// Package config provides configuration management for Kandev.
// It supports loading configuration from environment variables, config files, and defaults.
package config

import (
	"fmt"
	"net"
	"net/url"
	"os"
	"path/filepath"
	"runtime"
	"strings"
	"time"

	"github.com/kandev/kandev/internal/common/ports"
	"github.com/kandev/kandev/internal/profiles"
	"github.com/spf13/viper"
)

// kandevHomeSubdir is the hidden directory name used for the Kandev root
// under the user's home directory (e.g. ~/.kandev). This is the single
// source of truth for the dotdir name; derived paths go through
// ResolvedHomeDir / ResolvedDataDir rather than re-constructing it.
const kandevHomeSubdir = ".kandev"

// Config holds all configuration sections for Kandev.
type Config struct {
	// HomeDir is the root Kandev directory (e.g. ~/.kandev in prod, or
	// <repo>/.kandev-dev during local development). When empty, falls back
	// to ~/.kandev. All workspace artifacts (data, tasks, worktrees, repos)
	// live under this root.
	HomeDir                string                       `mapstructure:"homeDir"`
	Server                 ServerConfig                 `mapstructure:"server"`
	Tasks                  TasksConfig                  `mapstructure:"tasks"`
	Credentials            CredentialsConfig            `mapstructure:"credentials"`
	Limits                 LimitsConfig                 `mapstructure:"limits"`
	MessageQueue           MessageQueueConfig           `mapstructure:"messageQueue"`
	Agentctl               AgentctlConfig               `mapstructure:"agentctl"`
	Planning               PlanningConfig               `mapstructure:"planning"`
	Observability          ObservabilityConfig          `mapstructure:"observability"`
	Launcher               LauncherConfig               `mapstructure:"launcher"`
	Database               DatabaseConfig               `mapstructure:"database"`
	NATS                   NATSConfig                   `mapstructure:"nats"`
	Events                 EventsConfig                 `mapstructure:"events"`
	Docker                 DockerConfig                 `mapstructure:"docker"`
	Agent                  AgentConfig                  `mapstructure:"agent"`
	Auth                   AuthConfig                   `mapstructure:"auth"`
	Logging                LoggingConfig                `mapstructure:"logging"`
	RepositoryDiscovery    RepositoryDiscoveryConfig    `mapstructure:"repositoryDiscovery"`
	Worktree               WorktreeConfig               `mapstructure:"worktree"`
	RepoClone              RepoCloneConfig              `mapstructure:"repoClone"`
	Debug                  DebugConfig                  `mapstructure:"debug"`
	Office                 OfficeConfig                 `mapstructure:"office"`
	Features               FeaturesConfig               `mapstructure:"features"`
	GitHubCredentialBroker GitHubCredentialBrokerConfig `mapstructure:"githubCredentialBroker"`
	Executors              ExecutorsConfig              `mapstructure:"executors"`
	Source                 ConfigSource                 `mapstructure:"-" json:"-"`
}

// TasksConfig contains task lifecycle startup limits.
type TasksConfig struct {
	PreparationTimeout time.Duration `mapstructure:"preparationTimeout"`
	// StallDetectionThreshold is the event-silence window after which the
	// session reconciliation sweep classifies an active session with no live
	// execution as stalled (issue #3712). The orphaned-session healing grace
	// window is twice this value.
	StallDetectionThreshold time.Duration `mapstructure:"stallDetectionThreshold"`
}

// CredentialsConfig contains operator-managed credential file settings.
type CredentialsConfig struct {
	File string `mapstructure:"file"`
}

// ExecutorsConfig contains executor-related startup settings.
type ExecutorsConfig struct {
	// SSHReachabilityIntervalSeconds is the raw configured value, not yet
	// clamped into the reachability package's own 15-3600 bound: 0 disables
	// the poller, and reachability.ClampInterval owns the rest of the
	// normalization at construction time.
	SSHReachabilityIntervalSeconds int `mapstructure:"sshReachabilityIntervalSeconds"`
}

// LimitsConfig contains process and protocol capacity limits.
type LimitsConfig struct {
	GHMaxConcurrent   int `mapstructure:"ghMaxConcurrent"`
	GitMaxConcurrent  int `mapstructure:"gitMaxConcurrent"`
	LSPMaxConnections int `mapstructure:"lspMaxConnections"`
}

// MessageQueueConfig contains prompt queue limits.
type MessageQueueConfig struct {
	MaxPerSession int `mapstructure:"maxPerSession"`
}

// AgentctlConfig contains settings owned by managed agentctl processes.
type AgentctlConfig struct {
	IdleTimeout               time.Duration `mapstructure:"idleTimeout"`
	IdleReaperInterval        time.Duration `mapstructure:"idleReaperInterval"`
	NotificationQueueCapacity int           `mapstructure:"notificationQueueCapacity"`

	// RecoveryDeadline is the single global bound covering adoption,
	// enumeration and reconstruction together during standalone agent
	// survival re-tracking at backend startup.
	RecoveryDeadline time.Duration `mapstructure:"recoveryDeadline"`
	// RecoveryReadTimeout and RecoveryReadRetries bound each read of a
	// reconstruction value from the adopted control server during re-tracking.
	RecoveryReadTimeout time.Duration `mapstructure:"recoveryReadTimeout"`
	RecoveryReadRetries int           `mapstructure:"recoveryReadRetries"`
	// UnownedPeriod is how long a standalone control server tolerates having
	// no owning backend before it stops its instances and exits.
	UnownedPeriod time.Duration `mapstructure:"unownedPeriod"`
	// DetachedEventLimit bounds the per-instance retained-event count while
	// a standalone control server has no owning backend attached.
	DetachedEventLimit int `mapstructure:"detachedEventLimit"`
}

// PlanningConfig contains planning service timing settings.
type PlanningConfig struct {
	CoalesceWindowMs int `mapstructure:"coalesceWindowMs"`
}

// ObservabilityConfig contains process-wide tracing settings.
type ObservabilityConfig struct {
	OTLPEndpoint string `mapstructure:"otlpEndpoint"`
}

// LauncherConfig contains settings used by the native launcher. The backend
// reads the same values so a selected file remains one source of truth.
type LauncherConfig struct {
	WebPort         int  `mapstructure:"webPort"`
	HealthTimeoutMs int  `mapstructure:"healthTimeoutMs"`
	NoBrowser       bool `mapstructure:"noBrowser"`
}

// GitHubCredentialBrokerConfig holds the externally reachable service URL
// used by managed remote executors. It is independent of GitHub App setup so
// PAT and named gh CLI workspaces can use remote executors.
type GitHubCredentialBrokerConfig struct {
	PublicBaseURL     string `mapstructure:"publicBaseUrl" json:"-"`
	ReissueSigningKey string `mapstructure:"reissueSigningKey" json:"-"`
}

func (c GitHubCredentialBrokerConfig) validate() error {
	if strings.TrimSpace(c.PublicBaseURL) == "" {
		return nil
	}
	return validatePublicBaseURL("githubCredentialBroker.publicBaseUrl", c.PublicBaseURL)
}

func validatePublicBaseURL(field, raw string) error {
	u, err := url.Parse(raw)
	if err != nil || !u.IsAbs() || u.Hostname() == "" {
		return fmt.Errorf("%s must be an absolute URL", field)
	}
	if u.User != nil || u.RawQuery != "" || u.Fragment != "" {
		return fmt.Errorf("%s must not include credentials, query, or fragment", field)
	}
	if u.Scheme != "https" && (u.Scheme != "http" || !IsLoopbackHost(u.Hostname())) {
		return fmt.Errorf("%s must use HTTPS outside loopback development", field)
	}
	return nil
}

// expandTilde expands a leading "~/" to the user's home directory.
// Returns the input unchanged if expansion is unnecessary or fails.
func expandTilde(p string) string {
	if !strings.HasPrefix(p, "~/") {
		return p
	}
	home, err := os.UserHomeDir()
	if err != nil {
		return p
	}
	return filepath.Join(home, p[2:])
}

// ResolvedHomeDir returns the Kandev root directory — the parent of data,
// tasks, worktrees, repos, sessions, quick-chat and lsp-servers.
//
// Resolution order:
//  1. KANDEV_HOME_DIR (explicit override — e.g. /data in Docker, /kandev in K8s,
//     or <repo>/.kandev-dev during local development).
//  2. ~/.kandev (default).
func (c *Config) ResolvedHomeDir() string {
	if c.HomeDir != "" {
		return expandTilde(c.HomeDir)
	}
	home, err := os.UserHomeDir()
	if err != nil {
		return kandevHomeSubdir
	}
	return filepath.Join(home, kandevHomeSubdir)
}

// ResolvedDataDir returns the base data directory (where the SQLite DB lives).
// Always <ResolvedHomeDir>/data — relocate via KANDEV_HOME_DIR, not a separate knob.
func (c *Config) ResolvedDataDir() string {
	return filepath.Join(c.ResolvedHomeDir(), "data")
}

// defaultServerHost is the wildcard host the server binds to when no host is
// configured — every interface.
const defaultServerHost = "0.0.0.0"

// ServerConfig holds HTTP server configuration.
type ServerConfig struct {
	// Host is the bind address. A single value (e.g. "127.0.0.1") behaves as
	// it always has; a comma-separated list (e.g. "127.0.0.1,100.64.0.1")
	// binds one listener per address. Empty means the wildcard default.
	//
	// Host carries the KANDEV_SERVER_HOST env override, so when it is set it
	// wins over Hosts to preserve env-over-file precedence (see ResolvedBinds).
	Host string `mapstructure:"host"`
	// Hosts is the YAML-array form of Host, for config files that prefer an
	// array to a comma-separated string. It is used only when Host is unset.
	Hosts          []string `mapstructure:"hosts"`
	TrustedProxies []string `mapstructure:"trustedProxies"`
	Port           int      `mapstructure:"port"`
	ReadTimeout    int      `mapstructure:"readTimeout"`  // in seconds
	WriteTimeout   int      `mapstructure:"writeTimeout"` // in seconds
	WebInternalURL string   `mapstructure:"webInternalUrl"`
	// WebTitlePrefix prefixes the browser tab title as "<prefix> Kandev" (for
	// example "TEST") so several Kandev instances are distinguishable in
	// adjacent browser tabs. Empty keeps the plain "Kandev" title.
	WebTitlePrefix string `mapstructure:"webTitlePrefix"`
}

// splitHosts splits a comma-separated host string, trimming whitespace and
// dropping empty entries.
func splitHosts(s string) []string {
	parts := strings.Split(s, ",")
	out := make([]string, 0, len(parts))
	for _, p := range parts {
		if p = strings.TrimSpace(p); p != "" {
			out = append(out, p)
		}
	}
	return out
}

// normalizeHost validates h and returns its canonical form plus whether it is a
// wildcard (binds every interface). IP addresses are canonicalized via
// net.ParseIP so equivalent forms dedupe (e.g. 0:0:0:0:0:0:0:1 and ::1); any
// unspecified IP (0.0.0.0, ::, or a longhand form) is treated as a wildcard.
// Hostnames are returned as-is. An invalid entry returns an error.
func normalizeHost(h string) (canonical string, wildcard bool, err error) {
	if ip := net.ParseIP(h); ip != nil {
		if ip.IsUnspecified() {
			return ip.String(), true, nil
		}
		return ip.String(), false, nil
	}
	if isValidHostname(h) {
		return h, false, nil
	}
	return "", false, fmt.Errorf("server bind host %q is not a valid IP address or hostname", h)
}

// isValidHostname reports whether h is a syntactically valid RFC 1123 hostname.
func isValidHostname(h string) bool {
	if len(h) == 0 || len(h) > 253 {
		return false
	}
	for _, label := range strings.Split(strings.TrimSuffix(h, "."), ".") {
		if !isValidHostnameLabel(label) {
			return false
		}
	}
	return true
}

// isValidHostnameLabel reports whether label is a valid single hostname label
// (letters, digits, and interior hyphens, 1–63 chars).
func isValidHostnameLabel(label string) bool {
	if len(label) == 0 || len(label) > 63 {
		return false
	}
	if label[0] == '-' || label[len(label)-1] == '-' {
		return false
	}
	for i := 0; i < len(label); i++ {
		c := label[i]
		if (c < 'a' || c > 'z') && (c < 'A' || c > 'Z') &&
			(c < '0' || c > '9') && c != '-' {
			return false
		}
	}
	return true
}

// IsLoopbackHost reports whether h refers only to the local loopback
// interface. A wildcard (empty/0.0.0.0/::) is NOT loopback because it also
// binds routable interfaces. Unresolvable hostnames are treated as
// non-loopback (fail-closed) so callers gating on "any non-loopback bind"
// don't under-report exposure.
func IsLoopbackHost(h string) bool {
	h = strings.TrimSpace(h)
	if h == "" {
		return false
	}
	if strings.EqualFold(h, "localhost") {
		return true
	}
	if ip := net.ParseIP(h); ip != nil {
		return ip.IsLoopback()
	}
	return false
}

// ResolvedBinds returns the de-duplicated, validated list of hosts the HTTP
// server should bind to. server.host (comma-separated string) takes precedence
// over server.hosts (YAML array) when set, because Host carries the
// KANDEV_SERVER_HOST env override and env must beat a config-file server.hosts
// (env-over-file precedence, and the desktop loopback contract). server.hosts
// is used only when host is unset. Whitespace is trimmed and empty/duplicate
// entries dropped, and IP addresses are canonicalized so equivalent forms
// dedupe. Every entry is validated before the set is collapsed, so an invalid
// host is rejected regardless of its position relative to a wildcard. If any
// entry is a wildcard (empty/0.0.0.0/:: or an unspecified IP) the whole set
// collapses to that single wildcard, since it already binds every interface. An
// empty result falls back to the wildcard default.
func (c *ServerConfig) ResolvedBinds() ([]string, error) {
	raw := splitHosts(c.Host)
	if len(raw) == 0 {
		for _, h := range c.Hosts {
			raw = append(raw, splitHosts(h)...)
		}
	}

	seen := make(map[string]struct{}, len(raw))
	out := make([]string, 0, len(raw))
	wildcard := ""
	for _, h := range raw {
		norm, isWild, err := normalizeHost(h)
		if err != nil {
			return nil, err
		}
		if isWild {
			if wildcard == "" {
				wildcard = norm
			}
			continue
		}
		if _, dup := seen[norm]; dup {
			continue
		}
		seen[norm] = struct{}{}
		out = append(out, norm)
	}
	if wildcard != "" {
		return []string{wildcard}, nil
	}
	if len(out) == 0 {
		return []string{defaultServerHost}, nil
	}
	return out, nil
}

// NonLoopbackBinds returns the resolved bind hosts that are not loopback-only.
// The sibling app-auth work uses this to decide whether to require auth (fail
// closed when the server is reachable off-box). A wildcard bind counts as
// non-loopback.
func (c *ServerConfig) NonLoopbackBinds() ([]string, error) {
	binds, err := c.ResolvedBinds()
	if err != nil {
		return nil, err
	}
	out := make([]string, 0, len(binds))
	for _, h := range binds {
		if !IsLoopbackHost(h) {
			out = append(out, h)
		}
	}
	return out, nil
}

// DatabaseConfig holds database connection configuration.
type DatabaseConfig struct {
	Driver   string `mapstructure:"driver"`
	Path     string `mapstructure:"path"`
	Host     string `mapstructure:"host"`
	Port     int    `mapstructure:"port"`
	User     string `mapstructure:"user"`
	Password string `mapstructure:"password"`
	DBName   string `mapstructure:"dbName"`
	SSLMode  string `mapstructure:"sslMode"`
	MaxConns int    `mapstructure:"maxConns"`
	MinConns int    `mapstructure:"minConns"`
}

// NATSConfig holds NATS messaging configuration.
type NATSConfig struct {
	URL           string `mapstructure:"url"`
	ClusterID     string `mapstructure:"clusterId"`
	ClientID      string `mapstructure:"clientId"`
	MaxReconnects int    `mapstructure:"maxReconnects"`
}

// EventsConfig holds event bus namespace configuration.
type EventsConfig struct {
	// Namespace isolates queue-group subscribers across deployments/instances.
	// Empty value means derive from runtime data identity.
	Namespace string `mapstructure:"namespace"`
}

// DockerConfig holds Docker client configuration.
type DockerConfig struct {
	// Enabled controls whether the Docker runtime is available for task execution.
	// When true and Docker is accessible, tasks can use Docker-based executors.
	// Default: true (Docker runtime is enabled if Docker is available)
	Enabled        bool   `mapstructure:"enabled"`
	Host           string `mapstructure:"host"`
	APIVersion     string `mapstructure:"apiVersion"`
	TLSVerify      bool   `mapstructure:"tlsVerify"`
	DefaultNetwork string `mapstructure:"defaultNetwork"`
	VolumeBasePath string `mapstructure:"volumeBasePath"`
}

// AuthConfig holds authentication configuration. Whether authentication is
// enforced is controlled by the `features.auth` runtime flag
// (KANDEV_FEATURES_AUTH), not here — these are only session-mechanics knobs.
type AuthConfig struct {
	JWTSecret     string `mapstructure:"jwtSecret"`
	TokenDuration int    `mapstructure:"tokenDuration"` // in seconds

	// SessionTTLHours is the sliding lifetime of a browser session. A session
	// is extended whenever it is used with less than TTL-24h remaining.
	SessionTTLHours int `mapstructure:"sessionTTLHours"`

	// CookieName is the session cookie base name. Empty (the default) means
	// the service uses the "kandev_session" base and port-scopes it from the
	// request host, isolating instances on one host (see
	// auth.Service.CookieNameForRequest). Only override for unusual
	// reverse-proxy setups that need a fixed cookie name; a custom value is
	// used verbatim (never port-suffixed) and disables automatic isolation.
	CookieName string `mapstructure:"cookieName"`
}

// OfficeConfig holds configuration for the office (autonomous agents) feature.
type OfficeConfig struct {
	// JWTSigningKey is the HMAC key used to sign agent runtime JWTs.
	// When empty, a random key is generated at startup — fine for dev, but
	// means every restart invalidates outstanding agent tokens. Production
	// deployments should set a stable value (e.g. via KANDEV_OFFICE_JWTSIGNINGKEY).
	JWTSigningKey   string `mapstructure:"jwtSigningKey"`
	SchedulerTickMs int    `mapstructure:"schedulerTickMs"`

	// The following back the launch-safety ceilings/budgets
	// (REQ-OFFICE-LAUNCH-SAFETY-001/003/004/005) and the backpressure
	// gate-failure escalation threshold (REQ-OFFICE-BACKPRESSURE-003.5).
	// Every one is boot-time-only, like SchedulerTickMs above: resolved
	// once at startup and passed into the owning repository/service via
	// its SetXxx method, not polled or overridable at runtime. A value
	// below the documented minimum (1, or 1 for PromotionAgeMinutes) is
	// replaced by that default and the resolved source is reported as
	// SourceDefault (applyPositiveIntEnv's existing behavior), matching
	// the "replaced by the default and logged at warn level" language the
	// acceptance criteria use for an out-of-range operator override.
	MaxConcurrentInstance  int `mapstructure:"maxConcurrentInstance"`
	MaxConcurrentWorkspace int `mapstructure:"maxConcurrentWorkspace"`
	WorkspaceBudgetPerHour int `mapstructure:"workspaceBudgetPerHour"`
	RoutineBudgetPerHour   int `mapstructure:"routineBudgetPerHour"`
	// PromotionAgeMinutes is REQ-OFFICE-BACKPRESSURE-002.1's age-based
	// priority promotion period, in minutes (converted to
	// runssqlite.ClaimSafetyLimits.PromotionAge, a time.Duration, at the
	// wiring site — the catalog only carries plain ints).
	PromotionAgeMinutes  int `mapstructure:"promotionAgeMinutes"`
	MaxCausationDepth    int `mapstructure:"maxCausationDepth"`
	SelfTriggerAllowance int `mapstructure:"selfTriggerAllowance"`
	// SelfTriggerTotalAllowance is the reason-independent sibling of
	// SelfTriggerAllowance (AC-OFFICE-LAUNCH-SAFETY-004.8): it may be
	// configured below SelfTriggerAllowance, in which case it is the
	// binding limit and the per-reason allowance becomes unreachable.
	SelfTriggerTotalAllowance int `mapstructure:"selfTriggerTotalAllowance"`
	GateFailureThreshold      int `mapstructure:"gateFailureThreshold"`
}

// FeaturesConfig is the typed wire/config shape for runtime feature flags.
// Every new release toggle defaults to false so production binaries ship with
// new work hidden until a deployment explicitly opts in (env var, e.g.
// KANDEV_FEATURES_OFFICE=true). The runtimeflags package owns metadata and
// typed config bindings.
//
// The struct doubles as the wire shape for GET /api/v1/features — `json` tags
// keep the field names lowercase and the handler in helpers.go just calls
// `c.JSON(200, p.features)` so new fields are picked up automatically.
//
// See docs/decisions/0007-runtime-feature-flags.md for the pattern and rollout policy.
type FeaturesConfig struct {
	// LSPBrowserContinuity gates runtime-owned language-server leases that stay
	// connected across browser attachment loss. Off in every embedded profile.
	LSPBrowserContinuity bool `mapstructure:"lsp_browser_continuity" json:"lspBrowserContinuity"`

	// Office gates the autonomous-agent feature: backend service construction,
	// HTTP/WS route registration, and frontend nav/route visibility.
	Office bool `mapstructure:"office" json:"office"`

	// Auth is the on/off switch for opt-in authentication and per-user
	// workspaces. When on, every visitor must sign in (the first becomes the
	// admin via a setup wizard) and workspaces are private per user; the
	// Users/Account settings surfaces also become visible. Set via the
	// runtime feature toggle KANDEV_FEATURES_AUTH (Settings > System > Feature
	// Toggles). Off by default so kandev stays single-user until a deployment
	// opts in.
	Auth bool `mapstructure:"auth" json:"auth"`

	// Canvases gates agent-authored plugin web applications and their task and
	// workspace surfaces. It remains off in every shipped profile until the
	// isolated runtime and lifecycle are ready for opt-in use.
	Canvases bool `mapstructure:"canvases" json:"canvases"`

	// MultiTenancy gates organizations: a tenant boundary above users, where
	// every user belongs to exactly one org and cross-org reach is a bug
	// rather than a permission level. It requires Auth; enabling it without
	// authentication is refused at startup, because a tenant boundary with no
	// identity behind it is not a boundary. Set via the runtime feature toggle
	// KANDEV_FEATURES_MULTI_TENANCY. Off in every shipped profile.
	MultiTenancy bool `mapstructure:"multi_tenancy" json:"multiTenancy"`

	// DynamicAgentRouting gates dynamic profile configuration, execution
	// routing, and the shared route health service. It is disabled in every
	// embedded profile until the complete feature is ready.
	DynamicAgentRouting bool `mapstructure:"dynamic_agent_routing" json:"dynamicAgentRouting"`

	// ClaudeBackgroundPromptHandoff gates the high-risk experiment that lets a
	// claude-acp session accept a successor prompt after an adapter-attested
	// foreground handoff while background work remains live. It is off in every
	// embedded profile and must fail closed for every other provider.
	ClaudeBackgroundPromptHandoff bool `mapstructure:"claude_background_prompt_handoff" json:"claudeBackgroundPromptHandoff"`

	// ClaudeMidTurnSteering gates the high-risk experiment that delivers operator
	// input into a turn that is still generating, for an agent that advertised
	// prompt queueing. It is independent of ClaudeBackgroundPromptHandoff: that
	// flag covers the foreground-idle handoff, this one covers a foreground that
	// has not yielded. Off in every embedded profile, and it remains the
	// kill-switch after rollout because the agent-side fold is undocumented and
	// can regress without notice.
	ClaudeMidTurnSteering bool `mapstructure:"claude_mid_turn_steering" json:"claudeMidTurnSteering"`

	// OfficeSessionIdentity keys an Office task's session identity on the run's
	// own agent instead of the task's runner seat, and binds an agent's
	// decision re-evaluation to its own calling session instead of the task's
	// most-recently-started session. On in every embedded profile; it remains a
	// high-risk, path-scoped change to durable session identity. A live
	// (task_id, agent_profile_id) pair is guarded in-transaction on the office
	// session creation path, not by a table-level constraint, and pre-existing
	// duplicate rows stay safe by selection, not migration. The toggle remains a
	// kill switch that restores runner-seat binding and task-active-session
	// decision re-evaluation when disabled.
	OfficeSessionIdentity bool `mapstructure:"office_session_identity" json:"officeSessionIdentity"`

	// NeedsYouInbox gates the Needs-you Inbox: a workspace-scoped sidebar
	// destination, independent of Office, listing exactly the answerable
	// clarification bundles for the active workspace. Off in prod until the
	// feature is user-ready.
	NeedsYouInbox bool `mapstructure:"needs_you_inbox" json:"needsYouInbox"`

	// AgentSurvival lets a worktree or local-executor agent session survive a
	// backend restart by adopting its still-running standalone control server
	// instead of killing it. Off in every embedded profile, and unavailable on
	// Windows (survival trades the platform's kill-on-job-close safeguard for
	// an adoption handshake, which is untested there).
	AgentSurvival bool `mapstructure:"agent_survival" json:"agentSurvival"`
}

// LoggingConfig holds logging configuration.
type LoggingConfig struct {
	Level  string `mapstructure:"level"`
	Format string `mapstructure:"format"`
}

// RepositoryDiscoveryConfig holds configuration for local repository scanning.
type RepositoryDiscoveryConfig struct {
	Roots    []string `mapstructure:"roots"`
	MaxDepth int      `mapstructure:"maxDepth"`
}

// WorktreeConfig holds Git worktree configuration for concurrent agent execution.
type WorktreeConfig struct {
	Enabled             bool   `mapstructure:"enabled"`             // Enable worktree mode
	DefaultBranch       string `mapstructure:"defaultBranch"`       // Default base branch (default: main)
	CleanupOnRemove     bool   `mapstructure:"cleanupOnRemove"`     // Remove worktree directory on task deletion
	FetchTimeoutSeconds int    `mapstructure:"fetchTimeoutSeconds"` // Git fetch timeout before worktree creation
	PullTimeoutSeconds  int    `mapstructure:"pullTimeoutSeconds"`  // Git pull timeout before worktree creation
}

// RepoCloneConfig holds configuration for automatic repository cloning.
type RepoCloneConfig struct {
	BasePath string `mapstructure:"basePath"` // Base directory for cloned repos (default: ~/.kandev/repos)
}

// DebugConfig holds debug/profiling configuration.
type DebugConfig struct {
	// DevMode enables all developer-only endpoints (pprof, memory, debug export).
	// Controlled via KANDEV_DEBUG_DEV_MODE env var. Default: false.
	DevMode bool `mapstructure:"devMode"`

	// PprofEnabled is a legacy alias — if set, it also enables DevMode.
	// Controlled via KANDEV_DEBUG_PPROF_ENABLED env var. Default: false.
	PprofEnabled bool `mapstructure:"pprofEnabled"`
}

// AgentConfig holds agent runtime configuration.
// Note: Runtime selection is now per-task based on executor type, not global.
// The Standalone runtime (agentctl) always runs as a core service.
// Docker runtime is available when docker.enabled=true.
type AgentConfig struct {
	// StandaloneHost is the host where standalone agentctl is running (default: 127.0.0.1)
	StandaloneHost string `mapstructure:"standaloneHost"`

	// StandalonePort is the control port for standalone agentctl (default: 39429)
	StandalonePort int `mapstructure:"standalonePort"`

	// StandaloneAuthToken is the single credential that authenticates both
	// the agentctl *control server* (instance create/list/delete, health,
	// ownership rotate/confirm) and every per-instance agentctl server it
	// supervises (/agent/stream, file tree, shell, ...), per design 01
	// "Single driver" (AC-EXECUTORS-CONTROL-OWNERSHIP-002.6). After adopting
	// a surviving control server it holds the freshly rotated credential
	// (AC-EXECUTORS-CONTROL-OWNERSHIP-002); use it for every client built
	// against this control server or any instance it supervises. Set at
	// runtime after agentctl starts; not persisted in config files.
	StandaloneAuthToken string `mapstructure:"-"`

	// StandalonePID is the OS process id of the standalone agentctl control-server
	// this backend spawned. Set at runtime after agentctl starts (from the
	// launcher); not persisted in config files. Used as the host-local liveness
	// handle recorded in executors_running.local_pid for local/standalone rows.
	StandalonePID int `mapstructure:"-"`
}

// ReadTimeoutDuration returns the read timeout as a time.Duration.
func (s *ServerConfig) ReadTimeoutDuration() time.Duration {
	return time.Duration(s.ReadTimeout) * time.Second
}

// WriteTimeoutDuration returns the write timeout as a time.Duration.
func (s *ServerConfig) WriteTimeoutDuration() time.Duration {
	return time.Duration(s.WriteTimeout) * time.Second
}

// TokenDurationTime returns the token duration as a time.Duration.
func (a *AuthConfig) TokenDurationTime() time.Duration {
	return time.Duration(a.TokenDuration) * time.Second
}

// detectDefaultLogFormat returns the appropriate log format based on environment.
// Returns "json" if running in Kubernetes or other production environments.
// Returns "text" for terminal/development use (human-readable console format).
func detectDefaultLogFormat() string {
	// Check if running in Kubernetes
	if os.Getenv("KUBERNETES_SERVICE_HOST") != "" {
		return "json"
	}

	// Check for explicit production environment
	if env := os.Getenv("KANDEV_ENV"); env == "production" || env == "prod" {
		return "json"
	}

	// Default to text format for terminal use (more readable than JSON)
	return "text"
}

// setDefaults configures default values for all configuration options.
func setDefaults(v *viper.Viper) {
	// Server defaults. Host defaults to empty (not the wildcard) so an unset
	// host is distinguishable from an explicit one: ResolvedBinds falls back to
	// server.hosts only when host is unset, and empty resolves to the wildcard
	// default. This keeps KANDEV_SERVER_HOST winning over a config-file
	// server.hosts.
	v.SetDefault("server.host", "")
	v.SetDefault("server.port", ports.Backend)
	v.SetDefault("server.readTimeout", 30)
	v.SetDefault("server.writeTimeout", 30)
	v.SetDefault("server.webInternalUrl", "")
	v.SetDefault("server.webTitlePrefix", "")

	// HomeDir default — empty means resolve from KANDEV_HOME_DIR env or ~/.kandev
	v.SetDefault("homeDir", "")

	// Database defaults
	v.SetDefault("database.driver", "sqlite")
	v.SetDefault("database.path", "")
	v.SetDefault("database.host", "localhost")
	v.SetDefault("database.port", 5432)
	v.SetDefault("database.user", "kandev")
	v.SetDefault("database.password", "")
	v.SetDefault("database.dbName", "kandev")
	v.SetDefault("database.sslMode", "disable")
	v.SetDefault("database.maxConns", 25)
	v.SetDefault("database.minConns", 5)

	// NATS defaults - empty URL means use in-memory event bus
	v.SetDefault("nats.url", "")
	v.SetDefault("nats.clusterId", "kandev-cluster")
	v.SetDefault("nats.clientId", "kandev-client")
	v.SetDefault("nats.maxReconnects", 10)

	// Events defaults
	v.SetDefault("events.namespace", "")

	// Docker defaults — platform-aware host and volume path
	v.SetDefault("docker.enabled", true) // Docker runtime enabled by default if Docker is available
	v.SetDefault("docker.host", DefaultDockerHost())
	v.SetDefault("docker.apiVersion", "") // Empty = auto-negotiate with daemon
	v.SetDefault("docker.tlsVerify", false)
	v.SetDefault("docker.defaultNetwork", "kandev-network")
	v.SetDefault("docker.volumeBasePath", defaultDockerVolumePath())

	// Agent defaults (runtime selection is now per-task based on executor type)
	//
	// 127.0.0.1 instead of "localhost": localhost resolution can select an IPv6
	// loopback address before an IPv4 address. The explicit IPv4 loopback avoids
	// address-resolution variance when host utility health checks run against
	// agentctl bound IPv4-only and fail with
	// "dial tcp [::1]:41001: connect: connection refused" whenever agentctl is
	// bound IPv4-only (e.g. auth-disabled loopback binds), spinning the
	// "host utility instance unhealthy; recreating" loop. The loopback
	// address is explicit and unambiguous; operators with a non-loopback
	// control plane can still override via KANDEV_AGENT_STANDALONE_HOST.
	v.SetDefault("agent.standaloneHost", "127.0.0.1")
	v.SetDefault("agent.standalonePort", ports.AgentCtl)

	// Auth defaults. auth.cookieName defaults to empty on purpose: the auth
	// service keeps the "kandev_session" base fallback internally and
	// port-scopes it from the request host, so an empty default must not be
	// seeded with a concrete name or the suffixing would never fire in
	// production. A non-empty configured value is used verbatim.
	v.SetDefault("auth.jwtSecret", "")
	v.SetDefault("auth.tokenDuration", 3600)  // 1 hour
	v.SetDefault("auth.sessionTTLHours", 720) // 30 days, sliding
	v.SetDefault("auth.cookieName", "")

	// Office defaults
	v.SetDefault("office.jwtSigningKey", "")

	// Feature-flag defaults live in ./features.yaml (symlinked to
	// apps/backend/internal/features/features.yaml). LoadWithPath applies
	// them via features.ApplyDefaults after this function returns so the
	// embedded YAML, not a Go literal, is the source of truth. Env vars
	// (KANDEV_FEATURES_<NAME>) and the deployment's config.yaml still
	// override. See docs/decisions/0007-runtime-feature-flags.md.

	// Logging defaults
	v.SetDefault("logging.level", "info")
	v.SetDefault("logging.format", detectDefaultLogFormat())

	// Repository discovery defaults
	v.SetDefault("repositoryDiscovery.roots", []string{})
	v.SetDefault("repositoryDiscovery.maxDepth", 5)

	// Worktree defaults
	v.SetDefault("worktree.enabled", true)
	v.SetDefault("worktree.defaultBranch", "main")
	v.SetDefault("worktree.cleanupOnRemove", true)
	v.SetDefault("worktree.fetchTimeoutSeconds", 60)
	v.SetDefault("worktree.pullTimeoutSeconds", 60)

	// RepoClone defaults
	v.SetDefault("repoClone.basePath", "")

	// Debug defaults
	v.SetDefault("debug.pprofEnabled", false)
}

// DefaultDockerHost returns the platform-appropriate Docker socket path.
// Respects DOCKER_HOST env var as override (standard Docker convention).
func DefaultDockerHost() string {
	if host := os.Getenv("DOCKER_HOST"); host != "" {
		return host
	}
	if runtime.GOOS == "windows" {
		return "npipe:////./pipe/docker_engine"
	}
	return "unix:///var/run/docker.sock"
}

// defaultDockerVolumePath returns the platform-appropriate volume base path.
func defaultDockerVolumePath() string {
	if runtime.GOOS == "windows" {
		localAppData := os.Getenv("LOCALAPPDATA")
		if localAppData == "" {
			localAppData = filepath.Join(os.Getenv("USERPROFILE"), "AppData", "Local")
		}
		return filepath.Join(localAppData, "kandev", "volumes")
	}
	return "/var/lib/kandev/volumes"
}

// Load reads configuration from environment variables, config file, and defaults.
// Environment variables use the prefix KANDEV_ with snake_case naming.
// Config file should be named config.yaml and placed in the current directory or /etc/kandev/.
func Load() (*Config, error) {
	return LoadWithHome("")
}

// LoadWithHome reads the selected configuration while using homeDir as the
// bootstrap directory for home-file discovery. The override affects file
// selection only; environment variables still retain their normal precedence
// over values read from the selected file.
func LoadWithHome(homeDir string) (*Config, error) {
	if path := strings.TrimSpace(os.Getenv(InternalConfigFileEnv)); path != "" {
		return loadWithPath(path, homeDir)
	}
	return loadWithPath("", homeDir)
}

// LoadWithPath reads configuration from the specified path or default locations.
func LoadWithPath(configPath string) (*Config, error) {
	return loadWithPath(configPath, "")
}

func loadWithPath(configPath, homeDir string) (*Config, error) {
	v := viper.New()

	profileDefaults, err := profiles.EnvironmentDefaults()
	if err != nil {
		return nil, fmt.Errorf("read profile defaults: %w", err)
	}

	// Set defaults next. setDefaults seeds non-feature config
	// (server, database, logging, …); feature-flag defaults flow
	// through EnvironmentDefaults and AutomaticEnv below.
	setDefaults(v)

	// Seed Viper's features.* keyspace from profiles.yaml so the
	// typed Config struct populates correctly even in tests that
	// bypass AutomaticEnv. AutomaticEnv still wins at runtime.
	flags, err := profiles.FeatureFlagDefaults()
	if err != nil {
		return nil, fmt.Errorf("read feature flag defaults: %w", err)
	}
	for name, value := range flags {
		v.SetDefault("features."+name, value == "true")
	}
	setProfileDefaults(v, profileDefaults)

	// Configure environment variables
	v.SetEnvPrefix("KANDEV")
	v.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
	v.AutomaticEnv()

	bindCatalogEnvironment(v)
	// camelCase key, so AutomaticEnv would expose the undocumented
	// KANDEV_AUTH_COOKIENAME; the canonical override is KANDEV_AUTH_COOKIE_NAME.
	_ = v.BindEnv("auth.cookieName", "KANDEV_AUTH_COOKIE_NAME")
	_ = v.BindEnv(
		"githubCredentialBroker.publicBaseUrl",
		"KANDEV_GITHUB_CREDENTIAL_BROKER_PUBLIC_BASE_URL",
	)
	_ = v.BindEnv(
		"githubCredentialBroker.reissueSigningKey",
		"KANDEV_GITHUB_CREDENTIAL_BROKER_REISSUE_SIGNING_KEY",
	)

	selection, found, err := selectConfigFile(configPath, homeDir)
	if err != nil {
		return nil, fmt.Errorf("select configuration file: %w", err)
	}
	if found {
		if err := readSelectedConfig(v, selection); err != nil {
			return nil, err
		}
	}
	yamlKeys := configKeys(v)
	envSnapshot := environmentSnapshot()

	var cfg Config
	if err := decodeConfig(v, &cfg); err != nil {
		if found {
			return nil, fmt.Errorf("error unmarshaling config file %q: %w", selection.path, err)
		}
		return nil, fmt.Errorf("error unmarshaling config: %w", err)
	}
	sources := applyStartupDefaultsAndEnvironment(&cfg, yamlKeys, profileDefaults, envSnapshot)
	if err := applySurvivalRecoveryEnv(&cfg, envSnapshot, sources); err != nil {
		return nil, fmt.Errorf("config validation failed: %w", err)
	}
	warnings := inspectSecretPermissions(selection, v)
	warnings = append(warnings, clampOfficeLaunchSafetyConfig(&cfg)...)
	cfg.Source = buildConfigSource(selection, v, sources, warnings)

	if err := validateStartupSettings(&cfg); err != nil {
		if found {
			return nil, fmt.Errorf("config validation failed for %q: %w", selection.path, err)
		}
		return nil, fmt.Errorf("config validation failed: %w", err)
	}

	if err := validate(&cfg); err != nil {
		if found {
			return nil, fmt.Errorf("config validation failed for %q: %w", selection.path, err)
		}
		return nil, fmt.Errorf("config validation failed: %w", err)
	}

	return &cfg, nil
}

// validate checks that all required configuration fields are set.
// In development mode (default), most fields are optional.
func validate(cfg *Config) error {
	var errs []string

	// Server validation - always required
	if cfg.Server.Port <= 0 || cfg.Server.Port > 65535 {
		errs = append(errs, "server.port must be between 1 and 65535")
	}
	if _, err := cfg.Server.ResolvedBinds(); err != nil {
		errs = append(errs, err.Error())
	}

	// Database validation. Normalize the driver in place so downstream
	// case-sensitive comparisons (and the postgres-only branch below) see
	// a canonical value.
	cfg.Database.Driver = strings.ToLower(cfg.Database.Driver)
	validDrivers := map[string]bool{"sqlite": true, "postgres": true}
	if !validDrivers[cfg.Database.Driver] {
		errs = append(errs, "database.driver must be one of: sqlite, postgres")
	}
	if cfg.Database.Driver == "postgres" {
		if cfg.Database.Port <= 0 || cfg.Database.Port > 65535 {
			errs = append(errs, "database.port must be between 1 and 65535")
		}
		if cfg.Database.User == "" {
			errs = append(errs, "database.user is required for postgres driver")
		}
		if cfg.Database.DBName == "" {
			errs = append(errs, "database.dbName is required for postgres driver")
		}
		validSSLModes := map[string]bool{
			"disable": true, "require": true, "verify-ca": true, "verify-full": true,
		}
		if !validSSLModes[strings.ToLower(cfg.Database.SSLMode)] {
			errs = append(errs, "database.sslMode must be one of: disable, require, verify-ca, verify-full")
		}
	}

	// NATS validation - optional (uses in-memory event bus if not set)
	// No validation needed - empty URL means use in-memory

	// Docker validation - optional (agent features disabled if not available)
	// No validation needed - will gracefully degrade

	// Auth validation - generate random secret if not set (dev mode)
	if cfg.Auth.JWTSecret == "" {
		cfg.Auth.JWTSecret = generateDevSecret()
	}
	if cfg.Auth.TokenDuration <= 0 {
		errs = append(errs, "auth.tokenDuration must be positive")
	}

	// Logging validation
	validLevels := map[string]bool{"debug": true, "info": true, "warn": true, "error": true}
	if !validLevels[strings.ToLower(cfg.Logging.Level)] {
		errs = append(errs, "logging.level must be one of: debug, info, warn, error")
	}
	validFormats := map[string]bool{"json": true, "text": true}
	if !validFormats[strings.ToLower(cfg.Logging.Format)] {
		errs = append(errs, "logging.format must be one of: json, text")
	}

	if cfg.RepositoryDiscovery.MaxDepth <= 0 {
		errs = append(errs, "repositoryDiscovery.maxDepth must be positive")
	}

	if err := cfg.GitHubCredentialBroker.validate(); err != nil {
		errs = append(errs, err.Error())
	}

	if len(errs) > 0 {
		return fmt.Errorf("%s", strings.Join(errs, "; "))
	}

	return nil
}

// DSN returns the PostgreSQL connection string.
func (d *DatabaseConfig) DSN() string {
	return fmt.Sprintf(
		"host=%s port=%d user=%s password=%s dbname=%s sslmode=%s",
		d.Host, d.Port, d.User, d.Password, d.DBName, d.SSLMode,
	)
}

// generateDevSecret generates a random secret for development mode.
func generateDevSecret() string {
	// Use a fixed dev secret with a warning prefix
	// In production, users should set KANDEV_AUTH_JWTSECRET
	return "dev-secret-change-in-production-" + fmt.Sprintf("%d", time.Now().UnixNano())
}