package host

import (
	"context"
	"encoding/json"
	"errors"
	"os"
	"os/exec"
	"path/filepath"
	"testing"
	"time"

	"github.com/carlosframework/platform/internal/hostbox"
	"github.com/carlosframework/platform/internal/hostclaim"
	"github.com/carlosframework/platform/internal/hostguard"
	"github.com/carlosframework/platform/internal/hostwrite"
	"github.com/carlosframework/platform/internal/registry"
	"github.com/carlosframework/platform/internal/release"
	"github.com/carlosframework/platform/internal/rootparticipation"
)

type restartRequestProcessFixture struct {
	Unit                   rollbackProcessFixture
	Claim                  *hostclaim.Claim
	Installations, Journal string
}

func TestPlan14RootRestartProductionCrash(t *testing.T) {
	t.Parallel()
	if boundary := os.Getenv("PLAN14_REQUEST_CRASH"); boundary != "" {
		dir := os.Getenv("PLAN14_REQUEST_DIR")
		f := newRestartConsumptionFixture(t)
		if err := f.run(t); err != nil {
			t.Fatal(err)
		}
		f.request(t, release.RestartScopeHost, observedHost)
		storeDir := filepath.Join(dir, "deployment")
		store := release.NewDirStore(storeDir)
		keys, err := f.e.store.List(t.Context(), "")
		if err != nil {
			t.Fatal(err)
		}
		for _, key := range keys {
			raw, _, err := f.e.store.Get(t.Context(), key)
			if err != nil {
				t.Fatal(err)
			}
			if _, err := store.Put(t.Context(), key, raw, ""); err != nil {
				t.Fatal(err)
			}
		}
		crash := func() {
			state := restartRequestProcessFixture{Unit: rollbackProcessFixture{Props: f.u.props, Exe: f.u.exe, Opt: f.u.opt, Bake: f.e.bake, Store: storeDir, Effects: f.u.effects}, Claim: f.claim,
				Installations: f.p.source.state.(*rollbackDisk).dir, Journal: f.p.journal.Store.(*rollbackDisk).dir}
			raw, err := json.Marshal(state)
			if err != nil {
				t.Fatal(err)
			}
			if err := os.WriteFile(filepath.Join(dir, "fixture.json"), raw, 0600); err != nil {
				t.Fatal(err)
			}
			os.Exit(74)
		}
		disk := f.p.journal.Store.(*rollbackDisk)
		classify := func(raw []byte) string {
			var r struct {
				Pending *release.RestartIntent
				ScopeID string `json:"scope_id"`
			}
			if json.Unmarshal(raw, &r) != nil {
				return ""
			}
			if r.Pending == nil {
				if r.ScopeID != release.RestartScopeNone {
					return "consumed"
				}
				return "baseline"
			}
			if r.Pending.Targets[0].After != "" {
				return "completed"
			}
			if r.Pending.Targets[0].Before != "" {
				return "intent"
			}
			return "pending"
		}
		disk.afterWrite = func(_ string, raw []byte) {
			if classify(raw) == boundary {
				crash()
			}
		}
		if boundary == "intent-visible" {
			disk.beforeWrite = func(name string, raw []byte) {
				if classify(raw) != "intent" {
					return
				}
				file, err := os.CreateTemp(disk.dir, "visible-")
				if err != nil {
					t.Fatal(err)
				}
				if _, err = file.Write(raw); err != nil {
					t.Fatal(err)
				}
				if err = file.Sync(); err != nil {
					t.Fatal(err)
				}
				if err = file.Close(); err != nil {
					t.Fatal(err)
				}
				if err = os.Rename(file.Name(), filepath.Join(disk.dir, name)); err != nil {
					t.Fatal(err)
				}
				// Exit before syncing the parent of the visible rename.
				crash()
			}
		}
		f.u.afterEffect = func() {
			if boundary == "effect" {
				crash()
			}
		}
		_ = f.run(t)
		t.Fatal("crash boundary not reached")
	}
	for _, boundary := range []string{"pending", "intent", "intent-visible", "effect", "completed", "consumed"} {
		t.Run(boundary, func(t *testing.T) {
			dir := t.TempDir()
			ctx, cancel := context.WithTimeout(t.Context(), 30*time.Second)
			defer cancel()
			cmd := exec.CommandContext(ctx, os.Args[0], "-test.run=^TestPlan14RootRestartProductionCrash$", "-test.count=1")
			cmd.Dir = dir
			cmd.Env = append(os.Environ(), "TMPDIR="+dir, "PLAN14_REQUEST_DIR="+dir, "PLAN14_REQUEST_CRASH="+boundary, "CARLOS_HOST_CLAIM=")
			out, err := cmd.CombinedOutput()
			var exit *exec.ExitError
			if !errors.As(err, &exit) || exit.ExitCode() != 74 {
				t.Fatalf("child: %v\n%s", err, out)
			}
			raw, err := os.ReadFile(filepath.Join(dir, "fixture.json"))
			if err != nil {
				t.Fatal(err)
			}
			var saved restartRequestProcessFixture
			if err = json.Unmarshal(raw, &saved); err != nil {
				t.Fatal(err)
			}
			u := &plan14RestartUnits{props: saved.Unit.Props, exe: saved.Unit.Exe, opt: saved.Unit.Opt, effects: saved.Unit.Effects}
			store := release.NewDirStore(saved.Unit.Store)
			state := &rollbackDisk{dir: saved.Installations}
			guard := hostguard.Guard{DataDir: t.TempDir(), LockDir: t.TempDir(), Root: hostguard.NewRootAuthority(state), Claims: rootViewClaimReader{obs: hostclaim.Observed{Host: observedHost, ETag: "claim", Claim: saved.Claim}}}
			source := &proofBindingSource{store: store, sys: u, optDir: u.opt, openFile: os.Open, unitDirs: []string{filepath.Dir(u.props.FragmentPath)}, healthy: func(acct, app, version, digest string) *release.HealthyBuild {
				for _, b := range release.ReadHealthy(saved.Unit.Bake, acct, app) {
					if b.Version == version && b.SHA256 == digest {
						return &b
					}
				}
				return nil
			}}
			now, sleep := settleClock()
			p := rootRestartRequests{journal: &release.RootRestarts{Store: &rollbackDisk{dir: saved.Journal}}, source: rootRestartRequestSource{state: state, store: store, census: func() (rootparticipation.Census, error) {
				return rootparticipation.Census{Box: "box", Enrollment: "en", Migration: 1, Complete: true}, nil
			}},
				sys: u, optDir: u.opt, getenv: func(string) string { return "5s" }, checks: rootRestartChecks{host: source.forHost, ready: func(registry.Route) func() error { return func() error { return nil } }, now: now, sleep: sleep},
				writes: hostwrite.Config{Enabled: true, Selector: hostbox.WorkSource{Guard: guard, Box: "box", Region: "ie", Now: time.Now, Policy: func(_ context.Context, c *hostclaim.Claim, s hostbox.Selection, _ hostwrite.Identity) error {
					return hostbox.Serving(c, s)
				}, Local: func(context.Context, *hostclaim.Claim, hostbox.Selection) error { return nil }}}}
			err = p.run(t.Context())
			if boundary == "intent" || boundary == "intent-visible" {
				if err == nil || len(u.effects) != 0 {
					t.Fatalf("ambiguous replay: %v %v", err, u.effects)
				}
				u.props.InvocationID += "reconciled"
				u.props.MainPID++
				if err = p.run(t.Context()); err != nil || len(u.effects) != 0 {
					t.Fatalf("reconcile: %v %v", err, u.effects)
				}
			} else if err != nil || len(u.effects) != 1 {
				t.Fatalf("resume: %v %v", err, u.effects)
			}
			count := len(u.effects)
			if err = p.run(t.Context()); err != nil || len(u.effects) != count {
				t.Fatalf("replay: %v %v", err, u.effects)
			}
		})
	}
}