package cluster

import (
	"context"
	"errors"
	"fmt"
	"strings"
	"testing"
	"time"

	"scm.bstein.dev/bstein/ananke/internal/config"
)

// TestRepairBrokenKubeletProxiesRestartsSchedulableNode runs one orchestration or CLI step.
// Signature: TestRepairBrokenKubeletProxiesRestartsSchedulableNode(t *testing.T).
// Why: Jenkins agents depend on apiserver-to-kubelet exec; a Ready node with a
// broken proxy needs a narrow k3s-agent restart, not a broad cluster restart.
func TestRepairBrokenKubeletProxiesRestartsSchedulableNode(t *testing.T) {
	cfg := config.Config{SSHManagedNodes: []string{"titan-07"}}
	orch := buildOrchestratorWithStubs(t, cfg, nil)

	healthChecks := 0
	cordoned := false
	restarted := false
	waited := false
	uncordoned := false
	dispatch := func(_ context.Context, _ time.Duration, name string, args ...string) (string, error) {
		joined := strings.Join(args, " ")
		switch {
		case name == "kubectl" && strings.Contains(joined, "get nodes -o json"):
			return `{"items":[{"metadata":{"name":"titan-07"},"spec":{"unschedulable":false},"status":{"conditions":[{"type":"Ready","status":"True"}]}},{"metadata":{"name":"titan-18"},"status":{"conditions":[{"type":"Ready","status":"Unknown"}]}}]}`, nil
		case name == "kubectl" && strings.Contains(joined, "get --raw /api/v1/nodes/titan-07/proxy/healthz"):
			healthChecks++
			if healthChecks == 1 {
				return "proxy error from 127.0.0.1:6443 while dialing 192.168.22.33:10250, code 502: 502 Bad Gateway", errors.New("exit status 1")
			}
			return "ok", nil
		case name == "kubectl" && strings.Contains(joined, "uncordon titan-07"):
			uncordoned = true
			return "", nil
		case name == "kubectl" && strings.Contains(joined, "cordon titan-07"):
			cordoned = true
			return "", nil
		case name == "ssh" && strings.Contains(joined, "sudo -n systemctl restart k3s-agent"):
			restarted = true
			return "", nil
		case name == "kubectl" && strings.Contains(joined, "wait node/titan-07 --for=condition=Ready --timeout=120s"):
			waited = true
			return "", nil
		default:
			return "", nil
		}
	}
	orch.SetCommandOverrides(dispatch, dispatch)

	repaired, err := orch.repairBrokenKubeletProxies(context.Background())
	if err != nil {
		t.Fatalf("repairBrokenKubeletProxies failed: %v", err)
	}
	if repaired != 1 {
		t.Fatalf("expected one repaired node, got %d", repaired)
	}
	for name, ok := range map[string]bool{
		"cordoned":   cordoned,
		"restarted":  restarted,
		"waited":     waited,
		"uncordoned": uncordoned,
	} {
		if !ok {
			t.Fatalf("expected %s action", name)
		}
	}
	if healthChecks != 2 {
		t.Fatalf("expected health check before and after repair, got %d", healthChecks)
	}
}

// TestRepairBrokenKubeletProxiesPreservesExistingCordon runs one orchestration or CLI step.
// Signature: TestRepairBrokenKubeletProxiesPreservesExistingCordon(t *testing.T).
// Why: nodes intentionally kept out of service must not be accidentally
// uncordoned just because Ananke repaired their kubelet proxy.
func TestRepairBrokenKubeletProxiesPreservesExistingCordon(t *testing.T) {
	cfg := config.Config{SSHManagedNodes: []string{"titan-18"}}
	orch := buildOrchestratorWithStubs(t, cfg, nil)

	healthChecks := 0
	cordonTouched := false
	restarted := false
	dispatch := func(_ context.Context, _ time.Duration, name string, args ...string) (string, error) {
		joined := strings.Join(args, " ")
		switch {
		case name == "kubectl" && strings.Contains(joined, "get nodes -o json"):
			return `{"items":[{"metadata":{"name":"titan-18"},"spec":{"unschedulable":true},"status":{"conditions":[{"type":"Ready","status":"True"}]}}]}`, nil
		case name == "kubectl" && strings.Contains(joined, "get --raw /api/v1/nodes/titan-18/proxy/healthz"):
			healthChecks++
			if healthChecks == 1 {
				return "error trying to reach service: proxy error from 127.0.0.1:6443 while dialing 192.168.22.46:10250", errors.New("exit status 1")
			}
			return "ok", nil
		case name == "kubectl" && (strings.Contains(joined, "cordon titan-18") || strings.Contains(joined, "uncordon titan-18")):
			cordonTouched = true
			return "", nil
		case name == "ssh" && strings.Contains(joined, "sudo -n systemctl restart k3s-agent"):
			restarted = true
			return "", nil
		case name == "kubectl" && strings.Contains(joined, "wait node/titan-18 --for=condition=Ready --timeout=120s"):
			return "", nil
		default:
			return "", nil
		}
	}
	orch.SetCommandOverrides(dispatch, dispatch)

	repaired, err := orch.repairBrokenKubeletProxies(context.Background())
	if err != nil {
		t.Fatalf("repairBrokenKubeletProxies failed: %v", err)
	}
	if repaired != 1 {
		t.Fatalf("expected one repaired node, got %d", repaired)
	}
	if !restarted {
		t.Fatalf("expected k3s-agent restart")
	}
	if cordonTouched {
		t.Fatalf("did not expect cordon state to change for already-unschedulable node")
	}
}

// TestRepairBrokenKubeletProxiesFailureBranches runs one orchestration or CLI step.
// Signature: TestRepairBrokenKubeletProxiesFailureBranches(t *testing.T).
// Why: auto-repair must report exact blockers without broadening into unsafe
// node restarts for unrelated kubectl or access failures.
func TestRepairBrokenKubeletProxiesFailureBranches(t *testing.T) {
	t.Run("dry run skips", func(t *testing.T) {
		orch := buildOrchestratorWithStubs(t, config.Config{}, nil)
		orch.runner.DryRun = true
		repaired, err := orch.repairBrokenKubeletProxies(context.Background())
		if err != nil || repaired != 0 {
			t.Fatalf("expected dry-run skip, got repaired=%d err=%v", repaired, err)
		}
	})

	t.Run("node query error surfaces", func(t *testing.T) {
		orch := buildOrchestratorWithStubs(t, config.Config{}, []commandStub{
			{match: matchContains("kubectl", "get nodes -o json"), err: errors.New("api down")},
		})
		_, err := orch.repairBrokenKubeletProxies(context.Background())
		if err == nil || !strings.Contains(err.Error(), "query nodes") {
			t.Fatalf("expected node query error, got %v", err)
		}
	})

	t.Run("node json decode error surfaces", func(t *testing.T) {
		orch := buildOrchestratorWithStubs(t, config.Config{}, []commandStub{
			{match: matchContains("kubectl", "get nodes -o json"), out: `{bad json`},
		})
		_, err := orch.readyNodeCandidates(context.Background())
		if err == nil || !strings.Contains(err.Error(), "decode nodes") {
			t.Fatalf("expected decode error, got %v", err)
		}
	})

	t.Run("non repairable health error is reported", func(t *testing.T) {
		orch := kubeletProxyRepairStub(t, config.Config{}, false, []kubeletProxyRepairAction{
			{cmd: "health", out: "forbidden", err: errors.New("forbidden")},
		})
		repaired, err := orch.repairBrokenKubeletProxies(context.Background())
		if repaired != 0 || err == nil || !strings.Contains(err.Error(), "proxy health check") {
			t.Fatalf("expected health check error, repaired=%d err=%v", repaired, err)
		}
	})

	t.Run("unmanaged broken node is reported", func(t *testing.T) {
		cfg := config.Config{SSHManagedNodes: []string{"other"}}
		orch := kubeletProxyRepairStub(t, cfg, false, []kubeletProxyRepairAction{
			{cmd: "health", out: "502 bad gateway", err: errors.New("exit status 1")},
		})
		repaired, err := orch.repairBrokenKubeletProxies(context.Background())
		if repaired != 0 || err == nil || !strings.Contains(err.Error(), "not SSH-managed") {
			t.Fatalf("expected unmanaged node error, repaired=%d err=%v", repaired, err)
		}
	})

	t.Run("cordon failure is reported", func(t *testing.T) {
		orch := kubeletProxyRepairStub(t, config.Config{}, false, []kubeletProxyRepairAction{
			{cmd: "health", out: "502 bad gateway", err: errors.New("exit status 1")},
			{cmd: "cordon", err: errors.New("cordon denied")},
		})
		repaired, err := orch.repairBrokenKubeletProxies(context.Background())
		if repaired != 0 || err == nil || !strings.Contains(err.Error(), "cordon before kubelet restart") {
			t.Fatalf("expected cordon error, repaired=%d err=%v", repaired, err)
		}
	})

	t.Run("restart failure uncordons schedulable node", func(t *testing.T) {
		uncordoned := false
		orch := kubeletProxyRepairStub(t, config.Config{}, false, []kubeletProxyRepairAction{
			{cmd: "health", out: "502 bad gateway", err: errors.New("exit status 1")},
			{cmd: "cordon"},
			{cmd: "restart", err: errors.New("sudo rejected")},
			{cmd: "uncordon", sideEffect: func() { uncordoned = true }},
		})
		repaired, err := orch.repairBrokenKubeletProxies(context.Background())
		if repaired != 0 || err == nil || !strings.Contains(err.Error(), "restart k3s-agent") {
			t.Fatalf("expected restart error, repaired=%d err=%v", repaired, err)
		}
		if !uncordoned {
			t.Fatalf("expected best-effort uncordon after restart failure")
		}
	})

	t.Run("wait failure is reported", func(t *testing.T) {
		orch := kubeletProxyRepairStub(t, config.Config{}, false, []kubeletProxyRepairAction{
			{cmd: "health", out: "502 bad gateway", err: errors.New("exit status 1")},
			{cmd: "cordon"},
			{cmd: "restart"},
			{cmd: "wait", err: errors.New("not ready")},
		})
		repaired, err := orch.repairBrokenKubeletProxies(context.Background())
		if repaired != 0 || err == nil || !strings.Contains(err.Error(), "wait Ready") {
			t.Fatalf("expected wait error, repaired=%d err=%v", repaired, err)
		}
	})

	t.Run("post restart health failure is reported", func(t *testing.T) {
		orch := kubeletProxyRepairStub(t, config.Config{}, false, []kubeletProxyRepairAction{
			{cmd: "health", out: "502 bad gateway", err: errors.New("exit status 1")},
			{cmd: "cordon"},
			{cmd: "restart"},
			{cmd: "wait"},
			{cmd: "health", out: "failed to find Session for client", err: errors.New("exit status 1")},
		})
		repaired, err := orch.repairBrokenKubeletProxies(context.Background())
		if repaired != 0 || err == nil || !strings.Contains(err.Error(), "proxy still broken") {
			t.Fatalf("expected post-restart health error, repaired=%d err=%v", repaired, err)
		}
	})

	t.Run("uncordon failure is reported", func(t *testing.T) {
		orch := kubeletProxyRepairStub(t, config.Config{}, false, []kubeletProxyRepairAction{
			{cmd: "health", out: "502 bad gateway", err: errors.New("exit status 1")},
			{cmd: "cordon"},
			{cmd: "restart"},
			{cmd: "wait"},
			{cmd: "health", out: "ok"},
			{cmd: "uncordon", err: errors.New("uncordon denied")},
		})
		repaired, err := orch.repairBrokenKubeletProxies(context.Background())
		if repaired != 0 || err == nil || !strings.Contains(err.Error(), "uncordon after kubelet proxy repair") {
			t.Fatalf("expected uncordon error, repaired=%d err=%v", repaired, err)
		}
	})
}

type kubeletProxyRepairAction struct {
	cmd        string
	out        string
	err        error
	sideEffect func()
}

// kubeletProxyRepairStub runs one orchestration or CLI step.
// Signature: kubeletProxyRepairStub(t *testing.T, cfg config.Config, unschedulable bool, actions []kubeletProxyRepairAction) *Orchestrator.
// Why: keeps the kubelet proxy repair branch tests readable while preserving
// strict command order for safety-sensitive node operations.
func kubeletProxyRepairStub(t *testing.T, cfg config.Config, unschedulable bool, actions []kubeletProxyRepairAction) *Orchestrator {
	t.Helper()
	orch := buildOrchestratorWithStubs(t, cfg, nil)
	index := 0
	dispatch := func(_ context.Context, _ time.Duration, name string, args ...string) (string, error) {
		joined := strings.Join(args, " ")
		if name == "kubectl" && strings.Contains(joined, "get nodes -o json") {
			return fmt.Sprintf(`{"items":[{"metadata":{"name":"titan-07"},"spec":{"unschedulable":%t},"status":{"conditions":[{"type":"Ready","status":"True"}]}}]}`, unschedulable), nil
		}
		actual := ""
		switch {
		case name == "kubectl" && strings.Contains(joined, "get --raw /api/v1/nodes/titan-07/proxy/healthz"):
			actual = "health"
		case name == "kubectl" && strings.Contains(joined, "uncordon titan-07"):
			actual = "uncordon"
		case name == "kubectl" && strings.Contains(joined, "cordon titan-07"):
			actual = "cordon"
		case name == "ssh" && strings.Contains(joined, "sudo -n systemctl restart k3s-agent"):
			actual = "restart"
		case name == "kubectl" && strings.Contains(joined, "wait node/titan-07 --for=condition=Ready --timeout=120s"):
			actual = "wait"
		default:
			return "", nil
		}
		if index >= len(actions) {
			t.Fatalf("unexpected %s command after actions exhausted: %s %s", actual, name, joined)
		}
		action := actions[index]
		index++
		if action.cmd != actual {
			t.Fatalf("expected %s command, got %s (%s %s)", action.cmd, actual, name, joined)
		}
		if action.sideEffect != nil {
			action.sideEffect()
		}
		return action.out, action.err
	}
	orch.SetCommandOverrides(dispatch, dispatch)
	return orch
}

// TestKubeletProxyHealthAndRepairableErrorHelpers runs one orchestration or CLI step.
// Signature: TestKubeletProxyHealthAndRepairableErrorHelpers(t *testing.T).
// Why: helper branches decide whether Ananke restarts a node agent, so both
// positive and negative cases need direct coverage.
func TestKubeletProxyHealthAndRepairableErrorHelpers(t *testing.T) {
	t.Run("health error without output is preserved", func(t *testing.T) {
		orch := buildOrchestratorWithStubs(t, config.Config{}, []commandStub{
			{
				match: matchContains("kubectl", "get --raw /api/v1/nodes/titan-07/proxy/healthz"),
				err:   errors.New("network timeout"),
			},
		})
		healthy, err := orch.kubeletProxyHealthy(context.Background(), "titan-07")
		if healthy || err == nil || !strings.Contains(err.Error(), "network timeout") {
			t.Fatalf("expected raw health error, healthy=%v err=%v", healthy, err)
		}
	})

	for _, tc := range []struct {
		name string
		err  error
		want bool
	}{
		{name: "nil", err: nil, want: false},
		{name: "repairable", err: errors.New("502 Bad Gateway while dialing 10250"), want: true},
		{name: "not repairable", err: errors.New("forbidden"), want: false},
	} {
		t.Run(tc.name, func(t *testing.T) {
			if got := isRepairableKubeletProxyErr(tc.err); got != tc.want {
				t.Fatalf("isRepairableKubeletProxyErr()=%v want %v", got, tc.want)
			}
		})
	}
}