// Copyright (c) Microsoft Corporation.
// Licensed under the MIT License.

import { ChartTemplateDef } from '../../core/types';

export const candlestickChartDef: ChartTemplateDef = {
    chart: "Candlestick Chart",
    template: {
        encoding: {},
        layer: [
            { mark: "rule", encoding: {} },
            { mark: { type: "bar", size: 14 }, encoding: {} },
        ],
    },
    channels: ["x", "open", "high", "low", "close", "column", "row"],
    markCognitiveChannel: 'position',
    declareLayoutMode: () => ({
        axisFlags: { x: { banded: true } },
    }),
    instantiate: (spec, ctx) => {
        const { x, open, high, low, close, column, row } = ctx.resolvedEncodings;

        if (!spec.encoding) spec.encoding = {};
        if (x) {
            spec.encoding.x = x;
            if (x.type === 'nominal' || x.type === 'ordinal') {
                spec.encoding.x.sort = null;
            }
        }
        if (column) spec.encoding.column = column;
        if (row) spec.encoding.row = row;

        spec.encoding.y = {
            type: "quantitative",
            scale: { zero: false },
            axis: { title: null },
        };

        spec.title = { text: "Price", anchor: "start", fontSize: 11, fontWeight: "normal", color: "#666" };

        if (low) spec.layer[0].encoding.y = { field: low.field };
        if (high) spec.layer[0].encoding.y2 = { field: high.field };
        if (open) spec.layer[1].encoding.y = { field: open.field };
        if (close) spec.layer[1].encoding.y2 = { field: close.field };

        if (open?.field && close?.field) {
            spec.encoding.color = {
                condition: {
                    test: `datum['${open.field}'] < datum['${close.field}']`,
                    value: "#06982d",
                },
                value: "#ae1325",
            };
        }

        // Compute bar width from x-axis cardinality
        const table = ctx.table;
        const plotWidth = ctx.canvasSize?.width || 400;
        const xField = spec.encoding?.x?.field;
        let barSize: number;

        if (xField && table?.length > 0) {
            const cardinality = new Set(table.map((r: any) => r[xField])).size;
            barSize = Math.max(2, Math.min(20, Math.round(plotWidth * 0.6 / cardinality)));
        } else {
            barSize = 14;
        }

        spec.layer[1].mark = { ...spec.layer[1].mark, size: barSize };
    },
};