package service

import (
	"context"
	"fmt"
	"net/http"
	"strings"

	"cmr-backend/internal/apperr"
	"cmr-backend/internal/platform/security"
	"cmr-backend/internal/store/postgres"
)

type AdminEventService struct {
	store *postgres.Store
}

type AdminEventSummary struct {
	ID             string                `json:"id"`
	TenantCode     *string               `json:"tenantCode,omitempty"`
	TenantName     *string               `json:"tenantName,omitempty"`
	Slug           string                `json:"slug"`
	DisplayName    string                `json:"displayName"`
	Summary        *string               `json:"summary,omitempty"`
	Status         string                `json:"status"`
	CurrentRelease *AdminEventReleaseRef `json:"currentRelease,omitempty"`
}

type AdminEventReleaseRef struct {
	ID                     string  `json:"id"`
	ConfigLabel            *string `json:"configLabel,omitempty"`
	ManifestURL            *string `json:"manifestUrl,omitempty"`
	ManifestChecksumSha256 *string `json:"manifestChecksumSha256,omitempty"`
	RouteCode              *string `json:"routeCode,omitempty"`
}

type AdminEventDetail struct {
	Event         AdminEventSummary      `json:"event"`
	LatestSource  *EventConfigSourceView `json:"latestSource,omitempty"`
	SourceCount   int                    `json:"sourceCount"`
	CurrentSource *AdminAssembledSource  `json:"currentSource,omitempty"`
}

type CreateAdminEventInput struct {
	TenantCode  *string `json:"tenantCode,omitempty"`
	Slug        string  `json:"slug"`
	DisplayName string  `json:"displayName"`
	Summary     *string `json:"summary,omitempty"`
	Status      string  `json:"status"`
}

type UpdateAdminEventInput struct {
	TenantCode  *string `json:"tenantCode,omitempty"`
	Slug        string  `json:"slug"`
	DisplayName string  `json:"displayName"`
	Summary     *string `json:"summary,omitempty"`
	Status      string  `json:"status"`
}

type SaveAdminEventSourceInput struct {
	Map struct {
		MapID     string `json:"mapId"`
		VersionID string `json:"versionId"`
	} `json:"map"`
	Playfield struct {
		PlayfieldID string `json:"playfieldId"`
		VersionID   string `json:"versionId"`
	} `json:"playfield"`
	ResourcePack *struct {
		ResourcePackID string `json:"resourcePackId"`
		VersionID      string `json:"versionId"`
	} `json:"resourcePack,omitempty"`
	GameModeCode string         `json:"gameModeCode"`
	RouteCode    *string        `json:"routeCode,omitempty"`
	Overrides    map[string]any `json:"overrides,omitempty"`
	Notes        *string        `json:"notes,omitempty"`
}

type AdminAssembledSource struct {
	Refs      map[string]any `json:"refs"`
	Runtime   map[string]any `json:"runtime"`
	Overrides map[string]any `json:"overrides,omitempty"`
}

func NewAdminEventService(store *postgres.Store) *AdminEventService {
	return &AdminEventService{store: store}
}

func (s *AdminEventService) ListEvents(ctx context.Context, limit int) ([]AdminEventSummary, error) {
	items, err := s.store.ListAdminEvents(ctx, limit)
	if err != nil {
		return nil, err
	}
	results := make([]AdminEventSummary, 0, len(items))
	for _, item := range items {
		results = append(results, buildAdminEventSummary(item))
	}
	return results, nil
}

func (s *AdminEventService) CreateEvent(ctx context.Context, input CreateAdminEventInput) (*AdminEventSummary, error) {
	input.Slug = strings.TrimSpace(input.Slug)
	input.DisplayName = strings.TrimSpace(input.DisplayName)
	if input.Slug == "" || input.DisplayName == "" {
		return nil, apperr.New(http.StatusBadRequest, "invalid_params", "slug and displayName are required")
	}

	var tenantID *string
	var tenantCode *string
	var tenantName *string
	if input.TenantCode != nil && strings.TrimSpace(*input.TenantCode) != "" {
		tenant, err := s.store.GetTenantByCode(ctx, strings.TrimSpace(*input.TenantCode))
		if err != nil {
			return nil, err
		}
		if tenant == nil {
			return nil, apperr.New(http.StatusNotFound, "tenant_not_found", "tenant not found")
		}
		tenantID = &tenant.ID
		tenantCode = &tenant.TenantCode
		tenantName = &tenant.Name
	}

	publicID, err := security.GeneratePublicID("evt")
	if err != nil {
		return nil, err
	}

	tx, err := s.store.Begin(ctx)
	if err != nil {
		return nil, err
	}
	defer tx.Rollback(ctx)

	item, err := s.store.CreateAdminEvent(ctx, tx, postgres.CreateAdminEventParams{
		PublicID:    publicID,
		TenantID:    tenantID,
		Slug:        input.Slug,
		DisplayName: input.DisplayName,
		Summary:     trimStringPtr(input.Summary),
		Status:      normalizeEventCatalogStatus(input.Status),
	})
	if err != nil {
		return nil, err
	}
	if err := tx.Commit(ctx); err != nil {
		return nil, err
	}

	return &AdminEventSummary{
		ID:          item.PublicID,
		TenantCode:  tenantCode,
		TenantName:  tenantName,
		Slug:        item.Slug,
		DisplayName: item.DisplayName,
		Summary:     item.Summary,
		Status:      item.Status,
	}, nil
}

func (s *AdminEventService) UpdateEvent(ctx context.Context, eventPublicID string, input UpdateAdminEventInput) (*AdminEventSummary, error) {
	record, err := s.store.GetAdminEventByPublicID(ctx, strings.TrimSpace(eventPublicID))
	if err != nil {
		return nil, err
	}
	if record == nil {
		return nil, apperr.New(http.StatusNotFound, "event_not_found", "event not found")
	}

	input.Slug = strings.TrimSpace(input.Slug)
	input.DisplayName = strings.TrimSpace(input.DisplayName)
	if input.Slug == "" || input.DisplayName == "" {
		return nil, apperr.New(http.StatusBadRequest, "invalid_params", "slug and displayName are required")
	}

	var tenantID *string
	clearTenant := false
	if input.TenantCode != nil {
		if trimmed := strings.TrimSpace(*input.TenantCode); trimmed != "" {
			tenant, err := s.store.GetTenantByCode(ctx, trimmed)
			if err != nil {
				return nil, err
			}
			if tenant == nil {
				return nil, apperr.New(http.StatusNotFound, "tenant_not_found", "tenant not found")
			}
			tenantID = &tenant.ID
		} else {
			clearTenant = true
		}
	}

	tx, err := s.store.Begin(ctx)
	if err != nil {
		return nil, err
	}
	defer tx.Rollback(ctx)

	updated, err := s.store.UpdateAdminEvent(ctx, tx, postgres.UpdateAdminEventParams{
		EventID:     record.ID,
		TenantID:    tenantID,
		Slug:        input.Slug,
		DisplayName: input.DisplayName,
		Summary:     trimStringPtr(input.Summary),
		Status:      normalizeEventCatalogStatus(input.Status),
		ClearTenant: clearTenant,
	})
	if err != nil {
		return nil, err
	}
	if err := tx.Commit(ctx); err != nil {
		return nil, err
	}

	refreshed, err := s.store.GetAdminEventByPublicID(ctx, updated.PublicID)
	if err != nil {
		return nil, err
	}
	if refreshed == nil {
		return nil, apperr.New(http.StatusNotFound, "event_not_found", "event not found")
	}
	summary := buildAdminEventSummary(*refreshed)
	return &summary, nil
}

func (s *AdminEventService) GetEventDetail(ctx context.Context, eventPublicID string) (*AdminEventDetail, error) {
	record, err := s.store.GetAdminEventByPublicID(ctx, strings.TrimSpace(eventPublicID))
	if err != nil {
		return nil, err
	}
	if record == nil {
		return nil, apperr.New(http.StatusNotFound, "event_not_found", "event not found")
	}

	sources, err := s.store.ListEventConfigSourcesByEventID(ctx, record.ID, 1)
	if err != nil {
		return nil, err
	}
	allSources, err := s.store.ListEventConfigSourcesByEventID(ctx, record.ID, 200)
	if err != nil {
		return nil, err
	}

	result := &AdminEventDetail{
		Event:       buildAdminEventSummary(*record),
		SourceCount: len(allSources),
	}
	if len(sources) > 0 {
		latest, err := buildEventConfigSourceView(&sources[0], record.PublicID)
		if err != nil {
			return nil, err
		}
		result.LatestSource = latest
		result.CurrentSource = buildAdminAssembledSource(latest.Source)
	}
	return result, nil
}

func (s *AdminEventService) SaveEventSource(ctx context.Context, eventPublicID string, input SaveAdminEventSourceInput) (*EventConfigSourceView, error) {
	eventRecord, err := s.store.GetAdminEventByPublicID(ctx, strings.TrimSpace(eventPublicID))
	if err != nil {
		return nil, err
	}
	if eventRecord == nil {
		return nil, apperr.New(http.StatusNotFound, "event_not_found", "event not found")
	}

	input.GameModeCode = strings.TrimSpace(input.GameModeCode)
	input.Map.MapID = strings.TrimSpace(input.Map.MapID)
	input.Map.VersionID = strings.TrimSpace(input.Map.VersionID)
	input.Playfield.PlayfieldID = strings.TrimSpace(input.Playfield.PlayfieldID)
	input.Playfield.VersionID = strings.TrimSpace(input.Playfield.VersionID)
	if input.Map.MapID == "" || input.Map.VersionID == "" || input.Playfield.PlayfieldID == "" || input.Playfield.VersionID == "" || input.GameModeCode == "" {
		return nil, apperr.New(http.StatusBadRequest, "invalid_params", "map, playfield and gameModeCode are required")
	}

	mapVersion, err := s.store.GetResourceMapVersionByPublicID(ctx, input.Map.MapID, input.Map.VersionID)
	if err != nil {
		return nil, err
	}
	if mapVersion == nil {
		return nil, apperr.New(http.StatusNotFound, "map_version_not_found", "map version not found")
	}
	playfieldVersion, err := s.store.GetResourcePlayfieldVersionByPublicID(ctx, input.Playfield.PlayfieldID, input.Playfield.VersionID)
	if err != nil {
		return nil, err
	}
	if playfieldVersion == nil {
		return nil, apperr.New(http.StatusNotFound, "playfield_version_not_found", "playfield version not found")
	}

	var resourcePackVersion *postgres.ResourcePackVersion
	if input.ResourcePack != nil {
		input.ResourcePack.ResourcePackID = strings.TrimSpace(input.ResourcePack.ResourcePackID)
		input.ResourcePack.VersionID = strings.TrimSpace(input.ResourcePack.VersionID)
		if input.ResourcePack.ResourcePackID == "" || input.ResourcePack.VersionID == "" {
			return nil, apperr.New(http.StatusBadRequest, "invalid_params", "resourcePackId and versionId are required when resourcePack is provided")
		}
		resourcePackVersion, err = s.store.GetResourcePackVersionByPublicID(ctx, input.ResourcePack.ResourcePackID, input.ResourcePack.VersionID)
		if err != nil {
			return nil, err
		}
		if resourcePackVersion == nil {
			return nil, apperr.New(http.StatusNotFound, "resource_pack_version_not_found", "resource pack version not found")
		}
	}

	source := s.buildEventSource(eventRecord, mapVersion, playfieldVersion, resourcePackVersion, input)
	if err := validateSourceConfig(source); err != nil {
		return nil, err
	}

	nextVersion, err := s.store.NextEventConfigSourceVersion(ctx, eventRecord.ID)
	if err != nil {
		return nil, err
	}

	note := trimStringPtr(input.Notes)
	if note == nil {
		defaultNote := fmt.Sprintf("assembled from admin refs: map=%s/%s playfield=%s/%s", input.Map.MapID, input.Map.VersionID, input.Playfield.PlayfieldID, input.Playfield.VersionID)
		note = &defaultNote
	}

	tx, err := s.store.Begin(ctx)
	if err != nil {
		return nil, err
	}
	defer tx.Rollback(ctx)

	record, err := s.store.UpsertEventConfigSource(ctx, tx, postgres.UpsertEventConfigSourceParams{
		EventID:         eventRecord.ID,
		SourceVersionNo: nextVersion,
		SourceKind:      "admin_assembled_bundle",
		SchemaID:        "event-source",
		SchemaVersion:   resolveSchemaVersion(source),
		Status:          "active",
		Source:          source,
		Notes:           note,
	})
	if err != nil {
		return nil, err
	}
	if err := tx.Commit(ctx); err != nil {
		return nil, err
	}
	return buildEventConfigSourceView(record, eventRecord.PublicID)
}

func (s *AdminEventService) buildEventSource(event *postgres.AdminEventRecord, mapVersion *postgres.ResourceMapVersion, playfieldVersion *postgres.ResourcePlayfieldVersion, resourcePackVersion *postgres.ResourcePackVersion, input SaveAdminEventSourceInput) map[string]any {
	source := map[string]any{
		"schemaVersion": "1",
		"app": map[string]any{
			"id":    event.PublicID,
			"title": event.DisplayName,
		},
		"refs": map[string]any{
			"map": map[string]any{
				"id":        input.Map.MapID,
				"versionId": input.Map.VersionID,
			},
			"playfield": map[string]any{
				"id":        input.Playfield.PlayfieldID,
				"versionId": input.Playfield.VersionID,
			},
			"gameMode": map[string]any{
				"code": input.GameModeCode,
			},
		},
		"map": map[string]any{
			"tiles":   mapVersion.TilesRootURL,
			"mapmeta": mapVersion.MapmetaURL,
		},
		"playfield": map[string]any{
			"kind": "course",
			"source": map[string]any{
				"type": playfieldVersion.SourceType,
				"url":  playfieldVersion.SourceURL,
			},
		},
		"game": map[string]any{
			"mode": input.GameModeCode,
		},
	}
	if event.Summary != nil && strings.TrimSpace(*event.Summary) != "" {
		source["summary"] = *event.Summary
	}
	if event.TenantCode != nil && strings.TrimSpace(*event.TenantCode) != "" {
		source["branding"] = map[string]any{
			"tenantCode": *event.TenantCode,
		}
	}
	if input.RouteCode != nil && strings.TrimSpace(*input.RouteCode) != "" {
		source["playfield"].(map[string]any)["metadata"] = map[string]any{
			"routeCode": strings.TrimSpace(*input.RouteCode),
		}
	}
	if resourcePackVersion != nil {
		source["refs"].(map[string]any)["resourcePack"] = map[string]any{
			"id":        input.ResourcePack.ResourcePackID,
			"versionId": input.ResourcePack.VersionID,
		}
		resources := map[string]any{}
		assets := map[string]any{}
		if resourcePackVersion.ThemeProfileCode != nil && strings.TrimSpace(*resourcePackVersion.ThemeProfileCode) != "" {
			resources["themeProfile"] = *resourcePackVersion.ThemeProfileCode
		}
		if resourcePackVersion.ContentEntryURL != nil && strings.TrimSpace(*resourcePackVersion.ContentEntryURL) != "" {
			assets["contentHtml"] = *resourcePackVersion.ContentEntryURL
		}
		if resourcePackVersion.AudioRootURL != nil && strings.TrimSpace(*resourcePackVersion.AudioRootURL) != "" {
			resources["audioRoot"] = *resourcePackVersion.AudioRootURL
		}
		if len(resources) > 0 {
			source["resources"] = resources
		}
		if len(assets) > 0 {
			source["assets"] = assets
		}
	}
	if len(input.Overrides) > 0 {
		source["overrides"] = input.Overrides
		mergeJSONObject(source, input.Overrides)
	}
	return source
}

func buildAdminEventSummary(item postgres.AdminEventRecord) AdminEventSummary {
	summary := AdminEventSummary{
		ID:          item.PublicID,
		TenantCode:  item.TenantCode,
		TenantName:  item.TenantName,
		Slug:        item.Slug,
		DisplayName: item.DisplayName,
		Summary:     item.Summary,
		Status:      item.Status,
	}
	if item.CurrentReleasePubID != nil {
		summary.CurrentRelease = &AdminEventReleaseRef{
			ID:                     *item.CurrentReleasePubID,
			ConfigLabel:            item.ConfigLabel,
			ManifestURL:            item.ManifestURL,
			ManifestChecksumSha256: item.ManifestChecksum,
			RouteCode:              item.RouteCode,
		}
	}
	return summary
}

func buildAdminAssembledSource(source map[string]any) *AdminAssembledSource {
	result := &AdminAssembledSource{}
	if refs, ok := source["refs"].(map[string]any); ok {
		result.Refs = refs
	}
	runtime := cloneJSONObject(source)
	delete(runtime, "refs")
	delete(runtime, "overrides")
	if overrides, ok := source["overrides"].(map[string]any); ok && len(overrides) > 0 {
		result.Overrides = overrides
	}
	result.Runtime = runtime
	return result
}

func normalizeEventCatalogStatus(value string) string {
	switch strings.TrimSpace(value) {
	case "active":
		return "active"
	case "disabled":
		return "disabled"
	case "archived":
		return "archived"
	default:
		return "draft"
	}
}

func mergeJSONObject(target map[string]any, overrides map[string]any) {
	for key, value := range overrides {
		if valueMap, ok := value.(map[string]any); ok {
			existing, ok := target[key].(map[string]any)
			if !ok {
				existing = map[string]any{}
				target[key] = existing
			}
			mergeJSONObject(existing, valueMap)
			continue
		}
		target[key] = value
	}
}