package modules

import (
	"context"

	"github.com/go-telegram/bot"
	"github.com/go-telegram/bot/models"

	"github.com/tiennm99/miti99bot/internal/storage"
)

// Visibility classifies who may invoke a command. The dispatcher enforces
// this at command-handler entry: Public is unrestricted; Protected requires
// the sender to be in Auth.AdminUserIDs (or be the bot owner); Private
// requires the sender to be Auth.BotOwnerID. /help filters by the same field.
type Visibility int

const (
	VisibilityPublic Visibility = iota
	VisibilityProtected
	VisibilityPrivate
)

// CommandHandler runs in response to a Telegram command. Returning an error
// causes the dispatcher to log the failure. Telegram retries are governed by
// the webhook HTTP status (200), not handler errors — so the error return is
// purely for logging/metrics, not flow control.
type CommandHandler func(ctx context.Context, b *bot.Bot, update *models.Update) error

// CallbackHandler runs in response to inline-keyboard callback data. Callback
// payloads are not commands and therefore do not participate in command stats.
type CallbackHandler func(ctx context.Context, b *bot.Bot, update *models.Update) error

// Callback registers an inline-keyboard callback-data prefix owned by a module.
// Prefixes must be globally non-overlapping so one callback reaches one owner.
type Callback struct {
	Prefix     string
	Visibility Visibility
	Handler    CallbackHandler
}

// CronHandler runs when a cron fires — driven by the in-process scheduler
// (internal/cron) on self-host, or by a POST to /cron/{name} for manual
// triggers. Crons receive the per-module-prefixed Deps via the registry;
// handlers should not capture the base Deps from the factory closure or KV
// writes will collide across modules.
type CronHandler func(ctx context.Context, deps Deps) error

// Command is a single Telegram bot command exposed by a module.
type Command struct {
	Name        string         // ^[a-z0-9_]{1,32}$ — Telegram BotFather rules
	Visibility  Visibility     // public/protected/private
	Description string         // concise summary shown in command discovery (required, non-empty)
	Parameters  string         // optional syntax after the command, e.g. "<quantity> <ticker>"
	Handler     CommandHandler // required
}

// Cron is a single scheduled job exposed by a module.
type Cron struct {
	Schedule string      // 5-field cron expr (UTC); the in-process scheduler fires the handler on it
	Name     string      // unique within module
	Handler  CronHandler // required
}

// Module is a self-contained feature unit: a name plus zero or more commands
// and crons. Modules are constructed by Factory functions that capture their
// per-module Deps via closure.
//
// Module.Name is overridden by the registry to its catalog key; factories may
// leave it blank.
type Module struct {
	Name        string
	Commands    []Command
	Callbacks   []Callback
	Crons       []Cron
	CommandHook func(ctx context.Context, name string, update *models.Update) // optional; called by dispatcher after each authorized command invocation. update carries the originating Telegram update so hooks can attribute usage to a user.
}

// Deps is the dependency bundle a Factory receives.
//
// Deps.Registry is a pointer to the Registry being built. At factory call
// time the Registry is partially populated (only modules earlier in the
// MODULES env order); by the time any handler runs, it is fully populated.
// Modules that need to introspect commands (e.g. /help) capture this pointer
// in their handler closures.
type Deps struct {
	Store    storage.Collection // the module's own collection; build typed views with storage.Typed[T]
	Registry *Registry          // populated by Build; safe to capture but read-only at module use
	Bot      *bot.Bot           // nil-safe: only crons that fan-out (lol daily push) need it
}

// Factory constructs a Module from its Deps. Deps are passed directly (instead
// of a separate Init step) so handler closures can capture them — idiomatic Go
// and removes a lifecycle ordering trap.
type Factory func(deps Deps) Module