package services

import (
	"bytes"
	"github.com/libaxuan/cursor2api-go/models"
	"encoding/json"
	"fmt"
	"strings"
)

// ResponseToolAdapter records tool mappings for Responses API bridging.
type ResponseToolAdapter struct {
	ToolTypesByName  map[string]string
	ShellEnvironment interface{}
}

// BuildChatCompletionRequestFromResponse converts a Responses API request into a chat/completions request.
func BuildChatCompletionRequestFromResponse(req *models.ResponseRequest) (*models.ChatCompletionRequest, *ResponseToolAdapter, error) {
	instructionMessages, err := parseResponseMessages(req.Instructions, "system")
	if err != nil {
		return nil, nil, err
	}

	inputMessages, err := parseResponseMessages(req.Input, "user")
	if err != nil {
		return nil, nil, err
	}

	messages := append(instructionMessages, inputMessages...)
	if len(messages) == 0 {
		return nil, nil, fmt.Errorf("input is required")
	}

	tools, adapter, err := convertResponseTools(req.Tools)
	if err != nil {
		return nil, nil, err
	}

	toolChoice, err := convertResponseToolChoice(req.ToolChoice)
	if err != nil {
		return nil, nil, err
	}

	chatReq := &models.ChatCompletionRequest{
		Model:       req.Model,
		Messages:    messages,
		Stream:      req.Stream,
		Temperature: req.Temperature,
		MaxTokens:   req.MaxOutputTokens,
		TopP:        req.TopP,
		Tools:       tools,
		ToolChoice:  toolChoice,
	}

	if req.User != nil {
		chatReq.User = *req.User
	}

	return chatReq, adapter, nil
}

func parseResponseMessages(raw json.RawMessage, defaultRole string) ([]models.Message, error) {
	trimmed := bytes.TrimSpace(raw)
	if len(trimmed) == 0 || string(trimmed) == "null" {
		return nil, nil
	}

	switch trimmed[0] {
	case '"':
		var text string
		if err := json.Unmarshal(trimmed, &text); err != nil {
			return nil, fmt.Errorf("invalid input text: %w", err)
		}
		if strings.TrimSpace(text) == "" {
			return nil, nil
		}
		return []models.Message{{Role: defaultRole, Content: text}}, nil
	case '{':
		var obj map[string]interface{}
		if err := json.Unmarshal(trimmed, &obj); err != nil {
			return nil, fmt.Errorf("invalid input object: %w", err)
		}
		msgs := parseResponseItem(obj, defaultRole)
		return msgs, nil
	case '[':
		var arr []interface{}
		if err := json.Unmarshal(trimmed, &arr); err != nil {
			return nil, fmt.Errorf("invalid input array: %w", err)
		}
		var result []models.Message
		for _, item := range arr {
			switch typed := item.(type) {
			case map[string]interface{}:
				result = append(result, parseResponseItem(typed, defaultRole)...)
			case string:
				if strings.TrimSpace(typed) != "" {
					result = append(result, models.Message{Role: defaultRole, Content: typed})
				}
			}
		}
		return result, nil
	default:
		return nil, fmt.Errorf("unsupported input format")
	}
}

func parseResponseItem(item map[string]interface{}, defaultRole string) []models.Message {
	itemType := strings.TrimSpace(asString(item["type"]))
	role := strings.TrimSpace(asString(item["role"]))

	if itemType == "" && role != "" {
		itemType = "message"
	}

	switch itemType {
	case "message":
		if role == "" {
			role = defaultRole
		}
		role = mapRole(role)
		content := extractContentText(item["content"])
		if strings.TrimSpace(content) == "" {
			return nil
		}
		return []models.Message{{Role: role, Content: content}}
	case "function_call":
		callID := firstNonEmpty(asString(item["call_id"]), asString(item["id"]))
		name := strings.TrimSpace(asString(item["name"]))
		args := strings.TrimSpace(stringifyJSON(item["arguments"]))
		if args == "" {
			args = "{}"
		}
		toolCall := models.ToolCall{
			ID:   callID,
			Type: "function",
			Function: models.FunctionCall{
				Name:      name,
				Arguments: args,
			},
		}
		return []models.Message{{Role: "assistant", ToolCalls: []models.ToolCall{toolCall}}}
	case "tool_call":
		callID := firstNonEmpty(asString(item["call_id"]), asString(item["id"]))
		name := strings.TrimSpace(asString(item["tool_name"]))
		if name == "" {
			name = strings.TrimSpace(asString(item["name"]))
		}
		if name == "" {
			return nil
		}
		args := strings.TrimSpace(stringifyJSON(item["arguments"]))
		if args == "" {
			if action, ok := item["action"]; ok {
				args = wrapJSONArg("action", action)
			} else if input := strings.TrimSpace(asString(item["input"])); input != "" {
				args = wrapInputAsJSON(input)
			} else {
				args = "{}"
			}
		}
		toolCall := models.ToolCall{
			ID:   callID,
			Type: "function",
			Function: models.FunctionCall{
				Name:      name,
				Arguments: args,
			},
		}
		return []models.Message{{Role: "assistant", ToolCalls: []models.ToolCall{toolCall}}}
	case "custom_tool_call":
		callID := firstNonEmpty(asString(item["call_id"]), asString(item["id"]))
		name := strings.TrimSpace(asString(item["name"]))
		input := asString(item["input"])
		args := wrapInputAsJSON(input)
		toolCall := models.ToolCall{
			ID:   callID,
			Type: "function",
			Function: models.FunctionCall{
				Name:      name,
				Arguments: args,
			},
		}
		return []models.Message{{Role: "assistant", ToolCalls: []models.ToolCall{toolCall}}}
	case "apply_patch_call":
		callID := firstNonEmpty(asString(item["call_id"]), asString(item["id"]))
		op := item["operation"]
		args := wrapJSONArg("operation", op)
		toolCall := models.ToolCall{
			ID:   callID,
			Type: "function",
			Function: models.FunctionCall{
				Name:      "apply_patch",
				Arguments: args,
			},
		}
		return []models.Message{{Role: "assistant", ToolCalls: []models.ToolCall{toolCall}}}
	case "shell_call":
		callID := firstNonEmpty(asString(item["call_id"]), asString(item["id"]))
		action := item["action"]
		args := wrapJSONArg("action", action)
		toolCall := models.ToolCall{
			ID:   callID,
			Type: "function",
			Function: models.FunctionCall{
				Name:      "shell",
				Arguments: args,
			},
		}
		return []models.Message{{Role: "assistant", ToolCalls: []models.ToolCall{toolCall}}}
	case "local_shell_call":
		callID := firstNonEmpty(asString(item["call_id"]), asString(item["id"]))
		action := item["action"]
		args := ""
		if action != nil {
			args = wrapJSONArg("action", action)
		}
		if args == "" {
			args = strings.TrimSpace(stringifyJSON(item["arguments"]))
		}
		if args == "" {
			args = "{}"
		}
		toolCall := models.ToolCall{
			ID:   callID,
			Type: "function",
			Function: models.FunctionCall{
				Name:      "local_shell",
				Arguments: args,
			},
		}
		return []models.Message{{Role: "assistant", ToolCalls: []models.ToolCall{toolCall}}}
	case "function_call_output":
		callID := asString(item["call_id"])
		output := normalizeToolOutput(item["output"])
		if strings.TrimSpace(output) == "" {
			return nil
		}
		return []models.Message{{Role: "tool", Content: output, ToolCallID: callID}}
	case "apply_patch_call_output":
		callID := asString(item["call_id"])
		output := normalizeToolOutput(item["output"])
		if strings.TrimSpace(output) == "" {
			return nil
		}
		return []models.Message{{Role: "tool", Content: output, ToolCallID: callID, Name: "apply_patch"}}
	case "shell_call_output":
		callID := asString(item["call_id"])
		output := normalizeToolOutput(item["output"])
		if strings.TrimSpace(output) == "" {
			return nil
		}
		return []models.Message{{Role: "tool", Content: output, ToolCallID: callID, Name: "shell"}}
	case "local_shell_call_output":
		callID := asString(item["call_id"])
		output := normalizeToolOutput(item["output"])
		if strings.TrimSpace(output) == "" {
			return nil
		}
		return []models.Message{{Role: "tool", Content: output, ToolCallID: callID, Name: "local_shell"}}
	case "tool_call_output":
		callID := asString(item["call_id"])
		output := normalizeToolOutput(item["output"])
		if strings.TrimSpace(output) == "" {
			return nil
		}
		name := strings.TrimSpace(asString(item["tool_name"]))
		if name == "" {
			name = strings.TrimSpace(asString(item["name"]))
		}
		return []models.Message{{Role: "tool", Content: output, ToolCallID: callID, Name: name}}
	default:
		return nil
	}
}

func convertResponseTools(rawTools []map[string]interface{}) ([]models.Tool, *ResponseToolAdapter, error) {
	adapter := &ResponseToolAdapter{ToolTypesByName: make(map[string]string)}
	tools := make([]models.Tool, 0, len(rawTools))

	for _, raw := range rawTools {
		toolType := strings.TrimSpace(asString(raw["type"]))
		if toolType == "" {
			continue
		}

		switch toolType {
		case "function":
			name := strings.TrimSpace(asString(raw["name"]))
			if name == "" {
				return nil, nil, fmt.Errorf("function tool name is required")
			}
			desc := strings.TrimSpace(asString(raw["description"]))
			params, _ := raw["parameters"].(map[string]interface{})
			tools = append(tools, models.Tool{
				Type: "function",
				Function: models.FunctionDefinition{
					Name:        name,
					Description: desc,
					Parameters:  params,
				},
			})
		case "apply_patch":
			tools = append(tools, applyPatchToolDefinition())
			adapter.ToolTypesByName["apply_patch"] = "apply_patch"
		case "shell":
			tools = append(tools, shellToolDefinition())
			adapter.ToolTypesByName["shell"] = "shell"
			if env, ok := raw["environment"]; ok {
				adapter.ShellEnvironment = env
			}
		case "local_shell":
			tools = append(tools, localShellToolDefinition())
			adapter.ToolTypesByName["local_shell"] = "local_shell"
		default:
			// Fallback: expose built-in tools as custom function tools for compatibility.
			name := toolType
			desc := strings.TrimSpace(asString(raw["description"]))
			if desc == "" {
				desc = fmt.Sprintf("Built-in tool: %s (proxied).", toolType)
			}
			tools = append(tools, models.Tool{
				Type: "function",
				Function: models.FunctionDefinition{
					Name:        name,
					Description: desc,
					Parameters: map[string]interface{}{
						"type":                 "object",
						"additionalProperties": true,
					},
				},
			})
		}
	}

	return tools, adapter, nil
}

func applyPatchToolDefinition() models.Tool {
	return models.Tool{
		Type: "function",
		Function: models.FunctionDefinition{
			Name:        "apply_patch",
			Description: "Apply a patch to the local workspace. Return JSON with operation {type, path, diff}.",
			Parameters: map[string]interface{}{
				"type": "object",
				"properties": map[string]interface{}{
					"operation": map[string]interface{}{
						"type": "object",
						"properties": map[string]interface{}{
							"type": map[string]interface{}{
								"type": "string",
								"enum": []string{"create_file", "update_file", "delete_file"},
							},
							"path": map[string]interface{}{
								"type": "string",
							},
							"diff": map[string]interface{}{
								"type": "string",
							},
						},
						"required": []string{"type", "path"},
					},
				},
				"required": []string{"operation"},
			},
		},
	}
}

func shellToolDefinition() models.Tool {
	return models.Tool{
		Type: "function",
		Function: models.FunctionDefinition{
			Name:        "shell",
			Description: "Run shell commands locally. Return JSON with commands (array), timeout_ms, max_output_length.",
			Parameters: map[string]interface{}{
				"type": "object",
				"properties": map[string]interface{}{
					"commands": map[string]interface{}{
						"type":  "array",
						"items": map[string]interface{}{"type": "string"},
					},
					"timeout_ms": map[string]interface{}{
						"type": "integer",
					},
					"max_output_length": map[string]interface{}{
						"type": "integer",
					},
					"action": map[string]interface{}{
						"type": "object",
						"properties": map[string]interface{}{
							"commands": map[string]interface{}{
								"type":  "array",
								"items": map[string]interface{}{"type": "string"},
							},
							"timeout_ms": map[string]interface{}{
								"type": "integer",
							},
							"max_output_length": map[string]interface{}{
								"type": "integer",
							},
						},
					},
				},
			},
		},
	}
}

func localShellToolDefinition() models.Tool {
	return models.Tool{
		Type: "function",
		Function: models.FunctionDefinition{
			Name:        "local_shell",
			Description: "Run local shell commands. Return JSON with command, timeout_ms, working_directory, env, max_output_length.",
			Parameters: map[string]interface{}{
				"type": "object",
				"properties": map[string]interface{}{
					"command": map[string]interface{}{
						"type": "string",
					},
					"commands": map[string]interface{}{
						"type":  "array",
						"items": map[string]interface{}{"type": "string"},
					},
					"timeout_ms": map[string]interface{}{
						"type": "integer",
					},
					"working_directory": map[string]interface{}{
						"type": "string",
					},
					"env": map[string]interface{}{
						"type":                 "object",
						"additionalProperties": true,
					},
					"max_output_length": map[string]interface{}{
						"type": "integer",
					},
					"action": map[string]interface{}{
						"type": "object",
						"properties": map[string]interface{}{
							"command": map[string]interface{}{
								"type": "string",
							},
							"commands": map[string]interface{}{
								"type":  "array",
								"items": map[string]interface{}{"type": "string"},
							},
							"timeout_ms": map[string]interface{}{
								"type": "integer",
							},
							"working_directory": map[string]interface{}{
								"type": "string",
							},
							"env": map[string]interface{}{
								"type":                 "object",
								"additionalProperties": true,
							},
							"max_output_length": map[string]interface{}{
								"type": "integer",
							},
						},
					},
				},
			},
		},
	}
}

func convertResponseToolChoice(raw json.RawMessage) (json.RawMessage, error) {
	trimmed := bytes.TrimSpace(raw)
	if len(trimmed) == 0 || string(trimmed) == "null" {
		return nil, nil
	}

	var choiceString string
	if err := json.Unmarshal(trimmed, &choiceString); err == nil {
		switch choiceString {
		case "auto", "none", "required":
			return trimmed, nil
		default:
			return nil, fmt.Errorf("unsupported tool_choice value %q", choiceString)
		}
	}

	var choiceObj map[string]interface{}
	if err := json.Unmarshal(trimmed, &choiceObj); err != nil {
		return nil, fmt.Errorf("tool_choice must be a string or object")
	}

	choiceType := strings.TrimSpace(asString(choiceObj["type"]))
	switch choiceType {
	case "function", "custom":
		name := strings.TrimSpace(asString(choiceObj["name"]))
		if name == "" {
			return nil, fmt.Errorf("tool_choice.name is required")
		}
		return json.Marshal(models.ToolChoiceObject{
			Type: "function",
			Function: &models.ToolChoiceFunction{
				Name: name,
			},
		})
	case "apply_patch":
		return json.Marshal(models.ToolChoiceObject{
			Type: "function",
			Function: &models.ToolChoiceFunction{
				Name: "apply_patch",
			},
		})
	case "shell":
		return json.Marshal(models.ToolChoiceObject{
			Type: "function",
			Function: &models.ToolChoiceFunction{
				Name: "shell",
			},
		})
	case "local_shell":
		return json.Marshal(models.ToolChoiceObject{
			Type: "function",
			Function: &models.ToolChoiceFunction{
				Name: "local_shell",
			},
		})
	default:
		return nil, fmt.Errorf("unsupported tool_choice type %q", choiceType)
	}
}

func extractContentText(content interface{}) string {
	switch v := content.(type) {
	case string:
		return v
	case []interface{}:
		var b strings.Builder
		for _, part := range v {
			if partMap, ok := part.(map[string]interface{}); ok {
				partType := strings.TrimSpace(asString(partMap["type"]))
				switch partType {
				case "input_text", "output_text", "text":
					b.WriteString(asString(partMap["text"]))
				case "refusal":
					b.WriteString(asString(partMap["refusal"]))
				}
			}
		}
		return b.String()
	case map[string]interface{}:
		partType := strings.TrimSpace(asString(v["type"]))
		switch partType {
		case "input_text", "output_text", "text":
			return asString(v["text"])
		case "refusal":
			return asString(v["refusal"])
		}
	}

	if data, err := json.Marshal(content); err == nil {
		return string(data)
	}
	return ""
}

func normalizeToolOutput(output interface{}) string {
	switch v := output.(type) {
	case string:
		return v
	case []interface{}:
		var b strings.Builder
		for _, part := range v {
			if partMap, ok := part.(map[string]interface{}); ok {
				partType := strings.TrimSpace(asString(partMap["type"]))
				switch partType {
				case "output_text", "input_text", "text":
					b.WriteString(asString(partMap["text"]))
				case "refusal":
					b.WriteString(asString(partMap["refusal"]))
				default:
					if data, err := json.Marshal(partMap); err == nil {
						b.WriteString(string(data))
					}
				}
			}
		}
		if b.Len() > 0 {
			return b.String()
		}
	case map[string]interface{}:
		if data, err := json.Marshal(v); err == nil {
			return string(data)
		}
	}

	if data, err := json.Marshal(output); err == nil {
		return string(data)
	}
	return ""
}

func wrapInputAsJSON(input string) string {
	payload := map[string]interface{}{
		"input": input,
	}
	if data, err := json.Marshal(payload); err == nil {
		return string(data)
	}
	return "{}"
}

func wrapJSONArg(key string, value interface{}) string {
	payload := map[string]interface{}{
		key: value,
	}
	if data, err := json.Marshal(payload); err == nil {
		return string(data)
	}
	return "{}"
}

func stringifyJSON(value interface{}) string {
	switch v := value.(type) {
	case string:
		return v
	case json.RawMessage:
		return string(v)
	default:
		if data, err := json.Marshal(v); err == nil {
			return string(data)
		}
	}
	return ""
}

func asString(value interface{}) string {
	switch v := value.(type) {
	case string:
		return v
	case json.Number:
		return v.String()
	}
	return ""
}

func firstNonEmpty(values ...string) string {
	for _, v := range values {
		if strings.TrimSpace(v) != "" {
			return v
		}
	}
	return ""
}

func mapRole(role string) string {
	role = strings.ToLower(strings.TrimSpace(role))
	switch role {
	case "developer":
		return "system"
	default:
		if role == "" {
			return "user"
		}
		return role
	}
}