// Package config loads GitManager's runtime configuration from the environment
// (and an optional .env file). See AGENT.md §1.5 — every setting is env-driven;
// nothing is hardcoded.
package config

import (
	"os"
	"strconv"
	"strings"
	"time"

	"github.com/joho/godotenv"
)

// Config is the typed application configuration.
type Config struct {
	ListenAddr string // address the plain HTTP server binds to

	// TLS: when HTTPSAddr and both cert/key files are set, an HTTPS listener is
	// started in addition to the HTTP one. Claude Desktop's MCP connector only
	// accepts https:// URLs, so /mcp must be reachable over TLS (AGENT.md §8.1).
	HTTPSAddr   string // address the HTTPS server binds to ("" disables TLS)
	TLSCertFile string // PEM cert (e.g. an mkcert leaf trusted by the OS store)
	TLSKeyFile  string // PEM private key

	RepoRoots []string // roots to scan for git repositories
	GitBin    string   // path to the git binary

	ScanInterval     time.Duration // scanner refresh interval
	ScanMaxDepth     int           // max discovery depth under each root
	ScanIgnore       []string      // directory names to skip during discovery
	ScanFetchEnabled bool          // allow the scanner to run `git fetch`

	Dev     bool   // readable console logging vs structured JSON
	LogFile string // optional file to also append logs to

	GiteaURL    string // Gitea/Forgejo base URL (e.g. https://git.nilles.net)
	GiteaToken  string // Gitea token (read + PR write + branch delete) — §8.4
	GitHubToken string // optional forge token (later provider)
	GitLabToken string // optional forge token (later provider)
}

// Load reads .env (if present) then the environment, applying defaults.
// A missing .env is not an error — the environment may be set another way.
func Load() (Config, error) {
	_ = godotenv.Load()

	c := Config{
		ListenAddr:       env("LISTEN_ADDR", "127.0.0.1:8080"),
		HTTPSAddr:        env("HTTPS_ADDR", ""),
		TLSCertFile:      env("TLS_CERT_FILE", ""),
		TLSKeyFile:       env("TLS_KEY_FILE", ""),
		RepoRoots:        splitList(env("GIT_REPO_ROOTS", "")),
		GitBin:           env("GIT_BIN", "git"),
		ScanMaxDepth:     envInt("SCAN_MAX_DEPTH", 4),
		ScanIgnore:       splitList(env("SCAN_IGNORE", "node_modules,vendor,.cache")),
		ScanFetchEnabled: envBool("SCAN_FETCH_ENABLED", false),
		Dev:              strings.EqualFold(env("APP_ENV", "dev"), "dev"),
		LogFile:          env("LOG_FILE", ""),
		GiteaURL:         env("GITEA_URL", ""),
		GiteaToken:       env("GITEA_TOKEN", ""),
		GitHubToken:      env("GITHUB_TOKEN", ""),
		GitLabToken:      env("GITLAB_TOKEN", ""),
	}

	interval, err := time.ParseDuration(env("SCAN_INTERVAL", "30s"))
	if err != nil {
		return Config{}, err
	}
	c.ScanInterval = interval

	return c, nil
}

func env(key, def string) string {
	if v, ok := os.LookupEnv(key); ok && v != "" {
		return v
	}
	return def
}

func envInt(key string, def int) int {
	if v, ok := os.LookupEnv(key); ok {
		if n, err := strconv.Atoi(strings.TrimSpace(v)); err == nil {
			return n
		}
	}
	return def
}

func envBool(key string, def bool) bool {
	if v, ok := os.LookupEnv(key); ok {
		if b, err := strconv.ParseBool(strings.TrimSpace(v)); err == nil {
			return b
		}
	}
	return def
}

// splitList splits a comma-separated value, trimming spaces and dropping empties.
func splitList(v string) []string {
	var out []string
	for _, part := range strings.Split(v, ",") {
		if p := strings.TrimSpace(part); p != "" {
			out = append(out, p)
		}
	}
	return out
}