package main

import (
	"bufio"
	"context"
	"errors"
	"flag"
	"fmt"
	"io"
	"log"
	"os"
	"strings"

	"github.com/cloudwego/eino-ext/components/model/openai"
	"github.com/cloudwego/eino/schema"
)

// sourceEnv a crude .env file reader
func sourceEnv() {
	file, err := os.Open(".env")
	if err != nil {
		fmt.Println(".env not found or cannot be read")
		return
	}
	defer file.Close()

	scanner := bufio.NewScanner(file)

	for scanner.Scan() {
		split_env := strings.Split(scanner.Text(), "=")
		if len(split_env) != 2 {
			log.Fatal(".env file expexted '=' to delimit key and value. Check .env file for proper format.")
		}
		fmt.Printf("Setting from .env: %s\n", split_env[0])
		os.Setenv(split_env[0], split_env[1])
	}
	if err := scanner.Err(); err != nil {
		log.Fatal(err)
	}

}

type AgentConfig struct {
	BaseUrl string
	ModelId string
	ApiKey  string
}

func NewAgentConfig() *AgentConfig {
	url, ok := os.LookupEnv("OPENAI_BASE_URL")
	if !ok {
		log.Fatal("An OPENAI_BASE_URL must be specified as an environment variable.")
	}

	modelId, ok := os.LookupEnv("OPENAI_API_MODEL")
	if !ok {
		log.Fatal("A model id must be specified with OPENAI_API_MODEL as an environment variable.")
	}

	apiKey, ok := os.LookupEnv("OPENAI_API_KEY")
	if !ok {
		fmt.Println("No API found as OPENAI_API_KEY. Using dummy value")
		apiKey = "dummyvalue"
	}
	return &AgentConfig{url, modelId, apiKey}
}

func main() {
	sourceEnv()
	var instruction string
	flag.StringVar(&instruction, "instruction", "You are a helpful assistant.", "Set a system prompt for your agent.")
	flag.Parse()

	query := strings.TrimSpace(strings.Join(flag.Args(), " "))
	if query == "" {
		fmt.Fprintln(os.Stderr, "usage: go run main -- \"your question\"")
		os.Exit(2)
	}

	ctx := context.Background()
	agentCfg := NewAgentConfig()
	cm, err := openai.NewChatModel(ctx, &openai.ChatModelConfig{
		Model:   agentCfg.ModelId,
		BaseURL: agentCfg.BaseUrl,
		APIKey:  agentCfg.ApiKey,
	})
	if err != nil {
		fmt.Fprintln(os.Stderr, err)
		os.Exit(1)
	}

	messages := []*schema.Message{
		schema.SystemMessage(instruction),
		schema.UserMessage(query),
	}

	fmt.Fprint(os.Stdout, "[assistant] ")
	stream, err := cm.Stream(ctx, messages)
	if err != nil {
		log.Fatal(err)
	}
	defer stream.Close()

	for {
		frame, err := stream.Recv()
		if errors.Is(err, io.EOF) {
			break
		}
		if err != nil {
			log.Fatal(err)
		}
		if frame != nil {
			fmt.Fprint(os.Stdout, frame.Content)
		}
	}
	fmt.Fprintln(os.Stdout)

}