package exporter

import (
	"encoding/json"
	"errors"
	"strconv"
	"strings"
)

type BuildRequest struct {
	MainTable 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")
    }
	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
        if t == "order" {
            if f == "status" {
                cols = append(cols, "CASE `order`.type " +
                    "WHEN 1 THEN (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) " +
                    "WHEN 2 THEN (CASE `order`.status WHEN 0 THEN '待领取' WHEN 1 THEN '待领取' WHEN 2 THEN '已领取' WHEN 3 THEN '领取失败' WHEN 4 THEN '已取消' WHEN 5 THEN '已过期' WHEN 6 THEN '待支付' END) " +
                    "WHEN 3 THEN (CASE `order`.status WHEN 0 THEN '待领取' WHEN 1 THEN '待领取' WHEN 2 THEN '已核销' WHEN 3 THEN '领取失败' WHEN 4 THEN '已取消' WHEN 5 THEN '已过期' WHEN 6 THEN '' END) " +
                    "ELSE (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) END AS status")
            } else 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")
			} else 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")
			} else 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")
			} else 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")
			} else {
				cols = append(cols, "`order`."+escape(f))
			}
        } else {
            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")
            } else 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")
            } else 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")
            } else 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")
            } else 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")
            } else if t == "order_voucher" && f == "out_biz_no" {
                cols = append(cols, "'' AS out_biz_no")
            } else {
                cols = append(cols, "`"+t+"`."+escape(f))
            }
        }
	}
	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 + "`")
	// JOINs based on need
	// order_detail
    if need["order_detail"] && req.MainTable == "order" {
        sb.WriteString(" LEFT JOIN `order_detail` ON `order_detail`.order_number = `order`.order_number")
    }
    // order_cash
    if need["order_cash"] {
        if req.MainTable == "order_info" {
            sb.WriteString(" LEFT JOIN `order_cash` ON `order_cash`.order_no = `order_info`.order_no")
        } else {
            sb.WriteString(" LEFT JOIN `order_cash` ON `order_cash`.order_number = `order`.order_number")
        }
    }
    // order_voucher
    if need["order_voucher"] {
        if req.MainTable == "order_info" {
            sb.WriteString(" LEFT JOIN `order_voucher` ON `order_voucher`.order_no = `order_info`.order_no")
        } else {
            sb.WriteString(" LEFT JOIN `order_voucher` ON `order_voucher`.order_number = `order`.order_number")
        }
    }
	// plan
    if req.MainTable == "order" {
        if need["plan"] || need["key_batch"] {
            sb.WriteString(" LEFT JOIN `plan` ON `plan`.id = `order`.plan_id")
        }
        if need["key_batch"] {
            sb.WriteString(" LEFT JOIN `key_batch` ON `key_batch`.plan_id = `plan`.id")
        }
        if need["code_batch"] {
            sb.WriteString(" LEFT JOIN `code_batch` ON `code_batch`.key_batch_id = `key_batch`.id")
        }
        if need["voucher"] {
            sb.WriteString(" LEFT JOIN `voucher` ON `voucher`.channel_activity_id = `order_voucher`.channel_activity_id")
        }
        if need["voucher_batch"] {
            sb.WriteString(" LEFT JOIN `voucher_batch` ON `voucher_batch`.voucher_id = `voucher`.id")
        }
        if need["merchant_key_send"] {
            sb.WriteString(" LEFT JOIN `merchant_key_send` ON `order`." + escape("key") + " = `merchant_key_send`.key")
        }
    }

	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 req.MainTable == "order_info" {
            where = append(where, "`order_info`.user_id IN ("+ph+")")
        } else {
            where = append(where, "`order`.creator IN ("+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 req.MainTable == "order_info" {
            where = append(where, "`order_info`.create_time BETWEEN ? AND ?")
        } else {
            where = append(where, "`order`.create_time BETWEEN ? AND ?")
        }
        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 req.MainTable == "order_info" {
                where = append(where, "`order_info`.type = ?")
            } else {
                where = append(where, "`order`.type = ?")
            }
            args = append(args, tv)
        }
    }
    if v, ok := req.Filters["out_trade_no_eq"]; ok {
        s := toString(v)
        if s != "" {
            if req.MainTable == "order_info" {
                where = append(where, "`order_info`.out_order_no = ?")
            } else {
                where = append(where, "`order`.out_trade_no = ?")
            }
            args = append(args, s)
        }
    }
    if v, ok := req.Filters["account_eq"]; ok {
        s := toString(v)
        if s != "" {
            if req.MainTable == "order_info" {
                where = append(where, "`order_info`.account = ?")
            } else {
                where = append(where, "`order`.account = ?")
            }
            args = append(args, s)
        }
    }
    if v, ok := req.Filters["plan_id_eq"]; ok {
        s := toString(v)
        if s != "" {
            if req.MainTable == "order_info" {
                where = append(where, "`order_info`.activity_id = ?")
            } else {
                where = append(where, "`order`.plan_id = ?")
            }
            args = append(args, s)
        }
    }
    if v, ok := req.Filters["key_batch_id_eq"]; ok {
        s := toString(v)
        if s != "" {
            if req.MainTable == "order_info" {
                where = append(where, "`order_info`.key_batch_name = ?")
            } else {
                where = append(where, "`order`.key_batch_id = ?")
            }
            args = append(args, s)
        }
    }
    if v, ok := req.Filters["product_id_eq"]; ok {
        s := toString(v)
        if s != "" {
            if req.MainTable == "order_info" {
                where = append(where, "`order_info`.goods_id = ?")
            } else {
                where = append(where, "`order`.product_id = ?")
            }
            args = append(args, s)
        }
    }
    if v, ok := req.Filters["reseller_id_eq"]; ok {
        s := toString(v)
        if s != "" {
            if req.MainTable == "order_info" {
                where = append(where, "`order_info`.merchant_id = ?")
            } else {
                where = append(where, "`order`.reseller_id = ?")
            }
            args = append(args, s)
        }
    }
    if v, ok := req.Filters["code_batch_id_eq"]; ok {
        s := toString(v)
        if s != "" {
            if req.MainTable == "order_info" {
                where = append(where, "`order_info`.supplier_product_id = ?")
            } else {
                where = append(where, "`order`.code_batch_id = ?")
            }
            args = append(args, s)
        }
    }
    if v, ok := req.Filters["order_cash_cash_activity_id_eq"]; ok {
        s := toString(v)
        if s != "" {
            if req.MainTable == "order_info" {
                where = append(where, "`order_cash`.activity_id = ?")
            } else {
                where = append(where, "`order_cash`.cash_activity_id = ?")
            }
            args = append(args, s)
        }
    }
    if v, ok := req.Filters["order_voucher_channel_activity_id_eq"]; ok {
        s := toString(v)
        if s != "" {
            if req.MainTable == "order_info" {
                where = append(where, "`order_voucher`.channel_batch_no = ?")
            } else {
                where = append(where, "`order_voucher`.channel_activity_id = ?")
            }
            args = append(args, s)
        }
    }
    if v, ok := req.Filters["voucher_batch_channel_activity_id_eq"]; ok {
        s := toString(v)
        if s != "" {
            if req.MainTable == "order" { // only marketing schema has voucher_batch
                where = append(where, "`voucher_batch`.channel_activity_id = ?")
                args = append(args, s)
            }
        }
    }
    if v, ok := req.Filters["merchant_out_biz_no_eq"]; ok {
        s := toString(v)
        if s != "" {
            if req.MainTable == "order" { // marketing only
                where = append(where, "`merchant_key_send`.out_biz_no = ?")
            }
            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`"
	}
	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 ""
	}
}