'use strict';

const chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ_$";
const unsafeChars = /[<>\b\f\n\r\t\0\u2028\u2029]/g;
const reserved = /^(?:do|if|in|for|int|let|new|try|var|byte|case|char|else|enum|goto|long|this|void|with|await|break|catch|class|const|final|float|short|super|throw|while|yield|delete|double|export|import|native|return|switch|throws|typeof|boolean|default|extends|finally|package|private|abstract|continue|debugger|function|volatile|interface|protected|transient|implements|instanceof|synchronized)$/;
const escaped = {
  "<": "\\u003C",
  ">": "\\u003E",
  "/": "\\u002F",
  "\\": "\\\\",
  "\b": "\\b",
  "\f": "\\f",
  "\n": "\\n",
  "\r": "\\r",
  "	": "\\t",
  "\0": "\\0",
  "\u2028": "\\u2028",
  "\u2029": "\\u2029"
};
const objectProtoOwnPropertyNames = Object.getOwnPropertyNames(Object.prototype).sort().join("\0");
function devalue(value) {
  const counts = new Map();
  let logNum = 0;
  function log(message) {
    if (logNum < 100) {
      console.warn(message);
      logNum += 1;
    }
  }
  function walk(thing) {
    if (typeof thing === "function") {
      log(`Cannot stringify a function ${thing.name}`);
      return;
    }
    if (counts.has(thing)) {
      counts.set(thing, counts.get(thing) + 1);
      return;
    }
    counts.set(thing, 1);
    if (!isPrimitive(thing)) {
      const type = getType(thing);
      switch (type) {
        case "Number":
        case "String":
        case "Boolean":
        case "Date":
        case "RegExp":
          return;
        case "Array":
          thing.forEach(walk);
          break;
        case "Set":
        case "Map":
          Array.from(thing).forEach(walk);
          break;
        default:
          const proto = Object.getPrototypeOf(thing);
          if (proto !== Object.prototype && proto !== null && Object.getOwnPropertyNames(proto).sort().join("\0") !== objectProtoOwnPropertyNames) {
            if (typeof thing.toJSON !== "function") {
              log(`Cannot stringify arbitrary non-POJOs ${thing.constructor.name}`);
            }
          } else if (Object.getOwnPropertySymbols(thing).length > 0) {
            log(`Cannot stringify POJOs with symbolic keys ${Object.getOwnPropertySymbols(thing).map((symbol) => symbol.toString())}`);
          } else {
            Object.keys(thing).forEach((key) => walk(thing[key]));
          }
      }
    }
  }
  walk(value);
  const names = new Map();
  Array.from(counts).filter((entry) => entry[1] > 1).sort((a, b) => b[1] - a[1]).forEach((entry, i) => {
    names.set(entry[0], getName(i));
  });
  function stringify(thing) {
    if (names.has(thing)) {
      return names.get(thing);
    }
    if (isPrimitive(thing)) {
      return stringifyPrimitive(thing);
    }
    const type = getType(thing);
    switch (type) {
      case "Number":
      case "String":
      case "Boolean":
        return `Object(${stringify(thing.valueOf())})`;
      case "RegExp":
        return thing.toString();
      case "Date":
        return `new Date(${thing.getTime()})`;
      case "Array":
        const members = thing.map((v, i) => i in thing ? stringify(v) : "");
        const tail = thing.length === 0 || thing.length - 1 in thing ? "" : ",";
        return `[${members.join(",")}${tail}]`;
      case "Set":
      case "Map":
        return `new ${type}([${Array.from(thing).map(stringify).join(",")}])`;
      default:
        if (thing.toJSON) {
          let json = thing.toJSON();
          if (getType(json) === "String") {
            try {
              json = JSON.parse(json);
            } catch (e) {
            }
          }
          return stringify(json);
        }
        if (Object.getPrototypeOf(thing) === null) {
          if (Object.keys(thing).length === 0) {
            return "Object.create(null)";
          }
          return `Object.create(null,{${Object.keys(thing).map((key) => `${safeKey(key)}:{writable:true,enumerable:true,value:${stringify(thing[key])}}`).join(",")}})`;
        }
        return `{${Object.keys(thing).map((key) => `${safeKey(key)}:${stringify(thing[key])}`).join(",")}}`;
    }
  }
  const str = stringify(value);
  if (names.size) {
    const params = [];
    const statements = [];
    const values = [];
    names.forEach((name, thing) => {
      params.push(name);
      if (isPrimitive(thing)) {
        values.push(stringifyPrimitive(thing));
        return;
      }
      const type = getType(thing);
      switch (type) {
        case "Number":
        case "String":
        case "Boolean":
          values.push(`Object(${stringify(thing.valueOf())})`);
          break;
        case "RegExp":
          values.push(thing.toString());
          break;
        case "Date":
          values.push(`new Date(${thing.getTime()})`);
          break;
        case "Array":
          values.push(`Array(${thing.length})`);
          thing.forEach((v, i) => {
            statements.push(`${name}[${i}]=${stringify(v)}`);
          });
          break;
        case "Set":
          values.push("new Set");
          statements.push(`${name}.${Array.from(thing).map((v) => `add(${stringify(v)})`).join(".")}`);
          break;
        case "Map":
          values.push("new Map");
          statements.push(`${name}.${Array.from(thing).map(([k, v]) => `set(${stringify(k)}, ${stringify(v)})`).join(".")}`);
          break;
        default:
          values.push(Object.getPrototypeOf(thing) === null ? "Object.create(null)" : "{}");
          Object.keys(thing).forEach((key) => {
            statements.push(`${name}${safeProp(key)}=${stringify(thing[key])}`);
          });
      }
    });
    statements.push(`return ${str}`);
    return `(function(${params.join(",")}){${statements.join(";")}}(${values.join(",")}))`;
  } else {
    return str;
  }
}
function getName(num) {
  let name = "";
  do {
    name = chars[num % chars.length] + name;
    num = ~~(num / chars.length) - 1;
  } while (num >= 0);
  return reserved.test(name) ? `${name}0` : name;
}
function isPrimitive(thing) {
  return Object(thing) !== thing;
}
function stringifyPrimitive(thing) {
  if (typeof thing === "string") {
    return stringifyString(thing);
  }
  if (thing === void 0) {
    return "void 0";
  }
  if (thing === 0 && 1 / thing < 0) {
    return "-0";
  }
  const str = String(thing);
  if (typeof thing === "number") {
    return str.replace(/^(-)?0\./, "$1.");
  }
  return str;
}
function getType(thing) {
  return Object.prototype.toString.call(thing).slice(8, -1);
}
function escapeUnsafeChar(c) {
  return escaped[c] || c;
}
function escapeUnsafeChars(str) {
  return str.replace(unsafeChars, escapeUnsafeChar);
}
function safeKey(key) {
  return /^[_$a-zA-Z][_$a-zA-Z0-9]*$/.test(key) ? key : escapeUnsafeChars(JSON.stringify(key));
}
function safeProp(key) {
  return /^[_$a-zA-Z][_$a-zA-Z0-9]*$/.test(key) ? `.${key}` : `[${escapeUnsafeChars(JSON.stringify(key))}]`;
}
function stringifyString(str) {
  let result = '"';
  for (let i = 0; i < str.length; i += 1) {
    const char = str.charAt(i);
    const code = char.charCodeAt(0);
    if (char === '"') {
      result += '\\"';
    } else if (char in escaped) {
      result += escaped[char];
    } else if (code >= 55296 && code <= 57343) {
      const next = str.charCodeAt(i + 1);
      if (code <= 56319 && (next >= 56320 && next <= 57343)) {
        result += char + str[++i];
      } else {
        result += `\\u${code.toString(16).toUpperCase()}`;
      }
    } else {
      result += char;
    }
  }
  result += '"';
  return result;
}

module.exports = devalue;
