package models

import (
	"bufio"
	"encoding"
	"encoding/json"
	"strings"
	"testing"
	"time"

	"github.com/stretchr/testify/assert"
)

// Type assertions
var _ encoding.TextMarshaler = Entry{}
var _ encoding.TextUnmarshaler = new(Entry)
var _ json.Marshaler = Entry{}
var _ json.Unmarshaler = new(Entry)

func TestEntryMarshal(t *testing.T) {
	when := time.Now()
	whens := when.Format(DateFormat)
	simple := []Meta{}
	nolines := []string{}
	tests := []struct {
		name   string
		title  string
		date   time.Time
		fields []Meta
		first  string
		lines  []string
		err    error
	}{
		{"no-title", "", when, simple, "", nolines, ErrorMissingTitle},
		{"zero-date", "Empty title", time.Time{}, simple, "", nolines, ErrorMissingDate},
		{"one-line", "A Title", when, simple, "@begin " + whens + " - A Title @end", nolines, nil},
		{
			"one-field",
			"Title 2",
			when,
			[]Meta{{"age", 41}},
			"@begin " + whens + " - Title 2",
			[]string{"@age 41 @end"},
			nil,
		},
		{
			"three-fields",
			"Title 3",
			when,
			[]Meta{{"age", 41}, {"cool", true}, {"name", "Jim"}},
			"@begin " + whens + " - Title 3",
			[]string{"@age 41", "@cool true", "@name Jim"},
			nil,
		},
		{
			"json-field",
			"Title J",
			when,
			[]Meta{{"json", json.RawMessage(`{"age": 41, "cool": true, "name": "Jim"}`)}},
			"@begin " + whens + " - Title J",
			[]string{"@age 41", "@cool true", "@name Jim"},
			nil,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, getEntryMarshalTestRunner(tt.title, tt.date, tt.fields, tt.first, tt.lines, tt.err))
	}
}

func getEntryMarshalTestRunner(title string, date time.Time, fields []Meta, first string, lines []string, err error) func(*testing.T) {
	return func(t *testing.T) {
		en := Entry{title, date, fields}
		o, er := en.MarshalText()
		assert.Equal(t, err, er)
		if first == "" {
			return
		}
		os := string(o)
		if len(lines) == 0 {
			assert.Equal(t, first, os)
			return
		}

		assert.Regexp(t, first, os)
		for _, line := range lines {
			assert.Regexp(t, "(?m)^"+line, os)
		}
	}
}

func TestEntryUnmarshal(t *testing.T) {
	when := time.Now()
	whens := when.Format(DateFormat)
	simple := []Meta{}
	tests := []struct {
		name   string
		in     string
		title  string
		date   time.Time
		fields []Meta
		err    error
	}{
		{"one-line", "@begin " + whens + " - A Title @end", "A Title", when, simple, nil},
		{"rfc3999-date", "@begin " + when.Format(time.RFC3339) + " - A Title @end", "A Title", when, simple, nil},
		{"multi-title", "@begin " + whens + " - A Title\nwith break @end", "A Title\nwith break", when, simple, nil},
		{"no-title", "@begin " + whens + " -   @end", "", when, simple, ErrorMissingTitle},
		{"parse-error", "this is no good", "", when, simple, ErrorParsing},
		{"no-date", "@begin   - A Title @end", "A Title", when, simple, ErrorMissingDate},
		{"bad-date", "@begin not-a-real date  - A Title @end", "A Title", when, simple, ErrorParsing},
		{"one-field", "@begin " + whens + " - A Title\n@age 41 @end", "A Title", when, []Meta{{"age", 41}}, nil},
		{
			"two-fields",
			"@begin " + whens + " - A Title\n@age 41\n@cool true @end",
			"A Title",
			when,
			[]Meta{{"age", 41}, {"cool", true}},
			nil,
		},
		{
			"obj-field",
			"@begin " + whens + " - A Title\n" + `@me {"name":"Dan","coder":true} @end`,
			"A Title",
			when,
			[]Meta{{"me", json.RawMessage(`{"name":"Dan","coder":true}`)}},
			nil,
		},
		{
			"json-field",
			"@begin " + whens + " - Some Guy\n" + `@json {"name":"Dan","coder":true} @end`,
			"Some Guy",
			when,
			[]Meta{{"name", "Dan"}, {"coder", true}},
			nil,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, getEntryUnmarshalTestRunner(tt.in, tt.title, tt.date, tt.fields, tt.err))
	}
}

func getEntryUnmarshalTestRunner(in string, title string, date time.Time, fields []Meta, err error) func(*testing.T) {
	return func(t *testing.T) {
		e := &Entry{}
		er := e.UnmarshalText([]byte(in))
		if err != nil {
			assert.ErrorIs(t, er, err)
			return
		}

		assert.Equal(t, title, e.Title)
		assert.WithinRange(t, e.Date, date.Add(-time.Second), date.Add(time.Second))
		for _, f := range fields {
			got := false
			for _, m := range e.Fields {
				var mVal any = m.Value
				var fVal any = f.Value
				if mJ, ok := m.Value.(json.RawMessage); ok {
					mVal = string(mJ)
				}
				if fJ, ok := f.Value.(json.RawMessage); ok {
					fVal = string(fJ)
				}
				if m.Key == f.Key && mVal == fVal {
					got = true
					break
				}
			}
			assert.Truef(t, got, "Couldn't find field %+v. We have %+v", f, e.Fields)
		}
	}
}

func TestScan(t *testing.T) {
	in := "@begin date - Title\nlong\n@foo john\njones\n@bar 42@nobody @end"
	read := strings.NewReader(in)
	scan := bufio.NewScanner(read)
	scan.Split(scanEntry)
	assert.True(t, scan.Scan())
	assert.Equal(t, "@begin date - Title\nlong", scan.Text())
	assert.True(t, scan.Scan())
	assert.Equal(t, "@foo john\njones", scan.Text())
	assert.True(t, scan.Scan())
	assert.Equal(t, "@bar 42@nobody", scan.Text())
	assert.False(t, scan.Scan())
}

func TestEntryJsonMarshal(t *testing.T) {
	when := time.Now()
	whens := when.Format(time.RFC3339)
	simple := []Meta{}
	tests := []struct {
		name   string
		title  string
		date   time.Time
		fields []Meta
		out    string
		err    error
	}{
		{"simple", "A Title", when, simple, `{"title":"A Title","date":"` + whens + `"}`, nil},
		{"one-field", "A Title 2", when, []Meta{{"age", 41}}, `{"title":"A Title 2","date":"` + whens + `","age":41}`, nil},
		{"skip-title-field", "A Title", when, []Meta{{"title", "Different title"}}, `{"title":"A Title","date":"` + whens + `"}`, nil},
		{"skip-date-field", "A Title", when, []Meta{{"date", when.Add(time.Hour)}}, `{"title":"A Title","date":"` + whens + `"}`, nil},
		{"skip-dupe-field", "A Title", when, []Meta{{"foo", "bar"}, {"foo", "baz"}}, `{"title":"A Title","date":"` + whens + `","foo": "bar"}`, nil},
		{"two-fields", "A Title", when, []Meta{{"foo", "bar"}, {"baz", 42}}, `{"title":"A Title","date":"` + whens + `","foo": "bar","baz":42}`, nil},
		{"empty-title", "", when, simple, "", ErrorMissingTitle},
		{"empty-date", "A Title", time.Time{}, simple, "", ErrorMissingDate},
		{"obj-field", "A Title", when, []Meta{{"obj", json.RawMessage(`{"foo":"bar","title":"Sub-title"}`)}}, `{"title":"A Title","date":"` + whens + `","obj":{"foo":"bar","title":"Sub-title"}}`, nil},
		{"date-field", "A Title", when, []Meta{{"when", when.Add(time.Hour)}}, `{"title":"A Title","date":"` + whens + `","when":"` + when.Add(time.Hour).Format(time.RFC3339) + `"}`, nil},
		{"json-field", "A Title", when, []Meta{{"json", json.RawMessage(`{"age": 41, "cool": true, "name": "Jim"}`)}}, `{"title":"A Title","date":"` + whens + `","age":41,"cool": true, "name": "Jim"}`, nil},
	}

	for _, tt := range tests {
		t.Run(tt.name, getEntryJsonMarshalTestRunner(tt.title, tt.date, tt.fields, tt.out, tt.err))
	}
}

func getEntryJsonMarshalTestRunner(title string, date time.Time, fields []Meta, out string, err error) func(t *testing.T) {
	return func(t *testing.T) {
		e := Entry{title, date, fields}
		o, er := json.Marshal(e)
		if err == nil {
			assert.JSONEq(t, out, string(o))

		} else {
			assert.ErrorIs(t, er, err)
		}
	}
}

func TestEntryJsonUnmarshal(t *testing.T) {
	when := time.Now().Truncate(time.Second)
	whens := when.Format(time.RFC3339)
	simple := []Meta{}
	tests := []struct {
		name   string
		in     string
		title  string
		date   time.Time
		fields []Meta
		err    error
	}{
		{"simple", `{"title":"A Title","date":"` + whens + `"}`, "A Title", when, simple, nil},
		{"missing-title", `{"date":"` + whens + `"}`, "", when, simple, ErrorMissingTitle},
		{"missing-date", `{"title":"A Title"}`, "", when, simple, ErrorMissingDate},
		{"empty-title", `{"title":"","date":"` + whens + `"}`, "", when, simple, ErrorMissingTitle},
		{"empty-date", `{"title":"A Title","date":""}`, "", when, simple, ErrorMissingDate},
		{"bad-date", `{"title":"A Title","date":"bad"}`, "", when, simple, ErrorParsing},
		{"bad-json", `{"title":"A Title","date":"`, "", when, simple, ErrorParsing},
		{
			"single-field",
			`{"title":"A Title","date":"` + whens + `","hello":"Hi"}`,
			"A Title",
			when,
			[]Meta{{"hello", "Hi"}},
			nil,
		},
		{
			"many-fields",
			`{"title":"A Title","date":"` + whens + `","hello":"Hi","bye":42,"b":true,"fl":42.13}`,
			"A Title",
			when,
			[]Meta{{"hello", "Hi"}, {"bye", int64(42)}, {"b", true}, {"fl", float64(42.13)}},
			nil,
		},
		{
			"date-field",
			`{"title":"A Title","date":"` + whens + `","posted":"` + when.Add(-time.Hour).In(time.UTC).Format(time.RFC3339) + `"}`,
			"A Title",
			when,
			[]Meta{{"posted", when.Add(-time.Hour)}},
			nil,
		},
		{
			"json-field",
			`{"title":"A Title","date":"` + whens + `","json":{"age": 41, "cool": true, "name": "Jim"}}`,
			"A Title",
			when,
			[]Meta{{"age", int64(41)}, {"cool", true}, {"name", "Jim"}},
			nil,
		},
		{
			"json-field-embed",
			`{"title":"A Title","date":"` + whens + `","json":"{\"age\": 41, \"cool\": true, \"name\": \"Jim\"}"}`,
			"A Title",
			when,
			[]Meta{{"age", int64(41)}, {"cool", true}, {"name", "Jim"}},
			nil,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, getEntryJsonUnmarshalTestRunner(tt.in, tt.title, tt.date, tt.fields, tt.err))
	}
}

func getEntryJsonUnmarshalTestRunner(in, title string, date time.Time, fields []Meta, err error) func(t *testing.T) {
	return func(t *testing.T) {
		e := new(Entry)
		er := e.UnmarshalJSON([]byte(in))
		if err != nil {
			assert.ErrorIs(t, er, err)
			return
		}

		assert.Nil(t, er)
		assert.Equal(t, title, e.Title)
		assert.WithinRange(t, e.Date, date.Add(-time.Second), date.Add(time.Second))
		assert.Len(t, e.Fields, len(fields))
		for _, f := range fields {
			got := false
			fTime, isTime := f.Value.(time.Time)
			for _, m := range e.Fields {
				var mVal any = m.Value
				var fVal any = f.Value
				if mJ, ok := m.Value.(json.RawMessage); ok {
					mVal = string(mJ)
				}
				if fJ, ok := f.Value.(json.RawMessage); ok {
					fVal = string(fJ)
				}
				if m.Key == f.Key && mVal == fVal {
					got = true
					break
				}
				if isTime && m.Key == f.Key {
					mTime, _ := mVal.(time.Time)
					if assert.WithinRange(t, mTime, fTime.Add(-2*time.Second), fTime.Add(2*time.Second)) {
						got = true
						break
					}
				}
			}
			assert.Truef(t, got, "Couldn't find field %+v. We have %+v", f, e.Fields)
		}
	}
}