// Package sandbox — runner.go
//
// v0.29.0 CS3: Runner loads a package's Starlark script, assembles
// the module set based on granted permissions, and executes it.
//
// v0.29.1 CS0: Wires api.http permission to BuildHTTPModule with
// network_access config from package manifest.
//
// v0.29.1 CS2: Adds RunContext for per-invocation state (user_id),
// vault for provider key decryption, and provider.complete module.
//
// v0.29.2 CS1: Adds db *sql.DB for the db module. SetDB() wires it
// at startup. db.read grants query/view/list_tables; db.write adds
// insert/update/delete. If both are granted, db.write wins (superset).
//
// The runner is the bridge between the package/permission system
// and the sandboxed Starlark interpreter.
package sandbox

import (
	"context"
	"database/sql"
	"fmt"
	"log"

	"go.starlark.net/starlark"

	"chat-switchboard/models"
	"chat-switchboard/store"
)

// RunContext carries per-invocation state that modules need but which
// varies per caller (API route vs filter vs task). Nil is safe — modules
// that need RunContext fields gracefully degrade.
type RunContext struct {
	// UserID is the acting user for provider resolution (BYOK chain).
	UserID string

	// ChannelID is the channel context, if any. Used for provider
	// resolution when a channel has a pinned provider config.
	ChannelID string
}

// Runner executes Starlark package scripts with permission-gated modules.
type Runner struct {
	sandbox    *Sandbox
	stores     store.Stores
	notifier   NotificationSender // nil = notifications module unavailable
	resolver   ProviderResolver   // nil = provider module unavailable
	db         *sql.DB            // nil = db module unavailable
	dbPostgres bool               // true = use $N placeholders; false = use ?
}

// NewRunner creates a runner with the given sandbox and dependencies.
func NewRunner(sb *Sandbox, stores store.Stores) *Runner {
	return &Runner{
		sandbox: sb,
		stores:  stores,
	}
}

// SetNotifier attaches the notification sender for the notifications module.
func (r *Runner) SetNotifier(n NotificationSender) {
	r.notifier = n
}

// SetProviderResolver attaches the provider resolver for the provider.complete module.
func (r *Runner) SetProviderResolver(pr ProviderResolver) {
	r.resolver = pr
}

// SetDB attaches the raw database connection for the db module.
// isPostgres controls whether $N or ? placeholders are used.
// Call this at startup after database.Connect().
func (r *Runner) SetDB(db *sql.DB, isPostgres bool) {
	r.db = db
	r.dbPostgres = isPostgres
}

// ExecPackage loads a package's script from its manifest and executes it
// with modules gated by the package's granted permissions.
//
// The RunContext carries per-invocation state (user_id for provider
// resolution). Pass nil if no per-invocation context is needed.
//
// Returns the script's globals (which may contain callable entry points
// like on_pre_completion, on_run, etc.) and any captured print output.
func (r *Runner) ExecPackage(ctx context.Context, pkg *store.PackageRegistration, rc *RunContext) (*Result, error) {
	// Only active starlark packages can execute
	if pkg.Status != models.PackageStatusActive {
		return nil, fmt.Errorf("package %q is %s, not active", pkg.ID, pkg.Status)
	}
	if pkg.Tier != models.ExtTierStarlark {
		return nil, fmt.Errorf("package %q is tier %s, not starlark", pkg.ID, pkg.Tier)
	}

	// Extract script from manifest
	script, ok := pkg.Manifest["_starlark_script"].(string)
	if !ok || script == "" {
		return nil, fmt.Errorf("package %q has no _starlark_script in manifest", pkg.ID)
	}

	// Build modules based on granted permissions
	modules, err := r.buildModules(ctx, pkg.ID, pkg.Manifest, rc)
	if err != nil {
		return nil, fmt.Errorf("failed to build modules for %q: %w", pkg.ID, err)
	}

	log.Printf("  🔧 runner: exec %s (%d modules granted)", pkg.ID, len(modules))

	return r.sandbox.Exec(ctx, pkg.ID+".star", script, modules)
}

// CallEntryPoint executes a package script and calls a named function.
// This is the standard pattern for event-driven extensions:
//  1. Exec the script (defines functions)
//  2. Find the named entry point in globals
//  3. Call it with the provided arguments
//
// The RunContext carries per-invocation state. Pass nil if not needed.
//
// Returns the function's return value and captured output.
func (r *Runner) CallEntryPoint(ctx context.Context, pkg *store.PackageRegistration, entryPoint string, args starlark.Tuple, kwargs []starlark.Tuple, rc *RunContext) (starlark.Value, string, error) {
	result, err := r.ExecPackage(ctx, pkg, rc)
	if err != nil {
		return nil, "", err
	}

	fn, ok := result.Globals[entryPoint]
	if !ok {
		return nil, result.Output, fmt.Errorf("package %q has no %s function", pkg.ID, entryPoint)
	}

	callable, ok := fn.(starlark.Callable)
	if !ok {
		return nil, result.Output, fmt.Errorf("package %q: %s is not callable", pkg.ID, entryPoint)
	}

	val, callOutput, err := r.sandbox.Call(ctx, callable, args, kwargs)
	return val, result.Output + callOutput, err
}

// buildModules assembles the module map based on granted permissions.
// The manifest is passed through so modules can read their config
// (e.g., http module reads network_access, provider reads requires_provider).
// The RunContext carries per-invocation state for user-scoped modules.
func (r *Runner) buildModules(ctx context.Context, packageID string, manifest map[string]any, rc *RunContext) (map[string]starlark.Value, error) {
	if r.stores.ExtPermissions == nil {
		return nil, nil
	}

	granted, err := r.stores.ExtPermissions.GrantedForPackage(ctx, packageID)
	if err != nil {
		return nil, err
	}

	modules := make(map[string]starlark.Value)

	// Track db permission level: 0=none, 1=read, 2=write
	dbLevel := 0

	for _, perm := range granted {
		switch perm {
		case models.ExtPermSecretsRead:
			modules["secrets"] = BuildSecretsModule(ctx, r.stores, packageID)

		case models.ExtPermNotificationsSend:
			if r.notifier != nil {
				modules["notifications"] = BuildNotificationsModule(ctx, r.notifier, packageID)
			}

		case models.ExtPermAPIHTTP:
			httpCfg := ParseNetworkAccess(manifest)
			modules["http"] = BuildHTTPModule(ctx, httpCfg)

		case models.ExtPermProviderComplete:
			if r.resolver != nil && rc != nil && rc.UserID != "" {
				provCfg, ok := ParseRequiresProvider(manifest)
				if ok {
					modules["provider"] = BuildProviderModule(ctx, r.resolver, rc.UserID, provCfg)
				}
			}

		case models.ExtPermDBRead:
			if dbLevel < 1 {
				dbLevel = 1
			}

		case models.ExtPermDBWrite:
			dbLevel = 2

		case models.ExtPermWorkflowAccess:
			modules["workflow"] = BuildWorkflowModule(ctx, r.stores)
		}
	}

	// Wire db module at the highest granted level.
	if dbLevel > 0 && r.db != nil {
		modules["db"] = BuildDBModule(ctx, DBModuleConfig{
			PackageID:  packageID,
			CanWrite:   dbLevel == 2,
			DB:         r.db,
			IsPostgres: r.dbPostgres,
		})
	}

	// v0.30.0: settings module — always injected, no permission required.
	// A package reads its own admin + user settings.
	userID := ""
	if rc != nil {
		userID = rc.UserID
	}
	modules["settings"] = BuildSettingsModule(ctx, r.stores, packageID, userID)

	return modules, nil
}
