package config

import (
	"fmt"
	"os"
	"path/filepath"

	"gopkg.in/yaml.v3"
)

// ChunkConfig stores configuration for chunked translation
type ChunkConfig struct {
	Enabled bool   `yaml:"enabled"`
	Size    int    `yaml:"size"`
	Prompt  string `yaml:"prompt"`
	Context int    `yaml:"context"`
}

// Config stores the application configuration
type Config struct {
	APIBase      string      `yaml:"api_base"`
	APIKey       string      `yaml:"api_key"`
	Model        string      `yaml:"model"`
	SystemPrompt string      `yaml:"system_prompt"`
	// Concurrency related settings
	Concurrency  int         `yaml:"concurrency"`
	// Chunk related settings
	Chunk        ChunkConfig `yaml:"chunk"`
}

// Default system prompt as a placeholder
const DefaultSystemPrompt = "Placeholder"
const DefaultChunkPrompt = "Please continue translation"

// LoadConfig loads configuration from ~/.config/d10n.yaml
func LoadConfig() (*Config, error) {
	// Get user's home directory
	homeDir, err := os.UserHomeDir()
	if err != nil {
		return nil, fmt.Errorf("could not get home directory: %w", err)
	}

	// Default config path
	configPath := filepath.Join(homeDir, ".config", "d10n.yaml")

	// Check if config file exists
	if _, err := os.Stat(configPath); os.IsNotExist(err) {
		return &Config{
			SystemPrompt: DefaultSystemPrompt,
			Concurrency:  3,                   // Default concurrency
			Chunk: ChunkConfig{
				Enabled: false,               // Chunking disabled by default
				Size:    10240,               // Default chunk size in tokens
				Prompt:  DefaultChunkPrompt,  // Default chunk prompt
				Context: 2,                   // Default context size
			},
		}, nil
	}

	// Read config file
	data, err := os.ReadFile(configPath)
	if err != nil {
		return nil, fmt.Errorf("could not read config file: %w", err)
	}

	// Parse config
	var config Config
	if err := yaml.Unmarshal(data, &config); err != nil {
		return nil, fmt.Errorf("could not parse config file: %w", err)
	}

	// Set default values if not specified
	if config.SystemPrompt == "" {
		config.SystemPrompt = DefaultSystemPrompt
	}
	
	// Set default for concurrency
	if config.Concurrency <= 0 {
		config.Concurrency = 3
	}
	
	// Set defaults for chunk settings
	if config.Chunk.Size <= 0 {
		config.Chunk.Size = 10240
	}
	
	if config.Chunk.Prompt == "" {
		config.Chunk.Prompt = DefaultChunkPrompt
	}
	
	if config.Chunk.Context <= 0 {
		config.Chunk.Context = 2
	}

	return &config, nil
}