package dnfbridge

import (
	"context"
	"crypto/sha256"
	"fmt"
	"math/rand/v2"
	"sort"
	"strconv"
	"strings"
	"time"

	dnfdungeon "longheng.io/server/internal/modules/dnf/dungeon"
	dnfprofession "longheng.io/server/internal/modules/dnf/profession"
	"longheng.io/server/internal/modules/dnf/progression"
	dnfquest "longheng.io/server/internal/modules/dnf/quest"
	dnfrepo "longheng.io/server/internal/modules/dnf/repository"
	dnfskill "longheng.io/server/internal/modules/dnf/skill"
	"longheng.io/server/internal/modules/dnf/skillcmd"
)

const companionProgressionReceiptPrefix = "companion_progression_receipt_"

// syncCurrentDungeonCompanionProgression mirrors one already committed owner
// event to the account's selected support soldiers. The owner is committed
// first; each support soldier then commits in its own settlement transaction.
// The hashed event receipt makes retries safe without adding a new table.
func (s *Service) syncCurrentDungeonCompanionProgression(
	ctx context.Context,
	session *gameSession,
	eventKey string,
	tables *progression.Tables,
	gain uint32,
	ownerQuest *dnfrepo.QuestRecord,
) {
	if s == nil || session == nil || session.selectedCharacterID == 0 ||
		(strings.TrimSpace(eventKey) == "") || (gain == 0 && ownerQuest == nil) {
		return
	}
	if ctx == nil {
		ctx = context.Background()
	}
	repos, ok := s.repositoryGroup()
	if !ok || repos.CharacterSettlement == nil || repos.Character == nil || repos.Skill == nil || (gain > 0 && tables == nil) {
		s.logGameEvent(session, "game-dungeon-companion-progression-skipped",
			"event_key", eventKey, "reason", "repository_or_progression_unavailable")
		return
	}
	ownerID := strconv.FormatUint(uint64(session.selectedCharacterID), 10)
	accountID := strings.TrimSpace(s.accountIDForSession(session))
	if accountID == "" {
		if owner, found, loadErr := repos.Character.Load(ctx, ownerID); loadErr == nil && found {
			accountID = strings.TrimSpace(owner.AccountID)
		}
	}
	cfg, _, _, err := s.loadCurrentDungeonCompanionConfig(ctx, ownerID, accountID, repos)
	if err != nil {
		s.logGameEvent(session, "game-dungeon-companion-progression-skipped", "event_key", eventKey, "reason", "config_unavailable", "error", err)
		return
	}
	if !cfg.Enabled || !cfg.ProgressionEnabled {
		return
	}
	if accountID == "" {
		return
	}
	// Every quest sync already carries the owner's complete committed quest
	// snapshot. Carry its durable effects too, even when the support soldier's
	// quest rows were copied by an older version and need no further changes.
	var ownerCharacter *dnfrepo.CharacterRecord
	if ownerQuest != nil {
		owner, found, loadErr := repos.Character.Load(ctx, ownerID)
		if loadErr != nil || !found || owner.CharacterID != ownerID ||
			strings.TrimSpace(owner.AccountID) != accountID || ownerQuest.CharacterID != ownerID {
			s.logGameEvent(session, "game-dungeon-companion-progression-skipped",
				"event_key", eventKey, "reason", "committed_owner_unavailable_or_mismatched", "error", loadErr)
			return
		}
		ownerCharacter = &owner
	}
	profiles, skillCatalog, resourceErr := s.currentProfessionResources(ctx)
	if resourceErr != nil {
		// Ordinary synchronization can proceed without automatic learning.
		// A pending profession change requires these resources and aborts that source's
		// settlement below so quest state cannot outpace its durable effects.
		s.logGameEvent(session, "game-dungeon-companion-skill-auto-learn-deferred",
			"event_key", eventKey, "reason", "skill_pvf_unavailable", "error", resourceErr)
		profiles, skillCatalog = nil, nil
	}
	for _, sourceID := range cfg.Sources() {
		if sourceID == ownerID {
			continue
		}
		if identity, online := s.onlineGameSessionCharacterSnapshot(parseCurrentCompanionCharacterID(sourceID)); online && identity.session != session {
			s.logGameEvent(session, "game-dungeon-companion-progression-skipped",
				"source_character_id", sourceID, "event_key", eventKey, "reason", "source_online")
			continue
		}
		deferred, err := s.applyCurrentDungeonCompanionProgression(
			ctx, repos, accountID, sourceID, ownerID+":"+eventKey, tables, gain, ownerQuest,
			ownerCharacter, profiles, skillCatalog,
		)
		if err != nil {
			s.logGameEvent(session, "game-dungeon-companion-progression-failed",
				"source_character_id", sourceID, "event_key", eventKey, "gain", gain, "error", err)
			continue
		}
		if deferred {
			s.logGameEvent(session, "game-dungeon-companion-awakening-deferred",
				"source_character_id", sourceID, "event_key", eventKey,
				"reason", "source_profession_does_not_support_owner_awakening")
		}
		s.logGameEvent(session, "game-dungeon-companion-progression-applied",
			"source_character_id", sourceID, "event_key", eventKey, "gain", gain)
		s.queueCurrentDungeonCompanionProgressionRefresh(session, sourceID)
	}
}

func parseCurrentCompanionCharacterID(raw string) uint16 {
	value, err := strconv.ParseUint(strings.TrimSpace(raw), 10, 16)
	if err != nil || value == 0 {
		return 0
	}
	return uint16(value)
}

func companionProgressionReceiptKey(eventKey string) string {
	hash := sha256.Sum256([]byte(strings.TrimSpace(eventKey)))
	return fmt.Sprintf("%s%x", companionProgressionReceiptPrefix, hash[:])
}

// currentCompanionMonsterExperienceEventKey 为「打怪经验」这笔结算生成一个
// 可重放的稳定事件键。清图回执要等 boss 死才创建，所以这里用**本次副本入场
// 的身份**（入场时间戳 + 种子 + 副本 + 层 + object key）当前缀，避免同一副本
// 的多次进场共用同一份回执、把第二次的经验镜像误判成已完成。
func currentCompanionMonsterExperienceEventKey(runtime *runtimeDungeonState, objectKey uint32) string {
	if runtime == nil {
		return fmt.Sprintf("monster:0:0:0:0:%d", objectKey)
	}
	return fmt.Sprintf("monster:%d:%d:%d:%d:%d", runtime.startedAt.UnixNano(),
		runtime.Seed, runtime.Dungeon.ID, runtime.MazeIndex, objectKey)
}

func (s *Service) applyCurrentDungeonCompanionProgression(
	ctx context.Context,
	repos dnfrepo.Group,
	accountID, sourceID, eventKey string,
	tables *progression.Tables,
	gain uint32,
	ownerQuest *dnfrepo.QuestRecord,
	ownerCharacter *dnfrepo.CharacterRecord,
	profiles *dnfprofession.Profiles,
	skillCatalog *dnfskill.Table,
) (bool, error) {
	if repos.CharacterSettlement == nil {
		return false, dnfrepo.ErrCharacterSettlementTransactionUnavailable
	}
	receiptKey := companionProgressionReceiptKey(eventKey)
	now := time.Now().UTC()
	var awakeningDeferred bool
	err := repos.CharacterSettlement.WithinCharacterSettlement(ctx, sourceID, func(tx dnfrepo.Group) error {
		if tx.Character == nil || tx.Skill == nil {
			return dnfrepo.ErrCharacterSettlementTransactionUnavailable
		}
		character, found, err := tx.Character.Load(ctx, sourceID)
		if err != nil {
			return err
		}
		if !found || character.CharacterID != sourceID || strings.TrimSpace(character.AccountID) != accountID {
			return fmt.Errorf("support soldier character/account mismatch: source=%s", sourceID)
		}
		// Receipts suppress EXP only. A replay must still be able to repair
		// quest effects missed by the previous state-only implementation.
		applyGain := gain > 0 && character.Stats[receiptKey] != 1
		skill, found, err := tx.Skill.Load(ctx, sourceID)
		if err != nil {
			return err
		}
		if !found || skill.CharacterID != sourceID {
			return fmt.Errorf("support soldier skill record missing: source=%s", sourceID)
		}
		character = dnfrepo.CloneCharacter(character)
		skill = dnfrepo.CloneSkill(skill)
		if character.Stats == nil {
			character.Stats = make(map[string]int64)
		}
		// 历史数据自愈：技能记录的 synced_level 可能**超前**于角色等级
		// （GM 改过等级、克隆角色只复制了一半记录等）。实测取证：角色 3
		// level=87 但 skill.synced_level=88，导致下面的
		// PlanSettlementProgressionAtCap 以
		// "dungeon settlement persisted state is invalid" 拒绝整笔镜像，
		// 支援兵于是永远停在 grow_type=0（未觉醒）。
		//
		// 角色等级是权威，把记账字段拉回角色等级即可；技能本体和 SP/TP 都不动。
		// 反向（synced_level 落后）不做静默对齐——那会跳过中间等级的 SP 发放，
		// 宁可报错也不篡改成长账目。
		if skill.Points.SyncedLevel != character.Level {
			if skill.Points.SyncedLevel > character.Level {
				skill.Points.SyncedLevel = character.Level
			} else {
				return fmt.Errorf("support soldier skill synced level behind character: source=%s synced=%d level=%d",
					sourceID, skill.Points.SyncedLevel, character.Level)
			}
		}
		if applyGain {
			experience, present := character.Stats["exp"]
			if !present || experience < 0 || character.Level <= 0 {
				return fmt.Errorf("support soldier progression state invalid: source=%s", sourceID)
			}
			if uint64(experience) > ^uint64(0)>>32 {
				return fmt.Errorf("support soldier experience outside u32: source=%s", sourceID)
			}
			planned, planErr := dnfdungeon.PlanSettlementProgressionAtCap(
				tables, character.Level, uint32(experience), gain,
				skill.Points, progression.CharacterLevelCap,
			)
			if planErr != nil {
				return planErr
			}
			character.Level = planned.Experience.NewLevel
			character.Stats["exp"] = int64(planned.Experience.NewExperience)
			skill.Points = planned.SkillPoints.New
			if planned.Experience.NewLevel != planned.Experience.PreviousLevel {
				if levelStats, statErr := s.characterPVFStatValuesForLevel(character, planned.Experience.NewLevel); statErr == nil {
					for key, value := range levelStats {
						character.Stats[key] = value
					}
				}
			}
		}
		effectsChanged, deferred, err := applyCurrentDungeonCompanionQuestEffects(&character, &skill, ownerCharacter, profiles, skillCatalog)
		if err != nil {
			return err
		}
		awakeningDeferred = deferred
		if profiles != nil && skillCatalog != nil {
			if err := autoLearnCurrentDungeonCompanionSkills(character, &skill, profiles, skillCatalog); err != nil {
				return err
			}
		}
		if applyGain {
			character.Stats[receiptKey] = 1
		}
		if applyGain || effectsChanged {
			character.UpdatedAt = now
			if err := dnfrepo.SaveCharacterFields(ctx, tx.Character, character, dnfrepo.CharacterFieldBase, dnfrepo.CharacterFieldStats); err != nil {
				return err
			}
		}
		skill.UpdatedAt = now
		if err := dnfrepo.SaveSkillFields(ctx, tx.Skill, skill, dnfrepo.SkillFieldSkills, dnfrepo.SkillFieldPoints, dnfrepo.SkillFieldLayouts); err != nil {
			return err
		}
		if ownerQuest != nil {
			if tx.Quest == nil {
				return dnfrepo.ErrCharacterSettlementTransactionUnavailable
			}
			if err := mergeCurrentDungeonCompanionQuest(ctx, tx.Quest, sourceID, *ownerQuest, now); err != nil {
				return err
			}
		}
		return nil
	})
	return awakeningDeferred && err == nil, err
}

// Quest completion and its durable effects share the support soldier's
// settlement transaction. Ordinary item/gold rewards remain suppressed.
// An unchosen class is selected randomly from the source job's PVF branches,
// never copied from the owner. Existing classes are retained, and awakening
// advances that same branch. Jobs without class branches keep branch zero.
func applyCurrentDungeonCompanionQuestEffects(
	character *dnfrepo.CharacterRecord,
	skill *dnfrepo.SkillRecord,
	owner *dnfrepo.CharacterRecord,
	profiles *dnfprofession.Profiles,
	catalog *dnfskill.Table,
) (changed, deferred bool, err error) {
	if owner == nil {
		return false, false, nil
	}
	ownerGrow, sourceGrow := owner.Stats["grow_type"], character.Stats["grow_type"]
	if ownerGrow < 0 || ownerGrow > 255 || sourceGrow < 0 || sourceGrow > 255 {
		return false, false, fmt.Errorf("support soldier grow_type invalid: owner=%d source=%d", ownerGrow, sourceGrow)
	}
	ownerBranch, ownerAwakening := dnfprofession.Decode(byte(ownerGrow))
	branch, sourceAwakening := dnfprofession.Decode(byte(sourceGrow))
	if ownerAwakening > 2 || sourceAwakening > 2 {
		return false, false, fmt.Errorf("support soldier awakening stage invalid: owner=%d source=%d", ownerAwakening, sourceAwakening)
	}
	if character.Stats == nil {
		character.Stats = make(map[string]int64)
	}
	// Retain every existing source bit; only proven owner unlocks are added.
	beforeSlots := character.Stats["ex_equip_slot_stat"]
	ownerSlots := owner.Stats["ex_equip_slot_stat"]
	if ownerSlots < 0 || beforeSlots < 0 {
		return false, false, fmt.Errorf("support soldier equipment slot state invalid")
	}
	if slots := beforeSlots | (ownerSlots & int64(dnfquest.ExEquipSlotAll)); slots != beforeSlots {
		character.Stats["ex_equip_slot_stat"] = slots
		changed = true
	}
	needsClassChange := sourceGrow == 0 && (ownerBranch != 0 || ownerAwakening != 0)
	if !needsClassChange && sourceAwakening >= ownerAwakening {
		return changed, false, nil
	}
	if profiles == nil || catalog == nil {
		return false, false, dnfprofession.ErrSourceRequired
	}
	job, parseErr := strconv.ParseUint(strings.TrimSpace(character.Job), 10, 8)
	if parseErr != nil {
		return false, false, fmt.Errorf("support soldier job invalid: %w", parseErr)
	}
	if needsClassChange {
		if !profiles.SupportsTarget(byte(job), 0) {
			return false, false, fmt.Errorf("%w: support soldier job=%d", dnfprofession.ErrProfileMissing, job)
		}
		choices := make([]dnfprofession.Transition, 0, 4)
		for target := byte(1); target <= 0x0f; target++ {
			transition, planErr := profiles.PlanTransition(byte(job), 0, dnfprofession.Request{
				Kind: dnfprofession.KindClassChange, ChainType: 1, GrowNumber: target, JobChangeQuest: 1,
			})
			if planErr == nil {
				choices = append(choices, transition)
			}
		}
		if len(choices) != 0 {
			transition := choices[rand.IntN(len(choices))]
			updated, skillErr := profiles.ApplySkillTransition(catalog, byte(job), character.Level, transition, *skill, skill.Points)
			if skillErr != nil {
				return false, false, skillErr
			}
			character.Stats["grow_type"] = int64(transition.NewGrowType)
			branch = transition.FirstGrowType
			*skill = updated
			changed = true
		}
	}
	for stage := sourceAwakening + 1; stage <= ownerAwakening; stage++ {
		target, _ := dnfprofession.Encode(branch, stage)
		if !profiles.SupportsTarget(byte(job), target) {
			return changed, true, nil
		}
		request, requestErr := dnfprofession.ParseReward(int(stage)+1, "[awakening type]", []int64{int64(stage)})
		if requestErr != nil {
			return false, false, requestErr
		}
		transition, planErr := profiles.PlanTransition(byte(job), byte(character.Stats["grow_type"]), request)
		if planErr != nil {
			return false, false, planErr
		}
		updated, skillErr := profiles.ApplySkillTransition(catalog, byte(job), character.Level, transition, *skill, skill.Points)
		if skillErr != nil {
			return false, false, skillErr
		}
		character.Stats["grow_type"] = int64(transition.NewGrowType)
		*skill = updated
		changed = true
	}
	return changed, false, nil
}

// autoLearnCurrentDungeonCompanionSkills keeps PVF profession grants and
// fixed-level skills in sync, then spends newly available SP/TP on the first
// level of every newly eligible skill in deterministic PVF order. Existing
// player allocations are preserved; only an unlearned skill can be added.
func autoLearnCurrentDungeonCompanionSkills(
	character dnfrepo.CharacterRecord,
	record *dnfrepo.SkillRecord,
	profiles *dnfprofession.Profiles,
	catalog *dnfskill.Table,
) error {
	if record == nil || profiles == nil || catalog == nil {
		return nil
	}
	jobValue, err := strconv.ParseUint(strings.TrimSpace(character.Job), 10, 8)
	if err != nil {
		return err
	}
	job := byte(jobValue)
	growType := byte(numericCharacterStatValue(character, "grow_type"))
	first, awakening := dnfprofession.Decode(growType)
	if record.Skills == nil {
		record.Skills = make(map[int64]dnfrepo.SkillState)
	}
	if grants, ok := profiles.FreeGrantsAtCharacterLevel(catalog, job, first, awakening, character.Level); ok {
		for _, grant := range grants {
			state := record.Skills[int64(grant.SkillID)]
			if state.Level < grant.Level {
				state.Level = grant.Level
				state.Enabled = true
				record.Skills[int64(grant.SkillID)] = state
			}
		}
	}
	definitions := catalog.SkillsForJob(job)
	sort.SliceStable(definitions, func(i, j int) bool {
		if definitions[i].RequiredLevel != definitions[j].RequiredLevel {
			return definitions[i].RequiredLevel < definitions[j].RequiredLevel
		}
		return definitions[i].ID < definitions[j].ID
	})
	for pass := 0; pass < len(definitions); pass++ {
		changed := false
		for _, definition := range definitions {
			if definition.RequiredLevel > character.Level || !definition.SupportsCharacterGrowth(int(growType)) {
				continue
			}
			state := record.Skills[int64(definition.ID)]
			if state.Level > 0 || skillPrerequisitesBrokenForCompanion(record.Skills, definition) {
				continue
			}
			maximum := definition.MaximumLevelForCharacterGrowth(int(growType))
			if maximum == 0 {
				continue
			}
			cost := definition.LevelCost(0)
			if cost < 0 {
				continue
			}
			if definition.IsTPSkill() {
				if record.Points.RemainingTP < cost {
					continue
				}
				record.Points.RemainingTP -= cost
			} else {
				if record.Points.RemainingSP < cost {
					continue
				}
				record.Points.RemainingSP -= cost
			}
			record.Skills[int64(definition.ID)] = dnfrepo.SkillState{Level: 1, Enabled: true}
			changed = true
		}
		if !changed {
			break
		}
	}
	existing := dnfrepo.SkillLayout(nil)
	if record.Layouts != nil {
		existing = record.Layouts[0]
	}
	layout, err := skillcmd.BuildCurrentSkillLayout(catalog, job, 0, record.Skills, existing)
	if err != nil {
		return err
	}
	if record.Layouts == nil {
		record.Layouts = make(map[int]dnfrepo.SkillLayout)
	}
	record.Layouts[0] = layout
	return nil
}

func skillPrerequisitesBrokenForCompanion(states map[int64]dnfrepo.SkillState, definition dnfskill.Skill) bool {
	for _, prerequisite := range definition.Prerequisites {
		if states[int64(prerequisite.SkillID)].Level < prerequisite.Level {
			return true
		}
	}
	return false
}

func mergeCurrentDungeonCompanionQuest(
	ctx context.Context,
	repo dnfrepo.QuestRepository,
	sourceID string,
	owner dnfrepo.QuestRecord,
	now time.Time,
) error {
	current, found, err := repo.Load(ctx, sourceID)
	if err != nil {
		return err
	}
	if !found {
		current = dnfrepo.QuestRecord{CharacterID: sourceID}
	}
	current = dnfrepo.CloneQuest(current)
	changedStates := mergeCompanionQuestStates(&current.States, owner.States)
	changedProgress := mergeCompanionQuestStates(&current.Progress, owner.Progress)
	if !changedStates && !changedProgress {
		return nil
	}
	current.CharacterID = sourceID
	current.UpdatedAt = now
	fields := make([]dnfrepo.QuestField, 0, 2)
	if changedStates {
		fields = append(fields, dnfrepo.QuestFieldStates)
	}
	if changedProgress {
		fields = append(fields, dnfrepo.QuestFieldProgress)
	}
	return dnfrepo.SaveQuestFields(ctx, repo, current, fields...)
}

func mergeCompanionQuestStates(target *map[int64]dnfrepo.QuestState, source map[int64]dnfrepo.QuestState) bool {
	if target == nil || len(source) == 0 {
		return false
	}
	if *target == nil {
		*target = make(map[int64]dnfrepo.QuestState)
	}
	changed := false
	for id, state := range source {
		if !isCompanionQuestCompletedStatus(state.Status) {
			continue
		}
		previous, exists := (*target)[id]
		if exists && isCompanionQuestCompletedStatus(previous.Status) {
			continue
		}
		// Copy completion semantics, never the owner's reward receipt or active
		// objectives. The source receives EXP separately and cannot claim these
		// rewards again under the owner's character/account receipt.
		extra := map[string]string{
			"reward_state": "granted", "auto_completed": "true",
			"auto_complete_reason": "companion_progression",
		}
		for _, key := range []string{"pvf_path", "quest_type", "clear_flag"} {
			if value := state.Extra[key]; value != "" {
				extra[key] = value
			}
		}
		state.Extra = extra
		state.ProgressValue, state.RewardSelectIndex, state.Multiplier = 0, 0, 0
		(*target)[id] = state
		changed = true
	}
	return changed
}

func isCompanionQuestCompletedStatus(status string) bool {
	status = strings.ToLower(strings.TrimSpace(status))
	status = strings.ReplaceAll(status, "_", "")
	status = strings.ReplaceAll(status, "-", "")
	status = strings.ReplaceAll(status, " ", "")
	switch status {
	case "complete", "completed", "cleared", "finished", "done":
		return true
	default:
		return false
	}
}