package postgres

import (
	"context"
	"fmt"
	"time"

	"git.cin.su/m/Assistant/contracts/epistemics"
	"github.com/jackc/pgx/v5/pgxpool"
)

type EpistemicsRepository struct{ pool *pgxpool.Pool }

func OpenEpistemics(ctx context.Context, config ContinuityConfig) (*EpistemicsRepository, error) {
	pool, err := openPool(ctx, config)
	if err != nil {
		return nil, err
	}
	return &EpistemicsRepository{pool: pool}, nil
}

func (r *EpistemicsRepository) Close() { r.pool.Close() }

func (r *EpistemicsRepository) SaveSystemExpectation(ctx context.Context, value epistemics.SystemExpectation) error {
	_, err := r.pool.Exec(ctx, `INSERT INTO epistemics.system_expectations (
		expectation_id, original_intent_id, source_utterance_id, expected_outcome, expected_effect,
		confidence_millis, evidence_basis, recorded_at_unix_millis)
		VALUES ($1,$2,$3,$4,$5,$6,$7,$8) ON CONFLICT DO NOTHING`,
		value.ID, value.OriginalIntentID, value.SourceUtteranceID, value.ExpectedOutcome, value.ExpectedEffect,
		value.ConfidenceMillis, value.EvidenceBasis, value.RecordedAtUnixMillis)
	return err
}

func (r *EpistemicsRepository) RecentExperienceRecords(ctx context.Context, limit int) ([]epistemics.ExperienceRecord, error) {
	if limit < 1 || limit > 100 {
		return nil, fmt.Errorf("invalid experience limit")
	}
	rows, err := r.pool.Query(ctx, `SELECT
		experience_id,source_kind,original_intent_id,source_utterance_id,context_refs,help_method,help_method_ref,
		capability_implementation_ref,capability_usage_observation_ref,capability_gap_ref,skill_ref,expectation_id,
		expected_outcome,actual_outcome,outcome_ref,outcome_detail,human_response_ref,correction_utterance_id,
		verification_evidence,confidence_millis,recorded_at_unix_millis
		FROM epistemics.experience_records ORDER BY recorded_at_unix_millis DESC, experience_id DESC LIMIT $1`, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var result []epistemics.ExperienceRecord
	for rows.Next() {
		var value epistemics.ExperienceRecord
		if err := rows.Scan(&value.ID, &value.SourceKind, &value.OriginalIntentID, &value.SourceUtteranceID, &value.ContextRefs, &value.HelpMethod, &value.HelpMethodRef,
			&value.CapabilityImplementationRef, &value.CapabilityUsageObservationRef, &value.CapabilityGapRef, &value.SkillRef, &value.ExpectationID,
			&value.ExpectedOutcome, &value.ActualOutcome, &value.OutcomeRef, &value.OutcomeDetail, &value.HumanResponseRef, &value.CorrectionUtteranceID,
			&value.VerificationEvidence, &value.ConfidenceMillis, &value.RecordedAtUnixMillis); err != nil {
			return nil, err
		}
		result = append(result, value)
	}
	return result, rows.Err()
}

func (r *EpistemicsRepository) RecentReflectionCandidates(ctx context.Context, limit int) ([]epistemics.ReflectionCandidate, error) {
	if limit < 1 || limit > 100 {
		return nil, fmt.Errorf("invalid reflection limit")
	}
	rows, err := r.pool.Query(ctx, `SELECT
		reflection_candidate_id,trigger,state,source_experience_id,original_intent_id,source_utterance_id,
		 summary,evidence_refs,requires_cognition,recorded_at_unix_millis,revision,claimed_by,claim_expires_at_unix_millis
		FROM epistemics.reflection_candidates ORDER BY recorded_at_unix_millis DESC, reflection_candidate_id DESC LIMIT $1`, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var result []epistemics.ReflectionCandidate
	for rows.Next() {
		var value epistemics.ReflectionCandidate
		if err := rows.Scan(&value.ID, &value.Trigger, &value.State, &value.SourceExperienceID, &value.OriginalIntentID, &value.SourceUtteranceID,
			&value.Summary, &value.EvidenceRefs, &value.RequiresCognition, &value.RecordedAtUnixMillis, &value.Revision, &value.ClaimedBy, &value.ClaimExpiresAtUnixMillis); err != nil {
			return nil, err
		}
		result = append(result, value)
	}
	return result, rows.Err()
}

func (r *EpistemicsRepository) ClaimReflectionCandidate(ctx context.Context, workerID string, nowUnixMillis, leaseMillis int64) (epistemics.ReflectionCandidate, error) {
	if workerID == "" || leaseMillis < 1 {
		return epistemics.ReflectionCandidate{}, fmt.Errorf("invalid reflection claim")
	}
	tx, err := r.pool.Begin(ctx)
	if err != nil {
		return epistemics.ReflectionCandidate{}, err
	}
	defer tx.Rollback(ctx)
	var value epistemics.ReflectionCandidate
	err = tx.QueryRow(ctx, `SELECT reflection_candidate_id,trigger,state,source_experience_id,original_intent_id,source_utterance_id,summary,evidence_refs,requires_cognition,recorded_at_unix_millis,revision,claimed_by,claim_expires_at_unix_millis
		FROM epistemics.reflection_candidates
		WHERE state='OPEN' AND (claim_expires_at_unix_millis=0 OR claim_expires_at_unix_millis < $1)
		ORDER BY recorded_at_unix_millis,reflection_candidate_id
		FOR UPDATE SKIP LOCKED LIMIT 1`, nowUnixMillis).Scan(&value.ID, &value.Trigger, &value.State, &value.SourceExperienceID, &value.OriginalIntentID, &value.SourceUtteranceID, &value.Summary, &value.EvidenceRefs, &value.RequiresCognition, &value.RecordedAtUnixMillis, &value.Revision, &value.ClaimedBy, &value.ClaimExpiresAtUnixMillis)
	if err != nil {
		return epistemics.ReflectionCandidate{}, err
	}
	value.State = epistemics.ReflectionCandidateEvaluating
	value.ClaimedBy = workerID
	value.ClaimExpiresAtUnixMillis = nowUnixMillis + leaseMillis
	_, err = tx.Exec(ctx, `UPDATE epistemics.reflection_candidates SET state=$1,claimed_by=$2,claim_expires_at_unix_millis=$3 WHERE reflection_candidate_id=$4 AND state='OPEN'`, value.State, value.ClaimedBy, value.ClaimExpiresAtUnixMillis, value.ID)
	if err != nil {
		return epistemics.ReflectionCandidate{}, err
	}
	if err := tx.Commit(ctx); err != nil {
		return epistemics.ReflectionCandidate{}, err
	}
	return value, nil
}

func (r *EpistemicsRepository) RecoverReflectionClaims(ctx context.Context, nowUnixMillis int64) (int64, error) {
	result, err := r.pool.Exec(ctx, `UPDATE epistemics.reflection_candidates SET state='OPEN',claimed_by='',claim_expires_at_unix_millis=0 WHERE state='EVALUATING' AND claim_expires_at_unix_millis > 0 AND claim_expires_at_unix_millis < $1`, nowUnixMillis)
	return result.RowsAffected(), err
}

func (r *EpistemicsRepository) ResolveReflectionCandidate(ctx context.Context, id epistemics.ReflectionCandidateID, workerID string, nowUnixMillis int64) error {
	if id == "" || workerID == "" {
		return fmt.Errorf("invalid reflection resolution")
	}
	result, err := r.pool.Exec(ctx, `UPDATE epistemics.reflection_candidates SET state='RESOLVED',claimed_by='',claim_expires_at_unix_millis=0,revision=revision+1 WHERE reflection_candidate_id=$1 AND state='EVALUATING' AND claimed_by=$2 AND claim_expires_at_unix_millis >= $3`, id, workerID, nowUnixMillis)
	if err == nil && result.RowsAffected() != 1 {
		return fmt.Errorf("reflection candidate claim lost")
	}
	return err
}

func (r *EpistemicsRepository) WaitForReflectionCandidate(ctx context.Context, interval time.Duration) error {
	if interval <= 0 {
		return fmt.Errorf("invalid reflection poll interval")
	}
	_, err := r.pool.Exec(ctx, `SELECT pg_sleep($1)`, interval.Seconds())
	return err
}

func (r *EpistemicsRepository) SaveExperienceRecord(ctx context.Context, value epistemics.ExperienceRecord) error {
	_, err := r.pool.Exec(ctx, `INSERT INTO epistemics.experience_records (
		experience_id, source_kind, original_intent_id, source_utterance_id, context_refs, help_method, help_method_ref,
		capability_implementation_ref, capability_usage_observation_ref, capability_gap_ref, skill_ref, expectation_id,
		expected_outcome, actual_outcome, outcome_ref, outcome_detail, human_response_ref, correction_utterance_id,
		verification_evidence, confidence_millis, recorded_at_unix_millis)
		VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11,$12,$13,$14,$15,$16,$17,$18,$19,$20,$21) ON CONFLICT DO NOTHING`,
		value.ID, value.SourceKind, value.OriginalIntentID, value.SourceUtteranceID, value.ContextRefs, value.HelpMethod, value.HelpMethodRef,
		value.CapabilityImplementationRef, value.CapabilityUsageObservationRef, value.CapabilityGapRef, value.SkillRef, value.ExpectationID,
		value.ExpectedOutcome, value.ActualOutcome, value.OutcomeRef, value.OutcomeDetail, value.HumanResponseRef, value.CorrectionUtteranceID,
		value.VerificationEvidence, value.ConfidenceMillis, value.RecordedAtUnixMillis)
	return err
}

func (r *EpistemicsRepository) SaveReflectionCandidate(ctx context.Context, value epistemics.ReflectionCandidate) error {
	_, err := r.pool.Exec(ctx, `INSERT INTO epistemics.reflection_candidates (
		reflection_candidate_id, trigger, state, source_experience_id, original_intent_id, source_utterance_id,
		summary, evidence_refs, requires_cognition, recorded_at_unix_millis, revision)
		VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9,$10,$11) ON CONFLICT DO NOTHING`,
		value.ID, value.Trigger, value.State, value.SourceExperienceID, value.OriginalIntentID, value.SourceUtteranceID,
		value.Summary, value.EvidenceRefs, value.RequiresCognition, value.RecordedAtUnixMillis, value.Revision)
	return err
}