package taskcenter

import (
	"context"
	"crypto/sha1"
	"encoding/hex"
	"errors"
	"fmt"
	"net/http"
	"strconv"
	"strings"
	"time"

	"chatapp3-golang/internal/integration"
	"chatapp3-golang/internal/model"
	"chatapp3-golang/internal/utils"

	"gorm.io/gorm"
)

// ListTasks 返回 App 任务列表，字段兼容旧 Flutter 模型。
func (s *Service) ListTasks(ctx context.Context, user AuthUser) ([]AppTaskItem, error) {
	sysOrigin := s.normalizeSysOrigin(user.SysOrigin)
	bundle, err := s.loadEnabledBundle(ctx, sysOrigin)
	if err != nil {
		return nil, err
	}
	if bundle == nil {
		return []AppTaskItem{}, nil
	}

	result := make([]AppTaskItem, 0, len(bundle.Tasks))
	for _, task := range bundle.Tasks {
		cycleKey := currentCycleKey(task.TaskCategory, bundle.Location, time.Now())
		progress, exists, err := s.loadProgress(ctx, sysOrigin, user.UserID, task.ID, cycleKey)
		if err != nil {
			return nil, err
		}
		if task.TaskCategory == TaskCategoryNewbie && exists && progress.RewardCollected {
			continue
		}

		completedValue := int64(0)
		rewardCollected := 0
		if exists {
			completedValue = progress.CompletedValue
			if progress.RewardCollected {
				rewardCollected = 1
			}
		}
		taskStatus := 0
		if completedValue >= task.TargetValue {
			taskStatus = 1
		}
		result = append(result, AppTaskItem{
			TaskType:          appTaskType(task.TaskCategory),
			TaskName:          task.TaskName,
			TaskDesc:          task.TaskDesc,
			JumpPage:          resolveJumpPage(task),
			ConditionType:     task.ConditionType,
			SortOrder:         task.SortOrder,
			TaskID:            task.ID,
			TaskStatus:        taskStatus,
			Cover:             task.Cover,
			TaskIcon:          task.TaskIcon,
			ConditionValue:    task.ConditionType,
			CompletedValue:    completedValue,
			IsRewardCollected: rewardCollected,
			TargetValue:       task.TargetValue,
			Quantity:          task.RewardGold,
		})
	}
	return result, nil
}

// ClaimableCount 返回可领取任务数量。
func (s *Service) ClaimableCount(ctx context.Context, user AuthUser) (*ClaimableCountResponse, error) {
	tasks, err := s.ListTasks(ctx, user)
	if err != nil {
		return nil, err
	}
	count := 0
	for _, task := range tasks {
		if task.TaskStatus == 1 && task.IsRewardCollected == 0 {
			count++
		}
	}
	return &ClaimableCountResponse{Count: count}, nil
}

// Claim 领取任务奖励。
func (s *Service) Claim(ctx context.Context, user AuthUser, taskID int64) (bool, error) {
	if taskID <= 0 {
		return false, NewAppError(http.StatusBadRequest, "invalid_task_id", "taskId is required")
	}
	sysOrigin := s.normalizeSysOrigin(user.SysOrigin)
	bundle, err := s.loadEnabledBundle(ctx, sysOrigin)
	if err != nil {
		return false, err
	}
	if bundle == nil {
		return false, NewAppError(http.StatusNotFound, "task_center_not_configured", "task center is not configured")
	}

	var task model.TaskCenterTaskConfig
	found := false
	for _, candidate := range bundle.Tasks {
		if candidate.ID == taskID {
			task = candidate
			found = true
			break
		}
	}
	if !found {
		return false, NewAppError(http.StatusNotFound, "task_not_found", "task not found")
	}
	cycleKey := currentCycleKey(task.TaskCategory, bundle.Location, time.Now())
	progress, exists, err := s.loadProgress(ctx, sysOrigin, user.UserID, task.ID, cycleKey)
	if err != nil {
		return false, err
	}
	if !exists || progress.CompletedValue < task.TargetValue {
		return false, NewAppError(http.StatusBadRequest, "task_not_completed", "task is not completed")
	}
	if progress.RewardCollected {
		return true, nil
	}

	walletEventID := buildWalletEventID(sysOrigin, user.UserID, task.TaskCode, cycleKey)
	if err := s.dispatchClaimGold(ctx, sysOrigin, user.UserID, task, walletEventID); err != nil {
		_ = s.saveClaimRecord(ctx, task, progress, walletEventID, ClaimStatusFailed, err.Error(), nil)
		return false, err
	}

	now := time.Now()
	if err := s.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		if err := s.saveClaimRecordTx(tx, task, progress, walletEventID, ClaimStatusSuccess, "", &now); err != nil {
			return err
		}
		return tx.Model(&model.TaskCenterUserProgress{}).
			Where("id = ?", progress.ID).
			Updates(map[string]any{
				"status":           TaskStatusClaimed,
				"reward_collected": true,
				"claimed_at":       now,
				"update_time":      now,
			}).Error
	}); err != nil {
		return false, err
	}
	return true, nil
}

func (s *Service) dispatchClaimGold(ctx context.Context, sysOrigin string, userID int64, task model.TaskCenterTaskConfig, walletEventID string) error {
	if task.RewardGold <= 0 {
		return nil
	}
	if s.java == nil {
		return NewAppError(http.StatusBadGateway, "wallet_gateway_missing", "wallet gateway is not configured")
	}
	exists, err := s.java.ExistsGoldEvent(ctx, walletEventID)
	if err != nil {
		return NewAppError(http.StatusBadGateway, "wallet_event_check_failed", err.Error())
	}
	if exists {
		return nil
	}
	if err := s.java.ChangeGoldBalance(ctx, integration.GoldReceiptCommand{
		ReceiptType:     "INCOME",
		UserID:          userID,
		SysOrigin:       sysOrigin,
		EventID:         walletEventID,
		Remark:          fmt.Sprintf("taskCode=%s cycleKey=%s", task.TaskCode, currentCycleKey(task.TaskCategory, s.location, time.Now())),
		Amount:          integration.NewPennyAmountPayloadFromDollar(task.RewardGold),
		CloseDelayAsset: false,
		OpUserType:      "APP",
		Origin:          "DAILY_TASK",
	}); err != nil {
		return NewAppError(http.StatusBadGateway, "wallet_change_failed", err.Error())
	}
	return nil
}

func (s *Service) saveClaimRecord(ctx context.Context, task model.TaskCenterTaskConfig, progress model.TaskCenterUserProgress, walletEventID string, status string, failureReason string, claimedAt *time.Time) error {
	return s.db.WithContext(ctx).Transaction(func(tx *gorm.DB) error {
		return s.saveClaimRecordTx(tx, task, progress, walletEventID, status, failureReason, claimedAt)
	})
}

func (s *Service) saveClaimRecordTx(tx *gorm.DB, task model.TaskCenterTaskConfig, progress model.TaskCenterUserProgress, walletEventID string, status string, failureReason string, claimedAt *time.Time) error {
	now := time.Now()
	var row model.TaskCenterClaimRecord
	err := tx.Where("wallet_event_id = ?", walletEventID).First(&row).Error
	if errors.Is(err, gorm.ErrRecordNotFound) {
		id, idErr := utils.NextID()
		if idErr != nil {
			return idErr
		}
		row = model.TaskCenterClaimRecord{
			ID:            id,
			SysOrigin:     progress.SysOrigin,
			UserID:        progress.UserID,
			TaskID:        task.ID,
			TaskCode:      task.TaskCode,
			TaskName:      task.TaskName,
			TaskCategory:  task.TaskCategory,
			CycleKey:      progress.CycleKey,
			RewardGold:    task.RewardGold,
			WalletEventID: walletEventID,
			CreateTime:    now,
		}
	} else if err != nil {
		return err
	}
	row.Status = status
	row.FailureReason = strings.TrimSpace(failureReason)
	row.ClaimedAt = claimedAt
	row.UpdateTime = now
	return tx.Save(&row).Error
}

type taskCenterBundle struct {
	Config   model.TaskCenterConfig
	Tasks    []model.TaskCenterTaskConfig
	Location *time.Location
}

func (s *Service) loadEnabledBundle(ctx context.Context, sysOrigin string) (*taskCenterBundle, error) {
	var configRow model.TaskCenterConfig
	err := s.db.WithContext(ctx).Where("sys_origin = ?", sysOrigin).First(&configRow).Error
	if errors.Is(err, gorm.ErrRecordNotFound) {
		return nil, nil
	}
	if err != nil {
		return nil, err
	}
	if !configRow.Enabled {
		return nil, nil
	}
	location := s.location
	if parsed, parseErr := time.LoadLocation(normalizeTimezone(configRow.Timezone, s.defaultTimezone())); parseErr == nil {
		location = parsed
	}

	var tasks []model.TaskCenterTaskConfig
	if err := s.db.WithContext(ctx).
		Where("config_id = ? AND enabled = ?", configRow.ID, true).
		Order("sort_order asc, id asc").
		Find(&tasks).Error; err != nil {
		return nil, err
	}
	return &taskCenterBundle{Config: configRow, Tasks: tasks, Location: location}, nil
}

func (s *Service) loadProgress(ctx context.Context, sysOrigin string, userID int64, taskID int64, cycleKey string) (model.TaskCenterUserProgress, bool, error) {
	var row model.TaskCenterUserProgress
	err := s.db.WithContext(ctx).
		Where("sys_origin = ? AND user_id = ? AND task_id = ? AND cycle_key = ?", sysOrigin, userID, taskID, cycleKey).
		First(&row).Error
	if errors.Is(err, gorm.ErrRecordNotFound) {
		return model.TaskCenterUserProgress{}, false, nil
	}
	if err != nil {
		return model.TaskCenterUserProgress{}, false, err
	}
	return row, true, nil
}

func appTaskType(category string) int {
	if normalizeCategory(category) == TaskCategoryDaily {
		return 0
	}
	return 1
}

func resolveJumpPage(task model.TaskCenterTaskConfig) string {
	jumpPage := strings.TrimSpace(task.JumpPage)
	if jumpPage != "" {
		return jumpPage
	}
	if isRechargeTask(task) {
		return defaultRechargeJumpPage
	}
	switch normalizeJumpType(task.JumpType) {
	case JumpTypeRechargeInApp:
		return defaultRechargeJumpPage
	case "ROOM_RANDOM", "ROOM_RANDOM_WITH_MIC":
		return "/room"
	case "NONE":
		return ""
	default:
		return jumpPage
	}
}

func isRechargeTask(task model.TaskCenterTaskConfig) bool {
	return strings.EqualFold(strings.TrimSpace(task.ConditionType), EventTypeRechargeGold)
}

func buildWalletEventID(sysOrigin string, userID int64, taskCode string, cycleKey string) string {
	normalizedSysOrigin := compactWalletEventPart(sysOrigin, 8)
	if normalizedSysOrigin == "" {
		normalizedSysOrigin = "SYS"
	}
	raw := strings.Join([]string{
		strings.ToUpper(strings.TrimSpace(sysOrigin)),
		strconv.FormatInt(userID, 10),
		strings.ToUpper(strings.TrimSpace(taskCode)),
		strings.TrimSpace(cycleKey),
	}, "|")
	sum := sha1.Sum([]byte(raw))
	return fmt.Sprintf("TC:%s:%s:%s", normalizedSysOrigin, strconv.FormatInt(userID, 36), hex.EncodeToString(sum[:])[:16])
}

func compactWalletEventPart(value string, maxLen int) string {
	value = strings.ToUpper(strings.TrimSpace(value))
	if maxLen <= 0 {
		return ""
	}
	var builder strings.Builder
	for _, char := range value {
		if (char >= 'A' && char <= 'Z') || (char >= '0' && char <= '9') {
			builder.WriteRune(char)
			if builder.Len() >= maxLen {
				break
			}
		}
	}
	return builder.String()
}