package sqlite

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

	"github.com/steveyegge/beads/internal/types"
	_ "modernc.org/sqlite"
)

func setupTestDB(t *testing.T) (*SQLiteStorage, func()) {
	t.Helper()

	// Create temporary directory
	tmpDir, err := os.MkdirTemp("", "beads-test-*")
	if err != nil {
		t.Fatalf("failed to create temp dir: %v", err)
	}

	dbPath := filepath.Join(tmpDir, "test.db")
	store, err := New(dbPath)
	if err != nil {
		os.RemoveAll(tmpDir)
		t.Fatalf("failed to create storage: %v", err)
	}

	cleanup := func() {
		store.Close()
		os.RemoveAll(tmpDir)
	}

	return store, cleanup
}

func TestCreateIssue(t *testing.T) {
	store, cleanup := setupTestDB(t)
	defer cleanup()

	ctx := context.Background()
	issue := &types.Issue{
		Title:       "Test issue",
		Description: "Test description",
		Status:      types.StatusOpen,
		Priority:    1,
		IssueType:   types.TypeTask,
	}

	err := store.CreateIssue(ctx, issue, "test-user")
	if err != nil {
		t.Fatalf("CreateIssue failed: %v", err)
	}

	if issue.ID == "" {
		t.Error("Issue ID should be set")
	}

	if !issue.CreatedAt.After(time.Time{}) {
		t.Error("CreatedAt should be set")
	}

	if !issue.UpdatedAt.After(time.Time{}) {
		t.Error("UpdatedAt should be set")
	}
}

func TestCreateIssueValidation(t *testing.T) {
	store, cleanup := setupTestDB(t)
	defer cleanup()

	ctx := context.Background()

	tests := []struct {
		name    string
		issue   *types.Issue
		wantErr bool
	}{
		{
			name: "valid issue",
			issue: &types.Issue{
				Title:     "Valid",
				Status:    types.StatusOpen,
				Priority:  2,
				IssueType: types.TypeTask,
			},
			wantErr: false,
		},
		{
			name: "missing title",
			issue: &types.Issue{
				Status:    types.StatusOpen,
				Priority:  2,
				IssueType: types.TypeTask,
			},
			wantErr: true,
		},
		{
			name: "invalid priority",
			issue: &types.Issue{
				Title:     "Test",
				Status:    types.StatusOpen,
				Priority:  10,
				IssueType: types.TypeTask,
			},
			wantErr: true,
		},
		{
			name: "invalid status",
			issue: &types.Issue{
				Title:     "Test",
				Status:    "invalid",
				Priority:  2,
				IssueType: types.TypeTask,
			},
			wantErr: true,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			err := store.CreateIssue(ctx, tt.issue, "test-user")
			if (err != nil) != tt.wantErr {
				t.Errorf("CreateIssue() error = %v, wantErr %v", err, tt.wantErr)
			}
		})
	}
}

func TestGetIssue(t *testing.T) {
	store, cleanup := setupTestDB(t)
	defer cleanup()

	ctx := context.Background()
	original := &types.Issue{
		Title:              "Test issue",
		Description:        "Description",
		Design:             "Design notes",
		AcceptanceCriteria: "Acceptance",
		Notes:              "Notes",
		Status:             types.StatusOpen,
		Priority:           1,
		IssueType:          types.TypeFeature,
		Assignee:           "alice",
	}

	err := store.CreateIssue(ctx, original, "test-user")
	if err != nil {
		t.Fatalf("CreateIssue failed: %v", err)
	}

	// Retrieve the issue
	retrieved, err := store.GetIssue(ctx, original.ID)
	if err != nil {
		t.Fatalf("GetIssue failed: %v", err)
	}

	if retrieved == nil {
		t.Fatal("GetIssue returned nil")
	}

	if retrieved.ID != original.ID {
		t.Errorf("ID mismatch: got %v, want %v", retrieved.ID, original.ID)
	}

	if retrieved.Title != original.Title {
		t.Errorf("Title mismatch: got %v, want %v", retrieved.Title, original.Title)
	}

	if retrieved.Description != original.Description {
		t.Errorf("Description mismatch: got %v, want %v", retrieved.Description, original.Description)
	}

	if retrieved.Assignee != original.Assignee {
		t.Errorf("Assignee mismatch: got %v, want %v", retrieved.Assignee, original.Assignee)
	}
}

func TestGetIssueNotFound(t *testing.T) {
	store, cleanup := setupTestDB(t)
	defer cleanup()

	ctx := context.Background()
	issue, err := store.GetIssue(ctx, "bd-999")
	if err != nil {
		t.Fatalf("GetIssue failed: %v", err)
	}

	if issue != nil {
		t.Errorf("Expected nil for non-existent issue, got %v", issue)
	}
}

func TestUpdateIssue(t *testing.T) {
	store, cleanup := setupTestDB(t)
	defer cleanup()

	ctx := context.Background()
	issue := &types.Issue{
		Title:     "Original",
		Status:    types.StatusOpen,
		Priority:  2,
		IssueType: types.TypeTask,
	}

	err := store.CreateIssue(ctx, issue, "test-user")
	if err != nil {
		t.Fatalf("CreateIssue failed: %v", err)
	}

	// Update the issue
	updates := map[string]interface{}{
		"title":    "Updated",
		"status":   string(types.StatusInProgress),
		"priority": 1,
		"assignee": "bob",
	}

	err = store.UpdateIssue(ctx, issue.ID, updates, "test-user")
	if err != nil {
		t.Fatalf("UpdateIssue failed: %v", err)
	}

	// Verify updates
	updated, err := store.GetIssue(ctx, issue.ID)
	if err != nil {
		t.Fatalf("GetIssue failed: %v", err)
	}

	if updated.Title != "Updated" {
		t.Errorf("Title not updated: got %v, want Updated", updated.Title)
	}

	if updated.Status != types.StatusInProgress {
		t.Errorf("Status not updated: got %v, want %v", updated.Status, types.StatusInProgress)
	}

	if updated.Priority != 1 {
		t.Errorf("Priority not updated: got %v, want 1", updated.Priority)
	}

	if updated.Assignee != "bob" {
		t.Errorf("Assignee not updated: got %v, want bob", updated.Assignee)
	}
}

func TestCloseIssue(t *testing.T) {
	store, cleanup := setupTestDB(t)
	defer cleanup()

	ctx := context.Background()
	issue := &types.Issue{
		Title:     "Test",
		Status:    types.StatusOpen,
		Priority:  2,
		IssueType: types.TypeTask,
	}

	err := store.CreateIssue(ctx, issue, "test-user")
	if err != nil {
		t.Fatalf("CreateIssue failed: %v", err)
	}

	err = store.CloseIssue(ctx, issue.ID, "Done", "test-user")
	if err != nil {
		t.Fatalf("CloseIssue failed: %v", err)
	}

	// Verify closure
	closed, err := store.GetIssue(ctx, issue.ID)
	if err != nil {
		t.Fatalf("GetIssue failed: %v", err)
	}

	if closed.Status != types.StatusClosed {
		t.Errorf("Status not closed: got %v, want %v", closed.Status, types.StatusClosed)
	}

	if closed.ClosedAt == nil {
		t.Error("ClosedAt should be set")
	}
}

func TestSearchIssues(t *testing.T) {
	store, cleanup := setupTestDB(t)
	defer cleanup()

	ctx := context.Background()

	// Create test issues
	issues := []*types.Issue{
		{Title: "Bug in login", Status: types.StatusOpen, Priority: 0, IssueType: types.TypeBug},
		{Title: "Feature request", Status: types.StatusOpen, Priority: 2, IssueType: types.TypeFeature},
		{Title: "Another bug", Status: types.StatusClosed, Priority: 1, IssueType: types.TypeBug},
	}

	for _, issue := range issues {
		err := store.CreateIssue(ctx, issue, "test-user")
		if err != nil {
			t.Fatalf("CreateIssue failed: %v", err)
		}
	}

	// Test query search
	results, err := store.SearchIssues(ctx, "bug", types.IssueFilter{})
	if err != nil {
		t.Fatalf("SearchIssues failed: %v", err)
	}

	if len(results) != 2 {
		t.Errorf("Expected 2 results, got %d", len(results))
	}

	// Test status filter
	openStatus := types.StatusOpen
	results, err = store.SearchIssues(ctx, "", types.IssueFilter{Status: &openStatus})
	if err != nil {
		t.Fatalf("SearchIssues failed: %v", err)
	}

	if len(results) != 2 {
		t.Errorf("Expected 2 open issues, got %d", len(results))
	}

	// Test type filter
	bugType := types.TypeBug
	results, err = store.SearchIssues(ctx, "", types.IssueFilter{IssueType: &bugType})
	if err != nil {
		t.Fatalf("SearchIssues failed: %v", err)
	}

	if len(results) != 2 {
		t.Errorf("Expected 2 bugs, got %d", len(results))
	}

	// Test priority filter (P0)
	priority0 := 0
	results, err = store.SearchIssues(ctx, "", types.IssueFilter{Priority: &priority0})
	if err != nil {
		t.Fatalf("SearchIssues failed: %v", err)
	}

	if len(results) != 1 {
		t.Errorf("Expected 1 P0 issue, got %d", len(results))
	}
}

func TestGetStatistics(t *testing.T) {
	store, cleanup := setupTestDB(t)
	defer cleanup()

	ctx := context.Background()

	// Test statistics on empty database (regression test for NULL handling)
	stats, err := store.GetStatistics(ctx)
	if err != nil {
		t.Fatalf("GetStatistics failed on empty database: %v", err)
	}

	if stats.TotalIssues != 0 {
		t.Errorf("Expected 0 total issues, got %d", stats.TotalIssues)
	}
	if stats.OpenIssues != 0 {
		t.Errorf("Expected 0 open issues, got %d", stats.OpenIssues)
	}
	if stats.InProgressIssues != 0 {
		t.Errorf("Expected 0 in-progress issues, got %d", stats.InProgressIssues)
	}
	if stats.ClosedIssues != 0 {
		t.Errorf("Expected 0 closed issues, got %d", stats.ClosedIssues)
	}

	// Create some issues to verify statistics work with data
	issues := []*types.Issue{
		{Title: "Open task", Status: types.StatusOpen, Priority: 1, IssueType: types.TypeTask},
		{Title: "In progress task", Status: types.StatusInProgress, Priority: 1, IssueType: types.TypeTask},
		{Title: "Closed task", Status: types.StatusClosed, Priority: 1, IssueType: types.TypeTask},
		{Title: "Another open task", Status: types.StatusOpen, Priority: 2, IssueType: types.TypeTask},
	}

	for _, issue := range issues {
		err := store.CreateIssue(ctx, issue, "test-user")
		if err != nil {
			t.Fatalf("CreateIssue failed: %v", err)
		}
		// Close the one that should be closed
		if issue.Title == "Closed task" {
			err = store.CloseIssue(ctx, issue.ID, "Done", "test-user")
			if err != nil {
				t.Fatalf("CloseIssue failed: %v", err)
			}
		}
	}

	// Get statistics with data
	stats, err = store.GetStatistics(ctx)
	if err != nil {
		t.Fatalf("GetStatistics failed with data: %v", err)
	}

	if stats.TotalIssues != 4 {
		t.Errorf("Expected 4 total issues, got %d", stats.TotalIssues)
	}
	if stats.OpenIssues != 2 {
		t.Errorf("Expected 2 open issues, got %d", stats.OpenIssues)
	}
	if stats.InProgressIssues != 1 {
		t.Errorf("Expected 1 in-progress issue, got %d", stats.InProgressIssues)
	}
	if stats.ClosedIssues != 1 {
		t.Errorf("Expected 1 closed issue, got %d", stats.ClosedIssues)
	}
	if stats.ReadyIssues != 2 {
		t.Errorf("Expected 2 ready issues (open with no blockers), got %d", stats.ReadyIssues)
	}
}

// Note: High-concurrency stress tests were removed as the pure Go SQLite driver
// (modernc.org/sqlite) can experience "database is locked" errors under extreme
// parallel load (100+ simultaneous operations). This is a known limitation and
// does not affect normal usage where WAL mode handles typical concurrent operations.
// For very high concurrency needs, consider using CGO-enabled sqlite3 driver or PostgreSQL.

// TestParallelIssueCreation verifies that parallel issue creation doesn't cause ID collisions
// This is a regression test for bd-89 (GH-6) where race conditions in ID generation caused
// UNIQUE constraint failures when creating issues rapidly in parallel.
func TestParallelIssueCreation(t *testing.T) {
	store, cleanup := setupTestDB(t)
	defer cleanup()

	ctx := context.Background()
	const numIssues = 20

	// Create issues in parallel using goroutines
	errors := make(chan error, numIssues)
	ids := make(chan string, numIssues)

	for i := 0; i < numIssues; i++ {
		go func(num int) {
			issue := &types.Issue{
				Title:     "Parallel test issue",
				Status:    types.StatusOpen,
				Priority:  2,
				IssueType: types.TypeTask,
			}
			err := store.CreateIssue(ctx, issue, "test-user")
			if err != nil {
				errors <- err
				return
			}
			ids <- issue.ID
			errors <- nil
		}(i)
	}

	// Collect results
	var collectedIDs []string
	var failureCount int
	for i := 0; i < numIssues; i++ {
		if err := <-errors; err != nil {
			t.Errorf("CreateIssue failed in parallel test: %v", err)
			failureCount++
		}
	}

	close(ids)
	for id := range ids {
		collectedIDs = append(collectedIDs, id)
	}

	// Verify no failures occurred
	if failureCount > 0 {
		t.Fatalf("Expected 0 failures, got %d", failureCount)
	}

	// Verify we got the expected number of IDs
	if len(collectedIDs) != numIssues {
		t.Fatalf("Expected %d IDs, got %d", numIssues, len(collectedIDs))
	}

	// Verify all IDs are unique (no duplicates from race conditions)
	seen := make(map[string]bool)
	for _, id := range collectedIDs {
		if seen[id] {
			t.Errorf("Duplicate ID detected: %s", id)
		}
		seen[id] = true
	}

	// Verify all issues can be retrieved (they actually exist in the database)
	for _, id := range collectedIDs {
		issue, err := store.GetIssue(ctx, id)
		if err != nil {
			t.Errorf("Failed to retrieve issue %s: %v", id, err)
		}
		if issue == nil {
			t.Errorf("Issue %s not found in database", id)
		}
	}
}