package engine

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

	"github.com/spf13/viper"
)

type Config struct {
	DefaultFilter  string `mapstructure:"default_filter"`
	DefaultSort    string `mapstructure:"default_sort"`
	ColorOutput    bool   `mapstructure:"color_output"`
	WeekStartDay   string `mapstructure:"week_start_day"`
	DefaultDueTime string `mapstructure:"default_due_time"`

	// Sync settings
	SyncEnabled      bool   `mapstructure:"sync_enabled"`
	SyncURL          string `mapstructure:"sync_url"`
	SyncAPIKey       string `mapstructure:"sync_api_key"`
	SyncClientID     string `mapstructure:"sync_client_id"`
	SyncStrategy     string `mapstructure:"sync_strategy"`
	SyncQueueOffline bool   `mapstructure:"sync_queue_offline"`
}

var globalConfig *Config

// GetConfigDir returns the configuration directory path
func GetConfigDir() (string, error) {
	home, err := os.UserHomeDir()
	if err != nil {
		return "", fmt.Errorf("failed to get home directory: %w", err)
	}
	return filepath.Join(home, ".config", "jade"), nil
}

// GetDBPath returns the path to the SQLite database
func GetDBPath() (string, error) {
	configDir, err := GetConfigDir()
	if err != nil {
		return "", err
	}
	return filepath.Join(configDir, "opal.db"), nil
}

// GetConfigPath returns the path to the config file
func GetConfigPath() (string, error) {
	configDir, err := GetConfigDir()
	if err != nil {
		return "", err
	}
	return filepath.Join(configDir, "opal.yml"), nil
}

// LoadConfig loads the configuration from file or creates default
func LoadConfig() (*Config, error) {
	if globalConfig != nil {
		return globalConfig, nil
	}

	configDir, err := GetConfigDir()
	if err != nil {
		return nil, err
	}

	// Ensure config directory exists
	if err := os.MkdirAll(configDir, 0755); err != nil {
		return nil, fmt.Errorf("failed to create config directory: %w", err)
	}

	configPath, err := GetConfigPath()
	if err != nil {
		return nil, err
	}

	v := viper.New()
	v.SetConfigFile(configPath)
	v.SetConfigType("yaml")

	// Set defaults
	v.SetDefault("default_filter", "status:pending")
	v.SetDefault("default_sort", "due,priority")
	v.SetDefault("color_output", true)
	v.SetDefault("week_start_day", "monday")
	v.SetDefault("default_due_time", "")

	// Sync defaults
	v.SetDefault("sync_enabled", false)
	v.SetDefault("sync_url", "")
	v.SetDefault("sync_api_key", "")
	v.SetDefault("sync_client_id", "")
	v.SetDefault("sync_strategy", "last-write-wins")
	v.SetDefault("sync_queue_offline", true)

	// Try to read existing config
	err = v.ReadInConfig()
	if err != nil {
		// Config doesn't exist, create it with defaults
		// Write config with defaults (ignoring the error type check for now)
		if err := v.WriteConfigAs(configPath); err != nil {
			return nil, fmt.Errorf("failed to create config file: %w", err)
		}
		// Try reading again
		if err := v.ReadInConfig(); err != nil {
			return nil, fmt.Errorf("failed to read newly created config: %w", err)
		}
	}

	cfg := &Config{}
	if err := v.Unmarshal(cfg); err != nil {
		return nil, fmt.Errorf("failed to unmarshal config: %w", err)
	}

	globalConfig = cfg
	return cfg, nil
}

// SaveConfig saves the configuration to file
func SaveConfig(cfg *Config) error {
	configPath, err := GetConfigPath()
	if err != nil {
		return err
	}

	v := viper.New()
	v.SetConfigFile(configPath)
	v.SetConfigType("yaml")

	v.Set("default_filter", cfg.DefaultFilter)
	v.Set("default_sort", cfg.DefaultSort)
	v.Set("color_output", cfg.ColorOutput)
	v.Set("week_start_day", cfg.WeekStartDay)
	v.Set("default_due_time", cfg.DefaultDueTime)

	// Sync settings
	v.Set("sync_enabled", cfg.SyncEnabled)
	v.Set("sync_url", cfg.SyncURL)
	v.Set("sync_api_key", cfg.SyncAPIKey)
	v.Set("sync_client_id", cfg.SyncClientID)
	v.Set("sync_strategy", cfg.SyncStrategy)
	v.Set("sync_queue_offline", cfg.SyncQueueOffline)

	return v.WriteConfig()
}

// GetConfig returns the loaded config or loads it if not already loaded
func GetConfig() (*Config, error) {
	if globalConfig != nil {
		return globalConfig, nil
	}
	return LoadConfig()
}

// GetWeekStart returns the configured week start day
func (c *Config) GetWeekStart() time.Weekday {
	if strings.ToLower(c.WeekStartDay) == "sunday" {
		return time.Sunday
	}
	return time.Monday // default
}

// GetDefaultDueTime returns the configured default due time (HH:MM format or empty)
func (c *Config) GetDefaultDueTime() string {
	return c.DefaultDueTime
}