package cmd

import (
	"fmt"
	"slices"
	"time"

	"git.mlow.ca/mlow/lmcli/pkg/lmcli"
	"git.mlow.ca/mlow/lmcli/pkg/util"
	"github.com/spf13/cobra"
)

const (
	LS_COUNT int = 5
)

func ListCmd(ctx *lmcli.Context) *cobra.Command {
	cmd := &cobra.Command{
		Use:     "list",
		Aliases: []string{"ls"},
		Short:   "List conversations",
		Long:    `List conversations in order of recent activity`,
		RunE: func(cmd *cobra.Command, args []string) error {
			conversations, err := ctx.Store.Conversations()
			if err != nil {
				return fmt.Errorf("Could not fetch conversations: %v", err)
			}

			type Category struct {
				name   string
				cutoff time.Duration
			}

			type ConversationLine struct {
				timeSinceReply time.Duration
				formatted      string
			}

			now := time.Now()

			midnight := time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, now.Location())
			monthStart := time.Date(now.Year(), now.Month(), 1, 0, 0, 0, 0, now.Location())
			dayOfWeek := int(now.Weekday())
			categories := []Category{
				{"today", now.Sub(midnight)},
				{"yesterday", now.Sub(midnight.AddDate(0, 0, -1))},
				{"this week", now.Sub(midnight.AddDate(0, 0, -dayOfWeek))},
				{"last week", now.Sub(midnight.AddDate(0, 0, -(dayOfWeek + 7)))},
				{"this month", now.Sub(monthStart)},
				{"last month", now.Sub(monthStart.AddDate(0, -1, 0))},
				{"2 months ago", now.Sub(monthStart.AddDate(0, -2, 0))},
				{"3 months ago", now.Sub(monthStart.AddDate(0, -3, 0))},
				{"4 months ago", now.Sub(monthStart.AddDate(0, -4, 0))},
				{"5 months ago", now.Sub(monthStart.AddDate(0, -5, 0))},
				{"older", now.Sub(time.Time{})},
			}
			categorized := map[string][]ConversationLine{}

			all, _ := cmd.Flags().GetBool("all")

			for _, conversation := range conversations {
				lastMessage, err := ctx.Store.LastMessage(&conversation)
				if lastMessage == nil || err != nil {
					continue
				}

				messageAge := now.Sub(lastMessage.CreatedAt)

				var category string
				for _, c := range categories {
					if messageAge < c.cutoff {
						category = c.name
						break
					}
				}

				formatted := fmt.Sprintf(
					"%s - %s - %s",
					conversation.ShortName.String,
					util.HumanTimeElapsedSince(messageAge),
					conversation.Title,
				)

				categorized[category] = append(
					categorized[category],
					ConversationLine{messageAge, formatted},
				)
			}

			count, _ := cmd.Flags().GetInt("count")
			var conversationsPrinted int
		outer:
			for _, category := range categories {
				conversationLines, ok := categorized[category.name]
				if !ok {
					continue
				}

				slices.SortFunc(conversationLines, func(a, b ConversationLine) int {
					return int(a.timeSinceReply - b.timeSinceReply)
				})

				fmt.Printf("%s:\n", category.name)
				for _, conv := range conversationLines {
					if conversationsPrinted >= count && !all {
						fmt.Printf("%d remaining message(s), use --all to view.\n", len(conversations)-conversationsPrinted)
						break outer
					}

					fmt.Printf("  %s\n", conv.formatted)
					conversationsPrinted++
				}
			}
			return nil
		},
	}

	cmd.Flags().Bool("all", false, "Show all conversations")
	cmd.Flags().Int("count", LS_COUNT, "How many conversations to show")

	return cmd
}