package handler

import (
	"baron-sso-backend/internal/domain"
	"encoding/json"
	"errors"
	"sort"
	"strings"

	"github.com/gofiber/fiber/v2"
)

const (
	clientTenantAccessRestrictedKey = "tenant_access_restricted"
	clientAllowedTenantsKey         = "allowed_tenants"
)

func normalizeClientTenantAccessMetadata(metadata map[string]interface{}) (map[string]interface{}, error) {
	if metadata == nil {
		metadata = map[string]interface{}{}
	}

	restricted := readMetadataBoolValue(metadata, clientTenantAccessRestrictedKey)
	allowedTenants := normalizeMetadataStringSlice(metadata[clientAllowedTenantsKey])
	ownerTenantID := normalizeMetadataString(metadata["tenant_id"])

	if len(allowedTenants) > 0 {
		restricted = true
	}

	if !restricted {
		delete(metadata, clientAllowedTenantsKey)
		metadata[clientTenantAccessRestrictedKey] = false
		return metadata, nil
	}

	if ownerTenantID != "" {
		allowedTenants = append(allowedTenants, ownerTenantID)
	}
	allowedTenants = uniqueSortedStrings(allowedTenants)
	if len(allowedTenants) == 0 {
		return nil, errors.New("allowed_tenants is required when tenant_access_restricted is enabled")
	}

	metadata[clientTenantAccessRestrictedKey] = true
	metadata[clientAllowedTenantsKey] = allowedTenants
	return metadata, nil
}

func clientTenantAccessRestricted(metadata map[string]interface{}) bool {
	if metadata == nil {
		return false
	}
	if readMetadataBoolValue(metadata, clientTenantAccessRestrictedKey) {
		return true
	}
	return len(normalizeMetadataStringSlice(metadata[clientAllowedTenantsKey])) > 0
}

func clientAllowedTenants(metadata map[string]interface{}) []string {
	if metadata == nil {
		return nil
	}
	if !clientTenantAccessRestricted(metadata) {
		return nil
	}
	return uniqueSortedStrings(normalizeMetadataStringSlice(metadata[clientAllowedTenantsKey]))
}

func normalizeMetadataStringSlice(raw any) []string {
	switch value := raw.(type) {
	case []string:
		return uniqueSortedStrings(value)
	case []any:
		items := make([]string, 0, len(value))
		for _, item := range value {
			if s, ok := item.(string); ok {
				items = append(items, s)
			}
		}
		return uniqueSortedStrings(items)
	default:
		return nil
	}
}

func normalizeMetadataString(raw any) string {
	s, ok := raw.(string)
	if !ok {
		return ""
	}
	return strings.TrimSpace(s)
}

func uniqueSortedStrings(values []string) []string {
	if len(values) == 0 {
		return nil
	}
	seen := make(map[string]struct{}, len(values))
	out := make([]string, 0, len(values))
	for _, value := range values {
		trimmed := strings.TrimSpace(value)
		if trimmed == "" {
			continue
		}
		if _, ok := seen[trimmed]; ok {
			continue
		}
		seen[trimmed] = struct{}{}
		out = append(out, trimmed)
	}
	sort.Strings(out)
	return out
}

func clientTenantAccessAllowed(profile *domain.UserProfileResponse, client domain.HydraClient) bool {
	if !clientTenantAccessRestricted(client.Metadata) {
		return true
	}
	allowed := clientAllowedTenants(client.Metadata)
	if len(allowed) == 0 {
		return false
	}
	keys := manageableTenantKeysFromProfile(profile)
	if len(keys) == 0 {
		return false
	}
	for _, tenantID := range allowed {
		if _, ok := keys[strings.ToLower(strings.TrimSpace(tenantID))]; ok {
			return true
		}
	}
	return false
}

func tenantNotAllowedError(c *fiber.Ctx) error {
	return errorJSONCode(c, fiber.StatusForbidden, "tenant_not_allowed", "허용되지 않은 테넌트입니다.")
}

func isClientTenantAccessAllowed(profile *domain.UserProfileResponse, client domain.HydraClient) bool {
	if profile == nil {
		return false
	}
	return clientTenantAccessAllowed(profile, client)
}

func enforceClientTenantAccess(c *fiber.Ctx, client domain.HydraClient, profile *domain.UserProfileResponse, resolveErr error) error {
	if !clientTenantAccessRestricted(client.Metadata) {
		return nil
	}
	if resolveErr != nil || profile == nil {
		return tenantNotAllowedError(c)
	}
	if !clientTenantAccessAllowed(profile, client) {
		return tenantNotAllowedError(c)
	}
	return nil
}

type clientStructuredScope struct {
	Name      string `json:"name"`
	Mandatory bool   `json:"mandatory"`
	Locked    bool   `json:"locked"`
}

func mergeRequestedScopesWithClientRequirements(client domain.HydraClient, requested []string) []string {
	combined := make([]string, 0, len(requested)+2)
	combined = append(combined, requested...)
	combined = append(combined, requiredClientScopes(client)...)

	return normalizeScopesInConsentOrder(combined)
}

func normalizeScopesInConsentOrder(scopes []string) []string {
	combined := make([]string, 0, len(scopes))
	combined = append(combined, scopes...)

	seen := make(map[string]struct{}, len(combined))
	out := make([]string, 0, len(combined))

	appendIfPresent := func(scope string) {
		scope = strings.TrimSpace(scope)
		if scope == "" {
			return
		}
		if _, ok := seen[scope]; ok {
			return
		}
		for _, candidate := range combined {
			if strings.TrimSpace(candidate) != scope {
				continue
			}
			seen[scope] = struct{}{}
			out = append(out, scope)
			return
		}
	}

	appendIfPresent("openid")
	appendIfPresent("tenant")

	for _, scope := range combined {
		scope = strings.TrimSpace(scope)
		if scope == "" {
			continue
		}
		if _, ok := seen[scope]; ok {
			continue
		}
		seen[scope] = struct{}{}
		out = append(out, scope)
	}

	return out
}

func requiredClientScopes(client domain.HydraClient) []string {
	required := make([]string, 0, 4)
	if clientTenantAccessRestricted(client.Metadata) {
		required = append(required, "tenant")
	}

	if client.Metadata == nil {
		return normalizeScopesInConsentOrder(required)
	}

	rawStructuredScopes, ok := client.Metadata["structured_scopes"]
	if !ok || rawStructuredScopes == nil {
		return normalizeScopesInConsentOrder(required)
	}

	rawBytes, err := json.Marshal(rawStructuredScopes)
	if err != nil {
		return normalizeScopesInConsentOrder(required)
	}

	var scopes []clientStructuredScope
	if err := json.Unmarshal(rawBytes, &scopes); err != nil {
		return normalizeScopesInConsentOrder(required)
	}

	for _, scope := range scopes {
		name := strings.TrimSpace(scope.Name)
		if name == "" {
			continue
		}
		if scope.Mandatory || scope.Locked {
			required = append(required, name)
		}
	}

	return normalizeScopesInConsentOrder(required)
}