package convert

import (
	"encoding/json"
	"strings"
)

// ---------------------------------------------------------------------------
// 请求：Responses → Chat

// responsesToChatReq 将 OpenAI Responses 请求转为 Chat 请求。
func responsesToChatReq(body []byte) ([]byte, error) {
	var m map[string]json.RawMessage
	if err := json.Unmarshal(body, &m); err != nil {
		return nil, err
	}
	out := map[string]any{"model": str(rawJSON(m, "model"))}
	if v, ok := m["stream"]; ok && string(v) == "true" {
		out["stream"] = true
	}
	if v, ok := m["temperature"]; ok {
		out["temperature"] = v
	}
	if v, ok := m["top_p"]; ok {
		out["top_p"] = v
	}
	if v, ok := m["max_output_tokens"]; ok {
		out["max_tokens"] = v
	}

	var msgs []any
	if ins := str(rawJSON(m, "instructions")); ins != "" {
		msgs = append(msgs, map[string]any{"role": "system", "content": ins})
	}
	msgs = append(msgs, responsesInputToChat(rawJSON(m, "input"))...)
	out["messages"] = msgs

	if raw := rawJSON(m, "tools"); raw != nil {
		var tools []map[string]any
		if json.Unmarshal(raw, &tools) == nil {
			chatTools := make([]any, 0, len(tools))
			for _, t := range tools {
				chatTools = append(chatTools, map[string]any{
					"type": "function",
					"function": map[string]any{
						"name":        t["name"],
						"description": t["description"],
						"parameters":  t["parameters"],
					},
				})
			}
			out["tools"] = chatTools
		}
	}
	return json.Marshal(out)
}

// responsesInputToChat 把 Responses input 转成 Chat messages。
func responsesInputToChat(raw json.RawMessage) []any {
	if len(raw) == 0 || string(raw) == "null" {
		return nil
	}
	// 字符串输入
	if s := str(raw); s != "" {
		return []any{map[string]any{"role": "user", "content": s}}
	}
	var items []map[string]any
	if err := json.Unmarshal(raw, &items); err != nil || items == nil {
		return nil
	}
	var out []any
	for _, item := range items {
		switch item["type"] {
		case "function_call":
			var args any
			_ = json.Unmarshal([]byte(strField(item["arguments"])), &args)
			out = append(out, map[string]any{
				"role": "assistant",
				"content": "",
				"tool_calls": []any{map[string]any{
					"id":   strField(item["call_id"]),
					"type": "function",
					"function": map[string]any{
						"name":      strField(item["name"]),
						"arguments": strField(item["arguments"]),
					},
				}},
			})
		case "function_call_output":
			out = append(out, map[string]any{
				"role":         "tool",
				"tool_call_id": strField(item["call_id"]),
				"content":      strField(item["output"]),
			})
		default: // message 条目
			role, _ := item["role"].(string)
			if role == "" {
				role = "user"
			}
			if content, ok := item["content"].(string); ok {
				out = append(out, map[string]any{"role": role, "content": content})
			} else if blocks, ok := item["content"].([]any); ok {
				var text []string
				var contentBlocks []any
				for _, b := range blocks {
					bm, ok := b.(map[string]any)
					if !ok {
						continue
					}
					switch bm["type"] {
					case "input_text", "text":
						if t, _ := bm["text"].(string); t != "" {
							text = append(text, t)
							contentBlocks = append(contentBlocks, map[string]any{"type": "text", "text": t})
						}
					case "input_image":
						var url string
						if s, ok := bm["image_url"].(string); ok {
							url = s
						} else if m, ok := bm["image_url"].(map[string]any); ok {
							url, _ = m["url"].(string)
						}
						if url != "" {
							contentBlocks = append(contentBlocks, map[string]any{"type": "image_url", "image_url": map[string]any{"url": url}})
						}
					}
				}
				hasImage := false
				for _, cb := range contentBlocks {
					if m, _ := cb.(map[string]any); m["type"] == "image_url" {
						hasImage = true
						break
					}
				}
				if hasImage {
					out = append(out, map[string]any{"role": role, "content": contentBlocks})
				} else {
					out = append(out, map[string]any{"role": role, "content": strings.Join(text, "")})
				}
			}
		}
	}
	return out
}

// chatContentToResponsesBlocks 把 Chat 用户消息 content 转 Responses input 块数组（input_text / input_image）。
func chatContentToResponsesBlocks(content json.RawMessage) []any {
	// 纯字符串 → 单个 input_text
	var s string
	if json.Unmarshal(content, &s) == nil && s != "" {
		return []any{map[string]any{"type": "input_text", "text": s}}
	}
	// 数组 → 按块转换（text / image_url）
	var arr []map[string]any
	if json.Unmarshal(content, &arr) == nil && arr != nil {
		var out []any
		for _, b := range arr {
			switch b["type"] {
			case "text", "input_text":
				if t, _ := b["text"].(string); t != "" {
					out = append(out, map[string]any{"type": "input_text", "text": t})
				}
			case "image_url":
				var url string
				if iu, ok := b["image_url"].(map[string]any); ok {
					url, _ = iu["url"].(string)
				} else if s, ok := b["image_url"].(string); ok {
					url = s
				}
				if url != "" {
					out = append(out, map[string]any{"type": "input_image", "image_url": url})
				}
			}
		}
		return out
	}
	return nil
}

// ---------------------------------------------------------------------------
// 请求：Chat → Responses

// chatToResponsesReq 将 Chat 请求转为 Responses 请求。
func chatToResponsesReq(body []byte) ([]byte, error) {
	var req chatReq
	if err := json.Unmarshal(body, &req); err != nil {
		return nil, err
	}
	out := map[string]any{"model": req.Model}
	if req.Stream {
		out["stream"] = true
	}
	if req.Temperature != nil {
		out["temperature"] = *req.Temperature
	}
	if req.TopP != nil {
		out["top_p"] = *req.TopP
	}
	if req.MaxTokens != nil {
		out["max_output_tokens"] = *req.MaxTokens
	}

	var system []string
	var input []any
	for _, m := range req.Messages {
		if m.Role == "system" {
			if s := str(m.Content); s != "" {
				system = append(system, s)
			}
			continue
		}
		switch m.Role {
		case "tool":
			input = append(input, map[string]any{
				"type":   "function_call_output",
				"call_id": m.ToolCallID,
				"output": str(m.Content),
			})
		case "assistant":
			if len(m.ToolCalls) > 0 {
				for _, tc := range m.ToolCalls {
					input = append(input, map[string]any{
						"type":      "function_call",
						"call_id":   tc.ID,
						"name":      tc.Function.Name,
						"arguments": tc.Function.Arguments,
					})
				}
			} else if s := str(m.Content); s != "" {
				input = append(input, map[string]any{"type": "message", "role": "assistant", "content": []any{
					map[string]any{"type": "input_text", "text": s},
				}})
			}
		default:
			if blocks := chatContentToResponsesBlocks(m.Content); len(blocks) > 0 {
				input = append(input, map[string]any{"type": "message", "role": "user", "content": blocks})
			}
		}
	}
	if len(system) > 0 {
		out["instructions"] = strings.Join(system, "\n")
	}
	if len(input) == 1 {
		out["input"] = input[0] // 单条消息项
	} else {
		out["input"] = input
	}

	if len(req.Tools) > 0 {
		tools := make([]any, 0, len(req.Tools))
		for _, t := range req.Tools {
			tools = append(tools, map[string]any{
				"type":        "function",
				"name":        t.Function.Name,
				"description": t.Function.Description,
				"parameters":  rawOrObject(t.Function.Parameters),
			})
		}
		out["tools"] = tools
	}
	return json.Marshal(out)
}

// ---------------------------------------------------------------------------
// 响应：Responses → Chat

// responsesToChatResp 将 Responses 响应（非流式）转为 Chat 响应。
func responsesToChatResp(body []byte) ([]byte, error) {
	var m map[string]json.RawMessage
	if err := json.Unmarshal(body, &m); err != nil {
		return nil, err
	}
	var text string
	var toolCalls []any
	if raw := rawJSON(m, "output"); raw != nil {
		var outputs []map[string]any
		if json.Unmarshal(raw, &outputs) == nil {
			for _, o := range outputs {
				switch o["type"] {
				case "message":
					if content, ok := o["content"].([]any); ok {
						for _, c := range content {
							if cm, ok := c.(map[string]any); ok {
								if t, _ := cm["text"].(string); t != "" {
									text += t
								}
							}
						}
					}
				case "function_call":
					toolCalls = append(toolCalls, map[string]any{
						"id":   strField(o["call_id"]),
						"type": "function",
						"function": map[string]any{
							"name":      strField(o["name"]),
							"arguments": strField(o["arguments"]),
						},
					})
				}
			}
		}
	}
	msg := map[string]any{"role": "assistant", "content": text}
	if len(toolCalls) > 0 {
		msg["tool_calls"] = toolCalls
	}
	finish := "stop"
	switch {
	case string(rawJSON(m, "status")) == `"incomplete"`:
		finish = "length" // 截断优先，客户端可据此区分
	case len(toolCalls) > 0:
		finish = "tool_calls" // 有工具调用时映射 tool_calls，否则中转后 stop_reason 成 end_turn
	}
	var prompt, completion int64
	if u := rawJSON(m, "usage"); u != nil {
		var us struct {
			InputTokens  int64 `json:"input_tokens"`
			OutputTokens int64 `json:"output_tokens"`
		}
		_ = json.Unmarshal(u, &us)
		prompt, completion = us.InputTokens, us.OutputTokens
	}
	return json.Marshal(map[string]any{
		"id":      "chatcmpl-" + strings.TrimPrefix(str(rawJSON(m, "id")), "resp_"),
		"object":  "chat.completion",
		"model":   str(rawJSON(m, "model")),
		"choices": []any{map[string]any{"index": 0, "message": msg, "finish_reason": finish}},
		"usage": map[string]any{
			"prompt_tokens":     prompt,
			"completion_tokens": completion,
			"total_tokens":      prompt + completion,
		},
	})
}

// ---------------------------------------------------------------------------
// 响应：Chat → Responses

// chatToResponsesResp 将 Chat 响应（非流式）转为 Responses 响应。
func chatToResponsesResp(body []byte) ([]byte, error) {
	var r chatResp
	if err := json.Unmarshal(body, &r); err != nil {
		return nil, err
	}
	output := make([]any, 0, 2)
	var finish = "completed"
	if len(r.Choices) > 0 {
		msg := r.Choices[0].Message
		if msg.Content != "" {
			output = append(output, map[string]any{
				"type":    "message",
				"role":    "assistant",
				"content": []any{map[string]any{"type": "output_text", "text": msg.Content}},
			})
		}
		for _, tc := range msg.ToolCalls {
			output = append(output, map[string]any{
				"type":      "function_call",
				"call_id":   tc.ID,
				"name":      tc.Function.Name,
				"arguments": tc.Function.Arguments,
			})
		}
		if r.Choices[0].FinishReason == "length" {
			finish = "incomplete"
		}
	}
	status := finish
	return json.Marshal(map[string]any{
		"id":      "resp_" + strings.TrimPrefix(r.ID, "chatcmpl-"),
		"object":  "response",
		"model":   r.Model,
		"status":  status,
		"output":  output,
		"usage": map[string]any{
			"input_tokens":  r.Usage.PromptTokens,
			"output_tokens": r.Usage.CompletionTokens,
			"total_tokens":  r.Usage.PromptTokens + r.Usage.CompletionTokens,
		},
	})
}