//go:build linux || freebsd
// +build linux freebsd

package config

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

	"codeberg.org/petrbalvin/goget/internal/auth"
	"codeberg.org/petrbalvin/goget/internal/core"
	"codeberg.org/petrbalvin/interpres"
)

// AuthConfig holds authentication configuration
type AuthConfig struct {
	Username     string           `json:"username,omitempty" toml:"username,omitempty"`
	Password     string           `json:"password,omitempty" toml:"password,omitempty"`
	PasswordFile string           `json:"password_file,omitempty" toml:"password_file,omitempty"`
	AuthType     string           `json:"auth_type,omitempty" toml:"auth_type,omitempty"` // basic, digest, auto
	OAuth        auth.OAuthConfig `json:"oauth,omitempty" toml:"oauth,omitempty"`
}

// RecursiveConfig holds recursive download configuration
type RecursiveConfig struct {
	Enabled         bool     `json:"enabled,omitempty" toml:"enabled,omitempty"`
	MaxDepth        int      `json:"max_depth,omitempty" toml:"max_depth,omitempty"`
	FollowExternal  bool     `json:"follow_external,omitempty" toml:"follow_external,omitempty"`
	ExcludePatterns []string `json:"exclude_patterns,omitempty" toml:"exclude_patterns,omitempty"`
	IncludePatterns []string `json:"include_patterns,omitempty" toml:"include_patterns,omitempty"`
	Delay           string   `json:"delay,omitempty" toml:"delay,omitempty"`
	Parallel        int      `json:"parallel,omitempty" toml:"parallel,omitempty"`
}

// ExtractConfig holds archive extraction configuration
type ExtractConfig struct {
	Enabled             bool     `json:"enabled,omitempty" toml:"enabled,omitempty"`
	OutputDir           string   `json:"output_dir,omitempty" toml:"output_dir,omitempty"`
	StripComponents     int      `json:"strip_components,omitempty" toml:"strip_components,omitempty"`
	ExcludePatterns     []string `json:"exclude_patterns,omitempty" toml:"exclude_patterns,omitempty"`
	PreservePermissions bool     `json:"preserve_permissions,omitempty" toml:"preserve_permissions,omitempty"`
	AutoDetect          bool     `json:"auto_detect,omitempty" toml:"auto_detect,omitempty"`
}

// Config represents the application configuration
type Config struct {
	Timeout            time.Duration   `json:"timeout,omitempty" toml:"timeout,omitempty"`
	Parallel           int             `json:"parallel,omitempty" toml:"parallel,omitempty"`
	OutputDir          string          `json:"output_dir,omitempty" toml:"output_dir,omitempty"`
	Verbose            bool            `json:"verbose,omitempty" toml:"verbose,omitempty"`
	Debug              bool            `json:"debug,omitempty" toml:"debug,omitempty"`
	IPv4Fallback       bool            `json:"ipv4_fallback,omitempty" toml:"ipv4_fallback,omitempty"`
	Proxy              string          `json:"proxy,omitempty" toml:"proxy,omitempty"`
	UserAgent          string          `json:"user_agent,omitempty" toml:"user_agent,omitempty"`
	AutoDecompress     bool            `json:"auto_decompress,omitempty" toml:"auto_decompress,omitempty"`
	InsecureSkipVerify bool            `json:"insecure_skip_verify,omitempty" toml:"insecure_skip_verify,omitempty"`
	ChecksumAlgo       string          `json:"checksum_algo,omitempty" toml:"checksum_algo,omitempty"`
	Auth               AuthConfig      `json:"auth,omitempty" toml:"auth,omitempty"`
	MaxSpeed           int64           `json:"max_speed,omitempty" toml:"max_speed,omitempty"`
	AutoResume         bool            `json:"auto_resume,omitempty" toml:"auto_resume,omitempty"`
	KeepMetadata       bool            `json:"keep_metadata,omitempty" toml:"keep_metadata,omitempty"`
	Color              string          `json:"color,omitempty" toml:"color,omitempty"`
	ProgressStyle      string          `json:"progress_style,omitempty" toml:"progress_style,omitempty"`
	ShowETA            bool            `json:"show_eta,omitempty" toml:"show_eta,omitempty"`
	Recursive          RecursiveConfig `json:"recursive,omitempty" toml:"recursive,omitempty"`
	Extract            ExtractConfig   `json:"extract,omitempty" toml:"extract,omitempty"`
	CookieJar          string          `json:"cookie_jar,omitempty" toml:"cookie_jar,omitempty"`
	DNSServers         []string        `json:"dns_servers,omitempty" toml:"dns_servers,omitempty"`
	MaxRetries         int             `json:"max_retries,omitempty" toml:"max_retries,omitempty"`
	configPath         string
}

// DefaultConfig returns the default configuration
func DefaultConfig() *Config {
	return &Config{
		Timeout:            30 * time.Minute,
		Parallel:           0,
		OutputDir:          ".",
		Verbose:            true,
		Debug:              false,
		IPv4Fallback:       true,
		Proxy:              "",
		UserAgent:          core.Name + "/" + core.Version,
		AutoDecompress:     true,
		InsecureSkipVerify: false,
		ChecksumAlgo:       "sha256",
		Auth:               AuthConfig{},
		MaxSpeed:           0,
		AutoResume:         true,
		KeepMetadata:       false,
		Color:              "auto",
		ProgressStyle:      "unicode",
		ShowETA:            true,
		Recursive: RecursiveConfig{
			Enabled:         false,
			MaxDepth:        3,
			FollowExternal:  false,
			ExcludePatterns: []string{},
			IncludePatterns: []string{},
			Delay:           "100ms",
		},
		Extract: ExtractConfig{
			Enabled:             false,
			OutputDir:           "",
			StripComponents:     0,
			ExcludePatterns:     []string{},
			PreservePermissions: true,
			AutoDetect:          true,
		},
		CookieJar: "",
	}
}

// Load loads the configuration from file
func Load(customPath string) (*Config, error) {
	cfg := DefaultConfig()
	configPath := customPath
	if configPath == "" {
		configPath = getConfigPath()
	}
	if configPath == "" {
		return cfg, nil
	}
	cfg.configPath = configPath
	data, err := os.ReadFile(configPath)
	if err != nil {
		if os.IsNotExist(err) {
			return cfg, nil
		}
		return nil, fmt.Errorf("failed to read config: %w", err)
	}
	if err := interpres.Unmarshal(data, cfg); err != nil {
		return nil, fmt.Errorf("failed to parse config %s: %w", configPath, err)
	}
	if cfg.Auth.PasswordFile != "" && cfg.Auth.Password == "" {
		passwordPath := expandTilde(cfg.Auth.PasswordFile)
		if data, err := os.ReadFile(passwordPath); err == nil {
			cfg.Auth.Password = strings.TrimSpace(string(data))
		}
	}
	return cfg, nil
}

// Save writes the configuration to disk
func (c *Config) Save() error {
	if c.configPath == "" {
		c.configPath = getConfigPath()
		if c.configPath == "" {
			return fmt.Errorf("cannot determine config path")
		}
	}
	if err := os.MkdirAll(filepath.Dir(c.configPath), 0755); err != nil {
		return err
	}
	cfgCopy := *c
	cfgCopy.Auth.Password = ""
	cfgCopy.Auth.OAuth.ClientSecret = ""
	cfgCopy.Auth.OAuth.AccessToken = ""
	cfgCopy.Auth.OAuth.RefreshToken = ""
	data, err := interpres.Marshal(cfgCopy)
	if err != nil {
		return err
	}
	return os.WriteFile(c.configPath, data, 0600)
}

// Path returns the config file path
func (c *Config) Path() string {
	return c.configPath
}

// CLIFlags holds CLI overrides to merge into the configuration.
type CLIFlags struct {
	Timeout         time.Duration
	Parallel        int
	Verbose         bool
	Debug           bool
	MaxSpeed        int64
	Proxy           string
	NoIPv4          bool
	NoDecompress    bool
	Username        string
	Password        string
	CookieJar       string
	Recursive       bool
	MaxDepth        int
	FollowExternal  bool
	ExcludePatterns []string
	Extract         bool
	ExtractDir      string
	StripComponents int
}

// Merge merges CLI overrides into the configuration.
func (c *Config) Merge(cli *CLIFlags) {
	if cli.Timeout > 0 {
		c.Timeout = cli.Timeout
	}
	if cli.Parallel >= 0 {
		c.Parallel = cli.Parallel
	}
	if cli.Verbose {
		c.Verbose = true
	}
	if cli.Debug {
		c.Debug = true
	}
	if cli.MaxSpeed >= 0 {
		c.MaxSpeed = cli.MaxSpeed
	}
	if cli.Proxy != "" {
		c.Proxy = cli.Proxy
	}
	if cli.NoIPv4 {
		c.IPv4Fallback = false
	}
	if cli.NoDecompress {
		c.AutoDecompress = false
	}
	if cli.Username != "" {
		c.Auth.Username = cli.Username
		c.Auth.Password = cli.Password
	}
	if cli.CookieJar != "" {
		c.CookieJar = cli.CookieJar
	}
	if cli.Recursive {
		c.Recursive.Enabled = true
	}
	if cli.MaxDepth > 0 {
		c.Recursive.MaxDepth = cli.MaxDepth
	}
	if cli.FollowExternal {
		c.Recursive.FollowExternal = true
	}
	if len(cli.ExcludePatterns) > 0 {
		c.Recursive.ExcludePatterns = cli.ExcludePatterns
	}
	if cli.Extract {
		c.Extract.Enabled = true
	}
	if cli.ExtractDir != "" {
		c.Extract.OutputDir = cli.ExtractDir
	}
	if cli.StripComponents >= 0 {
		c.Extract.StripComponents = cli.StripComponents
	}
}

func getConfigPath() string {
	if path := os.Getenv("GOGET_CONFIG"); path != "" {
		return path
	}
	if xdg := os.Getenv("XDG_CONFIG_HOME"); xdg != "" {
		return filepath.Join(xdg, "goget", "config.toml")
	}
	if home, err := os.UserHomeDir(); err == nil {
		return filepath.Join(home, ".config", "goget", "config.toml")
	}
	return ""
}

func expandTilde(path string) string {
	if strings.HasPrefix(path, "~/") {
		if home, err := os.UserHomeDir(); err == nil {
			return filepath.Join(home, path[2:])
		}
	}
	return path
}

func (c *Config) GetEffectiveTimeout(fileSize int64, userOverride time.Duration) time.Duration {
	tc := core.DefaultTimeoutConfig()
	return tc.CalculateTimeout(fileSize, userOverride)
}

func (c *Config) GetParallelConnections(fileSize int64) int {
	if c.Parallel > 0 {
		return c.Parallel
	}
	if fileSize >= 100*1024*1024 {
		return 4
	}
	return 1
}

func (c *Config) ShouldUseColors() bool {
	switch c.Color {
	case "always":
		return true
	case "never":
		return false
	default:
		if os.Getenv("NO_COLOR") != "" {
			return false
		}
		return true
	}
}

func (c *Config) IsExcluded(url string) bool {
	for _, pattern := range c.Recursive.ExcludePatterns {
		if strings.Contains(url, pattern) {
			return true
		}
	}
	return false
}

func (c *Config) GetRecursiveDelay() time.Duration {
	if c.Recursive.Delay == "" {
		return 100 * time.Millisecond
	}
	d, err := time.ParseDuration(c.Recursive.Delay)
	if err != nil {
		return 100 * time.Millisecond
	}
	return d
}

func (c *Config) GetExtractOutputDir(defaultDir string) string {
	if c.Extract.OutputDir != "" {
		return c.Extract.OutputDir
	}
	return defaultDir
}

func ParseSpeed(s string) int64 {
	if s == "" || s == "0" {
		return 0
	}
	s = strings.TrimSpace(strings.ToLower(s))
	var multiplier int64 = 1
	switch {
	case strings.HasSuffix(s, "tb/s"):
		multiplier = 1000 * 1000 * 1000 * 1000
		s = strings.TrimSuffix(s, "tb/s")
	case strings.HasSuffix(s, "gb/s"):
		multiplier = 1000 * 1000 * 1000
		s = strings.TrimSuffix(s, "gb/s")
	case strings.HasSuffix(s, "mb/s"):
		multiplier = 1000 * 1000
		s = strings.TrimSuffix(s, "mb/s")
	case strings.HasSuffix(s, "kb/s"):
		multiplier = 1000
		s = strings.TrimSuffix(s, "kb/s")
	case strings.HasSuffix(s, "/s"):
		s = strings.TrimSuffix(s, "/s")
	}
	var value float64
	fmt.Sscanf(s, "%f", &value)
	return int64(value * float64(multiplier))
}