/**
 * Copyright (c) 2018 mol* contributors, licensed under MIT, See LICENSE file for more info.
 *
 * @author Alexander Rose <alexander.rose@weirdbyte.de>
 */

import { Unit, StructureProperties, StructureElement, Link } from 'mol-model/structure';

import { ColorScale, Color } from 'mol-util/color';
import { Location } from 'mol-model/location';
import { ColorThemeProps, ColorTheme, LocationColor } from '../color';

const DefaultColor = Color(0xCCCCCC)
const Description = 'Gives every chain a color based on its `asym_id` value.'

function getAsymId(unit: Unit): StructureElement.Property<string> {
    switch (unit.kind) {
        case Unit.Kind.Atomic:
            return StructureProperties.chain.label_asym_id
        case Unit.Kind.Spheres:
        case Unit.Kind.Gaussians:
            return StructureProperties.coarse.asym_id
    }
}

export function ChainIdColorTheme(props: ColorThemeProps): ColorTheme {
    let color: LocationColor
    let scale: ColorScale | undefined = undefined
    // const table: [string, Color][] = []

    if (props.structure) {
        const l = StructureElement.create()
        const { models } = props.structure
        const asymIdSerialMap = new Map<string, number>()
        let j = 0
        for (let i = 0, il = models.length; i <il; ++i) {
            models[i].properties.asymIdSerialMap.forEach((v, k) => {
                if (!asymIdSerialMap.has(k)) {
                    asymIdSerialMap.set(k, j)
                    j += 1
                }
            })
        }
        scale = ColorScale.create({ domain: [ 0, asymIdSerialMap.size - 1 ] })
        const scaleColor = scale.color

        // asymIdSerialMap.forEach((v, k) => table.push([k, scaleColor(v)]))

        color = (location: Location): Color => {
            if (StructureElement.isLocation(location)) {
                const asym_id = getAsymId(location.unit)
                return scaleColor(asymIdSerialMap.get(asym_id(location)) || 0)
            } else if (Link.isLocation(location)) {
                const asym_id = getAsymId(location.aUnit)
                l.unit = location.aUnit
                l.element = location.aUnit.elements[location.aIndex]
                return scaleColor(asymIdSerialMap.get(asym_id(l)) || 0)
            }
            return DefaultColor
        }
    } else {
        color = () => DefaultColor
    }

    return {
        granularity: 'group',
        color,
        description: Description,
        // legend: scale ? TableLegend(table) : undefined
        legend: scale ? scale.legend : undefined
    }
}