/**
   * @fileoverview Require or disallow newlines around directives.
   * @author Kai Cataldo
   */
  
  "use strict";
  
  const astUtils = require("../ast-utils");
  
  //------------------------------------------------------------------------------
  // Rule Definition
  //------------------------------------------------------------------------------
  
  module.exports = {
      meta: {
          docs: {
              description: "require or disallow newlines around directives",
              category: "Stylistic Issues",
              recommended: false
          },
          schema: [{
              oneOf: [
                  {
                      enum: ["always", "never"]
                  },
                  {
                      type: "object",
                      properties: {
                          before: {
                              enum: ["always", "never"]
                          },
                          after: {
                              enum: ["always", "never"]
                          }
                      },
                      additionalProperties: false,
                      minProperties: 2
                  }
              ]
          }],
          fixable: "whitespace"
      },
  
      create(context) {
          const sourceCode = context.getSourceCode();
          const config = context.options[0] || "always";
          const expectLineBefore = typeof config === "string" ? config : config.before;
          const expectLineAfter = typeof config === "string" ? config : config.after;
  
          //--------------------------------------------------------------------------
          // Helpers
          //--------------------------------------------------------------------------
  
          /**
           * Check if node is preceded by a blank newline.
           * @param {ASTNode} node Node to check.
           * @returns {boolean} Whether or not the passed in node is preceded by a blank newline.
           */
          function hasNewlineBefore(node) {
              const tokenBefore = sourceCode.getTokenBefore(node, { includeComments: true });
              const tokenLineBefore = tokenBefore ? tokenBefore.loc.end.line : 0;
  
              return node.loc.start.line - tokenLineBefore >= 2;
          }
  
          /**
          * Gets the last token of a node that is on the same line as the rest of the node.
          * This will usually be the last token of the node, but it will be the second-to-last token if the node has a trailing
          * semicolon on a different line.
          * @param {ASTNode} node A directive node
          * @returns {Token} The last token of the node on the line
          */
          function getLastTokenOnLine(node) {
              const lastToken = sourceCode.getLastToken(node);
              const secondToLastToken = sourceCode.getTokenBefore(lastToken);
  
              return astUtils.isSemicolonToken(lastToken) && lastToken.loc.start.line > secondToLastToken.loc.end.line
                  ? secondToLastToken
                  : lastToken;
          }
  
          /**
           * Check if node is followed by a blank newline.
           * @param {ASTNode} node Node to check.
           * @returns {boolean} Whether or not the passed in node is followed by a blank newline.
           */
          function hasNewlineAfter(node) {
              const lastToken = getLastTokenOnLine(node);
              const tokenAfter = sourceCode.getTokenAfter(lastToken, { includeComments: true });
  
              return tokenAfter.loc.start.line - lastToken.loc.end.line >= 2;
          }
  
          /**
           * Report errors for newlines around directives.
           * @param {ASTNode} node Node to check.
           * @param {string} location Whether the error was found before or after the directive.
           * @param {boolean} expected Whether or not a newline was expected or unexpected.
           * @returns {void}
           */
          function reportError(node, location, expected) {
              context.report({
                  node,
                  message: "{{expected}} newline {{location}} \"{{value}}\" directive.",
                  data: {
                      expected: expected ? "Expected" : "Unexpected",
                      value: node.expression.value,
                      location
                  },
                  fix(fixer) {
                      const lastToken = getLastTokenOnLine(node);
  
                      if (expected) {
                          return location === "before" ? fixer.insertTextBefore(node, "
  ") : fixer.insertTextAfter(lastToken, "
  ");
                      }
                      return fixer.removeRange(location === "before" ? [node.range[0] - 1, node.range[0]] : [lastToken.range[1], lastToken.range[1] + 1]);
                  }
              });
          }
  
          /**
           * Check lines around directives in node
           * @param {ASTNode} node - node to check
           * @returns {void}
           */
          function checkDirectives(node) {
              const directives = astUtils.getDirectivePrologue(node);
  
              if (!directives.length) {
                  return;
              }
  
              const firstDirective = directives[0];
              const hasTokenOrCommentBefore = !!sourceCode.getTokenBefore(firstDirective, { includeComments: true });
  
              // Only check before the first directive if it is preceded by a comment or if it is at the top of
              // the file and expectLineBefore is set to "never". This is to not force a newline at the top of
              // the file if there are no comments as well as for compatibility with padded-blocks.
              if (
                  firstDirective.leadingComments && firstDirective.leadingComments.length ||
  
                  // Shebangs are not added to leading comments but are accounted for by the following.
                  node.type === "Program" && hasTokenOrCommentBefore
              ) {
                  if (expectLineBefore === "always" && !hasNewlineBefore(firstDirective)) {
                      reportError(firstDirective, "before", true);
                  }
  
                  if (expectLineBefore === "never" && hasNewlineBefore(firstDirective)) {
                      reportError(firstDirective, "before", false);
                  }
              } else if (
                  node.type === "Program" &&
                  expectLineBefore === "never" &&
                  !hasTokenOrCommentBefore &&
                  hasNewlineBefore(firstDirective)
              ) {
                  reportError(firstDirective, "before", false);
              }
  
              const lastDirective = directives[directives.length - 1];
              const statements = node.type === "Program" ? node.body : node.body.body;
  
              // Do not check after the last directive if the body only
              // contains a directive prologue and isn't followed by a comment to ensure
              // this rule behaves well with padded-blocks.
              if (lastDirective === statements[statements.length - 1] && !lastDirective.trailingComments) {
                  return;
              }
  
              if (expectLineAfter === "always" && !hasNewlineAfter(lastDirective)) {
                  reportError(lastDirective, "after", true);
              }
  
              if (expectLineAfter === "never" && hasNewlineAfter(lastDirective)) {
                  reportError(lastDirective, "after", false);
              }
          }
  
          //--------------------------------------------------------------------------
          // Public
          //--------------------------------------------------------------------------
  
          return {
              Program: checkDirectives,
              FunctionDeclaration: checkDirectives,
              FunctionExpression: checkDirectives,
              ArrowFunctionExpression: checkDirectives
          };
      }
  };