// Copyright 2015 go-swagger maintainers
//
// 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 spec

import (
	"encoding/json"
	"fmt"
	"strconv"

	"github.com/go-openapi/jsonpointer"
)

// Dependencies represent a dependencies property
type Dependencies map[string]SchemaOrStringArray

// SchemaOrBool represents a schema or boolean value, is biased towards true for the boolean property
type SchemaOrBool struct {
	Allows bool
	Schema *Schema
}

// JSONLookup implements an interface to customize json pointer lookup
func (s SchemaOrBool) JSONLookup(token string) (interface{}, error) {
	if token == "allows" {
		return s.Allows, nil
	}
	r, _, err := jsonpointer.GetForToken(s.Schema, token)
	return r, err
}

var jsTrue = []byte("true")
var jsFalse = []byte("false")

// MarshalJSON convert this object to JSON
func (s SchemaOrBool) MarshalJSON() ([]byte, error) {
	if s.Schema != nil {
		return json.Marshal(s.Schema)
	}

	if s.Schema == nil && !s.Allows {
		return jsFalse, nil
	}
	return jsTrue, nil
}

// UnmarshalJSON converts this bool or schema object from a JSON structure
func (s *SchemaOrBool) UnmarshalJSON(data []byte) error {
	var nw SchemaOrBool
	if len(data) >= 4 {
		if data[0] == '{' {
			var sch Schema
			if err := json.Unmarshal(data, &sch); err != nil {
				return err
			}
			nw.Schema = &sch
		}
		nw.Allows = !(data[0] == 'f' && data[1] == 'a' && data[2] == 'l' && data[3] == 's' && data[4] == 'e')
	}
	*s = nw
	return nil
}

// SchemaOrStringArray represents a schema or a string array
type SchemaOrStringArray struct {
	Schema   *Schema
	Property []string
}

// JSONLookup implements an interface to customize json pointer lookup
func (s SchemaOrStringArray) JSONLookup(token string) (interface{}, error) {
	r, _, err := jsonpointer.GetForToken(s.Schema, token)
	return r, err
}

// MarshalJSON converts this schema object or array into JSON structure
func (s SchemaOrStringArray) MarshalJSON() ([]byte, error) {
	if len(s.Property) > 0 {
		return json.Marshal(s.Property)
	}
	if s.Schema != nil {
		return json.Marshal(s.Schema)
	}
	return []byte("null"), nil
}

// UnmarshalJSON converts this schema object or array from a JSON structure
func (s *SchemaOrStringArray) UnmarshalJSON(data []byte) error {
	var first byte
	if len(data) > 1 {
		first = data[0]
	}
	var nw SchemaOrStringArray
	if first == '{' {
		var sch Schema
		if err := json.Unmarshal(data, &sch); err != nil {
			return err
		}
		nw.Schema = &sch
	}
	if first == '[' {
		if err := json.Unmarshal(data, &nw.Property); err != nil {
			return err
		}
	}
	*s = nw
	return nil
}

// Definitions contains the models explicitly defined in this spec
// An object to hold data types that can be consumed and produced by operations.
// These data types can be primitives, arrays or models.
//
// For more information: http://goo.gl/8us55a#definitionsObject
type Definitions map[string]Schema

// StringOrArray represents a value that can either be a string
// or an array of strings. Mainly here for serialization purposes
type StringOrArray []string

// Contains returns true when the value is contained in the slice
func (s StringOrArray) Contains(value string) bool {
	for _, str := range s {
		if str == value {
			return true
		}
	}
	return false
}

// JSONLookup implements an interface to customize json pointer lookup
func (s SchemaOrArray) JSONLookup(token string) (interface{}, error) {
	if _, err := strconv.Atoi(token); err == nil {
		r, _, err := jsonpointer.GetForToken(s.Schemas, token)
		return r, err
	}
	r, _, err := jsonpointer.GetForToken(s.Schema, token)
	return r, err
}

// UnmarshalJSON unmarshals this string or array object from a JSON array or JSON string
func (s *StringOrArray) UnmarshalJSON(data []byte) error {
	var first byte
	if len(data) > 1 {
		first = data[0]
	}

	if first == '[' {
		var parsed []string
		if err := json.Unmarshal(data, &parsed); err != nil {
			return err
		}
		*s = StringOrArray(parsed)
		return nil
	}

	var single interface{}
	if err := json.Unmarshal(data, &single); err != nil {
		return err
	}
	if single == nil {
		return nil
	}
	switch v := single.(type) {
	case string:
		*s = StringOrArray([]string{v})
		return nil
	default:
		return fmt.Errorf("only string or array is allowed, not %T", single)
	}
}

// MarshalJSON converts this string or array to a JSON array or JSON string
func (s StringOrArray) MarshalJSON() ([]byte, error) {
	if len(s) == 1 {
		return json.Marshal([]string(s)[0])
	}
	return json.Marshal([]string(s))
}

// SchemaOrArray represents a value that can either be a Schema
// or an array of Schema. Mainly here for serialization purposes
type SchemaOrArray struct {
	Schema  *Schema
	Schemas []Schema
}

// Len returns the number of schemas in this property
func (s SchemaOrArray) Len() int {
	if s.Schema != nil {
		return 1
	}
	return len(s.Schemas)
}

// ContainsType returns true when one of the schemas is of the specified type
func (s *SchemaOrArray) ContainsType(name string) bool {
	if s.Schema != nil {
		return s.Schema.Type != nil && s.Schema.Type.Contains(name)
	}
	return false
}

// MarshalJSON converts this schema object or array into JSON structure
func (s SchemaOrArray) MarshalJSON() ([]byte, error) {
	if len(s.Schemas) > 0 {
		return json.Marshal(s.Schemas)
	}
	return json.Marshal(s.Schema)
}

// UnmarshalJSON converts this schema object or array from a JSON structure
func (s *SchemaOrArray) UnmarshalJSON(data []byte) error {
	var nw SchemaOrArray
	var first byte
	if len(data) > 1 {
		first = data[0]
	}
	if first == '{' {
		var sch Schema
		if err := json.Unmarshal(data, &sch); err != nil {
			return err
		}
		nw.Schema = &sch
	}
	if first == '[' {
		if err := json.Unmarshal(data, &nw.Schemas); err != nil {
			return err
		}
	}
	*s = nw
	return nil
}