package postgres

import (
	"fmt"
	"slices"
	"strings"
	"time"

	"github.com/pkg/errors"
	exprv1 "google.golang.org/genproto/googleapis/api/expr/v1alpha1"

	"github.com/usememos/memos/plugin/filter"
)

func (d *DB) ConvertExprToSQL(ctx *filter.ConvertContext, expr *exprv1.Expr) error {
	if v, ok := expr.ExprKind.(*exprv1.Expr_CallExpr); ok {
		switch v.CallExpr.Function {
		case "_||_", "_&&_":
			if len(v.CallExpr.Args) != 2 {
				return errors.Errorf("invalid number of arguments for %s", v.CallExpr.Function)
			}
			if _, err := ctx.Buffer.WriteString("("); err != nil {
				return err
			}
			if err := d.ConvertExprToSQL(ctx, v.CallExpr.Args[0]); err != nil {
				return err
			}
			operator := "AND"
			if v.CallExpr.Function == "_||_" {
				operator = "OR"
			}
			if _, err := ctx.Buffer.WriteString(fmt.Sprintf(" %s ", operator)); err != nil {
				return err
			}
			if err := d.ConvertExprToSQL(ctx, v.CallExpr.Args[1]); err != nil {
				return err
			}
			if _, err := ctx.Buffer.WriteString(")"); err != nil {
				return err
			}
		case "!_":
			if len(v.CallExpr.Args) != 1 {
				return errors.Errorf("invalid number of arguments for %s", v.CallExpr.Function)
			}
			if _, err := ctx.Buffer.WriteString("NOT ("); err != nil {
				return err
			}
			if err := d.ConvertExprToSQL(ctx, v.CallExpr.Args[0]); err != nil {
				return err
			}
			if _, err := ctx.Buffer.WriteString(")"); err != nil {
				return err
			}
		case "_==_", "_!=_", "_<_", "_>_", "_<=_", "_>=_":
			if len(v.CallExpr.Args) != 2 {
				return errors.Errorf("invalid number of arguments for %s", v.CallExpr.Function)
			}
			identifier, err := filter.GetIdentExprName(v.CallExpr.Args[0])
			if err != nil {
				return err
			}
			if !slices.Contains([]string{"create_time", "update_time", "visibility", "content"}, identifier) {
				return errors.Errorf("invalid identifier for %s", v.CallExpr.Function)
			}
			value, err := filter.GetConstValue(v.CallExpr.Args[1])
			if err != nil {
				return err
			}
			operator := "="
			switch v.CallExpr.Function {
			case "_==_":
				operator = "="
			case "_!=_":
				operator = "!="
			case "_<_":
				operator = "<"
			case "_>_":
				operator = ">"
			case "_<=_":
				operator = "<="
			case "_>=_":
				operator = ">="
			}

			if identifier == "create_time" || identifier == "update_time" {
				timestampStr, ok := value.(string)
				if !ok {
					return errors.New("invalid timestamp value")
				}
				timestamp, err := time.Parse(time.RFC3339, timestampStr)
				if err != nil {
					return errors.Wrap(err, "failed to parse timestamp")
				}

				var factor string
				if identifier == "create_time" {
					factor = "memo.created_ts"
				} else if identifier == "update_time" {
					factor = "memo.updated_ts"
				}
				if _, err := ctx.Buffer.WriteString(fmt.Sprintf("%s %s %s", factor, operator, placeholder(len(ctx.Args)+ctx.ArgsOffset+1))); err != nil {
					return err
				}
				ctx.Args = append(ctx.Args, timestamp.Unix())
			} else if identifier == "visibility" || identifier == "content" {
				if operator != "=" && operator != "!=" {
					return errors.Errorf("invalid operator for %s", v.CallExpr.Function)
				}
				valueStr, ok := value.(string)
				if !ok {
					return errors.New("invalid string value")
				}

				var factor string
				if identifier == "visibility" {
					factor = "memo.visibility"
				} else if identifier == "content" {
					factor = "memo.content"
				}
				if _, err := ctx.Buffer.WriteString(fmt.Sprintf("%s %s %s", factor, operator, placeholder(len(ctx.Args)+ctx.ArgsOffset+1))); err != nil {
					return err
				}
				ctx.Args = append(ctx.Args, valueStr)
			}
		case "@in":
			if len(v.CallExpr.Args) != 2 {
				return errors.Errorf("invalid number of arguments for %s", v.CallExpr.Function)
			}
			identifier, err := filter.GetIdentExprName(v.CallExpr.Args[0])
			if err != nil {
				return err
			}
			if !slices.Contains([]string{"tag", "visibility"}, identifier) {
				return errors.Errorf("invalid identifier for %s", v.CallExpr.Function)
			}

			values := []any{}
			for _, element := range v.CallExpr.Args[1].GetListExpr().Elements {
				value, err := filter.GetConstValue(element)
				if err != nil {
					return err
				}
				values = append(values, value)
			}
			if identifier == "tag" {
				subcodition := []string{}
				args := []any{}
				for _, v := range values {
					subcodition, args = append(subcodition, fmt.Sprintf(`memo.payload->'tags' @> %s::jsonb`, placeholder(len(ctx.Args)+ctx.ArgsOffset+len(args)+1))), append(args, []any{v})
				}
				if len(subcodition) == 1 {
					if _, err := ctx.Buffer.WriteString(subcodition[0]); err != nil {
						return err
					}
				} else {
					if _, err := ctx.Buffer.WriteString(fmt.Sprintf("(%s)", strings.Join(subcodition, " OR "))); err != nil {
						return err
					}
				}
				ctx.Args = append(ctx.Args, args...)
			} else if identifier == "visibility" {
				placeholders := []string{}
				for i := range values {
					placeholders = append(placeholders, placeholder(len(ctx.Args)+ctx.ArgsOffset+i+1))
				}
				if _, err := ctx.Buffer.WriteString(fmt.Sprintf("memo.visibility IN (%s)", strings.Join(placeholders, ","))); err != nil {
					return err
				}
				ctx.Args = append(ctx.Args, values...)
			}
		case "contains":
			if len(v.CallExpr.Args) != 1 {
				return errors.Errorf("invalid number of arguments for %s", v.CallExpr.Function)
			}
			identifier, err := filter.GetIdentExprName(v.CallExpr.Target)
			if err != nil {
				return err
			}
			if identifier != "content" {
				return errors.Errorf("invalid identifier for %s", v.CallExpr.Function)
			}
			arg, err := filter.GetConstValue(v.CallExpr.Args[0])
			if err != nil {
				return err
			}
			if _, err := ctx.Buffer.WriteString("memo.content ILIKE LIKE " + placeholder(len(ctx.Args)+ctx.ArgsOffset+1)); err != nil {
				return err
			}
			ctx.Args = append(ctx.Args, fmt.Sprintf("%%%s%%", arg))
		}
	}
	return nil
}
