package store

import (
	"testing"

	"task-dashboard/internal/models"
)

// chainTasks builds bare-content ChainTaskInputs (no description/priority)
// for tests that only care about title ordering and lock state.
func chainTasks(titles ...string) []models.ChainTaskInput {
	tasks := make([]models.ChainTaskInput, len(titles))
	for i, t := range titles {
		tasks[i] = models.ChainTaskInput{Content: t}
	}
	return tasks
}

func TestCreateChain_SeedsPositionsCorrectly(t *testing.T) {
	s := newNativeTasksTestStore(t)

	chain, err := s.CreateChain("Ham Radio Track", chainTasks("Study Technician", "Pass Technician exam", "Study General"))
	if err != nil {
		t.Fatalf("CreateChain: %v", err)
	}
	if chain.Status != "active" {
		t.Errorf("chain.Status = %q, want active", chain.Status)
	}

	tasks, err := s.GetChainTasks(chain.ID)
	if err != nil {
		t.Fatalf("GetChainTasks: %v", err)
	}
	if len(tasks) != 3 {
		t.Fatalf("len(tasks) = %d, want 3", len(tasks))
	}
	if !tasks[0].ChainUnlocked || tasks[0].DueDate == nil {
		t.Errorf("position 0: ChainUnlocked=%v DueDate=%v, want unlocked with a due date", tasks[0].ChainUnlocked, tasks[0].DueDate)
	}
	for i := 1; i < 3; i++ {
		if tasks[i].ChainUnlocked || tasks[i].DueDate != nil {
			t.Errorf("position %d: ChainUnlocked=%v DueDate=%v, want locked with no due date", i, tasks[i].ChainUnlocked, tasks[i].DueDate)
		}
	}
	if tasks[0].Content != "Study Technician" || tasks[1].Content != "Pass Technician exam" || tasks[2].Content != "Study General" {
		t.Errorf("unexpected content order: %q, %q, %q", tasks[0].Content, tasks[1].Content, tasks[2].Content)
	}
}

func TestCompleteNativeTask_AdvancesChain(t *testing.T) {
	s := newNativeTasksTestStore(t)

	chain, err := s.CreateChain("Track", chainTasks("Step 1", "Step 2"))
	if err != nil {
		t.Fatal(err)
	}
	tasks, err := s.GetChainTasks(chain.ID)
	if err != nil {
		t.Fatal(err)
	}

	if err := s.CompleteNativeTask(tasks[0].ID); err != nil {
		t.Fatalf("CompleteNativeTask: %v", err)
	}

	after, err := s.GetChainTasks(chain.ID)
	if err != nil {
		t.Fatal(err)
	}
	if !after[1].ChainUnlocked || after[1].DueDate == nil {
		t.Errorf("position 1 after completing position 0: ChainUnlocked=%v DueDate=%v, want unlocked with a due date", after[1].ChainUnlocked, after[1].DueDate)
	}

	updatedChain, err := s.GetChain(chain.ID)
	if err != nil {
		t.Fatal(err)
	}
	if updatedChain.Status != "active" {
		t.Errorf("chain.Status = %q, want active (not yet done)", updatedChain.Status)
	}
}

func TestCompleteNativeTask_LastPosition_MarksChainCompleted(t *testing.T) {
	s := newNativeTasksTestStore(t)

	chain, err := s.CreateChain("Track", chainTasks("Only step"))
	if err != nil {
		t.Fatal(err)
	}
	tasks, err := s.GetChainTasks(chain.ID)
	if err != nil {
		t.Fatal(err)
	}

	if err := s.CompleteNativeTask(tasks[0].ID); err != nil {
		t.Fatalf("CompleteNativeTask: %v", err)
	}

	updatedChain, err := s.GetChain(chain.ID)
	if err != nil {
		t.Fatal(err)
	}
	if updatedChain.Status != "completed" {
		t.Errorf("chain.Status = %q, want completed", updatedChain.Status)
	}
}

func TestCompleteNativeTask_PausedChain_DoesNotAdvance(t *testing.T) {
	s := newNativeTasksTestStore(t)

	chain, err := s.CreateChain("Track", chainTasks("Step 1", "Step 2"))
	if err != nil {
		t.Fatal(err)
	}
	if err := s.SetChainStatus(chain.ID, "paused"); err != nil {
		t.Fatal(err)
	}
	tasks, err := s.GetChainTasks(chain.ID)
	if err != nil {
		t.Fatal(err)
	}

	if err := s.CompleteNativeTask(tasks[0].ID); err != nil {
		t.Fatalf("CompleteNativeTask: %v", err)
	}

	after, err := s.GetChainTasks(chain.ID)
	if err != nil {
		t.Fatal(err)
	}
	if after[1].ChainUnlocked {
		t.Error("position 1 should still be locked while chain is paused")
	}

	// Resuming performs the deferred unlock itself -- position 1 becomes
	// completable immediately, not only after some future completion.
	if err := s.SetChainStatus(chain.ID, "active"); err != nil {
		t.Fatal(err)
	}
	resumed, err := s.GetChainTasks(chain.ID)
	if err != nil {
		t.Fatal(err)
	}
	if !resumed[1].ChainUnlocked {
		t.Fatal("expected resume to unlock position 1 immediately (deferred advancement catch-up)")
	}

	if err := s.CompleteNativeTask(tasks[1].ID); err != nil {
		t.Fatalf("CompleteNativeTask after resume: %v", err)
	}
	updatedChain, err := s.GetChain(chain.ID)
	if err != nil {
		t.Fatal(err)
	}
	if updatedChain.Status != "completed" {
		t.Errorf("chain.Status = %q, want completed after resuming and finishing the last step", updatedChain.Status)
	}
}

func TestCompleteNativeTask_LockedChainTask_ReturnsErrChainTaskLocked(t *testing.T) {
	s := newNativeTasksTestStore(t)

	chain, err := s.CreateChain("Track", chainTasks("Step 1", "Step 2"))
	if err != nil {
		t.Fatal(err)
	}
	tasks, err := s.GetChainTasks(chain.ID)
	if err != nil {
		t.Fatal(err)
	}

	if err := s.CompleteNativeTask(tasks[1].ID); err != ErrChainTaskLocked {
		t.Errorf("err = %v, want ErrChainTaskLocked", err)
	}

	// Confirm nothing was mutated -- still locked, still not completed.
	after, err := s.GetChainTasks(chain.ID)
	if err != nil {
		t.Fatal(err)
	}
	if after[1].Completed || after[1].ChainUnlocked {
		t.Errorf("locked task should be untouched by the rejected completion attempt: %+v", after[1])
	}
}

func TestSetChainStatus_ResumeWithNothingStuck_DoesNotResetDueDate(t *testing.T) {
	s := newNativeTasksTestStore(t)

	chain, err := s.CreateChain("Track", chainTasks("Step 1", "Step 2"))
	if err != nil {
		t.Fatal(err)
	}
	tasks, err := s.GetChainTasks(chain.ID)
	if err != nil {
		t.Fatal(err)
	}
	originalDueDate := *tasks[0].DueDate

	// Pause and resume with nothing completed yet -- position 0 is already
	// unlocked and should be left untouched by the resume catch-up.
	if err := s.SetChainStatus(chain.ID, "paused"); err != nil {
		t.Fatal(err)
	}
	if err := s.SetChainStatus(chain.ID, "active"); err != nil {
		t.Fatal(err)
	}

	after, err := s.GetChainTasks(chain.ID)
	if err != nil {
		t.Fatal(err)
	}
	if !after[0].DueDate.Equal(originalDueDate) {
		t.Errorf("DueDate = %v, want unchanged %v (resume catch-up should be a no-op when nothing was stuck)", after[0].DueDate, originalDueDate)
	}
}

func TestGetUndatedNativeTasks_ExcludesLockedChainTasks(t *testing.T) {
	s := newNativeTasksTestStore(t)

	chain, err := s.CreateChain("Track", chainTasks("Step 1", "Step 2", "Step 3"))
	if err != nil {
		t.Fatal(err)
	}
	_ = chain

	undated, err := s.GetUndatedNativeTasks()
	if err != nil {
		t.Fatalf("GetUndatedNativeTasks: %v", err)
	}
	for _, task := range undated {
		if task.ChainID != "" && !task.ChainUnlocked {
			t.Errorf("locked chain task %q leaked into GetUndatedNativeTasks", task.ID)
		}
	}
}

func TestCreateChain_PersistsDescriptionAndPriority(t *testing.T) {
	s := newNativeTasksTestStore(t)

	chain, err := s.CreateChain("Track", []models.ChainTaskInput{
		{Content: "Step 1", Description: "do the thing", Priority: 4},
		{Content: "Step 2"}, // no priority given -- should default to 1
	})
	if err != nil {
		t.Fatal(err)
	}
	tasks, err := s.GetChainTasks(chain.ID)
	if err != nil {
		t.Fatal(err)
	}
	if tasks[0].Description != "do the thing" || tasks[0].Priority != 4 {
		t.Errorf("tasks[0] = %+v, want description=%q priority=4", tasks[0], "do the thing")
	}
	if tasks[1].Priority != 1 {
		t.Errorf("tasks[1].Priority = %d, want default of 1", tasks[1].Priority)
	}
}

func TestGetChain_UnknownID_ReturnsErrNotFound(t *testing.T) {
	s := newNativeTasksTestStore(t)

	if _, err := s.GetChain("does-not-exist"); err != ErrNativeTaskNotFound {
		t.Errorf("err = %v, want ErrNativeTaskNotFound", err)
	}
}