package executor

import (
	"sync"
	"testing"
	"time"

	"github.com/OliveTin/OliveTin/internal/auth"
	config "github.com/OliveTin/OliveTin/internal/config"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
)

func testGroupExecutor(actions []*config.Action, groups map[string]*config.ActionGroup) (*Executor, *config.Config) {
	cfg := config.DefaultConfig()
	cfg.ActionGroups = groups
	cfg.Actions = actions
	cfg.Sanitize()

	e := DefaultExecutor(cfg)
	e.RebuildActionMap()

	return e, cfg
}

func TestGroupConcurrencyQueuesSecondAction(t *testing.T) {
	t.Parallel()

	slowAction := &config.Action{
		Title:  "Unity Job 1",
		Shell:  "sleep 2",
		Groups: []string{"unity"},
	}
	fastAction := &config.Action{
		Title:  "Unity Job 2",
		Shell:  "echo queued-run",
		Groups: []string{"unity"},
	}

	e, cfg := testGroupExecutor(
		[]*config.Action{slowAction, fastAction},
		map[string]*config.ActionGroup{
			"unity": {MaxConcurrent: 1},
		},
	)

	binding1 := e.FindBindingWithNoEntity(slowAction)
	binding2 := e.FindBindingWithNoEntity(fastAction)
	require.NotNil(t, binding1)
	require.NotNil(t, binding2)

	wg1, tracking1 := e.ExecRequest(&ExecutionRequest{
		Binding:           binding1,
		Cfg:               cfg,
		AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
	})

	waitUntilExecutionStarted(t, e, tracking1)

	wg2, tracking2 := e.ExecRequest(&ExecutionRequest{
		Binding:           binding2,
		Cfg:               cfg,
		AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
	})

	require.Eventually(t, func() bool {
		snapshot, ok := e.SnapshotLog(tracking2)
		return ok && snapshot.Queued
	}, time.Second, 10*time.Millisecond)

	wg1.Wait()
	wg2.Wait()

	snapshot, ok := e.SnapshotLog(tracking2)
	require.True(t, ok)
	assert.False(t, snapshot.Queued)
	assert.False(t, snapshot.Blocked)
	assert.Equal(t, int32(0), snapshot.ExitCode)
	assert.Contains(t, snapshot.Output, "queued-run")
}

func TestQueuedActionNotifiesWhenExecutionBegins(t *testing.T) {
	t.Parallel()

	slowAction := &config.Action{
		Title:  "Hold group",
		Shell:  "sleep 1",
		Groups: []string{"unity"},
	}
	queuedAction := &config.Action{
		Title:  "Queued job",
		Shell:  "echo queued-run",
		Groups: []string{"unity"},
	}

	e, cfg := testGroupExecutor(
		[]*config.Action{slowAction, queuedAction},
		map[string]*config.ActionGroup{
			"unity": {MaxConcurrent: 1},
		},
	)

	notifications := make(chan startedNotification, 8)
	e.AddListener(&executionStartedCollector{ch: notifications})

	wg1, tracking1 := e.ExecRequest(&ExecutionRequest{
		Binding:           e.FindBindingWithNoEntity(slowAction),
		Cfg:               cfg,
		AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
	})

	waitUntilExecutionStarted(t, e, tracking1)

	wg2, tracking2 := e.ExecRequest(&ExecutionRequest{
		Binding:           e.FindBindingWithNoEntity(queuedAction),
		Cfg:               cfg,
		AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
	})

	require.Eventually(t, func() bool {
		snapshot, ok := e.SnapshotLog(tracking2)
		return ok && snapshot.Queued
	}, time.Second, 10*time.Millisecond)

	wg1.Wait()
	wg2.Wait()

	sawQueuedStart, sawRunningStart := collectQueuedStartNotifications(notifications, tracking2)

	assert.True(t, sawQueuedStart, "queued action should notify when queued")
	assert.True(t, sawRunningStart, "queued action should notify again when execution begins")
}

func isQueuedStartNotification(notification startedNotification, trackingID string) bool {
	return notification.trackingID == trackingID && notification.queued && !notification.started
}

func isRunningStartNotification(notification startedNotification, trackingID string) bool {
	return notification.trackingID == trackingID && !notification.queued && notification.started
}

func collectQueuedStartNotifications(notifications <-chan startedNotification, trackingID string) (sawQueuedStart, sawRunningStart bool) {
	for len(notifications) > 0 {
		notification := <-notifications
		if isQueuedStartNotification(notification, trackingID) {
			sawQueuedStart = true
		}
		if isRunningStartNotification(notification, trackingID) {
			sawRunningStart = true
		}
	}
	return sawQueuedStart, sawRunningStart
}

func TestDifferentGroupsRunConcurrently(t *testing.T) {
	t.Parallel()

	actionA := &config.Action{
		Title:  "Group A Job",
		Shell:  "sleep 1",
		Groups: []string{"groupA"},
	}
	actionB := &config.Action{
		Title:  "Group B Job",
		Shell:  "echo group-b",
		Groups: []string{"groupB"},
	}

	e, cfg := testGroupExecutor(
		[]*config.Action{actionA, actionB},
		map[string]*config.ActionGroup{
			"groupA": {MaxConcurrent: 1},
			"groupB": {MaxConcurrent: 1},
		},
	)

	wg1, tracking1 := e.ExecRequest(&ExecutionRequest{
		Binding:           e.FindBindingWithNoEntity(actionA),
		Cfg:               cfg,
		AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
	})

	waitUntilExecutionStarted(t, e, tracking1)

	wg2, tracking2 := e.ExecRequest(&ExecutionRequest{
		Binding:           e.FindBindingWithNoEntity(actionB),
		Cfg:               cfg,
		AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
	})

	require.Eventually(t, func() bool {
		snapshot, ok := e.SnapshotLog(tracking2)
		return ok && snapshot.ExecutionFinished && !snapshot.Queued
	}, 2*time.Second, 20*time.Millisecond)

	wg1.Wait()
	wg2.Wait()

	snapshot, ok := e.SnapshotLog(tracking2)
	require.True(t, ok)
	assert.Contains(t, snapshot.Output, "group-b")
}

func TestPerActionConcurrencyStillBlocksWithoutQueue(t *testing.T) {
	t.Parallel()

	action := &config.Action{
		Title:         "Single binding",
		Shell:         "sleep 1",
		MaxConcurrent: 1,
	}

	e, cfg := testGroupExecutor([]*config.Action{action}, nil)
	binding := e.FindBindingWithNoEntity(action)

	wg1, tracking1 := e.ExecRequest(&ExecutionRequest{
		Binding:           binding,
		Cfg:               cfg,
		AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
	})

	waitUntilExecutionStarted(t, e, tracking1)

	wg2, tracking2 := e.ExecRequest(&ExecutionRequest{
		Binding:           binding,
		Cfg:               cfg,
		AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
	})

	wg1.Wait()
	wg2.Wait()

	snapshot, ok := e.SnapshotLog(tracking2)
	require.True(t, ok)
	assert.True(t, snapshot.Blocked)
	assert.False(t, snapshot.Queued)
}

func TestGroupedSameBindingQueuesWhenGroupFull(t *testing.T) {
	t.Parallel()

	action := &config.Action{
		Title:  "Single binding grouped",
		Shell:  "sleep 1",
		Groups: []string{"unity"},
	}

	e, cfg := testGroupExecutor(
		[]*config.Action{action},
		map[string]*config.ActionGroup{
			"unity": {MaxConcurrent: 1, QueueSize: 5},
		},
	)
	binding := e.FindBindingWithNoEntity(action)

	wg1, tracking1 := e.ExecRequest(&ExecutionRequest{
		Binding:           binding,
		Cfg:               cfg,
		AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
	})

	waitUntilExecutionStarted(t, e, tracking1)

	wg2, tracking2 := e.ExecRequest(&ExecutionRequest{
		Binding:           binding,
		Cfg:               cfg,
		AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
	})

	require.Eventually(t, func() bool {
		snapshot, ok := e.SnapshotLog(tracking2)
		return ok && snapshot.Queued
	}, time.Second, 10*time.Millisecond)

	wg1.Wait()
	wg2.Wait()

	snapshot, ok := e.SnapshotLog(tracking2)
	require.True(t, ok)
	assert.False(t, snapshot.Blocked)
}

func TestGroupAllowsTwoConcurrentSameBinding(t *testing.T) {
	t.Parallel()

	action := &config.Action{
		Title:  "Long running action",
		Shell:  "sleep 1",
		Groups: []string{"con2queue10"},
	}

	e, cfg := testGroupExecutor(
		[]*config.Action{action},
		map[string]*config.ActionGroup{
			"con2queue10": {MaxConcurrent: 2, QueueSize: 10},
		},
	)
	binding := e.FindBindingWithNoEntity(action)

	wg1, tracking1 := e.ExecRequest(&ExecutionRequest{
		Binding:           binding,
		Cfg:               cfg,
		AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
	})

	waitUntilExecutionStarted(t, e, tracking1)

	wg2, tracking2 := e.ExecRequest(&ExecutionRequest{
		Binding:           binding,
		Cfg:               cfg,
		AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
	})

	require.Eventually(t, func() bool {
		snapshot, ok := e.SnapshotLog(tracking2)
		return ok && snapshot.ExecutionStarted && !snapshot.Queued && !snapshot.Blocked
	}, 2*time.Second, 10*time.Millisecond)

	wg1.Wait()
	wg2.Wait()

	snapshot, ok := e.SnapshotLog(tracking2)
	require.True(t, ok)
	assert.False(t, snapshot.Blocked)
	assert.False(t, snapshot.Queued)
}

func TestGroupQueuesThirdAndBlocksWhenQueueFull(t *testing.T) {
	t.Parallel()

	action := &config.Action{
		Title:  "Long running action",
		Shell:  "sleep 1",
		Groups: []string{"con2queue10"},
	}

	e, cfg := testGroupExecutor(
		[]*config.Action{action},
		map[string]*config.ActionGroup{
			"con2queue10": {MaxConcurrent: 2, QueueSize: 2},
		},
	)
	binding := e.FindBindingWithNoEntity(action)

	wg1, tracking1 := e.ExecRequest(&ExecutionRequest{
		Binding:           binding,
		Cfg:               cfg,
		AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
	})
	waitUntilExecutionStarted(t, e, tracking1)

	wg2, tracking2 := e.ExecRequest(&ExecutionRequest{
		Binding:           binding,
		Cfg:               cfg,
		AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
	})
	waitUntilExecutionStarted(t, e, tracking2)

	trackings := []string{tracking1, tracking2}
	waitGroups := []*sync.WaitGroup{wg1, wg2}

	for idx := 0; idx < 3; idx++ {
		wg, tracking := e.ExecRequest(&ExecutionRequest{
			Binding:           binding,
			Cfg:               cfg,
			AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
		})
		trackings = append(trackings, tracking)
		waitGroups = append(waitGroups, wg)
	}

	require.Eventually(t, func() bool {
		return groupExecutionDistributionMatches(e, trackings, 2, 2, 1)
	}, 2*time.Second, 20*time.Millisecond)

	for _, wg := range waitGroups {
		wg.Wait()
	}
}

func waitUntilExecutionStarted(t *testing.T, e *Executor, trackingID string) {
	t.Helper()

	require.Eventually(t, func() bool {
		snapshot, ok := e.SnapshotLog(trackingID)
		return ok && snapshot.ExecutionStarted
	}, 2*time.Second, 10*time.Millisecond)
}

type executionStartedCollector struct {
	ch chan startedNotification
}

type startedNotification struct {
	trackingID string
	started    bool
	queued     bool
}

func (c *executionStartedCollector) OnExecutionStarted(entry *InternalLogEntry) {
	c.ch <- startedNotification{
		trackingID: entry.ExecutionTrackingID,
		started:    entry.ExecutionStarted,
		queued:     entry.Queued,
	}
}

func (c *executionStartedCollector) OnExecutionFinished(_ *InternalLogEntry) {}

func (c *executionStartedCollector) OnOutputChunk(_ []byte, _ string) {}

func (c *executionStartedCollector) OnActionMapRebuilt() {}

func assertWaitGroupPending(t *testing.T, wg *sync.WaitGroup) {
	t.Helper()

	done := make(chan struct{})

	go func() {
		wg.Wait()
		close(done)
	}()

	select {
	case <-done:
		t.Fatal("wait group completed before queued execution finished")
	case <-time.After(100 * time.Millisecond):
	}
}

func assertWaitGroupCompletes(t *testing.T, wg *sync.WaitGroup) {
	t.Helper()

	done := make(chan struct{})

	go func() {
		wg.Wait()
		close(done)
	}()

	select {
	case <-done:
	case <-time.After(3 * time.Second):
		t.Fatal("wait group did not complete after queue drained")
	}
}

func TestStartActionAndWaitWaitsForQueuedExecution(t *testing.T) {
	t.Parallel()

	first := &config.Action{
		Title:  "Hold group",
		Shell:  "sleep 1",
		Groups: []string{"unity"},
	}
	second := &config.Action{
		Title:  "Wait in queue",
		Shell:  "echo waited",
		Groups: []string{"unity"},
	}

	e, cfg := testGroupExecutor(
		[]*config.Action{first, second},
		map[string]*config.ActionGroup{
			"unity": {MaxConcurrent: 1},
		},
	)

	wg1, tracking1 := e.ExecRequest(&ExecutionRequest{
		Binding:           e.FindBindingWithNoEntity(first),
		Cfg:               cfg,
		AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
	})

	waitUntilExecutionStarted(t, e, tracking1)

	wg2, tracking2 := e.ExecRequest(&ExecutionRequest{
		Binding:           e.FindBindingWithNoEntity(second),
		Cfg:               cfg,
		AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
	})

	assertWaitGroupPending(t, wg2)

	wg1.Wait()

	assertWaitGroupCompletes(t, wg2)

	snapshot, ok := e.SnapshotLog(tracking2)
	require.True(t, ok)
	assert.Contains(t, snapshot.Output, "waited")
}

func TestGroupQueueBlocksWhenQueueFull(t *testing.T) {
	t.Parallel()

	actions := []*config.Action{
		{Title: "Hold 1", Shell: "sleep 1", Groups: []string{"unity"}},
		{Title: "Hold 2", Shell: "sleep 1", Groups: []string{"unity"}},
		{Title: "Hold 3", Shell: "sleep 1", Groups: []string{"unity"}},
		{Title: "Hold 4", Shell: "sleep 1", Groups: []string{"unity"}},
	}

	e, cfg := testGroupExecutor(
		actions,
		map[string]*config.ActionGroup{
			"unity": {MaxConcurrent: 1, QueueSize: 2},
		},
	)

	trackings, waitGroups := execAllGroupActions(t, e, cfg, actions)

	require.Eventually(t, func() bool {
		return countSnapshots(e, trackings, func(snapshot LogEntrySnapshot) bool { return snapshot.Blocked }) == 1 &&
			countSnapshots(e, trackings, func(snapshot LogEntrySnapshot) bool { return snapshot.Queued }) == 2 &&
			countSnapshots(e, trackings, isRunningSnapshot) == 1
	}, 2*time.Second, 20*time.Millisecond)

	for _, wg := range waitGroups {
		wg.Wait()
	}
}

func execAllGroupActions(t *testing.T, e *Executor, cfg *config.Config, actions []*config.Action) ([]string, []*sync.WaitGroup) {
	t.Helper()

	trackings := make([]string, len(actions))
	waitGroups := make([]*sync.WaitGroup, len(actions))

	for idx, action := range actions {
		wg, tracking := e.ExecRequest(&ExecutionRequest{
			Binding:           e.FindBindingWithNoEntity(action),
			Cfg:               cfg,
			AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
		})
		trackings[idx] = tracking
		waitGroups[idx] = wg
	}

	return trackings, waitGroups
}

func groupExecutionDistributionMatches(e *Executor, trackings []string, wantRunning, wantQueued, wantBlocked int) bool {
	running := countSnapshots(e, trackings, isRunningSnapshot)
	queued := countSnapshots(e, trackings, func(snapshot LogEntrySnapshot) bool { return snapshot.Queued })
	blocked := countSnapshots(e, trackings, func(snapshot LogEntrySnapshot) bool { return snapshot.Blocked })
	return running == wantRunning && queued == wantQueued && blocked == wantBlocked
}

func countSnapshots(e *Executor, trackings []string, matches func(LogEntrySnapshot) bool) int {
	count := 0

	for _, tracking := range trackings {
		snapshot, ok := e.SnapshotLog(tracking)
		if ok && matches(snapshot) {
			count++
		}
	}

	return count
}

func isRunningSnapshot(snapshot LogEntrySnapshot) bool {
	return snapshot.ExecutionStarted && !snapshot.ExecutionFinished
}

func TestUnknownActionGroupReferenceWarnsAndSkipsLimit(t *testing.T) {
	t.Parallel()

	action := &config.Action{
		Title:  "Unknown group action",
		Shell:  "echo ok",
		Groups: []string{"missing"},
	}

	e, cfg := testGroupExecutor([]*config.Action{action}, map[string]*config.ActionGroup{})
	wg, tracking := e.ExecRequest(&ExecutionRequest{
		Binding:           e.FindBindingWithNoEntity(action),
		Cfg:               cfg,
		AuthenticatedUser: auth.UserFromSystem(cfg, "testuser"),
	})

	wg.Wait()

	snapshot, ok := e.SnapshotLog(tracking)
	require.True(t, ok)
	assert.False(t, snapshot.Queued)
	assert.Equal(t, int32(0), snapshot.ExitCode)
}