package models

import (
	"time"

	"task-dashboard/internal/config"
)

type TimelineItemType string

const (
	TimelineItemTypeTask  TimelineItemType = "task"
	TimelineItemTypeMeal  TimelineItemType = "meal"
	TimelineItemTypeCard  TimelineItemType = "card"
	TimelineItemTypeEvent TimelineItemType = "event"
	TimelineItemTypeGTask TimelineItemType = "gtask" // Google Tasks
)

type DaySection string

const (
	DaySectionToday    DaySection = "today"
	DaySectionTomorrow DaySection = "tomorrow"
	DaySectionLater    DaySection = "later"
)

type TimelineItem struct {
	ID           string           `json:"id"`
	Type         TimelineItemType `json:"type"`
	Title        string           `json:"title"`
	Time         time.Time        `json:"time"`
	EndTime      *time.Time       `json:"end_time,omitempty"`
	Description  string           `json:"description,omitempty"`
	URL          string           `json:"url,omitempty"`
	OriginalItem interface{}      `json:"-"`

	// UI enhancement fields
	IsCompleted bool       `json:"is_completed"`
	IsOverdue   bool       `json:"is_overdue"`
	IsAllDay    bool       `json:"is_all_day"` // True if time is midnight (no specific time)
	DaySection  DaySection `json:"day_section"`
	Source      string     `json:"source"` // "trello", "plantoeat", "calendar", "gtasks"

	// Undated is true only for genuinely dateless Task/GTask items (the
	// caller uses Time=now as a layout placeholder for them -- see
	// timeline_logic.go's nativeUndated/gtask-no-due-date branches).
	// Deliberately NOT the same thing as IsAllDay: doot-native and Google
	// Tasks due dates are ALWAYS midnight-anchored even when a task has a
	// real due date (see reference_google_tasks_due_date_utc_quirk), so
	// IsAllDay ends up true for both "no due date" and "has a due date, but
	// it's date-only" -- a distinction the WEB UI doesn't need (it buckets
	// by DaySection, computed from Time regardless of IsAllDay, and only
	// uses IsAllDay for a same-day visual choice that's fine either way for
	// tasks) but the ANDROID WIDGET does: TimelineItemToWidgetItem uses
	// Undated, not IsAllDay, to decide whether to populate wi.Start, because
	// the widget's undated/floating pool has no per-day awareness at all --
	// conflating "no date" with "dated but time-only-midnight" there means
	// a task due tomorrow renders as if due today (2026-08-10 report).
	Undated bool `json:"-"`

	// Source-specific metadata
	ListID           string `json:"list_id,omitempty"`            // For Google Tasks
	RecurringEventID string `json:"recurring_event_id,omitempty"` // For calendar events
	ProjectColor     string `json:"project_color,omitempty"`      // For doot-native tasks with a project assigned
	ChainPosition    int    `json:"chain_position,omitempty"`     // For doot-native tasks that belong to a linear chain (1-indexed for display)
	ChainTotal       int    `json:"chain_total,omitempty"`        // Total tasks in the chain, paired with ChainPosition
	BucketState      string `json:"bucket_state,omitempty"`       // "active" for doot-native tasks that are a maintenance-bucket item (dormant items never reach the timeline)
}

// ComputeDaySection sets the DaySection, IsOverdue, and IsAllDay based on the item's time
func (item *TimelineItem) ComputeDaySection(now time.Time) {
	// Use configured display timezone for consistent comparisons
	tz := config.GetDisplayTimezone()
	localNow := now.In(tz)
	localItemTime := item.Time.In(tz)

	today := time.Date(localNow.Year(), localNow.Month(), localNow.Day(), 0, 0, 0, 0, tz)
	tomorrow := today.AddDate(0, 0, 1)
	dayAfterTomorrow := today.AddDate(0, 0, 2)

	itemDay := time.Date(localItemTime.Year(), localItemTime.Month(), localItemTime.Day(), 0, 0, 0, 0, tz)

	// Check if item is overdue (before today)
	item.IsOverdue = itemDay.Before(today)

	// Check if item is all-day (midnight time means no specific time).
	// Only ever sets IsAllDay to true here -- never clears a true a caller
	// already set (e.g. nativeUndated/gtask "no due date" tasks, which use
	// IsAllDay as a floating-task marker with Time set to "now", not
	// midnight -- clobbering it back to false made them look like real
	// scheduled items to the widget client).
	if localItemTime.Hour() == 0 && localItemTime.Minute() == 0 {
		item.IsAllDay = true
	}

	if itemDay.Before(tomorrow) {
		item.DaySection = DaySectionToday
	} else if itemDay.Before(dayAfterTomorrow) {
		item.DaySection = DaySectionTomorrow
	} else {
		item.DaySection = DaySectionLater
	}
}