package fadada

import (
	"fmt"
	"strings"
	"time"
)

// FillTemplate 填写文档模板并生成合同文件（POST /doc-template/fill-values）
func (c *Client) FillTemplate(req *ContractFillRequest) (*ContractFileResult, error) {
	if err := c.config.ValidateTemplateFields(); err != nil {
		return nil, err
	}
	if err := validateContractFillRequest(req); err != nil {
		return nil, err
	}

	accessToken, err := c.ensureAccessToken()
	if err != nil {
		return nil, err
	}

	signDate := strings.TrimSpace(req.SignDate)
	if signDate == "" {
		signDate = time.Now().Format("2006年01月02日")
	}

	fileName := strings.TrimSpace(req.FileName)
	if fileName == "" {
		if c.config.Contract != nil && c.config.Contract.Name != "" {
			fileName = c.config.Contract.Name
		} else {
			fileName = "海宇数据-合作协议"
		}
		fileName = fmt.Sprintf("%s-%s", fileName, strings.TrimSpace(req.AgreementNo))
	}

	fieldValues := c.BuildTemplateFieldValues(&ContractFillRequest{
		AgreementNo:       req.AgreementNo,
		CompanyName:       req.CompanyName,
		UnifiedSocialCode: req.UnifiedSocialCode,
		EnterpriseAddress: req.EnterpriseAddress,
		AuthorizedRepName: req.AuthorizedRepName,
		SignDate:          signDate,
	})

	docFieldValues := make([]docFieldValue, 0, len(fieldValues))
	for _, fv := range fieldValues {
		docFieldValues = append(docFieldValues, docFieldValue{
			FieldID:    fv.FieldID,
			FieldValue: fv.FieldValue,
		})
	}

	res, err := c.http.PostBiz(pathFillDocTemplateValues, accessToken, &fillDocTemplateReq{
		OwnerID:        &openID{IDType: "corp", OpenID: c.config.OpenCorpID},
		DocTemplateID:  c.config.TemplateID,
		FileName:       fileName,
		DocFieldValues: docFieldValues,
	})
	if err != nil {
		return nil, err
	}
	if res.Code != successCode {
		return nil, fmt.Errorf("法大大填写模板失败: code=%s msg=%s requestId=%s", res.Code, res.Msg, res.RequestID)
	}

	var data fillDocTemplateData
	if err := decodeData(res.Data, &data); err != nil {
		return nil, fmt.Errorf("解析模板填单响应失败: %w", err)
	}
	if data.FileID == "" {
		return nil, fmt.Errorf("法大大填写模板失败: fileId 为空 requestId=%s", res.RequestID)
	}

	return &ContractFileResult{
		FileID:          data.FileID,
		FileDownloadURL: data.FileDownloadURL,
	}, nil
}

// FillSignTaskFields 向已创建的签署任务填写控件（POST /sign-task/field/fill-values）
func (c *Client) FillSignTaskFields(signTaskID string, req *ContractFillRequest) error {
	if strings.TrimSpace(signTaskID) == "" {
		return fmt.Errorf("signTaskId 不能为空")
	}
	if err := c.config.ValidateTemplateFields(); err != nil {
		return err
	}
	if err := validateContractFillRequest(req); err != nil {
		return err
	}

	accessToken, err := c.ensureAccessToken()
	if err != nil {
		return err
	}

	docID, err := c.resolveSignTaskDocID(signTaskID, accessToken)
	if err != nil {
		return err
	}

	signDate := strings.TrimSpace(req.SignDate)
	if signDate == "" {
		signDate = time.Now().Format("2006年01月02日")
	}

	fieldValues := c.BuildTemplateFieldValues(&ContractFillRequest{
		AgreementNo:       req.AgreementNo,
		CompanyName:       req.CompanyName,
		UnifiedSocialCode: req.UnifiedSocialCode,
		EnterpriseAddress: req.EnterpriseAddress,
		AuthorizedRepName: req.AuthorizedRepName,
		SignDate:          signDate,
	})

	docFieldValues := make([]docFieldValue, 0, len(fieldValues))
	for _, fv := range fieldValues {
		docFieldValues = append(docFieldValues, docFieldValue{
			DocID:      docID,
			FieldDocID: docID,
			FieldID:    fv.FieldID,
			FieldValue: fv.FieldValue,
		})
	}

	res, err := c.http.PostBiz(pathFillSignTaskFieldValues, accessToken, &fillSignTaskFieldsReq{
		SignTaskID:     signTaskID,
		DocFieldValues: docFieldValues,
	})
	if err != nil {
		return err
	}
	if res.Code != successCode {
		return fmt.Errorf("法大大签署任务填单失败: code=%s msg=%s requestId=%s", res.Code, res.Msg, res.RequestID)
	}
	return nil
}

// resolveSignTaskDocID 解析签署任务文档 docId（填单必填）
func (c *Client) resolveSignTaskDocID(signTaskID, accessToken string) (string, error) {
	if c.config != nil {
		if id := strings.TrimSpace(c.config.TemplateDocID); id != "" {
			return id, nil
		}
	}

	res, err := c.http.PostBiz(pathGetSignTaskDetail, accessToken, &getSignTaskDetailReq{
		SignTaskID: signTaskID,
	})
	if err != nil {
		return "", fmt.Errorf("查询签署任务文档失败: %w", err)
	}
	if res.Code != successCode {
		return "", fmt.Errorf("查询签署任务文档失败: code=%s msg=%s requestId=%s", res.Code, res.Msg, res.RequestID)
	}

	var data getSignTaskDetailData
	if err := decodeData(res.Data, &data); err != nil {
		return "", fmt.Errorf("解析签署任务文档失败: %w", err)
	}
	for _, d := range data.Docs {
		if id := strings.TrimSpace(d.DocID); id != "" {
			return id, nil
		}
	}
	return "", fmt.Errorf("签署任务未返回 docId，请在配置 fadada.template_doc_id 中填写模板文档ID")
}

// BuildTemplateFieldValues 将业务字段映射为法大大控件编码/值
func (c *Client) BuildTemplateFieldValues(req *ContractFillRequest) []TemplateFieldValue {
	fields := c.config.TemplateFields
	if fields == nil || req == nil {
		return nil
	}
	signDate := strings.TrimSpace(req.SignDate)
	agreementNo := strings.TrimSpace(req.AgreementNo)
	companyName := strings.TrimSpace(req.CompanyName)

	pairs := make([]struct {
		fieldID string
		value   string
	}, 0, len(fields.AgreementNo)+len(fields.PartyAName)+6)
	for _, id := range fields.AgreementNo {
		id = strings.TrimSpace(id)
		if id == "" {
			continue
		}
		pairs = append(pairs, struct {
			fieldID string
			value   string
		}{id, agreementNo})
	}
	for _, id := range fields.PartyAName {
		id = strings.TrimSpace(id)
		if id == "" {
			continue
		}
		pairs = append(pairs, struct {
			fieldID string
			value   string
		}{id, companyName})
	}
	pairs = append(pairs,
		struct {
			fieldID string
			value   string
		}{fields.ContractDate, signDate},
		struct {
			fieldID string
			value   string
		}{fields.PartyAUSCC, strings.TrimSpace(req.UnifiedSocialCode)},
		struct {
			fieldID string
			value   string
		}{fields.PartyAAddress, strings.TrimSpace(req.EnterpriseAddress)},
		struct {
			fieldID string
			value   string
		}{fields.PartyARep, strings.TrimSpace(req.AuthorizedRepName)},
		struct {
			fieldID string
			value   string
		}{fields.PartyASignDate, signDate},
		struct {
			fieldID string
			value   string
		}{fields.PartyBSignDate, signDate},
	)

	out := make([]TemplateFieldValue, 0, len(pairs))
	for _, p := range pairs {
		if p.fieldID == "" {
			continue
		}
		out = append(out, TemplateFieldValue{
			FieldID:    p.fieldID,
			FieldValue: p.value,
		})
	}
	return out
}

func validateContractFillRequest(req *ContractFillRequest) error {
	if req == nil {
		return fmt.Errorf("合同填单请求不能为空")
	}
	if strings.TrimSpace(req.AgreementNo) == "" {
		return fmt.Errorf("协议编号不能为空")
	}
	if strings.TrimSpace(req.CompanyName) == "" {
		return fmt.Errorf("甲方企业名不能为空")
	}
	if strings.TrimSpace(req.UnifiedSocialCode) == "" {
		return fmt.Errorf("甲方统一信用代码不能为空")
	}
	if strings.TrimSpace(req.AuthorizedRepName) == "" {
		return fmt.Errorf("甲方授权代表不能为空")
	}
	return nil
}