package bizdev

import (
	"context"
	"errors"
	"fmt"
	"path/filepath"
	"strings"

	"chat-agent-system/internal/squad"
	"chat-agent-system/internal/storage"
)

// ResolveMaterials 将请求材料 + 项目 CAS 资产解析为可注入工作区的 squad 材料。
// 项目内全部有效资产自动纳入（含私密文档）；显式附件优先并去重。
func (s *Service) ResolveMaterials(ctx context.Context, req TaskRunRequest) ([]squad.MaterialItem, map[string]any, error) {
	manifest := map[string]any{
		"explicit_materials": len(req.Materials),
	}
	byKey := make(map[string]squad.MaterialItem)

	addItem := func(item squad.MaterialItem) error {
		if strings.TrimSpace(item.Filename) == "" {
			return errors.New("material filename required")
		}
		if len(item.Content) == 0 {
			return fmt.Errorf("material %q has no extractable content", item.Filename)
		}
		key := item.Filename
		if item.AssetID > 0 {
			key = fmt.Sprintf("asset:%d", item.AssetID)
		}
		byKey[key] = item
		return nil
	}

	// 1. 项目资产池（不要求用户本轮再次附加）
	if s.cas != nil && req.ProjectID > 0 {
		refs, err := s.cas.ListProjectRefs(ctx, req.ProjectID)
		if err != nil {
			return nil, nil, err
		}
		var assetEntries []map[string]any
		for _, ref := range refs {
			data, loadedRef, err := s.cas.ReadRefBytes(ctx, ref.ID)
			if err != nil {
				continue
			}
			text, err := squad.ExtractTextWithAnchors(loadedRef.FileName, data)
			if err != nil {
				return nil, nil, fmt.Errorf("extract project asset %q: %w", loadedRef.FileName, err)
			}
			if strings.TrimSpace(text) == "" {
				return nil, nil, fmt.Errorf("project asset %q extracted empty text", loadedRef.FileName)
			}
			item := squad.MaterialItem{
				Filename: loadedRef.FileName,
				Content:  []byte(text),
				AssetID:  loadedRef.ID,
				SHA256:   loadedRef.BlobSHA256,
				OwnerID:  loadedRef.UserID,
			}
			_ = addItem(item)
			assetEntries = append(assetEntries, map[string]any{
				"asset_id":       loadedRef.ID,
				"filename":       loadedRef.FileName,
				"sha256":         loadedRef.BlobSHA256,
				"owner_user_id":  loadedRef.UserID,
				"file_category":  loadedRef.FileCategory,
				"source":         "project_asset_pool",
			})
		}
		manifest["project_assets"] = assetEntries
	}

	// 2. 显式附件（asset_id 优先，其次 inline content）
	for _, m := range req.Materials {
		if m.AssetID > 0 && s.cas != nil {
			data, ref, err := s.cas.ReadRefBytes(ctx, m.AssetID)
			if err != nil {
				return nil, nil, fmt.Errorf("load attachment asset_id=%d: %w", m.AssetID, err)
			}
			if ref.ProjectID > 0 && req.ProjectID > 0 && ref.ProjectID != req.ProjectID {
				return nil, nil, fmt.Errorf("asset_id=%d belongs to another project", m.AssetID)
			}
			filename := m.Filename
			if filename == "" {
				filename = ref.FileName
			}
			text, err := squad.ExtractTextWithAnchors(filename, data)
			if err != nil {
				return nil, nil, fmt.Errorf("extract attachment %q: %w", filename, err)
			}
			if strings.TrimSpace(text) == "" {
				return nil, nil, fmt.Errorf("attachment %q extracted empty text", filename)
			}
			if err := addItem(squad.MaterialItem{
				Filename: filename,
				Content:  []byte(text),
				AssetID:  ref.ID,
				SHA256:   ref.BlobSHA256,
				OwnerID:  ref.UserID,
			}); err != nil {
				return nil, nil, err
			}
			continue
		}

		filename := strings.TrimSpace(m.Filename)
		if filename == "" {
			return nil, nil, errors.New("material filename required when asset_id absent")
		}
		if len(m.Content) == 0 {
			return nil, nil, fmt.Errorf("material %q has empty content and no asset_id", filename)
		}
		text, err := squad.ExtractTextWithAnchors(filename, m.Content)
		if err != nil {
			return nil, nil, fmt.Errorf("extract inline material %q: %w", filename, err)
		}
		if strings.TrimSpace(text) == "" {
			return nil, nil, fmt.Errorf("inline material %q extracted empty text", filename)
		}
		if err := addItem(squad.MaterialItem{
			Filename: filepath.Base(filename),
			Content:  []byte(text),
		}); err != nil {
			return nil, nil, err
		}
	}

	out := make([]squad.MaterialItem, 0, len(byKey))
	for _, item := range byKey {
		out = append(out, item)
	}
	manifest["resolved_count"] = len(out)
	return out, manifest, nil
}

// ValidateTaskRunIdentity 拒绝缺失项目/会话标识的任务启动。
func ValidateTaskRunIdentity(sessionID string, projectID int64) error {
	if strings.TrimSpace(sessionID) == "" {
		return errors.New("session_id required for task run")
	}
	if projectID <= 0 {
		return errors.New("project_id required for task run")
	}
	return nil
}

// MaterialInputFromRef 由 CAS 引用构造任务材料输入（供上传 API 测试）。
func MaterialInputFromRef(ref *storage.FileReference) MaterialInput {
	if ref == nil {
		return MaterialInput{}
	}
	return MaterialInput{
		Filename: ref.FileName,
		AssetID:  ref.ID,
	}
}