package server

import (
	"encoding/json"
	"net/http"
	"net/http/httptest"
	"os"
	"path/filepath"
	"testing"

	"github.com/dal/kaos/internal/config"
)

const testTask1 = `# T01: Prvi task

**Agent:** coder
**Model:** Sonnet
**Zavisi od:** —

---

## Opis

Opis prvog taska.

---
`

const testTask2 = `# T08: HTTP server

**Agent:** coder
**Model:** Sonnet
**Zavisi od:** T07

---

## Opis

Implementacija HTTP servera.

---
`

func setupTestServer(t *testing.T) *Server {
	t.Helper()
	dir := t.TempDir()

	tasksDir := filepath.Join(dir, "TASKS")
	for _, folder := range []string{"backlog", "ready", "active", "review", "done", "reports"} {
		os.MkdirAll(filepath.Join(tasksDir, folder), 0755)
	}

	os.WriteFile(filepath.Join(tasksDir, "done", "T01.md"), []byte(testTask1), 0644)
	os.WriteFile(filepath.Join(tasksDir, "backlog", "T08.md"), []byte(testTask2), 0644)

	cfg := &config.Config{
		TasksDir:    tasksDir,
		ProjectPath: dir,
		Port:        "0",
	}

	return New(cfg)
}

func TestAPIGetTasks(t *testing.T) {
	srv := setupTestServer(t)

	req := httptest.NewRequest(http.MethodGet, "/api/tasks", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("expected 200, got %d: %s", w.Code, w.Body.String())
	}

	var tasks []taskResponse
	if err := json.Unmarshal(w.Body.Bytes(), &tasks); err != nil {
		t.Fatalf("invalid JSON: %v", err)
	}

	if len(tasks) != 2 {
		t.Fatalf("expected 2 tasks, got %d", len(tasks))
	}

	// Check that tasks have correct statuses
	statuses := map[string]string{}
	for _, task := range tasks {
		statuses[task.ID] = task.Status
	}
	if statuses["T01"] != "done" {
		t.Errorf("expected T01 status done, got %s", statuses["T01"])
	}
	if statuses["T08"] != "backlog" {
		t.Errorf("expected T08 status backlog, got %s", statuses["T08"])
	}
}

func TestAPIGetTask(t *testing.T) {
	srv := setupTestServer(t)

	req := httptest.NewRequest(http.MethodGet, "/api/task/T01", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("expected 200, got %d", w.Code)
	}

	var detail taskDetailResponse
	if err := json.Unmarshal(w.Body.Bytes(), &detail); err != nil {
		t.Fatalf("invalid JSON: %v", err)
	}

	if detail.ID != "T01" {
		t.Errorf("expected T01, got %s", detail.ID)
	}
	if detail.Content == "" {
		t.Error("expected non-empty content")
	}
}

func TestAPIGetTask_NotFound(t *testing.T) {
	srv := setupTestServer(t)

	req := httptest.NewRequest(http.MethodGet, "/api/task/T99", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	if w.Code != http.StatusNotFound {
		t.Fatalf("expected 404, got %d", w.Code)
	}
}

func TestAPIMoveTask(t *testing.T) {
	srv := setupTestServer(t)

	req := httptest.NewRequest(http.MethodPost, "/api/task/T08/move?to=ready", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("expected 200, got %d: %s", w.Code, w.Body.String())
	}

	// Verify file was moved
	if _, err := os.Stat(filepath.Join(srv.Config.TasksDir, "ready", "T08.md")); err != nil {
		t.Error("expected T08.md in ready/")
	}
	if _, err := os.Stat(filepath.Join(srv.Config.TasksDir, "backlog", "T08.md")); !os.IsNotExist(err) {
		t.Error("expected T08.md removed from backlog/")
	}
}

func TestAPIMoveTask_NotFound(t *testing.T) {
	srv := setupTestServer(t)

	req := httptest.NewRequest(http.MethodPost, "/api/task/T99/move?to=ready", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	if w.Code != http.StatusNotFound {
		t.Fatalf("expected 404, got %d", w.Code)
	}
}

func TestAPIMoveTask_InvalidFolder(t *testing.T) {
	srv := setupTestServer(t)

	req := httptest.NewRequest(http.MethodPost, "/api/task/T08/move?to=invalid", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	if w.Code != http.StatusBadRequest {
		t.Fatalf("expected 400, got %d", w.Code)
	}
}

func TestDashboardHTML(t *testing.T) {
	srv := setupTestServer(t)

	req := httptest.NewRequest(http.MethodGet, "/", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("expected 200, got %d", w.Code)
	}

	body := w.Body.String()
	if !containsStr(body, "KAOS Dashboard") {
		t.Error("expected 'KAOS Dashboard' in HTML")
	}
	if !containsStr(body, "T01") {
		t.Error("expected T01 in HTML")
	}
	if !containsStr(body, "T08") {
		t.Error("expected T08 in HTML")
	}
	if !containsStr(body, "BACKLOG") {
		t.Error("expected BACKLOG column in HTML")
	}
	if !containsStr(body, "DONE") {
		t.Error("expected DONE column in HTML")
	}
}

func TestTaskDetailHTML(t *testing.T) {
	srv := setupTestServer(t)

	req := httptest.NewRequest(http.MethodGet, "/task/T01", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("expected 200, got %d", w.Code)
	}

	body := w.Body.String()
	if !containsStr(body, "T01") {
		t.Error("expected T01 in detail HTML")
	}
	if !containsStr(body, "Prvi task") {
		t.Error("expected task title in detail HTML")
	}
}

func TestTaskDetailHTML_NotFound(t *testing.T) {
	srv := setupTestServer(t)

	req := httptest.NewRequest(http.MethodGet, "/task/T99", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	if w.Code != http.StatusNotFound {
		t.Fatalf("expected 404, got %d", w.Code)
	}
}

func TestHTMLMoveTask(t *testing.T) {
	srv := setupTestServer(t)

	req := httptest.NewRequest(http.MethodPost, "/task/T08/move?to=ready", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("expected 200, got %d: %s", w.Code, w.Body.String())
	}

	// Should return updated dashboard HTML
	body := w.Body.String()
	if !containsStr(body, "KAOS Dashboard") {
		t.Error("expected dashboard HTML after move")
	}
}

func TestDashboardHTML_HasAllColumns(t *testing.T) {
	srv := setupTestServer(t)

	req := httptest.NewRequest(http.MethodGet, "/", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	body := w.Body.String()
	for _, col := range []string{"BACKLOG", "READY", "ACTIVE", "REVIEW", "DONE"} {
		if !containsStr(body, col) {
			t.Errorf("expected %s column in dashboard", col)
		}
	}
}

func TestDashboardHTML_HasHTMXAttributes(t *testing.T) {
	srv := setupTestServer(t)

	req := httptest.NewRequest(http.MethodGet, "/", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	body := w.Body.String()
	if !containsStr(body, "hx-get") {
		t.Error("expected hx-get attributes in HTML")
	}
	if !containsStr(body, "hx-target") {
		t.Error("expected hx-target attributes in HTML")
	}
}

func TestDashboardHTML_TasksInCorrectColumns(t *testing.T) {
	srv := setupTestServer(t)

	req := httptest.NewRequest(http.MethodGet, "/", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	body := w.Body.String()
	// T01 should be in done column, T08 in backlog
	if !containsStr(body, `id="col-done"`) {
		t.Error("expected col-done in HTML")
	}
	if !containsStr(body, `id="col-backlog"`) {
		t.Error("expected col-backlog in HTML")
	}
}

func TestReport_Exists(t *testing.T) {
	srv := setupTestServer(t)

	// Create a report
	reportsDir := filepath.Join(srv.Config.TasksDir, "reports")
	os.MkdirAll(reportsDir, 0755)
	os.WriteFile(filepath.Join(reportsDir, "T01-report.md"), []byte("# T01 Report\nSve ok."), 0644)

	req := httptest.NewRequest(http.MethodGet, "/report/T01", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("expected 200, got %d", w.Code)
	}
	if !containsStr(w.Body.String(), "T01 Report") {
		t.Error("expected report content")
	}
}

func TestReport_NotFound(t *testing.T) {
	srv := setupTestServer(t)

	req := httptest.NewRequest(http.MethodGet, "/report/T99", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	if w.Code != http.StatusNotFound {
		t.Fatalf("expected 404, got %d", w.Code)
	}
}

func TestTaskDetail_HasMoveButtons(t *testing.T) {
	srv := setupTestServer(t)

	// T08 is in backlog, should have "Premesti u Ready" button
	req := httptest.NewRequest(http.MethodGet, "/task/T08", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("expected 200, got %d", w.Code)
	}

	body := w.Body.String()
	if !containsStr(body, "Ready") {
		t.Error("expected 'Ready' move button for backlog task")
	}
}

func TestAPIMoveTask_ForbiddenToActive(t *testing.T) {
	srv := setupTestServer(t)

	// Put T08 in ready first
	os.Rename(
		filepath.Join(srv.Config.TasksDir, "backlog", "T08.md"),
		filepath.Join(srv.Config.TasksDir, "ready", "T08.md"),
	)

	// Try to move ready → active (agent-only)
	req := httptest.NewRequest(http.MethodPost, "/api/task/T08/move?to=active", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	if w.Code != http.StatusForbidden {
		t.Fatalf("expected 403 for ready→active, got %d: %s", w.Code, w.Body.String())
	}
}

func TestAPIMoveTask_ForbiddenActiveToReview(t *testing.T) {
	srv := setupTestServer(t)

	// Put T08 in active
	os.Rename(
		filepath.Join(srv.Config.TasksDir, "backlog", "T08.md"),
		filepath.Join(srv.Config.TasksDir, "active", "T08.md"),
	)

	// Try to move active → review (agent-only)
	req := httptest.NewRequest(http.MethodPost, "/api/task/T08/move?to=review", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	if w.Code != http.StatusForbidden {
		t.Fatalf("expected 403 for active→review, got %d: %s", w.Code, w.Body.String())
	}
}

func TestAPIMoveTask_AllowedBacklogToReady(t *testing.T) {
	srv := setupTestServer(t)

	req := httptest.NewRequest(http.MethodPost, "/api/task/T08/move?to=ready", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("expected 200 for backlog→ready, got %d: %s", w.Code, w.Body.String())
	}
}

func TestAPIMoveTask_AllowedReviewToDone(t *testing.T) {
	srv := setupTestServer(t)

	// Put T08 in review
	os.Rename(
		filepath.Join(srv.Config.TasksDir, "backlog", "T08.md"),
		filepath.Join(srv.Config.TasksDir, "review", "T08.md"),
	)

	req := httptest.NewRequest(http.MethodPost, "/api/task/T08/move?to=done", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	if w.Code != http.StatusOK {
		t.Fatalf("expected 200 for review→done, got %d: %s", w.Code, w.Body.String())
	}
}

func TestDashboardHTML_HasSortableScript(t *testing.T) {
	srv := setupTestServer(t)

	req := httptest.NewRequest(http.MethodGet, "/", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	body := w.Body.String()
	if !containsStr(body, "sortable.min.js") {
		t.Error("expected sortable.min.js script tag")
	}
	if !containsStr(body, "initSortable") {
		t.Error("expected initSortable function")
	}
}

func TestDashboardHTML_HasDataFolderAttributes(t *testing.T) {
	srv := setupTestServer(t)

	req := httptest.NewRequest(http.MethodGet, "/", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	body := w.Body.String()
	if !containsStr(body, `data-folder="backlog"`) {
		t.Error("expected data-folder attribute on column-tasks")
	}
	if !containsStr(body, `data-folder="ready"`) {
		t.Error("expected data-folder=ready attribute")
	}
}

func TestIsMoveAllowed(t *testing.T) {
	tests := []struct {
		from, to string
		allowed  bool
	}{
		{"backlog", "ready", true},
		{"ready", "backlog", true},
		{"review", "done", true},
		{"review", "ready", true},
		{"done", "review", true},
		{"ready", "active", false},
		{"active", "review", false},
		{"backlog", "done", false},
		{"backlog", "active", false},
		{"done", "backlog", false},
		{"ready", "ready", false},
	}

	for _, tt := range tests {
		got := isMoveAllowed(tt.from, tt.to)
		if got != tt.allowed {
			t.Errorf("isMoveAllowed(%s, %s) = %v, want %v", tt.from, tt.to, got, tt.allowed)
		}
	}
}

func TestNoCacheHeaders(t *testing.T) {
	srv := setupTestServer(t)

	// Dynamic route should have no-cache headers
	req := httptest.NewRequest(http.MethodGet, "/", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	cc := w.Header().Get("Cache-Control")
	if !containsStr(cc, "no-store") {
		t.Errorf("expected Cache-Control no-store on dashboard, got %q", cc)
	}

	// API route should also have no-cache headers
	req2 := httptest.NewRequest(http.MethodGet, "/api/tasks", nil)
	w2 := httptest.NewRecorder()
	srv.Router.ServeHTTP(w2, req2)

	cc2 := w2.Header().Get("Cache-Control")
	if !containsStr(cc2, "no-store") {
		t.Errorf("expected Cache-Control no-store on API, got %q", cc2)
	}
}

func TestDashboardReflectsDiskChanges(t *testing.T) {
	srv := setupTestServer(t)

	// Initial state: T08 in backlog
	req := httptest.NewRequest(http.MethodGet, "/api/tasks", nil)
	w := httptest.NewRecorder()
	srv.Router.ServeHTTP(w, req)

	var tasks1 []taskResponse
	json.Unmarshal(w.Body.Bytes(), &tasks1)

	found := false
	for _, task := range tasks1 {
		if task.ID == "T08" && task.Status == "backlog" {
			found = true
		}
	}
	if !found {
		t.Fatal("expected T08 in backlog initially")
	}

	// Move file on disk (simulating external change)
	os.Rename(
		filepath.Join(srv.Config.TasksDir, "backlog", "T08.md"),
		filepath.Join(srv.Config.TasksDir, "ready", "T08.md"),
	)

	// Second request should reflect the change without server restart
	req2 := httptest.NewRequest(http.MethodGet, "/api/tasks", nil)
	w2 := httptest.NewRecorder()
	srv.Router.ServeHTTP(w2, req2)

	var tasks2 []taskResponse
	json.Unmarshal(w2.Body.Bytes(), &tasks2)

	found = false
	for _, task := range tasks2 {
		if task.ID == "T08" && task.Status == "ready" {
			found = true
		}
	}
	if !found {
		t.Fatal("expected T08 in ready after disk move — server did not read fresh state")
	}
}

func containsStr(s, substr string) bool {
	return len(s) >= len(substr) && findStr(s, substr)
}

func findStr(s, substr string) bool {
	for i := 0; i <= len(s)-len(substr); i++ {
		if s[i:i+len(substr)] == substr {
			return true
		}
	}
	return false
}