package services

import (
	"testing"

	"github.com/go-playground/validator/v10"

	"github.com/breakpilot/school-service/internal/models"
)

// validate is a singleton used to exercise the same struct tags Gin uses for
// request validation. The DB tests live in integration tests against a real
// database; this test pins the contract for the request DTOs.
var validate = func() *validator.Validate {
	v := validator.New()
	v.SetTagName("binding")
	return v
}()

func TestNewTimetableService_Constructs(t *testing.T) {
	s := NewTimetableService(nil)
	if s == nil {
		t.Fatal("expected non-nil service")
	}
}

func TestCreateTimetableClassRequest_Validation(t *testing.T) {
	tests := []struct {
		name    string
		req     models.CreateTimetableClassRequest
		wantErr bool
	}{
		{"valid", models.CreateTimetableClassRequest{Name: "5a", GradeLevel: 5, StudentCount: 24}, false},
		{"missing name", models.CreateTimetableClassRequest{GradeLevel: 5}, true},
		{"grade too low", models.CreateTimetableClassRequest{Name: "0a", GradeLevel: 0}, true},
		{"grade too high", models.CreateTimetableClassRequest{Name: "14a", GradeLevel: 14}, true},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			err := validate.Struct(tt.req)
			if (err != nil) != tt.wantErr {
				t.Errorf("got err=%v, wantErr=%v", err, tt.wantErr)
			}
		})
	}
}

func TestCreateTimetablePeriodRequest_Validation(t *testing.T) {
	tests := []struct {
		name    string
		req     models.CreateTimetablePeriodRequest
		wantErr bool
	}{
		{"valid monday first", models.CreateTimetablePeriodRequest{DayOfWeek: 1, PeriodIndex: 1, StartTime: "08:00", EndTime: "08:45"}, false},
		{"day too low", models.CreateTimetablePeriodRequest{DayOfWeek: 0, PeriodIndex: 1, StartTime: "08:00", EndTime: "08:45"}, true},
		{"day too high", models.CreateTimetablePeriodRequest{DayOfWeek: 8, PeriodIndex: 1, StartTime: "08:00", EndTime: "08:45"}, true},
		{"missing times", models.CreateTimetablePeriodRequest{DayOfWeek: 1, PeriodIndex: 1}, true},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			err := validate.Struct(tt.req)
			if (err != nil) != tt.wantErr {
				t.Errorf("got err=%v, wantErr=%v", err, tt.wantErr)
			}
		})
	}
}

func TestCreateTimetableTeacherRequest_Validation(t *testing.T) {
	tests := []struct {
		name    string
		req     models.CreateTimetableTeacherRequest
		wantErr bool
	}{
		{"valid full-time", models.CreateTimetableTeacherRequest{FirstName: "Anna", LastName: "Schmidt", ShortCode: "SCH", EmploymentPercentage: 100, MaxHoursWeek: 28}, false},
		{"valid part-time", models.CreateTimetableTeacherRequest{FirstName: "Bea", LastName: "Mueller", ShortCode: "MUE", EmploymentPercentage: 50, MaxHoursWeek: 14}, false},
		{"missing names", models.CreateTimetableTeacherRequest{ShortCode: "XX"}, true},
		{"employment above 100", models.CreateTimetableTeacherRequest{FirstName: "X", LastName: "Y", ShortCode: "Z", EmploymentPercentage: 150}, true},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			err := validate.Struct(tt.req)
			if (err != nil) != tt.wantErr {
				t.Errorf("got err=%v, wantErr=%v", err, tt.wantErr)
			}
		})
	}
}

func TestCreateTimetableCurriculumRequest_Validation(t *testing.T) {
	tests := []struct {
		name    string
		req     models.CreateTimetableCurriculumRequest
		wantErr bool
	}{
		{"valid", models.CreateTimetableCurriculumRequest{ClassID: "00000000-0000-0000-0000-000000000001", SubjectID: "00000000-0000-0000-0000-000000000002", WeeklyHours: 4}, false},
		{"non-uuid class", models.CreateTimetableCurriculumRequest{ClassID: "not-a-uuid", SubjectID: "00000000-0000-0000-0000-000000000002", WeeklyHours: 4}, true},
		{"hours below 1", models.CreateTimetableCurriculumRequest{ClassID: "00000000-0000-0000-0000-000000000001", SubjectID: "00000000-0000-0000-0000-000000000002", WeeklyHours: 0}, true},
		{"hours above 10", models.CreateTimetableCurriculumRequest{ClassID: "00000000-0000-0000-0000-000000000001", SubjectID: "00000000-0000-0000-0000-000000000002", WeeklyHours: 11}, true},
	}
	for _, tt := range tests {
		t.Run(tt.name, func(t *testing.T) {
			err := validate.Struct(tt.req)
			if (err != nil) != tt.wantErr {
				t.Errorf("got err=%v, wantErr=%v", err, tt.wantErr)
			}
		})
	}
}