package diagnostics

import (
	"context"
	"encoding/json"
	"sort"
	"strings"
	"time"
	_ "time/tzdata"

	"data-terminal-cloud/internal/audit"
	"data-terminal-cloud/internal/idempotency"
	"data-terminal-cloud/internal/identity"

	"github.com/google/uuid"
	"github.com/jackc/pgx/v5"
)

type PilotDailySnapshotInput struct {
	CandidateVersion string `json:"candidate_version"`
	BuildDigest      string `json:"build_digest"`
	LocalDate        string `json:"local_date"`
	Timezone         string `json:"timezone"`
	Reason           string `json:"reason"`
}

type PilotDeviceState struct {
	Bound             int64 `json:"bound"`
	Eligible          int64 `json:"eligible"`
	Quarantined       int64 `json:"quarantined"`
	Revoked           int64 `json:"revoked"`
	Online            int64 `json:"online"`
	Offline           int64 `json:"offline"`
	ReportedDuringDay int64 `json:"reported_during_day"`
}

type PilotCountByStatus struct {
	Status string `json:"status"`
	Count  int64  `json:"count"`
}

type PilotConversationState struct {
	Total    int64                `json:"total"`
	Statuses []PilotCountByStatus `json:"statuses"`
}

type PilotProviderState struct {
	Provider              string `json:"provider"`
	CurrentStatus         string `json:"current_status"`
	ConsecutiveFailures   int64  `json:"consecutive_failures"`
	FailedEventsDuringDay int64  `json:"failed_events_during_day"`
	FailedCallsDuringDay  int64  `json:"failed_calls_during_day"`
	NotificationBacklog   int64  `json:"notification_backlog"`
}

type PilotUploadState struct {
	CreatedDuringDay   int64 `json:"created_during_day"`
	CompletedDuringDay int64 `json:"completed_during_day"`
	FailedDuringDay    int64 `json:"failed_during_day"`
	OpenBatches        int64 `json:"open_batches"`
	PendingSegments    int64 `json:"pending_segments"`
	RejectedSegments   int64 `json:"rejected_segments"`
}

type PilotAlertState struct {
	OpenedDuringDay   int64 `json:"opened_during_day"`
	ResolvedDuringDay int64 `json:"resolved_during_day"`
	Open              int64 `json:"open"`
	HighOpen          int64 `json:"high_open"`
	CriticalOpen      int64 `json:"critical_open"`
}

type PilotCostState struct {
	Currency   string `json:"currency"`
	CostMicros int64  `json:"cost_micros"`
	LineCount  int64  `json:"line_count"`
}

type PilotDailySnapshot struct {
	ID               string                 `json:"id"`
	GeneratedAt      time.Time              `json:"generated_at"`
	TenantID         string                 `json:"tenant_id"`
	CandidateVersion string                 `json:"candidate_version"`
	BuildDigest      string                 `json:"build_digest"`
	LocalDate        string                 `json:"local_date"`
	Timezone         string                 `json:"timezone"`
	WindowStart      time.Time              `json:"window_start"`
	WindowEnd        time.Time              `json:"window_end"`
	RedactionPolicy  string                 `json:"redaction_policy"`
	Devices          PilotDeviceState       `json:"devices"`
	Conversations    PilotConversationState `json:"conversations"`
	Providers        []PilotProviderState   `json:"providers"`
	Uploads          PilotUploadState       `json:"uploads"`
	Alerts           PilotAlertState        `json:"alerts"`
	Costs            []PilotCostState       `json:"costs"`
	Disclaimer       string                 `json:"disclaimer"`
}

var pilotConversationStatuses = []string{"PREPARING", "ROOM_ISSUED", "STARTING_AGENT", "ACTIVE", "STOPPING", "COMPLETED", "FAILED", "EXPIRED"}

func (s *Service) ExportPilotDailySnapshot(ctx context.Context, principal identity.Principal, tenantPublicID, key, requestID string, input PilotDailySnapshotInput) (PilotDailySnapshot, bool, error) {
	normalizePilotDailySnapshotInput(&input)
	_, windowStart, windowEnd, err := validatePilotDailySnapshotInput(input, time.Now().UTC())
	if err != nil {
		return PilotDailySnapshot{}, false, ErrInvalid
	}
	a, err := s.resolveActor(ctx, principal, tenantPublicID, "ops_operator", "ops_admin")
	if err != nil {
		return PilotDailySnapshot{}, false, err
	}
	requestBody, _ := json.Marshal(input)
	result, err := s.idem.Execute(ctx, idempotency.Request{
		TenantID: &a.tenantID, ActorKey: "ops:" + a.userPublicID,
		Scope: "POST /api/v1/ops/diagnostics/pilot-daily-snapshots", Key: key,
		RequestHash: idempotency.Hash(requestBody), ExpiresAfter: 24 * time.Hour,
	}, func(operationContext context.Context, tx pgx.Tx) (idempotency.Result, error) {
		snapshot, buildErr := buildPilotDailySnapshot(operationContext, tx, tenantPublicID, a.tenantID, input, windowStart, windowEnd)
		if buildErr != nil {
			return idempotency.Result{}, buildErr
		}
		if auditErr := s.audit.Record(operationContext, tx, audit.Event{
			TenantID: &a.tenantID, ActorType: "user", ActorPublicID: &a.userPublicID,
			Action: "ops.diagnostics.pilot_daily_snapshot.export", ResourceType: "pilot_daily_snapshot", ResourceID: &snapshot.ID,
			RequestID: requestID, Purpose: input.Reason, Result: "success",
			Detail: map[string]any{"candidate_version": input.CandidateVersion, "build_digest": input.BuildDigest, "local_date": input.LocalDate, "timezone": input.Timezone, "window_start": windowStart, "window_end": windowEnd, "redaction_policy": snapshot.RedactionPolicy},
		}); auditErr != nil {
			return idempotency.Result{}, auditErr
		}
		encoded, _ := json.Marshal(snapshot)
		return idempotency.Result{StatusCode: 201, Body: encoded, ResourceID: &snapshot.ID}, nil
	})
	if err != nil {
		return PilotDailySnapshot{}, false, err
	}
	var snapshot PilotDailySnapshot
	if err = json.Unmarshal(result.Body, &snapshot); err != nil {
		return PilotDailySnapshot{}, false, err
	}
	return snapshot, !result.Replayed, nil
}

func normalizePilotDailySnapshotInput(input *PilotDailySnapshotInput) {
	input.CandidateVersion = strings.TrimSpace(input.CandidateVersion)
	input.BuildDigest = strings.ToLower(strings.TrimSpace(input.BuildDigest))
	input.LocalDate = strings.TrimSpace(input.LocalDate)
	input.Timezone = strings.TrimSpace(input.Timezone)
	input.Reason = strings.TrimSpace(input.Reason)
}

func validatePilotDailySnapshotInput(input PilotDailySnapshotInput, now time.Time) (*time.Location, time.Time, time.Time, error) {
	if !acceptanceCandidatePattern.MatchString(input.CandidateVersion) || !acceptanceDigestPattern.MatchString(input.BuildDigest) || input.LocalDate == "" || input.Timezone == "" || len([]rune(input.Timezone)) > 80 || input.Reason == "" || len([]rune(input.Reason)) > 255 {
		return nil, time.Time{}, time.Time{}, ErrInvalid
	}
	location, err := time.LoadLocation(input.Timezone)
	if err != nil {
		return nil, time.Time{}, time.Time{}, ErrInvalid
	}
	windowStart, err := time.ParseInLocation("2006-01-02", input.LocalDate, location)
	if err != nil || windowStart.Format("2006-01-02") != input.LocalDate {
		return nil, time.Time{}, time.Time{}, ErrInvalid
	}
	today := now.In(location)
	todayStart := time.Date(today.Year(), today.Month(), today.Day(), 0, 0, 0, 0, location)
	if windowStart.After(todayStart) {
		return nil, time.Time{}, time.Time{}, ErrInvalid
	}
	return location, windowStart.UTC(), windowStart.AddDate(0, 0, 1).UTC(), nil
}

func buildPilotDailySnapshot(ctx context.Context, tx pgx.Tx, tenantPublicID, tenantInternalID string, input PilotDailySnapshotInput, windowStart, windowEnd time.Time) (PilotDailySnapshot, error) {
	snapshot := PilotDailySnapshot{
		ID: uuid.NewString(), GeneratedAt: time.Now().UTC(), TenantID: tenantPublicID, CandidateVersion: input.CandidateVersion, BuildDigest: input.BuildDigest, LocalDate: input.LocalDate, Timezone: input.Timezone,
		WindowStart: windowStart, WindowEnd: windowEnd, RedactionPolicy: "ops-pilot-daily-minimal-v1",
		Conversations: PilotConversationState{Statuses: []PilotCountByStatus{}}, Providers: []PilotProviderState{}, Costs: []PilotCostState{},
		Disclaimer: "本快照混合所选自然日的活动统计与生成时刻的当前积压状态，只用于试点运行复盘；不替代原始监控、真实设备体验、财务账单或发布审批。",
	}
	if err := tx.QueryRow(ctx, `WITH bound AS (
		SELECT d.id,d.status,dt.last_reported_at,dps.online
		FROM device_binding db JOIN device d ON d.id=db.device_id AND d.tenant_id=db.tenant_id
		LEFT JOIN device_twin dt ON dt.device_id=d.id AND dt.tenant_id=d.tenant_id
		LEFT JOIN device_presence_state dps ON dps.device_id=d.id AND dps.tenant_id=d.tenant_id
		WHERE db.tenant_id=$1::uuid AND db.unbound_at IS NULL)
		SELECT count(*),count(*) FILTER(WHERE status='registered'),count(*) FILTER(WHERE status='quarantined'),count(*) FILTER(WHERE status='revoked'),
		count(*) FILTER(WHERE status='registered' AND COALESCE(online,false)),count(*) FILTER(WHERE status='registered' AND NOT COALESCE(online,false)),
		count(*) FILTER(WHERE status='registered' AND last_reported_at >= $2 AND last_reported_at < $3) FROM bound`, tenantInternalID, windowStart, windowEnd).Scan(
		&snapshot.Devices.Bound, &snapshot.Devices.Eligible, &snapshot.Devices.Quarantined, &snapshot.Devices.Revoked,
		&snapshot.Devices.Online, &snapshot.Devices.Offline, &snapshot.Devices.ReportedDuringDay,
	); err != nil {
		return PilotDailySnapshot{}, err
	}
	conversationCounts := map[string]int64{}
	rows, err := tx.Query(ctx, `SELECT status,count(*) FROM conversation WHERE tenant_id=$1::uuid AND created_at >= $2 AND created_at < $3 GROUP BY status`, tenantInternalID, windowStart, windowEnd)
	if err != nil {
		return PilotDailySnapshot{}, err
	}
	for rows.Next() {
		var status string
		var count int64
		if err = rows.Scan(&status, &count); err != nil {
			rows.Close()
			return PilotDailySnapshot{}, err
		}
		conversationCounts[status] = count
		snapshot.Conversations.Total += count
	}
	if err = rows.Err(); err != nil {
		rows.Close()
		return PilotDailySnapshot{}, err
	}
	rows.Close()
	for _, status := range pilotConversationStatuses {
		snapshot.Conversations.Statuses = append(snapshot.Conversations.Statuses, PilotCountByStatus{Status: status, Count: conversationCounts[status]})
	}
	rows, err = tx.Query(ctx, `WITH providers AS (
		SELECT provider FROM provider_dependency_state WHERE tenant_id=$1::uuid
		UNION SELECT pe.provider FROM provider_event pe WHERE pe.tenant_id=$1::uuid AND pe.received_at >= $2 AND pe.received_at < $3
		UNION SELECT rt.provider FROM conversation c JOIN rtc_task rt ON rt.conversation_id=c.id WHERE c.tenant_id=$1::uuid AND c.created_at >= $2 AND c.created_at < $3)
		SELECT p.provider,COALESCE(pds.status,'UNKNOWN'),COALESCE(pds.consecutive_failures,0),
		(SELECT count(*) FROM provider_event pe WHERE pe.tenant_id=$1::uuid AND pe.provider=p.provider AND pe.processing_status='failed' AND pe.received_at >= $2 AND pe.received_at < $3),
		(SELECT count(DISTINCT c.id) FROM conversation c
		 JOIN rtc_task rt ON rt.conversation_id=c.id
		 JOIN conversation_state_history csh ON csh.conversation_id=c.id
		 WHERE c.tenant_id=$1::uuid AND rt.provider=p.provider AND csh.to_status='FAILED' AND csh.occurred_at >= $2 AND csh.occurred_at < $3),
		(SELECT count(*) FROM provider_event pe WHERE pe.tenant_id=$1::uuid AND pe.provider=p.provider AND pe.processing_status IN ('pending','failed'))
		FROM providers p LEFT JOIN provider_dependency_state pds ON pds.tenant_id=$1::uuid AND pds.provider=p.provider ORDER BY p.provider`, tenantInternalID, windowStart, windowEnd)
	if err != nil {
		return PilotDailySnapshot{}, err
	}
	for rows.Next() {
		var item PilotProviderState
		if err = rows.Scan(&item.Provider, &item.CurrentStatus, &item.ConsecutiveFailures, &item.FailedEventsDuringDay, &item.FailedCallsDuringDay, &item.NotificationBacklog); err != nil {
			rows.Close()
			return PilotDailySnapshot{}, err
		}
		snapshot.Providers = append(snapshot.Providers, item)
	}
	if err = rows.Err(); err != nil {
		rows.Close()
		return PilotDailySnapshot{}, err
	}
	rows.Close()
	if err = tx.QueryRow(ctx, `SELECT
		count(*) FILTER(WHERE created_at >= $2 AND created_at < $3),
		count(*) FILTER(WHERE completed_at >= $2 AND completed_at < $3),
		count(*) FILTER(WHERE status='FAILED' AND updated_at >= $2 AND updated_at < $3),
		count(*) FILTER(WHERE status IN ('PENDING','UPLOADING','VERIFYING')),
		(SELECT count(*) FROM media_segment WHERE tenant_id=$1::uuid AND status IN ('DECLARED','AUTHORIZED','UPLOADED','VERIFYING')),
		(SELECT count(*) FROM media_segment WHERE tenant_id=$1::uuid AND status='REJECTED')
		FROM upload_batch WHERE tenant_id=$1::uuid`, tenantInternalID, windowStart, windowEnd).Scan(
		&snapshot.Uploads.CreatedDuringDay, &snapshot.Uploads.CompletedDuringDay, &snapshot.Uploads.FailedDuringDay,
		&snapshot.Uploads.OpenBatches, &snapshot.Uploads.PendingSegments, &snapshot.Uploads.RejectedSegments,
	); err != nil {
		return PilotDailySnapshot{}, err
	}
	if err = tx.QueryRow(ctx, `SELECT
		count(*) FILTER(WHERE first_detected_at >= $2 AND first_detected_at < $3),
		count(*) FILTER(WHERE resolved_at >= $2 AND resolved_at < $3),
		count(*) FILTER(WHERE status <> 'RESOLVED'),
		count(*) FILTER(WHERE status <> 'RESOLVED' AND severity='HIGH'),
		count(*) FILTER(WHERE status <> 'RESOLVED' AND severity='CRITICAL')
		FROM alert_incident WHERE tenant_id=$1::uuid`, tenantInternalID, windowStart, windowEnd).Scan(
		&snapshot.Alerts.OpenedDuringDay, &snapshot.Alerts.ResolvedDuringDay, &snapshot.Alerts.Open,
		&snapshot.Alerts.HighOpen, &snapshot.Alerts.CriticalOpen,
	); err != nil {
		return PilotDailySnapshot{}, err
	}
	rows, err = tx.Query(ctx, `SELECT ccl.currency,COALESCE(sum(ccl.cost_micros),0)::bigint,count(*)
		FROM conversation_cost_line ccl JOIN conversation_usage_event cue ON cue.id=ccl.usage_event_id
		WHERE ccl.tenant_id=$1::uuid AND cue.occurred_at >= $2 AND cue.occurred_at < $3
		GROUP BY ccl.currency ORDER BY ccl.currency`, tenantInternalID, windowStart, windowEnd)
	if err != nil {
		return PilotDailySnapshot{}, err
	}
	for rows.Next() {
		var item PilotCostState
		if err = rows.Scan(&item.Currency, &item.CostMicros, &item.LineCount); err != nil {
			rows.Close()
			return PilotDailySnapshot{}, err
		}
		snapshot.Costs = append(snapshot.Costs, item)
	}
	if err = rows.Err(); err != nil {
		rows.Close()
		return PilotDailySnapshot{}, err
	}
	rows.Close()
	sort.Slice(snapshot.Providers, func(i, j int) bool { return snapshot.Providers[i].Provider < snapshot.Providers[j].Provider })
	return snapshot, nil
}