// Package static implements the "static" source: a git-folder-backed
// deployable that can serve plain files or run a Deno backend. Builds an
// image from the cloned folder and runs one container.
//
// The full deploy pipeline lives in internal/staticsite (git providers,
// markdown rendering, Dockerfile codegen, Deno scaffolding, image build,
// proxy registration) and is wired in via a function variable so that
// neither this package nor staticsite has to depend on the other.
//
// cmd/server/main.go (or any caller with access to both packages)
// populates DeployFn / TeardownFn / ReconcileFn at startup; until then,
// Source methods return an explicit error so misconfiguration surfaces
// loudly instead of silently failing.
package static

import (
	"context"
	"encoding/json"
	"fmt"
	"strings"
	"sync"
	"sync/atomic"

	"github.com/alexei/tinyforge/internal/workload/plugin"
)

// Config is the per-workload source config blob. Mirrors the fields that
// used to live on the static_sites table, less anything moved to Workload
// (notification config, webhook secrets, public_face).
type Config struct {
	Provider       string `json:"provider"`         // "gitea" | "github" | "gitlab"; "" = autodetect
	BaseURL        string `json:"base_url"`         // e.g. https://git.example.com
	RepoOwner      string `json:"repo_owner"`
	RepoName       string `json:"repo_name"`
	Branch         string `json:"branch"`
	FolderPath     string `json:"folder_path"`      // path within repo
	AccessToken    string `json:"access_token"`     // encrypted; optional for public repos
	Mode           string `json:"mode"`             // "static" | "deno"
	RenderMarkdown bool   `json:"render_markdown"`
	StorageEnabled bool   `json:"storage_enabled"`
	StorageLimitMB int    `json:"storage_limit_mb"`
}

// Backend captures the deploy lifecycle of a static site. main.go wires
// an implementation that adapts internal/staticsite.Manager to this
// interface; the plugin contract sees only this shape so it stays
// independent of any specific manager type.
type Backend interface {
	Deploy(ctx context.Context, deps plugin.Deps, w plugin.Workload, intent plugin.DeploymentIntent) error
	Teardown(ctx context.Context, deps plugin.Deps, w plugin.Workload) error
	Reconcile(ctx context.Context, deps plugin.Deps, w plugin.Workload) error
}

var (
	backendMu  sync.RWMutex
	backend    Backend
	backendSet atomic.Bool
)

// SetBackend wires the staticsite-package adapter into this Source AND
// registers the source with the plugin registry. MUST be called exactly
// once from cmd/server/main.go before any plugin invocation. Subsequent
// calls panic — a swapped backend at runtime is a trust-boundary
// inversion (a future plugin loaded via blank import could replace
// deploy/teardown logic that handles git tokens).
func SetBackend(b Backend) {
	if !backendSet.CompareAndSwap(false, true) {
		panic("static: backend already wired (SetBackend may be called once)")
	}
	backendMu.Lock()
	backend = b
	backendMu.Unlock()
	plugin.RegisterSource(&source{})
}

func currentBackend() (Backend, error) {
	backendMu.RLock()
	defer backendMu.RUnlock()
	if backend == nil {
		return nil, fmt.Errorf("static source: backend not wired; call static.SetBackend from main.go")
	}
	return backend, nil
}

type source struct{}

// Static source registers itself only after SetBackend is called from
// main.go. Eager init() registration would advertise "static" via
// /api/hooks/kinds before there is anything to dispatch to — frontends
// would render it in pickers and operators would hit "backend not wired"
// at deploy time. Lazy registration keeps the kind invisible until it's
// actually usable.

func (*source) Kind() string { return "static" }

func (*source) SchemaSample() any {
	return Config{
		Provider:   "gitea",
		BaseURL:    "https://git.example.com",
		RepoOwner:  "owner",
		RepoName:   "pages",
		Branch:     "main",
		FolderPath: "",
		Mode:       "static",
	}
}

func (*source) Validate(cfg json.RawMessage) error {
	var c Config
	if len(cfg) == 0 {
		return fmt.Errorf("static source: config is required")
	}
	if err := json.Unmarshal(cfg, &c); err != nil {
		return fmt.Errorf("static source: invalid json: %w", err)
	}
	if strings.TrimSpace(c.RepoOwner) == "" || strings.TrimSpace(c.RepoName) == "" {
		return fmt.Errorf("static source: repo_owner and repo_name are required")
	}
	if c.Mode != "" && c.Mode != "static" && c.Mode != "deno" {
		return fmt.Errorf("static source: mode must be \"static\" or \"deno\"")
	}
	return nil
}

func (*source) Deploy(ctx context.Context, deps plugin.Deps, w plugin.Workload, intent plugin.DeploymentIntent) error {
	b, err := currentBackend()
	if err != nil {
		return err
	}
	return b.Deploy(ctx, deps, w, intent)
}

func (*source) Teardown(ctx context.Context, deps plugin.Deps, w plugin.Workload) error {
	b, err := currentBackend()
	if err != nil {
		return err
	}
	return b.Teardown(ctx, deps, w)
}

func (*source) Reconcile(ctx context.Context, deps plugin.Deps, w plugin.Workload) error {
	b, err := currentBackend()
	if err != nil {
		return err
	}
	return b.Reconcile(ctx, deps, w)
}