package common

import (
	"crypto/rand"
	"encoding/hex"
	"encoding/json"
	"fmt"
)

// Commands are separate from the run revision. The live game session applies
// them only during Preparation, so a web command cannot invalidate settlement.
type CurrencyWarsCommand struct {
	ID       string `json:"id"`
	UID      uint32 `json:"uid"`
	RunID    uint32 `json:"run_id"`
	Field    string `json:"field"`
	Value    uint32 `json:"value"`
	Quantity uint32 `json:"quantity,omitempty"`
	Star     uint32 `json:"star,omitempty"`
}

func ReadCurrencyWarsCommands() ([]CurrencyWarsCommand, error) {
	root, err := readCurrencyWarsPersistentRoot()
	if err != nil {
		return nil, err
	}
	var commands []CurrencyWarsCommand
	if raw, ok := root["currency_wars_commands"]; ok {
		err = json.Unmarshal(raw, &commands)
	}
	return commands, err
}

func QueueCurrencyWarsCommand(uid, runID uint32, field string, value uint32) (string, error) {
	return QueueCurrencyWarsGrant(uid, runID, field, value, 1, 0)
}

func QueueCurrencyWarsGrant(uid, runID uint32, field string, value, quantity, star uint32) (string, error) {
	if uid == 0 || runID == 0 || quantity == 0 || (field != "gold" && field != "hp" && field != "exp" && field != "equip" && field != "role" && field != "orb" && field != "consumable" && field != "forge") {
		return "", fmt.Errorf("invalid CW command")
	}
	var nonce [16]byte
	if _, err := rand.Read(nonce[:]); err != nil {
		return "", err
	}
	id := hex.EncodeToString(nonce[:])
	persistentWriteMu.Lock()
	defer persistentWriteMu.Unlock()
	unlock, err := lockPersistentFile()
	if err != nil {
		return "", err
	}
	defer unlock()
	root, err := readCurrencyWarsPersistentRoot()
	if err != nil {
		return "", err
	}
	var commands []CurrencyWarsCommand
	if raw, ok := root["currency_wars_commands"]; ok {
		if err = json.Unmarshal(raw, &commands); err != nil {
			return "", err
		}
	}
	commands = append(commands, CurrencyWarsCommand{ID: id, UID: uid, RunID: runID, Field: field, Value: value, Quantity: quantity, Star: star})
	raw, err := json.Marshal(commands)
	if err != nil {
		return "", err
	}
	root["currency_wars_commands"] = raw
	return id, writeJSONAtomic("persistent", root)
}

func AcknowledgeCurrencyWarsCommand(id string) error {
	persistentWriteMu.Lock()
	defer persistentWriteMu.Unlock()
	unlock, err := lockPersistentFile()
	if err != nil {
		return err
	}
	defer unlock()
	root, err := readCurrencyWarsPersistentRoot()
	if err != nil {
		return err
	}
	var commands []CurrencyWarsCommand
	if raw, ok := root["currency_wars_commands"]; ok {
		if err = json.Unmarshal(raw, &commands); err != nil {
			return err
		}
	}
	remaining := commands[:0]
	for _, c := range commands {
		if c.ID != id {
			remaining = append(remaining, c)
		}
	}
	raw, err := json.Marshal(remaining)
	if err != nil {
		return err
	}
	root["currency_wars_commands"] = raw
	return writeJSONAtomic("persistent", root)
}