package jobs

import (
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"log"
	"math"
	"net/http"
	"net/url"
	"strings"
	"time"

	"git.nianxx.cn/wangxuming/NianAIGC/backend/internal/prompt"
	"git.nianxx.cn/wangxuming/NianAIGC/backend/internal/providers"
)

type ProviderRegistry map[string]providers.Adapter

type ProviderResolver interface {
	Resolve(context.Context, string) (providers.Adapter, error)
}

type ProviderAssetURLResolver interface {
	ResolveProviderAssetURL(context.Context, string, string, time.Duration) (sourceURL string, accessURL string, err error)
}

func (registry ProviderRegistry) Resolve(_ context.Context, name string) (providers.Adapter, error) {
	return registry[name], nil
}

type ProviderProcessor struct {
	Providers   ProviderResolver
	Store       Store
	AssetURLs   ProviderAssetURLResolver
	AssetURLTTL time.Duration
}

func (p ProviderProcessor) Advance(ctx context.Context, job Job) (Job, error) {
	// A persisted terminal provider result is the recovery checkpoint. Replaying
	// it must run downstream idempotent finalizers, never submit/query again.
	if job.Status.Terminal() {
		return job, nil
	}
	if p.Providers == nil {
		return Job{}, fmt.Errorf("generation provider %q is unavailable", job.Provider)
	}
	adapter, err := p.Providers.Resolve(ctx, job.Provider)
	if err != nil {
		return Job{}, fmt.Errorf("resolve generation provider %q: %w", job.Provider, err)
	}
	if adapter == nil {
		return Job{}, fmt.Errorf("generation provider %q is unavailable", job.Provider)
	}
	var request providers.Request
	if err := json.Unmarshal(job.RequestPayload, &request); err != nil {
		return Job{}, errors.New("invalid provider request payload")
	}
	if job.ProviderTaskID == "" && job.ProviderDispatchStartedAt == nil {
		request, err = p.refreshAssetURLs(ctx, job, request)
		if err != nil {
			return Job{}, fmt.Errorf("prepare provider asset URLs: %w", err)
		}
	}
	var result providers.Result
	phase := "submit"
	expectedStatus := job.Status
	if job.ProviderTaskID == "" {
		if job.ProviderDispatchStartedAt != nil {
			logProviderFailureDiagnostic(providerFailureDiagnostic{
				JobID:      safeProviderLogToken(job.ID),
				Provider:   safeProviderLogToken(job.Provider),
				Phase:      "submit",
				ErrorClass: "unknown_outcome",
			})
			failed := StatusFailed
			failure := &JobError{Message: unknownProviderSubmissionMessage, Retryable: false}
			if p.Store == nil {
				job.Status, job.Error = failed, failure
				return job, nil
			}
			return p.Store.UpdateJob(ctx, job.ID, workerPatch(job, Patch{Status: &failed, Error: failure}))
		}
		if p.Store != nil {
			started := time.Now().UTC()
			prepared, persistErr := p.Store.UpdateJob(ctx, job.ID, workerPatch(job, Patch{ProviderDispatchStartedAt: &started}))
			if persistErr != nil {
				return Job{}, persistErr
			}
			job = prepared
		}
		result, err = adapter.Submit(ctx, request)
	} else {
		phase = "query"
		if modeled, ok := adapter.(providers.ModelQueryAdapter); ok {
			result, err = modeled.QueryModel(ctx, job.ProviderTaskID, job.ReqKey)
		} else {
			result, err = adapter.Query(ctx, job.ProviderTaskID)
		}
	}
	if err != nil {
		logProviderFailure(job, phase, err)
	}
	if err != nil {
		failed := StatusFailed
		failure := providerSubmissionFailure(err)
		if phase == "query" {
			failure = providerQueryFailure(job.Provider, err)
		}
		patch := Patch{Status: &failed, Error: failure}
		var providerError *providers.ProviderError
		if errors.As(err, &providerError) {
			if phase == "submit" && providerError.Status > 0 {
				failure.Message = providers.FailureMessage(job.Provider, providerError.Status, providerError.Code)
			}
			failure.Code = safeFailureToken(providerError.Code, 128)
			patch.ResponsePayload = providerFailurePayload(job, phase, providerError.Status, providerError.Code, providerError.RequestID, providerError.Detail)
			patch.SetResponsePayload = true
		}
		if p.Store == nil {
			job.Status, job.Error = failed, failure
			if patch.SetResponsePayload {
				job.ResponsePayload = patch.ResponsePayload
			}
			return job, nil
		}
		return p.Store.UpdateJob(ctx, job.ID, workerPatch(job, patch))
	}
	if result.TaskID == "" {
		result.TaskID = job.ProviderTaskID
	}
	job.ProviderTaskID = result.TaskID
	terminalFailure := result.Status == providers.StatusFailed || result.Status == providers.StatusCancelled || result.Status == providers.StatusExpired
	if terminalFailure {
		detail := result.ErrorDetail
		if detail == "" {
			detail = result.ErrorMessage
		}
		job.Error = &JobError{Code: safeFailureToken(result.ErrorCode, 128), Message: providers.FailureMessage(job.Provider, 0, result.ErrorCode)}
		if result.ErrorCode == "" && result.Status == providers.StatusCancelled {
			job.Error.Message = "服务商已取消本次生成任务，请确认后重新创建任务。"
		} else if result.ErrorCode == "" && result.Status == providers.StatusExpired {
			job.Error.Message = "服务商生成任务已过期，请确认任务状态后重新创建。"
		}
		// Failed raw responses may echo prompts, signed asset URLs or credentials.
		// Persist only the user explanation and bounded, redacted diagnostics.
		job.ResponsePayload = providerFailurePayload(job, phase, 0, result.ErrorCode, result.RequestID, detail)
		job.Status = Status(result.Status)
		if p.Store == nil {
			return job, nil
		}
		patch := workerPatch(job, Patch{
			Status: &job.Status, ProviderTaskID: &job.ProviderTaskID, Error: job.Error,
			ResponsePayload: job.ResponsePayload, SetResponsePayload: true,
		})
		patch.ExpectedStatuses = []Status{expectedStatus}
		return p.Store.UpdateJob(ctx, job.ID, patch)
	}
	encoded, err := providers.EncodeResult(result)
	if err != nil {
		return Job{}, errors.New("encode provider result")
	}
	if result.Status == providers.StatusSucceeded && len(result.OutputURLs) == 0 {
		failed := StatusFailed
		failure := &JobError{Message: "服务商返回的生成结果缺少可下载文件，请联系管理员核查。", Retryable: false}
		encoded = providerFailurePayload(job, phase, 0, "", result.RequestID, "服务商返回成功状态，但没有可下载文件。")
		if p.Store == nil {
			job.Status, job.Error, job.ResponsePayload = failed, failure, encoded
			return job, nil
		}
		patch := workerPatch(job, Patch{
			Status:             &failed,
			Error:              failure,
			ResponsePayload:    encoded,
			SetResponsePayload: true,
		})
		if result.TaskID != "" {
			patch.ProviderTaskID = &result.TaskID
		}
		return p.Store.UpdateJob(ctx, job.ID, patch)
	}
	job.ResponsePayload = encoded
	job.Status = Status(result.Status)
	job.Error = nil
	if p.Store != nil {
		patch := Patch{Status: &job.Status, ProviderTaskID: &job.ProviderTaskID, ResponsePayload: job.ResponsePayload, SetResponsePayload: true, ClearError: true}
		patch.ExpectedStatuses = []Status{expectedStatus}
		if job.LockedBy != "" {
			worker := job.LockedBy
			patch.ExpectedLockedBy = &worker
		}
		if job.Error != nil {
			patch.Error = job.Error
		}
		return p.Store.UpdateJob(ctx, job.ID, patch)
	}
	return job, nil
}

const (
	unknownProviderSubmissionMessage = "暂时无法确认服务商是否已接收本次请求，为避免重复生成和扣费，平台已停止自动重试。请联系管理员核查任务状态。"
)

func providerSubmissionFailure(err error) *JobError {
	message := unknownProviderSubmissionMessage
	var providerError *providers.ProviderError
	if errors.As(err, &providerError) {
		if providerError.Status > 0 {
			provider := strings.SplitN(providerError.Operation, " ", 2)[0]
			if provider == "volcengine" {
				provider = "volcengine-visual"
			}
			message = providers.FailureMessage(provider, providerError.Status, providerError.Code)
		}
	}
	return &JobError{Message: message, Retryable: false}
}

func providerQueryFailure(provider string, err error) *JobError {
	failure := &JobError{Message: "暂时无法获取服务商的生成结果，请联系管理员核查任务状态。", Retryable: true}
	var upstream *providers.ProviderError
	if errors.As(err, &upstream) && upstream.Status > 0 {
		failure.Code = safeFailureToken(upstream.Code, 128)
		failure.Message = providers.FailureMessage(provider, upstream.Status, upstream.Code)
		failure.Retryable = upstream.Status == http.StatusRequestTimeout || upstream.Status == http.StatusTooManyRequests || upstream.Status >= 500
	}
	return failure
}

func providerFailurePayload(job Job, phase string, status int, code, requestID, detail string) json.RawMessage {
	payload, _ := json.Marshal(map[string]any{"providerError": map[string]any{
		"phase": phase, "status": status, "code": safeFailureToken(code, 128),
		"requestId": safeFailureToken(requestID, 128),
		"detail":    providers.SanitizeFailureDetail(detail, job.RequestPayload),
	}})
	return payload
}

func safeFailureToken(value string, maximum int) string {
	value = strings.TrimSpace(value)
	if len(value) > maximum {
		return ""
	}
	for _, char := range value {
		if (char >= 'a' && char <= 'z') || (char >= 'A' && char <= 'Z') || (char >= '0' && char <= '9') || strings.ContainsRune("-_.:", char) {
			continue
		}
		return ""
	}
	return value
}

type providerFailureDiagnostic struct {
	JobID      string
	Provider   string
	Phase      string
	Status     int
	ErrorClass string
}

func logProviderFailure(job Job, phase string, err error) {
	diagnostic := providerFailureDiagnostic{
		JobID:      safeProviderLogToken(job.ID),
		Provider:   safeProviderLogToken(job.Provider),
		Phase:      safeProviderPhase(phase),
		ErrorClass: "provider",
	}
	if errors.Is(err, context.Canceled) {
		diagnostic.ErrorClass = "canceled"
	} else if errors.Is(err, context.DeadlineExceeded) {
		diagnostic.ErrorClass = "timeout"
	} else {
		var providerError *providers.ProviderError
		if errors.As(err, &providerError) {
			diagnostic.Status = providerError.Status
			if providerError.Status > 0 {
				diagnostic.ErrorClass = "service"
			}
		}
	}
	logProviderFailureDiagnostic(diagnostic)
}

func logProviderFailureDiagnostic(diagnostic providerFailureDiagnostic) {
	log.Printf(
		"zhinian-api generation provider failed jobId=%s provider=%s phase=%s status=%d errorClass=%s",
		diagnostic.JobID,
		diagnostic.Provider,
		diagnostic.Phase,
		diagnostic.Status,
		diagnostic.ErrorClass,
	)
}

func safeProviderPhase(phase string) string {
	if phase == "query" {
		return "query"
	}
	return "submit"
}

func safeProviderLogToken(value string) string {
	value = strings.TrimSpace(value)
	if len(value) == 0 || len(value) > 96 {
		return "invalid"
	}
	for _, character := range value {
		if (character >= 'a' && character <= 'z') || (character >= 'A' && character <= 'Z') || (character >= '0' && character <= '9') || strings.ContainsRune("-_.:", character) {
			continue
		}
		return "invalid"
	}
	return value
}

func (p ProviderProcessor) refreshAssetURLs(ctx context.Context, job Job, request providers.Request) (providers.Request, error) {
	if p.AssetURLs == nil || len(job.InputAssetIDs) == 0 {
		return request, nil
	}
	ttl := p.AssetURLTTL
	if ttl <= 0 {
		ttl = time.Hour
	}
	replacements := make(map[string]string, len(job.InputAssetIDs))
	seen := make(map[string]struct{}, len(job.InputAssetIDs))
	for _, assetID := range job.InputAssetIDs {
		assetID = strings.TrimSpace(assetID)
		if assetID == "" {
			continue
		}
		if _, ok := seen[assetID]; ok {
			continue
		}
		seen[assetID] = struct{}{}
		sourceURL, accessURL, err := p.AssetURLs.ResolveProviderAssetURL(ctx, job.OwnerID, assetID, ttl)
		if err != nil {
			return providers.Request{}, err
		}
		if strings.TrimSpace(sourceURL) == "" || strings.TrimSpace(accessURL) == "" {
			return providers.Request{}, errors.New("provider asset URL is unavailable")
		}
		replacements[sourceURL] = accessURL
	}
	for index, inputURL := range request.InputURLs {
		if accessURL, ok := replacements[inputURL]; ok {
			request.InputURLs[index] = accessURL
		}
	}
	for index := range request.Materials {
		if accessURL, ok := replacements[request.Materials[index].URL]; ok {
			request.Materials[index].URL = accessURL
		}
	}
	return request, nil
}

type ProviderJobBuilder struct {
	ImageProvider, VideoProvider string
	ImageModel, VideoModel       string
	ImageEngine, VideoEngine     string
	ImageEngines                 map[string]ProviderTarget
	ImageModels                  map[string]ProviderTarget
	VideoEngines                 map[string]ProviderTarget
	VideoModels                  map[string]ProviderTarget
	UnavailableProviders         map[string]string
	NewID                        func() string
}

// ProviderTarget is server-owned routing configuration for one UI engine.
// The request may select a known engine and an allow-listed model, but it
// cannot supply an arbitrary provider or model identifier.
type ProviderTarget struct {
	Provider string
	Model    string
	Settings map[string]any
}

func (b ProviderJobBuilder) Build(_ context.Context, owner, client, capability, idempotency string, body map[string]any) (CreateCommand, error) {
	if capability != "image.generate" && capability != "video.generate" {
		return CreateCommand{}, &Error{Kind: ErrorInvalid, Status: 400, Message: "Unsupported capability: " + capability}
	}
	target, engine, err := b.target(capability, body["engine"], body["model"])
	if err != nil {
		return CreateCommand{}, err
	}
	if message := strings.TrimSpace(b.UnavailableProviders[target.Provider]); message != "" {
		return CreateCommand{}, &Error{Kind: ErrorUnavailable, Status: 503, Message: message}
	}
	if target.Provider == "" || target.Model == "" || b.NewID == nil {
		return CreateCommand{}, errors.New("provider job builder is not configured")
	}
	prepared, err := prepareProviderRequest(capability, engine, target.Model, target.Settings, body)
	if err != nil {
		return CreateCommand{}, err
	}
	prepared.request.Model = target.Model
	raw, err := json.Marshal(prepared.request)
	if err != nil {
		return CreateCommand{}, errors.New("encode provider request")
	}
	priority := NormalizePriority(intFromAny(body["priority"]))
	webhook, _ := body["webhookUrl"].(string)
	webhook = strings.TrimSpace(webhook)
	if client != "" && webhook != "" && !validWebhookURL(webhook) {
		return CreateCommand{}, invalidPreparation("webhookUrl must be an HTTP or HTTPS URL")
	}
	return CreateCommand{Job: Job{ID: b.NewID(), OwnerID: owner, ExternalClientID: client, Capability: capability, Provider: target.Provider, ReqKey: target.Model, Status: StatusQueued, Prompt: prepared.request.Prompt, InputURLs: prepared.request.InputURLs, InputAssetIDs: prepared.assetIDs, OutputAssetIDs: []string{}, RequestPayload: raw, IdempotencyKey: idempotency, Priority: priority, WebhookURL: webhook}, IdempotencyBody: body}, nil
}

func validWebhookURL(value string) bool {
	parsed, err := url.Parse(value)
	return err == nil && parsed.IsAbs() && parsed.Host != "" && parsed.User == nil && (parsed.Scheme == "http" || parsed.Scheme == "https")
}

func (b ProviderJobBuilder) target(capability string, rawEngine, rawModel any) (ProviderTarget, string, error) {
	engine := engineName(rawEngine)
	if capability == "image.generate" {
		if rawEngine != nil && engine == "" {
			return ProviderTarget{}, "", invalidPreparation("unsupported image engine")
		}
		configured := firstConfiguredEngine(b.ImageEngine, b.ImageProvider, "image")
		if rawModel != nil {
			if engine == "" {
				engine = configured
			}
			model := stringValue(rawModel)
			if model == "" || engine != "evolink" {
				return ProviderTarget{}, "", invalidPreparation("unsupported image model")
			}
			target, ok := b.ImageModels[model]
			if !ok || target.Provider != "evolink" || target.Model == "" {
				return ProviderTarget{}, "", invalidPreparation("unsupported image model")
			}
			return target, engine, nil
		}
		if engine != "" {
			if engine != "jimeng" && engine != "evolink" && engine != "bailian" && engine != "seedream" {
				return ProviderTarget{}, "", invalidPreparation("unsupported image engine")
			}
			target, ok := b.ImageEngines[engine]
			if !ok || target.Provider == "" || target.Model == "" {
				return ProviderTarget{}, "", errors.New("provider job builder is not configured")
			}
			return target, engine, nil
		}
		if target, ok := b.ImageEngines[configured]; ok && target.Provider == b.ImageProvider && target.Model == b.ImageModel {
			return target, configured, nil
		}
		return ProviderTarget{Provider: b.ImageProvider, Model: b.ImageModel}, configured, nil
	}
	if rawEngine != nil && engine == "" {
		return ProviderTarget{}, "", invalidPreparation("unsupported video engine")
	}
	configured := firstConfiguredEngine(b.VideoEngine, b.VideoProvider, "video")
	if engine == "" {
		engine = configured
	}
	if rawModel != nil {
		model := stringValue(rawModel)
		if model == "" || (engine != "seedance" && engine != "bailian" && engine != "minimax") {
			return ProviderTarget{}, "", invalidPreparation("unsupported video model")
		}
		target, ok := b.VideoModels[model]
		if !ok || target.Provider != engine || target.Model == "" {
			return ProviderTarget{}, "", invalidPreparation("unsupported video model")
		}
		return target, engine, nil
	}
	if engine != "" {
		if engine != "seedance" && engine != "bailian" && engine != "minimax" {
			return ProviderTarget{}, "", invalidPreparation("unsupported video engine")
		}
		target, ok := b.VideoEngines[engine]
		if !ok || target.Provider == "" || target.Model == "" {
			return ProviderTarget{}, "", errors.New("provider job builder is not configured")
		}
		return target, engine, nil
	}
	if target, ok := b.VideoEngines[configured]; ok && target.Provider == b.VideoProvider && target.Model == b.VideoModel {
		return target, configured, nil
	}
	return ProviderTarget{Provider: b.VideoProvider, Model: b.VideoModel}, configured, nil
}

func firstConfiguredEngine(configured, provider, capabilityKind string) string {
	if engine := engineName(configured); engine != "" {
		return engine
	}
	if capabilityKind == "image" {
		switch provider {
		case "volcengine-visual":
			return "jimeng"
		case "evolink", "bailian", "seedream":
			return provider
		}
	} else if provider == "seedance" || provider == "bailian" || provider == "minimax" {
		return provider
	}
	return ""
}

type preparedProviderRequest struct {
	request  providers.Request
	assetIDs []string
}

func prepareProviderRequest(capability, engine, model string, defaults map[string]any, body map[string]any) (preparedProviderRequest, error) {
	materials, assembly, err := preparationMaterials(body, capability)
	if err != nil {
		return preparedProviderRequest{}, err
	}
	text := stringValue(body["prompt"])
	if text == "" && assembly != nil {
		text = prompt.Assemble(*assembly).Prompt
	}
	text = strings.TrimSpace(text)
	if text == "" && !seedreamLayerDecompositionRequested(capability, engine, body) {
		return preparedProviderRequest{}, invalidPreparation("prompt is required")
	}
	assetIDs := stringsFromAny(body["inputAssetIds"])
	if len(assetIDs) == 0 {
		for _, material := range materials {
			if material.ID != "" {
				assetIDs = append(assetIDs, material.ID)
			}
		}
	}
	var urls []string
	var settings map[string]any
	if capability == "image.generate" {
		urls = stringsFromAny(firstNonNil(body["imageUrls"], body["inputUrls"]))
		if len(urls) == 0 {
			for _, material := range materials {
				if material.Type == "image" {
					urls = append(urls, material.URL)
				}
			}
		}
		if err := validateImageCoverage(text, materials, len(urls)); err != nil {
			return preparedProviderRequest{}, err
		}
		settings, err = imageSettings(body)
		if err == nil {
			applyImageSettingDefaults(settings, defaults)
		}
		if err == nil && engine == "evolink" && isEvoLinkImage25(model) {
			err = validateEvoLinkImageQuality(body, settings)
		}
		if err == nil && engine == "evolink" && isEvoLinkImage25(model) {
			err = validateEvoLinkImage25(body, urls, settings)
		}
		if err == nil && engine == "bailian" {
			err = validateBailianImage(urls, settings)
		}
		if err == nil && engine == "seedream" {
			err = validateSeedreamImage(urls, materials, settings)
		}
	} else {
		if err := validateMaterialCoverage(text, materials); err != nil {
			return preparedProviderRequest{}, err
		}
		for _, material := range materials {
			urls = append(urls, material.URL)
		}
		settings, err = videoSettings(engine, model, defaults, body["settings"], materials)
	}
	if err != nil {
		return preparedProviderRequest{}, err
	}
	providerMaterials := make([]providers.Material, 0, len(materials))
	for _, material := range materials {
		materialType := providers.MaterialImage
		switch material.Type {
		case "video":
			materialType = providers.MaterialVideo
		case "audio":
			materialType = providers.MaterialAudio
		}
		providerMaterials = append(providerMaterials, providers.Material{
			URL: material.URL, Type: materialType, Role: material.Role, Label: material.Label,
		})
	}
	return preparedProviderRequest{request: providers.Request{Capability: capability, Prompt: text, InputURLs: urls, Materials: providerMaterials, Settings: settings}, assetIDs: assetIDs}, nil
}

func validateEvoLinkImageQuality(body, settings map[string]any) error {
	quality := body["quality"]
	if quality == nil {
		if nested, ok := body["settings"].(map[string]any); ok {
			quality = nested["quality"]
		}
	}
	if quality != nil {
		value, ok := quality.(string)
		if !ok || !validImageQuality(strings.ToLower(strings.TrimSpace(value))) {
			return invalidPreparation("invalid image parameter: quality")
		}
	}
	if settings["quality"] == nil {
		settings["quality"] = "medium"
	}
	value, ok := settings["quality"].(string)
	if !ok || !validImageQuality(value) {
		return invalidPreparation("invalid image parameter: quality")
	}
	return nil
}

func validImageQuality(value string) bool {
	return value == "low" || value == "medium" || value == "high"
}

func isEvoLinkImage25(model string) bool {
	return model == "gpt-image-2.5-flare" || model == "gpt-image-2.5-sunburst"
}

func validateEvoLinkImage25(body map[string]any, urls []string, settings map[string]any) error {
	if len(urls) > 16 {
		return invalidPreparation("EvoLink Image 2.5 supports at most 16 reference images")
	}
	resolutions := []any{body["resolution"]}
	counts := []any{body["n"]}
	if nested, ok := body["settings"].(map[string]any); ok {
		resolutions = append(resolutions, nested["resolution"])
		counts = append(counts, nested["n"])
	}
	for _, resolution := range resolutions {
		if resolution != nil && !strings.EqualFold(strings.TrimSpace(stringValue(resolution)), "1K") {
			return invalidPreparation("EvoLink Image 2.5 resolution must be 1K")
		}
	}
	for _, count := range counts {
		if count != nil {
			value, ok := finiteNumber(count)
			if !ok || value != 1 {
				return invalidPreparation("EvoLink Image 2.5 n must be 1")
			}
		}
	}
	if raw := settings["imageCount"]; raw != nil {
		count, ok := finiteNumber(raw)
		if !ok || count != 1 {
			return invalidPreparation("EvoLink Image 2.5 imageCount must be 1")
		}
	}
	if settings["force_single"] == false {
		return invalidPreparation("EvoLink Image 2.5 requires force_single")
	}
	if raw := settings["size"]; raw != nil {
		size, _ := raw.(string)
		if !evoLink1KSize(size) {
			return invalidPreparation("EvoLink Image 2.5 size must be a supported 1K aspect ratio or A4 size")
		}
	}
	widthRaw, heightRaw := settings["width"], settings["height"]
	if (widthRaw == nil) != (heightRaw == nil) {
		return invalidPreparation("EvoLink Image 2.5 requires both width and height")
	}
	if widthRaw != nil {
		width, widthOK := finiteNumber(widthRaw)
		height, heightOK := finiteNumber(heightRaw)
		if !widthOK || !heightOK || width < 1 || height < 1 || width > 8192 || height > 8192 || width != math.Trunc(width) || height != math.Trunc(height) {
			return invalidPreparation("invalid EvoLink Image 2.5 dimensions")
		}
		if !evoLink1KDimensions(int(width), int(height)) {
			return invalidPreparation("EvoLink Image 2.5 custom dimensions exceed the supported 1K size")
		}
	} else if settings["size"] == nil {
		// EvoLink's auto size may choose a larger output even with resolution=1K.
		settings["size"] = "1:1"
	}
	settings["imageCount"] = float64(1)
	return nil
}

func evoLink1KSize(size string) bool {
	switch strings.TrimSpace(size) {
	case "1:1", "1:2", "2:1", "1:3", "3:1", "2:3", "3:2", "3:4", "4:3", "4:5", "5:4", "9:16", "16:9", "9:21", "21:9", "848x1200", "1200x848":
		return true
	default:
		return false
	}
}

func evoLink1KDimensions(width, height int) bool {
	if (width == 848 && height == 1200) || (width == 1200 && height == 848) ||
		(width == 1680 && height == 2376) || (width == 2376 && height == 1680) {
		return true
	}
	divisor := gcdImageDimensions(width, height)
	if evoLink1KSize(fmt.Sprintf("%d:%d", width/divisor, height/divisor)) {
		return true
	}
	shorter, longer := min(width, height), max(width, height)
	pixels := width * height
	return width%16 == 0 && height%16 == 0 &&
		pixels >= 655360 && pixels <= 1024*1024 && longer <= 3*shorter
}

func gcdImageDimensions(left, right int) int {
	for right != 0 {
		left, right = right, left%right
	}
	return left
}

func applyImageSettingDefaults(settings, defaults map[string]any) {
	for key, value := range defaults {
		if _, configured := settings[key]; !configured {
			settings[key] = value
		}
	}
}

func validateImageCoverage(text string, materials []prompt.Material, imageURLCount int) error {
	required := prompt.ExtractRequirements(text)
	if required.Video > 0 || required.Audio > 0 {
		return validateMaterialCoverage(text, materials)
	}
	if required.Image > imageURLCount {
		return invalidPreparation(fmt.Sprintf("prompt requires @图片%d but only %d image materials were supplied", required.Image, imageURLCount))
	}
	return nil
}

func preparationMaterials(body map[string]any, capability string) ([]prompt.Material, *prompt.Input, error) {
	assemblyRecord, hasAssembly := body["promptAssembly"].(map[string]any)
	var assembly *prompt.Input
	if hasAssembly {
		var decoded prompt.Input
		if err := decodeViaJSON(assemblyRecord, &decoded); err != nil {
			return nil, nil, invalidPreparation("invalid promptAssembly")
		}
		if capability == "image.generate" {
			decoded.Mode = "image"
		} else {
			decoded.Mode = "video"
		}
		assembly = &decoded
	}
	var materials []prompt.Material
	if raw, ok := body["materials"]; ok {
		if err := decodeViaJSON(raw, &materials); err != nil {
			return nil, nil, invalidPreparation("invalid materials")
		}
	} else if assembly != nil {
		materials = assembly.Materials
	}
	materials = prompt.NormalizeMaterials(materials)
	if assembly != nil {
		assembly.Materials = materials
	}
	return materials, assembly, nil
}

func validateMaterialCoverage(text string, materials []prompt.Material) error {
	required := prompt.ExtractRequirements(text)
	available := prompt.Requirements{}
	for _, material := range materials {
		switch material.Type {
		case "video":
			available.Video++
		case "audio":
			available.Audio++
		default:
			available.Image++
		}
	}
	if required.Image > available.Image {
		return invalidPreparation(fmt.Sprintf("prompt requires @图片%d but only %d image materials were supplied", required.Image, available.Image))
	}
	if required.Video > available.Video {
		return invalidPreparation(fmt.Sprintf("prompt requires @视频%d but only %d video materials were supplied", required.Video, available.Video))
	}
	if required.Audio > available.Audio {
		return invalidPreparation(fmt.Sprintf("prompt requires @音频%d but only %d audio materials were supplied", required.Audio, available.Audio))
	}
	return nil
}

func imageSettings(body map[string]any) (map[string]any, error) {
	out := map[string]any{}
	if nested, ok := body["settings"].(map[string]any); ok {
		for _, key := range []string{"scale", "width", "height", "min_ratio", "max_ratio", "imageCount", "force_single", "quality", "size", "outputFormat", "optimizeMode", "creationMode", "layerDecomposition"} {
			if nested[key] != nil {
				out[key] = nested[key]
			}
		}
	}
	for _, key := range []string{"scale", "width", "height", "min_ratio", "max_ratio", "imageCount"} {
		raw := body[key]
		if raw == nil {
			raw = out[key]
		}
		if value, ok := finiteNumber(raw); ok {
			out[key] = value
		} else if raw != nil && raw != "" {
			return nil, invalidPreparation("invalid image parameter: " + key)
		} else {
			delete(out, key)
		}
	}
	forceSingle := body["force_single"]
	if forceSingle == nil {
		forceSingle = out["force_single"]
	}
	if value, ok := forceSingle.(bool); ok {
		out["force_single"] = value
	} else if forceSingle != nil {
		return nil, invalidPreparation("invalid image parameter: force_single")
	} else {
		delete(out, "force_single")
	}
	qualityRaw := body["quality"]
	if qualityRaw == nil {
		qualityRaw = out["quality"]
	}
	delete(out, "quality")
	if raw, ok := qualityRaw.(string); ok {
		quality := strings.ToLower(strings.TrimSpace(raw))
		if quality == "low" || quality == "medium" || quality == "high" {
			out["quality"] = quality
		}
	}
	for _, key := range []string{"size", "outputFormat", "optimizeMode"} {
		raw := body[key]
		if raw == nil {
			raw = out[key]
		}
		delete(out, key)
		if raw == nil || raw == "" {
			continue
		}
		value, ok := raw.(string)
		if !ok || strings.TrimSpace(value) == "" {
			return nil, invalidPreparation("invalid image parameter: " + key)
		}
		out[key] = strings.TrimSpace(value)
	}
	creationModeRaw := firstNonNil(body["creationMode"], out["creationMode"])
	delete(out, "creationMode")
	if creationModeRaw != nil && creationModeRaw != "" {
		value, ok := creationModeRaw.(string)
		if !ok || strings.TrimSpace(value) == "" {
			return nil, invalidPreparation("invalid image parameter: creationMode")
		}
		out["creationMode"] = strings.ToLower(strings.TrimSpace(value))
	}
	layerRaw := firstNonNil(body["layerDecomposition"], out["layerDecomposition"])
	delete(out, "layerDecomposition")
	if layerRaw != nil {
		value, ok := layerRaw.(bool)
		if !ok {
			return nil, invalidPreparation("invalid image parameter: layerDecomposition")
		}
		out["layerDecomposition"] = value
	}
	if count, ok := out["imageCount"].(float64); ok && (count <= 0 || count > 9 || math.Trunc(count) != count) {
		return nil, invalidPreparation("imageCount must be an integer between 1 and 9")
	}
	return out, nil
}

func validateSeedreamImage(urls []string, materials []prompt.Material, settings map[string]any) error {
	creationMode := strings.ToLower(strings.TrimSpace(stringValue(settings["creationMode"])))
	layerDecomposition, _ := settings["layerDecomposition"].(bool)
	if layerDecomposition {
		creationMode = "layers"
	}
	if creationMode == "" {
		creationMode = "basic"
	}
	if creationMode != "basic" && creationMode != "interactive" && creationMode != "layers" {
		return invalidPreparation("unsupported seedream creation mode")
	}
	if creationMode == "basic" && len(urls) > 10 {
		return invalidPreparation("seedream supports at most 10 reference images")
	}
	if creationMode == "interactive" && (len(urls) < 1 || len(urls) > 10) {
		return invalidPreparation("seedream interactive editing requires between 1 and 10 input images")
	}
	if creationMode == "layers" && len(urls) != 1 {
		return invalidPreparation("seedream layer decomposition requires exactly one input image")
	}
	for _, material := range materials {
		if material.Type != "image" {
			return invalidPreparation("seedream supports image materials only")
		}
	}
	if settings["width"] != nil || settings["height"] != nil {
		return invalidPreparation("seedream requires a size preset instead of width and height")
	}
	size := strings.ToUpper(strings.TrimSpace(stringValue(settings["size"])))
	if creationMode == "layers" && size == "AUTO" {
		size = "auto"
	} else if size != "1K" && size != "1.5K" && size != "2K" {
		if creationMode == "layers" {
			return invalidPreparation("seedream layer size must be auto, 1K, 1.5K, or 2K")
		}
		return invalidPreparation("seedream size must be 1K, 1.5K, or 2K")
	}
	format := strings.ToLower(strings.TrimSpace(stringValue(settings["outputFormat"])))
	if format != "png" && format != "jpeg" {
		return invalidPreparation("seedream output format must be png or jpeg")
	}
	mode := strings.ToLower(strings.TrimSpace(stringValue(settings["optimizeMode"])))
	if mode != "standard" && mode != "fast" {
		return invalidPreparation("seedream prompt optimization mode must be standard or fast")
	}
	if count, ok := finiteNumber(settings["imageCount"]); ok && count != 1 {
		return invalidPreparation("seedream basic generation supports one output image")
	}
	settings["size"] = size
	settings["outputFormat"] = format
	settings["optimizeMode"] = mode
	settings["imageCount"] = float64(1)
	settings["creationMode"] = creationMode
	if creationMode == "layers" {
		settings["layerDecomposition"] = true
	} else {
		delete(settings, "layerDecomposition")
	}
	return nil
}

func seedreamLayerDecompositionRequested(capability, engine string, body map[string]any) bool {
	if capability != "image.generate" || engine != "seedream" {
		return false
	}
	settings, _ := body["settings"].(map[string]any)
	if value, ok := firstNonNil(body["layerDecomposition"], settings["layerDecomposition"]).(bool); ok && value {
		return true
	}
	return strings.EqualFold(strings.TrimSpace(stringValue(firstNonNil(body["creationMode"], settings["creationMode"]))), "layers")
}

func validateBailianImage(urls []string, settings map[string]any) error {
	if len(urls) > 9 {
		return invalidPreparation("bailian supports at most 9 reference images")
	}
	width, hasWidth := settings["width"].(float64)
	height, hasHeight := settings["height"].(float64)
	if !hasWidth && !hasHeight {
		return nil
	}
	if !hasWidth || !hasHeight || math.Trunc(width) != width || math.Trunc(height) != height || width <= 0 || height <= 0 {
		return invalidPreparation("bailian image dimensions must be positive integers")
	}
	pixels := width * height
	maximum := float64(4096 * 4096)
	if len(urls) > 0 {
		maximum = float64(2048 * 2048)
	}
	if pixels < float64(768*768) || pixels > maximum || width/height < 1.0/8.0 || width/height > 8 {
		return invalidPreparation("bailian image dimensions are outside supported size constraints")
	}
	return nil
}

const (
	seedance20Model = "doubao-seedance-2-0-260128"
	seedance25Model = "doubao-seedance-2-5-260628"
	wan30VideoModel = "wan3.0-video"
)

func videoSettings(engine, model string, defaults map[string]any, raw any, materials []prompt.Material) (map[string]any, error) {
	input, _ := raw.(map[string]any)
	merged := make(map[string]any, len(defaults)+len(input))
	for key, value := range defaults {
		merged[key] = value
	}
	for key, value := range input {
		merged[key] = value
	}
	input = merged
	settings := map[string]any{}
	if engine == "minimax" {
		if model != providers.MinimaxH3Model {
			return nil, invalidPreparation("unsupported MiniMax video model")
		}
		mode := stringValue(input["inputMode"])
		if mode != "" && mode != "frames" && mode != "reference" {
			return nil, invalidPreparation("MiniMax 请选择首帧或多图参考模式")
		}
		if mode == "reference" {
			if len(materials) > 9 {
				return nil, invalidPreparation("MiniMax 多图参考模式最多支持 9 张图片")
			}
		} else if len(materials) > 1 {
			return nil, invalidPreparation("MiniMax 首帧模式最多只能上传 1 张图片；多张图片请切换到多图参考模式")
		}
		for _, material := range materials {
			if material.Type != "image" {
				return nil, invalidPreparation("MiniMax 当前仅支持图片素材，请移除视频或音频")
			}
		}
		duration := float64(5)
		if input["duration"] != nil {
			var ok bool
			duration, ok = finiteNumber(input["duration"])
			if !ok || math.Trunc(duration) != duration || duration < 4 || duration > 15 {
				return nil, invalidPreparation("MiniMax H3 video duration must be an integer between 4 and 15 seconds")
			}
		}
		resolution := strings.ToUpper(stringValue(input["resolution"]))
		if resolution == "" {
			resolution = "768P"
		}
		if resolution != "768P" && resolution != "2K" {
			return nil, invalidPreparation("MiniMax H3 video resolution must be 768P or 2K")
		}
		ratio := stringValue(input["ratio"])
		if mode != "reference" && len(materials) == 1 {
			ratio = "adaptive"
		} else {
			if ratio == "" {
				ratio = "16:9"
			}
			if (len(materials) == 0 && ratio == "adaptive") || !oneOf(ratio, "21:9", "16:9", "4:3", "1:1", "3:4", "9:16", "adaptive") {
				return nil, invalidPreparation("MiniMax H3 text-to-video requires a fixed supported ratio")
			}
		}
		settings := map[string]any{"duration": duration, "resolution": resolution, "ratio": ratio}
		if mode != "" {
			settings["inputMode"] = mode
		}
		return settings, nil
	}
	if engine == "bailian" {
		wan30 := model == wan30VideoModel
		mode := stringValue(input["inputMode"])
		if mode == "" && wan30 {
			mode = "reference"
		}
		if mode != "" && mode != "frames" && mode != "reference" {
			return nil, invalidPreparation("百炼请选择首尾帧或多图参考模式")
		}
		if !wan30 && mode == "reference" {
			return nil, invalidPreparation("Wan 2.7 仅支持首尾帧；多图参考请选择 Wan 3.0")
		}
		if mode == "reference" && len(materials) > 10 {
			return nil, invalidPreparation("Wan 3.0 多图参考模式最多支持 10 张图片")
		}
		if mode != "reference" && (len(materials) < 1 || len(materials) > 2) {
			return nil, invalidPreparation("bailian video requires 1 or 2 image materials")
		}
		for _, material := range materials {
			if material.Type != "image" {
				return nil, invalidPreparation("百炼当前视频模式仅支持图片素材，请移除视频或音频")
			}
		}
		duration := float64(10)
		if input["duration"] != nil {
			var ok bool
			duration, ok = finiteNumber(input["duration"])
			maximum := float64(15)
			if wan30 {
				maximum = 30
			}
			if !ok || math.Trunc(duration) != duration || duration < 2 || duration > maximum {
				return nil, invalidPreparation(fmt.Sprintf("百炼视频时长需为 2–%.0f 秒整数", maximum))
			}
		}
		resolution := strings.ToUpper(stringValue(input["resolution"]))
		if resolution == "" {
			resolution = "720P"
		}
		if resolution != "720P" && resolution != "1080P" && !(wan30 && resolution == "480P") {
			return nil, invalidPreparation("百炼视频分辨率不支持当前设置")
		}
		settings := map[string]any{"duration": duration, "resolution": resolution}
		if wan30 {
			ratio := stringValue(input["ratio"])
			if ratio != "" {
				if !oneOf(ratio, "adaptive", "21:9", "16:9", "4:3", "1:1", "3:4", "9:16") {
					return nil, invalidPreparation("Wan 3.0 画面比例支持自适应、21:9、16:9、4:3、1:1、3:4 或 9:16")
				}
				settings["ratio"] = ratio
			}
		}
		if mode != "" {
			settings["inputMode"] = mode
		}
		return settings, nil
	}
	if engine != "" && engine != "seedance" {
		return nil, invalidPreparation("unsupported video engine")
	}
	if model == seedance25Model {
		counts := map[string]int{"image": 0, "video": 0, "audio": 0}
		for _, material := range materials {
			counts[material.Type]++
		}
		if len(materials) > 50 || counts["image"] > 30 || counts["video"] > 10 || counts["audio"] > 10 {
			return nil, invalidPreparation("seedance 2.5 supports at most 30 image, 10 video, and 10 audio materials")
		}
	} else {
		counts := map[string]int{"image": 0, "video": 0, "audio": 0}
		for _, material := range materials {
			counts[material.Type]++
		}
		if counts["image"] > 9 || counts["video"] > 3 || counts["audio"] > 3 {
			return nil, invalidPreparation("Seedance 2.0 最多支持 9 张图片、3 个视频、3 个音频")
		}
		if counts["audio"] > 0 && counts["image"]+counts["video"] == 0 {
			return nil, invalidPreparation("Seedance 2.0 的音频不能单独使用，请添加图片或视频素材")
		}
	}
	ratio := stringValue(input["ratio"])
	if ratio != "" && !oneOf(ratio, "9:16", "16:9", "1:1", "4:3", "3:4", "21:9", "adaptive") {
		return nil, invalidPreparation("unsupported video ratio")
	}
	if ratio != "" {
		settings["ratio"] = ratio
	}
	if input["duration"] != nil {
		duration, ok := finiteNumber(input["duration"])
		maximum := float64(15)
		if model == seedance25Model {
			maximum = 30
		}
		if !ok || math.Trunc(duration) != duration || duration < 4 || duration > maximum {
			return nil, invalidPreparation(fmt.Sprintf("video duration must be an integer between 4 and %.0f seconds", maximum))
		}
		settings["duration"] = duration
	}
	resolution := stringValue(input["resolution"])
	if resolution != "" && !oneOf(resolution, "480p", "720p", "1080p") {
		return nil, invalidPreparation("unsupported video resolution")
	}
	if resolution != "" {
		settings["resolution"] = resolution
	}
	return settings, nil
}

func invalidPreparation(message string) error {
	return &Error{Kind: ErrorInvalid, Status: 400, Message: message}
}

func decodeViaJSON(input, output any) error {
	raw, err := json.Marshal(input)
	if err != nil {
		return err
	}
	return json.Unmarshal(raw, output)
}

func finiteNumber(value any) (float64, bool) {
	var number float64
	switch typed := value.(type) {
	case float64:
		number = typed
	case float32:
		number = float64(typed)
	case int:
		number = float64(typed)
	case int64:
		number = float64(typed)
	default:
		return 0, false
	}
	return number, !math.IsNaN(number) && !math.IsInf(number, 0)
}

func stringValue(value any) string {
	text, _ := value.(string)
	return strings.TrimSpace(text)
}

func engineName(value any) string { return strings.ToLower(stringValue(value)) }

func oneOf(value string, options ...string) bool {
	for _, option := range options {
		if value == option {
			return true
		}
	}
	return false
}

func stringsFromAny(v any) []string {
	if values, ok := v.([]string); ok {
		out := make([]string, 0, len(values))
		for _, value := range values {
			if value = strings.TrimSpace(value); value != "" {
				out = append(out, value)
			}
		}
		return out
	}
	values, _ := v.([]any)
	out := []string{}
	for _, x := range values {
		if s, ok := x.(string); ok && strings.TrimSpace(s) != "" {
			out = append(out, strings.TrimSpace(s))
		}
	}
	return out
}
func intFromAny(v any) int {
	switch x := v.(type) {
	case float64:
		return int(x)
	case int:
		return x
	}
	return 0
}
func firstNonNil(v ...any) any {
	for _, x := range v {
		if x != nil {
			return x
		}
	}
	return nil
}