entry.inventoryAfter;
            lastChange = i;
          }
        }

        // There was inventory added
        if((lastInventoryAfter + totalCheckouts) > previousCheckoutInventoryAfter){
          if(i > 0 && checkouts[i-1] > 0){
            // Special case, there were also checkouts the previous day, do nothing
          } else if(i > 0) {
            let index = randomRange(previousLastChange + 1, i - 1);
            for(let j = index; j <= i - 1; j++){
              inventoryAfter[j] = lastInventoryAfter + totalCheckouts;
            }
          }
        }
        previousCheckoutInventoryAfter = lastInventoryAfter;
        previousLastChange = lastChange;

        checkouts[i] = totalCheckouts;
        inventoryAfter[i] = lastInventoryAfter;
      }

      // Force the remaining inventory left values after the last checkout to be equal to 
      // the actual remaining inventory
      let index = randomRange(lastChange + 1, dates.length - 1);
      for(let i = index; i <= dates.length - 1; i++){
        inventoryAfter[i] = totalInventory;
      }

      let [color1, color2] = random_rgba(2);

      datasets.push({
        type: "line",
        label: 'Inventory ' + volume(container.volume),
        data: inventoryAfter,
        borderColor: color1,
        backgroundColor: color1,
        tension: 0.1
      });
      datasets.push({
          type: 'bar',
          label: 'Checkouts ' + volume(container.volume),
          data: checkouts,
          borderColor: color2,
          backgroundColor: color2,
      });
    }

    const data = {
      labels,
      datasets: datasets
    };
  
    return data;
  }