(function(angular, $, _) {
  angular.module("crmContactcats").component("crmContactCategoryFlows", {
    templateUrl: "~/crmContactcats/crmContactCategoryFlows.html",
    controller: function($scope, $timeout, crmApi4, crmStatus, $document) {
      const catHeightMin = 50, catHeightGap = 8;
      var ts = ($scope.ts = CRM.ts(null)),
        ctrl = this;

      const catDefsIndexed = {};

      // Development: set this true to use a small defined fixture instead of real data.
      const useTestFixtures = true;

      let allFlowsData;

      ctrl.redrawSankey = function() {
        let flowsData = ctrl.changesOnly
          ? allFlowsData.filter(({from_category_id, to_category_id}) => from_category_id != to_category_id)
          : allFlowsData;

        ctrl.loading = false;
        const labelWidth = ctrl.sankey.labelWidth,
          width = Math.max(600, document.querySelector('.contact-cats-sankey').clientWidth),
          snakeWidth = width - 2*labelWidth;
        ctrl.sankey.width = width;

        if (!(flowsData.length)) {
          ctrl.noStats = true;
          ctrl.stats = [];
          return;
        }
        ctrl.noStats = false;

        // Create main analysis structure, indexed by right hand side of snakes.
        // analysis = {
        //   <to-CatID>: {
        //     {
        //       cat: <the cat def object>, of the 'to' cat.
        //       sources: [
        //         {
        //            cat: <the cat def object>, of the 'from' cat.
        //            contact_count: <int>, the number of contacts moved from here.
        //         },
        //         ...
        //       ],
        //       now: <int>,      How many contacts end up in this cat.
        //       previous: <int>, How many contacts started in this cat.
        //       y: <int>,
        //     }
        //   }
        // }
        //
        // offsetWithinSourcesByCat tracks, per source, the place the
        // next snake's left-top should be, relative to the top for that category.
        const analysis = {}, analysisArray = [], offsetWithinSourcesByCat = {};
        ctrl.catDefs.forEach(cat => {
          analysis[cat.id] = { sources: [], now: 0, previous: 0, cat, y:0 };
          // This is just to make looping in order easier.
          analysisArray.push(analysis[cat.id]);
        });
        let totalContacts = 0;
        flowsData.forEach(row => {
          const {from_category_id, to_category_id, contact_count} = row;
          if (!from_category_id) {
            // from nowhere: ignore for now.
            console.log("Skipping", row);
            return; 
          }
          analysis[to_category_id].now += contact_count;
          if (!catDefsIndexed[from_category_id]) {
            console.log("from_category_id", from_category_id,  "not found in defs", catDefsIndexed);
          }
          analysis[from_category_id].previous += contact_count;
          analysis[to_category_id].sources.push({ cat: catDefsIndexed[from_category_id], contact_count });

          totalContacts += contact_count;
        });

        // Allow a cat height to grow from its min to 3x min.
        let maxCatHeight = 3 * catHeightMin;
        let maxContactsAtOneCat = Math.max(... analysisArray.map(cat => Math.max(cat.now, cat.previous)));
        let scale = maxCatHeight / maxContactsAtOneCat;
        console.log({maxCatHeight, maxContactsAtOneCat,scale});

        // Assign y-offsets for each category.
        // We start with a minimum so as to accommodate labels, but it may need to grow
        // to accommodate the total contacts in either end.
        let accumulatedY = 0;
        analysisArray.forEach(toAna => {
          toAna.y = accumulatedY;
          let thisCatHeight = Math.ceil(Math.max(catHeightMin, scale * Math.max(toAna.now, toAna.previous)));
          accumulatedY += thisCatHeight + catHeightGap;
          console.log({toCat: toAna.cat.label, toCatY: toAna.y, accumulatedY, thisCatHeight});
          // Intialise source offsets for this category.
          offsetWithinSourcesByCat[toAna.cat.id] = 0;
          // Make sure that our 'from' snake ends are ordered by category presentation_order
          // This avoids one categories snakes overlapping its others.
          toAna.sources.sort((a, b) => {
            return a.cat.presentation_order - b.cat.presentation_order;
          })
        });
        ctrl.sankey.height = Math.ceil(accumulatedY);

        // Make a list of snakes we need to draw.
        const snakes = [];
        analysisArray.forEach(toAna => {
          let offsetWithinTo = 0;
          toAna.sources.forEach(source => {
            const sourceHeight = source.contact_count * scale;
            const gradientId = 'contactcats-gradient-' + source.cat.id + '-' + toAna.cat.id;
            snakes.push({
              source,
              gradientId,
              toTop : toAna.y + offsetWithinTo,
              height : Math.max(1, Math.round(sourceHeight)),
              toCat: toAna.cat,
              fromTop: analysis[source.cat.id].y + offsetWithinSourcesByCat[source.cat.id],
              fromCat: source.cat
            });
            offsetWithinTo += sourceHeight;
            offsetWithinSourcesByCat[source.cat.id] += sourceHeight;
          });
        });

        // Create the SVG data for the snakes.
        const curve1 = snakeWidth/4, curve2 = snakeWidth*3/4;
        snakes.forEach(snake => {
          const dy = snake.fromTop - snake.toTop;
          snake.d = [
            // Move to top right of snake
            `M${snakeWidth},${snake.toTop}`,
            // Line down height of snake on right.
            `l0,${snake.height}`,
            // Curve to left bottom of snake.
            `c${-curve1},0,${-curve2},${dy},${-snakeWidth},${dy}`,
            // Up on left side
            `l0,${-snake.height}`,
            // Curve back to start.
            `c${curve1},0,${curve2},${-dy},${snakeWidth},${-dy}`,
            // Close shape.
            `z`,
          ].join(' ');
          snake.fill = `url(#${snake.gradientId})`;
        });

        ctrl.sankey.snakes = snakes;
        console.log({snakes, catDefs: catDefsIndexed, analysis});
      }

      // this.$onInit gets run after the this controller is called, and after the bindings have been applied.
      this.$onInit = async function() {
        // Default start date to 1 month ago.
        ctrl.loading = true;
        ctrl.changesOnly = false;
        ctrl.startDate = new Date();
        ctrl.startDate.setMonth(ctrl.startDate.getMonth() - 1);
        ctrl.startDate.setHours(0);
        ctrl.startDate.setMinutes(0);
        ctrl.startDate.setSeconds(0);
        if (useTestFixtures) {
          ctrl.startDate = new Date('2025-03-10');
        }
        ctrl.startDate = new Date('2025-03-10');
        ctrl.endDate = null;
        ctrl.stats = null;
        ctrl.sankey = { height: 500, width: 900, labelWidth: 150, snakeWidth: 600, snakes: [] };

        if (useTestFixtures) {
          ctrl.catDefs = [
            { id: 100, label: 'Amazing', color:'#ffcc00' },
            { id: 101, label: 'Meh', color:'#ff6f00' },
          ];
        }
        else {
          ctrl.catDefs = await crmStatus({ start: ts('Loading...'), success: ''},
            crmApi4("ContactCategoryDefinition", 'get', { orderBy: { presentation_order: 'ASC' }, withLabels: true })
          );
        }
        ctrl.loading = false;
        ctrl.catDefs.forEach(cat => {catDefsIndexed[cat.id] = cat;});

        ctrl.fetchStats = function() {
          ctrl.loading = true;
          let chain;
          if (useTestFixtures) {
            chain = Promise.resolve([
              { from_category_id: 100, to_category_id: 100, contact_count: 10 },
              { from_category_id: 100, to_category_id: 101, contact_count: 5 },
              { from_category_id: 101, to_category_id: 101, contact_count: 20 },
              { from_category_id: 101, to_category_id: 100, contact_count: 2 },
            ])
          }
          else {
            chain = crmApi4('ContactCategory', 'getFlows', {
                startDate: ctrl.startDate.toISOString().substring(0, 10),
                endDate: ctrl.endDate ? ctrl.endDate.toISOString().substring(0, 10) : '',
            })
          }
          chain.then(r => {
            allFlowsData = r;
            ctrl.redrawSankey();
          });
        }
        // do initial fetch.
        ctrl.fetchStats();
      };
    },
  });
})(angular, CRM.$, CRM._);