package clients

import (
	"bytes"
	"context"
	"encoding/json"
	"errors"
	"fmt"
	"net/http"
	"strings"
	"time"

	scriptengine "github.com/easyai/easyai-ai-gateway/apps/api/internal/script"
)

type UniversalClient struct {
	HTTPClient     *http.Client
	ScriptExecutor *scriptengine.Executor
}

func (c UniversalClient) Run(ctx context.Context, request Request) (Response, error) {
	executor := c.ScriptExecutor
	if executor == nil {
		executor = &scriptengine.Executor{}
	}
	startedAt := time.Now()
	modelType := strings.TrimSpace(request.ModelType)
	if modelType == "" {
		modelType = strings.TrimSpace(request.Candidate.ModelType)
	}

	payload := cloneBody(request.Body)
	upstreamTaskID := strings.TrimSpace(request.RemoteTaskID)
	submitRequestID := upstreamTaskID
	var submitResult map[string]any

	if upstreamTaskID == "" {
		var err error
		payload, err = c.universalGetParams(ctx, executor, request, modelType)
		if err != nil {
			return Response{}, err
		}
		submitResult, submitRequestID, err = c.universalSubmit(ctx, executor, request, modelType, payload)
		if err != nil {
			return Response{}, annotateResponseError(err, submitRequestID, startedAt, time.Now())
		}
		if isUniversalSuccess(submitResult) && submitResult["data"] != nil {
			return Response{
				Result:             normalizeUniversalResult(request, submitResult, ""),
				RequestID:          firstNonEmptyString(submitRequestID, requestIDFromResult(submitResult)),
				Progress:           providerProgress(request),
				ResponseStartedAt:  startedAt,
				ResponseFinishedAt: time.Now(),
				ResponseDurationMS: responseDurationMS(startedAt, time.Now()),
			}, nil
		}
		if isUniversalFailure(submitResult) {
			return Response{}, universalFailureError(submitResult, firstNonEmptyString(submitRequestID, requestIDFromResult(submitResult)), startedAt)
		}
		upstreamTaskID = universalTaskID(submitResult)
		if upstreamTaskID == "" {
			return Response{}, &ClientError{Code: "invalid_response", Message: "universal task id is missing", RequestID: submitRequestID, Retryable: false}
		}
		if request.OnRemoteTaskSubmitted != nil {
			if err := request.OnRemoteTaskSubmitted(upstreamTaskID, map[string]any{"payload": payload, "submit": submitResult}); err != nil {
				return Response{}, err
			}
		}
	} else if request.RemoteTaskPayload != nil {
		if existingPayload, ok := request.RemoteTaskPayload["payload"].(map[string]any); ok {
			payload = existingPayload
		}
	}

	result, requestID, err := c.universalPollUntilDone(ctx, executor, request, modelType, upstreamTaskID, payload, firstNonEmptyString(submitRequestID, upstreamTaskID), startedAt)
	if err != nil {
		return Response{}, err
	}
	finishedAt := time.Now()
	return Response{
		Result:             normalizeUniversalResult(request, result, upstreamTaskID),
		RequestID:          firstNonEmptyString(requestID, submitRequestID, requestIDFromResult(result), upstreamTaskID),
		Progress:           universalProgress(request, upstreamTaskID),
		ResponseStartedAt:  startedAt,
		ResponseFinishedAt: finishedAt,
		ResponseDurationMS: responseDurationMS(startedAt, finishedAt),
	}, nil
}

func (c UniversalClient) universalGetParams(ctx context.Context, executor *scriptengine.Executor, request Request, modelType string) (map[string]any, error) {
	if scriptText := universalSceneScript(request.Candidate.PlatformConfig, modelType, "customGetParamsScript", "custom_get_params_script"); scriptText != "" {
		scriptContext := universalScriptContext(request, modelType, nil)
		out, err := executor.Execute(ctx, scriptengine.Options{
			Script:              scriptText,
			Args:                []any{cloneBody(request.Body), scriptContext},
			ContextData:         scriptContext,
			ScriptName:          "custom_get_params_script:" + modelType,
			PreferredEntryNames: []string{"getGenerateParams", "getParams", "main", "handler"},
			Timeout:             30 * time.Second,
			HTTPClient:          httpClient(request.HTTPClient, c.HTTPClient),
		})
		if err != nil {
			return nil, universalScriptError(err)
		}
		if params, ok := out.(map[string]any); ok && params != nil {
			if params["_originalParams"] == nil {
				params["_originalParams"] = cloneBody(request.Body)
			}
			return params, nil
		}
		return nil, &ClientError{Code: "invalid_response", Message: "custom get params script must return an object", Retryable: false}
	}
	body := universalDefaultPayload(request)
	body["_originalParams"] = cloneBody(request.Body)
	return body, nil
}

func (c UniversalClient) universalSubmit(ctx context.Context, executor *scriptengine.Executor, request Request, modelType string, payload map[string]any) (map[string]any, string, error) {
	if scriptText := universalSceneScript(request.Candidate.PlatformConfig, modelType, "customSubmitScript", "custom_submit_script"); scriptText != "" {
		scriptContext := universalScriptContext(request, modelType, payload)
		out, err := executor.Execute(ctx, scriptengine.Options{
			Script:              scriptText,
			Args:                []any{cloneBody(payload), scriptContext},
			ContextData:         scriptContext,
			ScriptName:          "custom_submit_script:" + modelType,
			PreferredEntryNames: []string{"submitTask", "submitParams", "submit", "main", "handler"},
			Timeout:             30 * time.Second,
			HTTPClient:          httpClient(request.HTTPClient, c.HTTPClient),
		})
		if err != nil {
			return nil, "", universalScriptError(err)
		}
		result, ok := out.(map[string]any)
		if !ok || result == nil {
			return nil, "", &ClientError{Code: "invalid_response", Message: "custom submit script must return an object", Retryable: false}
		}
		return result, requestIDFromResult(result), nil
	}
	endpoint := universalSubmitEndpoint(request)
	result, requestID, err := universalPostJSON(ctx, httpClient(request.HTTPClient, c.HTTPClient), request.Candidate.BaseURL, endpoint, universalStripPrivatePayload(payload), request.Candidate.Credentials)
	return result, requestID, err
}

func (c UniversalClient) universalPollUntilDone(ctx context.Context, executor *scriptengine.Executor, request Request, modelType string, upstreamTaskID string, payload map[string]any, requestID string, startedAt time.Time) (map[string]any, string, error) {
	interval := universalDurationConfig(request.Candidate.PlatformConfig, 2*time.Second, "pollIntervalMs", "poll_interval_ms")
	timeout := universalDurationConfig(request.Candidate.PlatformConfig, 10*time.Minute, "pollTimeoutMs", "poll_timeout_ms", "timeoutMs")
	deadline := time.NewTimer(timeout)
	defer deadline.Stop()
	ticker := time.NewTicker(interval)
	defer ticker.Stop()

	var lastResult map[string]any
	for {
		pollStarted := time.Now()
		result, pollRequestID, err := c.universalPoll(ctx, executor, request, modelType, upstreamTaskID, payload)
		pollFinished := time.Now()
		if err != nil {
			return nil, "", annotateResponseError(err, firstNonEmptyString(pollRequestID, requestID, upstreamTaskID), pollStarted, pollFinished)
		}
		lastResult = result
		requestID = firstNonEmptyString(pollRequestID, requestID, requestIDFromResult(result), upstreamTaskID)
		if isUniversalSuccess(result) {
			return result, requestID, nil
		}
		if isUniversalFailure(result) {
			return nil, "", universalFailureError(result, requestID, startedAt)
		}
		select {
		case <-ctx.Done():
			return nil, "", &ClientError{Code: "cancelled", Message: ctx.Err().Error(), RequestID: requestID, Retryable: true}
		case <-deadline.C:
			return nil, "", &ClientError{Code: "timeout", Message: fmt.Sprintf("universal task %s did not finish before timeout; last status: %s", upstreamTaskID, universalStatus(lastResult)), RequestID: requestID, Retryable: true}
		case <-ticker.C:
		}
	}
}

func (c UniversalClient) universalPoll(ctx context.Context, executor *scriptengine.Executor, request Request, modelType string, upstreamTaskID string, payload map[string]any) (map[string]any, string, error) {
	if scriptText := universalSceneScript(request.Candidate.PlatformConfig, modelType, "customPollScript", "custom_poll_script"); scriptText != "" {
		scriptContext := universalScriptContext(request, modelType, payload)
		out, err := executor.Execute(ctx, scriptengine.Options{
			Script:              scriptText,
			Args:                []any{upstreamTaskID, scriptContext},
			ContextData:         scriptContext,
			ScriptName:          "custom_poll_script:" + modelType,
			PreferredEntryNames: []string{"pollTask", "poll", "main", "handler"},
			Timeout:             30 * time.Second,
			HTTPClient:          httpClient(request.HTTPClient, c.HTTPClient),
		})
		if err != nil {
			return nil, "", universalScriptError(err)
		}
		result, ok := out.(map[string]any)
		if !ok || result == nil {
			return nil, "", &ClientError{Code: "invalid_response", Message: "custom poll script must return an object", Retryable: false}
		}
		return result, requestIDFromResult(result), nil
	}
	pollURL := resolveUniversalTaskURL(request.Candidate.PlatformConfig, upstreamTaskID)
	if pollURL == "" {
		return nil, "", &ClientError{Code: "missing_configuration", Message: "universal getTaskURL is required", Retryable: false}
	}
	return universalGetJSON(ctx, httpClient(request.HTTPClient, c.HTTPClient), pollURL, request.Candidate.Credentials)
}

func universalScriptContext(request Request, modelType string, payload map[string]any) map[string]any {
	baseURL := strings.TrimRight(strings.TrimSpace(request.Candidate.BaseURL), "/")
	getTaskURL := universalConfigString(request.Candidate.PlatformConfig, "getTaskURL", "get_task_url")
	context := map[string]any{
		"__easyaiScriptContext": true,
		"baseURL":               baseURL,
		"getTaskURL":            getTaskURL,
		"authValues":            cloneMapAny(request.Candidate.Credentials),
		"headers":               map[string]any{},
		"payload":               cloneMapAny(payload),
		"type":                  modelType,
		"options": map[string]any{
			"task_id":           request.RemoteTaskID,
			"upstream_task_id":  request.RemoteTaskID,
			"model":             request.Model,
			"providerModelName": request.Candidate.ProviderModelName,
			"platformId":        request.Candidate.PlatformID,
			"platformModelId":   request.Candidate.PlatformModelID,
			"canonicalModelKey": request.Candidate.CanonicalModelKey,
			"modelType":         modelType,
			"timeout":           universalDurationConfig(request.Candidate.PlatformConfig, 10*time.Minute, "pollTimeoutMs", "poll_timeout_ms").Milliseconds(),
		},
		"env":       cloneMapAny(request.Candidate.PlatformConfig),
		"candidate": universalCandidateSnapshot(request),
	}
	context["createRequestURL"] = func(path string, base ...string) string {
		selectedBase := baseURL
		if len(base) > 0 && strings.TrimSpace(base[0]) != "" {
			selectedBase = strings.TrimRight(strings.TrimSpace(base[0]), "/")
		}
		if strings.HasPrefix(path, "http://") || strings.HasPrefix(path, "https://") {
			return path
		}
		return selectedBase + "/" + strings.TrimLeft(path, "/")
	}
	context["creatRequestURL"] = context["createRequestURL"]
	context["resolveGetTaskURL"] = func(taskID string) string {
		return resolveUniversalTaskURL(request.Candidate.PlatformConfig, taskID)
	}
	return context
}

func universalCandidateSnapshot(request Request) map[string]any {
	return map[string]any{
		"modelName":         request.Candidate.ModelName,
		"modelAlias":        request.Candidate.ModelAlias,
		"providerModelName": request.Candidate.ProviderModelName,
		"provider":          request.Candidate.Provider,
		"platformId":        request.Candidate.PlatformID,
		"platformModelId":   request.Candidate.PlatformModelID,
		"capabilities":      cloneMapAny(request.Candidate.Capabilities),
	}
}

func universalDefaultPayload(request Request) map[string]any {
	body := cloneBody(request.Body)
	body["model"] = upstreamModelName(request.Candidate)
	if request.Kind == "images.generations" {
		if n := firstPresent(body["n"], body["numImages"]); n != nil {
			body["numImages"] = n
		}
		if aspectRatio := strings.TrimSpace(stringFromAny(body["aspect_ratio"])); aspectRatio != "" {
			body["aspectRatio"] = aspectRatio
		}
	}
	return body
}

func universalSubmitEndpoint(request Request) string {
	if endpoint := universalConfigString(request.Candidate.PlatformConfig, "submitPath", "submit_path"); endpoint != "" {
		return endpoint
	}
	switch request.Kind {
	case "images.generations":
		return "/images/generations"
	case "images.edits":
		return "/images/edits"
	case "videos.generations":
		return "/video/generations"
	default:
		return "/" + strings.ReplaceAll(request.Kind, ".", "/")
	}
}

func universalPostJSON(ctx context.Context, client *http.Client, baseURL string, endpoint string, body map[string]any, credentials map[string]any) (map[string]any, string, error) {
	raw, _ := json.Marshal(body)
	req, err := http.NewRequestWithContext(ctx, http.MethodPost, providerURL(baseURL, endpoint), bytes.NewReader(raw))
	if err != nil {
		return nil, "", err
	}
	req.Header.Set("Content-Type", "application/json")
	if apiKey := credential(credentials, "apiKey", "api_key", "key", "token"); apiKey != "" {
		req.Header.Set("Authorization", "Bearer "+apiKey)
	}
	resp, err := client.Do(req)
	if err != nil {
		return nil, "", &ClientError{Code: "network", Message: err.Error(), Retryable: true}
	}
	requestID := requestIDFromHTTPResponse(resp)
	result, err := decodeHTTPResponse(resp)
	return result, requestID, err
}

func universalGetJSON(ctx context.Context, client *http.Client, url string, credentials map[string]any) (map[string]any, string, error) {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
	if err != nil {
		return nil, "", err
	}
	if apiKey := credential(credentials, "apiKey", "api_key", "key", "token"); apiKey != "" {
		req.Header.Set("Authorization", "Bearer "+apiKey)
	}
	resp, err := client.Do(req)
	if err != nil {
		return nil, "", &ClientError{Code: "network", Message: err.Error(), Retryable: true}
	}
	requestID := requestIDFromHTTPResponse(resp)
	result, err := decodeHTTPResponse(resp)
	return result, requestID, err
}

func normalizeUniversalResult(request Request, result map[string]any, upstreamTaskID string) map[string]any {
	out := cloneMapAny(result)
	if out["created"] == nil {
		out["created"] = time.Now().UnixMilli()
	}
	if out["task_id"] == nil {
		out["task_id"] = upstreamTaskID
	}
	if out["upstream_task_id"] == nil {
		out["upstream_task_id"] = upstreamTaskID
	}
	if out["model"] == nil {
		out["model"] = request.Model
	}
	if out["status"] == nil {
		out["status"] = "success"
	}
	return out
}

func universalScriptError(err error) error {
	var scriptErr *scriptengine.Error
	if strings.TrimSpace(err.Error()) == "" {
		return &ClientError{Code: "script_error", Message: "script execution failed", Retryable: false}
	}
	if errors.As(err, &scriptErr) {
		return &ClientError{Code: scriptErr.ErrorCode(), Message: scriptErr.Error(), Retryable: scriptErr.ErrorCode() == "script_timeout"}
	}
	return &ClientError{Code: "script_error", Message: err.Error(), Retryable: false}
}

func universalFailureError(result map[string]any, requestID string, startedAt time.Time) error {
	message := firstNonEmptyString(result["message"], result["error"], result["error_message"], "universal task failed")
	return &ClientError{
		Code:               firstNonEmptyString(result["code"], result["error_code"], "provider_failed"),
		Message:            message,
		RequestID:          requestID,
		ResponseStartedAt:  startedAt,
		ResponseFinishedAt: time.Now(),
		ResponseDurationMS: responseDurationMS(startedAt, time.Now()),
		Retryable:          false,
	}
}

func isUniversalSuccess(result map[string]any) bool {
	switch universalStatus(result) {
	case "success", "succeeded", "completed", "complete", "done":
		return true
	default:
		return false
	}
}

func isUniversalFailure(result map[string]any) bool {
	switch universalStatus(result) {
	case "failed", "failure", "error", "cancelled", "canceled":
		return true
	default:
		return false
	}
}

func universalStatus(result map[string]any) string {
	return strings.ToLower(strings.TrimSpace(firstNonEmptyString(result["status"], result["state"], result["task_status"])))
}

func universalTaskID(result map[string]any) string {
	return firstNonEmptyString(result["upstream_task_id"], result["task_id"], result["taskId"], result["id"])
}

func universalProgress(request Request, upstreamTaskID string) []Progress {
	progress := providerProgress(request)
	progress = append(progress, Progress{Phase: "polling", Progress: 0.65, Message: "provider task polled", Payload: map[string]any{"upstreamTaskId": upstreamTaskID}})
	return progress
}

func universalStripPrivatePayload(payload map[string]any) map[string]any {
	out := cloneMapAny(payload)
	for _, key := range []string{"_originalParams", "_resolution", "_duration"} {
		delete(out, key)
	}
	return out
}

func universalSceneScript(config map[string]any, modelType string, keys ...string) string {
	for _, key := range keys {
		value := config[key]
		switch typed := value.(type) {
		case string:
			if strings.TrimSpace(typed) != "" {
				return strings.TrimSpace(typed)
			}
		case map[string]any:
			if script := firstNonEmptyString(typed[modelType], typed["common"]); script != "" {
				return script
			}
		}
	}
	return ""
}

func universalConfigString(config map[string]any, keys ...string) string {
	for _, key := range keys {
		if value := strings.TrimSpace(fmt.Sprint(config[key])); value != "" && value != "<nil>" {
			return value
		}
	}
	return ""
}

func universalDurationConfig(config map[string]any, fallback time.Duration, keys ...string) time.Duration {
	for _, key := range keys {
		switch value := config[key].(type) {
		case int:
			if value > 0 {
				return time.Duration(value) * time.Millisecond
			}
		case int64:
			if value > 0 {
				return time.Duration(value) * time.Millisecond
			}
		case float64:
			if value > 0 {
				return time.Duration(value) * time.Millisecond
			}
		case string:
			if parsed, err := time.ParseDuration(value); err == nil && parsed > 0 {
				return parsed
			}
		}
	}
	return fallback
}

func resolveUniversalTaskURL(config map[string]any, upstreamTaskID string) string {
	template := universalConfigString(config, "getTaskURL", "get_task_url")
	out := strings.TrimSpace(template)
	replacements := [][2]string{
		{"${upstream_task_id}", upstreamTaskID},
		{"{{upstream_task_id}}", upstreamTaskID},
		{"{upstream_task_id}", upstreamTaskID},
		{"${task_id}", upstreamTaskID},
		{"{{task_id}}", upstreamTaskID},
		{"{task_id}", upstreamTaskID},
		{"${taskId}", upstreamTaskID},
		{"${taskID}", upstreamTaskID},
		{"{{taskId}}", upstreamTaskID},
		{"{{taskID}}", upstreamTaskID},
		{"{taskId}", upstreamTaskID},
		{"{taskID}", upstreamTaskID},
	}
	for _, replacement := range replacements {
		out = strings.ReplaceAll(out, replacement[0], replacement[1])
	}
	return out
}