package controllers

import (
	"context"
	"errors"

	"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/cabana"
	"git.golem15.com/golem15/summercms/modules/pact"
	"gorm.io/gorm"
)

// NotFoundControllerID is the 404 log (UI-SPEC C9).
const NotFoundControllerID = "golem15.seo.notfound"

// errNotFoundReadOnly refuses creating or editing 404 log entries: they
// come from the report endpoint only.
var errNotFoundReadOnly = errors.New("golem15.seo: the 404 log is read-only")

// The 404 log's record and bulk action names.
const (
	NotFoundActionRedirect = "redirect"
	NotFoundActionGone     = "gone"
)

// notFoundAdminController lists the 404 log by hits and previews an entry
// with two record actions, a prompted "Create redirect…" (301) and "Mark
// as gone" (410), and the bulk "Mark as gone" (D-20). An entry a redirect
// or a 410 now answers is Resolved: badged, and its actions no longer
// apply.
type notFoundAdminController struct {
	app func() *backpack.App
}

func (notFoundAdminController) ID() string        { return NotFoundControllerID }
func (notFoundAdminController) ModelName() string { return `Golem15\SEO\Models\NotFound` }
func (notFoundAdminController) ConfigDir() string { return "controllers/notfound" }
func (notFoundAdminController) NewRecord() any    { return &models.NotFound{} }
func (notFoundAdminController) RequiredPermissions() []string {
	return []string{PermissionManage}
}

// FormBeforeCreate refuses: entries come from the report endpoint.
func (notFoundAdminController) FormBeforeCreate(context.Context, any) error {
	return errNotFoundReadOnly
}

// FormBeforeUpdate refuses: entries are never edited.
func (notFoundAdminController) FormBeforeUpdate(context.Context, any) error {
	return errNotFoundReadOnly
}

func (c notFoundAdminController) service() *classes.Service {
	svc, err := classes.NewService(appOf(c.app))
	if err != nil {
		return nil
	}
	return svc
}

// cover returns the rule that answers the entry now, nil while it is
// open.
func (c notFoundAdminController) cover(ctx context.Context, entry *models.NotFound) (*models.Redirect, error) {
	db, err := database(ctx, c.app)
	if err != nil {
		return nil, err
	}
	set, err := classes.LoadRedirectSet(db)
	if err != nil {
		return nil, err
	}
	return classes.NotFoundCover(set, entry.URL)
}

// open reports whether a record is an entry no rule answers yet.
func (c notFoundAdminController) open(ctx context.Context, record any) (bool, error) {
	entry, ok := record.(*models.NotFound)
	if !ok || entry == nil {
		return false, nil
	}
	rule, err := c.cover(ctx, entry)
	return rule == nil, err
}

// AdminRecordActions are the preview's two actions (UI-SPEC C9); both
// apply only while the entry is open.
func (c notFoundAdminController) AdminRecordActions() []pact.AdminRecordAction {
	return []pact.AdminRecordAction{
		{
			Name:        NotFoundActionRedirect,
			Label:       "golem15.seo::lang.notfound.redirect",
			Confirm:     "golem15.seo::lang.notfound.redirect_confirm",
			Permissions: []string{PermissionManage},
			Prompt: &pact.AdminActionPrompt{
				Label:       "golem15.seo::lang.notfound.redirect_prompt",
				Placeholder: "golem15.seo::lang.notfound.redirect_placeholder",
				Comment:     "golem15.seo::lang.notfound.redirect_comment",
				MaxLength:   models.MaxRedirectURL,
			},
			Applies: c.open,
			Run: func(ctx context.Context, in pact.AdminRecordActionInput) (pact.AdminRecordActionResult, error) {
				return c.resolve(ctx, in.Record, in.Value)
			},
		},
		{
			Name:        NotFoundActionGone,
			Label:       "golem15.seo::lang.notfound.gone",
			Confirm:     "golem15.seo::lang.notfound.gone_confirm",
			Permissions: []string{PermissionManage},
			Danger:      true,
			Applies:     c.open,
			Run: func(ctx context.Context, in pact.AdminRecordActionInput) (pact.AdminRecordActionResult, error) {
				return c.resolve(ctx, in.Record, "")
			},
		},
	}
}

// resolve creates the entry's 301 to target, or its 410 when target is
// empty, inside the action's transaction.
func (c notFoundAdminController) resolve(ctx context.Context, record any, target string) (pact.AdminRecordActionResult, error) {
	entry, ok := record.(*models.NotFound)
	svc := c.service()
	if !ok || entry == nil || svc == nil {
		return pact.AdminRecordActionResult{}, classes.ErrNotBooted
	}
	db, err := database(ctx, c.app)
	if err != nil {
		return pact.AdminRecordActionResult{}, err
	}
	rule, err := svc.ResolveNotFound(ctx, db, *entry, target)
	if err != nil {
		return pact.AdminRecordActionResult{}, c.refusal(ctx, svc, err)
	}
	tr := translator(c.app)
	if rule.Status == models.Status410 {
		return pact.AdminRecordActionResult{Message: Phrase(ctx, tr, "golem15.seo::lang.notfound.gone_done", map[string]string{"url": entry.URL})}, nil
	}
	return pact.AdminRecordActionResult{Message: Phrase(ctx, tr, "golem15.seo::lang.notfound.redirected", map[string]string{"url": entry.URL, "target": rule.Target})}, nil
}

// refusal turns a 404 action refusal into the admin's answer: a rule that
// already covers the address and a loop are a 403 whose message the admin
// shows as a toast; a bad target is a 422 on the prompt's payload.
func (c notFoundAdminController) refusal(ctx context.Context, svc *classes.Service, err error) error {
	tr := translator(c.app)
	var covered *classes.NotFoundHasRuleError
	var loop *classes.LoopError
	var problems *classes.ProblemsError
	switch {
	case errors.As(err, &covered):
		return &cabana.ForbiddenError{Message: Phrase(ctx, tr, "golem15.seo::lang.notfound.has_rule", map[string]string{"url": covered.URL})}
	case errors.As(err, &loop):
		return &cabana.ForbiddenError{Message: svc.LoopMessage(ctx, loop.Check)}
	case errors.As(err, &problems):
		var msgs []string
		for _, list := range problems.Problems {
			for _, p := range list {
				msgs = append(msgs, Phrase(ctx, tr, p.Key, p.Params))
			}
		}
		return &cabana.ValidationError{Details: map[string]any{"payload": msgs}}
	}
	return err
}

// AdminBulkActions is the list's bulk "Mark as gone" (UI-SPEC C9): one
// entry a rule already answers refuses the whole selection.
func (c notFoundAdminController) AdminBulkActions() []pact.AdminBulkAction {
	return []pact.AdminBulkAction{{
		Name:        NotFoundActionGone,
		Label:       "golem15.seo::lang.notfound.gone",
		Confirm:     "golem15.seo::lang.notfound.gone_selected_confirm",
		Permissions: []string{PermissionManage},
		Run: func(ctx context.Context, in pact.AdminBulkActionInput) (pact.AdminBulkActionResult, error) {
			svc := c.service()
			if svc == nil {
				return pact.AdminBulkActionResult{}, classes.ErrNotBooted
			}
			db, err := database(ctx, c.app)
			if err != nil {
				return pact.AdminBulkActionResult{}, err
			}
			n := 0
			for _, record := range in.Records {
				entry, ok := record.(*models.NotFound)
				if !ok || entry == nil {
					continue
				}
				if _, err := svc.ResolveNotFound(ctx, db, *entry, ""); err != nil {
					return pact.AdminBulkActionResult{}, c.refusal(ctx, svc, err)
				}
				n++
			}
			return pact.AdminBulkActionResult{Message: "golem15.seo::lang.notfound.gone_selected_done", Affected: n}, nil
		},
	}}
}

// ListRowStates marks resolved entries disabled, labelled
// notfound.state_resolved (UI-SPEC C9).
func (notFoundAdminController) ListRowStates(ctx context.Context, db *gorm.DB, records []any) ([][]pact.RowState, error) {
	set, err := classes.LoadRedirectSet(db.WithContext(ctx))
	if err != nil {
		return nil, err
	}
	out := make([][]pact.RowState, len(records))
	for i, record := range records {
		entry, ok := record.(*models.NotFound)
		if !ok || entry == nil {
			continue
		}
		rule, err := classes.NotFoundCover(set, entry.URL)
		if err != nil {
			return nil, err
		}
		if rule != nil {
			out[i] = []pact.RowState{pact.RowStateDisabled}
		}
	}
	return out, nil
}

// HintView is the preview's header partial: the resolved hint, empty
// while the entry is open.
type HintView struct {
	Text string
}

// PartialData serves the preview's hint (notfound.resolved_hint).
func (c notFoundAdminController) PartialData(ctx context.Context, name string, record any) (any, error) {
	entry, ok := record.(*models.NotFound)
	if name != "hint" || !ok || entry == nil {
		return HintView{}, nil
	}
	rule, err := c.cover(ctx, entry)
	if err != nil || rule == nil {
		return HintView{}, err
	}
	label := rule.Source
	if rule.Target != "" {
		label += " → " + rule.Target
	} else {
		label += " → 410"
	}
	return HintView{Text: Phrase(ctx, translator(c.app), "golem15.seo::lang.notfound.resolved_hint", map[string]string{"rule": label})}, nil
}

// FilterOptions serves the status filter's open and resolved choices.
func (notFoundAdminController) FilterOptions(scope string) []pact.Option {
	if scope != models.FilterNotFoundStatus {
		return nil
	}
	return []pact.Option{
		{Value: models.NotFoundOpen, Label: "golem15.seo::lang.notfound.filter_status_open"},
		{Value: models.NotFoundResolved, Label: "golem15.seo::lang.notfound.filter_status_resolved"},
	}
}

var (
	_ pact.AdminController       = notFoundAdminController{}
	_ pact.AdminPermissioned     = notFoundAdminController{}
	_ pact.AdminRecordSource     = notFoundAdminController{}
	_ pact.FormBeforeCreate      = notFoundAdminController{}
	_ pact.FormBeforeUpdate      = notFoundAdminController{}
	_ pact.HasAdminRecordActions = notFoundAdminController{}
	_ pact.HasAdminBulkActions   = notFoundAdminController{}
	_ pact.ListRowStates         = notFoundAdminController{}
	_ pact.AdminPartialData      = notFoundAdminController{}
	_ pact.FilterOptions         = notFoundAdminController{}
)