package stacks

import (
	"fmt"
	"os"
	"path/filepath"
	"regexp"
	"sort"
	"strings"
	"time"

	"gitea.dooplex.hu/admin/felhom-controller/internal/util"
)

// ── The family gate (v0.287.0, `09` §3 decisions 63 and 64; R-780) ───────────────────────────────────────
//
// A PERMANENT gate in front of an app whose template says `family_gate: true`: only a member of the household's family
// list (internal/family — each with their OWN password) or the household itself (a dashboard session vouching) gets
// through. Same mechanism as the setup gate (decision 46): a traefik file-provider file puts a forwardAuth door in
// front of every router the app publishes; internal/web/family_gate.go answers it. Differences, each deliberate:
//
//   - it never opens: the file stays while the app is installed;
//   - its priority is BELOW the install hold, the setup gate and the sign-up block (each is stricter), ABOVE the app's
//     own docker routers;
//   - `family_gate_except:` lists path prefixes a phone or e-reader app calls (Grimmory's OPDS/Kobo/KOReader). Each
//     gets a router WITHOUT the door — the app's OWN login decides there. Every exception is ANCHORED at a path-segment
//     boundary (`^/prefix(/|$)`): traefik's PathPrefix is a plain string prefix, and the spike measured
//     `/api/v1/opdsx` walking past an unanchored `/api/v1/opds` (finding F1, audits/permanent-gate-2026-10-01/).
//
// The record (`family_gate:` in app.yaml) is written at install (and at the restore of a removed app — the R-773
// lesson), so a catalog change never gates or un-gates an installed app; the exceptions follow the current template.
// Pinned by internal/stacks/family_gate_test.go.

const (
	familyGateAuthURL  = "http://felhom-controller:8080/__felhom_gate/family"
	familyGatePriority = 40000 // < setupGatePriority (100000): the setup gate, sign-up block, install hold outrank it
	familyExceptBoost  = 20000 // an exception router outranks the family door, never the setup gate
)

// FamilyGateRecord is the app's family gate: on since its install. A life record (carried across a restore).
type FamilyGateRecord struct {
	Since string   `yaml:"since" json:"since"`
	Hosts []string `yaml:"hosts,omitempty" json:"hosts,omitempty"`
}

// exceptPathRE: a literal path prefix — no traefik matcher, no regex. Anything else is refused, never escaped into
// something it did not say.
var exceptPathRE = regexp.MustCompile(`^/[A-Za-z0-9._~/-]*$`)

// FamilyExceptRegexp turns one exception prefix into the anchored regexp the router uses: the prefix itself, or the
// prefix followed by "/". A trailing "/" in the template is the same prefix.
func FamilyExceptRegexp(p string) (string, error) {
	if !exceptPathRE.MatchString(p) || strings.Contains(p, "//") || strings.Contains(p, "/../") || strings.HasSuffix(p, "/..") {
		return "", fmt.Errorf("family_gate_except %q: a literal path prefix starting with /", p)
	}
	p = strings.TrimRight(p, "/")
	if p == "" {
		return "", fmt.Errorf("family_gate_except %q would except the whole app", "/")
	}
	return "^" + regexp.QuoteMeta(p) + "(/|$)", nil
}

func renderFamilyGate(name string, rs []gateRouter, except []string) (string, error) {
	var res []string
	for _, p := range except {
		re, err := FamilyExceptRegexp(p)
		if err != nil {
			return "", err
		}
		res = append(res, re)
	}
	var b strings.Builder
	mw := "felhom-family-gate-" + name
	fmt.Fprintf(&b, "# Family gate for %s — managed by felhom-controller (`09` §3 decisions 63-64).\n", name)
	b.WriteString("# Only the household's family members (and the household) reach the app; the listed paths keep the app's own login.\n")
	b.WriteString("http:\n  middlewares:\n")
	fmt.Fprintf(&b, "    %s:\n      forwardAuth:\n        address: %q\n", mw, familyGateAuthURL)
	b.WriteString("  routers:\n")
	tls := func(r gateRouter) {
		if r.CertResolver != "" {
			fmt.Fprintf(&b, "      tls:\n        certResolver: %s\n", r.CertResolver)
		} else {
			b.WriteString("      tls: {}\n")
		}
	}
	for _, r := range rs {
		fmt.Fprintf(&b, "    %s-%s:\n", mw, r.Name)
		fmt.Fprintf(&b, "      rule: %q\n", r.Rule)
		fmt.Fprintf(&b, "      priority: %d\n", familyGatePriority+len(r.Rule))
		b.WriteString("      entryPoints:\n        - websecure\n")
		tls(r)
		fmt.Fprintf(&b, "      middlewares:\n        - %s@file\n", mw)
		fmt.Fprintf(&b, "      service: %q\n", r.Service+"@docker")
		for i, re := range res {
			rule := fmt.Sprintf("(%s) && PathRegexp(`%s`)", r.Rule, re)
			fmt.Fprintf(&b, "    %s-%s-except-%d:\n", mw, r.Name, i)
			fmt.Fprintf(&b, "      rule: %q\n", rule)
			fmt.Fprintf(&b, "      priority: %d\n", familyGatePriority+familyExceptBoost+len(rule))
			b.WriteString("      entryPoints:\n        - websecure\n")
			tls(r)
			fmt.Fprintf(&b, "      service: %q\n", r.Service+"@docker")
		}
	}
	return b.String(), nil
}

func (m *Manager) familyGatePath(name string) string {
	return filepath.Join(m.setupGateDir(), "family-gate-"+name+".yml")
}

// writeFamilyGate writes (or refreshes) the app's family-gate file. Returns the hosts it covers.
func (m *Manager) writeFamilyGate(name, composePath string, env map[string]string, except []string) ([]string, error) {
	rs, err := gateRoutersFromCompose(composePath, env)
	if err != nil {
		return nil, err
	}
	want, err := renderFamilyGate(name, rs, except)
	if err != nil {
		return nil, err
	}
	if err := os.MkdirAll(m.setupGateDir(), 0o755); err != nil {
		return nil, err
	}
	p := m.familyGatePath(name)
	if cur, err := os.ReadFile(p); err == nil && string(cur) == want {
		return gateHosts(rs), nil
	}
	tmp := p + ".tmp"
	if err := os.WriteFile(tmp, []byte(want), 0o644); err != nil {
		return nil, err
	}
	if err := os.Rename(tmp, p); err != nil {
		return nil, err
	}
	return gateHosts(rs), nil
}

// prepareFamilyGate is the install's (and a removed app's restore's) step: the file BEFORE the first start, then the
// record the caller saves. Cannot write it → the caller refuses: a family app is never published open.
func (m *Manager) prepareFamilyGate(name, composePath string, env map[string]string, meta *Metadata) (*FamilyGateRecord, error) {
	hosts, err := m.writeFamilyGate(name, composePath, env, meta.FamilyGateExcept)
	if err != nil {
		return nil, err
	}
	m.logger.Printf("[INFO] [stacks] %s: family gate ON before the first start — only family members reach %v (exceptions: %v)", name, hosts, meta.FamilyGateExcept)
	return &FamilyGateRecord{Since: m.now().UTC().Format(time.RFC3339), Hosts: hosts}, nil
}

// FamilyGateHost maps a host to the family-gated app that owns it.
func (m *Manager) FamilyGateHost(host string) (name string, found bool) {
	host = strings.ToLower(host)
	m.mu.RLock()
	defer m.mu.RUnlock()
	for n, st := range m.stacks {
		if st.Deployed && st.AppConfig != nil && st.AppConfig.FamilyGate != nil && containsStr(st.AppConfig.FamilyGate.Hosts, host) {
			return n, true
		}
	}
	return "", false
}

// familyGateTick: every installed family app has its file (rewritten from the current template's exceptions); every
// other family-gate file goes.
func (m *Manager) familyGateTick() {
	type item struct {
		name, dir, compose string
		except             []string
	}
	var items []item
	keep := map[string]bool{}
	m.mu.RLock()
	for n, st := range m.stacks {
		if !st.Deployed || st.AppConfig == nil || st.AppConfig.FamilyGate == nil {
			continue
		}
		items = append(items, item{name: n, dir: filepath.Dir(st.ComposePath), compose: st.ComposePath,
			except: append([]string(nil), st.Meta.FamilyGateExcept...)})
		keep[n] = true
	}
	m.mu.RUnlock()
	if ents, err := os.ReadDir(m.setupGateDir()); err == nil {
		for _, e := range ents {
			n := e.Name()
			if !strings.HasPrefix(n, "family-gate-") || !strings.HasSuffix(n, ".yml") {
				continue
			}
			app := strings.TrimSuffix(strings.TrimPrefix(n, "family-gate-"), ".yml")
			if !keep[app] {
				if err := os.Remove(m.familyGatePath(app)); err == nil {
					m.logger.Printf("[INFO] [stacks] %s: removed the family-gate file of an app that is not installed", app)
				}
			}
		}
	}
	sort.Slice(items, func(i, j int) bool { return items[i].name < items[j].name })
	for _, it := range items {
		cfg := LoadAppConfigDecrypted(it.dir, m.encKey)
		if cfg == nil {
			continue
		}
		if _, err := m.writeFamilyGate(it.name, it.compose, cfg.Env, it.except); err != nil {
			m.logger.Printf("[ERROR] [stacks] %s: the family gate's traefik file could not be (re)written: %v", it.name, err)
		}
	}
}

// ── the template's minimum controller (v0.287.0) ─────────────────────────────────────────────────────────

var controllerVersion string

// SetControllerVersion tells the stacks package which controller it runs in (main.go). Empty = unknown (a dev build):
// min_controller is then not enforced, and that is logged.
func SetControllerVersion(v string) { controllerVersion = v }

// ErrNeedsNewerController: the template needs a newer controller than this one.
var ErrNeedsNewerController = fmt.Errorf("the app needs a newer box software")

// checkMinController refuses a template whose `min_controller` is above this controller. A family-gated app on a
// controller that does not know the field would be installed OPEN — this is the field a NEWER template uses to say so.
func checkMinController(meta *Metadata) error {
	if strings.TrimSpace(meta.MinController) == "" {
		return nil
	}
	need, err := util.ParseVersion(meta.MinController)
	if err != nil {
		return fmt.Errorf("min_controller %q unreadable: %w", meta.MinController, err)
	}
	have, err := util.ParseVersion(controllerVersion)
	if err != nil {
		return nil // a dev build: no version to compare (logged at the caller)
	}
	if have.Compare(need) < 0 {
		return fmt.Errorf("%w (needs %s, this box runs %s)", ErrNeedsNewerController, need, have)
	}
	return nil
}