package saas

import (
	"context"
	"errors"
	"time"

	"data-terminal-cloud/internal/callmemory"
	"data-terminal-cloud/internal/identity"
	"github.com/jackc/pgx/v5"
)

type HomeOverviewDay struct {
	Date              string `json:"date"`
	ConversationCount int    `json:"conversation_count"`
	DurationMS        int64  `json:"duration_ms"`
}

type HomeOverviewConversation struct {
	ID           string    `json:"id"`
	Source       string    `json:"source"`
	Status       string    `json:"status"`
	StartedAt    time.Time `json:"started_at"`
	EndedAt      time.Time `json:"ended_at"`
	DurationMS   int64     `json:"duration_ms"`
	Summary      string    `json:"summary,omitempty"`
	SummaryState string    `json:"summary_state"`
	SummaryKind  string    `json:"summary_kind,omitempty"`
}

type HomeOverview struct {
	SubjectID          string                    `json:"subject_id"`
	Timezone           string                    `json:"timezone"`
	WeekStart          string                    `json:"week_start"`
	WeekEnd            string                    `json:"week_end"`
	ConversationCount  int                       `json:"conversation_count"`
	TotalDurationMS    int64                     `json:"total_duration_ms"`
	Daily              []HomeOverviewDay         `json:"daily"`
	LatestConversation *HomeOverviewConversation `json:"latest_conversation"`
}

// These are separate session stores, not joins against turns or memories: a
// session contributes once regardless of how many utterances or memories it has.
// DIRECT has no reliable connected_at. Its existing created_at -> ended_at
// duration is retained, but a finalized USER/ASSISTANT utterance must establish
// actual interaction so failed preparations and abandoned leases do not count.
const homeConversationsSQL = `WITH eligible AS (
 SELECT c.public_id AS id,c.id AS internal_id,'conversation'::text AS source,c.status,c.started_at,c.ended_at
 FROM conversation c
 WHERE c.tenant_id=$1::uuid AND c.subject_id=$2::uuid
 AND c.status IN ('COMPLETED','FAILED','EXPIRED') AND c.started_at IS NOT NULL
 AND c.ended_at>c.started_at AND c.ended_at<=$3
 AND NOT EXISTS(SELECT 1 FROM memory_source_suppression ss WHERE ss.subject_id=c.subject_id AND ss.scope='SOURCE_AND_DERIVED'
   AND (ss.source_refs @> jsonb_build_array(jsonb_build_object('conversation_id',c.public_id::text))
     OR ss.source_refs @> jsonb_build_array(jsonb_build_object('conversation_id',c.id::text))
     OR EXISTS(SELECT 1 FROM story_draft sd WHERE sd.conversation_id=c.id AND sd.subject_id=c.subject_id
       AND ss.source_refs @> jsonb_build_array(jsonb_build_object('story_id',sd.public_id::text)))))
 UNION ALL
 SELECT c.id,c.id,'call_memory',c.call_state,c.created_at,c.ended_at
 FROM call_session c
 WHERE c.tenant_id=$1::uuid AND c.subject_id=$2::uuid AND c.budget_snapshot->>'protocol'='DIRECT-CHAT-1'
 AND c.call_state IN ('ENDED','FAILED','CANCELLED') AND c.ended_at>c.created_at AND c.ended_at<=$3
 AND EXISTS(SELECT 1 FROM call_utterance u WHERE u.session_id=c.id AND u.speaker IN ('USER','ASSISTANT')
   AND regexp_replace(u.text_content,'[[:space:]]','','g') NOT IN ('','[deleted]'))
 AND NOT EXISTS(SELECT 1 FROM memory_source_suppression ss WHERE ss.subject_id=c.subject_id AND ss.scope='SOURCE_AND_DERIVED'
   AND ss.source_refs @> jsonb_build_array(jsonb_build_object('session_id',c.id::text)))
), latest AS (SELECT source,id FROM eligible ORDER BY started_at DESC,id DESC,source DESC LIMIT 1)
SELECT e.id::text,e.internal_id::text,e.source,e.status,e.started_at,e.ended_at
FROM eligible e WHERE (e.started_at >= $4 AND e.started_at < $5)
 OR EXISTS(SELECT 1 FROM latest l WHERE l.source=e.source AND l.id=e.id)
ORDER BY e.started_at DESC,e.id DESC,e.source DESC`

// Home calendars use the product timezone even for historical profiles that
// store another timezone. This changes presentation boundaries, not the profile.
func homeCalendarWeek(now time.Time) (time.Time, time.Time, error) {
	location, err := time.LoadLocation("Asia/Shanghai")
	if err != nil {
		return time.Time{}, time.Time{}, err
	}
	local := now.In(location)
	start := time.Date(local.Year(), local.Month(), local.Day(), 0, 0, 0, 0, location)
	start = start.AddDate(0, 0, -(int(start.Weekday())+6)%7)
	return start, start.AddDate(0, 0, 7), nil
}

func (s *Service) SubjectHomeOverview(ctx context.Context, principal identity.Principal, subjectPublicID string) (HomeOverview, error) {
	return s.subjectHomeOverviewAt(ctx, principal, subjectPublicID, time.Now())
}

func (s *Service) subjectHomeOverviewAt(ctx context.Context, principal identity.Principal, subjectPublicID string, now time.Time) (HomeOverview, error) {
	ctx, cancel := context.WithTimeout(ctx, 5*time.Second)
	defer cancel()
	tx, err := s.pool.BeginTx(ctx, pgx.TxOptions{IsoLevel: pgx.RepeatableRead, AccessMode: pgx.ReadOnly})
	if err != nil {
		return HomeOverview{}, err
	}
	defer tx.Rollback(context.Background())
	a, subject, err := resolveSubject(ctx, tx, principal, subjectPublicID, identity.CapabilityConversationRead, false)
	if err != nil {
		return HomeOverview{}, err
	}
	start, end, err := homeCalendarWeek(now)
	if err != nil {
		return HomeOverview{}, err
	}
	location := start.Location()
	result := HomeOverview{SubjectID: subject.ID, Timezone: location.String(), WeekStart: start.Format("2006-01-02"), WeekEnd: end.Format("2006-01-02"), Daily: make([]HomeOverviewDay, 7)}
	dayIndexes := map[string]int{}
	for i := range result.Daily {
		day := start.AddDate(0, 0, i).Format("2006-01-02")
		result.Daily[i].Date = day
		dayIndexes[day] = i
	}
	rows, err := tx.Query(ctx, homeConversationsSQL, a.tenantID, a.subjectID, now, start, end)
	if err != nil {
		return HomeOverview{}, err
	}
	var latestInternalID string
	for rows.Next() {
		var item HomeOverviewConversation
		var internalID string
		if err = rows.Scan(&item.ID, &internalID, &item.Source, &item.Status, &item.StartedAt, &item.EndedAt); err != nil {
			rows.Close()
			return HomeOverview{}, err
		}
		item.DurationMS = item.EndedAt.Sub(item.StartedAt).Milliseconds()
		item.SummaryState = "UNAVAILABLE"
		if result.LatestConversation == nil {
			result.LatestConversation = &item
			latestInternalID = internalID
		}
		// Entire duration belongs to the local start date, including midnight
		// crossings. AddDate above preserves calendar weeks through DST.
		if i, ok := dayIndexes[item.StartedAt.In(location).Format("2006-01-02")]; ok {
			result.Daily[i].ConversationCount++
			result.Daily[i].DurationMS += item.DurationMS
			result.ConversationCount++
			result.TotalDurationMS += item.DurationMS
		}
	}
	err = rows.Err()
	rows.Close()
	if err != nil {
		return HomeOverview{}, err
	}
	if result.LatestConversation != nil {
		grant, grantErr := callmemory.ResolveAccess(ctx, tx, principal, subjectPublicID, false)
		if grantErr == nil {
			err = s.homeConversationSummary(ctx, tx, a.subjectID, latestInternalID, grant, result.LatestConversation)
			if err != nil {
				return HomeOverview{}, err
			}
		} else {
			var denied *callmemory.Error
			if !errors.As(grantErr, &denied) || denied.Status != 403 {
				return HomeOverview{}, grantErr
			}
		}
	}
	return result, tx.Commit(ctx)
}

func (s *Service) homeConversationSummary(ctx context.Context, tx pgx.Tx, subject, id string, grant callmemory.Access, item *HomeOverviewConversation) error {
	if item.Source == "call_memory" {
		var allowed, hasUser, hasAssistant bool
		var transcript, state, lastError string
		err := tx.QueryRow(ctx, `SELECT c.memory_mode<>'OFF' AND managed_call_memory_authorized(c.subject_id)
 AND c.privacy_epoch=COALESCE(mus.privacy_epoch,0),c.transcript_state,COALESCE(j.state,''),COALESCE(j.last_error,''),
 EXISTS(SELECT 1 FROM call_utterance u WHERE u.session_id=c.id AND u.speaker='USER' AND regexp_replace(u.text_content,'[[:space:]]','','g') NOT IN ('','[deleted]')),
 EXISTS(SELECT 1 FROM call_utterance u WHERE u.session_id=c.id AND u.speaker='ASSISTANT' AND regexp_replace(u.text_content,'[[:space:]]','','g') NOT IN ('','[deleted]'))
 FROM call_session c LEFT JOIN memory_user_state mus ON mus.subject_id=c.subject_id
 LEFT JOIN call_memory_sync j ON j.session_id=c.id AND j.transcript_revision=c.transcript_revision
 WHERE c.id=$1::uuid AND c.subject_id=$2::uuid`, id, subject).Scan(&allowed, &transcript, &state, &lastError, &hasUser, &hasAssistant)
		if err != nil {
			return err
		}
		if !allowed {
			return nil
		}
		// A current, active, normal memory from this exact session is a short
		// memory recap, not a synthesized whole-conversation summary.
		err = tx.QueryRow(ctx, `SELECT mv.content FROM managed_memory_origin o
 JOIN curated_memory cm ON cm.id=o.memory_id AND cm.subject_id=o.subject_id
 JOIN memory_version mv ON mv.id=cm.current_version_id AND mv.memory_id=cm.id
 WHERE o.subject_id=$1::uuid AND o.session_id=$2::uuid AND cm.status='ACTIVE' AND cm.sensitivity='normal'
 AND NOT EXISTS(SELECT 1 FROM memory_source_suppression ss WHERE ss.subject_id=cm.subject_id AND ss.source_refs @> mv.source_refs)
 ORDER BY cm.created_at DESC,cm.public_id DESC LIMIT 1`, subject, id).Scan(&item.Summary)
		if err == nil {
			item.SummaryState = "READY"
			item.SummaryKind = "memory"
			return nil
		}
		if !errors.Is(err, pgx.ErrNoRows) {
			return err
		}
		switch {
		case transcript == "DRAINING" || transcript == "COLLECTING":
			item.SummaryState = "PROCESSING"
		case !hasUser || !hasAssistant:
			item.SummaryState = "INSUFFICIENT_TRANSCRIPT"
		case lastError != "":
			item.SummaryState = "SYNC_FAILED"
		case state == "SYNCED" || state == "SKIPPED":
			item.SummaryState = "NO_SUMMARY"
		default:
			item.SummaryState = "PROCESSING"
		}
		return nil
	}
	// Legacy summaries have no sensitivity classification; only a reader with
	// sensitive access may see them. Metadata permission alone never exposes text.
	if !grant.Sensitive {
		return nil
	}
	var allowed, hasUser bool
	var jobState string
	err := tx.QueryRow(ctx, `SELECT c.retention_mode<>'none'
 AND EXISTS(SELECT 1 FROM consent_record cr WHERE cr.subject_id=c.subject_id AND cr.consent_type='transcript_storage' AND cr.withdrawn_at IS NULL AND (cr.expires_at IS NULL OR cr.expires_at>now()))
 AND EXISTS(SELECT 1 FROM consent_record cr WHERE cr.subject_id=c.subject_id AND cr.consent_type='story_extraction' AND cr.withdrawn_at IS NULL AND (cr.expires_at IS NULL OR cr.expires_at>now())),
 EXISTS(SELECT 1 FROM conversation_turn ct WHERE ct.conversation_id=c.id AND ct.speaker='subject' AND regexp_replace(ct.final_text,'[[:space:]]','','g') NOT IN ('','[deleted]')),
 COALESCE((SELECT o.status FROM outbox_event o WHERE o.aggregate_id=c.id AND o.event_type='conversation.content_extraction_requested' ORDER BY o.created_at DESC,o.id DESC LIMIT 1),'')
 FROM conversation c WHERE c.id=$1::uuid AND c.subject_id=$2::uuid`, id, subject).Scan(&allowed, &hasUser, &jobState)
	if err != nil {
		return err
	}
	if !allowed {
		return nil
	}
	var state string
	err = tx.QueryRow(ctx, `SELECT content,status FROM conversation_summary WHERE subject_id=$1::uuid AND conversation_id=$2::uuid AND summary_type='conversation_summary' AND status<>'SUPERSEDED' ORDER BY generation_version DESC LIMIT 1`, subject, id).Scan(&item.Summary, &state)
	if err != nil && !errors.Is(err, pgx.ErrNoRows) {
		return err
	}
	if err == nil && state == "READY" {
		item.SummaryState = "READY"
		item.SummaryKind = "conversation_summary"
		return nil
	}
	item.Summary = ""
	switch {
	case !hasUser:
		item.SummaryState = "INSUFFICIENT_TRANSCRIPT"
	case state == "FAILED" || jobState == "dead":
		item.SummaryState = "SYNC_FAILED"
	case state == "PROCESSING" || jobState == "pending" || jobState == "processing":
		item.SummaryState = "PROCESSING"
	default:
		item.SummaryState = "NO_SUMMARY"
	}
	return nil
}