package persona

import (
	"context"
	"strings"

	app "haixun-backend/internal/library/errors"
	"haixun-backend/internal/library/errors/code"
	libviral "haixun-backend/internal/library/viral"
	domai "haixun-backend/internal/model/ai/domain/usecase"
	aiusecase "haixun-backend/internal/model/ai/usecase"
	copydraftusecase "haixun-backend/internal/model/copy_draft/domain/usecase"
	"haixun-backend/internal/svc"
	"haixun-backend/internal/types"
)

type GeneratePersonaCopyDraftLogic struct {
	ctx    context.Context
	svcCtx *svc.ServiceContext
}

func NewGeneratePersonaCopyDraftLogic(ctx context.Context, svcCtx *svc.ServiceContext) *GeneratePersonaCopyDraftLogic {
	return &GeneratePersonaCopyDraftLogic{ctx: ctx, svcCtx: svcCtx}
}

func (l *GeneratePersonaCopyDraftLogic) GeneratePersonaCopyDraft(
	req *types.GeneratePersonaCopyDraftHandlerReq,
) (*types.GeneratePersonaCopyDraftData, error) {
	tenantID, uid, err := actorFrom(l.ctx)
	if err != nil {
		return nil, err
	}
	personaID := strings.TrimSpace(req.ID)
	scanPostID := strings.TrimSpace(req.ScanPostID)
	if scanPostID == "" {
		return nil, app.For(code.Persona).InputMissingRequired("scan_post_id is required")
	}

	persona, err := l.svcCtx.Persona.Get(l.ctx, tenantID, uid, personaID)
	if err != nil {
		return nil, err
	}
	post, err := l.svcCtx.ScanPost.GetForPersona(l.ctx, tenantID, uid, personaID, scanPostID)
	if err != nil {
		return nil, err
	}

	credential, err := l.svcCtx.ThreadsAccount.ResolveMemberAiCredential(l.ctx, tenantID, uid)
	if err != nil {
		return nil, err
	}
	providerID, err := aiusecase.MapWorkerProvider(credential.Provider)
	if err != nil {
		return nil, err
	}

	result, err := l.svcCtx.AI.GenerateText(l.ctx, domai.GenerateRequest{
		Provider: providerID,
		Model:    credential.Model,
		Credential: domai.Credential{
			APIKey: credential.APIKey,
		},
		System: libviral.BuildSystemPrompt(),
		Messages: []domai.Message{
			{
				Role: "user",
				Content: libviral.BuildUserPrompt(libviral.ReplicateInput{
					TopicLabel:   post.SearchTag,
					TopicBrief:   persona.Brief,
					Persona:      persona.Persona,
					StyleProfile: persona.StyleProfile,
					OriginalText: post.Text,
					AuthorName:   post.Author,
				}),
			},
		},
	})
	if err != nil {
		return nil, err
	}

	parsed, err := libviral.ParseReplicateOutput(result.Text)
	if err != nil {
		return nil, app.For(code.AI).SvcThirdParty("仿寫 LLM 回傳無法解析：" + err.Error())
	}

	saved, err := l.svcCtx.CopyDraft.Create(l.ctx, copydraftusecase.CreateRequest{
		TenantID:       tenantID,
		OwnerUID:       uid,
		PersonaID:      personaID,
		ScanPostID:     scanPostID,
		DraftType:      "replicate",
		Text:           parsed.Text,
		Angle:          parsed.Angle,
		Hook:           parsed.Hook,
		Rationale:      parsed.Rationale,
		ReferenceNotes: parsed.StructureNotes,
		Sources:        []string{post.Permalink},
	})
	if err != nil {
		return nil, err
	}

	return &types.GeneratePersonaCopyDraftData{
		Draft: types.CopyDraftData{
			ID:             saved.ID,
			PersonaID:      saved.PersonaID,
			ScanPostID:     saved.ScanPostID,
			DraftType:      saved.DraftType,
			Text:           saved.Text,
			Angle:          saved.Angle,
			Hook:           saved.Hook,
			Rationale:      saved.Rationale,
			ReferenceNotes: saved.ReferenceNotes,
			Sources:        saved.Sources,
			Status:         saved.Status,
			CreateAt:       saved.CreateAt,
		},
		Message: "已產出仿寫草稿",
	}, nil
}