// Package waf implements CRUD for per-domain WAF policies (waf_configs).
package waf

import (
	"context"
	"errors"
	"time"

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

	"git.netcell-it.de/projekte/edgeguard-native/internal/models"
)

var ErrNotFound = errors.New("waf config not found")

type Repo struct {
	Pool *pgxpool.Pool
}

func New(pool *pgxpool.Pool) *Repo { return &Repo{Pool: pool} }

const baseSelect = `
SELECT id, domain_id, enabled, mode, paranoia_level,
       rule_exclusions, exclusion_notes, trusted_proxies, custom_rules, updated_at
FROM waf_configs
`

func scan(row pgx.Row) (*models.WafConfig, error) {
	var c models.WafConfig
	err := row.Scan(
		&c.ID, &c.DomainID, &c.Enabled, &c.Mode, &c.ParanoiaLevel,
		&c.RuleExclusions, &c.ExclusionNotes, &c.TrustedProxies, &c.CustomRules, &c.UpdatedAt,
	)
	if err != nil {
		return nil, err
	}
	if c.ExclusionNotes == nil {
		c.ExclusionNotes = map[string]string{}
	}
	return &c, nil
}

// List returns all WAF configs ordered by domain_id.
func (r *Repo) List(ctx context.Context) ([]models.WafConfig, error) {
	rows, err := r.Pool.Query(ctx, baseSelect+" ORDER BY domain_id ASC")
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	out := make([]models.WafConfig, 0, 16)
	for rows.Next() {
		c, err := scan(rows)
		if err != nil {
			return nil, err
		}
		out = append(out, *c)
	}
	return out, rows.Err()
}

// GetByDomain returns the WAF config for a domain, or ErrNotFound.
func (r *Repo) GetByDomain(ctx context.Context, domainID int64) (*models.WafConfig, error) {
	row := r.Pool.QueryRow(ctx, baseSelect+" WHERE domain_id = $1", domainID)
	c, err := scan(row)
	if err != nil {
		if errors.Is(err, pgx.ErrNoRows) {
			return nil, ErrNotFound
		}
		return nil, err
	}
	return c, nil
}

// Upsert inserts or updates the WAF config for a domain.
// Returns the resulting row.
func (r *Repo) Upsert(ctx context.Context, c models.WafConfig) (*models.WafConfig, error) {
	c.UpdatedAt = time.Now()
	if c.ExclusionNotes == nil {
		c.ExclusionNotes = map[string]string{}
	}
	row := r.Pool.QueryRow(ctx, `
		INSERT INTO waf_configs
		    (domain_id, enabled, mode, paranoia_level,
		     rule_exclusions, exclusion_notes, trusted_proxies, custom_rules, updated_at)
		VALUES ($1,$2,$3,$4,$5,$6,$7,$8,$9)
		ON CONFLICT (domain_id) DO UPDATE SET
		    enabled          = EXCLUDED.enabled,
		    mode             = EXCLUDED.mode,
		    paranoia_level   = EXCLUDED.paranoia_level,
		    rule_exclusions  = EXCLUDED.rule_exclusions,
		    exclusion_notes  = EXCLUDED.exclusion_notes,
		    trusted_proxies  = EXCLUDED.trusted_proxies,
		    custom_rules     = EXCLUDED.custom_rules,
		    updated_at       = EXCLUDED.updated_at
		RETURNING id, domain_id, enabled, mode, paranoia_level,
		          rule_exclusions, exclusion_notes, trusted_proxies, custom_rules, updated_at
	`,
		c.DomainID, c.Enabled, c.Mode, c.ParanoiaLevel,
		c.RuleExclusions, c.ExclusionNotes, c.TrustedProxies, c.CustomRules, c.UpdatedAt,
	)
	return scan(row)
}

// ListEnabled returns only configs with enabled=true (used by the WAF agent).
func (r *Repo) ListEnabled(ctx context.Context) ([]models.WafConfig, error) {
	rows, err := r.Pool.Query(ctx, baseSelect+" WHERE enabled = true ORDER BY domain_id ASC")
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	out := make([]models.WafConfig, 0, 8)
	for rows.Next() {
		c, err := scan(rows)
		if err != nil {
			return nil, err
		}
		out = append(out, *c)
	}
	return out, rows.Err()
}

// WafAlert mirrors the waf_alerts DB row.
type WafAlert struct {
	ID        int64      `json:"id"`
	DomainID  *int64     `json:"domain_id,omitempty"`
	Hostname  string     `json:"hostname"`
	ClientIP  string     `json:"client_ip"`
	Method    string     `json:"method"`
	URI       string     `json:"uri"`
	RuleID    int        `json:"rule_id"`
	RuleMsg   string     `json:"rule_msg"`
	Severity  string     `json:"severity"`
	Action    string     `json:"action"`
	CreatedAt time.Time  `json:"created_at"`
}

// ListAlerts returns recent WAF alerts, optionally filtered by domain_id.
func (r *Repo) ListAlerts(ctx context.Context, domainID *int64, limit int) ([]WafAlert, error) {
	if limit <= 0 || limit > 1000 {
		limit = 200
	}
	var rows interface{ Next() bool; Scan(...any) error; Close(); Err() error }
	var err error
	if domainID != nil {
		rows2, e := r.Pool.Query(ctx, `
			SELECT id, domain_id, hostname, client_ip, method, uri,
			       rule_id, rule_msg, severity, action, created_at
			FROM waf_alerts
			WHERE domain_id = $1
			ORDER BY created_at DESC LIMIT $2
		`, *domainID, limit)
		rows, err = rows2, e
	} else {
		rows2, e := r.Pool.Query(ctx, `
			SELECT id, domain_id, hostname, client_ip, method, uri,
			       rule_id, rule_msg, severity, action, created_at
			FROM waf_alerts
			ORDER BY created_at DESC LIMIT $1
		`, limit)
		rows, err = rows2, e
	}
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	out := make([]WafAlert, 0, limit)
	for rows.Next() {
		var a WafAlert
		if err := rows.Scan(
			&a.ID, &a.DomainID, &a.Hostname, &a.ClientIP, &a.Method, &a.URI,
			&a.RuleID, &a.RuleMsg, &a.Severity, &a.Action, &a.CreatedAt,
		); err != nil {
			return nil, err
		}
		out = append(out, a)
	}
	return out, rows.Err()
}

// PurgeAlerts removes alerts older than the given number of days.
func (r *Repo) PurgeAlerts(ctx context.Context, olderThanDays int) error {
	_, err := r.Pool.Exec(ctx,
		`DELETE FROM waf_alerts WHERE created_at < NOW() - ($1 || ' days')::interval`,
		olderThanDays,
	)
	return err
}

// DomainConfigPair combines a domain hostname with its WAF config.
type DomainConfigPair struct {
	Hostname string
	Config   models.WafConfig
}

// ListAllWithDomain returns all WAF configs joined with their domain name.
// Used by the WAF agent to build the hostname→engine mapping.
func (r *Repo) ListAllWithDomain(ctx context.Context) ([]DomainConfigPair, error) {
	rows, err := r.Pool.Query(ctx, `
		SELECT d.name,
		       w.id, w.domain_id, w.enabled, w.mode, w.paranoia_level,
		       w.rule_exclusions, w.trusted_proxies, w.custom_rules, w.updated_at
		FROM waf_configs w
		JOIN domains d ON d.id = w.domain_id
		WHERE d.active = true
		ORDER BY d.name ASC
	`)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	out := make([]DomainConfigPair, 0, 16)
	for rows.Next() {
		var p DomainConfigPair
		var c models.WafConfig
		if err := rows.Scan(
			&p.Hostname,
			&c.ID, &c.DomainID, &c.Enabled, &c.Mode, &c.ParanoiaLevel,
			&c.RuleExclusions, &c.TrustedProxies, &c.CustomRules, &c.UpdatedAt,
		); err != nil {
			return nil, err
		}
		p.Config = c
		out = append(out, p)
	}
	return out, rows.Err()
}