//go:build codegen
// +build codegen

package api

import (
	"bytes"
	"encoding/json"
	"fmt"
	"os"
	"sort"
	"strings"
	"text/template"

	"github.com/aws/aws-sdk-go/private/util"
)

type Examples map[string][]Example

// ExamplesDefinition is the structural representation of the examples-1.json file
type ExamplesDefinition struct {
	*API     `json:"-"`
	Examples Examples `json:"examples"`
}

// Example is a single entry within the examples-1.json file.
type Example struct {
	API           *API                   `json:"-"`
	Operation     *Operation             `json:"-"`
	OperationName string                 `json:"-"`
	Index         string                 `json:"-"`
	Builder       examplesBuilder        `json:"-"`
	VisitedErrors map[string]struct{}    `json:"-"`
	Title         string                 `json:"title"`
	Description   string                 `json:"description"`
	ID            string                 `json:"id"`
	Comments      Comments               `json:"comments"`
	Input         map[string]interface{} `json:"input"`
	Output        map[string]interface{} `json:"output"`
}

type Comments struct {
	Input  map[string]interface{} `json:"input"`
	Output map[string]interface{} `json:"output"`
}

var exampleFuncMap = template.FuncMap{
	"commentify":           commentify,
	"wrap":                 wrap,
	"generateExampleInput": generateExampleInput,
	"generateTypes":        generateTypes,
}

var exampleCustomizations = map[string]template.FuncMap{}

var exampleTmpls = template.Must(template.New("example").Funcs(exampleFuncMap).Parse(`
{{ generateTypes . }}
{{ commentify (wrap .Title 80) }}
//
{{ commentify (wrap .Description 80) }}
func Example{{ .API.StructName }}_{{ .MethodName }}() {
	svc := {{ .API.PackageName }}.New(session.New())
	input := {{ generateExampleInput . }}

	result, err := svc.{{ .OperationName }}(input)
	if err != nil {
		if aerr, ok := err.(awserr.Error); ok {
			switch aerr.Code() {
				{{ range $_, $ref := .Operation.ErrorRefs -}}
					{{ if not ($.HasVisitedError $ref) -}}
			case {{ .API.PackageName }}.{{ $ref.Shape.ErrorCodeName }}:
				fmt.Println({{ .API.PackageName }}.{{ $ref.Shape.ErrorCodeName }}, aerr.Error())
					{{ end -}}
				{{ end -}}
			default:
				fmt.Println(aerr.Error())
			}
		} else {
			// Print the error, cast err to awserr.Error to get the Code and
			// Message from an error.
			fmt.Println(err.Error())
		}
		return
	}

	fmt.Println(result)
}
`))

// Names will return the name of the example. This will also be the name of the operation
// that is to be tested.
func (exs Examples) Names() []string {
	names := make([]string, 0, len(exs))
	for k := range exs {
		names = append(names, k)
	}

	sort.Strings(names)
	return names
}

func (exs Examples) GoCode() string {
	buf := bytes.NewBuffer(nil)
	for _, opName := range exs.Names() {
		examples := exs[opName]
		for _, ex := range examples {
			buf.WriteString(util.GoFmt(ex.GoCode()))
			buf.WriteString("\n")
		}
	}
	return buf.String()
}

// ExampleCode will generate the example code for the given Example shape.
// TODO: Can delete
func (ex Example) GoCode() string {
	var buf bytes.Buffer
	m := exampleFuncMap
	if fMap, ok := exampleCustomizations[ex.API.PackageName()]; ok {
		m = fMap
	}
	tmpl := exampleTmpls.Funcs(m)
	if err := tmpl.ExecuteTemplate(&buf, "example", &ex); err != nil {
		panic(err)
	}

	return strings.TrimSpace(buf.String())
}

func generateExampleInput(ex Example) string {
	if ex.Operation.HasInput() {
		return fmt.Sprintf("&%s{\n%s\n}",
			ex.Builder.GoType(&ex.Operation.InputRef, true),
			ex.Builder.BuildShape(&ex.Operation.InputRef, ex.Input, false),
		)
	}
	return ""
}

// generateTypes will generate no types for default examples, but customizations may
// require their own defined types.
func generateTypes(ex Example) string {
	return ""
}

// correctType will cast the value to the correct type when printing the string.
// This is due to the json decoder choosing numbers to be floats, but the shape may
// actually be an int. To counter this, we pass the shape's type and properly do the
// casting here.
func correctType(memName string, t string, value interface{}) string {
	if value == nil {
		return ""
	}

	v := ""
	switch value.(type) {
	case string:
		v = value.(string)
	case int:
		v = fmt.Sprintf("%d", value.(int))
	case float64:
		if t == "integer" || t == "long" || t == "int64" {
			v = fmt.Sprintf("%d", int(value.(float64)))
		} else {
			v = fmt.Sprintf("%f", value.(float64))
		}
	case bool:
		v = fmt.Sprintf("%t", value.(bool))
	}

	return convertToCorrectType(memName, t, v)
}

func convertToCorrectType(memName, t, v string) string {
	return fmt.Sprintf("%s: %s,\n", memName, getValue(t, v))
}

func getValue(t, v string) string {
	if t[0] == '*' {
		t = t[1:]
	}
	switch t {
	case "string":
		return fmt.Sprintf("aws.String(%q)", v)
	case "integer", "long", "int64":
		return fmt.Sprintf("aws.Int64(%s)", v)
	case "float", "float64", "double":
		return fmt.Sprintf("aws.Float64(%s)", v)
	case "boolean":
		return fmt.Sprintf("aws.Bool(%s)", v)
	default:
		panic("Unsupported type: " + t)
	}
}

// AttachExamples will create a new ExamplesDefinition from the examples file
// and reference the API object.
func (a *API) AttachExamples(filename string) error {
	p := ExamplesDefinition{API: a}

	f, err := os.Open(filename)
	defer f.Close()
	if err != nil {
		return err
	}
	err = json.NewDecoder(f).Decode(&p)
	if err != nil {
		return fmt.Errorf("failed to decode %s, err: %v", filename, err)
	}

	return p.setup()
}

var examplesBuilderCustomizations = map[string]examplesBuilder{
	"wafregional": NewWAFregionalExamplesBuilder(),
}

func (p *ExamplesDefinition) setup() error {
	var builder examplesBuilder
	ok := false
	if builder, ok = examplesBuilderCustomizations[p.API.PackageName()]; !ok {
		builder = NewExamplesBuilder()
	}

	filteredExamples := make(Examples)

	for _, n := range p.Examples.Names() {
		examples := p.Examples[n]
		n = p.ExportableName(n)
		if _, ok := p.API.Operations[n]; !ok {
			continue
		}
		filteredExamples[n] = make([]Example, 0, len(examples))
		for i, e := range examples {
			e.OperationName = n
			e.API = p.API
			e.Index = fmt.Sprintf("shared%02d", i)

			e.Builder = builder

			e.VisitedErrors = map[string]struct{}{}
			op := p.API.Operations[e.OperationName]
			e.Operation = op

			filteredExamples[n] = append(filteredExamples[n], e)
		}
	}

	p.Examples = filteredExamples
	p.API.Examples = p.Examples

	return nil
}

var exampleHeader = template.Must(template.New("exampleHeader").Parse(`
import (
	{{ .Builder.Imports .API }}
)

var _ time.Duration
var _ strings.Reader
var _ aws.Config

func parseTime(layout, value string) *time.Time {
	t, err := time.Parse(layout, value)
	if err != nil {
		panic(err)
	}
	return &t
}

`))

type exHeader struct {
	Builder examplesBuilder
	API     *API
}

// ExamplesGoCode will return a code representation of the entry within the
// examples.json file.
func (a *API) ExamplesGoCode() string {
	var buf bytes.Buffer
	var builder examplesBuilder
	ok := false
	if builder, ok = examplesBuilderCustomizations[a.PackageName()]; !ok {
		builder = NewExamplesBuilder()
	}

	if err := exampleHeader.ExecuteTemplate(&buf, "exampleHeader", &exHeader{builder, a}); err != nil {
		panic(err)
	}

	code := a.Examples.GoCode()
	if len(code) == 0 {
		return ""
	}

	buf.WriteString(code)
	return buf.String()
}

// TODO: In the operation docuentation where we list errors, this needs to be done
// there as well.
func (ex *Example) HasVisitedError(errRef *ShapeRef) bool {
	errName := errRef.Shape.ErrorCodeName()
	_, ok := ex.VisitedErrors[errName]
	ex.VisitedErrors[errName] = struct{}{}
	return ok
}

func (ex *Example) MethodName() string {
	return fmt.Sprintf("%s_%s", ex.OperationName, ex.Index)
}
