package repository

import (
	"context"
	"encoding/json"
	"errors"
	"time"

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

	"github.com/yuxingu/digital-psychology/apps/api/internal/model"
)

// ReportRepo persists growth reports and access checks.
type ReportRepo struct {
	Pool *pgxpool.Pool
}

// Create inserts a growth report (optional peer for pair reports).
func (r *ReportRepo) Create(ctx context.Context, userID, profileID uuid.UUID, typ string, summary, detail json.RawMessage) (*model.GrowthReport, error) {
	return r.CreateWithPeer(ctx, userID, profileID, nil, typ, summary, detail)
}

// CreateWithPeer inserts a report with optional peer_profile_id.
func (r *ReportRepo) CreateWithPeer(ctx context.Context, userID, profileID uuid.UUID, peer *uuid.UUID, typ string, summary, detail json.RawMessage) (*model.GrowthReport, error) {
	rep := &model.GrowthReport{}
	err := r.Pool.QueryRow(ctx, `
		INSERT INTO growth_reports(user_id, profile_id, peer_profile_id, type, summary, detail)
		VALUES ($1,$2,$3,$4,$5,$6)
		RETURNING id, user_id, profile_id, type, summary, detail, created_at`,
		userID, profileID, peer, typ, summary, detail,
	).Scan(&rep.ID, &rep.UserID, &rep.ProfileID, &rep.Type, &rep.Summary, &rep.Detail, &rep.CreatedAt)
	if err != nil {
		return nil, err
	}
	rep.PeerProfileID = peer
	return rep, nil
}

// SoftDeleteMatching soft-deletes prior reports for overwrite semantics.
func (r *ReportRepo) SoftDeleteMatching(ctx context.Context, userID, profileID uuid.UUID, peer *uuid.UUID, typ string) error {
	if peer == nil {
		_, err := r.Pool.Exec(ctx, `
			UPDATE growth_reports SET deleted_at=now(), updated_at=now()
			WHERE user_id=$1 AND profile_id=$2 AND type=$3
			  AND peer_profile_id IS NULL AND deleted_at IS NULL`,
			userID, profileID, typ)
		return err
	}
	_, err := r.Pool.Exec(ctx, `
		UPDATE growth_reports SET deleted_at=now(), updated_at=now()
		WHERE user_id=$1 AND type=$2 AND deleted_at IS NULL
		  AND (
		    (profile_id=$3 AND peer_profile_id=$4) OR
		    (profile_id=$4 AND peer_profile_id=$3)
		  )`,
		userID, typ, profileID, *peer)
	return err
}

// UpsertWithPeer soft-deletes matching then inserts.
func (r *ReportRepo) UpsertWithPeer(ctx context.Context, userID, profileID uuid.UUID, peer *uuid.UUID, typ string, summary, detail json.RawMessage) (*model.GrowthReport, error) {
	if err := r.SoftDeleteMatching(ctx, userID, profileID, peer, typ); err != nil {
		return nil, err
	}
	return r.CreateWithPeer(ctx, userID, profileID, peer, typ, summary, detail)
}

// GetLatest returns newest non-deleted report for profile+type(+peer).
func (r *ReportRepo) GetLatest(ctx context.Context, userID, profileID uuid.UUID, typ string, peer *uuid.UUID) (*model.GrowthReport, error) {
	rep := &model.GrowthReport{}
	var peerOut *uuid.UUID
	var err error
	if peer == nil {
		err = r.Pool.QueryRow(ctx, `
			SELECT id, user_id, profile_id, peer_profile_id, type, summary, detail, created_at
			FROM growth_reports
			WHERE user_id=$1 AND profile_id=$2 AND type=$3
			  AND peer_profile_id IS NULL AND deleted_at IS NULL
			ORDER BY created_at DESC LIMIT 1`,
			userID, profileID, typ,
		).Scan(&rep.ID, &rep.UserID, &rep.ProfileID, &peerOut, &rep.Type, &rep.Summary, &rep.Detail, &rep.CreatedAt)
	} else {
		err = r.Pool.QueryRow(ctx, `
			SELECT id, user_id, profile_id, peer_profile_id, type, summary, detail, created_at
			FROM growth_reports
			WHERE user_id=$1 AND type=$2 AND deleted_at IS NULL
			  AND (
			    (profile_id=$3 AND peer_profile_id=$4) OR
			    (profile_id=$4 AND peer_profile_id=$3)
			  )
			ORDER BY created_at DESC LIMIT 1`,
			userID, typ, profileID, *peer,
		).Scan(&rep.ID, &rep.UserID, &rep.ProfileID, &peerOut, &rep.Type, &rep.Summary, &rep.Detail, &rep.CreatedAt)
	}
	if err != nil {
		return nil, err
	}
	rep.PeerProfileID = peerOut
	return rep, nil
}

// SoftDeleteForProfile marks all reports involving a profile as deleted.
func (r *ReportRepo) SoftDeleteForProfile(ctx context.Context, userID, profileID uuid.UUID) error {
	_, err := r.Pool.Exec(ctx, `
		UPDATE growth_reports SET deleted_at=now(), updated_at=now()
		WHERE user_id=$1 AND deleted_at IS NULL
		  AND (profile_id=$2 OR peer_profile_id=$2)`,
		userID, profileID)
	return err
}

// GetForUser loads a report owned by user.
func (r *ReportRepo) GetForUser(ctx context.Context, userID, reportID uuid.UUID) (*model.GrowthReport, error) {
	rep := &model.GrowthReport{}
	err := r.Pool.QueryRow(ctx, `
		SELECT id, user_id, profile_id, type, summary, detail, created_at
		FROM growth_reports WHERE id=$1 AND user_id=$2 AND deleted_at IS NULL`,
		reportID, userID,
	).Scan(&rep.ID, &rep.UserID, &rep.ProfileID, &rep.Type, &rep.Summary, &rep.Detail, &rep.CreatedAt)
	return rep, err
}

// ListForUser returns recent reports for a user (summary only usage at service layer).
func (r *ReportRepo) ListForUser(ctx context.Context, userID uuid.UUID, limit int) ([]model.GrowthReport, error) {
	if limit <= 0 || limit > 100 {
		limit = 50
	}
	rows, err := r.Pool.Query(ctx, `
		SELECT id, user_id, profile_id, type, summary, detail, created_at
		FROM growth_reports
		WHERE user_id=$1 AND deleted_at IS NULL
		ORDER BY created_at DESC
		LIMIT $2`, userID, limit)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	var out []model.GrowthReport
	for rows.Next() {
		var rep model.GrowthReport
		if err := rows.Scan(&rep.ID, &rep.UserID, &rep.ProfileID, &rep.Type, &rep.Summary, &rep.Detail, &rep.CreatedAt); err != nil {
			return nil, err
		}
		out = append(out, rep)
	}
	return out, rows.Err()
}

// HasDeepAccess reports whether user purchased deep access for report.
func (r *ReportRepo) HasDeepAccess(ctx context.Context, userID, reportID uuid.UUID) (bool, error) {
	var ok bool
	err := r.Pool.QueryRow(ctx, `
		SELECT EXISTS(
			SELECT 1 FROM deep_accesses
			WHERE user_id=$1 AND report_id=$2 AND deleted_at IS NULL
		)`, userID, reportID).Scan(&ok)
	return ok, err
}

// HasActiveMembership checks growth membership.
func (r *ReportRepo) HasActiveMembership(ctx context.Context, userID uuid.UUID) (bool, error) {
	var ok bool
	err := r.Pool.QueryRow(ctx, `
		SELECT EXISTS(
			SELECT 1 FROM memberships
			WHERE user_id=$1 AND status='active' AND expires_at > now() AND deleted_at IS NULL
		)`, userID).Scan(&ok)
	return ok, err
}

// MembershipRow is the current membership snapshot for a user.
type MembershipRow struct {
	Plan         string     `json:"plan,omitempty"`
	Status       string     `json:"status"`
	ExpiresAt    *time.Time `json:"expires_at,omitempty"`
	AskQuotaLeft int        `json:"ask_quota_left,omitempty"`
	Active       bool       `json:"active"`
}

// GetMembership returns membership status; missing row → inactive.
func (r *ReportRepo) GetMembership(ctx context.Context, userID uuid.UUID) (*MembershipRow, error) {
	var plan, status string
	var expires *time.Time
	var quota int
	err := r.Pool.QueryRow(ctx, `
		SELECT plan, status, expires_at, ask_quota_left
		FROM memberships
		WHERE user_id=$1 AND deleted_at IS NULL`, userID,
	).Scan(&plan, &status, &expires, &quota)
	if errors.Is(err, pgx.ErrNoRows) {
		return &MembershipRow{Active: false, Status: "none"}, nil
	}
	if err != nil {
		return nil, err
	}
	active := status == "active" && expires != nil && expires.After(time.Now())
	return &MembershipRow{
		Plan: plan, Status: status, ExpiresAt: expires, AskQuotaLeft: quota, Active: active,
	}, nil
}

// CreateOrder inserts an order.
func (r *ReportRepo) CreateOrder(ctx context.Context, userID uuid.UUID, kind, plan string, reportID *uuid.UUID, amount int) (uuid.UUID, error) {
	var id uuid.UUID
	err := r.Pool.QueryRow(ctx, `
		INSERT INTO orders(user_id, kind, plan, report_id, amount_cents, status)
		VALUES ($1,$2,$3,$4,$5,'created') RETURNING id`,
		userID, kind, nullIfEmpty(plan), reportID, amount,
	).Scan(&id)
	return id, err
}

// PayMock marks order paid and grants entitlement.
func (r *ReportRepo) PayMock(ctx context.Context, userID, orderID uuid.UUID) error {
	tx, err := r.Pool.Begin(ctx)
	if err != nil {
		return err
	}
	defer tx.Rollback(ctx)

	var kind string
	var reportID *uuid.UUID
	var plan *string
	err = tx.QueryRow(ctx, `
		SELECT kind, report_id, plan FROM orders
		WHERE id=$1 AND user_id=$2 AND deleted_at IS NULL FOR UPDATE`,
		orderID, userID,
	).Scan(&kind, &reportID, &plan)
	if err != nil {
		return err
	}
	if _, err := tx.Exec(ctx, `UPDATE orders SET status='paid', updated_at=now() WHERE id=$1`, orderID); err != nil {
		return err
	}
	if _, err := tx.Exec(ctx, `
		INSERT INTO payments(order_id, channel, status) VALUES ($1,'mock','paid')`, orderID); err != nil {
		return err
	}
	switch kind {
	case "deep_access":
		if reportID == nil {
			return errMissingReport
		}
		if _, err := tx.Exec(ctx, `
			INSERT INTO deep_accesses(user_id, report_id, order_id)
			VALUES ($1,$2,$3)
			ON CONFLICT (user_id, report_id) DO NOTHING`, userID, *reportID, orderID); err != nil {
			return err
		}
	case "membership":
		p := "month"
		if plan != nil && *plan != "" {
			p = *plan
		}
		days := 31
		if p == "quarter" {
			days = 92
		} else if p == "year" {
			days = 366
		}
		if _, err := tx.Exec(ctx, `
			INSERT INTO memberships(user_id, plan, status, expires_at, ask_quota_left)
			VALUES ($1,$2,'active', now() + ($3 * interval '1 day'), 100)
			ON CONFLICT (user_id) DO UPDATE SET
				plan=EXCLUDED.plan, status='active',
				expires_at=EXCLUDED.expires_at, ask_quota_left=100, updated_at=now()`,
			userID, p, days); err != nil {
			return err
		}
	case "ask_pack":
		p := "pack10"
		if plan != nil && *plan != "" {
			p = *plan
		}
		delta := AskPackQuota(p)
		if delta <= 0 {
			return errString("invalid ask_pack plan")
		}
		if _, err := tx.Exec(ctx, `
			UPDATE users SET ask_paid_quota_left = ask_paid_quota_left + $2, updated_at=now()
			WHERE id=$1 AND deleted_at IS NULL`, userID, delta); err != nil {
			return err
		}
	}
	return tx.Commit(ctx)
}

// AskPackQuota returns how many ask replies a pack plan grants.
func AskPackQuota(plan string) int {
	switch plan {
	case "pack10":
		return 10
	case "pack30":
		return 30
	case "pack100":
		return 100
	default:
		return 0
	}
}

// AskPackAmountCents is mock price for an ask pack plan.
func AskPackAmountCents(plan string) int {
	switch plan {
	case "pack10":
		return 990
	case "pack30":
		return 1980
	case "pack100":
		return 4990
	default:
		return 0
	}
}

var errMissingReport = errString("report_id required for deep_access")

type errString string

func (e errString) Error() string { return string(e) }

func nullIfEmpty(s string) *string {
	if s == "" {
		return nil
	}
	return &s
}