// Package config loads pansy's runtime configuration from the environment.
//
// Every value has a sensible default so `pansy` runs with zero configuration
// for local use; production deployments override via PANSY_* env vars. Auth
// values (local + OIDC) are plumbed here now and consumed by the auth issues
// (#4 local, #5 OIDC).
package config

import (
	"log/slog"
	"os"
	"strconv"
	"strings"
)

// Registration gates local self-service signup.
const (
	RegistrationOpen   = "open"
	RegistrationClosed = "closed"
)

// DefaultAgentModel is the assistant's model when PANSY_AGENT_MODEL is unset.
const DefaultAgentModel = "ollama-cloud/glm-5.2:cloud"

// Config is the fully-resolved runtime configuration.
type Config struct {
	// Port is the TCP port the HTTP server listens on (PANSY_PORT, default 8080).
	Port int
	// DBPath is the SQLite database file path (PANSY_DB, default ./pansy.db).
	DBPath string
	// BaseURL is the externally-visible base URL, used to derive the OIDC
	// redirect URI and absolute links (PANSY_BASE_URL). Empty in bare local dev.
	BaseURL string
	// Registration is "open" or "closed"; gates POST /auth/register for local
	// accounts (PANSY_REGISTRATION, default open). OIDC JIT provisioning ignores
	// this — the IdP gates access.
	Registration string
	// LocalAuth enables argon2id username/password auth (PANSY_LOCAL_AUTH,
	// default true). Set false for pure-Authentik deployments.
	LocalAuth bool
	// OIDC holds the optional OpenID Connect provider settings.
	OIDC OIDCConfig
	// Agent holds the garden-assistant settings.
	Agent AgentConfig
	// TrustedProxies is the set of proxy CIDRs/IPs gin trusts for client IP
	// resolution (PANSY_TRUSTED_PROXIES, comma-separated). Empty trusts none.
	TrustedProxies []string
}

// OIDCConfig holds the OpenID Connect provider settings (Authentik is the
// primary IdP). Consumed by #5.
type OIDCConfig struct {
	Issuer       string // PANSY_OIDC_ISSUER — discovery base URL
	ClientID     string // PANSY_OIDC_CLIENT_ID
	ClientSecret string // PANSY_OIDC_CLIENT_SECRET
	ButtonLabel  string // PANSY_OIDC_BUTTON_LABEL — login-page button text
}

// AgentConfig holds the garden assistant's settings.
type AgentConfig struct {
	// Model is the majordomo model spec, passed VERBATIM to majordomo.Parse
	// (PANSY_AGENT_MODEL). The grammar is majordomo's, not pansy's — parsing or
	// validating it here would only mean two places to update when it grows. A
	// comma-separated spec is a failover chain, so
	// "ollama-cloud/glm-5.2:cloud,ollama-cloud/kimi-k2.6:cloud" gets a fallback
	// for free.
	Model string
	// OllamaCloudAPIKey authenticates against Ollama Cloud
	// (OLLAMA_CLOUD_API_KEY — the same secret name gadfly uses, which is why
	// it isn't majordomo's own OLLAMA_API_KEY; pansy passes it explicitly rather
	// than relying on ambient environment).
	OllamaCloudAPIKey string
	// Enabled turns the assistant on (PANSY_AGENT_ENABLED). Defaults to on when
	// a key is present, so an instance with no key starts cleanly and simply
	// doesn't offer the agent — the same shape as OIDC 404ing when unconfigured.
	Enabled bool
	// VisionModel is the model that reads a photographed seed packet
	// (PANSY_VISION_MODEL). Empty by default: the seed-packet capture feature is
	// only offered when a vision-capable model is configured (in env or Settings)
	// and a key is present. Passed verbatim to majordomo.Parse, like Model.
	VisionModel string
}

// Enabled reports whether enough OIDC config is present to attempt discovery.
func (o OIDCConfig) Enabled() bool {
	return o.Issuer != "" && o.ClientID != ""
}

// OIDCReady reports whether OIDC login can actually be offered: it needs an
// issuer + client ID and a BaseURL to build the absolute redirect URI that
// providers require. Both the login page (via /auth/providers) and route
// registration gate on this, so the advertised methods match the live routes.
func (c *Config) OIDCReady() bool {
	return c.OIDC.Enabled() && c.BaseURL != ""
}

// RegistrationOpen reports whether local self-service signup is allowed.
func (c *Config) RegistrationOpen() bool {
	return c.Registration == RegistrationOpen
}

// Load reads configuration from the environment, applying defaults. It never
// fails: invalid numeric/boolean values fall back to the default and are logged.
func Load() *Config {
	cfg := &Config{
		Port:         envInt("PANSY_PORT", 8080),
		DBPath:       envStr("PANSY_DB", "./pansy.db"),
		BaseURL:      strings.TrimRight(envStr("PANSY_BASE_URL", ""), "/"),
		Registration: envStr("PANSY_REGISTRATION", RegistrationOpen),
		LocalAuth:    envBool("PANSY_LOCAL_AUTH", true),
		OIDC: OIDCConfig{
			Issuer:       envStr("PANSY_OIDC_ISSUER", ""),
			ClientID:     envStr("PANSY_OIDC_CLIENT_ID", ""),
			ClientSecret: envStr("PANSY_OIDC_CLIENT_SECRET", ""),
			ButtonLabel:  envStr("PANSY_OIDC_BUTTON_LABEL", "Sign in with Authentik"),
		},
		TrustedProxies: envList("PANSY_TRUSTED_PROXIES"),
	}

	agentKey := envStr("OLLAMA_CLOUD_API_KEY", "")
	cfg.Agent = AgentConfig{
		Model:             envStr("PANSY_AGENT_MODEL", DefaultAgentModel),
		OllamaCloudAPIKey: agentKey,
		// Default on when a key is present: having configured the key IS the
		// opt-in, and making people set a second flag to use what they just
		// configured is a papercut with no upside.
		Enabled: envBool("PANSY_AGENT_ENABLED", agentKey != ""),
		// No default vision model: unlike chat there's no obvious safe default,
		// and the feature stays off until an admin names one that can see.
		VisionModel: envStr("PANSY_VISION_MODEL", ""),
	}

	if cfg.Registration != RegistrationOpen && cfg.Registration != RegistrationClosed {
		slog.Warn("config: invalid PANSY_REGISTRATION, defaulting to open", "value", cfg.Registration)
		cfg.Registration = RegistrationOpen
	}

	if cfg.Port < 1 || cfg.Port > 65535 {
		slog.Warn("config: PANSY_PORT out of range, using default", "value", cfg.Port, "default", 8080)
		cfg.Port = 8080
	}

	return cfg
}

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

func envInt(key string, def int) int {
	v, ok := os.LookupEnv(key)
	if !ok || v == "" {
		return def
	}
	n, err := strconv.Atoi(v)
	if err != nil {
		slog.Warn("config: invalid int env, using default", "key", key, "value", v, "default", def)
		return def
	}
	return n
}

func envBool(key string, def bool) bool {
	v, ok := os.LookupEnv(key)
	if !ok || v == "" {
		return def
	}
	b, err := strconv.ParseBool(v)
	if err != nil {
		slog.Warn("config: invalid bool env, using default", "key", key, "value", v, "default", def)
		return def
	}
	return b
}

func envList(key string) []string {
	v, ok := os.LookupEnv(key)
	if !ok || v == "" {
		return nil
	}
	parts := strings.Split(v, ",")
	out := make([]string, 0, len(parts))
	for _, p := range parts {
		if p = strings.TrimSpace(p); p != "" {
			out = append(out, p)
		}
	}
	return out
}