/*
   Copyright 2014 CoreOS, Inc.

   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 validate

import (
	"encoding/json"
	"fmt"
)

// Report represents the list of entries resulting from validation.
type Report struct {
	entries []Entry
}

// Error adds an error entry to the report.
func (r *Report) Error(line int, message string) {
	r.entries = append(r.entries, Entry{entryError, message, line})
}

// Warning adds a warning entry to the report.
func (r *Report) Warning(line int, message string) {
	r.entries = append(r.entries, Entry{entryWarning, message, line})
}

// Info adds an info entry to the report.
func (r *Report) Info(line int, message string) {
	r.entries = append(r.entries, Entry{entryInfo, message, line})
}

// Entries returns the list of entries in the report.
func (r *Report) Entries() []Entry {
	return r.entries
}

// Entry represents a single generic item in the report.
type Entry struct {
	kind    entryKind
	message string
	line    int
}

// String returns a human-readable representation of the entry.
func (e Entry) String() string {
	return fmt.Sprintf("line %d: %s: %s", e.line, e.kind, e.message)
}

// MarshalJSON satisfies the json.Marshaler interface, returning the entry
// encoded as a JSON object.
func (e Entry) MarshalJSON() ([]byte, error) {
	return json.Marshal(map[string]interface{}{
		"kind":    e.kind.String(),
		"message": e.message,
		"line":    e.line,
	})
}

type entryKind int

const (
	entryError entryKind = iota
	entryWarning
	entryInfo
)

func (k entryKind) String() string {
	switch k {
	case entryError:
		return "error"
	case entryWarning:
		return "warning"
	case entryInfo:
		return "info"
	default:
		panic(fmt.Sprintf("invalid kind %d", k))
	}
}