"use strict";

const _ = require("lodash");
const declarationValueIndex = require("../../utils/declarationValueIndex");
const isSingleLineString = require("../../utils/isSingleLineString");
const isStandardSyntaxFunction = require("../../utils/isStandardSyntaxFunction");
const report = require("../../utils/report");
const ruleMessages = require("../../utils/ruleMessages");
const validateOptions = require("../../utils/validateOptions");
const valueParser = require("postcss-value-parser");

const ruleName = "function-parentheses-newline-inside";

const messages = ruleMessages(ruleName, {
  expectedOpening: 'Expected newline after "("',
  expectedClosing: 'Expected newline before ")"',
  expectedOpeningMultiLine:
    'Expected newline after "(" in a multi-line function',
  rejectedOpeningMultiLine:
    'Unexpected whitespace after "(" in a multi-line function',
  expectedClosingMultiLine:
    'Expected newline before ")" in a multi-line function',
  rejectedClosingMultiLine:
    'Unexpected whitespace before ")" in a multi-line function'
});

const rule = function(expectation, options, context) {
  return (root, result) => {
    const validOptions = validateOptions(result, ruleName, {
      actual: expectation,
      possible: ["always", "always-multi-line", "never-multi-line"]
    });

    if (!validOptions) {
      return;
    }

    root.walkDecls(decl => {
      if (decl.value.indexOf("(") === -1) {
        return;
      }

      let hasFixed = false;
      const declValue = _.get(decl, "raws.value.raw", decl.value);
      const parsedValue = valueParser(declValue);

      parsedValue.walk(valueNode => {
        if (valueNode.type !== "function") {
          return;
        }

        if (!isStandardSyntaxFunction(valueNode)) {
          return;
        }

        const functionString = valueParser.stringify(valueNode);
        const isMultiLine = !isSingleLineString(functionString);

        function containsNewline(str) {
          return str.indexOf("\n") !== -1;
        }

        // Check opening ...

        const openingIndex = valueNode.sourceIndex + valueNode.value.length + 1;
        const checkBefore = getCheckBefore(valueNode);

        if (expectation === "always" && !containsNewline(checkBefore)) {
          if (context.fix) {
            hasFixed = true;
            fixBeforeForAlways(valueNode, context.newline);
          } else {
            complain(messages.expectedOpening, openingIndex);
          }
        }

        if (
          isMultiLine &&
          expectation === "always-multi-line" &&
          !containsNewline(checkBefore)
        ) {
          if (context.fix) {
            hasFixed = true;
            fixBeforeForAlways(valueNode, context.newline);
          } else {
            complain(messages.expectedOpeningMultiLine, openingIndex);
          }
        }

        if (
          isMultiLine &&
          expectation === "never-multi-line" &&
          checkBefore !== ""
        ) {
          if (context.fix) {
            hasFixed = true;
            fixBeforeForNever(valueNode);
          } else {
            complain(messages.rejectedOpeningMultiLine, openingIndex);
          }
        }

        // Check closing ...

        const closingIndex = valueNode.sourceIndex + functionString.length - 2;
        const checkAfter = getCheckAfter(valueNode);

        if (expectation === "always" && !containsNewline(checkAfter)) {
          if (context.fix) {
            hasFixed = true;
            fixAfterForAlways(valueNode, context.newline);
          } else {
            complain(messages.expectedClosing, closingIndex);
          }
        }

        if (
          isMultiLine &&
          expectation === "always-multi-line" &&
          !containsNewline(checkAfter)
        ) {
          if (context.fix) {
            hasFixed = true;
            fixAfterForAlways(valueNode, context.newline);
          } else {
            complain(messages.expectedClosingMultiLine, closingIndex);
          }
        }

        if (
          isMultiLine &&
          expectation === "never-multi-line" &&
          checkAfter !== ""
        ) {
          if (context.fix) {
            hasFixed = true;
            fixAfterForNever(valueNode);
          } else {
            complain(messages.rejectedClosingMultiLine, closingIndex);
          }
        }
      });

      if (hasFixed) {
        if (!decl.raws.value) {
          decl.value = parsedValue.toString();
        } else {
          decl.raws.value.raw = parsedValue.toString();
        }
      }

      function complain(message, offset) {
        report({
          ruleName,
          result,
          message,
          node: decl,
          index: declarationValueIndex(decl) + offset
        });
      }
    });
  };
};

function getCheckBefore(valueNode) {
  let before = valueNode.before;

  for (const node of valueNode.nodes) {
    if (node.type === "comment") {
      continue;
    }

    if (node.type === "space") {
      before += node.value;
      continue;
    }

    break;
  }

  return before;
}

function getCheckAfter(valueNode) {
  let after = "";

  for (const node of valueNode.nodes.slice().reverse()) {
    if (node.type === "comment") {
      continue;
    }

    if (node.type === "space") {
      after = node.value + after;
      continue;
    }

    break;
  }

  after += valueNode.after;

  return after;
}

function fixBeforeForAlways(valueNode, newline) {
  let target;

  for (const node of valueNode.nodes) {
    if (node.type === "comment") {
      continue;
    }

    if (node.type === "space") {
      target = node;
      continue;
    }

    break;
  }

  if (target) {
    target.value = newline + target.value;
  } else {
    valueNode.before = newline + valueNode.before;
  }
}

function fixBeforeForNever(valueNode) {
  valueNode.before = "";

  for (const node of valueNode.nodes) {
    if (node.type === "comment") {
      continue;
    }

    if (node.type === "space") {
      node.value = "";
      continue;
    }

    break;
  }
}

function fixAfterForAlways(valueNode, newline) {
  valueNode.after = newline + valueNode.after;
}

function fixAfterForNever(valueNode) {
  valueNode.after = "";

  for (const node of valueNode.nodes.slice().reverse()) {
    if (node.type === "comment") {
      continue;
    }

    if (node.type === "space") {
      node.value = "";
      continue;
    }

    break;
  }
}

rule.ruleName = ruleName;
rule.messages = messages;
module.exports = rule;