// SPDX-License-Identifier: AGPL-3.0-only

package deploy

import (
	"context"
	"errors"
	"os"
	"path/filepath"
	"strings"
	"testing"
	"time"

	"gamertan.com/tend/internal/config"
	"gamertan.com/tend/internal/state"
)

type fakeOperator struct {
	failReload              bool
	failRestartUnit         string
	rejectMarkers           bool
	active                  map[string]bool
	starts, stops, restarts []string
	probes                  []string
}

func (f *fakeOperator) Restart(_ context.Context, unit string) error {
	f.restarts = append(f.restarts, unit)
	if unit == f.failRestartUnit {
		return errors.New("injected restart failure")
	}
	f.active[unit] = true
	return nil
}
func (f *fakeOperator) Stop(_ context.Context, unit string) error {
	f.stops = append(f.stops, unit)
	f.active[unit] = false
	return nil
}
func (f *fakeOperator) IsActive(_ context.Context, unit string) (bool, error) {
	return f.active[unit], nil
}
func (f *fakeOperator) StartCandidate(_ context.Context, unit, binary string, env map[string]string) error {
	if !filepath.IsAbs(binary) || len(env) == 0 {
		return errors.New("bad candidate")
	}
	f.starts = append(f.starts, unit)
	f.active[unit] = true
	return nil
}
func (f *fakeOperator) ValidateCaddy(context.Context, string) error { return nil }
func (f *fakeOperator) ReloadCaddy(context.Context) error {
	if f.failReload {
		return errors.New("injected reload failure")
	}
	return nil
}
func (f *fakeOperator) Probe(_ context.Context, address, host, path, contains string) error {
	f.probes = append(f.probes, address+path)
	if f.rejectMarkers && contains != "" {
		return errors.New("unexpected future-release smoke marker")
	}
	return nil
}

func baseConfig(t *testing.T, strategy string) (config.Config, string, string) {
	t.Helper()
	root := filepath.Join(t.TempDir(), "service")
	if err := os.MkdirAll(filepath.Join(root, "releases"), 0o755); err != nil {
		t.Fatal(err)
	}
	old := filepath.Join(root, "releases", "legacy-old")
	fresh := filepath.Join(root, "releases", "sha256-"+strings.Repeat("a", 64))
	for _, dir := range []string{old, fresh} {
		if err := os.Mkdir(dir, 0o755); err != nil {
			t.Fatal(err)
		}
		if err := os.WriteFile(filepath.Join(dir, "app"), []byte("x"), 0o755); err != nil {
			t.Fatal(err)
		}
	}
	cfg := config.Config{SchemaVersion: 1, Service: config.Service{Name: "example-site", AllowedHost: "example.test"}, Build: config.Build{Package: "./cmd/site", Binary: "app", Branch: "main"}, Deployment: config.Deployment{Strategy: strategy, Root: root, LockFile: filepath.Join(root, "deploy.lock"), StateFile: filepath.Join(root, "state.json"), HealthPath: "/healthz", ReadinessPath: "/readyz", CandidateTimeoutSecs: 2, Smoke: []config.Smoke{{Path: "/", Contains: "Example"}}}}
	return cfg, old, fresh
}
func manager(operator Operator, fresh string) Manager {
	return Manager{Operator: operator, Now: func() time.Time { return time.Unix(100, 0).UTC() }, Prepare: func(config.Config, string, string, string) (string, error) { return fresh, nil }, Inspect: func(config.Config, string, string, string) error { return nil }}
}

func TestBlueGreenActivationAndRollback(t *testing.T) {
	cfg, old, fresh := baseConfig(t, "blue_green")
	handler := filepath.Join(cfg.Deployment.Root, "handler.caddy")
	template := filepath.Join(cfg.Deployment.Root, "handler.template")
	if err := os.WriteFile(handler, []byte("reverse_proxy 127.0.0.1:8090\n"), 0o640); err != nil {
		t.Fatal(err)
	}
	if err := os.WriteFile(template, []byte("reverse_proxy {{UPSTREAM}}\n"), 0o644); err != nil {
		t.Fatal(err)
	}
	blue := filepath.Join(cfg.Deployment.Root, "slots", "blue")
	green := filepath.Join(cfg.Deployment.Root, "slots", "green")
	if err := replaceSymlink(blue, old); err != nil {
		t.Fatal(err)
	}
	if err := replaceSymlink(green, old); err != nil {
		t.Fatal(err)
	}
	cfg.Deployment.BlueGreen = &config.BlueGreen{CaddyConfig: filepath.Join(cfg.Deployment.Root, "Caddyfile"), CaddyHandler: handler, CaddyHandlerTemplate: template, BootstrapActive: "blue", Blue: config.Slot{Unit: "example-blue.service", Address: "127.0.0.1:8090", Link: blue}, Green: config.Slot{Unit: "example-green.service", Address: "127.0.0.1:8091", Link: green}}
	if err := cfg.Validate(); err != nil {
		t.Fatal(err)
	}
	operator := &fakeOperator{active: map[string]bool{"example-blue.service": true, "example-green.service": true}}
	m := manager(operator, fresh)
	report, err := m.Deploy(context.Background(), cfg, Request{Activate: true})
	if err != nil {
		t.Fatal(err)
	}
	if report.ActiveRelease != fresh || report.PreviousRelease != old {
		t.Fatalf("report=%+v", report)
	}
	if info, err := os.Stat(handler); err != nil || info.Mode().Perm() != 0o640 {
		t.Fatalf("handler mode=%v err=%v", info.Mode().Perm(), err)
	}
	if target, err := resolveReleaseLink(cfg.Deployment.Root, green); err != nil || target != fresh {
		t.Fatalf("green=%q err=%v", target, err)
	}
	operator.rejectMarkers = true
	operator.probes = nil
	record, err := m.Rollback(context.Background(), cfg)
	if err != nil {
		t.Fatal(err)
	}
	if record.ActiveRelease != old || record.PreviousRelease != fresh {
		t.Fatalf("rollback=%+v", record)
	}
	if len(operator.probes) != 4 {
		t.Fatalf("rollback probes=%#v", operator.probes)
	}
	for _, probe := range operator.probes {
		if !strings.HasSuffix(probe, "/healthz") && !strings.HasSuffix(probe, "/readyz") {
			t.Fatalf("rollback applied future-release smoke checks: %#v", operator.probes)
		}
	}
}

func TestBlueGreenCaddyFailureRestoresHandlerAndSlot(t *testing.T) {
	cfg, old, fresh := baseConfig(t, "blue_green")
	handler := filepath.Join(cfg.Deployment.Root, "handler.caddy")
	template := filepath.Join(cfg.Deployment.Root, "handler.template")
	original := []byte("reverse_proxy 127.0.0.1:8090\n")
	_ = os.WriteFile(handler, original, 0o644)
	_ = os.WriteFile(template, []byte("reverse_proxy {{UPSTREAM}}\n"), 0o644)
	blue := filepath.Join(cfg.Deployment.Root, "slots", "blue")
	green := filepath.Join(cfg.Deployment.Root, "slots", "green")
	_ = replaceSymlink(blue, old)
	_ = replaceSymlink(green, old)
	cfg.Deployment.BlueGreen = &config.BlueGreen{CaddyConfig: filepath.Join(cfg.Deployment.Root, "Caddyfile"), CaddyHandler: handler, CaddyHandlerTemplate: template, BootstrapActive: "blue", Blue: config.Slot{Unit: "example-blue.service", Address: "127.0.0.1:8090", Link: blue}, Green: config.Slot{Unit: "example-green.service", Address: "127.0.0.1:8091", Link: green}}
	operator := &fakeOperator{active: map[string]bool{}, failReload: true}
	m := manager(operator, fresh)
	if _, err := m.Deploy(context.Background(), cfg, Request{Activate: true}); err == nil {
		t.Fatal("expected failure")
	}
	body, _ := os.ReadFile(handler)
	if string(body) != string(original) {
		t.Fatalf("handler not restored: %q", body)
	}
	target, err := resolveReleaseLink(cfg.Deployment.Root, green)
	if err != nil || target != old {
		t.Fatalf("green=%q err=%v", target, err)
	}
	if _, err := os.Stat(cfg.Deployment.StateFile); !os.IsNotExist(err) {
		t.Fatal("failed activation wrote state")
	}
}

func TestSingletonRestartFailureRestoresPointers(t *testing.T) {
	cfg, old, fresh := baseConfig(t, "singleton_candidate")
	previous := filepath.Join(cfg.Deployment.Root, "previous")
	current := filepath.Join(cfg.Deployment.Root, "current")
	_ = replaceSymlink(current, old)
	cfg.Deployment.Singleton = &config.Singleton{Unit: "example-site.service", Address: "127.0.0.1:8092", CandidateAddress: "127.0.0.1:18092", ListenEnv: "EXAMPLE_LISTEN", CurrentLink: current, PreviousLink: previous}
	operator := &fakeOperator{active: map[string]bool{}, failRestartUnit: "example-site.service"}
	m := manager(operator, fresh)
	if _, err := m.Deploy(context.Background(), cfg, Request{Activate: true}); err == nil {
		t.Fatal("expected failure")
	}
	target, err := resolveReleaseLink(cfg.Deployment.Root, current)
	if err != nil || target != old {
		t.Fatalf("current=%q err=%v", target, err)
	}
	if _, err := os.Lstat(previous); !os.IsNotExist(err) {
		t.Fatal("previous pointer was not restored")
	}
}

func TestStatePersistsOnlyAfterSuccessfulActivation(t *testing.T) {
	cfg, old, fresh := baseConfig(t, "singleton_candidate")
	current := filepath.Join(cfg.Deployment.Root, "current")
	previous := filepath.Join(cfg.Deployment.Root, "previous")
	_ = replaceSymlink(current, old)
	cfg.Deployment.Singleton = &config.Singleton{Unit: "example-site.service", Address: "127.0.0.1:8092", CandidateAddress: "127.0.0.1:18092", ListenEnv: "EXAMPLE_LISTEN", CurrentLink: current, PreviousLink: previous}
	operator := &fakeOperator{active: map[string]bool{}}
	m := manager(operator, fresh)
	if _, err := m.Deploy(context.Background(), cfg, Request{Activate: true}); err != nil {
		t.Fatal(err)
	}
	record, err := state.Load(cfg.Deployment.StateFile, cfg.Deployment.Root, cfg.Deployment.Strategy)
	if err != nil {
		t.Fatal(err)
	}
	if record.ActiveRelease != fresh || record.PreviousRelease != old {
		t.Fatalf("state=%+v", record)
	}
}