package service

import (
	"context"
	"fmt"
	"testing"

	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"

	"github.com/gochat/gochat/internal/llm"
)

// ========== Streaming Tests (M12) ==========

func TestCaptainTaskService_ReplySuggestionStream_成功(t *testing.T) {
	db, mockProvider, svc := setupCaptainTaskService(t)
	account := createTestAccount(t, db)
	assistant := createTestAssistant(t, db, account.ID, "客服助手")
	conv := createTestConversationWithMessages(t, db, account.ID, []struct{ sender, content string }{
		{"contact", "你们的产品怎么使用？"},
		{"agent", "请问是哪个产品？"},
	})

	mockProvider.embeddingResponse = makeEmbeddingResponse()
	mockProvider.streamChunks = []llm.StreamChunk{
		{Choices: []llm.StreamChoice{{Delta: llm.StreamDelta{Content: "建议一"}, FinishReason: ""}}},
		{Choices: []llm.StreamChoice{{Delta: llm.StreamDelta{Content: "建议二"}, FinishReason: "stop"}}},
	}

	var collected []string
	err := svc.ReplySuggestionStream(context.Background(), account.ID, &TaskReplySuggestionRequest{
		AssistantID:    assistant.ID,
		ConversationID: conv.ID,
		Tone:           "friendly",
	}, func(chunk llm.StreamChunk) error {
		if len(chunk.Choices) > 0 && chunk.Choices[0].Delta.Content != "" {
			collected = append(collected, chunk.Choices[0].Delta.Content)
		}
		return nil
	})

	require.NoError(t, err)
	assert.Len(t, collected, 2)
	assert.Equal(t, "建议一", collected[0])
	assert.Equal(t, "建议二", collected[1])
}

func TestCaptainTaskService_ReplySuggestionStream_助手不存在(t *testing.T) {
	_, _, svc := setupCaptainTaskService(t)

	err := svc.ReplySuggestionStream(context.Background(), 1, &TaskReplySuggestionRequest{
		AssistantID:    99999,
		ConversationID: 1,
	}, func(chunk llm.StreamChunk) error {
		return nil
	})

	assert.Error(t, err)
	assert.Contains(t, err.Error(), "assistant not found")
}

func TestCaptainTaskService_ReplySuggestionStream_LLM流错误(t *testing.T) {
	db, mockProvider, svc := setupCaptainTaskService(t)
	account := createTestAccount(t, db)
	assistant := createTestAssistant(t, db, account.ID, "助手")
	conv := createTestConversationWithMessages(t, db, account.ID, []struct{ sender, content string }{
		{"contact", "hello"},
	})

	mockProvider.embeddingResponse = makeEmbeddingResponse()
	mockProvider.streamError = fmt.Errorf("LLM stream 调用超时")

	err := svc.ReplySuggestionStream(context.Background(), account.ID, &TaskReplySuggestionRequest{
		AssistantID:    assistant.ID,
		ConversationID: conv.ID,
	}, func(chunk llm.StreamChunk) error {
		return nil
	})

	assert.Error(t, err)
	assert.Contains(t, err.Error(), "LLM stream")
}

func TestCaptainTaskService_SummarizeStream_成功(t *testing.T) {
	db, mockProvider, svc := setupCaptainTaskService(t)
	account := createTestAccount(t, db)
	conv := createTestConversationWithMessages(t, db, account.ID, []struct{ sender, content string }{
		{"contact", "你好，我的订单还没收到"},
		{"agent", "我来帮您查询一下"},
	})

	mockProvider.streamChunks = []llm.StreamChunk{
		{Choices: []llm.StreamChoice{{Delta: llm.StreamDelta{Content: "客户咨询订单"}, FinishReason: ""}}},
		{Choices: []llm.StreamChoice{{Delta: llm.StreamDelta{Content: "状态查询"}, FinishReason: "stop"}}},
	}

	var collected []string
	err := svc.SummarizeStream(context.Background(), account.ID, &TaskSummarizeRequest{
		ConversationID: conv.ID,
		Language:       "zh-CN",
	}, func(chunk llm.StreamChunk) error {
		if len(chunk.Choices) > 0 && chunk.Choices[0].Delta.Content != "" {
			collected = append(collected, chunk.Choices[0].Delta.Content)
		}
		return nil
	})

	require.NoError(t, err)
	assert.Len(t, collected, 2)
}

func TestCaptainTaskService_SummarizeStream_无消息(t *testing.T) {
	db, mockProvider, svc := setupCaptainTaskService(t)
	account := createTestAccount(t, db)
	conv := createTestConversationWithMessages(t, db, account.ID, nil)

	// When no messages, SummarizeStream still proceeds with empty context
	// It won't return an error, but the LLM will receive minimal context
	mockProvider.streamChunks = []llm.StreamChunk{
		{Choices: []llm.StreamChoice{{Delta: llm.StreamDelta{Content: "no content"}}}},
	}

	var collected []string
	err := svc.SummarizeStream(context.Background(), account.ID, &TaskSummarizeRequest{
		ConversationID: conv.ID,
	}, func(chunk llm.StreamChunk) error {
		if len(chunk.Choices) > 0 && chunk.Choices[0].Delta.Content != "" {
			collected = append(collected, chunk.Choices[0].Delta.Content)
		}
		return nil
	})

	require.NoError(t, err)
	assert.NotEmpty(t, collected)
}

func TestCaptainTaskService_SummarizeStream_LLM流错误(t *testing.T) {
	db, mockProvider, svc := setupCaptainTaskService(t)
	account := createTestAccount(t, db)
	conv := createTestConversationWithMessages(t, db, account.ID, []struct{ sender, content string }{
		{"contact", "test message"},
	})

	mockProvider.streamError = fmt.Errorf("LLM stream 服务不可用")

	err := svc.SummarizeStream(context.Background(), account.ID, &TaskSummarizeRequest{
		ConversationID: conv.ID,
	}, func(chunk llm.StreamChunk) error {
		return nil
	})

	assert.Error(t, err)
}

func TestCaptainTaskService_RewriteStream_成功(t *testing.T) {
	_, mockProvider, svc := setupCaptainTaskService(t)

	mockProvider.streamChunks = []llm.StreamChunk{
		{Choices: []llm.StreamChoice{{Delta: llm.StreamDelta{Content: "感谢您的"}, FinishReason: ""}}},
		{Choices: []llm.StreamChoice{{Delta: llm.StreamDelta{Content: "来信"}, FinishReason: "stop"}}},
	}

	var collected []string
	err := svc.RewriteStream(context.Background(), 1, &TaskRewriteRequest{
		Content:  "来信收到了",
		Tone:     "professional",
		Language: "zh-CN",
	}, func(chunk llm.StreamChunk) error {
		if len(chunk.Choices) > 0 && chunk.Choices[0].Delta.Content != "" {
			collected = append(collected, chunk.Choices[0].Delta.Content)
		}
		return nil
	})

	require.NoError(t, err)
	assert.Len(t, collected, 2)
	assert.Equal(t, "感谢您的", collected[0])
}

func TestCaptainTaskService_RewriteStream_默认参数(t *testing.T) {
	_, mockProvider, svc := setupCaptainTaskService(t)

	mockProvider.streamChunks = []llm.StreamChunk{
		{Choices: []llm.StreamChoice{{Delta: llm.StreamDelta{Content: "重写文本"}, FinishReason: "stop"}}},
	}

	err := svc.RewriteStream(context.Background(), 1, &TaskRewriteRequest{
		Content: "原始内容",
	}, func(chunk llm.StreamChunk) error {
		return nil
	})

	require.NoError(t, err)
	require.NotNil(t, mockProvider.lastStreamReq)
	// 默认 tone 为 professional, language 为 zh-CN
	assert.Contains(t, mockProvider.lastStreamReq.Messages[0].Content, "zh-CN")
}

func TestCaptainTaskService_RewriteStream_LLM流错误(t *testing.T) {
	_, mockProvider, svc := setupCaptainTaskService(t)

	mockProvider.streamError = fmt.Errorf("LLM stream 不可用")

	err := svc.RewriteStream(context.Background(), 1, &TaskRewriteRequest{
		Content: "test",
	}, func(chunk llm.StreamChunk) error {
		return nil
	})

	assert.Error(t, err)
}

func TestCaptainTaskService_ReplySuggestionStream_回调中断(t *testing.T) {
	db, mockProvider, svc := setupCaptainTaskService(t)
	account := createTestAccount(t, db)
	assistant := createTestAssistant(t, db, account.ID, "助手")
	conv := createTestConversationWithMessages(t, db, account.ID, []struct{ sender, content string }{
		{"contact", "hello"},
	})

	mockProvider.embeddingResponse = makeEmbeddingResponse()
	mockProvider.streamChunks = []llm.StreamChunk{
		{Choices: []llm.StreamChoice{{Delta: llm.StreamDelta{Content: "chunk1"}, FinishReason: ""}}},
		{Choices: []llm.StreamChoice{{Delta: llm.StreamDelta{Content: "chunk2"}, FinishReason: ""}}},
		{Choices: []llm.StreamChoice{{Delta: llm.StreamDelta{Content: "chunk3"}, FinishReason: "stop"}}},
	}

	callCount := 0
	err := svc.ReplySuggestionStream(context.Background(), account.ID, &TaskReplySuggestionRequest{
		AssistantID:    assistant.ID,
		ConversationID: conv.ID,
	}, func(chunk llm.StreamChunk) error {
		callCount++
		if callCount == 2 {
			return fmt.Errorf("callback interrupted")
		}
		return nil
	})

	assert.Error(t, err)
	assert.Contains(t, err.Error(), "callback interrupted")
	assert.Equal(t, 2, callCount)
}