package runner

import (
	"context"
	"fmt"
	"reflect"
	"strings"

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

func (s *Service) preprocessRequestWithScripts(ctx context.Context, kind string, body map[string]any, candidate store.RuntimeModelCandidate) parameterPreprocessResult {
	if platformConfigBool(candidate.PlatformConfig, "skipParamNormalization", "skip_param_normalization") {
		modelType := strings.TrimSpace(candidate.ModelType)
		if modelType == "" {
			modelType = modelTypeFromKind(kind, body)
		}
		input := cloneMap(body)
		return parameterPreprocessResult{
			Body: cloneMap(body),
			Log: parameterPreprocessingLog{
				ModelType: modelType,
				Input:     input,
				Output:    cloneMap(body),
				Changed:   false,
				Changes:   []parameterPreprocessChange{},
				Model:     preprocessingModelSnapshot(candidate),
			},
		}
	}

	result := preprocessRequestWithLog(kind, body, candidate)
	if result.Err != nil {
		return result
	}
	scriptText := platformConfigString(candidate.PlatformConfig, "customPreprocessScript", "custom_preprocess_script")
	if strings.TrimSpace(scriptText) == "" || s.scriptExecutor == nil {
		return result
	}

	before := cloneMap(result.Body)
	scriptContext := s.scriptContext(candidate, result.Log.ModelType, nil, map[string]any{
		"modelCapability": effectiveModelCapability(candidate),
		"platformModel":   result.Log.Model,
		"platform":        candidate.PlatformConfig,
	})
	out, err := s.scriptExecutor.Execute(ctx, scriptengine.Options{
		Script:              scriptText,
		Args:                []any{cloneMap(result.Body), result.Log.ModelType, scriptContext},
		ContextData:         scriptContext,
		ScriptName:          "custom_preprocess_script:" + result.Log.ModelType,
		PreferredEntryNames: []string{"preprocessParams", "preprocess", "main", "handler"},
		Timeout:             scriptengine.PreprocessTimeout,
	})
	if err != nil {
		result.Log.recordScriptChange("CustomPreprocessScript", "error", "$", before, result.Body, err.Error())
		result.Log.Output = cloneMap(result.Body)
		result.Log.Changed = len(result.Log.Changes) > 0
		result.Err = err
		return result
	}
	rewritten, ok := out.(map[string]any)
	if !ok || rewritten == nil {
		result.Log.Output = cloneMap(result.Body)
		result.Log.Changed = len(result.Log.Changes) > 0
		return result
	}
	merged := cloneMap(result.Body)
	for key, value := range rewritten {
		merged[key] = value
	}
	if !mapsEqual(before, merged) {
		result.Log.recordScriptChange("CustomPreprocessScript", "rewrite", "$", before, merged, "platform custom preprocess script returned parameter updates")
	}
	result.Body = merged
	result.Log.Output = cloneMap(merged)
	result.Log.Changed = len(result.Log.Changes) > 0
	return result
}

func (s *Service) scriptContext(candidate store.RuntimeModelCandidate, modelType string, payload map[string]any, extra map[string]any) map[string]any {
	getTaskURL := platformConfigString(candidate.PlatformConfig, "getTaskURL", "get_task_url")
	baseURL := strings.TrimRight(strings.TrimSpace(candidate.BaseURL), "/")
	env := cloneMap(candidate.PlatformConfig)
	context := map[string]any{
		"__easyaiScriptContext": true,
		"baseURL":               baseURL,
		"getTaskURL":            getTaskURL,
		"authValues":            cloneMap(candidate.Credentials),
		"headers":               map[string]any{},
		"payload":               cloneMap(payload),
		"type":                  modelType,
		"options": map[string]any{
			"model":              candidate.ModelName,
			"providerModelName":  candidate.ProviderModelName,
			"platformId":         candidate.PlatformID,
			"platformModelId":    candidate.PlatformModelID,
			"canonicalModelKey":  candidate.CanonicalModelKey,
			"sourceProviderCode": candidate.Provider,
		},
		"env":       env,
		"candidate": preprocessingModelSnapshot(candidate),
	}
	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 resolveTaskURLTemplate(getTaskURL, taskID, "")
	}
	for key, value := range extra {
		context[key] = value
	}
	return context
}

func preprocessingModelSnapshot(candidate store.RuntimeModelCandidate) map[string]any {
	return map[string]any{
		"modelName":         candidate.ModelName,
		"modelAlias":        candidate.ModelAlias,
		"providerModelName": candidate.ProviderModelName,
		"provider":          candidate.Provider,
		"platformId":        candidate.PlatformID,
		"platformModelId":   candidate.PlatformModelID,
		"capabilities":      cloneMap(candidate.Capabilities),
	}
}

func (log *parameterPreprocessingLog) recordScriptChange(processor string, action string, path string, before any, after any, reason string) {
	if log == nil {
		return
	}
	log.Changes = append(log.Changes, parameterPreprocessChange{
		Processor: processor,
		Action:    action,
		Path:      path,
		Before:    cloneAny(before),
		After:     cloneAny(after),
		Reason:    reason,
	})
}

func platformConfigString(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 platformConfigBool(config map[string]any, keys ...string) bool {
	for _, key := range keys {
		switch value := config[key].(type) {
		case bool:
			return value
		case string:
			return strings.EqualFold(strings.TrimSpace(value), "true")
		}
	}
	return false
}

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

func mapsEqual(left map[string]any, right map[string]any) bool {
	return reflect.DeepEqual(left, right)
}