package controllers

import (
	"context"
	"strconv"

	"git.golem15.com/golem15/sm-seo-plugin/classes"
	"git.golem15.com/golem15/sm-seo-plugin/models"
	"git.golem15.com/golem15/summercms/modules/backpack"
	"git.golem15.com/golem15/summercms/modules/pact"
	"gorm.io/gorm"
)

// RedirectsControllerID is the redirects screen (UI-SPEC C8).
const RedirectsControllerID = "golem15.seo.redirects"

// redirectsAdminController lists and edits redirects (D-16 to D-19). The
// loop refusal, the chain notice and history come from the plugin's own
// field-less form extension on this controller, which runs inside the
// save transaction once the row is written.
type redirectsAdminController struct {
	app func() *backpack.App
}

func (redirectsAdminController) ID() string        { return RedirectsControllerID }
func (redirectsAdminController) ModelName() string { return `Golem15\SEO\Models\Redirect` }
func (redirectsAdminController) ConfigDir() string { return "controllers/redirects" }
func (redirectsAdminController) RequiredPermissions() []string {
	return []string{PermissionManage}
}

// NewRecord is a redirect with the form's defaults, so a save that omits
// an option keeps its default.
func (redirectsAdminController) NewRecord() any {
	r := models.NewRedirect()
	return &r
}

// FormBeforeCreate normalises the redirect and refuses an invalid source,
// target or regex, and a source and match another redirect has.
func (c redirectsAdminController) FormBeforeCreate(ctx context.Context, model any) error {
	return c.check(ctx, model)
}

// FormBeforeUpdate checks an update like a create.
func (c redirectsAdminController) FormBeforeUpdate(ctx context.Context, model any) error {
	return c.check(ctx, model)
}

func (c redirectsAdminController) check(ctx context.Context, model any) error {
	r, ok := model.(*models.Redirect)
	if !ok || r == nil {
		return nil
	}
	r.Normalize()
	db, err := database(ctx, c.app)
	if err != nil {
		return err
	}
	return problemsError(ctx, translator(c.app), r.Problems(db))
}

// FormAfterDelete records the deleted redirect in history inside the
// delete's transaction.
func (c redirectsAdminController) FormAfterDelete(ctx context.Context, model any) error {
	r, ok := model.(*models.Redirect)
	if !ok || r == nil {
		return nil
	}
	svc, err := classes.NewService(appOf(c.app))
	if err != nil {
		return err
	}
	db, err := database(ctx, c.app)
	if err != nil {
		return err
	}
	return svc.Record(ctx, db, classes.Change{
		Kind:      models.SubjectRedirect,
		SubjectID: strconv.FormatUint(uint64(r.ID), 10),
		What:      svc.Phrase("golem15.seo::lang.history.what_redirect", map[string]string{"url": r.Source}),
		Before:    classes.RedirectValues(*r),
	})
}

// ListRowStates marks a chain (UI-SPEC C8): a redirect whose target is
// another redirect's source, labelled redirects.state_chain.
func (redirectsAdminController) ListRowStates(ctx context.Context, db *gorm.DB, records []any) ([][]pact.RowState, error) {
	var targets []string
	for _, record := range records {
		if r, ok := record.(*models.Redirect); ok && r != nil && r.Target != "" {
			targets = append(targets, r.Target)
		}
	}
	sources := map[string]bool{}
	if len(targets) > 0 {
		var rows []string
		if err := db.WithContext(ctx).Model(&models.Redirect{}).Where("source IN ?", targets).Pluck("source", &rows).Error; err != nil {
			return nil, err
		}
		for _, s := range rows {
			sources[s] = true
		}
	}
	out := make([][]pact.RowState, len(records))
	for i, record := range records {
		if r, ok := record.(*models.Redirect); ok && r != nil && r.Target != "" && sources[r.Target] {
			out[i] = []pact.RowState{pact.RowStateNegative}
		}
	}
	return out, nil
}

// matchLabels and originLabels are the phrase keys of the match kinds and
// origins.
var (
	matchLabels = map[string]string{
		models.RedirectExact:   "golem15.seo::lang.redirects.match_exact",
		models.RedirectPattern: "golem15.seo::lang.redirects.match_pattern",
		models.RedirectRegex:   "golem15.seo::lang.redirects.match_regex",
	}
	originLabels = map[string]string{
		models.OriginManual:   "golem15.seo::lang.redirects.origin_manual",
		models.OriginSlug:     "golem15.seo::lang.redirects.origin_slug",
		models.OriginImport:   "golem15.seo::lang.redirects.origin_import",
		models.OriginMCP:      "golem15.seo::lang.redirects.origin_mcp",
		models.OriginNotFound: "golem15.seo::lang.redirects.origin_notfound",
	}
)

// FilterOptions serves the choices of the status, match, origin and chain
// filters.
func (redirectsAdminController) FilterOptions(scope string) []pact.Option {
	switch scope {
	case models.FilterRedirectStatus:
		return []pact.Option{
			{Value: "301", Label: "golem15.seo::lang.redirects.status_301"},
			{Value: "302", Label: "golem15.seo::lang.redirects.status_302"},
			{Value: "410", Label: "golem15.seo::lang.redirects.status_410"},
		}
	case models.FilterRedirectMatch:
		out := make([]pact.Option, 0, len(matchLabels))
		for _, m := range []string{models.RedirectExact, models.RedirectPattern, models.RedirectRegex} {
			out = append(out, pact.Option{Value: m, Label: matchLabels[m]})
		}
		return out
	case models.FilterRedirectOrigin:
		out := make([]pact.Option, 0, len(models.RedirectOrigins))
		for _, o := range models.RedirectOrigins {
			out = append(out, pact.Option{Value: o, Label: originLabels[o]})
		}
		return out
	case models.FilterRedirectChain:
		return []pact.Option{
			{Value: models.ChainOnly, Label: "golem15.seo::lang.redirects.filter_chain_only"},
			{Value: models.ChainHide, Label: "golem15.seo::lang.redirects.filter_chain_hide"},
		}
	}
	return nil
}

// ListExtendRecords shows the match and the origin of the list's rows as
// their labels in the request locale. The rows are list values only and
// never saved; the columns still sort by the stored values.
func (c redirectsAdminController) ListExtendRecords(ctx context.Context, _ *gorm.DB, records []any) error {
	tr := translator(c.app)
	for _, record := range records {
		r, ok := record.(*models.Redirect)
		if !ok || r == nil {
			continue
		}
		if key, ok := matchLabels[r.Match]; ok {
			r.Match = Phrase(ctx, tr, key, nil)
		}
		if key, ok := originLabels[r.Origin]; ok {
			r.Origin = Phrase(ctx, tr, key, nil)
		}
	}
	return nil
}

var (
	_ pact.AdminController   = redirectsAdminController{}
	_ pact.AdminPermissioned = redirectsAdminController{}
	_ pact.AdminRecordSource = redirectsAdminController{}
	_ pact.FormBeforeCreate  = redirectsAdminController{}
	_ pact.FormBeforeUpdate  = redirectsAdminController{}
	_ pact.FormAfterDelete   = redirectsAdminController{}
	_ pact.ListRowStates     = redirectsAdminController{}
	_ pact.FilterOptions     = redirectsAdminController{}
	_ pact.ListExtendRecords = redirectsAdminController{}
)