// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
import { ALL } from "./constants.ts";
import type { SemVerRange } from "./types.ts";
import { CARET, HYPHENRANGE, re, STAR, TILDE, XRANGE } from "./_shared.ts";
import { parseComparator } from "./parse_comparator.ts";

// ~, ~> --> * (any, kinda silly)
// ~2, ~2.x, ~2.x.x, ~>2, ~>2.x ~>2.x.x --> >=2.0.0 <3.0.0
// ~2.0, ~2.0.x, ~>2.0, ~>2.0.x --> >=2.0.0 <2.1.0
// ~1.2, ~1.2.x, ~>1.2, ~>1.2.x --> >=1.2.0 <1.3.0
// ~1.2.3, ~>1.2.3 --> >=1.2.3 <1.3.0
// ~1.2.0, ~>1.2.0 --> >=1.2.0 <1.3.0
function replaceTildes(comp: string): string {
  return comp
    .trim()
    .split(/\s+/)
    .map((comp) => replaceTilde(comp))
    .join(" ");
}

function replaceTilde(comp: string): string {
  const r: RegExp = re[TILDE];
  return comp.replace(
    r,
    (_: string, M: string, m: string, p: string, pr: string) => {
      let ret: string;

      if (isX(M)) {
        ret = "";
      } else if (isX(m)) {
        ret = ">=" + M + ".0.0 <" + (+M + 1) + ".0.0";
      } else if (isX(p)) {
        // ~1.2 == >=1.2.0 <1.3.0
        ret = ">=" + M + "." + m + ".0 <" + M + "." + (+m + 1) + ".0";
      } else if (pr) {
        ret = ">=" +
          M +
          "." +
          m +
          "." +
          p +
          "-" +
          pr +
          " <" +
          M +
          "." +
          (+m + 1) +
          ".0";
      } else {
        // ~1.2.3 == >=1.2.3 <1.3.0
        ret = ">=" + M + "." + m + "." + p + " <" + M + "." + (+m + 1) + ".0";
      }

      return ret;
    },
  );
}

// ^ --> * (any, kinda silly)
// ^2, ^2.x, ^2.x.x --> >=2.0.0 <3.0.0
// ^2.0, ^2.0.x --> >=2.0.0 <3.0.0
// ^1.2, ^1.2.x --> >=1.2.0 <2.0.0
// ^1.2.3 --> >=1.2.3 <2.0.0
// ^1.2.0 --> >=1.2.0 <2.0.0
function replaceCarets(comp: string): string {
  return comp
    .trim()
    .split(/\s+/)
    .map((comp) => replaceCaret(comp))
    .join(" ");
}

function replaceCaret(comp: string): string {
  const r: RegExp = re[CARET];
  return comp.replace(r, (_: string, M, m, p, pr) => {
    let ret: string;

    if (isX(M)) {
      ret = "";
    } else if (isX(m)) {
      ret = ">=" + M + ".0.0 <" + (+M + 1) + ".0.0";
    } else if (isX(p)) {
      if (M === "0") {
        ret = ">=" + M + "." + m + ".0 <" + M + "." + (+m + 1) + ".0";
      } else {
        ret = ">=" + M + "." + m + ".0 <" + (+M + 1) + ".0.0";
      }
    } else if (pr) {
      if (M === "0") {
        if (m === "0") {
          ret = ">=" +
            M +
            "." +
            m +
            "." +
            p +
            "-" +
            pr +
            " <" +
            M +
            "." +
            m +
            "." +
            (+p + 1);
        } else {
          ret = ">=" +
            M +
            "." +
            m +
            "." +
            p +
            "-" +
            pr +
            " <" +
            M +
            "." +
            (+m + 1) +
            ".0";
        }
      } else {
        ret = ">=" + M + "." + m + "." + p + "-" + pr + " <" + (+M + 1) +
          ".0.0";
      }
    } else {
      if (M === "0") {
        if (m === "0") {
          ret = ">=" + M + "." + m + "." + p + " <" + M + "." + m + "." +
            (+p + 1);
        } else {
          ret = ">=" + M + "." + m + "." + p + " <" + M + "." + (+m + 1) + ".0";
        }
      } else {
        ret = ">=" + M + "." + m + "." + p + " <" + (+M + 1) + ".0.0";
      }
    }

    return ret;
  });
}

function replaceXRanges(comp: string): string {
  return comp
    .split(/\s+/)
    .map((comp) => replaceXRange(comp))
    .join(" ");
}

function replaceXRange(comp: string): string {
  comp = comp.trim();
  const r: RegExp = re[XRANGE];
  return comp.replace(r, (ret: string, gtlt, M, m, p, _pr) => {
    const xM: boolean = isX(M);
    const xm: boolean = xM || isX(m);
    const xp: boolean = xm || isX(p);
    const anyX: boolean = xp;

    if (gtlt === "=" && anyX) {
      gtlt = "";
    }

    if (xM) {
      if (gtlt === ">" || gtlt === "<") {
        // nothing is allowed
        ret = "<0.0.0";
      } else {
        // nothing is forbidden
        ret = "*";
      }
    } else if (gtlt && anyX) {
      // we know patch is an x, because we have any x at all.
      // replace X with 0
      if (xm) {
        m = 0;
      }
      p = 0;

      if (gtlt === ">") {
        // >1 => >=2.0.0
        // >1.2 => >=1.3.0
        // >1.2.3 => >= 1.2.4
        gtlt = ">=";
        if (xm) {
          M = +M + 1;
          m = 0;
          p = 0;
        } else {
          m = +m + 1;
          p = 0;
        }
      } else if (gtlt === "<=") {
        // <=0.7.x is actually <0.8.0, since any 0.7.x should
        // pass.  Similarly, <=7.x is actually <8.0.0, etc.
        gtlt = "<";
        if (xm) {
          M = +M + 1;
        } else {
          m = +m + 1;
        }
      }

      ret = gtlt + M + "." + m + "." + p;
    } else if (xm) {
      ret = ">=" + M + ".0.0 <" + (+M + 1) + ".0.0";
    } else if (xp) {
      ret = ">=" + M + "." + m + ".0 <" + M + "." + (+m + 1) + ".0";
    }

    return ret;
  });
}

// Because * is AND-ed with everything else in the comparator,
// and '' means "any version", just remove the *s entirely.
function replaceStars(comp: string): string {
  return comp.trim().replace(re[STAR], "");
}

// This function is passed to string.replace(re[HYPHENRANGE])
// M, m, patch, prerelease, build
// 1.2 - 3.4.5 -> >=1.2.0 <=3.4.5
// 1.2.3 - 3.4 -> >=1.2.0 <3.5.0 Any 3.4.x will do
// 1.2 - 3.4 -> >=1.2.0 <3.5.0
function hyphenReplace(
  _$0: string,
  from: string,
  fM: string,
  fm: string,
  fp: string,
  _fpr: string,
  _fb: string,
  to: string,
  tM: string,
  tm: string,
  tp: string,
  tpr: string,
  _tb: string,
) {
  if (isX(fM)) {
    from = "";
  } else if (isX(fm)) {
    from = ">=" + fM + ".0.0";
  } else if (isX(fp)) {
    from = ">=" + fM + "." + fm + ".0";
  } else {
    from = ">=" + from;
  }

  if (isX(tM)) {
    to = "";
  } else if (isX(tm)) {
    to = "<" + (+tM + 1) + ".0.0";
  } else if (isX(tp)) {
    to = "<" + tM + "." + (+tm + 1) + ".0";
  } else if (tpr) {
    to = "<=" + tM + "." + tm + "." + tp + "-" + tpr;
  } else {
    to = "<=" + to;
  }

  return (from + " " + to).trim();
}

function isX(id: string): boolean {
  return !id || id.toLowerCase() === "x" || id === "*";
}

/**
 * Parses a range string into a SemVerRange object or throws a TypeError.
 * @param range The range string
 * @returns A valid semantic version range
 */
export function parseRange(range: string): SemVerRange {
  // handle spaces around and between comparator and version
  range = range.trim().replaceAll(/(?<=<|>|=) /g, "");

  if (range === "") {
    return { ranges: [[ALL]] };
  }

  // Split into groups of comparators, these are considered OR'd together.
  const ranges = range
    .trim()
    .split(/\s*\|\|\s*/)
    .map((range) => {
      // convert `1.2.3 - 1.2.4` into `>=1.2.3 <=1.2.4`
      const hr: RegExp = re[HYPHENRANGE];
      range = range.replace(hr, hyphenReplace);
      range = replaceCarets(range);
      range = replaceTildes(range);
      range = replaceXRanges(range);
      range = replaceStars(range);

      // At this point, the range is completely trimmed and
      // ready to be split into comparators.
      // These are considered AND's
      if (range === "") {
        return [ALL];
      } else {
        return range
          .split(" ")
          .filter((r) => r)
          .map((r) => parseComparator(r));
      }
    });

  return { ranges };
}