package config

import (
	"fmt"
	"time"
)

// CacheConfig configures the cache behavior
type CacheConfig struct {
	// Enabled controls whether caching is active
	Enabled bool `yaml:"enabled" default:"true" help:"Enable response caching"`

	// DefaultTTL is the default time-to-live for cache entries
	DefaultTTL string `yaml:"default_ttl" default:"5m" help:"Default cache TTL (e.g., '5m', '1h')"`

	// SearchTTL is the TTL for search results
	SearchTTL string `yaml:"search_ttl" default:"2m" help:"Cache TTL for search results (e.g., '2m', '30s')"`

	// MetadataTTL is the TTL for metadata and corpus information
	MetadataTTL string `yaml:"metadata_ttl" default:"15m" help:"Cache TTL for metadata and corpus info (e.g., '15m', '1h')"`

	// MaxSize is the maximum number of cache entries
	MaxSize int `yaml:"max_size" default:"1000" help:"Maximum number of cache entries"`
}

// DefaultCacheConfig returns a default cache configuration
func DefaultCacheConfig() *CacheConfig {
	return &CacheConfig{
		Enabled:     true,
		DefaultTTL:  "5m",  // 5 minutes
		SearchTTL:   "2m",  // 2 minutes - search results change less frequently
		MetadataTTL: "15m", // 15 minutes - metadata is more stable
		MaxSize:     1000,
	}
}

// Validate validates cache configuration
func (c *CacheConfig) Validate() error {
	if !c.Enabled {
		return nil // Skip validation if cache is disabled
	}

	if c.MaxSize <= 0 {
		return fmt.Errorf("cache max_size must be positive, got %d", c.MaxSize)
	}

	// Validate TTL duration strings
	if _, err := time.ParseDuration(c.DefaultTTL); err != nil {
		return fmt.Errorf("invalid default_ttl '%s': %w", c.DefaultTTL, err)
	}

	if _, err := time.ParseDuration(c.SearchTTL); err != nil {
		return fmt.Errorf("invalid search_ttl '%s': %w", c.SearchTTL, err)
	}

	if _, err := time.ParseDuration(c.MetadataTTL); err != nil {
		return fmt.Errorf("invalid metadata_ttl '%s': %w", c.MetadataTTL, err)
	}

	return nil
}

// GetDefaultTTL returns the default TTL as a time.Duration
func (c *CacheConfig) GetDefaultTTL() time.Duration {
	if !c.Enabled {
		return 0
	}

	duration, err := time.ParseDuration(c.DefaultTTL)
	if err != nil {
		return 5 * time.Minute // fallback to default
	}
	return duration
}

// GetSearchTTL returns the search TTL as a time.Duration
func (c *CacheConfig) GetSearchTTL() time.Duration {
	if !c.Enabled {
		return 0
	}

	duration, err := time.ParseDuration(c.SearchTTL)
	if err != nil {
		return 2 * time.Minute // fallback to default
	}
	return duration
}

// GetMetadataTTL returns the metadata TTL as a time.Duration
func (c *CacheConfig) GetMetadataTTL() time.Duration {
	if !c.Enabled {
		return 0
	}

	duration, err := time.ParseDuration(c.MetadataTTL)
	if err != nil {
		return 15 * time.Minute // fallback to default
	}
	return duration
}