/**
 * @fileoverview A rule to disallow the type conversions with shorter notations.
 * @author Toru Nagashima
 */

'use strict';

const astUtils = require('./utils/ast-utils');

//------------------------------------------------------------------------------
// Helpers
//------------------------------------------------------------------------------

const INDEX_OF_PATTERN = /^(?:i|lastI)ndexOf$/u;
const ALLOWABLE_OPERATORS = ['~', '!!', '+', '- -', '-', '*'];

/**
 * Checks whether or not a node is a double logical negating.
 * @param {ASTNode} node An UnaryExpression node to check.
 * @returns {boolean} Whether or not the node is a double logical negating.
 */
function isDoubleLogicalNegating(node) {
  return (
    node.operator === '!' &&
    node.argument.type === 'UnaryExpression' &&
    node.argument.operator === '!'
  );
}

/**
 * Checks whether or not a node is a binary negating of `.indexOf()` method calling.
 * @param {ASTNode} node An UnaryExpression node to check.
 * @returns {boolean} Whether or not the node is a binary negating of `.indexOf()` method calling.
 */
function isBinaryNegatingOfIndexOf(node) {
  if (node.operator !== '~') {
    return false;
  }
  const callNode = astUtils.skipChainExpression(node.argument);

  return (
    callNode.type === 'CallExpression' &&
    astUtils.isSpecificMemberAccess(callNode.callee, null, INDEX_OF_PATTERN)
  );
}

/**
 * Checks whether or not a node is a multiplying by one.
 * @param {BinaryExpression} node A BinaryExpression node to check.
 * @returns {boolean} Whether or not the node is a multiplying by one.
 */
function isMultiplyByOne(node) {
  return (
    node.operator === '*' &&
    ((node.left.type === 'Literal' && node.left.value === 1) ||
      (node.right.type === 'Literal' && node.right.value === 1))
  );
}

/**
 * Checks whether the given node logically represents multiplication by a fraction of `1`.
 * For example, `a * 1` in `a * 1 / b` is technically multiplication by `1`, but the
 * whole expression can be logically interpreted as `a * (1 / b)` rather than `(a * 1) / b`.
 * @param {BinaryExpression} node A BinaryExpression node to check.
 * @param {SourceCode} sourceCode The source code object.
 * @returns {boolean} Whether or not the node is a multiplying by a fraction of `1`.
 */
function isMultiplyByFractionOfOne(node, sourceCode) {
  return (
    node.type === 'BinaryExpression' &&
    node.operator === '*' &&
    node.right.type === 'Literal' &&
    node.right.value === 1 &&
    node.parent.type === 'BinaryExpression' &&
    node.parent.operator === '/' &&
    node.parent.left === node &&
    !astUtils.isParenthesised(sourceCode, node)
  );
}

/**
 * Checks whether the result of a node is numeric or not
 * @param {ASTNode} node The node to test
 * @returns {boolean} true if the node is a number literal or a `Number()`, `parseInt` or `parseFloat` call
 */
function isNumeric(node) {
  return (
    (node.type === 'Literal' && typeof node.value === 'number') ||
    (node.type === 'CallExpression' &&
      (node.callee.name === 'Number' ||
        node.callee.name === 'parseInt' ||
        node.callee.name === 'parseFloat'))
  );
}

/**
 * Returns the first non-numeric operand in a BinaryExpression. Designed to be
 * used from bottom to up since it walks up the BinaryExpression trees using
 * node.parent to find the result.
 * @param {BinaryExpression} node The BinaryExpression node to be walked up on
 * @returns {ASTNode|null} The first non-numeric item in the BinaryExpression tree or null
 */
function getNonNumericOperand(node) {
  const left = node.left,
    right = node.right;

  if (right.type !== 'BinaryExpression' && !isNumeric(right)) {
    return right;
  }

  if (left.type !== 'BinaryExpression' && !isNumeric(left)) {
    return left;
  }

  return null;
}

/**
 * Checks whether an expression evaluates to a string.
 * @param {ASTNode} node node that represents the expression to check.
 * @returns {boolean} Whether or not the expression evaluates to a string.
 */
function isStringType(node) {
  return (
    astUtils.isStringLiteral(node) ||
    (node.type === 'CallExpression' &&
      node.callee.type === 'Identifier' &&
      node.callee.name === 'String')
  );
}

/**
 * Checks whether a node is an empty string literal or not.
 * @param {ASTNode} node The node to check.
 * @returns {boolean} Whether or not the passed in node is an
 * empty string literal or not.
 */
function isEmptyString(node) {
  return (
    astUtils.isStringLiteral(node) &&
    (node.value === '' ||
      (node.type === 'TemplateLiteral' &&
        node.quasis.length === 1 &&
        node.quasis[0].value.cooked === ''))
  );
}

/**
 * Checks whether or not a node is a concatenating with an empty string.
 * @param {ASTNode} node A BinaryExpression node to check.
 * @returns {boolean} Whether or not the node is a concatenating with an empty string.
 */
function isConcatWithEmptyString(node) {
  return (
    node.operator === '+' &&
    ((isEmptyString(node.left) && !isStringType(node.right)) ||
      (isEmptyString(node.right) && !isStringType(node.left)))
  );
}

/**
 * Checks whether or not a node is appended with an empty string.
 * @param {ASTNode} node An AssignmentExpression node to check.
 * @returns {boolean} Whether or not the node is appended with an empty string.
 */
function isAppendEmptyString(node) {
  return node.operator === '+=' && isEmptyString(node.right);
}

/**
 * Returns the operand that is not an empty string from a flagged BinaryExpression.
 * @param {ASTNode} node The flagged BinaryExpression node to check.
 * @returns {ASTNode} The operand that is not an empty string from a flagged BinaryExpression.
 */
function getNonEmptyOperand(node) {
  return isEmptyString(node.left) ? node.right : node.left;
}

//------------------------------------------------------------------------------
// Rule Definition
//------------------------------------------------------------------------------

/** @type {import('../types').Rule.RuleModule} */
module.exports = {
  meta: {
    hasSuggestions: true,
    type: 'suggestion',

    docs: {
      description: 'Disallow shorthand type conversions',
      recommended: false,
      frozen: true,
      url: 'https://eslint.org/docs/latest/rules/no-implicit-coercion',
    },

    fixable: 'code',

    schema: [
      {
        type: 'object',
        properties: {
          boolean: {
            type: 'boolean',
          },
          number: {
            type: 'boolean',
          },
          string: {
            type: 'boolean',
          },
          disallowTemplateShorthand: {
            type: 'boolean',
          },
          allow: {
            type: 'array',
            items: {
              enum: ALLOWABLE_OPERATORS,
            },
            uniqueItems: true,
          },
        },
        additionalProperties: false,
      },
    ],

    defaultOptions: [
      {
        allow: [],
        boolean: true,
        disallowTemplateShorthand: false,
        number: true,
        string: true,
      },
    ],

    messages: {
      implicitCoercion:
        'Unexpected implicit coercion encountered. Use `{{recommendation}}` instead.',
      useRecommendation: 'Use `{{recommendation}}` instead.',
    },
  },

  create(context) {
    const [options] = context.options;
    const sourceCode = context.sourceCode;

    /**
     * Reports an error and autofixes the node
     * @param {ASTNode} node An ast node to report the error on.
     * @param {string} recommendation The recommended code for the issue
     * @param {bool} shouldSuggest Whether this report should offer a suggestion
     * @param {bool} shouldFix Whether this report should fix the node
     * @returns {void}
     */
    function report(node, recommendation, shouldSuggest, shouldFix) {
      /**
       * Fix function
       * @param {RuleFixer} fixer The fixer to fix.
       * @returns {Fix} The fix object.
       */
      function fix(fixer) {
        const tokenBefore = sourceCode.getTokenBefore(node);

        if (
          tokenBefore?.range[1] === node.range[0] &&
          !astUtils.canTokensBeAdjacent(tokenBefore, recommendation)
        ) {
          return fixer.replaceText(node, ` ${recommendation}`);
        }

        return fixer.replaceText(node, recommendation);
      }

      context.report({
        node,
        messageId: 'implicitCoercion',
        data: { recommendation },
        fix(fixer) {
          if (!shouldFix) {
            return null;
          }

          return fix(fixer);
        },
        suggest: [
          {
            messageId: 'useRecommendation',
            data: { recommendation },
            fix(fixer) {
              if (shouldFix || !shouldSuggest) {
                return null;
              }

              return fix(fixer);
            },
          },
        ],
      });
    }

    return {
      UnaryExpression(node) {
        let operatorAllowed;

        // !!foo
        operatorAllowed = options.allow.includes('!!');
        if (
          !operatorAllowed &&
          options.boolean &&
          isDoubleLogicalNegating(node)
        ) {
          const recommendation = `Boolean(${sourceCode.getText(node.argument.argument)})`;
          const variable = astUtils.getVariableByName(
            sourceCode.getScope(node),
            'Boolean'
          );
          const booleanExists = variable?.identifiers.length === 0;

          report(node, recommendation, true, booleanExists);
        }

        // ~foo.indexOf(bar)
        operatorAllowed = options.allow.includes('~');
        if (
          !operatorAllowed &&
          options.boolean &&
          isBinaryNegatingOfIndexOf(node)
        ) {
          // `foo?.indexOf(bar) !== -1` will be true (== found) if the `foo` is nullish. So use `>= 0` in that case.
          const comparison =
            node.argument.type === 'ChainExpression' ? '>= 0' : '!== -1';
          const recommendation = `${sourceCode.getText(node.argument)} ${comparison}`;

          report(node, recommendation, false, false);
        }

        // +foo
        operatorAllowed = options.allow.includes('+');
        if (
          !operatorAllowed &&
          options.number &&
          node.operator === '+' &&
          !isNumeric(node.argument)
        ) {
          const recommendation = `Number(${sourceCode.getText(node.argument)})`;

          report(node, recommendation, true, false);
        }

        // -(-foo)
        operatorAllowed = options.allow.includes('- -');
        if (
          !operatorAllowed &&
          options.number &&
          node.operator === '-' &&
          node.argument.type === 'UnaryExpression' &&
          node.argument.operator === '-' &&
          !isNumeric(node.argument.argument)
        ) {
          const recommendation = `Number(${sourceCode.getText(node.argument.argument)})`;

          report(node, recommendation, true, false);
        }
      },

      // Use `:exit` to prevent double reporting
      'BinaryExpression:exit'(node) {
        let operatorAllowed;

        // 1 * foo
        operatorAllowed = options.allow.includes('*');
        const nonNumericOperand =
          !operatorAllowed &&
          options.number &&
          isMultiplyByOne(node) &&
          !isMultiplyByFractionOfOne(node, sourceCode) &&
          getNonNumericOperand(node);

        if (nonNumericOperand) {
          const recommendation = `Number(${sourceCode.getText(nonNumericOperand)})`;

          report(node, recommendation, true, false);
        }

        // foo - 0
        operatorAllowed = options.allow.includes('-');
        if (
          !operatorAllowed &&
          options.number &&
          node.operator === '-' &&
          node.right.type === 'Literal' &&
          node.right.value === 0 &&
          !isNumeric(node.left)
        ) {
          const recommendation = `Number(${sourceCode.getText(node.left)})`;

          report(node, recommendation, true, false);
        }

        // "" + foo
        operatorAllowed = options.allow.includes('+');
        if (
          !operatorAllowed &&
          options.string &&
          isConcatWithEmptyString(node)
        ) {
          const recommendation = `String(${sourceCode.getText(getNonEmptyOperand(node))})`;

          report(node, recommendation, true, false);
        }
      },

      AssignmentExpression(node) {
        // foo += ""
        const operatorAllowed = options.allow.includes('+');

        if (!operatorAllowed && options.string && isAppendEmptyString(node)) {
          const code = sourceCode.getText(getNonEmptyOperand(node));
          const recommendation = `${code} = String(${code})`;

          report(node, recommendation, true, false);
        }
      },

      TemplateLiteral(node) {
        if (!options.disallowTemplateShorthand) {
          return;
        }

        // tag`${foo}`
        if (node.parent.type === 'TaggedTemplateExpression') {
          return;
        }

        // `` or `${foo}${bar}`
        if (node.expressions.length !== 1) {
          return;
        }

        //  `prefix${foo}`
        if (node.quasis[0].value.cooked !== '') {
          return;
        }

        //  `${foo}postfix`
        if (node.quasis[1].value.cooked !== '') {
          return;
        }

        // if the expression is already a string, then this isn't a coercion
        if (isStringType(node.expressions[0])) {
          return;
        }

        const code = sourceCode.getText(node.expressions[0]);
        const recommendation = `String(${code})`;

        report(node, recommendation, true, false);
      },
    };
  },
};