import * as _ from 'lodash'
import type {
  exportEnv,
  exportDistribution,
} from "../rescript/ProgramEvaluator.gen";
export type {  exportEnv, exportDistribution };
import { genericDist, samplingParams, evaluate, expressionValue, errorValue, distributionError, toPointSet, continuousShape, discreteShape, distributionErrorToString } from "../rescript/TypescriptInterface.gen";
export { makeSampleSetDist, errorValueToString, distributionErrorToString } from "../rescript/TypescriptInterface.gen";
import {
  Constructors_mean,
  Constructors_sample,
  Constructors_pdf,
  Constructors_cdf,
  Constructors_inv,
  Constructors_normalize,
  Constructors_toPointSet,
  Constructors_toSampleSet,
  Constructors_truncate,
  Constructors_inspect,
  Constructors_toString,
  Constructors_toSparkline,
  Constructors_algebraicAdd,
  Constructors_algebraicMultiply,
  Constructors_algebraicDivide,
  Constructors_algebraicSubtract,
  Constructors_algebraicLogarithm,
  Constructors_algebraicPower,
  Constructors_pointwiseAdd,
  Constructors_pointwiseMultiply,
  Constructors_pointwiseDivide,
  Constructors_pointwiseSubtract,
  Constructors_pointwiseLogarithm,
  Constructors_pointwisePower,
} from "../rescript/Distributions/DistributionOperation/DistributionOperation.gen";
export type {samplingParams, errorValue}

export let defaultSamplingInputs: samplingParams = {
  sampleCount: 10000,
  xyPointLength: 10000
};

export type result<a, b> =
  | {
      tag: "Ok";
      value: a;
    }
  | {
      tag: "Error";
      value: b;
    };

export function resultMap<a, b, c>(
  r: result<a, c>,
  mapFn: (x: a) => b
): result<b, c> {
  if (r.tag === "Ok") {
    return { tag: "Ok", value: mapFn(r.value) };
  } else {
    return r;
  }
}

function Ok<a,b>(x: a): result<a,b> {
  return {"tag": "Ok", value: x}
}

type tagged<a, b> = {tag: a, value: b}

function tag<a,b>(x: a, y: b) : tagged<a, b>{
  return { tag: x, value: y}
}

export type squiggleExpression = tagged<"symbol", string> | tagged<"string", string> | tagged<"array", squiggleExpression[]> | tagged<"boolean", boolean> | tagged<"distribution", Distribution> | tagged<"number", number> | tagged<"record", {[key: string]: squiggleExpression }>
export function run(
  squiggleString: string,
  samplingInputs?: samplingParams,
  _environment?: exportEnv
): result<squiggleExpression, errorValue> {
  let si: samplingParams = samplingInputs
    ? samplingInputs
    : defaultSamplingInputs;
  let result : result<expressionValue, errorValue> = evaluate(squiggleString);
  return resultMap(result, x => createTsExport(x, si));
}


function createTsExport(x: expressionValue, sampEnv: samplingParams): squiggleExpression {
  switch (x.tag) {
    case "EvArray":
      return tag("array", x.value.map(x => createTsExport(x, sampEnv)));
    case "EvBool":
      return tag("boolean", x.value);
    case "EvDistribution":
      return tag("distribution", new Distribution(x.value, sampEnv));
    case "EvNumber":
      return tag("number", x.value);
    case "EvRecord":
      return tag("record", _.mapValues(x.value, x => createTsExport(x, sampEnv)))
  }
}


export function resultExn<a, c>(r: result<a, c>): a | c {
  return r.value;
}

export type point = { x: number, y: number}

export type shape = {
  continuous: point[]
  discrete: point[]
}

function shapePoints(x : continuousShape | discreteShape): point[]{
  let xs = x.xyShape.xs;
  let ys = x.xyShape.ys;
  return _.zipWith(xs, ys, (x, y) => ({x, y}))
}

export class Distribution {
  t: genericDist;
  env: samplingParams;

  constructor(t: genericDist, env: samplingParams) {
    this.t = t;
    this.env = env;
    return this;
  }

  mapResultDist(r: result<genericDist, distributionError>): result<Distribution, distributionError> {
    return resultMap(r, (v: genericDist) => new Distribution(v, this.env));
  }

  mean(): result<number, distributionError> {
    return Constructors_mean({ env: this.env }, this.t);
  }

  sample(): result<number, distributionError> {
    return Constructors_sample({ env: this.env }, this.t);
  }

  pdf(n: number): result<number, distributionError> {
    return Constructors_pdf({ env: this.env }, this.t, n);
  }

  cdf(n: number): result<number, distributionError> {
    return Constructors_cdf({ env: this.env }, this.t, n);
  }

  inv(n: number): result<number, distributionError> {
    return Constructors_inv({ env: this.env }, this.t, n);
  }

  normalize(): result<Distribution, distributionError> {
    return this.mapResultDist(
      Constructors_normalize({ env: this.env }, this.t)
    );
  }

  shape() : result<shape, distributionError> {
    let pointSet = toPointSet(this.t, {xyPointLength: this.env.xyPointLength, sampleCount: this.env.sampleCount}, null);
    if(pointSet.tag === "Ok"){
      let distribution = pointSet.value;
      if(distribution.tag === "Continuous"){
        return Ok({
          continuous: shapePoints(distribution.value),
          discrete: []
        })
      }
      else if(distribution.tag === "Discrete"){
        return Ok({
          discrete: shapePoints(distribution.value),
          continuous: []
        })
      }
      else if(distribution.tag === "Mixed"){
        return Ok({
          discrete: shapePoints(distribution.value.discrete),
          continuous: shapePoints(distribution.value.continuous)
        })
      }
    }
    else {
      return pointSet
    }
  }

  toPointSet(): result<Distribution, distributionError> {
    return this.mapResultDist(
      Constructors_toPointSet({ env: this.env }, this.t)
    );
  }

  toSampleSet(n: number): result<Distribution, distributionError> {
    return this.mapResultDist(
      Constructors_toSampleSet({ env: this.env }, this.t, n)
    );
  }

  truncate(left: number, right: number): result<Distribution, distributionError> {
    return this.mapResultDist(
      Constructors_truncate({ env: this.env }, this.t, left, right)
    );
  }

  inspect(): result<Distribution, distributionError> {
    return this.mapResultDist(Constructors_inspect({ env: this.env }, this.t));
  }

  toString(): string {
    let result = Constructors_toString({ env: this.env }, this.t);
    if(result.tag  === "Ok"){
      result.value
    }
    else {
      return distributionErrorToString(result.value)
    }
  }

  toSparkline(n: number): result<string, distributionError> {
    return Constructors_toSparkline({ env: this.env }, this.t, n);
  }

  algebraicAdd(d2: Distribution): result<Distribution, distributionError> {
    return this.mapResultDist(
      Constructors_algebraicAdd({ env: this.env }, this.t, d2.t)
    );
  }

  algebraicMultiply(d2: Distribution): result<Distribution, distributionError> {
    return this.mapResultDist(
      Constructors_algebraicMultiply({ env: this.env }, this.t, d2.t)
    );
  }

  algebraicDivide(d2: Distribution): result<Distribution, distributionError> {
    return this.mapResultDist(
      Constructors_algebraicDivide({ env: this.env }, this.t, d2.t)
    );
  }

  algebraicSubtract(d2: Distribution): result<Distribution, distributionError> {
    return this.mapResultDist(
      Constructors_algebraicSubtract({ env: this.env }, this.t, d2.t)
    );
  }

  algebraicLogarithm(d2: Distribution): result<Distribution, distributionError> {
    return this.mapResultDist(
      Constructors_algebraicLogarithm({ env: this.env }, this.t, d2.t)
    );
  }

  algebraicPower(d2: Distribution): result<Distribution, distributionError> {
    return this.mapResultDist(
      Constructors_algebraicPower({ env: this.env }, this.t, d2.t)
    );
  }

  pointwiseAdd(d2: Distribution): result<Distribution, distributionError> {
    return this.mapResultDist(
      Constructors_pointwiseAdd({ env: this.env }, this.t, d2.t)
    );
  }

  pointwiseMultiply(d2: Distribution): result<Distribution, distributionError> {
    return this.mapResultDist(
      Constructors_pointwiseMultiply({ env: this.env }, this.t, d2.t)
    );
  }

  pointwiseDivide(d2: Distribution): result<Distribution, distributionError> {
    return this.mapResultDist(
      Constructors_pointwiseDivide({ env: this.env }, this.t, d2.t)
    );
  }

  pointwiseSubtract(d2: Distribution): result<Distribution, distributionError> {
    return this.mapResultDist(
      Constructors_pointwiseSubtract({ env: this.env }, this.t, d2.t)
    );
  }

  pointwiseLogarithm(d2: Distribution): result<Distribution, distributionError> {
    return this.mapResultDist(
      Constructors_pointwiseLogarithm({ env: this.env }, this.t, d2.t)
    );
  }

  pointwisePower(d2: Distribution): result<Distribution, distributionError> {
    return this.mapResultDist(
      Constructors_pointwisePower({ env: this.env }, this.t, d2.t)
    );
  }
}