package config

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

// ProfileName is the set of legal values for a Run's profile column.
// Exposed as constants so callers (UI handler, tests, agent) don't
// sprinkle literal strings.
const (
	ProfileQuick = "quick"
	ProfileDeep  = "deep"
	ProfileSoak  = "soak"
)

// AllProfiles is the canonical ordering shown in the picker. Leftmost
// is the default; rightmost is the longest-running.
var AllProfiles = []string{ProfileQuick, ProfileDeep, ProfileSoak}

// IsValidProfile returns true when name is one of the known profile
// identifiers. Used at the UI boundary to reject malformed POSTs and in
// store code as a fallback guard.
func IsValidProfile(name string) bool {
	for _, p := range AllProfiles {
		if p == name {
			return true
		}
	}
	return false
}

// Vetting holds the stage order + threshold defaults that are shared
// across all profiles. Only the per-stage durations/concurrency differ
// between quick/deep/soak; gates like "CPU > 92C fails the run" apply
// to a 2-minute quick run and a 12-hour soak alike.
type Vetting struct {
	Stages     []string            `yaml:"stages"`
	Thresholds []ThresholdDefaults `yaml:"thresholds"`
}

// ThresholdDefaults is the YAML shape of a threshold declaration. One
// stanza can declare a per-stage rule ("stage: Network") or a global
// rule ("stage: *") — the threshold evaluator applies both to samples
// with matching (stage, kind, key).
type ThresholdDefaults struct {
	Stage    string  `yaml:"stage"`
	Kind     string  `yaml:"kind"`
	Key      string  `yaml:"key"`
	Op       string  `yaml:"op"`       // lt|lte|gt|gte|within_pct
	Value    float64 `yaml:"value"`
	Nominal  float64 `yaml:"nominal"`  // only used by within_pct (e.g. 12.0 for +12V rail)
	Unit     string  `yaml:"unit"`
	Severity string  `yaml:"severity"` // critical|warning
}

// ProfileRegistry is the in-memory view of the `profiles:` block in
// vetting.yaml. The orchestrator queries it at run creation time to
// seed thresholds and (in Phase 3+) to scale per-stage durations.
type ProfileRegistry struct {
	// Shared stage ordering + threshold defaults. Every profile walks
	// the same list; only durations/concurrency differ.
	Vetting Vetting

	// Profiles is keyed by name ("quick"/"deep"/"soak"). Inherit is
	// already resolved at load time — a caller sees a flattened view.
	Profiles map[string]Profile
}

// Profile is a loaded profile. StageTimeouts is keyed by stage name.
// Defaults carries the free-form knobs each probe reads.
type Profile struct {
	Name          string
	Inherit       string
	StageTimeouts map[string]time.Duration
	Defaults      map[string]map[string]any
}

// StageConfig is the flat view of a profile's knobs, shipped on the
// claim response so the agent can size CPUStress/Storage/Network/Burn
// work without parsing YAML. Empty values mean "fall back to the
// agent's compile-time default" — an older orchestrator that doesn't
// set these fields keeps working unchanged.
type StageConfig struct {
	Profile       string            `json:"profile"`
	StageTimeouts map[string]string `json:"stage_timeouts,omitempty"`
	CPUStress     CPUStressKnobs    `json:"cpustress"`
	Storage       StorageKnobs      `json:"storage"`
	Network       NetworkKnobs      `json:"network"`
	Burn          BurnKnobs         `json:"burn"`
}

// CPUStressKnobs parallels the `cpustress:` block under `profiles.<name>.defaults`.
// Durations are YAML duration strings ("2m", "60m", "12h").
type CPUStressKnobs struct {
	CPUPass  string `json:"cpu_pass,omitempty"`
	MemPass  string `json:"mem_pass,omitempty"`
	EDACPoll string `json:"edac_poll,omitempty"`
}

// StorageKnobs parallels `storage:` defaults. Mode is "fio_sample" (quick)
// or "full_disk" (deep/soak). Verify names the integrity mode ("md5" or "").
type StorageKnobs struct {
	Mode    string `json:"mode,omitempty"`
	FioSize string `json:"fio_size,omitempty"`
	FioTime string `json:"fio_time,omitempty"`
	FioBS   string `json:"fio_bs,omitempty"`
	FioRW   string `json:"fio_rw,omitempty"`
	Verify  string `json:"verify,omitempty"`
}

// NetworkKnobs parallels `network:` defaults. Duration is a YAML string.
type NetworkKnobs struct {
	Duration string `json:"duration,omitempty"`
}

// BurnKnobs parallels `burn:` defaults. Duration is the total Burn window.
// CPUWorkers is "all" (agent picks runtime.NumCPU) or a numeric string.
// MemPct is a percentage of MemAvailable to stress. FioOnSpare gates
// whether fio runs inside Burn (set false if operator lacks a spare
// partition). IperfParallel is the parallel stream count fed to iperf3 -P.
type BurnKnobs struct {
	Duration      string `json:"duration,omitempty"`
	CPUWorkers    string `json:"cpu_workers,omitempty"`
	MemPct        int    `json:"mem_pct,omitempty"`
	FioOnSpare    bool   `json:"fio_on_spare,omitempty"`
	IperfParallel int    `json:"iperf_parallel,omitempty"`
}

// ResolveStageConfig flattens the named profile into the wire shape the
// claim handler ships. Missing keys render as empty strings so the agent
// falls back to its own defaults.
func (pr *ProfileRegistry) ResolveStageConfig(name string) StageConfig {
	if pr == nil {
		return StageConfig{Profile: name}
	}
	p, err := pr.Lookup(name)
	if err != nil {
		return StageConfig{Profile: name}
	}
	out := StageConfig{Profile: p.Name}
	if len(p.StageTimeouts) > 0 {
		out.StageTimeouts = make(map[string]string, len(p.StageTimeouts))
		for k, v := range p.StageTimeouts {
			out.StageTimeouts[k] = v.String()
		}
	}
	cpu := p.Defaults["cpustress"]
	out.CPUStress.CPUPass = yamlString(cpu, "cpu_pass")
	out.CPUStress.MemPass = yamlString(cpu, "mem_pass")
	out.CPUStress.EDACPoll = yamlString(cpu, "edac_poll")
	st := p.Defaults["storage"]
	out.Storage.Mode = yamlString(st, "mode")
	out.Storage.FioSize = yamlString(st, "fio_size")
	out.Storage.FioTime = yamlString(st, "fio_time")
	out.Storage.FioBS = yamlString(st, "fio_bs")
	out.Storage.FioRW = yamlString(st, "fio_rw")
	out.Storage.Verify = yamlString(st, "verify")
	net := p.Defaults["network"]
	out.Network.Duration = yamlString(net, "duration")
	burn := p.Defaults["burn"]
	out.Burn.Duration = yamlString(burn, "duration")
	out.Burn.CPUWorkers = yamlString(burn, "cpu_workers")
	out.Burn.MemPct = yamlInt(burn, "mem_pct")
	out.Burn.FioOnSpare = yamlBool(burn, "fio_on_spare")
	out.Burn.IperfParallel = yamlInt(burn, "iperf_parallel")
	return out
}

// yamlInt coerces a map[string]any entry to int. Accepts native int,
// float64 (JSON numbers round-trip as float), or numeric string. Missing
// / malformed values return 0 so the agent falls back to its default.
func yamlInt(m map[string]any, key string) int {
	v, ok := m[key]
	if !ok || v == nil {
		return 0
	}
	switch x := v.(type) {
	case int:
		return x
	case int64:
		return int(x)
	case float64:
		return int(x)
	case string:
		// Best-effort string → int. Empty and non-numeric fall through
		// to zero.
		var n int
		if _, err := fmt.Sscanf(x, "%d", &n); err == nil {
			return n
		}
	}
	return 0
}

// yamlBool accepts native bool or "true"/"false" strings. Anything else
// (missing key, numeric, typo) returns false — a safer default than
// "true" for a destructive knob like fio_on_spare.
func yamlBool(m map[string]any, key string) bool {
	v, ok := m[key]
	if !ok || v == nil {
		return false
	}
	switch x := v.(type) {
	case bool:
		return x
	case string:
		return strings.EqualFold(x, "true")
	}
	return false
}

// yamlString coerces a map[string]any entry to its string form. YAML
// durations like "2m" parse as strings; numeric literals like 5 parse as
// int. We format non-string scalars with fmt.Sprint so the agent can
// still interpret them.
func yamlString(m map[string]any, key string) string {
	v, ok := m[key]
	if !ok || v == nil {
		return ""
	}
	if s, ok := v.(string); ok {
		return s
	}
	return fmt.Sprint(v)
}

// Lookup returns the profile with the given name. Falls back to the
// default profile (quick) if the name is empty. Returns an error when
// the name is non-empty but unknown so the caller can surface it.
func (pr *ProfileRegistry) Lookup(name string) (Profile, error) {
	if name == "" {
		name = ProfileQuick
	}
	p, ok := pr.Profiles[name]
	if !ok {
		return Profile{}, fmt.Errorf("unknown profile %q", name)
	}
	return p, nil
}

// Names returns the registry's profile names in the canonical
// picker order (quick/deep/soak). Profiles present in the config but
// unknown to AllProfiles are appended after, alphabetically.
func (pr *ProfileRegistry) Names() []string {
	out := make([]string, 0, len(pr.Profiles))
	seen := map[string]bool{}
	for _, n := range AllProfiles {
		if _, ok := pr.Profiles[n]; ok {
			out = append(out, n)
			seen[n] = true
		}
	}
	for n := range pr.Profiles {
		if !seen[n] {
			out = append(out, n)
		}
	}
	return out
}

// Stages returns the shared stage order, or a safe default when the
// config didn't declare one — keeps tests that don't build a full
// ProfileRegistry from tripping over a nil slice.
func (pr *ProfileRegistry) Stages() []string {
	if len(pr.Vetting.Stages) == 0 {
		return DefaultStages()
	}
	out := make([]string, len(pr.Vetting.Stages))
	copy(out, pr.Vetting.Stages)
	return out
}

// DefaultStages is the canonical stage list the orchestrator walks
// when no config is loaded. Mirrored in the vetting.yaml shipped with
// the repo so edits to the slice and the file stay in sync.
func DefaultStages() []string {
	return []string{
		"Inventory",
		"Firmware",
		"SpecValidate",
		"SMART",
		"CPUStress",
		"Storage",
		"Network",
		"Burn",
		"GPU",
		"PSU",
		"Reporting",
	}
}

// rawProfile is the YAML shape before inherit resolution. Durations
// arrive as strings (e.g. "2h") so we can parse them with
// time.ParseDuration instead of rolling our own.
type rawProfile struct {
	Inherit       string                       `yaml:"inherit"`
	StageTimeouts map[string]string            `yaml:"stage_timeouts"`
	Defaults      map[string]map[string]any    `yaml:"defaults"`
}

type rawProfilesBlock struct {
	Vetting  Vetting               `yaml:"vetting"`
	Profiles map[string]rawProfile `yaml:"profiles"`
}

// buildProfileRegistry flattens a rawProfilesBlock into a ProfileRegistry.
// Resolves `inherit:` by recursive merge (child keys win), parses
// stage_timeouts strings into time.Durations, and returns an error if
// the inherit chain loops or references an unknown profile.
func buildProfileRegistry(raw rawProfilesBlock) (*ProfileRegistry, error) {
	if len(raw.Profiles) == 0 {
		raw.Profiles = defaultRawProfiles()
	}
	out := &ProfileRegistry{
		Vetting:  raw.Vetting,
		Profiles: make(map[string]Profile, len(raw.Profiles)),
	}
	if len(out.Vetting.Stages) == 0 {
		out.Vetting.Stages = DefaultStages()
	}
	for name := range raw.Profiles {
		resolved, err := resolveProfile(raw.Profiles, name, nil)
		if err != nil {
			return nil, err
		}
		out.Profiles[name] = resolved
	}
	return out, nil
}

// resolveProfile recursively walks inherit chains, depth-first. The
// visited slice is a cycle guard — we add the current name before
// recursing and bail if we ever see it again.
func resolveProfile(all map[string]rawProfile, name string, visited []string) (Profile, error) {
	for _, v := range visited {
		if v == name {
			return Profile{}, fmt.Errorf("profile inherit cycle: %s -> %s", strings.Join(visited, " -> "), name)
		}
	}
	raw, ok := all[name]
	if !ok {
		return Profile{}, fmt.Errorf("unknown profile %q", name)
	}
	base := Profile{
		Name:          name,
		Inherit:       raw.Inherit,
		StageTimeouts: map[string]time.Duration{},
		Defaults:      map[string]map[string]any{},
	}
	if raw.Inherit != "" {
		parent, err := resolveProfile(all, raw.Inherit, append(visited, name))
		if err != nil {
			return Profile{}, err
		}
		for k, v := range parent.StageTimeouts {
			base.StageTimeouts[k] = v
		}
		for k, v := range parent.Defaults {
			copyMap := make(map[string]any, len(v))
			for kk, vv := range v {
				copyMap[kk] = vv
			}
			base.Defaults[k] = copyMap
		}
	}
	for stage, s := range raw.StageTimeouts {
		d, err := time.ParseDuration(s)
		if err != nil {
			return Profile{}, fmt.Errorf("profile %s stage_timeouts[%s]: %w", name, stage, err)
		}
		base.StageTimeouts[stage] = d
	}
	for group, kv := range raw.Defaults {
		dest, ok := base.Defaults[group]
		if !ok {
			dest = map[string]any{}
			base.Defaults[group] = dest
		}
		for k, v := range kv {
			dest[k] = v
		}
	}
	return base, nil
}

// defaultRawProfiles returns sane per-profile durations + probe knobs
// used when vetting.yaml omits the `profiles:` block entirely. Matches
// the plan's per-stage budget table so the agent still gets coherent
// CPUStress/Storage/Network knobs without any operator-visible config.
func defaultRawProfiles() map[string]rawProfile {
	return map[string]rawProfile{
		ProfileQuick: {
			StageTimeouts: map[string]string{
				"CPUStress": "5m",
				"Storage":   "5m",
				"Network":   "2m",
				"Burn":      "3m",
				"PSU":       "1m",
			},
			Defaults: map[string]map[string]any{
				"cpustress": {"cpu_pass": "2m", "mem_pass": "2m", "edac_poll": "10s"},
				"storage":   {"mode": "fio_sample", "fio_size": "1GiB", "fio_time": "3m", "fio_bs": "4k", "fio_rw": "randrw", "verify": "md5"},
				"network":   {"duration": "60s"},
				"burn":      {"duration": "2m", "cpu_workers": "all", "mem_pct": 50, "fio_on_spare": true, "iperf_parallel": 2},
			},
		},
		ProfileDeep: {
			StageTimeouts: map[string]string{
				"CPUStress": "2h",
				"Storage":   "4h",
				"Network":   "35m",
				"Burn":      "3h",
				"PSU":       "10m",
			},
			Defaults: map[string]map[string]any{
				"cpustress": {"cpu_pass": "60m", "mem_pass": "60m", "edac_poll": "10s"},
				"storage":   {"mode": "full_disk", "fio_time": "2h", "fio_bs": "4k", "fio_rw": "randrw", "verify": "md5"},
				"network":   {"duration": "30m"},
				"burn":      {"duration": "2h", "cpu_workers": "all", "mem_pct": 70, "fio_on_spare": true, "iperf_parallel": 4},
			},
		},
		ProfileSoak: {
			Inherit: ProfileDeep,
			StageTimeouts: map[string]string{
				"CPUStress": "14h",
				"Storage":   "8h",
				"Network":   "2h30m",
				"Burn":      "20h",
				"PSU":       "15m",
			},
			Defaults: map[string]map[string]any{
				"cpustress": {"cpu_pass": "12h"},
				"storage":   {"mode": "full_disk", "fio_time": "6h"},
				"network":   {"duration": "2h"},
				"burn":      {"duration": "18h", "iperf_parallel": 8},
			},
		},
	}
}