//
//  Copyright 2026 The InfiniFlow Authors. All Rights Reserved.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//

package models

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"ragflow/internal/common"
	"strings"
)

// PPIOModel implements ModelDriver for PPIO.
//
// PPIO exposes OpenAI-compatible chat completions and model listing endpoints.
type PPIOModel struct {
	baseModel BaseModel
}

func NewPPIOModel(baseURL map[string]string, urlSuffix URLSuffix) *PPIOModel {
	return &PPIOModel{
		baseModel: BaseModel{
			BaseURL:    baseURL,
			URLSuffix:  urlSuffix,
			httpClient: NewDriverHTTPClient(),
		},
	}
}

func (p *PPIOModel) NewInstance(baseURL map[string]string) ModelDriver {
	return NewPPIOModel(baseURL, p.baseModel.URLSuffix)
}

func (p *PPIOModel) Name() string {
	return "ppio"
}

type PPIOChatResponse struct {
	ID      string `json:"id"`
	Choices []struct {
		FinishReason string `json:"finish_reason"`
		Index        int    `json:"index"`
		Message      struct {
			Content          string `json:"content"`
			ReasoningContent string `json:"reasoning_content"`
			Role             string `json:"role"`
		} `json:"message"`
	} `json:"choices"`
	Created int        `json:"created"`
	Model   string     `json:"model"`
	Object  string     `json:"object"`
	Usage   TokenUsage `json:"usage"`
}

func (p *PPIOModel) endpoint(apiConfig *APIConfig, suffix string) (string, error) {
	baseURL, err := p.baseModel.GetBaseURL(apiConfig)
	if err != nil {
		return "", err
	}
	baseURL = strings.TrimSuffix(baseURL, "/")
	return fmt.Sprintf("%s/%s", baseURL, strings.TrimPrefix(suffix, "/")), nil
}

type ppioChatMessage struct {
	Content          string `json:"content"`
	ReasoningContent string `json:"reasoning_content"`
}

type ppioChatChoice struct {
	Message      ppioChatMessage `json:"message"`
	Delta        ppioChatMessage `json:"delta"`
	FinishReason string          `json:"finish_reason"`
}

type ppioChatResponse struct {
	ID      string           `json:"id"`
	Choices []ppioChatChoice `json:"choices"`
	Error   interface{}      `json:"error"`
	Usage   struct {
		CompletionTokens int `json:"completion_tokens"`
		PromptTokens     int `json:"prompt_tokens"`
		TotalTokens      int `json:"total_tokens"`
	} `json:"usage"`
	FinishReason string `json:"finish_reason"`
}

func (p *PPIOModel) ChatWithMessages(ctx context.Context, modelName string, messages []Message, apiConfig *APIConfig, chatModelConfig *ChatConfig, modelUsage *common.ModelUsage) (*ChatResponse, error) {
	if err := p.baseModel.APIConfigCheck(apiConfig); err != nil {
		return nil, err
	}
	if strings.TrimSpace(modelName) == "" {
		return nil, fmt.Errorf("model name is required")
	}
	if len(messages) == 0 {
		return nil, fmt.Errorf("messages is empty")
	}

	url, err := p.endpoint(apiConfig, p.baseModel.URLSuffix.Chat)
	if err != nil {
		return nil, err
	}

	jsonData, err := json.Marshal(buildRequestBody(chatModelConfig, modelName, messages, false))
	if err != nil {
		return nil, fmt.Errorf("failed to marshal request: %w", err)
	}

	ctx, cancel := context.WithTimeout(ctx, nonStreamCallTimeout)
	defer cancel()

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewBuffer(jsonData))
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", *apiConfig.ApiKey))

	resp, err := p.baseModel.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to send request: %w", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("failed to read response: %w", err)
	}
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("API request failed with status %d: %s", resp.StatusCode, string(body))
	}

	return parseChatCompletionResponse(body, chatModelConfig, modelUsage, func(body []byte, chatConfig *ChatConfig) (chatResponseParts, error) {
		var result PPIOChatResponse
		if err := json.Unmarshal(body, &result); err != nil {
			return chatResponseParts{}, fmt.Errorf("failed to parse response: %w", err)
		}
		if len(result.Choices) == 0 {
			var errResp struct {
				Error interface{} `json:"error"`
			}
			if err := json.Unmarshal(body, &errResp); err == nil && errResp.Error != nil {
				return chatResponseParts{}, fmt.Errorf("ppio: upstream error: %v", errResp.Error)
			}
			return chatResponseParts{}, fmt.Errorf("no choices in response")
		}

		choice := &result.Choices[0]
		content := choice.Message.Content
		reasonContent := choice.Message.ReasoningContent

		return chatResponseParts{
			RequestID:     result.ID,
			Content:       &content,
			ReasonContent: &reasonContent,
			Usage:         &result.Usage,
		}, nil
	})
}

func (p *PPIOModel) ChatStreamlyWithSender(ctx context.Context, modelName string, messages []Message, apiConfig *APIConfig, chatModelConfig *ChatConfig, modelUsage *common.ModelUsage, sender func(*string, *string) error) error {
	if err := p.baseModel.APIConfigCheck(apiConfig); err != nil {
		return err
	}

	if sender == nil {
		return fmt.Errorf("sender is required")
	}
	if strings.TrimSpace(modelName) == "" {
		return fmt.Errorf("model name is required")
	}
	if len(messages) == 0 {
		return fmt.Errorf("messages is empty")
	}
	if chatModelConfig != nil && chatModelConfig.Stream != nil && !*chatModelConfig.Stream {
		return fmt.Errorf("stream must be true in ChatStreamlyWithSender")
	}

	url, err := p.endpoint(apiConfig, p.baseModel.URLSuffix.Chat)
	if err != nil {
		return err
	}

	reqBody := buildRequestBody(chatModelConfig, modelName, messages, true)
	reqBody["stream_options"] = map[string]interface{}{"include_usage": true}

	jsonData, err := json.Marshal(reqBody)
	if err != nil {
		return fmt.Errorf("failed to marshal request: %w", err)
	}

	ctx, cancel := context.WithTimeout(ctx, streamCallTimeout)
	defer cancel()

	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewBuffer(jsonData))
	if err != nil {
		return fmt.Errorf("failed to create request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", *apiConfig.ApiKey))
	req.Header.Set("Accept", "text/event-stream")

	resp, err := p.baseModel.httpClient.Do(req)
	if err != nil {
		return fmt.Errorf("failed to send request: %w", err)
	}
	defer resp.Body.Close()

	if resp.StatusCode != http.StatusOK {
		body, _ := io.ReadAll(resp.Body)
		return fmt.Errorf("API request failed with status %d: %s", resp.StatusCode, string(body))
	}

	sawTerminal := false
	done, err := ParseSSEStream[ppioChatResponse](resp.Body, func(event ppioChatResponse) error {
		if event.Error != nil {
			return fmt.Errorf("ppio: upstream stream error: %v", event.Error)
		}
		if event.Usage.TotalTokens > 0 || event.Usage.PromptTokens > 0 || event.Usage.CompletionTokens > 0 {
			applyStreamUsage(chatModelConfig, modelUsage, &TokenUsage{
				PromptTokens:     event.Usage.PromptTokens,
				CompletionTokens: event.Usage.CompletionTokens,
				TotalTokens:      event.Usage.TotalTokens,
			})
		}
		if len(event.Choices) == 0 {
			return nil
		}

		choice := event.Choices[0]
		reasoning := choice.Delta.ReasoningContent
		if reasoning != "" {
			if err := sender(nil, &reasoning); err != nil {
				return err
			}
		}
		if choice.Delta.Content != "" {
			if err := sender(&choice.Delta.Content, nil); err != nil {
				return err
			}
		}
		if choice.FinishReason != "" || event.FinishReason != "" {
			sawTerminal = true
		}
		return nil
	})
	if err != nil {
		return fmt.Errorf("failed to scan response body: %w", err)
	}
	if !done && !sawTerminal {
		return fmt.Errorf("ppio: stream ended before [DONE] or finish_reason")
	}

	endOfStream := "[DONE]"
	return sender(&endOfStream, nil)
}

type ppioModelInfo struct {
	ID string `json:"id"`
}

type ppioListModelsResponse struct {
	Data  []ModelListItem `json:"data"`
	Error interface{}     `json:"error"`
}

func (p *PPIOModel) ListModels(ctx context.Context, apiConfig *APIConfig) ([]ListModelResponse, error) {
	if err := p.baseModel.APIConfigCheck(apiConfig); err != nil {
		return nil, err
	}

	url, err := p.endpoint(apiConfig, p.baseModel.URLSuffix.Models)
	if err != nil {
		return nil, err
	}

	ctx, cancel := context.WithTimeout(ctx, nonStreamCallTimeout)
	defer cancel()

	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", *apiConfig.ApiKey))

	resp, err := p.baseModel.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to send request: %w", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("failed to read response: %w", err)
	}
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("API request failed with status %d: %s", resp.StatusCode, string(body))
	}

	var result ppioListModelsResponse
	if err = json.Unmarshal(body, &result); err != nil {
		return nil, fmt.Errorf("failed to parse response: %w", err)
	}
	if result.Error != nil {
		return nil, fmt.Errorf("ppio: upstream error: %v", result.Error)
	}

	return ParseListModel(ModelList{Models: result.Data}), nil
}

func (p *PPIOModel) CheckConnection(ctx context.Context, apiConfig *APIConfig) error {
	_, err := p.ListModels(ctx, apiConfig)
	return err
}

type PPIOEmbeddingData struct {
	EmbeddingData
	Object string `json:"object"`
}

type PPIOEmbeddingResponse struct {
	ID     string              `json:"id"`
	Object string              `json:"object"`
	Data   []PPIOEmbeddingData `json:"data"`
	Usage  struct {
		PromptTokens int `json:"prompt_tokens"`
		TotalTokens  int `json:"total_tokens"`
	} `json:"usage"`
}

func (p *PPIOModel) Embed(ctx context.Context, modelName *string, texts []string, apiConfig *APIConfig, embeddingConfig *EmbeddingConfig, modelUsage *common.ModelUsage) ([]EmbeddingData, error) {
	if err := p.baseModel.APIConfigCheck(apiConfig); err != nil {
		return nil, err
	}

	if len(texts) == 0 {
		return []EmbeddingData{}, nil
	}

	if modelName == nil || *modelName == "" {
		return nil, fmt.Errorf("model name is required")
	}

	baseURL, err := p.baseModel.GetBaseURL(apiConfig)
	if err != nil {
		return nil, err
	}
	baseURL = strings.TrimSuffix(baseURL, "/")
	url := fmt.Sprintf("%s/%s", baseURL, p.baseModel.URLSuffix.Embedding)

	reqBody := map[string]interface{}{
		"model":           *modelName,
		"input":           texts,
		"encoding_format": "float",
	}
	if embeddingConfig != nil && embeddingConfig.EncodingFormat != "" {
		reqBody["encoding_format"] = embeddingConfig.EncodingFormat
	}

	jsonData, err := json.Marshal(reqBody)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal request: %w", err)
	}

	ctx, cancel := context.WithTimeout(ctx, nonStreamCallTimeout)
	defer cancel()

	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewBuffer(jsonData))
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", *apiConfig.ApiKey))

	resp, err := p.baseModel.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to send request: %w", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("failed to read response: %w", err)
	}

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("PPIO embeddings API error: %s, body: %s", resp.Status, string(body))
	}

	var parsed PPIOEmbeddingResponse
	if err = json.Unmarshal(body, &parsed); err != nil {
		return nil, fmt.Errorf("failed to parse response: %w", err)
	}

	embeddings := make([]EmbeddingData, len(texts))
	filled := make([]bool, len(texts))
	for _, item := range parsed.Data {
		if item.Index < 0 || item.Index >= len(texts) {
			return nil, fmt.Errorf("ppio: response index %d out of range for %d inputs", item.Index, len(texts))
		}
		if filled[item.Index] {
			return nil, fmt.Errorf("ppio: duplicate embedding index %d in response", item.Index)
		}
		embeddings[item.Index] = EmbeddingData{
			Embedding: item.Embedding,
			Index:     item.Index,
		}
		filled[item.Index] = true
	}
	for i, ok := range filled {
		if !ok {
			return nil, fmt.Errorf("ppio: missing embedding for input index %d", i)
		}
	}
	recordResponseUsage(modelUsage, parsed.ID, &TokenUsage{
		PromptTokens: parsed.Usage.PromptTokens,
		TotalTokens:  parsed.Usage.TotalTokens,
	}, "embedding")

	return embeddings, nil
}

func (p *PPIOModel) Rerank(ctx context.Context, modelName *string, query string, documents []string, apiConfig *APIConfig, rerankConfig *RerankConfig, modelUsage *common.ModelUsage) (*RerankResponse, error) {
	if err := p.baseModel.APIConfigCheck(apiConfig); err != nil {
		return nil, err
	}

	if len(documents) == 0 {
		return &RerankResponse{}, nil
	}
	if modelName == nil || *modelName == "" {
		return nil, fmt.Errorf("model name is required")
	}

	resolvedBaseURL, err := p.baseModel.GetBaseURL(apiConfig)
	if err != nil {
		return nil, err
	}
	url := fmt.Sprintf("%s/%s", strings.TrimSuffix(resolvedBaseURL, "/"), p.baseModel.URLSuffix.Rerank)

	topN := len(documents)
	if rerankConfig != nil && rerankConfig.TopN > 0 {
		topN = rerankConfig.TopN
	}

	reqBody := map[string]any{
		"model":     *modelName,
		"query":     query,
		"documents": documents,
		"top_n":     topN,
	}

	jsonData, err := json.Marshal(reqBody)
	if err != nil {
		return nil, fmt.Errorf("failed to marshal request: %w", err)
	}

	ctx, cancel := context.WithTimeout(ctx, nonStreamCallTimeout)
	defer cancel()

	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewBuffer(jsonData))
	if err != nil {
		return nil, fmt.Errorf("failed to create request: %w", err)
	}

	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", fmt.Sprintf("Bearer %s", *apiConfig.ApiKey))

	resp, err := p.baseModel.httpClient.Do(req)
	if err != nil {
		return nil, fmt.Errorf("failed to send request: %w", err)
	}
	defer resp.Body.Close()

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return nil, fmt.Errorf("failed to read response: %w", err)
	}

	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("PPIO rerank API error: status %d, body: %s", resp.StatusCode, string(body))
	}

	var rerankResp struct {
		ID      string `json:"id"`
		Results []struct {
			Index          int     `json:"index"`
			RelevanceScore float64 `json:"relevance_score"`
		} `json:"results"`
		Usage struct {
			CompletionTokens int `json:"completion_tokens"`
			PromptTokens     int `json:"prompt_tokens"`
			TotalTokens      int `json:"total_tokens"`
		} `json:"usage"`
	}

	if err = json.Unmarshal(body, &rerankResp); err != nil {
		return nil, fmt.Errorf("failed to decode response: %w", err)
	}

	var rerankResponse RerankResponse
	for _, result := range rerankResp.Results {
		rerankResult := RerankResult{
			Index:          result.Index,
			RelevanceScore: result.RelevanceScore,
		}
		rerankResponse.Data = append(rerankResponse.Data, rerankResult)
	}
	recordResponseUsage(modelUsage, rerankResp.ID, &TokenUsage{
		PromptTokens:     rerankResp.Usage.PromptTokens,
		CompletionTokens: rerankResp.Usage.CompletionTokens,
		TotalTokens:      rerankResp.Usage.TotalTokens,
	}, "rerank")

	return &rerankResponse, nil
}

func (p *PPIOModel) Balance(ctx context.Context, apiConfig *APIConfig) (map[string]interface{}, error) {
	return nil, fmt.Errorf("%s, no such method", p.Name())
}

func (p *PPIOModel) TranscribeAudio(ctx context.Context, modelName *string, file *string, apiConfig *APIConfig, asrConfig *ASRConfig, modelUsage *common.ModelUsage) (*ASRResponse, error) {
	return nil, fmt.Errorf("%s, no such method", p.Name())
}

func (p *PPIOModel) TranscribeAudioWithSender(ctx context.Context, modelName *string, file *string, apiConfig *APIConfig, asrConfig *ASRConfig, modelUsage *common.ModelUsage, sender func(*string, *string) error) error {
	return fmt.Errorf("%s, no such method", p.Name())
}

func (p *PPIOModel) AudioSpeech(ctx context.Context, modelName *string, audioContent *string, apiConfig *APIConfig, ttsConfig *TTSConfig, modelUsage *common.ModelUsage) (*TTSResponse, error) {
	return nil, fmt.Errorf("%s, no such method", p.Name())
}

func (p *PPIOModel) AudioSpeechWithSender(ctx context.Context, modelName *string, audioContent *string, apiConfig *APIConfig, ttsConfig *TTSConfig, modelUsage *common.ModelUsage, sender func(*string, *string) error) error {
	return fmt.Errorf("%s, no such method", p.Name())
}

func (p *PPIOModel) OCRFile(ctx context.Context, modelName *string, content []byte, url *string, apiConfig *APIConfig, ocrConfig *OCRConfig, modelUsage *common.ModelUsage) (*OCRFileResponse, error) {
	return nil, fmt.Errorf("%s, no such method", p.Name())
}

func (p *PPIOModel) ParseFile(ctx context.Context, modelName *string, content []byte, url *string, apiConfig *APIConfig, parseFileConfig *ParseFileConfig, modelUsage *common.ModelUsage) (*ParseFileResponse, error) {
	return nil, fmt.Errorf("%s, no such method", p.Name())
}

func (p *PPIOModel) ListTasks(ctx context.Context, apiConfig *APIConfig) ([]ListTaskStatus, error) {
	return nil, fmt.Errorf("%s, no such method", p.Name())
}

func (p *PPIOModel) ShowTask(ctx context.Context, taskID string, apiConfig *APIConfig) (*TaskResponse, error) {
	return nil, fmt.Errorf("%s, no such method", p.Name())
}