// Copyright (c) 2025-2026 Probo Inc <hello@probo.com>.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.

package coredata

import (
	"context"
	"errors"
	"fmt"
	"strings"
	"time"

	"github.com/jackc/pgx/v5"
	"github.com/jackc/pgx/v5/pgconn"
	"go.gearno.de/kit/pg"
	"go.probo.inc/probo/pkg/gid"
	"go.probo.inc/probo/pkg/iam/policy"
	"go.probo.inc/probo/pkg/mail"
	"go.probo.inc/probo/pkg/page"
)

type (
	Identity struct {
		ID                   gid.GID   `db:"id"`
		EmailAddress         mail.Addr `db:"email_address"`
		FullName             string    `db:"full_name"`
		HashedPassword       []byte    `db:"hashed_password"`
		EmailAddressVerified bool      `db:"email_address_verified"`
		SAMLSubject          *string   `db:"saml_subject"`
		Locale               *string   `db:"locale"`
		CreatedAt            time.Time `db:"created_at"`
		UpdatedAt            time.Time `db:"updated_at"`
	}

	Identities []*Identity
)

var (
	ErrSAMLSubjectAlreadyExists = errors.New("saml subject already exists")
)

func (i Identity) CursorKey(orderBy IdentityOrderField) page.CursorKey {
	switch orderBy {
	case IdentityOrderFieldCreatedAt:
		return page.NewCursorKey(i.ID, i.CreatedAt)
	}

	panic(fmt.Sprintf("unsupported order by: %s", orderBy))
}

// Tenant id scope is not applied because we want to access identities across all tenants for authentication purposes.
func (i *Identity) LoadByEmail(
	ctx context.Context,
	conn pg.Querier,
	email mail.Addr,
) error {
	q := `
SELECT
    id,
    email_address,
    full_name,
    hashed_password,
    email_address_verified,
    saml_subject,
    locale,
    created_at,
    updated_at
FROM
    identities
WHERE
    email_address = @identity_email
LIMIT 1;
`

	args := pgx.StrictNamedArgs{"identity_email": email}

	rows, err := conn.Query(ctx, q, args)
	if err != nil {
		return fmt.Errorf("cannot query identity: %w", err)
	}

	identity, err := pgx.CollectExactlyOneRow(rows, pgx.RowToStructByName[Identity])
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return ErrResourceNotFound
		}

		return fmt.Errorf("cannot collect identity: %w", err)
	}

	*i = identity

	return nil
}

// Tenant id scope is not applied because we want to access identities across all tenants for authentication purposes.
func (i *Identity) LoadByID(
	ctx context.Context,
	conn pg.Querier,
	identityID gid.GID,
) error {
	q := `
SELECT
    id,
    email_address,
    full_name,
    hashed_password,
    email_address_verified,
    saml_subject,
    locale,
    created_at,
    updated_at
FROM
    identities
WHERE
    id = @identity_id
LIMIT 1;
`

	args := pgx.StrictNamedArgs{"identity_id": identityID}

	rows, err := conn.Query(ctx, q, args)
	if err != nil {
		return fmt.Errorf("cannot query identity: %w", err)
	}

	identity, err := pgx.CollectExactlyOneRow(rows, pgx.RowToStructByName[Identity])
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return ErrResourceNotFound
		}

		return fmt.Errorf("cannot collect identity: %w", err)
	}

	*i = identity

	return nil
}

// AuthorizationAttributes loads the minimal authorization attributes for policy condition evaluation.
// It is intentionally lightweight and does not populate the Identity struct.
func (i *Identity) AuthorizationAttributes(
	ctx context.Context,
	conn pg.Querier,
	resourceIDs []gid.GID,
) (policy.AttributesByID, error) {
	q := `
SELECT
    id,
    email_address
FROM
    identities
WHERE
    id = ANY(@resource_ids::text[])
`

	args := pgx.StrictNamedArgs{
		"resource_ids": resourceIDs,
	}

	rows, err := conn.Query(ctx, q, args)
	if err != nil {
		return nil, fmt.Errorf("cannot query identity authorization attributes: %w", err)
	}
	defer rows.Close()

	attrsByID := make(policy.AttributesByID, len(resourceIDs))

	for rows.Next() {
		var (
			id           gid.GID
			emailAddress string
		)

		if err := rows.Scan(&id, &emailAddress); err != nil {
			return nil, fmt.Errorf("cannot scan identity authorization attributes: %w", err)
		}

		attrsByID[id] = policy.Attributes{
			"identity_id": id.String(),
			"email":       emailAddress,
		}
	}

	if err := rows.Err(); err != nil {
		return nil, fmt.Errorf("cannot iterate identity authorization attributes: %w", err)
	}

	return attrsByID, nil
}

func (i *Identity) Insert(
	ctx context.Context,
	conn pg.Tx,
) error {
	q := `
INSERT INTO
    identities (
        id,
        email_address,
        full_name,
        hashed_password,
        email_address_verified,
        saml_subject,
        locale,
        created_at,
        updated_at
    )
VALUES (
    @identity_id,
    @email_address,
    @full_name,
    @hashed_password,
    @email_address_verified,
    @saml_subject,
    @locale,
    @created_at,
    @updated_at
)
`

	args := pgx.StrictNamedArgs{
		"identity_id":            i.ID,
		"email_address":          i.EmailAddress,
		"full_name":              i.FullName,
		"hashed_password":        i.HashedPassword,
		"saml_subject":           i.SAMLSubject,
		"locale":                 i.Locale,
		"created_at":             i.CreatedAt,
		"updated_at":             i.UpdatedAt,
		"email_address_verified": i.EmailAddressVerified,
	}

	_, err := conn.Exec(ctx, q, args)
	if err != nil {
		if pgErr, ok := errors.AsType[*pgconn.PgError](err); ok && pgErr.Code == "23505" {
			switch pgErr.ConstraintName {
			case "idx_users_saml_subject":
				return ErrSAMLSubjectAlreadyExists
			case "usrmgr_users_email_address_key":
				return ErrResourceAlreadyExists
			}
		}

		return err
	}

	return nil
}

func (i *Identity) Update(ctx context.Context, conn pg.Tx) error {
	q := `
UPDATE
    identities
SET
    email_address = @email_address,
    full_name = @full_name,
    email_address_verified = @email_address_verified,
    saml_subject = @saml_subject,
    hashed_password = @hashed_password,
    locale = @locale,
    updated_at = @updated_at
WHERE
    id = @identity_id
`

	args := pgx.StrictNamedArgs{
		"identity_id":            i.ID,
		"email_address":          i.EmailAddress,
		"full_name":              i.FullName,
		"email_address_verified": i.EmailAddressVerified,
		"saml_subject":           i.SAMLSubject,
		"hashed_password":        i.HashedPassword,
		"locale":                 i.Locale,
		"updated_at":             i.UpdatedAt,
	}

	result, err := conn.Exec(ctx, q, args)
	if err != nil {
		if pgErr, ok := errors.AsType[*pgconn.PgError](err); ok && pgErr.Code == "23505" {
			switch pgErr.ConstraintName {
			case "idx_users_saml_subject":
				return ErrSAMLSubjectAlreadyExists
			case "usrmgr_users_email_address_key":
				return ErrResourceAlreadyExists
			}
		}

		return fmt.Errorf("cannot update identity: %w", err)
	}

	if result.RowsAffected() == 0 {
		return ErrResourceNotFound
	}

	return nil
}

// LoadBySAMLSubject loads an identity by their SAML subject (NameID)
func (i *Identity) LoadBySAMLSubject(
	ctx context.Context,
	conn pg.Querier,
	samlSubject string,
) error {
	if strings.TrimSpace(samlSubject) == "" {
		return ErrResourceNotFound
	}

	q := `
SELECT
    id,
    email_address,
    full_name,
    hashed_password,
    email_address_verified,
    saml_subject,
    locale,
    created_at,
    updated_at
FROM
    identities
WHERE
    saml_subject = @saml_subject
LIMIT 1;
`

	args := pgx.StrictNamedArgs{"saml_subject": samlSubject}

	rows, err := conn.Query(ctx, q, args)
	if err != nil {
		return fmt.Errorf("cannot query identity by SAML subject: %w", err)
	}

	identity, err := pgx.CollectExactlyOneRow(rows, pgx.RowToStructByName[Identity])
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return ErrResourceNotFound
		}

		return fmt.Errorf("cannot collect identity: %w", err)
	}

	*i = identity

	return nil
}

func (i *Identity) CountMemberships(
	ctx context.Context,
	conn pg.Querier,
) (int, error) {
	q := `
SELECT
    COUNT(*)
FROM
    iam_memberships
WHERE
    identity_id = @identity_id
`

	args := pgx.StrictNamedArgs{"identity_id": i.ID}

	var count int

	err := conn.QueryRow(ctx, q, args).Scan(&count)
	if err != nil {
		return 0, fmt.Errorf("cannot count identity memberships: %w", err)
	}

	return count, nil
}

func (i *Identities) LoadByIDs(
	ctx context.Context,
	conn pg.Querier,
	identityIDs []gid.GID,
) error {
	q := `
SELECT
    id,
    email_address,
    full_name,
    hashed_password,
    email_address_verified,
    saml_subject,
    locale,
    created_at,
    updated_at
FROM
    identities
WHERE
    id = ANY(@identity_ids)
`

	args := pgx.StrictNamedArgs{"identity_ids": identityIDs}

	rows, err := conn.Query(ctx, q, args)
	if err != nil {
		return fmt.Errorf("cannot query identities: %w", err)
	}

	identities, err := pgx.CollectRows(rows, pgx.RowToAddrOfStructByName[Identity])
	if err != nil {
		return fmt.Errorf("cannot collect identities: %w", err)
	}

	*i = identities

	return nil
}