/**
   * @fileoverview Rule to flag missing semicolons.
   * @author Nicholas C. Zakas
   */
  "use strict";
  
  //------------------------------------------------------------------------------
  // Requirements
  //------------------------------------------------------------------------------
  
  const FixTracker = require("../util/fix-tracker");
  const astUtils = require("../ast-utils");
  
  //------------------------------------------------------------------------------
  // Rule Definition
  //------------------------------------------------------------------------------
  
  module.exports = {
      meta: {
          docs: {
              description: "require or disallow semicolons instead of ASI",
              category: "Stylistic Issues",
              recommended: false
          },
  
          fixable: "code",
  
          schema: {
              anyOf: [
                  {
                      type: "array",
                      items: [
                          {
                              enum: ["never"]
                          }
                      ],
                      minItems: 0,
                      maxItems: 1
                  },
                  {
                      type: "array",
                      items: [
                          {
                              enum: ["always"]
                          },
                          {
                              type: "object",
                              properties: {
                                  omitLastInOneLineBlock: { type: "boolean" }
                              },
                              additionalProperties: false
                          }
                      ],
                      minItems: 0,
                      maxItems: 2
                  }
              ]
          }
      },
  
      create(context) {
  
          const OPT_OUT_PATTERN = /^[-[(/+`]/; // One of [(/+-`
          const options = context.options[1];
          const never = context.options[0] === "never",
              exceptOneLine = options && options.omitLastInOneLineBlock === true,
              sourceCode = context.getSourceCode();
  
          //--------------------------------------------------------------------------
          // Helpers
          //--------------------------------------------------------------------------
  
          /**
           * Reports a semicolon error with appropriate location and message.
           * @param {ASTNode} node The node with an extra or missing semicolon.
           * @param {boolean} missing True if the semicolon is missing.
           * @returns {void}
           */
          function report(node, missing) {
              const lastToken = sourceCode.getLastToken(node);
              let message,
                  fix,
                  loc = lastToken.loc;
  
              if (!missing) {
                  message = "Missing semicolon.";
                  loc = loc.end;
                  fix = function(fixer) {
                      return fixer.insertTextAfter(lastToken, ";");
                  };
              } else {
                  message = "Extra semicolon.";
                  loc = loc.start;
                  fix = function(fixer) {
  
                      // Expand the replacement range to include the surrounding
                      // tokens to avoid conflicting with no-extra-semi.
                      // https://github.com/eslint/eslint/issues/7928
                      return new FixTracker(fixer, sourceCode)
                          .retainSurroundingTokens(lastToken)
                          .remove(lastToken);
                  };
              }
  
              context.report({
                  node,
                  loc,
                  message,
                  fix
              });
  
          }
  
          /**
           * Check if a semicolon is unnecessary, only true if:
           *   - next token is on a new line and is not one of the opt-out tokens
           *   - next token is a valid statement divider
           * @param {Token} lastToken last token of current node.
           * @returns {boolean} whether the semicolon is unnecessary.
           */
          function isUnnecessarySemicolon(lastToken) {
              if (!astUtils.isSemicolonToken(lastToken)) {
                  return false;
              }
  
              const nextToken = sourceCode.getTokenAfter(lastToken);
  
              if (!nextToken) {
                  return true;
              }
  
              const lastTokenLine = lastToken.loc.end.line;
              const nextTokenLine = nextToken.loc.start.line;
              const isOptOutToken = OPT_OUT_PATTERN.test(nextToken.value) && nextToken.value !== "++" && nextToken.value !== "--";
              const isDivider = (astUtils.isClosingBraceToken(nextToken) || astUtils.isSemicolonToken(nextToken));
  
              return (lastTokenLine !== nextTokenLine && !isOptOutToken) || isDivider;
          }
  
          /**
           * Checks a node to see if it's in a one-liner block statement.
           * @param {ASTNode} node The node to check.
           * @returns {boolean} whether the node is in a one-liner block statement.
           */
          function isOneLinerBlock(node) {
              const nextToken = sourceCode.getTokenAfter(node);
  
              if (!nextToken || nextToken.value !== "}") {
                  return false;
              }
  
              const parent = node.parent;
  
              return parent && parent.type === "BlockStatement" &&
                parent.loc.start.line === parent.loc.end.line;
          }
  
          /**
           * Checks a node to see if it's followed by a semicolon.
           * @param {ASTNode} node The node to check.
           * @returns {void}
           */
          function checkForSemicolon(node) {
              const lastToken = sourceCode.getLastToken(node);
  
              if (never) {
                  if (isUnnecessarySemicolon(lastToken)) {
                      report(node, true);
                  }
              } else {
                  if (!astUtils.isSemicolonToken(lastToken)) {
                      if (!exceptOneLine || !isOneLinerBlock(node)) {
                          report(node);
                      }
                  } else {
                      if (exceptOneLine && isOneLinerBlock(node)) {
                          report(node, true);
                      }
                  }
              }
          }
  
          /**
           * Checks to see if there's a semicolon after a variable declaration.
           * @param {ASTNode} node The node to check.
           * @returns {void}
           */
          function checkForSemicolonForVariableDeclaration(node) {
              const ancestors = context.getAncestors(),
                  parentIndex = ancestors.length - 1,
                  parent = ancestors[parentIndex];
  
              if ((parent.type !== "ForStatement" || parent.init !== node) &&
                  (!/^For(?:In|Of)Statement/.test(parent.type) || parent.left !== node)
              ) {
                  checkForSemicolon(node);
              }
          }
  
          //--------------------------------------------------------------------------
          // Public API
          //--------------------------------------------------------------------------
  
          return {
              VariableDeclaration: checkForSemicolonForVariableDeclaration,
              ExpressionStatement: checkForSemicolon,
              ReturnStatement: checkForSemicolon,
              ThrowStatement: checkForSemicolon,
              DoWhileStatement: checkForSemicolon,
              DebuggerStatement: checkForSemicolon,
              BreakStatement: checkForSemicolon,
              ContinueStatement: checkForSemicolon,
              ImportDeclaration: checkForSemicolon,
              ExportAllDeclaration: checkForSemicolon,
              ExportNamedDeclaration(node) {
                  if (!node.declaration) {
                      checkForSemicolon(node);
                  }
              },
              ExportDefaultDeclaration(node) {
                  if (!/(?:Class|Function)Declaration/.test(node.declaration.type)) {
                      checkForSemicolon(node);
                  }
              }
          };
  
      }
  };