package main

import (
	"bufio"
	"context"
	"fmt"
	"os"
	"strings"
)

const systemPrompt = `You are a coding assistant running inside a CLI. You have file tools scoped
to the current project directory. All paths are relative to the project root; absolute paths
and paths that escape the root (via "..") will be rejected. Prefer listing and reading before
editing. Keep replies concise.`

func main() {
	root, err := os.Getwd()
	if err != nil {
		fmt.Fprintln(os.Stderr, "error getting working directory:", err)
		os.Exit(1)
	}

	if err := loadConfig(root); err != nil {
		fmt.Fprintln(os.Stderr, "config error:", err)
		os.Exit(1)
	}

	apiKey := os.Getenv("OPENAI_API_KEY")
	baseURL := getEnvDefault("OPENAI_BASE_URL", "https://api.openai.com/v1")
	model := getEnvDefault("OPENAI_MODEL", "gpt-4o-mini")

	if apiKey == "" {
		fmt.Fprintln(os.Stderr, "OPENAI_API_KEY is not set")
		os.Exit(1)
	}

	client := NewClient(baseURL, apiKey, model)
	tools := toolDefinitions()

	messages := []Message{{Role: "system", Content: systemPrompt}}

	fmt.Printf("NyxTex agent — model=%s  root=%s\n", model, root)
	fmt.Println("Type your request. Empty line to submit. Ctrl+D or /exit to quit.")

	reader := bufio.NewReader(os.Stdin)
	for {
		fmt.Print("\n> ")
		input, err := readUserInput(reader)
		if err != nil {
			fmt.Println()
			return
		}
		input = strings.TrimSpace(input)
		if input == "" {
			continue
		}
		if input == "/exit" || input == "/quit" {
			return
		}

		messages = append(messages, Message{Role: "user", Content: input})

		if err := runTurn(context.Background(), client, tools, root, &messages); err != nil {
			fmt.Fprintln(os.Stderr, "error:", err)
		}
	}
}

func readUserInput(r *bufio.Reader) (string, error) {
	line, err := r.ReadString('\n')
	if err != nil && line == "" {
		return "", err
	}
	return line, nil
}

// runTurn sends the conversation and handles any tool-call loop until the
// assistant produces a plain text reply.
func runTurn(ctx context.Context, client *Client, tools []Tool, root string, messages *[]Message) error {
	for {
		msg, err := client.Chat(ctx, *messages, tools)
		if err != nil {
			return err
		}
		*messages = append(*messages, msg)

		if len(msg.ToolCalls) == 0 {
			if strings.TrimSpace(msg.Content) != "" {
				fmt.Println(msg.Content)
			}
			return nil
		}

		for _, tc := range msg.ToolCalls {
			fmt.Printf("  [tool] %s %s\n", tc.Function.Name, tc.Function.Arguments)
			result := runTool(root, tc.Function.Name, tc.Function.Arguments)
			*messages = append(*messages, Message{
				Role:       "tool",
				ToolCallID: tc.ID,
				Name:       tc.Function.Name,
				Content:    result,
			})
		}
	}
}

func getEnvDefault(key, def string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return def
}