package test

import (
	"fmt"
	"io"
	"os"
	"reflect"
	"sort"
	"strings"
	"testing"
)

// platformParam describes one request parameter from platform swagger
type platformParam struct {
	Name string
	// OpenAPI type: integer, string, boolean, number, array, object or empty if unknown
	Type string
	// OpenAPI type of array items, empty if unknown
	Items    string
	Required bool
	// Value of "default" from swagger, nil if not set
	Default interface{}
}

// extractTypeFromSchema extracts non-null type from "type" (string or array), "oneOf"/"anyOf" or "$ref" (object)
func extractTypeFromSchema(schema map[string]interface{}) string {
	switch typ := schema["type"].(type) {
	case string:
		return typ
	case []interface{}:
		for _, item := range typ {
			if s, ok := item.(string); ok && s != "null" {
				return s
			}
		}
	}

	for _, key := range []string{"oneOf", "anyOf"} {
		variants, ok := schema[key].([]interface{})
		if !ok {
			continue
		}
		for _, variant := range variants {
			if variantMap, ok := variant.(map[string]interface{}); ok {
				if variantType := extractTypeFromSchema(variantMap); variantType != "" && variantType != "null" {
					return variantType
				}
			}
		}
	}

	if _, ok := schema["$ref"]; ok {
		return "object"
	}

	return ""
}

// extractItemsType extracts type of array items from schema, including arrays declared inside oneOf/anyOf
func extractItemsType(schema map[string]interface{}) string {
	if items, ok := schema["items"].(map[string]interface{}); ok {
		return extractTypeFromSchema(items)
	}

	for _, key := range []string{"oneOf", "anyOf"} {
		variants, ok := schema[key].([]interface{})
		if !ok {
			continue
		}
		for _, variant := range variants {
			if variantMap, ok := variant.(map[string]interface{}); ok && extractTypeFromSchema(variantMap) == "array" {
				if items := extractItemsType(variantMap); items != "" {
					return items
				}
			}
		}
	}

	return ""
}

// getParameters returns request parameters of all methods, content types and query/path parameters of a path
func getParameters(input map[string]interface{}) []platformParam {
	params := make(map[string]platformParam)
	add := func(name string, schema map[string]interface{}, required bool) {
		p := platformParam{Name: name, Required: required}
		if schema != nil {
			p.Type = extractTypeFromSchema(schema)
			if p.Type == "array" {
				p.Items = extractItemsType(schema)
			}
			p.Default = schema["default"]
		}
		if prev, ok := params[name]; ok {
			p.Required = p.Required || prev.Required
			if p.Type == "" {
				p.Type, p.Items = prev.Type, prev.Items
			}
			if p.Default == nil {
				p.Default = prev.Default
			}
		}
		params[name] = p
	}

	for _, method := range []string{"get", "post", "put", "delete", "patch", "head", "options"} {
		operation, ok := input[method].(map[string]interface{})
		if !ok {
			continue
		}

		if requestBody, ok := operation["requestBody"].(map[string]interface{}); ok {
			content, _ := requestBody["content"].(map[string]interface{})
			for _, media := range content {
				mediaMap, _ := media.(map[string]interface{})
				schema, _ := mediaMap["schema"].(map[string]interface{})
				if schema == nil {
					continue
				}
				requiredFields := make(map[string]bool)
				if req, ok := schema["required"].([]interface{}); ok {
					for _, r := range req {
						if reqStr, ok := r.(string); ok {
							requiredFields[reqStr] = true
						}
					}
				}
				properties, _ := schema["properties"].(map[string]interface{})
				for name, prop := range properties {
					propMap, _ := prop.(map[string]interface{})
					add(name, propMap, requiredFields[name])
				}
			}
		}

		if parameters, ok := operation["parameters"].([]interface{}); ok {
			for _, p := range parameters {
				param, ok := p.(map[string]interface{})
				if !ok {
					continue
				}
				name, ok := param["name"].(string)
				if !ok {
					continue
				}
				schema, _ := param["schema"].(map[string]interface{})
				required, _ := param["required"].(bool)
				add(name, schema, required)
			}
		}
	}

	result := make([]platformParam, 0, len(params))
	for _, p := range params {
		result = append(result, p)
	}
	sort.Slice(result, func(i, j int) bool { return result[i].Name < result[j].Name })

	return result
}

func getBytesFromJSON(fileName string, t *testing.T) []byte {
	jsonFile, err := os.Open(fileName)
	if err != nil {
		t.Error(err)
	}
	defer jsonFile.Close()

	bytes, err := io.ReadAll(jsonFile)
	if err != nil {
		t.Error(err)
	}

	return bytes
}

// getErrorsFromJSON compares platform requests from swagger with the values SDK passes to DecortApiCall*
func getErrorsFromJSON(bytes []byte, t *testing.T, cloud string) {
	var requests map[string]interface{}

	switch cloud {
	case "cloudapi":
		requests = getRequestsMapCloudAPI()
	case "cloudbroker":
		requests = getRequestsMapCloudbroker()
	case "sdn":
		requests = getRequestsMapSDN()
	default:
		t.Fatalf("Wrong cloud provided, expected `cloudapi`, `cloudbroker` or `sdn`, got %s", cloud)
	}

	index, err := getSDKIndex()
	if err != nil {
		t.Fatalf("can not parse SDK sources: %v", err)
	}

	paths, err := getMapFromFile(bytes)
	if err != nil {
		t.Fatal(err)
	}

	requestPaths := make([]string, 0, len(requests))
	for k := range requests {
		requestPaths = append(requestPaths, k)
	}
	sort.Strings(requestPaths)

	var absentOnPlatform, invalidKeys []string
	for _, k := range requestPaths {
		if !strings.HasPrefix(k, "/restmachine/"+cloud+"/") {
			invalidKeys = append(invalidKeys, k)
			continue
		}
		// exclude deprecated urls from analysis
		if !validateUrlFromJson(k) {
			continue
		}
		v, ok := paths[k]
		if !ok {
			absentOnPlatform = append(absentOnPlatform, k)
			continue
		}

		errs := checkPath(k, getParameters(v.(map[string]interface{})), index)
		if len(errs) > 0 {
			t.Errorf("Path %s has following errors: %v", k, errs)
		}
	}

	if len(invalidKeys) > 0 {
		t.Errorf("Request map for %s has keys that don't start with /restmachine/%s/ and are never checked: %v", cloud, cloud, invalidKeys)
	}
	if len(absentOnPlatform) > 0 {
		t.Errorf("Request map has paths that platform doesn't (remove them from request map): %v", absentOnPlatform)
	}
}

// requestVariant is one distinct request SDK sends to a path (e.g. sync and async methods send different wrappers)
type requestVariant struct {
	FuncName  string
	Transport string
	Fields    []sentField
}

// checkPath compares platform parameters of a path with every distinct request SDK sends to this path
func checkPath(path string, params []platformParam, index *sdkIndex) []string {
	calls := index.callsForPath(path)
	if len(calls) == 0 {
		return []string{"SDK call for this path is not found in sources, can not check it"}
	}

	type variantKey struct{ dir, typeName, transport string }
	seen := make(map[variantKey]bool)
	var variants []requestVariant
	var errs []string

	for _, call := range calls {
		key := variantKey{call.Dir, call.TypeName, call.Transport}
		if seen[key] {
			continue
		}
		seen[key] = true

		fields, ok := index.sentFields(call)
		if !ok {
			errs = append(errs, fmt.Sprintf("can not resolve type %s sent by %s", call.TypeName, call.FuncName))
			continue
		}
		variants = append(variants, requestVariant{FuncName: call.FuncName, Transport: call.Transport, Fields: fields})
	}

	return append(errs, compareVariants(params, variants)...)
}

// compareVariants returns differences between platform parameters and all requests SDK sends to the path
func compareVariants(params []platformParam, variants []requestVariant) []string {
	var errs []string
	seenErr := make(map[string]bool)
	add := func(msg string) {
		if !seenErr[msg] {
			seenErr[msg] = true
			errs = append(errs, msg)
		}
	}

	byName := make([]map[string]sentField, len(variants))
	for i, v := range variants {
		byName[i] = make(map[string]sentField, len(v.Fields))
		for _, f := range v.Fields {
			if _, ok := byName[i][f.Name]; ok && v.Transport == transportForm {
				add(fmt.Sprintf("Golang structure sends field %s more than once", f.Name))
			}
			byName[i][f.Name] = f
		}
	}

	paramsByName := make(map[string]bool, len(params))
	for _, p := range params {
		paramsByName[p.Name] = true

		var sentBy, notSentBy []string
		for i, v := range variants {
			f, ok := byName[i][p.Name]
			if !ok {
				notSentBy = append(notSentBy, v.FuncName)
				continue
			}
			sentBy = append(sentBy, v.FuncName)

			if !checkKind(p.Type, p.Items, f, v.Transport) {
				add(fmt.Sprintf("Field %s has different type parameters on the platform (%s) and in golang structure (%s)",
					p.Name, platformTypeString(p), f.Type))
			}
			if msg := checkRequired(p, f); msg != "" {
				add(msg)
			}
		}

		if len(sentBy) == 0 {
			add(fmt.Sprintf("Platform has field %s that golang structure doesn't", p.Name))
			continue
		}
		for _, fn := range notSentBy {
			if p.Required {
				add(fmt.Sprintf("Required field %s is not sent by %s", p.Name, fn))
			} else if p.Type == "boolean" && p.Default == true {
				add(fmt.Sprintf("Field %s is not sent by %s, platform default is true", p.Name, fn))
			}
		}
	}

	for _, v := range variants {
		for _, f := range v.Fields {
			if !paramsByName[f.Name] {
				add(fmt.Sprintf("Golang structure has field %q (%s) that platform doesn't", f.Name, f.GoName))
			}
		}
	}

	return errs
}

func platformTypeString(p platformParam) string {
	if p.Type == "array" && p.Items != "" {
		return "array of " + p.Items
	}
	return p.Type
}

// hasValidateTag checks if `validate` tag contains exactly the given tag
func hasValidateTag(validate, tag string) bool {
	for _, v := range strings.Split(validate, ",") {
		if strings.TrimSpace(v) == tag {
			return true
		}
	}
	return false
}

func isIntKind(k reflect.Kind) bool {
	switch k {
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64,
		reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
		return true
	}
	return false
}

// checkRequired returns description of required mismatch between platform and golang field or empty string
func checkRequired(p platformParam, f sentField) string {
	// validators without omitempty fail on zero value, so such field can not be omitted either
	goRequired := hasValidateTag(f.Validate, "required") ||
		(f.Validate != "" && !hasValidateTag(f.Validate, "omitempty"))

	// numbers and booleans without omitempty are always sent and zero is a meaningful value for them
	alwaysSent := false
	if f.Type != nil && !f.OmitEmpty {
		kind := f.Type.Kind()
		alwaysSent = isIntKind(kind) || kind == reflect.Bool || kind == reflect.Float32 || kind == reflect.Float64
	}

	if p.Required && !goRequired && !alwaysSent {
		return fmt.Sprintf("Field %s is required on the platform but is optional in golang structure", p.Name)
	}
	if !p.Required && hasValidateTag(f.Validate, "required") {
		return fmt.Sprintf("Field %s is optional on the platform but is required in golang structure", p.Name)
	}
	return ""
}

// checkKind checks if type field from platform corresponds to field type in golang structure
func checkKind(platformType, items string, f sentField, transport string) bool {
	typ := f.Type
	// type can not be resolved on one of the sides
	if typ == nil || platformType == "" {
		return true
	}
	for typ.Kind() == reflect.Ptr {
		typ = typ.Elem()
	}

	kind := typ.Kind()
	switch {
	case isIntKind(kind):
		return platformType == "integer"

	case kind == reflect.String:
		if platformType == "string" {
			return true
		}
		// json-encoded object or array of objects
		return transport == transportForm &&
			(platformType == "object" || (platformType == "array" && items == "object"))

	case kind == reflect.Bool:
		return platformType == "boolean"

	case kind == reflect.Float32 || kind == reflect.Float64:
		return platformType == "number"

	case kind == reflect.Interface:
		if hasValidateTag(f.Validate, "isBool") {
			return platformType == "boolean"
		}
		return true

	case kind == reflect.Map || kind == reflect.Struct:
		return platformType == "object"

	case kind == reflect.Array || kind == reflect.Slice:
		if platformType != "array" {
			return false
		}
		elem := typ.Elem()
		for elem.Kind() == reflect.Ptr {
			elem = elem.Elem()
		}
		// items type is not declared on the platform
		if items == "" {
			return true
		}
		switch {
		case elem.Kind() == reflect.String:
			// list of json-encoded objects
			return items == "string" || (transport == transportForm && items == "object")
		case isIntKind(elem.Kind()):
			return items == "integer"
		case elem.Kind() == reflect.Bool:
			return items == "boolean"
		case elem.Kind() == reflect.Float32 || elem.Kind() == reflect.Float64:
			return items == "number"
		case elem.Kind() == reflect.Struct || elem.Kind() == reflect.Map:
			return items == "object"
		default:
			return true
		}
	}

	return true
}