package service

import (
	"context"
	"encoding/json"
	"fmt"
	"sync"
	"time"

	"github.com/gochat/gochat/internal/model"
	"github.com/gochat/gochat/internal/worker"
)

const (
	TaskTypeCaptainDocumentSync            = "captain:document_sync"
	TaskTypeCaptainDocumentCrawl           = "captain:document_crawl"
	TaskTypeCaptainDocumentPageCrawlParse  = "captain:document_page_crawl_parse"
	TaskTypeCaptainDocumentScheduleSyncs   = "captain:documents_schedule_syncs"
	TaskTypeCaptainDocumentResponseBuilder = "captain:document_response_builder"
	TaskTypeCaptainLLMUpdateEmbedding      = "captain:llm_update_embedding"
)

const captainDocumentScheduleInterval = 24 * time.Hour

type captainDocumentSyncJob struct {
	AccountID  uint `json:"account_id"`
	DocumentID uint `json:"document_id"`
}

type captainDocumentCrawlJob struct {
	AccountID  uint `json:"account_id"`
	DocumentID uint `json:"document_id"`
}

type captainDocumentPageCrawlParseJob struct {
	AccountID   uint   `json:"account_id"`
	AssistantID uint   `json:"assistant_id"`
	PageLink    string `json:"page_link"`
}

type captainDocumentScheduleSyncsJob struct {
	PlanName string `json:"plan_name,omitempty"`
}

type captainDocumentResponseBuilderJob struct {
	AccountID  uint `json:"account_id"`
	DocumentID uint `json:"document_id"`
}

type captainLLMUpdateEmbeddingJob struct {
	AccountID  uint   `json:"account_id"`
	ResponseID uint   `json:"response_id"`
	Content    string `json:"content,omitempty"`
}

var captainDocumentRegistrations sync.Map

// RegisterCaptainDocumentJobs wires Captain::Documents::PerformSyncJob into
// the durable worker. The sync backend remains fakeable for tests and disabled
// deployments.
func RegisterCaptainDocumentJobs(wp *worker.WorkerPool, svc *CaptainDocumentService) {
	if wp == nil || svc == nil {
		return
	}
	if _, loaded := captainDocumentRegistrations.LoadOrStore(wp, struct{}{}); loaded {
		return
	}
	wp.Register(TaskTypeCaptainDocumentSync, svc.performDocumentSyncJob)
	wp.Register(TaskTypeCaptainDocumentCrawl, svc.performDocumentCrawlJob)
	wp.Register(TaskTypeCaptainDocumentPageCrawlParse, svc.performDocumentPageCrawlParseJob)
	wp.Register(TaskTypeCaptainDocumentScheduleSyncs, svc.performDocumentScheduleSyncsJob)
	wp.Register(TaskTypeCaptainDocumentResponseBuilder, svc.performDocumentResponseBuilderJob)
	wp.Register(TaskTypeCaptainLLMUpdateEmbedding, svc.performCaptainLLMUpdateEmbeddingJob)
}

func EnqueueCaptainDocumentScheduleSyncs(ctx context.Context, wp *worker.WorkerPool, scheduledAt time.Time) (*model.BackgroundJob, error) {
	if wp == nil {
		return nil, nil
	}
	if scheduledAt.IsZero() {
		scheduledAt = time.Now()
	}
	return wp.Enqueue(ctx, TaskTypeCaptainDocumentScheduleSyncs, captainDocumentScheduleSyncsJob{},
		worker.WithQueue("scheduled_jobs"),
		worker.WithScheduledAt(scheduledAt),
		worker.WithMaxAttempts(3),
		worker.WithIdempotencyKey(captainDocumentScheduleIdempotencyKey(scheduledAt)),
	)
}

func captainDocumentScheduleIdempotencyKey(scheduledAt time.Time) string {
	bucket := scheduledAt.UTC().Truncate(captainDocumentScheduleInterval).Unix()
	return fmt.Sprintf("captain:documents_schedule_syncs:%d", bucket)
}

func (s *CaptainDocumentService) performDocumentSyncJob(ctx context.Context, job *model.BackgroundJob) error {
	var payload captainDocumentSyncJob
	if err := json.Unmarshal(job.Payload, &payload); err != nil {
		return fmt.Errorf("unmarshal captain document sync job: %w", err)
	}
	if payload.AccountID == 0 || payload.DocumentID == 0 {
		return fmt.Errorf("invalid captain document sync job payload: %#v", payload)
	}
	_, err := s.SyncDocumentByAccount(ctx, payload.AccountID, payload.DocumentID)
	return err
}

func (s *CaptainDocumentService) performDocumentCrawlJob(ctx context.Context, job *model.BackgroundJob) error {
	var payload captainDocumentCrawlJob
	if err := json.Unmarshal(job.Payload, &payload); err != nil {
		return fmt.Errorf("unmarshal captain document crawl job: %w", err)
	}
	if payload.AccountID == 0 || payload.DocumentID == 0 {
		return fmt.Errorf("invalid captain document crawl job payload: %#v", payload)
	}
	_, err := s.CrawlDocumentByAccount(ctx, payload.AccountID, payload.DocumentID)
	return err
}

func (s *CaptainDocumentService) performDocumentPageCrawlParseJob(ctx context.Context, job *model.BackgroundJob) error {
	var payload captainDocumentPageCrawlParseJob
	if err := json.Unmarshal(job.Payload, &payload); err != nil {
		return fmt.Errorf("unmarshal captain document page crawl parse job: %w", err)
	}
	if payload.AccountID == 0 || payload.AssistantID == 0 || payload.PageLink == "" {
		return fmt.Errorf("invalid captain document page crawl parse job payload: %#v", payload)
	}
	_, err := s.ParseCrawledPage(ctx, payload.AccountID, payload.AssistantID, payload.PageLink)
	return err
}

func (s *CaptainDocumentService) performDocumentScheduleSyncsJob(ctx context.Context, job *model.BackgroundJob) error {
	if len(job.Payload) > 0 {
		var payload captainDocumentScheduleSyncsJob
		if err := json.Unmarshal(job.Payload, &payload); err != nil {
			return fmt.Errorf("unmarshal captain document schedule syncs job: %w", err)
		}
	}
	if _, err := s.ScheduleDueDocumentSyncs(ctx, time.Now()); err != nil {
		return err
	}
	_, err := EnqueueCaptainDocumentScheduleSyncs(ctx, s.worker, time.Now().Add(captainDocumentScheduleInterval))
	return err
}

func (s *CaptainDocumentService) performDocumentResponseBuilderJob(ctx context.Context, job *model.BackgroundJob) error {
	var payload captainDocumentResponseBuilderJob
	if err := json.Unmarshal(job.Payload, &payload); err != nil {
		return fmt.Errorf("unmarshal captain document response builder job: %w", err)
	}
	if payload.AccountID == 0 || payload.DocumentID == 0 {
		return fmt.Errorf("invalid captain document response builder job payload: %#v", payload)
	}
	_, err := s.BuildResponsesForDocumentByAccount(ctx, payload.AccountID, payload.DocumentID)
	return err
}

func (s *CaptainDocumentService) performCaptainLLMUpdateEmbeddingJob(ctx context.Context, job *model.BackgroundJob) error {
	var payload captainLLMUpdateEmbeddingJob
	if err := json.Unmarshal(job.Payload, &payload); err != nil {
		return fmt.Errorf("unmarshal captain llm update embedding job: %w", err)
	}
	if payload.AccountID == 0 || payload.ResponseID == 0 {
		return fmt.Errorf("invalid captain llm update embedding job payload: %#v", payload)
	}
	_, err := s.UpdateAssistantResponseEmbeddingByAccount(ctx, payload.AccountID, payload.ResponseID, payload.Content)
	return err
}