package gameserver

import (
	"fmt"

	"gac-hkrpg-go/internal/common"
	goproto "gac-hkrpg-go/protocol/proto"
	"google.golang.org/protobuf/proto"
)

// Shared read path for entry and GetData. It never adopts a revision into a
// session or writes persistent; callers choose when a validated view becomes
// their current session revision.
func readCurrencyWarsData(catalog *common.CurrencyWarsCatalog) (*goproto.GridFightGetDataScRsp, uint64, error) {
	if catalog == nil {
		return nil, 0, fmt.Errorf("CW catalog is missing")
	}
	cfg, err := common.LoadRuntimeConfig()
	if err != nil {
		return nil, 0, err
	}
	snapshot, err := common.ReadCurrencyWarsSnapshot(cfg.PlayerUID, catalog.ClientVersion, catalog.Provenance.GameAssemblySHA256)
	if err != nil {
		return nil, 0, err
	}
	if snapshot == nil {
		return nil, 0, nil
	}
	var saved goproto.GridFightGetDataScRsp
	if err := proto.Unmarshal(snapshot.WireData, &saved); err != nil {
		return nil, 0, fmt.Errorf("decode saved CW protocol: %w", err)
	}
	if err := validateCurrencyWarsSavedData(&saved, catalog); err != nil {
		return nil, 0, err
	}
	return &saved, snapshot.Revision, nil
}

// Validate known metadata prerequisites before restoring a saved response.
// Full run validation belongs to the gameplay state machine, which is still
// being implemented. Entry and captured initial-choice handlers commit only
// their validated phases; this is not full gameplay/resume validation.
func validateCurrencyWarsSavedData(data *goproto.GridFightGetDataScRsp, catalog *common.CurrencyWarsCatalog) error {
	if data == nil || catalog == nil || data.Retcode != 0 || data.LFLCDNGALME == nil {
		return fmt.Errorf("saved CW response is missing metadata or contains an error")
	}
	meta := data.LFLCDNGALME
	if meta.PKELAIPIHMF == nil || meta.PKELAIPIHMF.MHFHLBHFIBC == nil || meta.HFPEJIDDDJG == nil {
		return fmt.Errorf("saved CW permanent/season state is incomplete")
	}
	season := meta.HFPEJIDDDJG
	if season.ADFEKPNIFOJ != catalog.ActiveSeasonID || season.GEGMHOMNBDG != catalog.ActiveSubSeasonID || season.Exp == nil || season.MHFHLBHFIBC == nil || season.NLENPEPIHAC == nil {
		return fmt.Errorf("saved CW season state differs from captured active season")
	}
	division, ok := catalog.Division(season.DivisionId)
	if !ok || division.SeasonID != catalog.ActiveSeasonID {
		return fmt.Errorf("saved CW division is not in active season")
	}
	book := season.NLENPEPIHAC
	if book.DNEGDNEBJMB == nil || book.NIOAIKLPACM == nil || book.EECJFCNKKMB == nil || book.KJIJEGAHLGB == nil || book.NNIJIFGJJJA == nil || book.JLFANEOAHOC == nil || book.EJHDGLHCNLH == nil || book.PJBIPMKACOF == nil {
		return fmt.Errorf("saved CW handbook containers are incomplete")
	}
	if run := data.DHFOFLFCLAH; run != nil {
		// Native Start/GetData captures establish LJNGPCKPJLF as Season.
		// MPJPLKKJNGE is not a required season identity; it can be zero.
		if run.UniqueId == 0 || run.LJNGPCKPJLF != catalog.ActiveSeasonID || run.DivisionId == 0 {
			return fmt.Errorf("saved CW active run identity is incomplete")
		}
		if d, ok := catalog.Division(run.DivisionId); !ok || d.SeasonID != run.LJNGPCKPJLF {
			return fmt.Errorf("saved CW run division differs from its season")
		}
	}
	return nil
}

// saveCurrencyWarsData must be called only after a validated CW state-machine
// transition, under the session state lock. It does not alter adventure data.
func (s *Session) saveCurrencyWarsData(data *goproto.GridFightGetDataScRsp, catalog *common.CurrencyWarsCatalog) error {
	if err := validateCurrencyWarsSavedData(data, catalog); err != nil {
		return err
	}
	cfg, err := common.LoadRuntimeConfig()
	if err != nil {
		return err
	}
	wire, err := proto.Marshal(data)
	if err != nil {
		return err
	}
	next := common.NewCurrencyWarsSnapshot(cfg.PlayerUID, catalog.ClientVersion, catalog.Provenance.GameAssemblySHA256, wire)
	revision, err := common.CommitCurrencyWarsSnapshot(s.currencyWarsRevision, next)
	if err != nil {
		return err
	}
	s.currencyWarsRevision = revision
	return nil
}