package tradesignal

import (
	"encoding/json"
	"errors"
	"fmt"
	"strings"

	"aiaa-notification-service/internal/config"
)

var ErrInvalidSignal = errors.New("invalid signal")

type Converter struct {
	overrides map[string]config.StrategyOverride
	positions *Tracker
}

func NewConverter(overrides map[string]config.StrategyOverride) *Converter {
	return &Converter{
		overrides: overrides,
		positions: NewTracker(),
	}
}

func (c *Converter) Convert(body []byte) (string, map[string]interface{}, error) {
	var sig Signal
	if err := json.Unmarshal(body, &sig); err != nil {
		return "", nil, fmt.Errorf("%w: %v", ErrInvalidSignal, err)
	}
	if strings.TrimSpace(sig.Action) == "" {
		return "", nil, fmt.Errorf("%w: missing action", ErrInvalidSignal)
	}
	out := Apply(&sig, c.overrideFor(sig.StrategyCode))
	snap := c.positions.Apply(out)
	var opts FormatOptions
	if snap.HasAvg {
		avg := snap.AvgPrice
		opts.AvgPrice = &avg
	}
	text := Format(out, opts)
	data, err := toData(body, out)
	if err != nil {
		return "", nil, err
	}
	data["formatted"] = text
	if snap.HasAvg {
		data["avgPrice"] = snap.AvgPrice
	}
	return "trade." + strings.ToLower(out.Action), data, nil
}

func (c *Converter) overrideFor(code string) *config.StrategyOverride {
	if c == nil || len(c.overrides) == 0 || code == "" {
		return nil
	}
	override, ok := c.overrides[code]
	if !ok {
		return nil
	}
	return &override
}

func toData(body []byte, sig *Signal) (map[string]interface{}, error) {
	data := make(map[string]interface{})
	if err := json.Unmarshal(body, &data); err != nil {
		return nil, err
	}
	raw, err := json.Marshal(sig)
	if err != nil {
		return nil, err
	}
	overlay := make(map[string]interface{})
	if err := json.Unmarshal(raw, &overlay); err != nil {
		return nil, err
	}
	for k, v := range overlay {
		data[k] = v
	}
	return data, nil
}