/*
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 candiedyaml

import (
	"bytes"
	"errors"
	"math"
	"time"

	. "github.com/onsi/ginkgo"
	. "github.com/onsi/gomega"
)

var _ = Describe("Encode", func() {
	var buf *bytes.Buffer
	var enc *Encoder

	BeforeEach(func() {
		buf = &bytes.Buffer{}
		enc = NewEncoder(buf)
	})

	Context("Scalars", func() {
		It("handles strings", func() {
			err := enc.Encode("abc")
			Expect(err).NotTo(HaveOccurred())
			Expect(buf.String()).To(Equal(`abc
`))

		})

		It("handles really short strings", func() {
			err := enc.Encode(".")
			Expect(err).NotTo(HaveOccurred())
			Expect(buf.String()).To(Equal(`.
`))

		})

		It("encodes strings with multilines", func() {
			err := enc.Encode("a\nc")
			Expect(err).NotTo(HaveOccurred())
			Expect(buf.String()).To(Equal(`|-
  a
  c
`))

		})

		It("handles strings that match known scalars", func() {
			err := enc.Encode("true")
			Expect(err).NotTo(HaveOccurred())
			Expect(buf.String()).To(Equal(`"true"
`))

		})

		It("handles strings that contain colons followed by whitespace", func() {
			err := enc.Encode("contains: colon")
			Expect(err).NotTo(HaveOccurred())
			Expect(buf.String()).To(Equal(`'contains: colon'
`))

		})

		Context("handles ints", func() {
			It("handles ints", func() {
				err := enc.Encode(13)
				Expect(err).NotTo(HaveOccurred())
				Expect(buf.String()).To(Equal("13\n"))
			})

			It("handles uints", func() {
				err := enc.Encode(uint64(1))
				Expect(err).NotTo(HaveOccurred())
				Expect(buf.String()).To(Equal("1\n"))
			})
		})

		Context("handles floats", func() {
			It("handles float32", func() {
				err := enc.Encode(float32(1.234))
				Expect(err).NotTo(HaveOccurred())
				Expect(buf.String()).To(Equal("1.234\n"))

			})

			It("handles float64", func() {
				err := enc.Encode(float64(1.2e23))
				Expect(err).NotTo(HaveOccurred())
				Expect(buf.String()).To(Equal("1.2e+23\n"))
			})

			It("handles NaN", func() {
				err := enc.Encode(math.NaN())
				Expect(err).NotTo(HaveOccurred())
				Expect(buf.String()).To(Equal(".nan\n"))
			})

			It("handles infinity", func() {
				err := enc.Encode(math.Inf(-1))
				Expect(err).NotTo(HaveOccurred())
				Expect(buf.String()).To(Equal("-.inf\n"))
			})
		})

		It("handles bools", func() {
			err := enc.Encode(true)
			Expect(err).NotTo(HaveOccurred())
			Expect(buf.String()).To(Equal("true\n"))
		})

		It("handles time.Time", func() {
			t := time.Now()
			err := enc.Encode(t)
			Expect(err).NotTo(HaveOccurred())
			bytes, _ := t.MarshalText()
			Expect(buf.String()).To(Equal(string(bytes) + "\n"))
		})

		Context("Null", func() {
			It("fails on nil", func() {
				err := enc.Encode(nil)
				Expect(err).To(HaveOccurred())
			})
		})

		It("handles []byte", func() {
			err := enc.Encode([]byte{'a', 'b', 'c'})
			Expect(err).NotTo(HaveOccurred())
			Expect(buf.String()).To(Equal("!!binary YWJj\n"))
		})

		Context("Ptrs", func() {
			It("handles ptr of a type", func() {
				p := new(int)
				*p = 10
				err := enc.Encode(p)
				Expect(err).NotTo(HaveOccurred())
				Expect(buf.String()).To(Equal("10\n"))
			})

			It("handles nil ptr", func() {
				var p *int
				err := enc.Encode(p)
				Expect(err).NotTo(HaveOccurred())
				Expect(buf.String()).To(Equal("null\n"))
			})
		})

		Context("Structs", func() {
			It("handles simple structs", func() {
				type batter struct {
					Name string
					HR   int64
					AVG  float64
				}

				batters := []batter{
					batter{Name: "Mark McGwire", HR: 65, AVG: 0.278},
					batter{Name: "Sammy Sosa", HR: 63, AVG: 0.288},
				}
				err := enc.Encode(batters)
				Expect(err).NotTo(HaveOccurred())
				Expect(buf.String()).To(Equal(`- Name: Mark McGwire
  HR: 65
  AVG: 0.278
- Name: Sammy Sosa
  HR: 63
  AVG: 0.288
`))

			})

			It("handles tagged structs", func() {
				type batter struct {
					Name string `yaml:"name"`
					HR   int64
					AVG  float64 `yaml:"avg"`
				}

				batters := []batter{
					batter{Name: "Mark McGwire", HR: 65, AVG: 0.278},
					batter{Name: "Sammy Sosa", HR: 63, AVG: 0.288},
				}
				err := enc.Encode(batters)
				Expect(err).NotTo(HaveOccurred())
				Expect(buf.String()).To(Equal(`- name: Mark McGwire
  HR: 65
  avg: 0.278
- name: Sammy Sosa
  HR: 63
  avg: 0.288
`))

			})

			It("handles nested structs", func() {
				type nestedConfig struct {
					AString string `yaml:"str"`
					Integer int    `yaml:"int"`
				}
				type config struct {
					TopString string
					Nested    nestedConfig
				}

				cfg := config{
					TopString: "def",
					Nested: nestedConfig{
						AString: "abc",
						Integer: 123,
					},
				}

				err := enc.Encode(cfg)
				Expect(err).NotTo(HaveOccurred())

				Expect(buf.String()).To(Equal(`TopString: def
Nested:
  str: abc
  int: 123
`))

			})

			It("handles inline structs", func() {
				type NestedConfig struct {
					AString string `yaml:"str"`
					Integer int    `yaml:"int"`
				}
				type config struct {
					TopString string
					NestedConfig
				}

				cfg := config{
					TopString: "def",
					NestedConfig: NestedConfig{
						AString: "abc",
						Integer: 123,
					},
				}

				err := enc.Encode(cfg)
				Expect(err).NotTo(HaveOccurred())

				Expect(buf.String()).To(Equal(`TopString: def
str: abc
int: 123
`))

			})

			It("handles inline structs with conflicts", func() {
				type NestedConfig struct {
					AString string `yaml:"str"`
					Integer int    `yaml:"int"`
				}
				type config struct {
					AString string `yaml:"str"`
					NestedConfig
				}

				cfg := config{
					AString: "def",
					NestedConfig: NestedConfig{
						AString: "abc",
						Integer: 123,
					},
				}

				err := enc.Encode(cfg)
				Expect(err).NotTo(HaveOccurred())

				Expect(buf.String()).To(Equal(`str: def
int: 123
`))

			})

		})

	})

	Context("Sequence", func() {
		It("handles slices", func() {
			val := []string{"a", "b", "c"}
			err := enc.Encode(val)
			Expect(err).NotTo(HaveOccurred())

			Expect(buf.String()).To(Equal(`- a
- b
- c
`))

		})
	})

	Context("Maps", func() {
		It("Encodes simple maps", func() {
			err := enc.Encode(&map[string]string{
				"name": "Mark McGwire",
				"hr":   "65",
				"avg":  "0.278",
			})
			Expect(err).NotTo(HaveOccurred())

			Expect(buf.String()).To(Equal(`avg: "0.278"
hr: "65"
name: Mark McGwire
`))
		})

		It("sorts by key when strings otherwise by kind", func() {
			err := enc.Encode(&map[interface{}]string{
				1.2:    "float",
				8:      "integer",
				"name": "Mark McGwire",
				"hr":   "65",
				"avg":  "0.278",
			})
			Expect(err).NotTo(HaveOccurred())

			Expect(buf.String()).To(Equal(`8: integer
1.2: float
avg: "0.278"
hr: "65"
name: Mark McGwire
`))
		})

		It("encodes mix types", func() {
			err := enc.Encode(&map[string]interface{}{
				"name": "Mark McGwire",
				"hr":   65,
				"avg":  0.278,
			})
			Expect(err).NotTo(HaveOccurred())

			Expect(buf.String()).To(Equal(`avg: 0.278
hr: 65
name: Mark McGwire
`))
		})
	})

	Context("Sequence of Maps", func() {
		It("encodes", func() {
			err := enc.Encode([]map[string]interface{}{
				{"name": "Mark McGwire",
					"hr":  65,
					"avg": 0.278,
				},
				{"name": "Sammy Sosa",
					"hr":  63,
					"avg": 0.288,
				},
			})
			Expect(err).NotTo(HaveOccurred())

			Expect(buf.String()).To(Equal(`- avg: 0.278
  hr: 65
  name: Mark McGwire
- avg: 0.288
  hr: 63
  name: Sammy Sosa
`))

		})
	})

	Context("Maps of Sequence", func() {
		It("encodes", func() {
			err := enc.Encode(map[string][]interface{}{
				"name": []interface{}{"Mark McGwire", "Sammy Sosa"},
				"hr":   []interface{}{65, 63},
				"avg":  []interface{}{0.278, 0.288},
			})
			Expect(err).NotTo(HaveOccurred())

			Expect(buf.String()).To(Equal(`avg:
- 0.278
- 0.288
hr:
- 65
- 63
name:
- Mark McGwire
- Sammy Sosa
`))

		})
	})

	Context("Flow", func() {
		It("flows structs", func() {
			type i struct {
				A string
			}
			type o struct {
				I i `yaml:"i,flow"`
			}

			err := enc.Encode(o{
				I: i{A: "abc"},
			})
			Expect(err).NotTo(HaveOccurred())
			Expect(buf.String()).To(Equal(`i: {A: abc}
`))

		})

		It("flows sequences", func() {
			type i struct {
				A string
			}
			type o struct {
				I []i `yaml:"i,flow"`
			}

			err := enc.Encode(o{
				I: []i{{A: "abc"}},
			})
			Expect(err).NotTo(HaveOccurred())
			Expect(buf.String()).To(Equal(`i: [{A: abc}]
`))

		})
	})

	Context("Omit empty", func() {
		It("omits nil ptrs", func() {
			type i struct {
				A *string `yaml:"a,omitempty"`
			}
			type o struct {
				I []i `yaml:"i,flow"`
			}

			err := enc.Encode(o{
				I: []i{{A: nil}},
			})
			Expect(err).NotTo(HaveOccurred())
			Expect(buf.String()).To(Equal(`i: [{}]
`))

		})

	})

	Context("Skip field", func() {
		It("does not include the field", func() {
			type a struct {
				B string `yaml:"-"`
				C string
			}

			err := enc.Encode(a{B: "b", C: "c"})
			Expect(err).NotTo(HaveOccurred())
			Expect(buf.String()).To(Equal(`C: c
`))

		})
	})

	Context("Marshaler support", func() {
		Context("Receiver is a value", func() {
			It("uses the Marshaler interface when a value", func() {
				err := enc.Encode(hasMarshaler{Value: 123})
				Expect(err).NotTo(HaveOccurred())
				Expect(buf.String()).To(Equal("123\n"))
			})

			It("uses the Marshaler interface when a pointer", func() {
				err := enc.Encode(&hasMarshaler{Value: "abc"})
				Expect(err).NotTo(HaveOccurred())
				Expect(buf.String()).To(Equal(`abc
`))
			})

			Context("when it fails", func() {
				It("returns an error", func() {
					err := enc.Encode(&hasMarshaler{Value: "abc", Error: errors.New("fail")})
					Expect(err).To(MatchError("fail"))
				})
			})
		})

		Context("Receiver is a pointer", func() {
			It("uses the Marshaler interface when a pointer", func() {
				err := enc.Encode(&hasPtrMarshaler{Value: map[string]string{"a": "b"}})
				Expect(err).NotTo(HaveOccurred())
				Expect(buf.String()).To(Equal(`a: b
`))

			})

			It("skips the Marshaler when its a value", func() {
				err := enc.Encode(hasPtrMarshaler{Value: map[string]string{"a": "b"}})
				Expect(err).NotTo(HaveOccurred())
				Expect(buf.String()).To(Equal(`Tag: ""
Value:
  a: b
Error: null
`))

			})

			Context("the receiver is nil", func() {
				var ptr *hasPtrMarshaler

				Context("when it fails", func() {
					It("returns an error", func() {
						err := enc.Encode(&hasPtrMarshaler{Value: "abc", Error: errors.New("fail")})
						Expect(err).To(MatchError("fail"))
					})
				})

				It("returns a null", func() {
					err := enc.Encode(ptr)
					Expect(err).NotTo(HaveOccurred())
					Expect(buf.String()).To(Equal(`null
`))

				})

				It("returns a null value for ptr types", func() {
					err := enc.Encode(map[string]*hasPtrMarshaler{"a": ptr})
					Expect(err).NotTo(HaveOccurred())
					Expect(buf.String()).To(Equal(`a: null
`))

				})

				It("panics when used as a nil interface", func() {
					Expect(func() { enc.Encode(map[string]Marshaler{"a": ptr}) }).To(Panic())
				})
			})

			Context("the receiver has a nil value", func() {
				ptr := &hasPtrMarshaler{Value: nil}

				It("returns null", func() {
					err := enc.Encode(ptr)
					Expect(err).NotTo(HaveOccurred())
					Expect(buf.String()).To(Equal(`null
`))

				})

				Context("in a map", func() {
					It("returns a null value for ptr types", func() {
						err := enc.Encode(map[string]*hasPtrMarshaler{"a": ptr})
						Expect(err).NotTo(HaveOccurred())
						Expect(buf.String()).To(Equal(`a: null
`))

					})

					It("returns a null value for interface types", func() {
						err := enc.Encode(map[string]Marshaler{"a": ptr})
						Expect(err).NotTo(HaveOccurred())
						Expect(buf.String()).To(Equal(`a: null
`))

					})
				})

				Context("in a slice", func() {
					It("returns a null value for ptr types", func() {
						err := enc.Encode([]*hasPtrMarshaler{ptr})
						Expect(err).NotTo(HaveOccurred())
						Expect(buf.String()).To(Equal(`- null
`))

					})

					It("returns a null value for interface types", func() {
						err := enc.Encode([]Marshaler{ptr})
						Expect(err).NotTo(HaveOccurred())
						Expect(buf.String()).To(Equal(`- null
`))

					})
				})
			})
		})
	})

	Context("Number type", func() {
		It("encodes as a number", func() {
			n := Number("12345")
			err := enc.Encode(n)
			Expect(err).NotTo(HaveOccurred())
			Expect(buf.String()).To(Equal("12345\n"))
		})
	})
})

type hasMarshaler struct {
	Value interface{}
	Error error
}

func (m hasMarshaler) MarshalYAML() (string, interface{}, error) {
	return "", m.Value, m.Error
}

func (m hasMarshaler) UnmarshalYAML(tag string, value interface{}) error {
	m.Value = value
	return nil
}

type hasPtrMarshaler struct {
	Tag   string
	Value interface{}
	Error error
}

func (m *hasPtrMarshaler) MarshalYAML() (string, interface{}, error) {
	return "", m.Value, m.Error
}

func (m *hasPtrMarshaler) UnmarshalYAML(tag string, value interface{}) error {
	m.Tag = tag
	m.Value = value
	return nil
}