package config

import (
	"fmt"
	"strconv"
	"strings"
	"time"
)

// Config is the full harness.toml surface. Defaults live in Default();
// apply() overlays the parsed document; Validate() enforces invariants.
type Config struct {
	Vertical  string
	WorkRoot  string
	ReportDir string
	Loop      LoopConfig
	Redmine   RedmineConfig
	LiteLLM   LiteLLMConfig
	Models    ModelsConfig
	Bash      BashConfig
	Demo      DemoConfig
	Events    EventsConfig
	Serve     ServeConfig
	KeyProxy  KeyProxyConfig
	Gitea     GiteaConfig
	Quota     QuotaConfig
	Resources ResourcesConfig
}

// LoopConfig is both the per-turn bound and the `harness loop` daemon
// cadence + state location.
type LoopConfig struct {
	MaxRounds        int
	PollIntervalSecs int    // loop: Redmine scan interval (default 120)
	StateDir         string // loop: append-only loop.jsonl + dedup index
}

type RedmineConfig struct {
	URL          string
	KeyRef       string
	ScopeQuery   string
	ScopeQueryID int
	ClassField   string
	DefaultClass string
	Limit        int
	// StatusMap: issue status name -> status name to set after a REPORT
	// lands (loop path only; e.g. [redmine.status_map] "In Progress" =
	// "Done"). Empty map = leave status alone.
	StatusMap map[string]string
}

type LiteLLMConfig struct {
	BaseURL     string
	KeyRef      string
	TimeoutSecs int
	MaxRetries  int
}

type ModelsConfig struct {
	// Tiers maps tier aliases (mopac-study, ...) to concrete proxy models.
	Tiers map[string]string
	// Classes maps task classes (study, code, ...) to tier aliases.
	Classes map[string]string
	// DefaultTier is used when a task carries no class.
	DefaultTier string
}

type BashConfig struct {
	Enabled        bool
	Allow          []string
	Deny           []string
	DefaultAllow   bool
	TimeoutSecs    int
	MaxOutputBytes int
}

type DemoConfig struct {
	ID      string
	Subject string
	Prompt  string
	Class   string
}

// ServeConfig is the `harness serve` OpenAI-compatible front door (the
// OpenWebUI connection). Own port — coexists with [events].
type ServeConfig struct {
	Listen        string   // bind address (default ":8090"; publish via docker -p)
	VKeyRef       string   // bearer vkey ref; the key OWUI connections present
	EnabledModels []string // optional subset of the catalog (mopac-<class>); empty = all classes
}

// KeyProxyConfig is the ukrrs/mopac-keyproxy resolve hop: mpk: key refs
// POST here. All hosts/paths live in this config, never in code.
type KeyProxyConfig struct {
	URL          string // hop base url (e.g. http://127.0.0.1:8082)
	TokenRef     string // local ref (env:/file:/literal:) holding the bearer token
	CacheTTLSecs int    // in-memory mpk resolution cache (default 60)
}

// GiteaConfig is the optional REPORT-commit step (off by default). When
// commit_reports is true the loop commits each REPORT file to the
// configured repo right after writing it.
type GiteaConfig struct {
	URL           string
	KeyRef        string
	Owner         string
	Repo          string
	Branch        string
	CommitReports bool
}

// QuotaConfig is the z.ai coding-plan quota gate: bucket limits, polling,
// back-pressure thresholds, the peak-hour schedule, and the optional
// shared-state hop (redis container) for multi-instance coordination.
// The quota gate NEVER hard-fails the loop; when it cannot see quota state
// it degrades to permissive (allow) with a logged caveat.
type QuotaConfig struct {
	Enabled bool

	// Account labels this instance's z.ai plan in the shared state so the
	// nine harness instances across two hosts do not cross-contaminate.
	Account string

	// Plan credit buckets (docs: Lite 2k/10k, Pro 12k/60k, Max 28k/140k).
	Plan5hCredits     float64
	PlanWeeklyCredits float64

	// UsageURL + KeyRef: the z.ai usage/limits endpoint (bearer auth; the
	// key is a ref, resolved at call time, never logged). Empty = no
	// upstream polling; the gate runs on locally estimated consumption.
	UsageURL         string
	KeyRef           string
	PollIntervalSecs int

	// Back-pressure thresholds, percent of bucket used. defer_at: heavy
	// classes defer, flash-tier continue. block_at: everything defers.
	DeferAtPct float64
	BlockAtPct float64

	// Peak window (z.ai charges 3x-ish during peak; off-peak is 50% off).
	// Defaults verified against the z.ai docs: peak = Mon-Fri 14:00-18:00
	// Singapore (UTC+8) == 01:00-05:00 America/Chicago in winter.
	PeakStart       string // "HH:MM" in Timezone
	PeakEnd         string
	Timezone        string // IANA name; default America/Chicago (CST)
	PeakWeekdaysOnly bool
	// PeakClasses: task classes allowed to run inside the peak window
	// (the LLM-lite / flash tier); every other class defers with a reason.
	PeakClasses []string

	// RedisURL: shared quota state for all instances of this account
	// (docker container; no host packages). Empty = local-only estimate.
	RedisURL string
}

// ResourcesConfig is the read-only system resource gate (Redmine 491):
// load average, memory available, work-root disk free, IO pressure. The
// loop defers dispatch while the host is busy; enforcement via cgroups is
// a deploy-time concern (see the runbook in README).
type ResourcesConfig struct {
	Enabled           bool
	MaxLoadAvg        float64 // 1m load average
	MinMemAvailableMB float64
	MinDiskFreeMB     float64 // work_root filesystem
	MaxIODelayPct     float64 // /proc/pressure/io "some avg60" percent
	// ProcRoot/SysRoot are seams for tests; default /proc and /sys.
	ProcRoot string
	SysRoot  string
}

// EventsConfig is the `harness events` webhook receiver surface.
type EventsConfig struct {
	Listen    string            // bind address (publish via docker -p)
	StateDir  string            // append-only events.jsonl + dedup index
	Redmine   EventSourceConfig
	Discourse EventSourceConfig
	Gitea     EventSourceConfig
}

// EventSourceConfig is one provider's webhook verification setup. Secrets
// are refs only (env:/file:/literal:); values never live in this file, are
// never logged, and never reach the event log.
type EventSourceConfig struct {
	SecretRef    string
	SecretHeader string // shared-secret header name; gitea ignores it (HMAC)
}

// Default returns the built-in defaults for every field.
func Default() *Config {
	return &Config{
		WorkRoot:  ".",
		ReportDir: "reports",
		Loop: LoopConfig{
			MaxRounds:        8,
			PollIntervalSecs: 120,
			StateDir:         "state/loop",
		},
		Redmine: RedmineConfig{
			ClassField:   "Class",
			DefaultClass: "primary",
			Limit:        50,
			StatusMap:    map[string]string{},
		},
		LiteLLM: LiteLLMConfig{TimeoutSecs: 120, MaxRetries: 2},
		Models: ModelsConfig{
			Tiers:       map[string]string{},
			Classes:     map[string]string{},
			DefaultTier: "mopac-primary",
		},
		Bash: BashConfig{Enabled: true, TimeoutSecs: 60, MaxOutputBytes: 100_000},
		Events: EventsConfig{
			Listen:   ":4100",
			StateDir: "state/events",
			Redmine: EventSourceConfig{
				SecretHeader: "X-Redmine-Webhook-Secret",
			},
			Discourse: EventSourceConfig{
				SecretHeader: "X-Discourse-Webhook-Secret",
			},
		},
		Serve:    ServeConfig{Listen: ":8090"},
		KeyProxy: KeyProxyConfig{CacheTTLSecs: 60},
		Quota: QuotaConfig{
			Enabled:          false, // opt-in per instance until verified live
			Plan5hCredits:   28000, // Max plan
			PlanWeeklyCredits: 140000,
			PollIntervalSecs: 300,
			DeferAtPct:       85,
			BlockAtPct:       95,
			PeakStart:        "01:00",
			PeakEnd:          "05:00",
			Timezone:         "America/Chicago",
			PeakWeekdaysOnly: true,
			PeakClasses:      []string{"study", "read"},
		},
		Resources: ResourcesConfig{
			Enabled:           false,
			MaxLoadAvg:        6.0,
			MinMemAvailableMB: 2048,
			MinDiskFreeMB:     5120,
			MaxIODelayPct:     90.0,
			ProcRoot:          "/proc",
			SysRoot:           "/sys",
		},
		Demo: DemoConfig{
			ID:      "demo-1",
			Subject: "MVP demo: GLM self-description",
			Prompt:  "tell me about yourself",
			Class:   "primary",
		},
	}
}

func (c *Config) apply(doc TOMLDoc) error {
	if v, ok := doc.String("vertical"); ok {
		c.Vertical = v
	}
	if v, ok := doc.String("work_root"); ok {
		c.WorkRoot = v
	}
	if v, ok := doc.String("report_dir"); ok {
		c.ReportDir = v
	}
	if v, ok := doc.Table("loop").Int("max_rounds"); ok {
		c.Loop.MaxRounds = int(v)
	}
	if v, ok := doc.Table("loop").Int("poll_interval_secs"); ok {
		c.Loop.PollIntervalSecs = int(v)
	}
	if v, ok := doc.Table("loop").String("state_dir"); ok {
		c.Loop.StateDir = v
	}

	rm := doc.Table("redmine")
	if v, ok := rm.String("url"); ok {
		c.Redmine.URL = v
	}
	if v, ok := rm.String("key_ref"); ok {
		c.Redmine.KeyRef = v
	}
	if v, ok := rm.String("scope_query"); ok {
		c.Redmine.ScopeQuery = v
	}
	if v, ok := rm.Int("scope_query_id"); ok {
		c.Redmine.ScopeQueryID = int(v)
	}
	if v, ok := rm.String("class_field"); ok {
		c.Redmine.ClassField = v
	}
	if v, ok := rm.String("default_class"); ok {
		c.Redmine.DefaultClass = v
	}
	if v, ok := rm.Int("limit"); ok {
		c.Redmine.Limit = int(v)
	}
	for _, k := range doc.Table("redmine", "status_map").Keys() {
		if v, ok := doc.Table("redmine", "status_map").String(k); ok {
			if c.Redmine.StatusMap == nil {
				c.Redmine.StatusMap = map[string]string{}
			}
			c.Redmine.StatusMap[k] = v
		}
	}

	lt := doc.Table("litellm")
	if v, ok := lt.String("base_url"); ok {
		c.LiteLLM.BaseURL = v
	}
	if v, ok := lt.String("key_ref"); ok {
		c.LiteLLM.KeyRef = v
	}
	if v, ok := lt.Int("timeout_secs"); ok {
		c.LiteLLM.TimeoutSecs = int(v)
	}
	if v, ok := lt.Int("max_retries"); ok {
		c.LiteLLM.MaxRetries = int(v)
	}

	md := doc.Table("models")
	for _, k := range md.Keys() {
		if k == "default_tier" {
			continue
		}
		if v, ok := md.String(k); ok {
			c.Models.Tiers[k] = v
		}
	}
	if v, ok := md.String("default_tier"); ok {
		c.Models.DefaultTier = v
	}
	cls := doc.Table("models", "classes")
	for _, k := range cls.Keys() {
		if v, ok := cls.String(k); ok {
			c.Models.Classes[k] = v
		}
	}

	bt := doc.Table("tools", "bash")
	if v, ok := bt.Bool("enabled"); ok {
		c.Bash.Enabled = v
	}
	if v, ok := bt.StringList("allow"); ok {
		c.Bash.Allow = v
	}
	if v, ok := bt.StringList("deny"); ok {
		c.Bash.Deny = v
	}
	if v, ok := bt.String("default"); ok {
		switch v {
		case "allow":
			c.Bash.DefaultAllow = true
		case "deny":
			c.Bash.DefaultAllow = false
		default:
			return fmt.Errorf("[tools.bash]: default must be \"allow\" or \"deny\", got %q", v)
		}
	}
	if v, ok := bt.Int("timeout_secs"); ok {
		c.Bash.TimeoutSecs = int(v)
	}
	if v, ok := bt.Int("max_output_bytes"); ok {
		c.Bash.MaxOutputBytes = int(v)
	}

	dm := doc.Table("demo")
	if v, ok := dm.String("id"); ok {
		c.Demo.ID = v
	}
	if v, ok := dm.String("subject"); ok {
		c.Demo.Subject = v
	}
	if v, ok := dm.String("prompt"); ok {
		c.Demo.Prompt = v
	}
	if v, ok := dm.String("class"); ok {
		c.Demo.Class = v
	}

	kp := doc.Table("keyproxy")
	if v, ok := kp.String("url"); ok {
		c.KeyProxy.URL = v
	}
	if v, ok := kp.String("token_ref"); ok {
		c.KeyProxy.TokenRef = v
	}
	if v, ok := kp.Int("cache_ttl_secs"); ok {
		c.KeyProxy.CacheTTLSecs = int(v)
	}

	gt := doc.Table("gitea")
	if v, ok := gt.String("url"); ok {
		c.Gitea.URL = v
	}
	if v, ok := gt.String("key_ref"); ok {
		c.Gitea.KeyRef = v
	}
	if v, ok := gt.String("owner"); ok {
		c.Gitea.Owner = v
	}
	if v, ok := gt.String("repo"); ok {
		c.Gitea.Repo = v
	}
	if v, ok := gt.String("branch"); ok {
		c.Gitea.Branch = v
	}
	if v, ok := gt.Bool("commit_reports"); ok {
		c.Gitea.CommitReports = v
	}

	ev := doc.Table("events")
	if v, ok := ev.String("listen"); ok {
		c.Events.Listen = v
	}
	if v, ok := ev.String("state_dir"); ok {
		c.Events.StateDir = v
	}
	applyEventSource(&c.Events.Redmine, doc.Table("events", "redmine"))
	applyEventSource(&c.Events.Discourse, doc.Table("events", "discourse"))
	applyEventSource(&c.Events.Gitea, doc.Table("events", "gitea"))

	sv := doc.Table("serve")
	if v, ok := sv.String("listen"); ok {
		c.Serve.Listen = v
	}
	if v, ok := sv.String("vkey_ref"); ok {
		c.Serve.VKeyRef = v
	}
	if v, ok := sv.StringList("enabled_models"); ok {
		c.Serve.EnabledModels = v
	}

	qt := doc.Table("quota")
	if v, ok := qt.Bool("enabled"); ok {
		c.Quota.Enabled = v
	}
	if v, ok := qt.String("account"); ok {
		c.Quota.Account = v
	}
	if v, ok := qt.Float("plan_5h_credits"); ok {
		c.Quota.Plan5hCredits = v
	}
	if v, ok := qt.Float("plan_weekly_credits"); ok {
		c.Quota.PlanWeeklyCredits = v
	}
	if v, ok := qt.String("usage_url"); ok {
		c.Quota.UsageURL = v
	}
	if v, ok := qt.String("key_ref"); ok {
		c.Quota.KeyRef = v
	}
	if v, ok := qt.Int("poll_interval_secs"); ok {
		c.Quota.PollIntervalSecs = int(v)
	}
	if v, ok := qt.Float("defer_at_pct"); ok {
		c.Quota.DeferAtPct = v
	}
	if v, ok := qt.Float("block_at_pct"); ok {
		c.Quota.BlockAtPct = v
	}
	if v, ok := qt.String("peak_start"); ok {
		c.Quota.PeakStart = v
	}
	if v, ok := qt.String("peak_end"); ok {
		c.Quota.PeakEnd = v
	}
	if v, ok := qt.String("timezone"); ok {
		c.Quota.Timezone = v
	}
	if v, ok := qt.Bool("peak_weekdays_only"); ok {
		c.Quota.PeakWeekdaysOnly = v
	}
	if v, ok := qt.StringList("peak_classes"); ok {
		c.Quota.PeakClasses = v
	}
	if v, ok := qt.String("redis_url"); ok {
		c.Quota.RedisURL = v
	}

	rs := doc.Table("resources")
	if v, ok := rs.Bool("enabled"); ok {
		c.Resources.Enabled = v
	}
	if v, ok := rs.Float("max_load_avg"); ok {
		c.Resources.MaxLoadAvg = v
	}
	if v, ok := rs.Float("min_mem_available_mb"); ok {
		c.Resources.MinMemAvailableMB = v
	}
	if v, ok := rs.Float("min_disk_free_mb"); ok {
		c.Resources.MinDiskFreeMB = v
	}
	if v, ok := rs.Float("max_io_delay_pct"); ok {
		c.Resources.MaxIODelayPct = v
	}
	if v, ok := rs.String("proc_root"); ok {
		c.Resources.ProcRoot = v
	}
	if v, ok := rs.String("sys_root"); ok {
		c.Resources.SysRoot = v
	}
	return nil
}

func applyEventSource(dst *EventSourceConfig, src TOMLDoc) {
	if v, ok := src.String("secret_ref"); ok {
		dst.SecretRef = v
	}
	if v, ok := src.String("secret_header"); ok {
		dst.SecretHeader = v
	}
}

// Validate enforces the invariants the conductor relies on.
func (c *Config) Validate() error {
	if c.Vertical == "" {
		return fmt.Errorf("[core]: vertical is required")
	}
	if c.Loop.MaxRounds < 1 {
		return fmt.Errorf("[loop]: max_rounds must be >= 1")
	}
	if c.LiteLLM.BaseURL == "" {
		return fmt.Errorf("[litellm]: base_url is required")
	}
	if c.LiteLLM.KeyRef == "" {
		return fmt.Errorf("[litellm]: key_ref is required (env:NAME, file:PATH, or literal:VALUE)")
	}
	if err := CheckKeyRef(c.LiteLLM.KeyRef); err != nil {
		return fmt.Errorf("[litellm]: %w", err)
	}
	if c.LiteLLM.TimeoutSecs < 1 || c.LiteLLM.MaxRetries < 0 {
		return fmt.Errorf("[litellm]: bad timeout_secs/max_retries")
	}

	// Redmine is optional (demo-only configs); if any piece is set, the rest
	// of the minimum set must be too.
	rc := c.Redmine
	if rc.URL != "" || rc.KeyRef != "" || rc.ScopeQuery != "" || rc.ScopeQueryID != 0 {
		if rc.URL == "" {
			return fmt.Errorf("[redmine]: url is required when redmine is configured")
		}
		if rc.KeyRef == "" {
			return fmt.Errorf("[redmine]: key_ref is required when redmine is configured")
		}
		if err := CheckKeyRef(rc.KeyRef); err != nil {
			return fmt.Errorf("[redmine]: %w", err)
		}
		if rc.ScopeQuery == "" && rc.ScopeQueryID == 0 {
			return fmt.Errorf("[redmine]: scope_query or scope_query_id is required")
		}
	}

	if len(c.Models.Tiers) == 0 {
		return fmt.Errorf("[models]: at least one tier alias is required")
	}
	if _, ok := c.Models.Tiers[c.Models.DefaultTier]; !ok {
		return fmt.Errorf("[models]: default_tier %q has no entry in [models]", c.Models.DefaultTier)
	}
	for class, tier := range c.Models.Classes {
		if _, ok := c.Models.Tiers[tier]; !ok {
			return fmt.Errorf("[models.classes]: class %q points at unknown tier %q", class, tier)
		}
	}

	if c.Bash.TimeoutSecs < 1 || c.Bash.MaxOutputBytes < 1 {
		return fmt.Errorf("[tools.bash]: bad timeout_secs/max_output_bytes")
	}
	if c.Demo.Prompt == "" {
		return fmt.Errorf("[demo]: prompt is required")
	}

	// Events are optional (`once` configs need none); refs that ARE set must
	// be well-formed so the receiver fails at startup, not mid-webhook.
	for name, src := range map[string]EventSourceConfig{
		"redmine":   c.Events.Redmine,
		"discourse": c.Events.Discourse,
		"gitea":     c.Events.Gitea,
	} {
		if src.SecretRef == "" {
			continue
		}
		if err := CheckKeyRef(src.SecretRef); err != nil {
			return fmt.Errorf("[events.%s]: %w", name, err)
		}
	}
	if c.Events.Listen == "" || c.Events.StateDir == "" {
		return fmt.Errorf("[events]: listen and state_dir must not be empty")
	}

	// Serve is optional (`once`/`loop` configs need none); a vkey that IS
	// set must be well-formed, and enabled_models entries must name real
	// catalog models (mopac-<class>) so the front door fails at startup.
	if c.Serve.VKeyRef != "" {
		if err := CheckKeyRef(c.Serve.VKeyRef); err != nil {
			return fmt.Errorf("[serve]: %w", err)
		}
	}
	for _, m := range c.Serve.EnabledModels {
		class := strings.TrimPrefix(m, "mopac-")
		if !strings.HasPrefix(m, "mopac-") || class == "" || c.Models.Classes[class] == "" {
			return fmt.Errorf("[serve]: enabled_models entry %q is not servable (must be mopac-<class> from [models.classes])", m)
		}
	}
	if c.Serve.Listen == "" {
		return fmt.Errorf("[serve]: listen must not be empty")
	}

	if c.Loop.PollIntervalSecs < 1 {
		return fmt.Errorf("[loop]: poll_interval_secs must be >= 1")
	}
	if c.Loop.StateDir == "" {
		return fmt.Errorf("[loop]: state_dir must not be empty")
	}

	// Keyproxy is optional; if any piece is set, url + token_ref must be.
	if c.KeyProxy.URL != "" || c.KeyProxy.TokenRef != "" {
		if c.KeyProxy.URL == "" {
			return fmt.Errorf("[keyproxy]: url is required when keyproxy is configured")
		}
		if c.KeyProxy.TokenRef == "" {
			return fmt.Errorf("[keyproxy]: token_ref is required when keyproxy is configured (the bearer token for /v1/resolve)")
		}
		if err := CheckKeyRef(c.KeyProxy.TokenRef); err != nil {
			return fmt.Errorf("[keyproxy]: %w", err)
		}
		if strings.HasPrefix(c.KeyProxy.TokenRef, "mpk:") {
			return fmt.Errorf("[keyproxy]: token_ref must be a local ref (env:/file:/literal:), not mpk:")
		}
		if c.KeyProxy.CacheTTLSecs < 1 {
			return fmt.Errorf("[keyproxy]: bad cache_ttl_secs")
		}
	}

	// Gitea REPORT commit is optional; when on, the minimum set must be set.
	if c.Gitea.CommitReports {
		if c.Gitea.URL == "" || c.Gitea.KeyRef == "" || c.Gitea.Owner == "" || c.Gitea.Repo == "" {
			return fmt.Errorf("[gitea]: url, key_ref, owner and repo are required when commit_reports = true")
		}
		if err := CheckKeyRef(c.Gitea.KeyRef); err != nil {
			return fmt.Errorf("[gitea]: %w", err)
		}
	}

	// The quota gate is optional; when on, buckets, thresholds and the peak
	// window must be coherent so the gate never divides by zero or wraps
	// nonsense windows. usage_url without key_ref is an error (bearer-only).
	if c.Quota.Enabled {
		if c.Quota.Plan5hCredits <= 0 || c.Quota.PlanWeeklyCredits <= 0 {
			return fmt.Errorf("[quota]: plan_5h_credits and plan_weekly_credits must be > 0")
		}
		if c.Quota.PollIntervalSecs < 1 {
			return fmt.Errorf("[quota]: poll_interval_secs must be >= 1")
		}
		if !(c.Quota.DeferAtPct > 0 && c.Quota.DeferAtPct < 100) || !(c.Quota.BlockAtPct > 0 && c.Quota.BlockAtPct <= 100) {
			return fmt.Errorf("[quota]: defer_at_pct and block_at_pct must be in (0,100]")
		}
		if c.Quota.DeferAtPct > c.Quota.BlockAtPct {
			return fmt.Errorf("[quota]: defer_at_pct (%.0f) must be <= block_at_pct (%.0f)", c.Quota.DeferAtPct, c.Quota.BlockAtPct)
		}
		if _, err := ParseHHMM(c.Quota.PeakStart); err != nil {
			return fmt.Errorf("[quota]: peak_start: %w", err)
		}
		if _, err := ParseHHMM(c.Quota.PeakEnd); err != nil {
			return fmt.Errorf("[quota]: peak_end: %w", err)
		}
		if _, err := time.LoadLocation(c.Quota.Timezone); err != nil {
			return fmt.Errorf("[quota]: unknown timezone %q", c.Quota.Timezone)
		}
		if c.Quota.Account == "" {
			return fmt.Errorf("[quota]: account is required when the quota gate is enabled (shared-state bucket label)")
		}
		if c.Quota.UsageURL != "" && c.Quota.KeyRef == "" {
			return fmt.Errorf("[quota]: key_ref is required when usage_url is set (bearer auth)")
		}
		if c.Quota.KeyRef != "" {
			if err := CheckKeyRef(c.Quota.KeyRef); err != nil {
				return fmt.Errorf("[quota]: %w", err)
			}
		}
	}

	// The resource gate is optional; when on, thresholds must be sane.
	if c.Resources.Enabled {
		if c.Resources.MaxLoadAvg <= 0 || c.Resources.MinMemAvailableMB <= 0 || c.Resources.MinDiskFreeMB <= 0 {
			return fmt.Errorf("[resources]: thresholds must be > 0")
		}
		if !(c.Resources.MaxIODelayPct > 0 && c.Resources.MaxIODelayPct <= 100) {
			return fmt.Errorf("[resources]: max_io_delay_pct must be in (0,100]")
		}
	}
	return nil
}

// ParseHHMM parses a wall-clock time of day, "HH:MM" (24h).
func ParseHHMM(s string) (time.Duration, error) {
	parts := strings.Split(s, ":")
	if len(parts) != 2 || len(parts[0]) != 2 || len(parts[1]) != 2 {
		return 0, fmt.Errorf("want HH:MM, got %q", s)
	}
	h, err := strconv.Atoi(parts[0])
	if err != nil || h < 0 || h > 23 {
		return 0, fmt.Errorf("bad hour in %q", s)
	}
	m, err := strconv.Atoi(parts[1])
	if err != nil || m < 0 || m > 59 {
		return 0, fmt.Errorf("bad minute in %q", s)
	}
	return time.Duration(h)*time.Hour + time.Duration(m)*time.Minute, nil
}