package serv

import (
	"bytes"
	"fmt"
	"io"

	"github.com/dosco/super-graph/jsn"
)

func varMap(ctx *coreContext) func(w io.Writer, tag string) (int, error) {
	return func(w io.Writer, tag string) (int, error) {
		switch tag {
		case "user_id":
			if v := ctx.Value(userIDKey); v != nil {
				return stringVar(w, v.(string))
			}
			return 0, errNoUserID

		case "user_id_provider":
			if v := ctx.Value(userIDProviderKey); v != nil {
				return stringVar(w, v.(string))
			}
			return 0, errNoUserID
		}

		fields := jsn.Get(ctx.req.Vars, [][]byte{[]byte(tag)})
		if len(fields) == 0 {
			return 0, fmt.Errorf("variable '%s' not found", tag)
		}

		is := false

		for i := range fields[0].Value {
			c := fields[0].Value[i]
			if c != ' ' {
				is = (c == '"') || (c == '{') || (c == '[')
				break
			}
		}

		if is {
			return stringVarB(w, fields[0].Value)
		}

		w.Write(fields[0].Value)
		return 0, nil
	}
}

func varList(ctx *coreContext, args [][]byte) []interface{} {
	vars := make([]interface{}, len(args))

	var fields map[string]interface{}
	var err error

	if len(ctx.req.Vars) != 0 {
		fields, _, err = jsn.Tree(ctx.req.Vars)

		if err != nil {
			logger.Warn().Err(err).Msg("Failed to parse variables")
		}
	}

	for i := range args {
		av := args[i]

		switch {
		case bytes.Equal(av, []byte("user_id")):
			if v := ctx.Value(userIDKey); v != nil {
				vars[i] = v.(string)
			}

		case bytes.Equal(av, []byte("user_id_provider")):
			if v := ctx.Value(userIDProviderKey); v != nil {
				vars[i] = v.(string)
			}

		default:
			if v, ok := fields[string(av)]; ok {
				vars[i] = v
			}
		}
	}

	return vars
}

func stringVar(w io.Writer, v string) (int, error) {
	if n, err := w.Write([]byte(`'`)); err != nil {
		return n, err
	}
	if n, err := w.Write([]byte(v)); err != nil {
		return n, err
	}
	return w.Write([]byte(`'`))
}

func stringVarB(w io.Writer, v []byte) (int, error) {
	if n, err := w.Write([]byte(`'`)); err != nil {
		return n, err
	}
	if n, err := w.Write(v); err != nil {
		return n, err
	}
	return w.Write([]byte(`'`))
}