/**
 * Copyright (c) 2018-2019 mol* contributors, licensed under MIT, See LICENSE file for more info.
 *
 * @author Alexander Rose <alexander.rose@weirdbyte.de>
 */

import { Color } from '../../mol-util/color';
import { Location } from '../../mol-model/location';
import { StructureElement, Bond, Structure } from '../../mol-model/structure';
import { ColorTheme, LocationColor } from '../color';
import { ParamDefinition as PD } from '../../mol-util/param-definition'
import { ThemeDataContext } from '../../mol-theme/theme';
import { TableLegend, ScaleLegend } from '../../mol-util/legend';
import { getPaletteParams, getPalette } from '../../mol-util/color/palette';
import { ColorLists } from '../../mol-util/color/lists';

const DefaultList = 'dark-2'
const DefaultColor = Color(0xCCCCCC)
const Description = 'Gives every polymer chain instance a unique color based on the position (index) of the polymer in the list of polymers in the structure.'

export const PolymerIndexColorThemeParams = {
    ...getPaletteParams({ type: 'set', setList: DefaultList }),
}
export type PolymerIndexColorThemeParams = typeof PolymerIndexColorThemeParams
export function getPolymerIndexColorThemeParams(ctx: ThemeDataContext) {
    const params = PD.clone(PolymerIndexColorThemeParams)
    if (ctx.structure) {
        if (getPolymerChainCount(ctx.structure.root) > ColorLists[DefaultList].list.length) {
            params.palette.defaultValue.name = 'scale'
            params.palette.defaultValue.params = {
                ...params.palette.defaultValue.params,
                list: 'red-yellow-blue'
            }
        }
    }
    return params
}
export type PolymerIndexColorThemeProps = PD.Values<typeof PolymerIndexColorThemeParams>

function getPolymerChainCount(structure: Structure) {
    let polymerChainCount = 0
    const { units } = structure
    for (let i = 0, il = units.length; i <il; ++i) {
        if (units[i].polymerElements.length > 0) ++polymerChainCount
    }
    return polymerChainCount
}

export function PolymerIndexColorTheme(ctx: ThemeDataContext, props: PD.Values<PolymerIndexColorThemeParams>): ColorTheme<PolymerIndexColorThemeParams> {
    let color: LocationColor
    let legend: ScaleLegend | TableLegend | undefined

    if (ctx.structure) {
        const palette = getPalette(getPolymerChainCount(ctx.structure.root), props)
        legend = palette.legend

        const { units } = ctx.structure.root
        const unitIdColor = new Map<number, Color>()
        for (let i = 0, j = 0, il = units.length; i <il; ++i) {
            if (units[i].polymerElements.length > 0) {
                unitIdColor.set(units[i].id, palette.color(j))
                ++j
            }
        }

        color = (location: Location): Color => {
            let color: Color | undefined
            if (StructureElement.Location.is(location)) {
                color = unitIdColor.get(location.unit.id)
            } else if (Bond.isLocation(location)) {
                color = unitIdColor.get(location.aUnit.id)
            }
            return color !== undefined ? color : DefaultColor
        }
    } else {
        color = () => DefaultColor
    }

    return {
        factory: PolymerIndexColorTheme,
        granularity: 'instance',
        color,
        props,
        description: Description,
        legend
    }
}

export const PolymerIndexColorThemeProvider: ColorTheme.Provider<PolymerIndexColorThemeParams> = {
    label: 'Polymer Chain Instance',
    category: ColorTheme.Category.Chain,
    factory: PolymerIndexColorTheme,
    getParams: getPolymerIndexColorThemeParams,
    defaultValues: PD.getDefaultValues(PolymerIndexColorThemeParams),
    isApplicable: (ctx: ThemeDataContext) => !!ctx.structure
}