package controllers

import (
	"context"
	"errors"
	"fmt"
	"net/url"
	"sort"
	"strconv"
	"time"

	"git.golem15.com/golem15/sm-seo-plugin/classes"
	"git.golem15.com/golem15/sm-seo-plugin/classes/crawl"
	"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"
)

// CrawlsControllerID is the Crawls screen (UI-SPEC C24).
const CrawlsControllerID = "golem15.seo.crawls"

// CrawlActionCancel is the preview's Cancel crawl.
const CrawlActionCancel = "cancel"

// errCrawlReadOnly refuses creating or editing crawls.
var errCrawlReadOnly = errors.New("golem15.seo: crawls are read-only")

// crawlsAdminController lists the crawls, newest first, and previews one
// with P6 and Cancel while it is queued or running; the toolbar starts a
// crawl and deletes the selected ones (a running crawl refuses).
type crawlsAdminController struct {
	app func() *backpack.App
}

func (crawlsAdminController) ID() string        { return CrawlsControllerID }
func (crawlsAdminController) ModelName() string { return `Golem15\SEO\Models\Crawl` }
func (crawlsAdminController) ConfigDir() string { return "controllers/crawls" }
func (crawlsAdminController) NewRecord() any    { return &models.Crawl{} }
func (crawlsAdminController) RequiredPermissions() []string {
	return []string{PermissionManage}
}

// FormBeforeCreate refuses: crawls are started with Start crawl.
func (crawlsAdminController) FormBeforeCreate(context.Context, any) error { return errCrawlReadOnly }

// FormBeforeUpdate refuses: crawls are never edited.
func (crawlsAdminController) FormBeforeUpdate(context.Context, any) error { return errCrawlReadOnly }

// FormBeforeDelete refuses a queued or running crawl with
// crawls.delete_running (403).
func (c crawlsAdminController) FormBeforeDelete(ctx context.Context, model any) error {
	row, ok := model.(*models.Crawl)
	if ok && row != nil && row.Active() {
		return &cabana.ForbiddenError{Message: Phrase(ctx, translator(c.app), "golem15.seo::lang.crawls.delete_running", nil)}
	}
	return nil
}

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

// AdminActions is the toolbar's Start crawl.
func (c crawlsAdminController) AdminActions() []pact.AdminAction {
	return []pact.AdminAction{startCrawl(c.app)}
}

// AdminRecordActions is Cancel crawl while queued or running; the pages
// and issues fetched so far are kept.
func (c crawlsAdminController) AdminRecordActions() []pact.AdminRecordAction {
	return []pact.AdminRecordAction{{
		Name:        CrawlActionCancel,
		Label:       "golem15.seo::lang.crawls.cancel",
		Confirm:     "golem15.seo::lang.crawls.cancel_confirm",
		Permissions: []string{PermissionManage},
		Applies: func(_ context.Context, record any) (bool, error) {
			row, ok := record.(*models.Crawl)
			return ok && row != nil && row.Active(), nil
		},
		Run: func(ctx context.Context, in pact.AdminRecordActionInput) (pact.AdminRecordActionResult, error) {
			row, ok := in.Record.(*models.Crawl)
			svc := c.service()
			if !ok || row == nil || svc == nil {
				return pact.AdminRecordActionResult{}, classes.ErrNotBooted
			}
			db, err := database(ctx, c.app)
			if err != nil {
				return pact.AdminRecordActionResult{}, err
			}
			_, name, _ := svc.Actor(ctx, db)
			if err := crawl.Cancel(ctx, svc, db, *row, name); err != nil {
				return pact.AdminRecordActionResult{}, err
			}
			return pact.AdminRecordActionResult{Message: "golem15.seo::lang.crawls.cancelled"}, nil
		},
	}}
}

// statusKeys are the phrase keys of the crawl states.
var statusKeys = map[string]string{
	models.CrawlQueued:    "golem15.seo::lang.crawls.st_queued",
	models.CrawlRunning:   "golem15.seo::lang.crawls.st_running",
	models.CrawlFinished:  "golem15.seo::lang.crawls.st_finished",
	models.CrawlFailed:    "golem15.seo::lang.crawls.st_failed",
	models.CrawlCancelled: "golem15.seo::lang.crawls.st_cancelled",
}

// TriggerLabel is the Started by cell: Manual: name, Schedule or MCP:
// client.
func TriggerLabel(ctx context.Context, svc *classes.Service, row models.Crawl) string {
	switch row.Trigger {
	case models.TriggerSchedule:
		return svc.PhraseCtx(ctx, "golem15.seo::lang.crawls.by_schedule", nil)
	case models.TriggerMCP:
		return svc.PhraseCtx(ctx, "golem15.seo::lang.crawls.by_mcp", map[string]string{"client": row.TriggerName})
	}
	return svc.PhraseCtx(ctx, "golem15.seo::lang.crawls.by_admin", map[string]string{"name": row.TriggerName})
}

// Duration is a crawl's duration, e.g. "4 min 12 s"; "—" before it ends.
func Duration(row models.Crawl) string {
	if row.StartedAt == nil {
		return "—"
	}
	end := time.Now().UTC()
	if row.FinishedAt != nil {
		end = *row.FinishedAt
	}
	d := end.Sub(*row.StartedAt).Round(time.Second)
	if d < 0 {
		d = 0
	}
	h, m, s := int(d.Hours()), int(d.Minutes())%60, int(d.Seconds())%60
	switch {
	case h > 0:
		return fmt.Sprintf("%d h %d min", h, m)
	case m > 0:
		return fmt.Sprintf("%d min %d s", m, s)
	}
	return fmt.Sprintf("%d s", s)
}

// issueCounts counts the issues of crawls.
func issueCounts(db *gorm.DB, ids []uint) (map[uint]int, error) {
	out := map[uint]int{}
	if len(ids) == 0 {
		return out, nil
	}
	var rows []struct {
		CrawlID uint
		N       int
	}
	if err := db.Raw(`SELECT crawl_id, COUNT(*) AS n FROM golem15_seo_issues WHERE crawl_id IN ? GROUP BY crawl_id`, ids).Scan(&rows).Error; err != nil {
		return nil, err
	}
	for _, r := range rows {
		out[r.CrawlID] = r.N
	}
	return out, nil
}

// ListExtendRecords shows the state, pages (with the limit note), issue
// count, trigger and duration of each crawl in the request locale.
func (c crawlsAdminController) ListExtendRecords(ctx context.Context, db *gorm.DB, records []any) error {
	svc := c.service()
	if svc == nil {
		return nil
	}
	var ids []uint
	for _, r := range records {
		if row, ok := r.(*models.Crawl); ok && row != nil {
			ids = append(ids, row.ID)
		}
	}
	counts, err := issueCounts(db.WithContext(ctx), ids)
	if err != nil {
		return err
	}
	for _, r := range records {
		row, ok := r.(*models.Crawl)
		if !ok || row == nil {
			continue
		}
		row.PagesCell = strconv.Itoa(row.Pages)
		if row.LimitHit {
			row.PagesCell = svc.PhraseCtx(ctx, "golem15.seo::lang.crawls.pages_limit", map[string]string{"count": strconv.Itoa(row.Pages)})
		}
		row.IssuesCell = strconv.Itoa(counts[row.ID])
		row.DurationCell = Duration(*row)
		row.TriggerCell = TriggerLabel(ctx, svc, *row)
		if key, ok := statusKeys[row.Status]; ok {
			row.Status = svc.PhraseCtx(ctx, key, nil)
		}
	}
	return nil
}

// DropdownOptions labels the preview's read-only status and trigger.
func (crawlsAdminController) DropdownOptions(field string) []pact.Option {
	switch field {
	case "status":
		out := make([]pact.Option, 0, len(models.CrawlStatuses))
		for _, s := range models.CrawlStatuses {
			out = append(out, pact.Option{Value: s, Label: statusKeys[s]})
		}
		return out
	case "trigger":
		return []pact.Option{
			{Value: models.TriggerAdmin, Label: "golem15.seo::lang.crawls.trigger_admin"},
			{Value: models.TriggerSchedule, Label: "golem15.seo::lang.crawls.trigger_schedule"},
			{Value: models.TriggerMCP, Label: "golem15.seo::lang.crawls.trigger_mcp"},
		}
	}
	return nil
}

// FilterOptions serves the status filter.
func (c crawlsAdminController) FilterOptions(scope string) []pact.Option {
	if scope != models.FilterCrawlStatus {
		return nil
	}
	return c.DropdownOptions("status")
}

// PartialData serves P6 crawl_summary (UI-SPEC C24).
func (c crawlsAdminController) PartialData(ctx context.Context, name string, record any) (any, error) {
	row, ok := record.(*models.Crawl)
	svc := c.service()
	if name != "crawl_summary" || !ok || row == nil || svc == nil {
		return classes.CrawlSummaryView{}, nil
	}
	db, err := database(ctx, c.app)
	if err != nil {
		return nil, err
	}
	return CrawlSummary(ctx, svc, db, c.app, *row)
}

// CrawlSummary builds P6: one status callout, the staging and rendered
// comparison lines, the stats strip and the per-kind table whose counts
// link to the Site audit list filtered by the kind.
func CrawlSummary(ctx context.Context, svc *classes.Service, db *gorm.DB, app func() *backpack.App, row models.Crawl) (classes.CrawlSummaryView, error) {
	view := classes.CrawlSummaryView{}
	p := func(key string, params map[string]string) string {
		return svc.PhraseCtx(ctx, "golem15.seo::lang.crawls."+key, params)
	}
	stamp := func(t *time.Time) string {
		if t == nil {
			return "—"
		}
		return t.UTC().Format("2006-01-02 15:04 UTC")
	}
	switch row.Status {
	case models.CrawlRunning:
		view.Title = p("running_title", nil)
		view.Text = p("running_text", map[string]string{"done": strconv.Itoa(row.Pages), "limit": strconv.Itoa(row.MaxPages)})
	case models.CrawlQueued:
		view.Text = p("queued_text", nil)
	case models.CrawlFailed:
		view.Tone = "danger"
		view.Title = p("failed_title", nil)
		view.Text = p("failed_text", map[string]string{"error": row.Error})
	case models.CrawlCancelled:
		view.Text = p("cancelled_text", map[string]string{"name": row.CancelledBy, "time": stamp(row.FinishedAt)})
	case models.CrawlFinished:
		if row.LimitHit {
			view.Tone = "warning"
			view.Text = p("limit_text", map[string]string{"limit": strconv.Itoa(row.MaxPages)})
		}
	}
	view.HasCallout = view.Text != ""
	if svc.Staging() {
		view.Staging = p("staging_text", nil)
	}
	switch row.RenderStatus {
	case models.RenderDone:
		view.Render = svc.ChoiceCtx(ctx, "golem15.seo::lang.crawls.render_done", row.RenderPages, nil)
	case models.RenderFailed:
		view.Render = p("render_failed", map[string]string{"error": row.RenderNote})
	default:
		view.Render = p("render_skipped", nil)
	}
	var rows []struct {
		Kind     string
		Severity string
		N        int
	}
	if err := db.Raw(`SELECT kind, severity, COUNT(*) AS n FROM golem15_seo_issues WHERE crawl_id = ? GROUP BY kind, severity`, row.ID).Scan(&rows).Error; err != nil {
		return view, err
	}
	sevCount := map[string]int{}
	prefix, err := cabana.AdminPrefix(appOf(app))
	if err != nil {
		prefix = cabana.DefaultAdminPrefix
	}
	for _, r := range rows {
		sevCount[r.Severity] += r.N
		view.Kinds = append(view.Kinds, classes.CrawlKindRow{
			Kind:     r.Kind,
			Label:    svc.PhraseCtx(ctx, "golem15.seo::lang.issues.kind_"+r.Kind, nil),
			Severity: svc.PhraseCtx(ctx, labelKeys[r.Severity], nil),
			Count:    r.N,
			Link:     prefix + "/golem15/seo/issues?" + url.Values{"filter[kind]": {r.Kind}}.Encode(),
		})
	}
	rank := map[string]int{}
	for _, r := range rows {
		rank[r.Kind] = models.SeverityRank(r.Severity)
	}
	sort.SliceStable(view.Kinds, func(i, j int) bool {
		a, b := view.Kinds[i], view.Kinds[j]
		if rank[a.Kind] != rank[b.Kind] {
			return rank[a.Kind] < rank[b.Kind]
		}
		if a.Count != b.Count {
			return a.Count > b.Count
		}
		return a.Kind < b.Kind
	})
	view.NoIssues = len(view.Kinds) == 0 && !row.Active()
	view.Stats = []classes.CrawlStat{
		{Label: p("stat_pages", nil), Value: strconv.Itoa(row.Pages)},
		{Label: p("stat_errors", nil), Value: strconv.Itoa(sevCount[models.SeverityError])},
		{Label: p("stat_warnings", nil), Value: strconv.Itoa(sevCount[models.SeverityWarning])},
		{Label: p("stat_notices", nil), Value: strconv.Itoa(sevCount[models.SeverityNotice])},
		{Label: p("stat_duration", nil), Value: Duration(row)},
	}
	return view, nil
}

var (
	_ pact.AdminController         = crawlsAdminController{}
	_ pact.AdminPermissioned       = crawlsAdminController{}
	_ pact.AdminRecordSource       = crawlsAdminController{}
	_ pact.FormBeforeCreate        = crawlsAdminController{}
	_ pact.FormBeforeUpdate        = crawlsAdminController{}
	_ pact.FormBeforeDelete        = crawlsAdminController{}
	_ pact.HasAdminActions         = crawlsAdminController{}
	_ pact.HasAdminRecordActions   = crawlsAdminController{}
	_ pact.ListExtendRecords       = crawlsAdminController{}
	_ pact.DropdownOptionsProvider = crawlsAdminController{}
	_ pact.FilterOptions           = crawlsAdminController{}
	_ pact.AdminPartialData        = crawlsAdminController{}
)