package config

import "errors"
import "fmt"
import "os"
import "path/filepath"
import "strconv"
import "strings"
import "time"
import "unicode"

import yaml "github.com/goccy/go-yaml"

type Config struct {
	App              AppConfig     `yaml:"app"`
	CTL              CTLConfig     `yaml:"ctl"`
	PublicBaseURL    string        `yaml:"public-base-url"`
	DataDir          string        `yaml:"data-dir"`
	FrontendDir      string        `yaml:"frontend-dir"`
	DBDriver         string        `yaml:"db-driver"`
	DBDSN            string        `yaml:"db-dsn"`
	SessionTTL       Duration      `yaml:"session-ttl"`
	AuthMode         string        `yaml:"auth-mode"`
	LDAPURL          string        `yaml:"ldap-url"`
	LDAPBindDN       string        `yaml:"ldap-bind-dn"`
	LDAPBindPassword string        `yaml:"ldap-bind-password"`
	LDAPUserBaseDN   string        `yaml:"ldap-user-base-dn"`
	LDAPUserFilter   string        `yaml:"ldap-user-filter"`
	LDAPTLSInsecureSkipVerify bool `yaml:"ldap-tls-insecure-skip-verify"`
	OIDCClientID     string        `yaml:"oidc-client-id"`
	OIDCClientSecret string        `yaml:"oidc-client-secret"`
	OIDCAuthorizeURL string        `yaml:"oidc-authorize-url"`
	OIDCTokenURL     string        `yaml:"oidc-token-url"`
	OIDCUserInfoURL  string        `yaml:"oidc-userinfo-url"`
	OIDCRedirectURL  string        `yaml:"oidc-redirect-url"`
	OIDCScopes       string        `yaml:"oidc-scopes"`
	OIDCEnabled      bool          `yaml:"oidc-enabled"`
	OIDCTLSInsecureSkipVerify bool `yaml:"oidc-tls-insecure-skip-verify"`
	DockerHTTPPrefix string        `yaml:"docker-http-prefix"`
	GitHTTPPrefix    string        `yaml:"git-http-prefix"`
	RPMHTTPPrefix    string        `yaml:"rpm-http-prefix"`
}

type CTLConfig struct {
	Service CTLServiceConfig `yaml:"service"`
	TLS     CTLTLSConfig     `yaml:"tls"`
}

type CTLServiceConfig struct {
	Addrs []string `yaml:"addresses"`
}

type CTLTLSConfig struct {
	Enabled             bool   `yaml:"enabled"`
	ServerCertSource    string `yaml:"server-cert-source"`
	CertFile            string `yaml:"cert-file"`
	KeyFile             string `yaml:"key-file"`
	PKIServerCertID     string `yaml:"pki-server-cert-id"`
	ClientAuth          string `yaml:"client-auth"`
	ClientCAFile        string `yaml:"client-ca-file"`
	PKIClientCAID       string `yaml:"pki-client-ca-id"`
	MinVersion          string `yaml:"min-version"`
}

type AppConfig struct {
	LogMask    []string `yaml:"log-mask"`
	LogFile    string   `yaml:"log-file"`
	LogMaxSize int64    `yaml:"log-max-size"`
	LogRotate  int      `yaml:"log-rotate"`
	SiteName   string   `yaml:"site-name"`
}

const DefaultEnvPrefix string = "CODIT_"

type Duration time.Duration

func Load(path string) (Config, error) {
	return LoadWithEnvPrefix(path, DefaultEnvPrefix)
}

func LoadWithEnvPrefix(path string, envPrefix string) (Config, error) {
	return LoadFilesWithEnvPrefix([]string{path}, envPrefix)
}

func LoadFiles(paths []string) (Config, error) {
	return LoadFilesWithEnvPrefix(paths, DefaultEnvPrefix)
}

func LoadFilesWithEnvPrefix(paths []string, envPrefix string) (Config, error) {
	var cfg Config
	var serverID string
	var dataDir string
	var err error
	serverID = ServerIdFromEnvPrefix(envPrefix)
	dataDir = "./" + serverID + "-data"
	cfg = Config{
		App: AppConfig{LogMask: []string{}},
		CTL: CTLConfig{
			//Service: CTLServiceConfig{Addrs: []string{":1080"}},
			TLS: CTLTLSConfig{ServerCertSource: "files", ClientAuth: "none", MinVersion: "1.2"},
		},
		DataDir:        dataDir,
		FrontendDir:    filepath.Join("..", "frontend", "dist"),
		DBDriver:       "sqlite",
		DBDSN:          "file:" + dataDir + "/" + serverID + ".db",
		SessionTTL:     Duration(24 * time.Hour),
		AuthMode:       "db",
		LDAPUserFilter: "(uid={username})",
		OIDCScopes:     "openid profile email",
		DockerHTTPPrefix: "/v2",
		GitHTTPPrefix:  "/git",
		RPMHTTPPrefix:  "/rpm",
	}
	err = loadConfigFiles(&cfg, paths)
	if err != nil {
		return cfg, err
	}
	override(&cfg, envPrefix)
	normalizeCTLConfig(&cfg)
	cfg.AuthMode = strings.ToLower(strings.TrimSpace(cfg.AuthMode))
	cfg.DockerHTTPPrefix = NormalizeHTTPPrefix(cfg.DockerHTTPPrefix, "/v2")
	cfg.GitHTTPPrefix = NormalizeHTTPPrefix(cfg.GitHTTPPrefix, "/git")
	cfg.RPMHTTPPrefix = NormalizeHTTPPrefix(cfg.RPMHTTPPrefix, "/rpm")
	if cfg.DBDSN == "" {
		return cfg, errors.New("db dsn is required")
	}
	return cfg, nil
}

func normalizeCTLConfig(cfg *Config) {
	cfg.CTL.Service.Addrs = NormalizeHTTPAddrs(cfg.CTL.Service.Addrs)
	cfg.CTL.TLS.ServerCertSource = strings.ToLower(strings.TrimSpace(cfg.CTL.TLS.ServerCertSource))
	cfg.CTL.TLS.CertFile = strings.TrimSpace(cfg.CTL.TLS.CertFile)
	cfg.CTL.TLS.KeyFile = strings.TrimSpace(cfg.CTL.TLS.KeyFile)
	cfg.CTL.TLS.PKIServerCertID = strings.TrimSpace(cfg.CTL.TLS.PKIServerCertID)
	cfg.CTL.TLS.ClientAuth = strings.ToLower(strings.TrimSpace(cfg.CTL.TLS.ClientAuth))
	cfg.CTL.TLS.ClientCAFile = strings.TrimSpace(cfg.CTL.TLS.ClientCAFile)
	cfg.CTL.TLS.PKIClientCAID = strings.TrimSpace(cfg.CTL.TLS.PKIClientCAID)
	cfg.CTL.TLS.MinVersion = strings.TrimSpace(cfg.CTL.TLS.MinVersion)
}

func loadConfigFiles(cfg *Config, paths []string) error {
	var expanded []string
	var path string
	var i int
	var err error

	expanded, err = expandConfigFiles(paths)
	if err != nil {
		return err
	}
	for i = 0; i < len(expanded); i++ {
		path = expanded[i]
		err = loadConfigFile(cfg, path)
		if err != nil {
			return fmt.Errorf("load config file %s - %w", path, err)
		}
	}
	return nil
}

func loadConfigFile(cfg *Config, path string) error {
	var f *os.File
	var yd *yaml.Decoder
	var err error

	if strings.TrimSpace(path) == "" {
		return nil
	}
	f, err = os.Open(path)
	if err != nil {
		return err
	}
	yd = yaml.NewDecoder(f, yaml.AllowDuplicateMapKey(), yaml.DisallowUnknownField())
	err = yd.Decode(cfg)
	f.Close()
	return err
}

func expandConfigFiles(paths []string) ([]string, error) {
	var out []string
	var matches []string
	var path string
	var i int
	var j int
	var err error

	for i = 0; i < len(paths); i++ {
		path = strings.TrimSpace(paths[i])
		if path == "" {
			continue
		}
		if hasGlobMeta(path) {
			matches, err = filepath.Glob(path)
			if err != nil {
				return nil, err
			}
			for j = 0; j < len(matches); j++ {
				out = append(out, matches[j])
			}
		} else {
			out = append(out, path)
		}
	}
	return out, nil
}

func hasGlobMeta(path string) bool {
	return strings.ContainsAny(path, "*?[")
}

func override(cfg *Config, envPrefix string) {
	var v string

	v = getEnv(envPrefix, "LOG_MASK")
	if v != "" { cfg.App.LogMask = splitCSV(v) }
	v = getEnv(envPrefix, "LOG_FILE")
	if v != "" { cfg.App.LogFile = v }
	v = getEnv(envPrefix, "LOG_MAX_SIZE")
	if v != "" { cfg.App.LogMaxSize, _ = strconv.ParseInt(v, 10, 64) }
	v = getEnv(envPrefix, "LOG_ROTATE")
	if v != "" { cfg.App.LogRotate, _ = strconv.Atoi(v) }
	v = getEnv(envPrefix, "SITE_NAME")
	if v != "" { cfg.App.SiteName = v }

	v = getEnv(envPrefix, "CTL_SERVICE_ADDRESSES")
	if v != "" { cfg.CTL.Service.Addrs = splitCSV(v) }
	v = getEnv(envPrefix, "CTL_TLS_ENABLED")
	if v != "" { cfg.CTL.TLS.Enabled = parseEnvBool(v) }
	v = getEnv(envPrefix, "CTL_TLS_SERVER_CERT_SOURCE")
	if v != "" { cfg.CTL.TLS.ServerCertSource = v }
	v = getEnv(envPrefix, "CTL_TLS_CERT_FILE")
	if v != "" { cfg.CTL.TLS.CertFile = v }
	v = getEnv(envPrefix, "CTL_TLS_KEY_FILE")
	if v != "" { cfg.CTL.TLS.KeyFile = v }
	v = getEnv(envPrefix, "CTL_TLS_PKI_SERVER_CERT_ID")
	if v != "" { cfg.CTL.TLS.PKIServerCertID = v }
	v = getEnv(envPrefix, "CTL_TLS_CLIENT_AUTH")
	if v != "" { cfg.CTL.TLS.ClientAuth = v }
	v = getEnv(envPrefix, "CTL_TLS_CLIENT_CA_FILE")
	if v != "" { cfg.CTL.TLS.ClientCAFile = v }
	v = getEnv(envPrefix, "CTL_TLS_PKI_CLIENT_CA_ID")
	if v != "" { cfg.CTL.TLS.PKIClientCAID = v }
	v = getEnv(envPrefix, "CTL_TLS_MIN_VERSION")
	if v != "" { cfg.CTL.TLS.MinVersion = v }

	v = getEnv(envPrefix, "PUBLIC_BASE_URL")
	if v != "" { cfg.PublicBaseURL = v }
	v = getEnv(envPrefix, "DATA_DIR")
	if v != "" { cfg.DataDir = v }
	v = getEnv(envPrefix, "FRONTEND_DIR")
	if v != "" { cfg.FrontendDir = v }
	v = getEnv(envPrefix, "DB_DRIVER")
	if v != "" { cfg.DBDriver = v }
	v = getEnv(envPrefix, "DB_DSN")
	if v != "" { cfg.DBDSN = v }
	v = getEnv(envPrefix, "AUTH_MODE")
	if v != "" { cfg.AuthMode = v }
	v = getEnv(envPrefix, "LDAP_URL")
	if v != "" { cfg.LDAPURL = v }
	v = getEnv(envPrefix, "LDAP_BIND_DN")
	if v != "" { cfg.LDAPBindDN = v }
	v = getEnv(envPrefix, "LDAP_BIND_PASSWORD")
	if v != "" { cfg.LDAPBindPassword = v }
	v = getEnv(envPrefix, "LDAP_USER_BASE_DN")
	if v != "" { cfg.LDAPUserBaseDN = v }
	v = getEnv(envPrefix, "LDAP_USER_FILTER")
	if v != "" { cfg.LDAPUserFilter = v }
	v = getEnv(envPrefix, "LDAP_TLS_INSECURE_SKIP_VERIFY")
	if v != "" { cfg.LDAPTLSInsecureSkipVerify = parseEnvBool(v) }

	v = getEnv(envPrefix, "OIDC_CLIENT_ID")
	if v != "" { cfg.OIDCClientID = v }
	v = getEnv(envPrefix, "OIDC_CLIENT_SECRET")
	if v != "" { cfg.OIDCClientSecret = v }
	v = getEnv(envPrefix, "OIDC_AUTHORIZE_URL")
	if v != "" { cfg.OIDCAuthorizeURL = v }
	v = getEnv(envPrefix, "OIDC_TOKEN_URL")
	if v != "" { cfg.OIDCTokenURL = v }
	v = getEnv(envPrefix, "OIDC_USERINFO_URL")
	if v != "" { cfg.OIDCUserInfoURL = v }
	v = getEnv(envPrefix, "OIDC_REDIRECT_URL")
	if v != "" { cfg.OIDCRedirectURL = v }
	v = getEnv(envPrefix, "OIDC_SCOPES")
	if v != "" { cfg.OIDCScopes = v }
	v = getEnv(envPrefix, "OIDC_ENABLED")
	if v != "" { cfg.OIDCEnabled = parseEnvBool(v) }
	v = getEnv(envPrefix, "OIDC_TLS_INSECURE_SKIP_VERIFY")
	if v != "" { cfg.OIDCTLSInsecureSkipVerify = parseEnvBool(v) }

	v = getEnv(envPrefix, "DOCKER_HTTP_PREFIX")
	if v != "" { cfg.DockerHTTPPrefix = v }
	v = getEnv(envPrefix, "GIT_HTTP_PREFIX")
	if v != "" { cfg.GitHTTPPrefix = v }
	v = getEnv(envPrefix, "RPM_HTTP_PREFIX")
	if v != "" { cfg.RPMHTTPPrefix = v }
}

func getEnv(prefix string, name string) string {
	if prefix == "" { return os.Getenv(name) }
	return os.Getenv(prefix + name)
}


func (d Duration) Duration() time.Duration {
	return time.Duration(d)
}

func (d *Duration) UnmarshalYAML(b []byte) error {
	var raw string
	var asNumber int64
	var err error
	var parsed time.Duration

	raw = strings.TrimSpace(string(b))
	raw = strings.Trim(raw, "'\"")
	parsed, err = time.ParseDuration(raw)
	if err == nil {
		*d = Duration(parsed)
		return nil
	}
	asNumber, err = strconv.ParseInt(raw, 10, 64)
	if err == nil {
		*d = Duration(time.Duration(asNumber))
		return nil
	}
	return errors.New("invalid duration format")
}

func parseEnvBool(v string) bool {
	var lowered string
	var parsed bool
	var err error
	lowered = strings.ToLower(strings.TrimSpace(v))
	if lowered == "true" || lowered == "yes" || lowered == "y" || lowered == "on" {
		return true
	}
	if lowered == "false" || lowered == "no" || lowered == "n" || lowered == "off" {
		return false
	}
	parsed, err = strconv.ParseBool(lowered)
	if err == nil {
		return parsed
	}
	return false
}

func splitCSV(v string) []string {
	var parts []string
	var out []string
	var i int
	var p string
	parts = strings.Split(v, ",")
	for i = 0; i < len(parts); i++ {
		p = strings.TrimSpace(parts[i])
		if p == "" {
			continue
		}
		out = append(out, p)
	}
	return out
}

func NormalizeHTTPAddrs(values []string) []string {
	var out []string
	var i int
	var v string
	for i = 0; i < len(values); i++ {
		v = strings.TrimSpace(values[i])
		if v == "" {
			continue
		}
		out = append(out, v)
	}
	return out
}

func NormalizeHTTPPrefix(value string, fallback string) string {
	value = strings.TrimSpace(value)
	if value == "" {
		value = fallback
	}
	if !strings.HasPrefix(value, "/") {
		value = "/" + value
	}
	value = strings.TrimRight(value, "/")
	if value == "" {
		return "/"
	}
	return value
}

func NormalizeServerId(value string) string {
	value = strings.ToLower(strings.TrimSpace(value))
	value = strings.ReplaceAll(value, "_", "-")
	value = strings.Trim(value, "-")
	if value == "" {
		return "codit"
	}
	return value
}

func EnvPrefixFromServerId(value string) string {
	var prefix string
	prefix = strings.ToUpper(strings.ReplaceAll(NormalizeServerId(value), "-", "_"))
	if !strings.HasSuffix(prefix, "_") {
		prefix = prefix + "_"
	}
	return prefix
}

func TitleFromServerId(value string) string {
	var id string
	var parts []string
	var i int

	id = NormalizeServerId(value)
	parts = strings.Split(id, "-")
	for i = 0; i < len(parts); i++ {
		parts[i] = titleWord(parts[i])
	}
	return strings.Join(parts, " ")
}

func ServerIdFromEnvPrefix(envPrefix string) string {
	var value string
	value = strings.TrimSpace(envPrefix)
	value = strings.TrimSuffix(value, "_")
	return NormalizeServerId(value)
}

func titleWord(value string) string {
	var runes []rune
	var i int

	runes = []rune(strings.ToLower(strings.TrimSpace(value)))
	if len(runes) == 0 {
		return ""
	}
	runes[0] = unicode.ToTitle(runes[0])
	for i = 1; i < len(runes); i++ {
		runes[i] = unicode.ToLower(runes[i])
	}
	return string(runes)
}