/**
 * Copyright (c) 2019-2020 mol* contributors, licensed under MIT, See LICENSE file for more info.
 *
 * @author Alexander Rose <alexander.rose@weirdbyte.de>
 */

import { ParamDefinition as PD } from '../../../mol-util/param-definition';
import { Structure, Unit } from '../../../mol-model/structure';
import { Features, FeaturesBuilder } from './features';
import { ValenceModelProvider } from '../valence-model';
import { InteractionsIntraContacts, InteractionsInterContacts, FeatureType, interactionTypeLabel } from './common';
import { IntraContactsBuilder, InterContactsBuilder } from './contacts-builder';
import { IntMap } from '../../../mol-data/int';
import { addUnitContacts, ContactTester, addStructureContacts, ContactProvider, ContactsParams, ContactsProps } from './contacts';
import { HalogenDonorProvider, HalogenAcceptorProvider, HalogenBondsProvider } from './halogen-bonds';
import { HydrogenDonorProvider, WeakHydrogenDonorProvider, HydrogenAcceptorProvider, HydrogenBondsProvider, WeakHydrogenBondsProvider } from './hydrogen-bonds';
import { NegativChargeProvider, PositiveChargeProvider, AromaticRingProvider, IonicProvider, PiStackingProvider, CationPiProvider } from './charged';
import { HydrophobicAtomProvider, HydrophobicProvider } from './hydrophobic';
import { SetUtils } from '../../../mol-util/set';
import { MetalCoordinationProvider, MetalProvider, MetalBindingProvider } from './metal';
import { refineInteractions } from './refine';
import { CustomProperty } from '../../common/custom-property';
import { DataLocation } from '../../../mol-model/location';
import { CentroidHelper } from '../../../mol-math/geometry/centroid-helper';
import { Sphere3D } from '../../../mol-math/geometry';
import { DataLoci } from '../../../mol-model/loci';

export { Interactions }

interface Interactions {
    /** Features of each unit */
    unitsFeatures: IntMap<Features>
    /** Interactions of each unit */
    unitsContacts: IntMap<InteractionsIntraContacts>
    /** Interactions between units */
    contacts: InteractionsInterContacts
}

namespace Interactions {
    export interface Element {
        unitA: Unit
        /** Index into features of unitA */
        indexA: Features.FeatureIndex
        unitB: Unit
        /** Index into features of unitB */
        indexB: Features.FeatureIndex
    }
    export interface Location extends DataLocation<Interactions, Element> {}

    export function Location(interactions: Interactions, unitA?: Unit, indexA?: Features.FeatureIndex, unitB?: Unit, indexB?: Features.FeatureIndex): Location {
        return DataLocation('interactions', interactions, { unitA: unitA as any, indexA: indexA as any, unitB: unitB as any, indexB: indexB as any });
    }

    export function isLocation(x: any): x is Location {
        return !!x && x.kind === 'data-location' && x.tag === 'interactions';
    }

    export function areLocationsEqual(locA: Location, locB: Location) {
        return (
            locA.data === locB.data &&
            locA.element.indexA === locB.element.indexA &&
            locA.element.indexB === locB.element.indexB &&
            locA.element.unitA === locB.element.unitA &&
            locA.element.unitB === locB.element.unitB
        )
    }

    function _label(interactions: Interactions, element: Element): string {
        const { unitA, indexA, unitB, indexB } = element
        const { contacts, unitsContacts } = interactions
        if (unitA === unitB) {
            const contacts = unitsContacts.get(unitA.id)
            const idx = contacts.getDirectedEdgeIndex(indexA, indexB)
            return interactionTypeLabel(contacts.edgeProps.type[idx])
        } else {
            const idx = contacts.getEdgeIndex(indexA, unitA, indexB, unitB)
            return interactionTypeLabel(contacts.edges[idx].props.type)
        }
    }

    export function locationLabel(location: Location): string {
        return _label(location.data, location.element)
    }

    type StructureInteractions = { readonly structure: Structure, readonly interactions: Interactions }
    export interface Loci extends DataLoci<StructureInteractions, Element> { }

    export function Loci(structure: Structure, interactions: Interactions, elements: ReadonlyArray<Element>): Loci {
        return DataLoci('interactions', { structure, interactions }, elements, (boundingSphere) => getBoundingSphere(interactions, elements, boundingSphere), () => getLabel(interactions, elements));
    }

    export function isLoci(x: any): x is Loci {
        return !!x && x.kind === 'data-loci' && x.tag === 'interactions';
    }

    export function getBoundingSphere(interactions: Interactions, elements: ReadonlyArray<Element>, boundingSphere: Sphere3D) {
        const { unitsFeatures } = interactions
        return CentroidHelper.fromPairProvider(elements.length, (i, pA, pB) => {
            const e = elements[i]
            Features.setPosition(pA, e.unitA, e.indexA, unitsFeatures.get(e.unitA.id))
            Features.setPosition(pB, e.unitB, e.indexB, unitsFeatures.get(e.unitB.id))
        }, boundingSphere)
    }

    export function getLabel(interactions: Interactions, elements: ReadonlyArray<Element>) {
        return elements.length > 0 ? _label(interactions, elements[0]) : ''
    }
}

const FeatureProviders = [
    HydrogenDonorProvider, WeakHydrogenDonorProvider, HydrogenAcceptorProvider,
    NegativChargeProvider, PositiveChargeProvider, AromaticRingProvider,
    HalogenDonorProvider, HalogenAcceptorProvider,
    HydrophobicAtomProvider,
    MetalProvider, MetalBindingProvider,
]

const ContactProviders = {
    'ionic': IonicProvider,
    'pi-stacking': PiStackingProvider,
    'cation-pi': CationPiProvider,
    'halogen-bonds': HalogenBondsProvider,
    'hydrogen-bonds': HydrogenBondsProvider,
    'weak-hydrogen-bonds': WeakHydrogenBondsProvider,
    'hydrophobic': HydrophobicProvider,
    'metal-coordination': MetalCoordinationProvider,
}
type ContactProviders = typeof ContactProviders

function getProvidersParams() {
    const params: { [k in keyof ContactProviders]: PD.Group<ContactProviders[k]['params']> } = Object.create(null)
    Object.keys(ContactProviders).forEach(k => {
        (params as any)[k] = PD.Group(ContactProviders[k as keyof ContactProviders].params)
    })
    return params
}
export const InteractionsParams = {
    types: PD.MultiSelect([
        // 'ionic',
        'cation-pi',
        'pi-stacking',
        'hydrogen-bonds',
        'halogen-bonds',
        // 'hydrophobic',
        'metal-coordination',
        // 'weak-hydrogen-bonds',
    ], PD.objectToOptions(ContactProviders)),
    contacts: PD.Group(ContactsParams, { isFlat: true }),
    ...getProvidersParams()
}
export type InteractionsParams = typeof InteractionsParams
export type InteractionsProps = PD.Values<InteractionsParams>

export async function computeInteractions(ctx: CustomProperty.Context, structure: Structure, props: Partial<InteractionsProps>): Promise<Interactions> {
    const p = { ...PD.getDefaultValues(InteractionsParams), ...props }
    await ValenceModelProvider.attach(ctx, structure)

    const contactProviders: ContactProvider<any>[] = []
    Object.keys(ContactProviders).forEach(k => {
        if (p.types.includes(k)) contactProviders.push(ContactProviders[k as keyof typeof ContactProviders])
    })
    const contactTesters = contactProviders.map(l => l.createTester(p[l.name as keyof InteractionsProps]))

    const requiredFeatures = new Set<FeatureType>()
    contactTesters.forEach(l => SetUtils.add(requiredFeatures, l.requiredFeatures))
    const featureProviders = FeatureProviders.filter(f => SetUtils.areIntersecting(requiredFeatures, f.types))

    const unitsFeatures = IntMap.Mutable<Features>()
    const unitsContacts = IntMap.Mutable<InteractionsIntraContacts>()

    for (let i = 0, il = structure.unitSymmetryGroups.length; i < il; ++i) {
        const group = structure.unitSymmetryGroups[i]
        if (ctx.runtime.shouldUpdate) {
            await ctx.runtime.update({ message: 'computing interactions', current: i, max: il })
        }
        const features = findUnitFeatures(structure, group.units[0], featureProviders)
        const intraUnitContacts = findIntraUnitContacts(structure, group.units[0], features, contactTesters, p.contacts)
        for (let j = 0, jl = group.units.length; j < jl; ++j) {
            const u = group.units[j]
            unitsFeatures.set(u.id, features)
            unitsContacts.set(u.id, intraUnitContacts)
        }
    }

    const contacts = findInterUnitContacts(structure, unitsFeatures, contactTesters, p.contacts)

    const interactions = { unitsFeatures, unitsContacts, contacts }
    refineInteractions(structure, interactions)
    return interactions
}

function findUnitFeatures(structure: Structure, unit: Unit, featureProviders: Features.Provider[]) {
    const count = unit.elements.length
    const featuresBuilder = FeaturesBuilder.create(count, count / 2)
    if (Unit.isAtomic(unit)) {
        for (const fp of featureProviders) {
            fp.add(structure, unit, featuresBuilder)
        }
    }
    return featuresBuilder.getFeatures(count)
}

function findIntraUnitContacts(structure: Structure, unit: Unit, features: Features, contactTesters: ReadonlyArray<ContactTester>, props: ContactsProps) {
    const builder = IntraContactsBuilder.create(features, unit.elements.length)
    if (Unit.isAtomic(unit)) {
        addUnitContacts(structure, unit, features, builder, contactTesters, props)
    }
    return builder.getContacts()
}

function findInterUnitContacts(structure: Structure, unitsFeatures: IntMap<Features>, contactTesters: ReadonlyArray<ContactTester>, props: ContactsProps) {
    const builder = InterContactsBuilder.create()

    Structure.eachUnitPair(structure, (unitA: Unit, unitB: Unit) => {
        const featuresA = unitsFeatures.get(unitA.id)
        const featuresB = unitsFeatures.get(unitB.id)
        addStructureContacts(structure, unitA as Unit.Atomic, featuresA, unitB as Unit.Atomic, featuresB, builder, contactTesters, props)
    }, {
        maxRadius: Math.max(...contactTesters.map(t => t.maxDistance)),
        validUnit: (unit: Unit) => Unit.isAtomic(unit),
        validUnitPair: (unitA: Unit, unitB: Unit) => Structure.validUnitPair(structure, unitA, unitB)
    })

    return builder.getContacts(unitsFeatures)
}