// Copyright 2011 Aaron Jacobs. All Rights Reserved.
// Author: aaronjjacobs@gmail.com (Aaron Jacobs)
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package oglematchers

import (
	"strings"
)

// AllOf accepts a set of matchers S and returns a matcher that follows the
// algorithm below when considering a candidate c:
//
//  1. Return true if for every Matcher m in S, m matches c.
//
//  2. Otherwise, if there is a matcher m in S such that m returns a fatal
//     error for c, return that matcher's error message.
//
//  3. Otherwise, return false with the error from some wrapped matcher.
//
// This is akin to a logical AND operation for matchers.
func AllOf(matchers ...Matcher) Matcher {
	return &allOfMatcher{matchers}
}

type allOfMatcher struct {
	wrappedMatchers []Matcher
}

func (m *allOfMatcher) Description() string {
	// Special case: the empty set.
	if len(m.wrappedMatchers) == 0 {
		return "is anything"
	}

	// Join the descriptions for the wrapped matchers.
	wrappedDescs := make([]string, len(m.wrappedMatchers))
	for i, wrappedMatcher := range m.wrappedMatchers {
		wrappedDescs[i] = wrappedMatcher.Description()
	}

	return strings.Join(wrappedDescs, ", and ")
}

func (m *allOfMatcher) Matches(c interface{}) (err error) {
	for _, wrappedMatcher := range m.wrappedMatchers {
		if wrappedErr := wrappedMatcher.Matches(c); wrappedErr != nil {
			err = wrappedErr

			// If the error is fatal, return immediately with this error.
			_, ok := wrappedErr.(*FatalError)
			if ok {
				return
			}
		}
	}

	return
}