// Package config reads all settings from environment variables.
// Names and defaults match the table in the README.
package config

import (
	"fmt"
	"log"
	"net/url"
	"os"
	"path/filepath"
	"strconv"
)

type Config struct {
	Port                  int
	SSHPort               int
	DataDir               string
	OwnerDisplayName      string
	BaseURL               string
	PublicHTTPS           bool
	PublicOrigin          string
	RegistrationType      string // enabled | disabled | queue
	RegisterQuestion      string
	MaxUploadBytes        int64
	MaxUserUploadBytes    int64
	InlineMaxBytes        int64
	MaxRenderBytes        int64
	MaxRawDownloadBytes   int64
	SSHDisabled           bool
	SSHHostKeyPath        string
	ScannedRepoPrivate    bool
	TrustedProxy          bool
	RateLimitDisabled     bool
	CommitterName         string
	CommitterEmail        string
	ExtraAllowedSigners   string
	MaxTitleBytes         int
	MaxTextBodyBytes      int
	MaxUsernameBytes      int
	MaxPasswordBytes      int
	CIDockerSocket        string
	CIMaxHistory          int
	CIDefaultTimeout      int
	CIMaxConcurrent       int
	CIMaxArtifactBytes    int64
	MaxConcurrentArchives int
}

// intEnv returns def when unset or unparsable. min clamps the result;
// pass it where 0 would break the feature instead of disabling it.
func intEnv(key string, def, min int64) int64 {
	v := os.Getenv(key)
	if v == "" {
		return def
	}
	n, err := strconv.ParseInt(v, 10, 64)
	if err != nil {
		log.Printf("config: %s=%q is not a number, using %d", key, v, def)
		return def
	}
	if n < min {
		return min
	}
	return n
}

func strEnv(key, def string) string {
	if v := os.Getenv(key); v != "" {
		return v
	}
	return def
}

// boolEnv treats anything but "", "0" and "false" as true. A value that looks
// like neither is almost always a typo, so it is logged.
func boolEnv(key string) bool {
	v := os.Getenv(key)
	switch v {
	case "", "0", "false", "1", "true":
	default:
		log.Printf("config: %s=%q is not a boolean, reading it as true", key, v)
	}
	return v != "" && v != "0" && v != "false"
}

func Load() (*Config, error) {
	port := int(intEnv("PORT", 3000, 1))
	owner := strEnv("OWNER_DISPLAY_NAME", "Admin")
	dataDir, err := filepath.Abs(strEnv("DATA_DIR", "./data"))
	if err != nil {
		return nil, err
	}
	c := &Config{
		Port:                  port,
		SSHPort:               int(intEnv("SSH_PORT", 2222, 1)),
		DataDir:               dataDir,
		OwnerDisplayName:      owner,
		BaseURL:               strEnv("BASE_URL", fmt.Sprintf("http://localhost:%d", port)),
		RegistrationType:      strEnv("REGISTRATION_TYPE", "enabled"),
		RegisterQuestion:      os.Getenv("REGISTER_QUESTION"),
		MaxUploadBytes:        intEnv("MAX_UPLOAD_BYTES", 10<<20, 0),
		MaxUserUploadBytes:    intEnv("MAX_USER_UPLOAD_BYTES", 2<<20, 0),
		InlineMaxBytes:        intEnv("INLINE_MAX_BYTES", 512<<10, 0),
		MaxRenderBytes:        intEnv("MAX_RENDER_BYTES", 10<<20, 0),
		MaxRawDownloadBytes:   intEnv("MAX_RAW_DOWNLOAD_BYTES", 0, 0),
		SSHDisabled:           boolEnv("SSH_DISABLED"),
		SSHHostKeyPath:        strEnv("SSH_HOST_KEY_PATH", filepath.Join(dataDir, "ssh_host_key")),
		ScannedRepoPrivate:    os.Getenv("SCANNED_REPO_PRIVATE") != "0" && os.Getenv("SCANNED_REPO_PRIVATE") != "false",
		TrustedProxy:          boolEnv("TRUSTED_PROXY"),
		RateLimitDisabled:     boolEnv("RATE_LIMIT_DISABLED"),
		CommitterName:         strEnv("COMMITTER_NAME", owner),
		ExtraAllowedSigners:   os.Getenv("EXTRA_ALLOWED_SIGNERS_PATH"),
		MaxTitleBytes:         int(intEnv("MAX_TITLE_BYTES", 500, 0)),
		MaxTextBodyBytes:      int(intEnv("MAX_TEXT_BODY_BYTES", 100_000, 0)),
		MaxUsernameBytes:      int(intEnv("MAX_USERNAME_BYTES", 64, 0)),
		MaxPasswordBytes:      int(intEnv("MAX_PASSWORD_BYTES", 1024, 0)),
		CIDockerSocket:        os.Getenv("CI_DOCKER_SOCKET"),
		CIMaxHistory:          int(intEnv("CI_MAX_HISTORY", 50, 1)),
		CIDefaultTimeout:      int(intEnv("CI_DEFAULT_TIMEOUT", 3600, 1)),
		CIMaxConcurrent:       int(intEnv("CI_MAX_CONCURRENT", 2, 1)),
		CIMaxArtifactBytes:    intEnv("CI_MAX_ARTIFACT_BYTES", 512<<20, 1),
		MaxConcurrentArchives: int(intEnv("MAX_CONCURRENT_ARCHIVE_JOBS", 2, 1)),
	}
	switch c.RegistrationType {
	case "enabled", "disabled", "queue":
	default:
		return nil, fmt.Errorf("REGISTRATION_TYPE %q must be enabled, disabled or queue", c.RegistrationType)
	}
	u, err := url.Parse(c.BaseURL)
	if err != nil || u.Host == "" {
		return nil, fmt.Errorf("BASE_URL %q is not a valid URL", c.BaseURL)
	}
	c.PublicHTTPS = u.Scheme == "https"
	c.PublicOrigin = u.Scheme + "://" + u.Host
	c.CommitterEmail = strEnv("COMMITTER_EMAIL", owner+"@"+u.Hostname())
	return c, nil
}

// Derived paths under DataDir.
func (c *Config) DBPath() string             { return filepath.Join(c.DataDir, "hearthforge.db") }
func (c *Config) ReposDir() string           { return filepath.Join(c.DataDir, "repos") }
func (c *Config) AvatarsDir() string         { return filepath.Join(c.DataDir, "avatars") }
func (c *Config) ReleasesDir() string        { return filepath.Join(c.DataDir, "releases") }
func (c *Config) AllowedSignersPath() string { return filepath.Join(c.DataDir, "allowed_signers") }
func (c *Config) CIArtifactsDir() string     { return filepath.Join(c.DataDir, "ci", "artifacts") }