package stacks

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

// ── after_setup: the app's OWN sign-up switch, set once the first admin exists (v0.282.0, `09` §3 decisions 47, 49) ──
//
// Decision 47 closes open sign-up once an app's first admin exists. v0.281.0 did it with an address block only
// (signup_block.go). Measured 2026-09-29 evening: 9 of the 11 apps with a block also have their own switch, and every
// one is read from the environment at start (gitea through its env-to-ini; the others directly). So the template
// wires that switch to SIGNUP_CLOSED / SIGNUP_OPEN, whose compose default is OPEN — an installed app is unchanged by
// the catalog — and declares:
//
//	after_setup:
//	  env: {SIGNUP_CLOSED: "true"}      # merged into the app's env, then ONE `compose up -d`
//
// It runs when the setup gate opens (probe or the household's press) and on the household's "close sign-up now"
// (decision 49), AFTER the address block is up. The block stays either way: two locks. A failed step is recorded
// (`after_setup:` in app.yaml) and shown on the app page; the block still holds.
//
// The household's 15-minute window lifts BOTH: the env keys are removed (the compose default is open again) and the
// app is started once more; when the window ends the loop puts them back (one more start). The page says the app
// restarts.
//
// A command form (`service`, `command`, `success`, `env` names) follows after_install's argv-safe rules (R-713).
// Pinned by internal/stacks/after_setup_test.go.

// AfterSetupSpec is `.felhom.yml`'s `after_setup:`.
type AfterSetupSpec struct {
	Env     map[string]string `yaml:"env,omitempty" json:"env,omitempty"`
	Service string            `yaml:"service,omitempty" json:"service,omitempty"`
	User    string            `yaml:"user,omitempty" json:"user,omitempty"`
	Args    []string          `yaml:"args_env,omitempty" json:"args_env,omitempty"` // deploy values a command may use
	Command []string          `yaml:"command,omitempty" json:"command,omitempty"`
	Success string            `yaml:"success,omitempty" json:"success,omitempty"`
}

// Native-lock states in SetupGateRecord.NativeLock.
const (
	NativeLockApplied = "applied" // the app's own switch says closed
	NativeLockLifted  = "lifted"  // the household's window: the switch is open again
)

// afterSetupUp starts the app from its stored app.yaml (a seam: tests never reach Docker).
func (m *Manager) afterSetupUp(name string) error {
	if m.afterSetupUpFn != nil {
		return m.afterSetupUpFn(name)
	}
	return m.upFromAppConfig(name)
}

// setNativeEnv merges (lock) or removes (lift) the after_setup env keys in app.yaml.
func (m *Manager) setNativeEnv(name, dir string, spec *AfterSetupSpec, lock bool) bool {
	changed := false
	m.mutateAppConfig(name, dir, "after_setup_env", func(cfg *AppConfig) bool {
		if cfg.Env == nil {
			cfg.Env = map[string]string{}
		}
		for k, v := range spec.Env {
			if lock {
				if cfg.Env[k] != v {
					cfg.Env[k] = v
					changed = true
				}
			} else if _, ok := cfg.Env[k]; ok {
				delete(cfg.Env, k)
				changed = true
			}
		}
		return changed
	})
	return changed
}

// applyNativeLock sets (lock=true) or lifts the app's own switch, then starts the app once when anything changed.
// Records the outcome. Safe to call again: an unchanged env starts nothing.
func (m *Manager) applyNativeLock(name string, lock bool, why string) error {
	st, ok := m.GetStack(name)
	if !ok || st.Meta.AfterSetup == nil {
		return nil
	}
	spec := st.Meta.AfterSetup
	dir := filepath.Dir(st.ComposePath)
	record := func(ok bool, detail string) {
		rec := &AfterInstallRecord{At: m.now().UTC().Format(time.RFC3339), OK: ok, Detail: truncateStr(detail, 300)}
		state := NativeLockApplied
		if !lock {
			state = NativeLockLifted
		}
		m.mutateAppConfig(name, dir, "after_setup", func(cfg *AppConfig) bool {
			cfg.AfterSetup = rec
			if ok && cfg.SetupGate != nil {
				cfg.SetupGate.NativeLock = state
			}
			return true
		})
	}
	var err error
	// The switch works only if the app's INSTALLED compose reads the variable. An app installed before the template
	// wired it (decision 49's apps) carries the old compose until its next update: say so, never report a lock that
	// is not there. The address block still holds.
	if len(spec.Env) > 0 && lock {
		if miss := composeMissingVars(st.ComposePath, spec.Env); len(miss) > 0 {
			err = fmt.Errorf("the installed version of the app does not read %v yet — its own switch applies after its next update", miss)
			m.logger.Printf("[WARN] [stacks] %s: %v", name, err)
			record(false, err.Error())
			return err
		}
	}
	if len(spec.Env) > 0 {
		if m.setNativeEnv(name, dir, spec, lock) {
			err = m.afterSetupUp(name)
		}
	}
	if err == nil && lock && len(spec.Command) > 0 {
		err = m.runAfterSetupCommand(name, dir, spec)
	}
	if err != nil {
		m.logger.Printf("[ERROR] [stacks] %s: the app's own sign-up switch could not be %s (%s): %v — the address block still holds", name, map[bool]string{true: "closed", false: "opened"}[lock], why, err)
		record(false, err.Error())
		return err
	}
	keys := make([]string, 0, len(spec.Env))
	for k := range spec.Env {
		keys = append(keys, k)
	}
	sort.Strings(keys)
	m.logger.Printf("[INFO] [stacks] %s: the app's own sign-up switch %s (%s; env %v)", name, map[bool]string{true: "CLOSED", false: "opened for the household's window"}[lock], why, keys)
	record(true, "")
	return nil
}

// runAfterSetupCommand runs the command form once, with after_install's argv-safe expansion and success marker.
func (m *Manager) runAfterSetupCommand(name, dir string, spec *AfterSetupSpec) error {
	if spec.Service == "" || spec.Success == "" {
		return fmt.Errorf("after_setup command needs a service and a success marker")
	}
	cfg := LoadAppConfigDecrypted(dir, m.encKey)
	if cfg == nil {
		return fmt.Errorf("app.yaml unreadable")
	}
	cmd, err := expandAfterInstall(spec.Command, spec.Args, cfg.Env)
	if err != nil {
		return err
	}
	args := []string{"exec", "-T"}
	if spec.User != "" {
		args = append(args, "-u", spec.User)
	}
	args = append(args, spec.Service)
	args = append(args, cmd...)
	out, err := m.runInService(dir, args...)
	if err != nil || !strings.Contains(out, spec.Success) {
		return fmt.Errorf("after_setup command did not report %q (err %v)", spec.Success, err)
	}
	return nil
}

// runInService is the compose exec seam shared with after_install (afterLoadFn in tests).
func (m *Manager) runInService(dir string, args ...string) (string, error) {
	if m.afterLoadFn != nil {
		return m.afterLoadFn(dir, args...)
	}
	return m.composeExecCustomEnv(dir, m.stackEnv(dir), args...)
}

// ── "Close sign-up now" (decision 49) ─────────────────────────────────────────────────────────────────

// ErrCloseSignupNotOffered: the app is not installed, has no gate-free install, or its template has no lock.
var ErrCloseSignupNotOffered = fmt.Errorf("close sign-up is not offered for this app")

// CloseSignupOffered: an installed app whose template has a sign-up lock and whose install has none — an app
// installed before decision 47 (demo-hp's adventurelog, opengist). Offered once: the press records a lock.
func (m *Manager) CloseSignupOffered(name string) bool {
	st, ok := m.GetStack(name)
	if !ok || !st.Deployed || st.AppConfig == nil || st.AppConfig.SetupGate != nil {
		return false
	}
	return strings.TrimSpace(st.Meta.SignupBlock) != "" || st.Meta.AfterSetup != nil
}

// CloseSignupNow applies to an installed app exactly what a fresh install gets after its setup: a lock record
// (never a closed gate), the address block, then the app's own switch. It never gates the app and never touches
// its data.
func (m *Manager) CloseSignupNow(name string) error {
	if !m.CloseSignupOffered(name) {
		return ErrCloseSignupNotOffered
	}
	st, _ := m.GetStack(name)
	dir := filepath.Dir(st.ComposePath)
	cfg := LoadAppConfigDecrypted(dir, m.encKey)
	if cfg == nil {
		return fmt.Errorf("%s: app.yaml unreadable", name)
	}
	rs, err := gateRoutersFromCompose(st.ComposePath, cfg.Env)
	if err != nil {
		return fmt.Errorf("%s: the app's addresses could not be read: %w", name, err)
	}
	hosts := gateHosts(rs)
	if b := strings.TrimSpace(st.Meta.SignupBlock); b != "" {
		if err := m.writeSignupBlock(name, hosts, b); err != nil {
			return fmt.Errorf("%s: the sign-up block could not be written: %w", name, err)
		}
	}
	now := m.now().UTC().Format(time.RFC3339)
	done := false
	m.mutateAppConfig(name, dir, "setup_gate", func(c *AppConfig) bool {
		if c.SetupGate != nil {
			return false
		}
		c.SetupGate = &SetupGateRecord{State: SetupGateOpen, Since: now, Hosts: hosts, OpenedAt: now, OpenedBy: SetupGateByCloseSignup}
		done = true
		return true
	})
	if !done {
		_ = m.removeSignupBlockFile(name)
		return fmt.Errorf("%s: the lock could not be recorded", name)
	}
	m.logger.Printf("[INFO] [stacks] %s: the household closed sign-up on an app installed before decision 47 (hosts %v)", name, hosts)
	if st.Meta.AfterSetup != nil {
		m.goNativeLock(name, true, "close sign-up now")
	}
	return nil
}

// restoreSignupLock is R-773's half of PersistUnitRedeployConfig: for an app whose template locks sign-up, the lock
// record (opened_by "restore", never a closed gate) and — best effort — its block file. nil, nil when the template has
// no lock. A block that cannot be written now is logged and left to the loop (the record says it is wanted); hosts that
// cannot be read refuse the restore before anything starts (fail closed, as the gate's own install does).
// The app's own switch (`after_setup`) is the loop's: NativeLock is "" so it runs once the app is up.
func (m *Manager) restoreSignupLock(name, composePath string, env map[string]string, meta *Metadata) (*SetupGateRecord, error) {
	block := strings.TrimSpace(meta.SignupBlock)
	if block == "" && meta.AfterSetup == nil {
		return nil, nil
	}
	rs, err := gateRoutersFromCompose(composePath, env)
	if err != nil {
		return nil, fmt.Errorf("%s: the app's addresses could not be read: %w", name, err)
	}
	hosts := gateHosts(rs)
	if block != "" {
		if err := m.writeSignupBlock(name, hosts, block); err != nil {
			m.logger.Printf("[ERROR] [stacks] %s: the restore's sign-up block could not be written: %v — the loop retries; sign-up is OPEN until it is", name, err)
		}
	}
	now := m.now().UTC().Format(time.RFC3339)
	m.logger.Printf("[INFO] [stacks] %s: restored after a removal — sign-up closed again as after its setup (hosts %v)", name, hosts)
	return &SetupGateRecord{State: SetupGateOpen, Since: now, Hosts: hosts, OpenedAt: now, OpenedBy: SetupGateByRestore}, nil
}

// goNativeLock runs applyNativeLock in the background, one at a time per app (a press, the window and the loop
// can meet). The seam afterSetupSync makes it synchronous for tests.
func (m *Manager) goNativeLock(name string, lock bool, why string) {
	if _, busy := m.nativeLockBusy.LoadOrStore(name, true); busy {
		return
	}
	run := func() {
		defer m.nativeLockBusy.Delete(name)
		_ = m.applyNativeLock(name, lock, why)
	}
	if m.afterSetupSync {
		run()
		return
	}
	go run()
}

// SetupGateByCloseSignup marks a lock record written by "close sign-up now" (the app was never gated).
const SetupGateByCloseSignup = "close-signup"

// composeMissingVars lists the after_setup env keys the compose file never reads as ${KEY...}.
func composeMissingVars(composePath string, env map[string]string) []string {
	b, err := os.ReadFile(composePath)
	if err != nil {
		keys := make([]string, 0, len(env))
		for k := range env {
			keys = append(keys, k)
		}
		sort.Strings(keys)
		return keys
	}
	var miss []string
	for k := range env {
		if !strings.Contains(string(b), "${"+k+"}") && !strings.Contains(string(b), "${"+k+":") {
			miss = append(miss, k)
		}
	}
	sort.Strings(miss)
	return miss
}