package onboarding

import (
	"context"
	"embed"
	"encoding/json"
	"errors"
	"fmt"
	"sort"
	"strings"

	"github.com/itworx/pulse/internal/alert"
	"github.com/itworx/pulse/internal/dashboard"
	"github.com/jackc/pgx/v5/pgxpool"
)

//go:embed default-dashboard.json
var defaultDashboardFS embed.FS

type Service struct {
	State        StateStore
	Pool         *pgxpool.Pool
	Dashboards   dashboard.Repository
	Alerts       alert.Store
	AuthMode     string
	OIDCIssuer   string
	OIDCClient   string
	OIDCRedirect string
	Prometheus   bool
	Unraid       bool
	// RuntimeCapabilities supplies observed source readiness. It overrides the
	// configuration-only Prometheus and Unraid placeholders when present.
	RuntimeCapabilities func(context.Context) ([]Capability, error)
}

func (s Service) Status(ctx context.Context) (Status, error) {
	state, err := s.State.Load(ctx)
	if err != nil {
		return Status{}, err
	}
	caps := make([]Capability, 0, 7)
	if s.Pool == nil {
		caps = append(caps, Capability{ID: "database", State: "unavailable", Detail: "De database is niet geconfigureerd."})
	} else if err := s.Pool.Ping(ctx); err != nil {
		caps = append(caps, Capability{ID: "database", State: "unknown", Detail: "De database is niet bereikbaar."})
	} else {
		caps = append(caps, Capability{ID: "database", State: "ready", Detail: "De database is beschikbaar."})
	}
	if s.Prometheus {
		caps = append(caps, Capability{ID: "prometheus", State: "configured", Detail: "Prometheus is geconfigureerd; de endpoint blijft verborgen."})
	} else {
		caps = append(caps, Capability{ID: "prometheus", State: "unknown", Detail: "Prometheus is nog niet geconfigureerd."})
	}
	if s.Unraid {
		caps = append(caps, Capability{ID: "unraid", State: "configured", Detail: "De read-only Unraid-bron is geconfigureerd."})
	} else {
		caps = append(caps, Capability{ID: "unraid", State: "unknown", Detail: "De read-only Unraid-bron is nog niet geconfigureerd."})
	}
	if s.Pool == nil {
		caps = append(caps, Capability{ID: "services", State: "unavailable", Detail: "Servicebewaking is niet beschikbaar zonder database."})
	} else {
		var enabled int
		if err := s.Pool.QueryRow(ctx, `SELECT count(*) FROM probes WHERE enabled=true AND archived_at IS NULL`).Scan(&enabled); err != nil {
			caps = append(caps, Capability{ID: "services", State: "unknown", Detail: "De actieve servicechecks konden niet worden gelezen."})
		} else if enabled == 0 {
			caps = append(caps, Capability{ID: "services", State: "not-ready", Detail: "Er zijn nog geen veilige servicechecks geconfigureerd."})
		} else {
			caps = append(caps, Capability{ID: "services", State: "ready", Detail: fmt.Sprintf("%d veilige read-only servicechecks zijn actief.", enabled)})
		}
	}
	switch {
	case s.AuthMode == "mock":
		caps = append(caps, Capability{ID: "auth", State: "development", Detail: "Mock-authenticatie is actief voor development."})
	case strings.TrimSpace(s.OIDCIssuer) != "" && strings.TrimSpace(s.OIDCClient) != "" && strings.TrimSpace(s.OIDCRedirect) != "":
		caps = append(caps, Capability{ID: "auth", State: "ready", Detail: "OIDC-configuratie is compleet; secrets worden niet getoond."})
	default:
		caps = append(caps, Capability{ID: "auth", State: "incomplete", Detail: "OIDC-configuratie is nog niet compleet."})
	}
	if s.Alerts == nil {
		caps = append(caps, Capability{ID: "default-rules", State: "unavailable", Detail: "De alertregels zijn niet beschikbaar."})
	} else if rules, listErr := s.Alerts.List(ctx, 100); listErr != nil {
		caps = append(caps, Capability{ID: "default-rules", State: "unknown", Detail: "De alertregels konden niet worden gelezen."})
	} else if len(rules) == 0 {
		caps = append(caps, Capability{ID: "default-rules", State: "not-ready", Detail: "Er zijn nog geen alertregels beschikbaar."})
	} else {
		caps = append(caps, Capability{ID: "default-rules", State: "ready", Detail: fmt.Sprintf("%d alertregels zijn beschikbaar.", len(rules))})
	}
	if state.DashboardID != "" {
		caps = append(caps, Capability{ID: "default-dashboard", State: "ready", Detail: "Het standaarddashboard is geselecteerd."})
	} else {
		caps = append(caps, Capability{ID: "default-dashboard", State: "not-ready", Detail: "Het standaarddashboard is nog niet geselecteerd."})
	}
	if s.RuntimeCapabilities != nil {
		observed, observedErr := s.RuntimeCapabilities(ctx)
		if observedErr != nil {
			return Status{}, fmt.Errorf("read runtime capabilities: %w", observedErr)
		}
		caps = mergeCapabilities(caps, observed)
	}
	sort.Slice(caps, func(i, j int) bool { return caps[i].ID < caps[j].ID })
	return Status{State: state, Capabilities: caps, Resume: !state.Completed && state.Step != "" && state.Step != "welcome"}, nil
}

func mergeCapabilities(configured, observed []Capability) []Capability {
	byID := make(map[string]Capability, len(configured)+len(observed))
	for _, capability := range configured {
		byID[capability.ID] = capability
	}
	for _, capability := range observed {
		if capability.ID == "prometheus" || capability.ID == "unraid" {
			byID[capability.ID] = capability
		}
	}
	result := make([]Capability, 0, len(byID))
	for _, capability := range byID {
		result = append(result, capability)
	}
	return result
}

func (s Service) Complete(ctx context.Context, choice Choice) (Status, error) {
	if choice.Dashboard == "" {
		choice.Dashboard = "default"
	}
	if choice.Rules == "" {
		choice.Rules = "default"
	}
	if !validChoice(choice.Dashboard) || !validChoice(choice.Rules) {
		return Status{}, errors.New("onboarding choices must be default or skip")
	}
	state, err := s.State.Load(ctx)
	if err != nil {
		return Status{}, err
	}
	state.DashboardChoice = choice.Dashboard
	state.RulesChoice = choice.Rules
	state.Step = "dashboard"
	if err := s.State.Save(ctx, state); err != nil {
		return Status{}, err
	}
	if choice.Dashboard == "default" {
		if state.DashboardID == "" {
			id, ensureErr := s.ensureDefaultDashboard(ctx)
			if ensureErr != nil {
				return Status{}, ensureErr
			}
			state.DashboardID = id
		}
	}
	state.Step = "rules"
	if err := s.State.Save(ctx, state); err != nil {
		return Status{}, err
	}
	if s.Alerts != nil {
		rules, listErr := s.Alerts.List(ctx, 100)
		if listErr != nil {
			return Status{}, fmt.Errorf("read default alert rules: %w", listErr)
		}
		state.RulesReady = len(rules) > 0
	}
	if choice.Rules == "default" && !state.RulesReady {
		return Status{}, errors.New("default alert rules are not ready")
	}
	state.Completed = true
	state.Step = "complete"
	if err := s.State.Save(ctx, state); err != nil {
		return Status{}, err
	}
	return s.Status(ctx)
}

func validChoice(value string) bool { return value == "default" || value == "skip" }

func (s Service) ensureDefaultDashboard(ctx context.Context) (string, error) {
	if s.Dashboards.Pool == nil {
		return "", errors.New("dashboard repository is not configured")
	}
	items, err := s.Dashboards.List(ctx, "onboarding", 100)
	if err != nil {
		return "", fmt.Errorf("find default dashboard: %w", err)
	}
	for _, item := range items {
		if item.Slug == DefaultSlug && item.ArchivedAt == nil {
			return item.ID, nil
		}
	}
	document, err := defaultDashboard()
	if err != nil {
		return "", err
	}
	created, _, err := s.Dashboards.Create(ctx, "system-defaults", document, "first-run default dashboard")
	if err != nil {
		if errors.Is(err, dashboard.ErrConflict) {
			items, listErr := s.Dashboards.List(ctx, "onboarding", 100)
			if listErr == nil {
				for _, item := range items {
					if item.Slug == DefaultSlug && item.ArchivedAt == nil {
						return item.ID, nil
					}
				}
			}
		}
		return "", fmt.Errorf("install default dashboard: %w", err)
	}
	return created.ID, nil
}

func defaultDashboard() (dashboard.Document, error) {
	raw, err := defaultDashboardFS.ReadFile("default-dashboard.json")
	if err != nil {
		return nil, fmt.Errorf("read embedded default dashboard: %w", err)
	}
	var document dashboard.Document
	if err := json.Unmarshal(raw, &document); err != nil {
		return nil, fmt.Errorf("decode embedded default dashboard: %w", err)
	}
	migrated, err := dashboard.Migrate(document)
	if err != nil {
		return nil, fmt.Errorf("validate embedded default dashboard: %w", err)
	}
	return migrated, nil
}