package directlinks

import (
	"context"
	"errors"
	"fmt"
	"sync/atomic"
	"time"

	"github.com/charmbracelet/log"
	"github.com/duke-git/lancet/v2/slice"
	"github.com/gotd/td/telegram/message/entity"
	"github.com/gotd/td/telegram/message/styling"
	"github.com/gotd/td/tg"
	"github.com/krau/SaveAny-Bot/common/utils/dlutil"
	"github.com/krau/SaveAny-Bot/common/utils/tgutil"
)

type TaskInfo interface {
	TotalBytes() int64
	TotalFiles() int
	TaskID() string
	StorageName() string
	StoragePath() string
	DownloadedBytes() int64
	Processing() []FileInfo
}

type FileInfo interface {
	FileName() string
	FileSize() int64
}

type ProgressTracker interface {
	OnStart(ctx context.Context, info TaskInfo)
	OnProgress(ctx context.Context, info TaskInfo)
	OnDone(ctx context.Context, info TaskInfo, err error)
}

type Progress struct {
	msgID             int
	chatID            int64
	start             time.Time
	lastUpdatePercent atomic.Int32
}

// OnDone implements ProgressTracker.
func (p *Progress) OnDone(ctx context.Context, info TaskInfo, err error) {
	logger := log.FromContext(ctx)
	if err != nil {
		if errors.Is(err, context.Canceled) {
			logger.Infof("Parsed task %s was canceled", info.TaskID())
			ext := tgutil.ExtFromContext(ctx)
			if ext != nil {
				ext.EditMessage(p.chatID, &tg.MessagesEditMessageRequest{
					ID:      p.msgID,
					Message: fmt.Sprintf("处理已取消: %s", info.TaskID()),
				})
			}
		} else {
			logger.Errorf("Parsed task %s failed: %s", info.TaskID(), err)
			ext := tgutil.ExtFromContext(ctx)
			if ext != nil {
				ext.EditMessage(p.chatID, &tg.MessagesEditMessageRequest{
					ID:      p.msgID,
					Message: fmt.Sprintf("处理失败: %s", err.Error()),
				})
			}
		}
		return
	}
	logger.Infof("Parsed task %s completed successfully", info.TaskID())

	entityBuilder := entity.Builder{}
	if err := styling.Perform(&entityBuilder,
		styling.Plain("处理完成, 文件数量: "),
		styling.Code(fmt.Sprintf("%d", info.TotalFiles())),
		styling.Plain("\n保存路径: "),
		styling.Code(fmt.Sprintf("[%s]:%s", info.StorageName(), info.StoragePath())),
	); err != nil {
		logger.Errorf("Failed to build entities: %s", err)
		return
	}
	text, entities := entityBuilder.Complete()
	req := &tg.MessagesEditMessageRequest{
		ID: p.msgID,
	}
	req.SetMessage(text)
	req.SetEntities(entities)

	ext := tgutil.ExtFromContext(ctx)
	if ext != nil {
		ext.EditMessage(p.chatID, req)
	}
}

// OnProgress implements ProgressTracker.
func (p *Progress) OnProgress(ctx context.Context, info TaskInfo) {
	if !shouldUpdateProgress(info.TotalBytes(), info.DownloadedBytes(), int(p.lastUpdatePercent.Load())) {
		return
	}
	percent := int((info.DownloadedBytes() * 100) / info.TotalBytes())
	if p.lastUpdatePercent.Load() == int32(percent) {
		return
	}
	p.lastUpdatePercent.Store(int32(percent))
	log.FromContext(ctx).Debugf("Progress update: %s, %d/%d", info.TaskID(), info.DownloadedBytes(), info.TotalBytes())
	entityBuilder := entity.Builder{}
	var entities []tg.MessageEntityClass
	if err := styling.Perform(&entityBuilder,
		styling.Plain("正在下载\n总大小: "),
		styling.Code(fmt.Sprintf("%.2f MB (%d个文件)", float64(info.TotalBytes())/(1024*1024), info.TotalFiles())),
		styling.Plain("\n正在处理:\n"),
		func() styling.StyledTextOption {
			var lines []string
			for _, elem := range info.Processing() {
				lines = append(lines, fmt.Sprintf("  - %s (%.2f MB)", elem.FileName(), float64(elem.FileSize())/(1024*1024)))
			}
			if len(lines) == 0 {
				lines = append(lines, "  - 无")
			}
			return styling.Plain(slice.Join(lines, "\n"))
		}(),
		styling.Plain("\n平均速度: "),
		styling.Bold(fmt.Sprintf("%.2f MB/s", dlutil.GetSpeed(info.DownloadedBytes(), p.start)/(1024*1024))),
		styling.Plain("\n当前进度: "),
		styling.Bold(fmt.Sprintf("%.2f%%", float64(info.DownloadedBytes())/float64(info.TotalBytes())*100)),
	); err != nil {
		log.FromContext(ctx).Errorf("Failed to build entities: %s", err)
		return
	}
	text, entities := entityBuilder.Complete()
	req := &tg.MessagesEditMessageRequest{
		ID: p.msgID,
	}
	req.SetMessage(text)
	req.SetEntities(entities)
	req.SetReplyMarkup(&tg.ReplyInlineMarkup{
		Rows: []tg.KeyboardButtonRow{
			{
				Buttons: []tg.KeyboardButtonClass{
					tgutil.BuildCancelButton(info.TaskID()),
				},
			},
		}},
	)
	ext := tgutil.ExtFromContext(ctx)
	if ext != nil {
		ext.EditMessage(p.chatID, req)
		return
	}
}

// OnStart implements ProgressTracker.
func (p *Progress) OnStart(ctx context.Context, info TaskInfo) {
	logger := log.FromContext(ctx)
	p.start = time.Now()
	p.lastUpdatePercent.Store(0)
	logger.Infof("Direct links task started: message_id=%d, chat_id=%d", p.msgID, p.chatID)
	ext := tgutil.ExtFromContext(ctx)
	if ext == nil {
		return
	}
	entityBuilder := entity.Builder{}
	var entities []tg.MessageEntityClass
	if err := styling.Perform(&entityBuilder,
		styling.Plain(fmt.Sprintf("开始下载, 总大小: %.2f MB (%d 个文件)", float64(info.TotalBytes())/(1024*1024), info.TotalFiles()))); err != nil {
		log.FromContext(ctx).Errorf("Failed to build entities: %s", err)
		return
	}
	text, entities := entityBuilder.Complete()
	req := &tg.MessagesEditMessageRequest{
		ID: p.msgID,
	}
	req.SetMessage(text)
	req.SetEntities(entities)
	req.SetReplyMarkup(&tg.ReplyInlineMarkup{
		Rows: []tg.KeyboardButtonRow{
			{
				Buttons: []tg.KeyboardButtonClass{
					tgutil.BuildCancelButton(info.TaskID()),
				},
			},
		}},
	)
	ext.EditMessage(p.chatID, req)
}

var _ ProgressTracker = (*Progress)(nil)

func NewProgress(msgID int, userID int64) ProgressTracker {
	return &Progress{
		msgID:  msgID,
		chatID: userID,
	}
}