package api

import (
	"bytes"
	"database/sql"
	"encoding/json"
	"errors"
	"net/http"
	"net/http/httptest"
	"testing"
	"time"

	"training-tracker/internal/models"
)

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

	tests := []struct {
		name       string
		mock       *mockPlanRepo
		wantStatus int
		wantLen    int
	}{
		{
			name:       "empty list",
			mock:       &mockPlanRepo{plans: nil},
			wantStatus: http.StatusOK,
			wantLen:    0,
		},
		{
			name: "multiple plans",
			mock: &mockPlanRepo{
				plans: []models.TrainingPlan{
					{ID: 1, Name: "Push Day"},
					{ID: 2, Name: "Pull Day"},
					{ID: 3, Name: "Leg Day"},
				},
			},
			wantStatus: http.StatusOK,
			wantLen:    3,
		},
		{
			name:       "repository error",
			mock:       &mockPlanRepo{err: errors.New("db error")},
			wantStatus: http.StatusInternalServerError,
			wantLen:    0,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()

			handler := NewPlanHandler(tt.mock)
			req := httptest.NewRequest(http.MethodGet, "/api/plans", nil)
			rec := httptest.NewRecorder()

			handler.ServeHTTP(rec, req)

			if rec.Code != tt.wantStatus {
				t.Errorf("status = %d, want %d", rec.Code, tt.wantStatus)
			}

			if tt.wantStatus == http.StatusOK {
				var plans []models.TrainingPlan
				if err := json.NewDecoder(rec.Body).Decode(&plans); err != nil {
					t.Fatalf("failed to decode response: %v", err)
				}
				if len(plans) != tt.wantLen {
					t.Errorf("len = %d, want %d", len(plans), tt.wantLen)
				}
			}
		})
	}
}

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

	now := time.Now()
	tests := []struct {
		name       string
		url        string
		mock       *mockPlanRepo
		wantStatus int
		wantName   string
	}{
		{
			name: "found",
			url:  "/api/plans/1",
			mock: &mockPlanRepo{
				plan: &models.TrainingPlan{
					ID:          1,
					Name:        "Full Body",
					Description: "Complete workout",
					CreatedAt:   now,
				},
			},
			wantStatus: http.StatusOK,
			wantName:   "Full Body",
		},
		{
			name: "found with exercises",
			url:  "/api/plans/2",
			mock: &mockPlanRepo{
				plan: &models.TrainingPlan{
					ID:   2,
					Name: "Upper Body",
					Exercises: []models.PlanExercise{
						{ID: 1, PlanID: 2, ExerciseID: 1, Sets: 3, Reps: 10},
						{ID: 2, PlanID: 2, ExerciseID: 2, Sets: 4, Reps: 8},
					},
					CreatedAt: now,
				},
			},
			wantStatus: http.StatusOK,
			wantName:   "Upper Body",
		},
		{
			name:       "not found",
			url:        "/api/plans/999",
			mock:       &mockPlanRepo{plan: nil},
			wantStatus: http.StatusNotFound,
		},
		{
			name:       "repository error",
			url:        "/api/plans/1",
			mock:       &mockPlanRepo{err: errors.New("db error")},
			wantStatus: http.StatusInternalServerError,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()

			handler := NewPlanHandler(tt.mock)
			req := httptest.NewRequest(http.MethodGet, tt.url, nil)
			rec := httptest.NewRecorder()

			handler.ServeHTTP(rec, req)

			if rec.Code != tt.wantStatus {
				t.Errorf("status = %d, want %d", rec.Code, tt.wantStatus)
			}

			if tt.wantStatus == http.StatusOK {
				var plan models.TrainingPlan
				if err := json.NewDecoder(rec.Body).Decode(&plan); err != nil {
					t.Fatalf("failed to decode response: %v", err)
				}
				if plan.Name != tt.wantName {
					t.Errorf("name = %q, want %q", plan.Name, tt.wantName)
				}
			}
		})
	}
}

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

	now := time.Now()
	tests := []struct {
		name       string
		body       string
		mock       *mockPlanRepo
		wantStatus int
	}{
		{
			name: "valid plan without exercises",
			body: `{"name":"Beginner Plan","description":"A simple plan"}`,
			mock: &mockPlanRepo{
				plan: &models.TrainingPlan{
					ID:          1,
					Name:        "Beginner Plan",
					Description: "A simple plan",
					CreatedAt:   now,
				},
			},
			wantStatus: http.StatusCreated,
		},
		{
			name: "valid plan with exercises",
			body: `{"name":"Advanced Plan","exercises":[{"exercise_id":1,"sets":3,"reps":10,"order":1}]}`,
			mock: &mockPlanRepo{
				plan: &models.TrainingPlan{
					ID:   2,
					Name: "Advanced Plan",
					Exercises: []models.PlanExercise{
						{ID: 1, PlanID: 2, ExerciseID: 1, Sets: 3, Reps: 10, Order: 1},
					},
					CreatedAt: now,
				},
			},
			wantStatus: http.StatusCreated,
		},
		{
			name:       "missing name",
			body:       `{"description":"No name"}`,
			mock:       &mockPlanRepo{},
			wantStatus: http.StatusBadRequest,
		},
		{
			name:       "empty name",
			body:       `{"name":""}`,
			mock:       &mockPlanRepo{},
			wantStatus: http.StatusBadRequest,
		},
		{
			name:       "invalid JSON",
			body:       `{invalid}`,
			mock:       &mockPlanRepo{},
			wantStatus: http.StatusBadRequest,
		},
		{
			name:       "repository error",
			body:       `{"name":"Test Plan"}`,
			mock:       &mockPlanRepo{err: errors.New("db error")},
			wantStatus: http.StatusInternalServerError,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()

			handler := NewPlanHandler(tt.mock)
			req := httptest.NewRequest(http.MethodPost, "/api/plans", bytes.NewBufferString(tt.body))
			req.Header.Set("Content-Type", "application/json")
			rec := httptest.NewRecorder()

			handler.ServeHTTP(rec, req)

			if rec.Code != tt.wantStatus {
				t.Errorf("status = %d, want %d", rec.Code, tt.wantStatus)
			}
		})
	}
}

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

	now := time.Now()
	tests := []struct {
		name       string
		url        string
		body       string
		mock       *mockPlanRepo
		wantStatus int
	}{
		{
			name: "valid update",
			url:  "/api/plans/1",
			body: `{"name":"Updated Plan","description":"New description"}`,
			mock: &mockPlanRepo{
				plan: &models.TrainingPlan{
					ID:          1,
					Name:        "Updated Plan",
					Description: "New description",
					CreatedAt:   now,
				},
			},
			wantStatus: http.StatusOK,
		},
		{
			name: "update with exercises",
			url:  "/api/plans/1",
			body: `{"name":"Plan with Exercises","exercises":[{"exercise_id":1,"sets":4,"reps":12,"order":1}]}`,
			mock: &mockPlanRepo{
				plan: &models.TrainingPlan{
					ID:   1,
					Name: "Plan with Exercises",
					Exercises: []models.PlanExercise{
						{ID: 1, PlanID: 1, ExerciseID: 1, Sets: 4, Reps: 12, Order: 1},
					},
					CreatedAt: now,
				},
			},
			wantStatus: http.StatusOK,
		},
		{
			name:       "not found",
			url:        "/api/plans/999",
			body:       `{"name":"Test"}`,
			mock:       &mockPlanRepo{plan: nil},
			wantStatus: http.StatusNotFound,
		},
		{
			name:       "missing name",
			url:        "/api/plans/1",
			body:       `{"description":"No name"}`,
			mock:       &mockPlanRepo{},
			wantStatus: http.StatusBadRequest,
		},
		{
			name:       "no ID in URL",
			url:        "/api/plans/",
			body:       `{"name":"Test"}`,
			mock:       &mockPlanRepo{},
			wantStatus: http.StatusBadRequest,
		},
		{
			name:       "repository error",
			url:        "/api/plans/1",
			body:       `{"name":"Test"}`,
			mock:       &mockPlanRepo{err: errors.New("db error")},
			wantStatus: http.StatusInternalServerError,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()

			handler := NewPlanHandler(tt.mock)
			req := httptest.NewRequest(http.MethodPut, tt.url, bytes.NewBufferString(tt.body))
			req.Header.Set("Content-Type", "application/json")
			rec := httptest.NewRecorder()

			handler.ServeHTTP(rec, req)

			if rec.Code != tt.wantStatus {
				t.Errorf("status = %d, want %d", rec.Code, tt.wantStatus)
			}
		})
	}
}

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

	tests := []struct {
		name       string
		url        string
		mock       *mockPlanRepo
		wantStatus int
	}{
		{
			name:       "successful delete",
			url:        "/api/plans/1",
			mock:       &mockPlanRepo{deleteErr: nil},
			wantStatus: http.StatusNoContent,
		},
		{
			name:       "not found",
			url:        "/api/plans/999",
			mock:       &mockPlanRepo{deleteErr: sql.ErrNoRows},
			wantStatus: http.StatusNotFound,
		},
		{
			name:       "no ID in URL",
			url:        "/api/plans/",
			mock:       &mockPlanRepo{},
			wantStatus: http.StatusBadRequest,
		},
		{
			name:       "repository error",
			url:        "/api/plans/1",
			mock:       &mockPlanRepo{deleteErr: errors.New("db error")},
			wantStatus: http.StatusInternalServerError,
		},
	}

	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			t.Parallel()

			handler := NewPlanHandler(tt.mock)
			req := httptest.NewRequest(http.MethodDelete, tt.url, nil)
			rec := httptest.NewRecorder()

			handler.ServeHTTP(rec, req)

			if rec.Code != tt.wantStatus {
				t.Errorf("status = %d, want %d", rec.Code, tt.wantStatus)
			}
		})
	}
}

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

	handler := NewPlanHandler(&mockPlanRepo{})
	req := httptest.NewRequest(http.MethodPatch, "/api/plans/1", nil)
	rec := httptest.NewRecorder()

	handler.ServeHTTP(rec, req)

	if rec.Code != http.StatusMethodNotAllowed {
		t.Errorf("status = %d, want %d", rec.Code, http.StatusMethodNotAllowed)
	}
}