package fin

import (
	"bytes"
	"encoding/json"
	"errors"
	"io"
	"time"

	"git.apinb.com/bsm-sdk/core/errcode"
	"git.apinb.com/bsm-sdk/core/infra"
	"git.apinb.com/heqiapp/platforms/backend/api/internal/logic/common"
	"git.apinb.com/heqiapp/platforms/backend/api/internal/models"
	"github.com/gin-gonic/gin"
)

func FinSettlementHandlers() (gin.HandlerFunc, gin.HandlerFunc, gin.HandlerFunc, gin.HandlerFunc) {
	fields := []string{"settlement_no", "subject_type", "subject_id", "period_start", "period_end"}
	return func(ctx *gin.Context) { common.ListResource(ctx, &models.FinSettlement{}) },
		func(ctx *gin.Context) {
			if err := rewriteSettlementSubject(ctx); err != nil {
				infra.Response.Error(ctx, errcode.ErrInvalidArgument)
				return
			}
			_, create, _, _ := common.ResourceHandlers(&models.FinSettlement{}, fields, fields)
			create(ctx)
		},
		func(ctx *gin.Context) { common.GetResource(ctx, &models.FinSettlement{}) },
		func(ctx *gin.Context) {
			if err := rewriteSettlementSubject(ctx); err != nil {
				infra.Response.Error(ctx, errcode.ErrInvalidArgument)
				return
			}
			_, _, _, update := common.ResourceHandlers(&models.FinSettlement{}, fields, fields)
			update(ctx)
		}
}

func rewriteSettlementSubject(ctx *gin.Context) error {
	var input map[string]any
	if err := ctx.ShouldBindJSON(&input); err != nil {
		return err
	}
	if !validSettlementPeriod(input["period_start"], input["period_end"]) {
		return errors.New("invalid settlement period")
	}
	subjectType, _ := input["subject_type"].(string)
	identity, _ := input["subject_identity"].(string)
	var model any
	switch subjectType {
	case "gas", "gas_basic":
		model = &models.GasBasic{}
	case "delivery", "delivery_basic":
		model = &models.DeliveryBasic{}
	case "staff", "staff_account":
		model = &models.StaffAccount{}
	default:
		return errors.New("invalid settlement subject")
	}
	id, err := common.ResolveIdentityID(model, identity, true)
	if err != nil {
		return err
	}
	delete(input, "subject_identity")
	input["subject_id"] = id
	encoded, err := json.Marshal(input)
	if err != nil {
		return err
	}
	ctx.Request.Body = io.NopCloser(bytes.NewReader(encoded))
	return nil
}

func validSettlementPeriod(startValue, endValue any) bool {
	startText, startOK := startValue.(string)
	endText, endOK := endValue.(string)
	if !startOK || !endOK {
		return false
	}
	start, startErr := time.Parse(time.RFC3339, startText)
	end, endErr := time.Parse(time.RFC3339, endText)
	return startErr == nil && endErr == nil && end.After(start)
}