package handlers

import (
	"Yimaru-Backend/internal/domain"
	"fmt"

	"github.com/gofiber/fiber/v2"
)

func (h *Handler) learnerHasLearnEnglishSubscription(c *fiber.Ctx) (bool, error) {
	return h.learnerHasSubscriptionCategory(c, domain.SubscriptionCategoryLearnEnglish)
}

func (h *Handler) ensureLearnerPremiumContentAccess(c *fiber.Ctx, effectiveTier domain.ContentAccessTier, category domain.SubscriptionCategory) error {
	role, _ := c.Locals("role").(domain.Role)
	if !role.IsCustomerLearnerRole() || domain.CategorySubscriptionGateDisabled {
		return nil
	}
	if !effectiveTier.RequiresSubscription() {
		return nil
	}
	active, err := h.learnerHasSubscriptionCategory(c, category)
	if err != nil {
		return c.Status(fiber.StatusInternalServerError).JSON(domain.ErrorResponse{
			Message: fmt.Sprintf("Failed to verify %s subscription", category),
			Error:   err.Error(),
		})
	}
	if !active {
		return c.Status(fiber.StatusForbidden).JSON(domain.ErrorResponse{
			Message: fmt.Sprintf("An active %s subscription is required", humanizeSubscriptionCategory(category)),
		})
	}
	return nil
}

func applyProgramEffectiveAccessTier(p *domain.Program) {
	p.EffectiveAccessTier = p.AccessTier
}

func applyCourseEffectiveAccessTier(course *domain.Course, program domain.Program) {
	course.EffectiveAccessTier = domain.EffectiveContentAccessTier(program.AccessTier, course.AccessTier)
}

func applyModuleEffectiveAccessTier(module *domain.Module, program domain.Program, course domain.Course) {
	module.EffectiveAccessTier = domain.EffectiveContentAccessTier(program.AccessTier, course.AccessTier, module.AccessTier)
}

func applyLessonEffectiveAccessTier(lesson *domain.Lesson, program domain.Program, course domain.Course, module domain.Module) {
	lesson.EffectiveAccessTier = domain.EffectiveContentAccessTier(program.AccessTier, course.AccessTier, module.AccessTier, lesson.AccessTier)
}

func applyExamPrepCatalogCourseEffectiveAccessTier(cc *domain.ExamPrepCatalogCourse) {
	cc.EffectiveAccessTier = cc.AccessTier
}

func applyExamPrepUnitEffectiveAccessTier(unit *domain.ExamPrepUnit, catalogCourse domain.ExamPrepCatalogCourse) {
	unit.EffectiveAccessTier = domain.EffectiveContentAccessTier(catalogCourse.AccessTier, unit.AccessTier)
}

func applyExamPrepModuleEffectiveAccessTier(module *domain.ExamPrepModule, catalogCourse domain.ExamPrepCatalogCourse, unit domain.ExamPrepUnit) {
	module.EffectiveAccessTier = domain.EffectiveContentAccessTier(catalogCourse.AccessTier, unit.AccessTier, module.AccessTier)
}

func applyExamPrepLessonEffectiveAccessTier(lesson *domain.ExamPrepLesson, catalogCourse domain.ExamPrepCatalogCourse, unit domain.ExamPrepUnit, module domain.ExamPrepModule) {
	lesson.EffectiveAccessTier = domain.EffectiveContentAccessTier(catalogCourse.AccessTier, unit.AccessTier, module.AccessTier, lesson.AccessTier)
}

func learnerCanViewEffectiveTier(hasSubscription bool, effectiveTier domain.ContentAccessTier) bool {
	return !effectiveTier.RequiresSubscription() || hasSubscription
}

func filterProgramsForLearner(items []domain.Program, hasLearnEnglish bool) []domain.Program {
	filtered := make([]domain.Program, 0, len(items))
	for _, item := range items {
		applyProgramEffectiveAccessTier(&item)
		if learnerCanViewEffectiveTier(hasLearnEnglish, item.EffectiveAccessTier) {
			filtered = append(filtered, item)
		}
	}
	return filtered
}

func filterCoursesForLearner(items []domain.Course, program domain.Program, hasLearnEnglish bool) []domain.Course {
	filtered := make([]domain.Course, 0, len(items))
	for i := range items {
		applyCourseEffectiveAccessTier(&items[i], program)
		if learnerCanViewEffectiveTier(hasLearnEnglish, items[i].EffectiveAccessTier) {
			filtered = append(filtered, items[i])
		}
	}
	return filtered
}

func filterExamPrepCatalogCoursesForLearner(items []domain.ExamPrepCatalogCourse, hasIELTS, hasDuolingo bool) []domain.ExamPrepCatalogCourse {
	if domain.ExamPrepSubscriptionGateDisabled {
		out := make([]domain.ExamPrepCatalogCourse, 0, len(items))
		for _, item := range items {
			applyExamPrepCatalogCourseEffectiveAccessTier(&item)
			out = append(out, item)
		}
		return out
	}
	filtered := make([]domain.ExamPrepCatalogCourse, 0, len(items))
	for _, item := range items {
		applyExamPrepCatalogCourseEffectiveAccessTier(&item)
		if !item.EffectiveAccessTier.RequiresSubscription() {
			filtered = append(filtered, item)
			continue
		}
		switch domain.SubscriptionCategory(item.Category) {
		case domain.SubscriptionCategoryIELTS:
			if hasIELTS {
				filtered = append(filtered, item)
			}
		case domain.SubscriptionCategoryDuolingo:
			if hasDuolingo {
				filtered = append(filtered, item)
			}
		}
	}
	return filtered
}