package server

import (
	"bytes"
	"context"
	"database/sql"
	"html/template"
	"io/fs"
	"log/slog"
	"net/http"
	"sort"
	"strconv"
	"strings"

	"git.coopcloud.tech/wiki-cafe/member-console/internal/auth"
	"git.coopcloud.tech/wiki-cafe/member-console/internal/billing"
	"git.coopcloud.tech/wiki-cafe/member-console/internal/config"
	"git.coopcloud.tech/wiki-cafe/member-console/internal/embeds"
	"git.coopcloud.tech/wiki-cafe/member-console/internal/entitlements"
	"git.coopcloud.tech/wiki-cafe/member-console/internal/identity"
	"git.coopcloud.tech/wiki-cafe/member-console/internal/integration"
	stripedb "git.coopcloud.tech/wiki-cafe/member-console/internal/integrations/stripe/store"
	"git.coopcloud.tech/wiki-cafe/member-console/internal/middleware"
	"git.coopcloud.tech/wiki-cafe/member-console/internal/organization"
	"github.com/spf13/viper"
)

// OperatorHandler handles the main operator page
type OperatorHandler struct {
	AuthConfig    *auth.Config
	Logger        *slog.Logger
	Templates     *SafeTemplates
	Database      *sql.DB // for the registry-driven Integration nav on the landing surface
	BillingQ      billing.Querier
	EntitlementsQ entitlements.Querier
	OrgQ          organization.Querier
	IdentityQ     identity.Querier
	// IntegrationQ backs the landing surface's System panel (registered
	// providers + outbox health). Derived from Database in the constructor;
	// a separate field so tests can inject a fake without a live database.
	IntegrationQ integration.Querier
	// IntegrationConfigs backs the System panel's configuration-readiness
	// signal (configurationReadiness) — the same declared-config list the
	// Integrations list and the per-integration settings page read.
	IntegrationConfigs []IntegrationConfigInfo
	// StripeQ backs the setup checklist's Stripe-price-mapping predicate
	// (AnyMappedPrice), composed with BillingQ.AnyActivePrice to derive the
	// conditional "sync a price to Stripe" step (setup_state.go). Derived
	// from Database in the constructor, matching IntegrationQ.
	StripeQ stripedb.Querier
}

// OperatorHandlerConfig holds configuration for the operator handler
type OperatorHandlerConfig struct {
	AuthConfig         *auth.Config
	Logger             *slog.Logger
	Database           *sql.DB
	BillingQ           billing.Querier
	EntitlementsQ      entitlements.Querier
	OrgQ               organization.Querier
	IdentityQ          identity.Querier
	IntegrationConfigs []IntegrationConfigInfo
}

// NewOperatorHandler creates a new OperatorHandler
func NewOperatorHandler(cfg OperatorHandlerConfig) (*OperatorHandler, error) {
	// Parse operator template
	templateSubFS, err := fs.Sub(embeds.Templates, "templates")
	if err != nil {
		return nil, err
	}

	// operator.html references the `renderBody` template func used by the
	// MPA page handlers' BodyTemplate dispatch. This handler now uses it too
	// (GetSetupPage, operator_setup.go), so — unlike the former no-op stub —
	// it must actually dispatch: look up the named template inside this same
	// set and render it. The closure captures `tmpl` (assigned below); funcs
	// must be installed before parsing so the parser accepts references to
	// "renderBody", so we pre-construct the empty template, install the
	// func, then ParseFS. Mirrors NewOperatorPartialsHandler's renderBody.
	// Also parses the lookup-result partial — operator.html `{{ template }}`s
	// it inline, and the OperatorLookup handler renders it standalone for
	// HTMX swap responses — and the setup-checklist partial, shared by the
	// landing region and GetSetupPage's BodyTemplate dispatch.
	var tmpl *template.Template
	tmpl = template.New("operator").Funcs(template.FuncMap{
		"renderBody": func(name string, data any) (template.HTML, error) {
			var buf bytes.Buffer
			if err := tmpl.ExecuteTemplate(&buf, name, data); err != nil {
				return "", err
			}
			return template.HTML(buf.String()), nil
		},
		"deploymentName": config.DeploymentName,
	})
	tmpl, err = tmpl.ParseFS(templateSubFS, "operator.html", "partials/operator_lookup_result.html", "partials/operator_setup.html")
	if err != nil {
		return nil, err
	}

	return &OperatorHandler{
		AuthConfig:         cfg.AuthConfig,
		Logger:             cfg.Logger,
		Templates:          NewSafeTemplates(tmpl, cfg.Logger),
		Database:           cfg.Database,
		BillingQ:           cfg.BillingQ,
		EntitlementsQ:      cfg.EntitlementsQ,
		OrgQ:               cfg.OrgQ,
		IdentityQ:          cfg.IdentityQ,
		IntegrationQ:       integration.New(cfg.Database),
		IntegrationConfigs: cfg.IntegrationConfigs,
		StripeQ:            stripedb.New(cfg.Database),
	}, nil
}

// RegisterRoutes registers operator routes
func (h *OperatorHandler) RegisterRoutes(mux *http.ServeMux) {
	mux.HandleFunc("GET /operator", h.requireOperatorRole(h.GetOperatorPage))
	mux.HandleFunc("POST /operator/lookup", h.requireOperatorRole(h.OperatorLookup))
	mux.HandleFunc("GET /operator/setup", h.requireOperatorRole(h.GetSetupPage))
}

// requireOperatorRole is middleware that checks for the operator role
func (h *OperatorHandler) requireOperatorRole(next http.HandlerFunc) http.HandlerFunc {
	return RequireOperatorRole(h.AuthConfig, h.Logger, next)
}

// RequireOperatorRole wraps next so it only runs for a request whose session
// holds the operator-member role; otherwise it responds 403 and logs the
// denial. Exported (beyond the OperatorHandler/OperatorPartialsHandler
// methods that delegate to it below) so an integration registering its own
// operator surface — design.md Decision 8; e.g.
// internal/integrations/fedwiki/web's read-only sites page — gates it with
// the same check core's operator pages use, instead of duplicating the
// role check inline.
func RequireOperatorRole(authConfig *auth.Config, logger *slog.Logger, next http.HandlerFunc) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		if !authConfig.HasRole(r, OperatorRole) {
			logger.Warn("operator access denied",
				slog.String("path", r.URL.Path),
				slog.String("reason", "missing operator-member role"))
			http.Error(w, "Forbidden", http.StatusForbidden)
			return
		}
		next(w, r)
	}
}

// OperatorPageData holds data for the operator page template.
type OperatorPageData struct {
	Name               string
	Username           string
	Email              string
	KeycloakAccountURL string
	CSRFToken          string
	// IAPosition is the positional tuple `<group>:<capability>[:<instance>]`
	// declared by every operator page per the breadcrumb requirement. The
	// landing surface declares `runtime:landing` since it sits in the
	// runtime group as the curated hot-path entry point.
	IAPosition string
	// ActiveCapability is the sidebar-link key the current page belongs to
	// ("organizations", "grants", ...). Drives the sidebar `active` class.
	// Empty on the landing surface (Overview light up).
	ActiveCapability string
	// BodyTemplate names the partial template to render inside <main>. When
	// non-empty the operator.html shell dispatches via renderBody; when
	// empty it renders the curated landing surface.
	BodyTemplate string
	BodyData     any
	// Activity is the unified-timeline rows for the landing surface's
	// "Recent activity" section (operator-composite-expansion D4).
	// Populated only on the landing branch; nil/empty on MPA pages.
	Activity []ActivityEvent
	// Overview holds the landing surface's "At a glance" counts and "System"
	// signals. Populated only on the landing branch; the zero value renders
	// the surface's empty states, which is what MPA pages get.
	Overview OverviewData
	// Setup is the setup checklist's derived state, shared by the landing
	// region (rendered here, ahead of Overview's tiles, only while
	// Setup.RequiredIncomplete) and GetSetupPage's full-page rendering
	// (setup_state.go, operator_setup.go). Populated only on the landing
	// branch; the zero value's RequiredIncomplete is false, so MPA pages
	// render no setup region (they have none to render).
	Setup SetupState
	// Lookup state for the landing-surface lookup affordance. LookupTerm
	// retains the operator's input on re-render so they can edit and
	// re-submit; LookupCandidates is populated on ambiguous matches;
	// LookupNoMatch is set on zero-match. Unique matches don't end up
	// here — they 303-redirect to the resolved detail page.
	LookupTerm       string
	LookupCandidates []LookupCandidateViewModel
	LookupNoMatch    bool
}

// LookupCandidateViewModel represents one candidate person in the
// disambiguation list rendered when a lookup term matches multiple
// persons by name substring.
type LookupCandidateViewModel struct {
	PersonID    string
	DisplayName string
	Email       string
}

// ActivityEvent is one row in the landing-surface unified timeline. Each
// row identifies its event type, the org (and person, when applicable),
// a short human summary, and a precomputed link target. Per D4 the
// template branches on EventType to render the right badge/icon — the
// loader doesn't pick visual styles, it picks data.
type ActivityEvent struct {
	EventType  string // "grant_issued" | "transition" | "invoice_created" | "payment_received"
	Timestamp  string // pre-formatted display string ("Jan 2, 2006 3:04 PM")
	SortKey    int64  // unix nanos, used to sort the merged slice
	OrgID      string
	OrgName    string
	PersonID   string // empty when no person attribution (system/webhook actor or billing event)
	PersonName string
	Summary    string // human-readable description of what happened
	// Href is the entry's own addressable operator surface (D8/task 7.4:
	// "feed entries link to their subjects where addressable"): the org
	// detail page for a grant or transition, the billing view for an
	// invoice or payment. Empty when the entry has no addressable surface —
	// the template renders those entries as plain text, never a dead link.
	Href string
}

// GetOperatorPage handles GET /operator
func (h *OperatorHandler) GetOperatorPage(w http.ResponseWriter, r *http.Request) {
	// Permanent redirect for legacy ?tab=<id> bookmarks. Slated for
	// removal in M8 once operator analytics show no remaining hits.
	if tab := r.URL.Query().Get("tab"); tab != "" {
		if redirect, ok := legacyTabRedirects[tab]; ok {
			http.Redirect(w, r, redirect, http.StatusMovedPermanently)
			return
		}
	}

	h.renderLanding(w, r, "", nil, false)
}

// OperatorLookup handles POST /operator/lookup — resolves the operator's
// typed lookup term to a person detail, an org composite, a disambiguation
// listing, or a no-match notice. Resolution order:
//  1. email-exact + name-substring against active persons (one query); if
//     one match → HX-Redirect to person detail; if many → render the
//     result partial with the disambiguation list (HTMX swap).
//  2. org slug exact; if found → HX-Redirect to org composite.
//  3. otherwise → render the result partial with a no-match notice.
//
// HTMX (hx-post on the form) handles the X-CSRF-Token header via the
// body's hx-headers; this is the same CSRF path every other operator
// form uses. Native form POST hit a brittle Origin-check path in
// gorilla CSRF for some browsers (origin=null on certain submissions),
// so we route through HTMX instead.
func (h *OperatorHandler) OperatorLookup(w http.ResponseWriter, r *http.Request) {
	if err := r.ParseForm(); err != nil {
		h.renderLookupResult(w, "", nil, true)
		return
	}
	term := strings.TrimSpace(r.FormValue("term"))
	if term == "" {
		// Empty submit: nothing to render. Return empty body so HTMX clears
		// any previous result without showing a state.
		h.renderLookupResult(w, "", nil, false)
		return
	}

	ctx := r.Context()
	persons, err := h.IdentityQ.LookupPersons(ctx, term)
	if err != nil {
		h.Logger.Warn("lookup: persons query failed", slog.Any("error", err))
	}
	switch len(persons) {
	case 1:
		w.Header().Set("HX-Redirect", "/operator/persons/"+persons[0].PersonID)
		w.WriteHeader(http.StatusOK)
		return
	case 0:
		// Fall through to org-slug check.
	default:
		candidates := make([]LookupCandidateViewModel, len(persons))
		for i, p := range persons {
			candidates[i] = LookupCandidateViewModel{
				PersonID:    p.PersonID,
				DisplayName: p.DisplayName,
				Email:       p.PrimaryEmail,
			}
		}
		h.renderLookupResult(w, term, candidates, false)
		return
	}

	if org, err := h.OrgQ.GetOrganizationBySlug(ctx, term); err == nil {
		w.Header().Set("HX-Redirect", "/operator/organizations/"+org.OrgID)
		w.WriteHeader(http.StatusOK)
		return
	}

	h.renderLookupResult(w, term, nil, true)
}

// renderLookupResult renders the lookup-result partial for HTMX swap.
// `term` populates the no-match alert / disambiguation header; `candidates`
// drives the person picker; `noMatch` triggers the warning alert.
func (h *OperatorHandler) renderLookupResult(w http.ResponseWriter, term string, candidates []LookupCandidateViewModel, noMatch bool) {
	data := struct {
		LookupTerm       string
		LookupCandidates []LookupCandidateViewModel
		LookupNoMatch    bool
	}{
		LookupTerm:       term,
		LookupCandidates: candidates,
		LookupNoMatch:    noMatch,
	}
	h.Templates.Render(w, "operator_lookup_result.html", data)
}

// renderLanding renders the operator landing surface with optional lookup
// state. `lookupTerm` populates the form input on re-render so the
// operator can edit and resubmit; `candidates` triggers the disambiguation
// list; `noMatch` triggers the no-match notice. All three are off on a
// plain landing render.
func (h *OperatorHandler) renderLanding(w http.ResponseWriter, r *http.Request, lookupTerm string, candidates []LookupCandidateViewModel, noMatch bool) {
	ctx := r.Context()
	limit := parseActivityLimit(r.URL.Query().Get("limit"))
	data := OperatorPageData{
		Name:               h.AuthConfig.GetUserName(ctx),
		Username:           h.AuthConfig.GetUsername(ctx),
		Email:              h.AuthConfig.GetUserEmail(ctx),
		KeycloakAccountURL: viper.GetString("oidc-idp-issuer-url") + "/account",
		CSRFToken:          middleware.CSRFToken(r),
		IAPosition:         "runtime:landing",
		Overview:           h.loadOverview(ctx),
		Setup:              h.DeriveSetupState(ctx),
		Activity:           h.loadRecentActivity(ctx, limit),
		LookupTerm:         lookupTerm,
		LookupCandidates:   candidates,
		LookupNoMatch:      noMatch,
	}
	h.Templates.Render(w, "operator.html", data)
}

// parseActivityLimit clamps the ?limit=N param to [1, 100] with a default
// of 20. Per D4 the activity feed is one unified timeline and one knob —
// no separate ?activity_limit / ?billing_limit splits.
func parseActivityLimit(raw string) int32 {
	const defaultLimit, maxLimit = 20, 100
	if raw == "" {
		return defaultLimit
	}
	n, err := strconv.Atoi(raw)
	if err != nil || n < 1 {
		return defaultLimit
	}
	if n > maxLimit {
		return maxLimit
	}
	return int32(n)
}

// loadRecentActivity assembles the landing-surface unified timeline by
// fetching `limit` rows from each event source (grants, transitions,
// invoices, payments), resolving org and person UUIDs to display names,
// then merging by timestamp DESC and trimming back to `limit`. Per-source
// over-fetch + post-merge trim is correct because no single source's
// recent N rows are guaranteed to be the global recent N.
//
// Failures from any individual source are logged and the source is
// dropped — the timeline degrades gracefully rather than 500ing the
// landing surface. An empty result is the legitimate empty state.
func (h *OperatorHandler) loadRecentActivity(ctx context.Context, limit int32) []ActivityEvent {
	events := make([]ActivityEvent, 0, int(limit)*4)

	if grants, err := h.EntitlementsQ.ListRecentGrants(ctx, limit); err == nil {
		for _, g := range grants {
			orgID := ""
			if g.GrantedToOrgID.Valid {
				orgID = g.GrantedToOrgID.UUID.String()
			}
			personID := ""
			if g.GrantedByPersonID.Valid {
				personID = g.GrantedByPersonID.UUID.String()
			}
			productName := ""
			if p, err := h.BillingQ.GetProductByID(ctx, g.ProductID); err == nil {
				productName = p.Name
			}
			events = append(events, ActivityEvent{
				EventType: "grant_issued",
				Timestamp: g.CreatedAt.Format("Jan 2, 2006 3:04 PM"),
				SortKey:   g.CreatedAt.UnixNano(),
				OrgID:     orgID,
				PersonID:  personID,
				Summary:   "Issued " + productName + " (" + g.GrantReason + ")",
				Href:      "/operator/organizations/" + orgID,
			})
		}
	} else {
		h.Logger.Warn("activity feed: list recent grants failed", slog.Any("error", err))
	}

	if transitions, err := h.EntitlementsQ.ListRecentTransitions(ctx, limit); err == nil {
		for _, t := range transitions {
			personID := ""
			if t.ActorID.Valid {
				personID = t.ActorID.UUID.String()
			}
			from := "—"
			if t.FromRank.Valid {
				from = strconv.Itoa(int(t.FromRank.Int32))
			}
			to := "—"
			if t.ToRank.Valid {
				to = strconv.Itoa(int(t.ToRank.Int32))
			}
			events = append(events, ActivityEvent{
				EventType: "transition",
				Timestamp: t.EffectiveAt.Format("Jan 2, 2006 3:04 PM"),
				SortKey:   t.EffectiveAt.UnixNano(),
				OrgID:     t.OrgID,
				PersonID:  personID,
				Summary:   t.TransitionType + " (rank " + from + " → " + to + ", by " + t.ActorType + ")",
				Href:      "/operator/organizations/" + t.OrgID,
			})
		}
	} else {
		h.Logger.Warn("activity feed: list recent transitions failed", slog.Any("error", err))
	}

	if invoices, err := h.BillingQ.ListRecentInvoices(ctx, limit); err == nil {
		for _, inv := range invoices {
			events = append(events, ActivityEvent{
				EventType: "invoice_created",
				Timestamp: inv.CreatedAt.Format("Jan 2, 2006 3:04 PM"),
				SortKey:   inv.CreatedAt.UnixNano(),
				OrgID:     inv.OrgID,
				Summary:   "Invoice " + formatCurrency(inv.AmountDue, inv.Currency) + " · " + inv.Status,
				Href:      "/operator/billing/invoices",
			})
		}
	} else {
		h.Logger.Warn("activity feed: list recent invoices failed", slog.Any("error", err))
	}

	if payments, err := h.BillingQ.ListRecentPayments(ctx, limit); err == nil {
		for _, p := range payments {
			events = append(events, ActivityEvent{
				EventType: "payment_received",
				Timestamp: p.CreatedAt.Format("Jan 2, 2006 3:04 PM"),
				SortKey:   p.CreatedAt.UnixNano(),
				OrgID:     p.OrgID,
				Summary:   "Payment " + formatCurrency(p.Amount, p.Currency) + " · " + p.Status,
				Href:      "/operator/billing/payments",
			})
		}
	} else {
		h.Logger.Warn("activity feed: list recent payments failed", slog.Any("error", err))
	}

	// Merge by timestamp DESC, then trim to limit.
	sort.Slice(events, func(i, j int) bool { return events[i].SortKey > events[j].SortKey })
	if int32(len(events)) > limit {
		events = events[:limit]
	}

	// Resolve org and person display names in a second pass. Per-row
	// lookups would be N+1 — collect distinct IDs first, then map.
	orgNames := make(map[string]string)
	personNames := make(map[string]string)
	for _, e := range events {
		if e.OrgID != "" {
			orgNames[e.OrgID] = ""
		}
		if e.PersonID != "" {
			personNames[e.PersonID] = ""
		}
	}
	for orgID := range orgNames {
		if o, err := h.OrgQ.GetOrganizationByID(ctx, orgID); err == nil {
			orgNames[orgID] = o.Name
		}
	}
	for personID := range personNames {
		if p, err := h.IdentityQ.GetPersonByID(ctx, personID); err == nil {
			personNames[personID] = p.DisplayName
		}
	}
	for i := range events {
		events[i].OrgName = orgNames[events[i].OrgID]
		events[i].PersonName = personNames[events[i].PersonID]
	}

	return events
}

// legacyTabRedirects maps retired ?tab=<id> bookmarks to their replacement
// MPA route. Scheduled for removal in M8 — see openspec change
// operator-mpa-conversion task 6.2.
var legacyTabRedirects = map[string]string{
	"orgs":             "/operator/organizations",
	"organizations":    "/operator/organizations",
	"grants":           "/operator/grants",
	"billing":          "/operator/billing/accounts",
	"org-types":        "/operator/org-types",
	"products":         "/operator/products",
	"entitlement-sets": "/operator/entitlement-sets",
	"plan-ladders":     "/operator/plan-ladders",
	// Persons has no browse route per design D4. tab=people bookmarks
	// land on the operator landing surface, where the lookup affordance
	// will route them to the per-person detail page.
	"people": "/operator",
	// "sites" (the legacy FedWiki sites tab) is intentionally absent: its
	// destination is now an integration-registered route (design.md
	// Decision 8; see internal/integrations/fedwiki/web), and core must
	// not hardcode an integration-specific path here to redirect to it
	// (openspec/changes/integration-extraction task 2.7). A ?tab=sites
	// bookmark now falls through to the landing surface below rather than
	// resolving to a specific redirect — acceptable since this whole map
	// is already slated for removal (operator-mpa-conversion task 6.2).
}