import * as math from 'mathjs';
import { Phase, type Stat, type Surface } from "./race";

export interface Race {
    location: RaceLocation;
    length: number;
    surface: Surface;
    direction: Direction;
    spans: Span[];
    slopes: Slope[];
    thresholds: [] | [Stat] | [Stat, Stat];
}

export enum RaceLocation {
    Sapporo = 'Sapporo',
    Hakodate = 'Hakodate',
    Niigata = 'Niigata',
    Fukushima = 'Fukushima',
    Nakayama = 'Nakayama',
    Tokyo = 'Tokyo',
    Chukyo = 'Chukyo',
    Kyoto = 'Kyoto',
    Hanshin = 'Hanshin',
    Kokura = 'Kokura',
    Ooi = 'Ooi',
    Kawasaki = 'Kawasaki',
    Funabashi = 'Funabashi',
    Morioka = 'Morioka',
    Longchamp = 'Longchamp',
    SantaAnitaPark = 'Santa Anita Park',
    DelMar = 'Del Mar',
}

export enum Direction {
    Right,
    Left,
    Stretch,
}

export enum SpanType {
    FrontStraight,
    AcrossStraight,
    FalseStraight,
    Corner1,
    Corner2,
    Corner3,
    Corner4,
}

export interface Span {
    type: SpanType;
    span: [number, number];
}

export interface Slope {
    per: -2 | -1.5 | -1 | 1 | 1.5 | 2;
    span: [number, number];
}

function sortSlopes(slopes: Slope[]): Slope[] {
    return slopes.toSorted((a, b) => a.span[0] - b.span[0]);
}

/**
 * Get the distances into a race where each phase ends.
 * @param raceLen Length of the race in meters
 * @returns Quadruple of phase end points, including separate late and last spurt phases
 */
export function phases(raceLen: number): [number, number, number, number] {
    const sixth = raceLen / 6;
    const half = raceLen / 2;
    return [sixth, sixth + half, 2*sixth + half, raceLen];
}

export interface SectionInfo {
    section: number;
    phase: Phase;
    endRate: number;
    posKeep: boolean;
    rush: boolean;
    spotStruggleEnter: boolean;
}

export const SECTIONS: ReadonlyArray<SectionInfo> = [
    {section: 1, phase: Phase.EarlyRace, endRate: 1/24, posKeep: true, rush: false, spotStruggleEnter: false},
    {section: 2, phase: Phase.EarlyRace, endRate: 2/24, posKeep: true, rush: true, spotStruggleEnter: true},
    {section: 3, phase: Phase.EarlyRace, endRate: 3/24, posKeep: true, rush: true, spotStruggleEnter: true},
    {section: 4, phase: Phase.EarlyRace, endRate: 4/24, posKeep: true, rush: true, spotStruggleEnter: true},
    {section: 5, phase: Phase.MidRace, endRate: 5/24, posKeep: true, rush: true, spotStruggleEnter: true},
    {section: 6, phase: Phase.MidRace, endRate: 6/24, posKeep: true, rush: true, spotStruggleEnter: false},
    {section: 7, phase: Phase.MidRace, endRate: 7/24, posKeep: true, rush: true, spotStruggleEnter: false},
    {section: 8, phase: Phase.MidRace, endRate: 8/24, posKeep: true, rush: true, spotStruggleEnter: false},
    {section: 9, phase: Phase.MidRace, endRate: 9/24, posKeep: true, rush: true, spotStruggleEnter: false},
    {section: 10, phase: Phase.MidRace, endRate: 10/24, posKeep: true, rush: false, spotStruggleEnter: false},
    {section: 11, phase: Phase.MidRace, endRate: 11/24, posKeep: false, rush: false, spotStruggleEnter: false},
    {section: 12, phase: Phase.MidRace, endRate: 12/24, posKeep: false, rush: false, spotStruggleEnter: false},
    {section: 13, phase: Phase.MidRace, endRate: 13/24, posKeep: false, rush: false, spotStruggleEnter: false},
    {section: 14, phase: Phase.MidRace, endRate: 14/24, posKeep: false, rush: false, spotStruggleEnter: false},
    {section: 15, phase: Phase.MidRace, endRate: 15/24, posKeep: false, rush: false, spotStruggleEnter: false},
    {section: 16, phase: Phase.MidRace, endRate: 16/24, posKeep: false, rush: false, spotStruggleEnter: false},
    {section: 17, phase: Phase.LateRace, endRate: 17/24, posKeep: false, rush: false, spotStruggleEnter: false},
    {section: 18, phase: Phase.LateRace, endRate: 18/24, posKeep: false, rush: false, spotStruggleEnter: false},
    {section: 19, phase: Phase.LateRace, endRate: 19/24, posKeep: false, rush: false, spotStruggleEnter: false},
    {section: 20, phase: Phase.LateRace, endRate: 20/24, posKeep: false, rush: false, spotStruggleEnter: false},
    {section: 21, phase: Phase.LateRace, endRate: 21/24, posKeep: false, rush: false, spotStruggleEnter: false},
    {section: 22, phase: Phase.LateRace, endRate: 22/24, posKeep: false, rush: false, spotStruggleEnter: false},
    {section: 23, phase: Phase.LateRace, endRate: 23/24, posKeep: false, rush: false, spotStruggleEnter: false},
    {section: 24, phase: Phase.LateRace, endRate: 24/24, posKeep: false, rush: false, spotStruggleEnter: false},
];

export interface SectionSlopeSegment extends SectionInfo {
    startDist: number;
    endDist: number;
    slope: -2 | -1.5 | -1 | 0 | 1 | 1.5 | 2;
}

export function splitSectionSlopes(raceLen: number, slopes: Slope[]): SectionSlopeSegment[] {
    const ss = sortSlopes(slopes);
    return SECTIONS.flatMap<SectionSlopeSegment>((sec) => {
        const startDist = (sec.section - 1) * raceLen / 24;
        const endDist = sec.section * raceLen / 24;
        const s = ss.filter((sl) => sl.span[0] < endDist && sl.span[1] > startDist);
        if (s.length === 0) {
            return [{...sec, startDist, endDist, slope: 0}];
        }
        const r: Array<SectionSlopeSegment> = [{...sec, startDist, endDist: math.min(s[0].span[0], endDist), slope: 0}];
        for (const [i, sl] of s.entries()) {
            const slopeEnd = math.min(endDist, sl.span[1]);
            r.push(
                {...sec, startDist: math.max(startDist, sl.span[0]), endDist: slopeEnd, slope: sl.per},
                {...sec, startDist: slopeEnd, endDist: math.min(s[i+1]?.span[0] ?? endDist, endDist), slope: 0},
            );
        }
        return r.filter((sl) => sl.startDist < sl.endDist);
    })
}