package duty_schedule

import (
	"errors"
	"sort"
	"strings"
	"time"
)

var (
	ErrInvalid  = errors.New("值班排班信息不符合要求")
	ErrNotFound = errors.New("值班组或排班不存在")
	ErrConflict = errors.New("数据已被其他人员更新，请刷新后重试")
	ErrCoverage = errors.New("周排班存在空档或重叠")
)

type GroupInput struct {
	Name            string `json:"name"`
	Timezone        string `json:"timezone"`
	ExpectedVersion int    `json:"expectedVersion"`
}
type MemberInput struct {
	ContactID string `json:"contactId"`
	Role      string `json:"role"`
}
type SlotInput struct {
	Weekday          int    `json:"weekday"`
	StartMinute      int    `json:"startMinute"`
	EndMinute        int    `json:"endMinute"`
	PrimaryContactID string `json:"primaryContactId"`
	BackupContactID  string `json:"backupContactId"`
}
type ScheduleInput struct {
	EffectiveFrom time.Time   `json:"effectiveFrom"`
	EffectiveTo   *time.Time  `json:"effectiveTo"`
	Slots         []SlotInput `json:"slots"`
}
type OverrideInput struct {
	OriginalContactID    string    `json:"originalContactId"`
	ReplacementContactID string    `json:"replacementContactId"`
	StartsAt             time.Time `json:"startsAt"`
	EndsAt               time.Time `json:"endsAt"`
	Reason               string    `json:"reason"`
}

func normalizeGroup(input GroupInput) (GroupInput, error) {
	input.Name = strings.TrimSpace(input.Name)
	input.Timezone = strings.TrimSpace(input.Timezone)
	if input.Name == "" || len([]rune(input.Name)) > 128 {
		return GroupInput{}, ErrInvalid
	}
	if _, err := time.LoadLocation(input.Timezone); err != nil {
		return GroupInput{}, ErrInvalid
	}
	return input, nil
}
func validateSlots(slots []SlotInput) error {
	if len(slots) == 0 {
		return ErrCoverage
	}
	byDay := map[int][]SlotInput{}
	for _, slot := range slots {
		if slot.Weekday < 0 || slot.Weekday > 6 || slot.StartMinute < 0 || slot.EndMinute > 1440 || slot.StartMinute >= slot.EndMinute || slot.PrimaryContactID == "" || slot.BackupContactID == "" || slot.PrimaryContactID == slot.BackupContactID {
			return ErrInvalid
		}
		byDay[slot.Weekday] = append(byDay[slot.Weekday], slot)
	}
	for day := 0; day < 7; day++ {
		daySlots := byDay[day]
		sort.Slice(daySlots, func(i, j int) bool { return daySlots[i].StartMinute < daySlots[j].StartMinute })
		cursor := 0
		for _, slot := range daySlots {
			if slot.StartMinute != cursor {
				return ErrCoverage
			}
			cursor = slot.EndMinute
		}
		if cursor != 1440 {
			return ErrCoverage
		}
	}
	return nil
}
func normalizeOverride(input OverrideInput) (OverrideInput, error) {
	input.Reason = strings.TrimSpace(input.Reason)
	if input.OriginalContactID == "" || input.ReplacementContactID == "" || input.OriginalContactID == input.ReplacementContactID || input.StartsAt.IsZero() || !input.EndsAt.After(input.StartsAt) || input.Reason == "" || len([]rune(input.Reason)) > 256 {
		return OverrideInput{}, ErrInvalid
	}
	return input, nil
}