package exporter

import (
    "encoding/json"
    "errors"
    "fmt"
    "marketing-system-data-tool/server/internal/schema"
    "strconv"
    "strings"
)

type BuildRequest struct {
    MainTable string
    Datasource string
    Fields    []string // table.field
    Filters   map[string]interface{}
}

func BuildSQL(req BuildRequest, whitelist map[string]bool) (string, []interface{}, error) {
    if req.MainTable != "order" && req.MainTable != "order_info" {
        return "", nil, errors.New("unsupported main table")
    }
    sch := schema.Get(req.Datasource, req.MainTable)
    cols := []string{}
    need := map[string]bool{}
    for _, tf := range req.Fields {
        if !whitelist[tf] {
            return "", nil, errors.New("field not allowed")
        }
        parts := strings.Split(tf, ".")
        if len(parts) != 2 {
            return "", nil, errors.New("invalid field format")
        }
        t, f := parts[0], parts[1]
        need[t] = true
        mt := sch.TableName(t)
        mf, _ := sch.MapField(t, f)
        if t == "order" && req.MainTable == "order" {
            if f == "status" {
                cols = append(cols, "CASE `order`.type WHEN 1 THEN '直充卡密' WHEN 2 THEN '立减金' WHEN 3 THEN '红包' ELSE '' END AS type")
                cols = append(cols, "CASE `order`.status WHEN 0 THEN '待充值' WHEN 1 THEN '充值中' WHEN 2 THEN '已完成' WHEN 3 THEN '充值失败' WHEN 4 THEN '已取消' WHEN 5 THEN '已过期' WHEN 6 THEN '待支付' END AS status")
                continue
            }
            if f == "type" {
                cols = append(cols, "CASE `order`.type WHEN 1 THEN '直充卡密' WHEN 2 THEN '立减金' WHEN 3 THEN '红包' ELSE '' END AS type")
                continue
            }
            if f == "pay_type" {
                cols = append(cols, "CASE `order`.pay_type WHEN 1 THEN '支付宝' WHEN 5 THEN '微信' ELSE '' END AS pay_type")
                continue
            }
            if f == "pay_status" {
                cols = append(cols, "CASE `order`.pay_status WHEN 1 THEN '待支付' WHEN 2 THEN '已支付' WHEN 3 THEN '已退款' ELSE '' END AS pay_status")
                continue
            }
        }
        if t == "order_cash" && f == "receive_status" {
            cols = append(cols, "CASE `order_cash`.receive_status WHEN 0 THEN '待领取' WHEN 1 THEN '领取中' WHEN 2 THEN '领取成功' WHEN 3 THEN '领取失败' ELSE '' END AS receive_status")
            continue
        }
        if t == "order_cash" && f == "channel" {
            cols = append(cols, "CASE `order_cash`.channel WHEN 1 THEN '支付宝' WHEN 2 THEN '微信' WHEN 3 THEN '云闪付' ELSE '' END AS channel")
            continue
        }
        if t == "order_voucher" && f == "channel" {
            cols = append(cols, "CASE `order_voucher`.channel WHEN 1 THEN '支付宝' WHEN 2 THEN '微信' ELSE '' END AS channel")
            continue
        }
        if t == "order_voucher" && f == "status" {
            cols = append(cols, "CASE `order_voucher`.status WHEN 1 THEN '可用' WHEN 2 THEN '已实扣' WHEN 3 THEN '已过期' WHEN 4 THEN '已退款' WHEN 5 THEN '领取失败' WHEN 6 THEN '发放中' WHEN 7 THEN '部分退款' WHEN 8 THEN '已退回' WHEN 9 THEN '发放失败' ELSE '' END AS status")
            continue
        }
        if t == "order_voucher" && f == "receive_mode" {
            cols = append(cols, "CASE `order_voucher`.receive_mode WHEN 1 THEN '渠道授权用户id' WHEN 2 THEN '手机号或邮箱' ELSE '' END AS receive_mode")
            continue
        }
        if t == "order_voucher" && f == "out_biz_no" {
            cols = append(cols, "'' AS out_biz_no")
            continue
        }
        cols = append(cols, "`"+mt+"`."+escape(mf))
    }
	if len(cols) == 0 {
		return "", nil, errors.New("no fields")
	}
	sb := strings.Builder{}
	sb.WriteString("SELECT ")
	sb.WriteString(strings.Join(cols, ","))
    sb.WriteString(" FROM `" + req.MainTable + "`")
    for _, j := range sch.BuildJoins(need, req.MainTable) {
        sb.WriteString(j)
    }

	args := []interface{}{}
	where := []string{}
	// collect need from filters referencing related tables
	if _, ok := req.Filters["order_cash_cash_activity_id_eq"]; ok {
		need["order_cash"] = true
	}
	if _, ok := req.Filters["order_voucher_channel_activity_id_eq"]; ok {
		need["order_voucher"] = true
	}
	if _, ok := req.Filters["voucher_batch_channel_activity_id_eq"]; ok {
		need["voucher_batch"] = true
		need["voucher"] = true
		need["order_voucher"] = true
	}
	if _, ok := req.Filters["merchant_out_biz_no_eq"]; ok {
		need["merchant_key_send"] = true
	}
    if v, ok := req.Filters["creator_in"]; ok {
        ids := []interface{}{}
		switch t := v.(type) {
		case []interface{}:
			ids = t
		case []int:
			for _, x := range t {
				ids = append(ids, x)
			}
		case []string:
			for _, x := range t {
				ids = append(ids, x)
			}
		}
		if len(ids) == 0 {
			return "", nil, errors.New("creator_in required")
		}
        ph := strings.Repeat("?,", len(ids))
        ph = strings.TrimSuffix(ph, ",")
        if tbl, col, ok := sch.FilterColumn("creator_in"); ok {
            where = append(where, fmt.Sprintf("`%s`.%s IN (%s)", sch.TableName(tbl), escape(col), ph))
        }
        args = append(args, ids...)
    }
    if v, ok := req.Filters["create_time_between"]; ok {
		var arr []interface{}
		b, _ := json.Marshal(v)
		json.Unmarshal(b, &arr)
		if len(arr) != 2 {
			return "", nil, errors.New("create_time_between requires 2 values")
		}
        if tbl, col, ok := sch.FilterColumn("create_time_between"); ok {
            where = append(where, fmt.Sprintf("`%s`.%s BETWEEN ? AND ?", sch.TableName(tbl), escape(col)))
        }
        args = append(args, arr[0], arr[1])
    }
    if v, ok := req.Filters["type_eq"]; ok {
		var tv int
		switch t := v.(type) {
		case float64:
			tv = int(t)
		case int:
			tv = t
		case string:
			// simple digits parsing
			for i := 0; i < len(t); i++ {
				c := t[i]
				if c < '0' || c > '9' {
					continue
				}
				tv = tv*10 + int(c-'0')
			}
		}
        if tv == 1 || tv == 2 || tv == 3 {
            if tbl, col, ok := sch.FilterColumn("type_eq"); ok {
                where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
            }
            args = append(args, tv)
        }
    }
    if v, ok := req.Filters["out_trade_no_eq"]; ok {
        s := toString(v)
        if s != "" {
            if tbl, col, ok := sch.FilterColumn("out_trade_no_eq"); ok {
                where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
            }
            args = append(args, s)
        }
    }
    if v, ok := req.Filters["account_eq"]; ok {
        s := toString(v)
        if s != "" {
            if tbl, col, ok := sch.FilterColumn("account_eq"); ok {
                where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
            }
            args = append(args, s)
        }
    }
    if v, ok := req.Filters["plan_id_eq"]; ok {
        s := toString(v)
        if s != "" {
            if tbl, col, ok := sch.FilterColumn("plan_id_eq"); ok {
                where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
            }
            args = append(args, s)
        }
    }
    if v, ok := req.Filters["key_batch_id_eq"]; ok {
        s := toString(v)
        if s != "" {
            if tbl, col, ok := sch.FilterColumn("key_batch_id_eq"); ok {
                where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
            }
            args = append(args, s)
        }
    }
    if v, ok := req.Filters["product_id_eq"]; ok {
        s := toString(v)
        if s != "" {
            if tbl, col, ok := sch.FilterColumn("product_id_eq"); ok {
                where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
            }
            args = append(args, s)
        }
    }
    if v, ok := req.Filters["reseller_id_eq"]; ok {
        s := toString(v)
        if s != "" {
            if tbl, col, ok := sch.FilterColumn("reseller_id_eq"); ok {
                where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
            }
            args = append(args, s)
        }
    }
    if v, ok := req.Filters["code_batch_id_eq"]; ok {
        s := toString(v)
        if s != "" {
            if tbl, col, ok := sch.FilterColumn("code_batch_id_eq"); ok {
                where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
            }
            args = append(args, s)
        }
    }
    if v, ok := req.Filters["order_cash_cash_activity_id_eq"]; ok {
        s := toString(v)
        if s != "" {
            if tbl, col, ok := sch.FilterColumn("order_cash_cash_activity_id_eq"); ok {
                where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
            }
            args = append(args, s)
        }
    }
    if v, ok := req.Filters["order_voucher_channel_activity_id_eq"]; ok {
        s := toString(v)
        if s != "" {
            if tbl, col, ok := sch.FilterColumn("order_voucher_channel_activity_id_eq"); ok {
                where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
            }
            args = append(args, s)
        }
    }
    if v, ok := req.Filters["voucher_batch_channel_activity_id_eq"]; ok {
        s := toString(v)
        if s != "" {
            if tbl, col, ok := sch.FilterColumn("voucher_batch_channel_activity_id_eq"); ok {
                where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
                args = append(args, s)
            }
        }
    }
    if v, ok := req.Filters["merchant_out_biz_no_eq"]; ok {
        s := toString(v)
        if s != "" {
            if tbl, col, ok := sch.FilterColumn("merchant_out_biz_no_eq"); ok {
                where = append(where, fmt.Sprintf("`%s`.%s = ?", sch.TableName(tbl), escape(col)))
            }
            args = append(args, s)
        }
    }
	if len(where) > 0 {
		sb.WriteString(" WHERE ")
		sb.WriteString(strings.Join(where, " AND "))
	}
	return sb.String(), args, nil
}

func escape(s string) string {
	if s == "key" {
		return "`key`"
	}
	if s == "index" {
		return "`index`"
	}
	return s
}

func toString(v interface{}) string {
	switch t := v.(type) {
	case []byte:
		return string(t)
	case string:
		return t
	case int64:
		return strconv.FormatInt(t, 10)
	case int:
		return strconv.Itoa(t)
	case float64:
		return strconv.FormatFloat(t, 'f', -1, 64)
	default:
		return ""
	}
}