package convert

import (
	"encoding/json"
	"errors"

	"openteam/server/internal/proxy/openai"
)

// responsesInputToChat converts Responses API input items into chat messages.
func responsesInputToChat(raw json.RawMessage) ([]openai.ChatMessage, error) {
	var msgs []openai.ChatMessage

	// `input` may be a plain string.
	var s string
	if json.Unmarshal(raw, &s) == nil {
		content, _ := json.Marshal(s)
		msgs = append(msgs, openai.ChatMessage{Role: "user", Content: content})
		return msgs, nil
	}

	// Or an array of content parts (text/image).
	var parts []map[string]json.RawMessage
	if json.Unmarshal(raw, &parts) == nil {
		chat, err := contentPartsToChat(parts)
		if err == nil {
			return chat, nil
		}
	}

	var items []map[string]json.RawMessage
	if err := json.Unmarshal(raw, &items); err != nil {
		return nil, err
	}
	for _, item := range items {
		var typ string
		_ = json.Unmarshal(item["type"], &typ)
		switch typ {
		case "message":
			var role string
			_ = json.Unmarshal(item["role"], &role)
			content, err := contentPartsToText(item["content"])
			if err != nil {
				continue
			}
			msgs = append(msgs, openai.ChatMessage{Role: role, Content: content})
		case "function_call":
			tc := map[string]any{
				"id":   rawString(item["call_id"]),
				"type": "function",
				"function": map[string]any{
					"name":      rawString(item["name"]),
					"arguments": rawString(item["arguments"]),
				},
			}
			tcArr, _ := json.Marshal([]any{tc})
			msgs = append(msgs, openai.ChatMessage{Role: "assistant", ToolCalls: tcArr})
		case "function_call_output":
			content, _ := json.Marshal(rawString(item["output"]))
			msgs = append(msgs, openai.ChatMessage{Role: "tool", ToolCallID: rawString(item["call_id"]), Content: content})
		case "reasoning", "computer_call", "web_search_call":
			// Not representable in chat; drop.
		}
	}
	if len(msgs) == 0 {
		content, _ := json.Marshal("")
		msgs = append(msgs, openai.ChatMessage{Role: "user", Content: content})
	}
	return msgs, nil
}

// contentPartsToText flattens an array of content parts into a string.
func contentPartsToText(raw json.RawMessage) (json.RawMessage, error) {
	var parts []map[string]json.RawMessage
	if err := json.Unmarshal(raw, &parts); err != nil {
		var s string
		if err := json.Unmarshal(raw, &s); err == nil {
			c, _ := json.Marshal(s)
			return c, nil
		}
		return nil, err
	}
	var buf string
	for _, p := range parts {
		var typ string
		_ = json.Unmarshal(p["type"], &typ)
		switch typ {
		case "input_text", "output_text", "text":
			buf += rawString(p["text"])
		}
	}
	c, _ := json.Marshal(buf)
	return c, nil
}

func contentPartsToChat(parts []map[string]json.RawMessage) ([]openai.ChatMessage, error) {
	out := []map[string]any{}
	for _, p := range parts {
		var typ string
		_ = json.Unmarshal(p["type"], &typ)
		switch typ {
		case "input_text", "output_text", "text":
			out = append(out, map[string]any{"type": "text", "text": rawString(p["text"])})
		case "input_image":
			out = append(out, map[string]any{
				"type": "image_url",
				"image_url": map[string]any{
					"url": "data:" + rawString(p["media_type"]) + ";base64," + rawString(p["image_url"]),
				},
			})
		}
	}
	if len(out) == 0 {
		return nil, jsonError("empty content")
	}
	arr, _ := json.Marshal(out)
	msg := openai.ChatMessage{Role: "user", Content: arr}
	return []openai.ChatMessage{msg}, nil
}

// chatToResponsesOutput builds Responses output items from a chat completion.
func chatToResponsesOutput(cc *openai.ChatCompletion) ([]map[string]any, string) {
	var items []map[string]any
	var status = "completed"
	if len(cc.Choices) == 0 {
		return items, status
	}
	ch := cc.Choices[0]
	if ch.FinishReason == "length" {
		status = "incomplete"
	}
	content := []map[string]any{}
	if text := contentString(ch.Message.Content); text != "" {
		content = append(content, map[string]any{"type": "output_text", "text": text})
	}
	items = append(items, map[string]any{"type": "message", "role": "assistant", "content": content})
	if len(ch.Message.ToolCalls) > 0 {
		var calls []struct {
			ID       string `json:"id"`
			Function struct {
				Name      string          `json:"name"`
				Arguments json.RawMessage `json:"arguments"`
			} `json:"function"`
		}
		if json.Unmarshal(ch.Message.ToolCalls, &calls) == nil {
			for _, call := range calls {
				items = append(items, map[string]any{
					"type":      "function_call",
					"call_id":   call.ID,
					"name":      call.Function.Name,
					"arguments": rawString(call.Function.Arguments),
				})
			}
		}
	}
	return items, status
}

func jsonError(msg string) error {
	return errors.New(msg)
}