package growth

import (
	"fmt"
	"slices"
	"strings"
	"time"
)

const officialCalendarSource = "https://calendar.ut.ac.ir/"
const curatedCommercialSource = "CURATED_COMMERCIAL_1405_V1"
const officialCalendarVersion = "IR_OFFICIAL_1404_1405_REVIEWED_2026-08-21"

var importedMerchantCategories = []string{
	"ارائه دهنده خدمات اینترنت",
	"مراکز آموزشی مجازی",
	"کیف و کفش فروشی",
	"خدمات شبکه‌های کامپیوتری و اینترنت",
	"فروشگاه لوازم آرایشی و بهداشتی",
}

// Catalog1405 returns a defensive copy of the reviewed initial catalog. Dates are
// Gregorian Tehran-local calendar dates and cover the imported 1405 history plus
// the first 90 forecast days after 2026-06-30.
func Catalog1405() []Event {
	events := []Event{
		officialEvent("fathers-day-1404", "روز پدر", "2026-01-03", "2026-01-03", "appreciation", true, []string{"هدیه", "قدردانی"}),
		officialEvent("mabath-1404", "مبعث پیامبر اکرم", "2026-01-17", "2026-01-17", "religious-holiday", true, []string{"تعطیل", "مناسبت-مذهبی"}),
		officialEvent("imam-mahdi-birthday-1404", "نیمه شعبان", "2026-02-04", "2026-02-04", "religious-holiday", true, []string{"تعطیل", "مناسبت-مذهبی"}),
		officialEvent("revolution-day-1404", "پیروزی انقلاب اسلامی", "2026-02-11", "2026-02-11", "national-holiday", true, []string{"تعطیل", "مناسبت-ملی"}),
		officialEvent("imam-ali-martyrdom-1404", "شهادت امام علی", "2026-03-11", "2026-03-11", "religious-holiday", true, []string{"تعطیل", "مناسبت-مذهبی"}),
		officialEvent("oil-nationalization-1404", "ملی شدن صنعت نفت", "2026-03-19", "2026-03-19", "national-holiday", true, []string{"تعطیل", "مناسبت-ملی"}),
		officialEvent("nowruz-1405", "نوروز", "2026-03-21", "2026-03-24", "new-year", true, []string{"هدیه", "خرید", "سال-نو", "تعطیل"}),
		officialEvent("islamic-republic-day-1405", "روز جمهوری اسلامی", "2026-04-01", "2026-04-01", "national-holiday", true, []string{"تعطیل", "مناسبت-ملی"}),
		officialEvent("nature-day-1405", "روز طبیعت", "2026-04-02", "2026-04-02", "leisure", true, []string{"تفریح", "خرید", "تعطیل"}),
		officialEvent("imam-sadegh-martyrdom-1405", "شهادت امام جعفر صادق", "2026-04-14", "2026-04-14", "religious-holiday", true, []string{"تعطیل", "مناسبت-مذهبی"}),
		officialEvent("teachers-day-1405", "روز معلم", "2026-05-02", "2026-05-02", "appreciation", false, []string{"هدیه", "آموزش", "قدردانی"}),
		officialEvent("eid-al-adha-1405", "عید قربان", "2026-05-27", "2026-05-27", "religious-holiday", true, []string{"تعطیل", "مناسبت-مذهبی"}),
		officialEvent("khomeini-ghadir-1405", "رحلت امام خمینی و عید غدیر", "2026-06-04", "2026-06-04", "official-holiday", true, []string{"تعطیل", "مناسبت-ملی", "مناسبت-مذهبی"}),
		officialEvent("khordad-15-1405", "قیام پانزده خرداد", "2026-06-05", "2026-06-05", "national-holiday", true, []string{"تعطیل", "مناسبت-ملی"}),
		officialEvent("tasua-1405", "تاسوعای حسینی", "2026-06-24", "2026-06-24", "religious-holiday", true, []string{"تعطیل", "مناسبت-مذهبی"}),
		officialEvent("ashura-1405", "عاشورای حسینی", "2026-06-25", "2026-06-25", "religious-holiday", true, []string{"تعطیل", "مناسبت-مذهبی"}),
		commercialEvent("summer-midseason-1405", "میانه فصل تابستان", "2026-07-15", "2026-07-17", "seasonal-shopping", []string{"خرید", "تابستان", "پیشنهاد-فصلی"}, importedMerchantCategories),
		officialEvent("arbaeen-1405", "اربعین حسینی", "2026-08-04", "2026-08-04", "religious-holiday", true, []string{"تعطیل", "مناسبت-مذهبی"}),
		officialEvent("prophet-demise-1405", "رحلت پیامبر اکرم و شهادت امام حسن", "2026-08-12", "2026-08-12", "religious-holiday", true, []string{"تعطیل", "مناسبت-مذهبی"}),
		officialEvent("doctors-day-1405", "روز پزشک", "2026-08-23", "2026-08-23", "appreciation", false, []string{"هدیه", "قدردانی", "حرفه‌ای"}),
		officialEvent("prophet-birthday-1405", "میلاد پیامبر اکرم و امام جعفر صادق", "2026-08-30", "2026-08-30", "religious-holiday", true, []string{"تعطیل", "مناسبت-مذهبی"}),
		commercialEvent("back-to-school-1405", "آمادگی بازگشایی مدارس", "2026-09-10", "2026-09-22", "education-season", []string{"آموزش", "خرید", "مدرسه"}, []string{"مراکز آموزشی مجازی", "کیف و کفش فروشی"}),
		commercialEvent("autumn-opening-1405", "آغاز فصل پاییز", "2026-09-23", "2026-09-28", "seasonal-shopping", []string{"خرید", "پاییز", "پیشنهاد-فصلی"}, importedMerchantCategories),
	}
	result := make([]Event, len(events))
	for index, event := range events {
		result[index] = event
		result[index].Tags = slices.Clone(event.Tags)
		result[index].Categories = slices.Clone(event.Categories)
	}
	return result
}

func officialEvent(id, title, start, end, family string, holiday bool, tags []string) Event {
	return Event{ID: id, TitleFA: title, StartDate: mustCatalogDate(start), EndDate: mustCatalogDate(end), Family: family, Tags: slices.Clone(tags), Source: officialCalendarSource, SourceVersion: officialCalendarVersion, Kind: EventOfficial, OfficialHoliday: holiday, Universal: true}
}

func commercialEvent(id, title, start, end, family string, tags, categories []string) Event {
	return Event{ID: id, TitleFA: title, StartDate: mustCatalogDate(start), EndDate: mustCatalogDate(end), Family: family, Tags: slices.Clone(tags), Source: curatedCommercialSource, SourceVersion: CatalogVersion, Categories: slices.Clone(categories), Kind: EventCommercial, Universal: false}
}

func ValidateCatalog(events []Event) error {
	seen := make(map[string]struct{}, len(events))
	for index, event := range events {
		if strings.TrimSpace(event.ID) == "" || strings.TrimSpace(event.TitleFA) == "" || strings.TrimSpace(event.Family) == "" || strings.TrimSpace(event.Source) == "" || strings.TrimSpace(event.SourceVersion) == "" {
			return fmt.Errorf("growth catalog event %d is incomplete", index)
		}
		if _, exists := seen[event.ID]; exists {
			return fmt.Errorf("growth catalog contains duplicate id %q", event.ID)
		}
		seen[event.ID] = struct{}{}
		if event.StartDate.IsZero() || event.EndDate.Before(event.StartDate) {
			return fmt.Errorf("growth catalog event %q has invalid date range", event.ID)
		}
		if event.Kind != EventOfficial && event.Kind != EventCommercial {
			return fmt.Errorf("growth catalog event %q has invalid kind", event.ID)
		}
		if len(normalizedSet(event.Tags)) == 0 {
			return fmt.Errorf("growth catalog event %q lacks tags", event.ID)
		}
		if event.Universal && len(event.Categories) != 0 {
			return fmt.Errorf("growth catalog universal event %q must not contain categories", event.ID)
		}
		if !event.Universal && len(event.Categories) == 0 {
			return fmt.Errorf("growth catalog scoped event %q lacks categories", event.ID)
		}
	}
	return nil
}

func mustCatalogDate(value string) time.Time {
	parsed, err := time.Parse(time.DateOnly, value)
	if err != nil {
		panic("invalid reviewed event catalog date: " + value)
	}
	return parsed
}