[templating] Add multiply and seededRandom template functions

Signed-off-by: Knut Ahlers <knut@ahlers.me>

internal/template/numeric/numeric.go

@@ -0,0 +1,10 @@
+package numeric
+
+import "github.com/Luzifer/twitch-bot/plugins"
+
+func Register(args plugins.RegistrationArguments) error {
+	args.RegisterTemplateFunction("multiply", plugins.GenericTemplateFunctionGetter(multiply))
+	return nil
+}
+
+func multiply(m1, m2 float64) float64 { return m1 * m2 }

internal/template/random/random.go

@@ -0,0 +1,43 @@
+package random
+
+import (
+	"crypto/md5" // #nosec G501 // Unly used to convert a string into a numer, no need for cryptographic safety
+	"fmt"
+	"math"
+	"math/rand"
+
+	"github.com/Luzifer/twitch-bot/plugins"
+	"github.com/pkg/errors"
+)
+
+func Register(args plugins.RegistrationArguments) error {
+	args.RegisterTemplateFunction("seededRandom", plugins.GenericTemplateFunctionGetter(stableRandomFromSeed))
+	return nil
+}
+
+func stableRandomFromSeed(seed string) (float64, error) {
+	seedValue, err := stringToSeed(seed)
+	if err != nil {
+		return 0, errors.Wrap(err, "generating seed")
+	}
+
+	return rand.New(rand.NewSource(seedValue)).Float64(), nil // #nosec G404 // Only used for generating a random number from static string, no need for cryptographic safety
+}
+
+func stringToSeed(s string) (int64, error) {
+	hash := md5.New() // #nosec G401 // Unly used to convert a string into a numer, no need for cryptographic safety
+	if _, err := fmt.Fprint(hash, s); err != nil {
+		return 0, errors.Wrap(err, "writing string to hasher")
+	}
+
+	var (
+		hashSum = hash.Sum(nil)
+		sum     int64
+	)
+
+	for i := 0; i < len(hashSum); i++ {
+		sum += int64(float64(hashSum[len(hashSum)-1-i]%10) * math.Pow(10, float64(i))) //nolint:gomnd // No need to put the 10 of 10**i into a constant named "ten"
+	}
+
+	return sum, nil
+}

plugins_core.go

@@ -16,6 +16,8 @@ import (
 	"github.com/Luzifer/twitch-bot/internal/actors/respond"
 	"github.com/Luzifer/twitch-bot/internal/actors/timeout"
 	"github.com/Luzifer/twitch-bot/internal/actors/whisper"
+	"github.com/Luzifer/twitch-bot/internal/template/numeric"
+	"github.com/Luzifer/twitch-bot/internal/template/random"
 	"github.com/Luzifer/twitch-bot/plugins"
 	"github.com/Luzifer/twitch-bot/twitch"
 	"github.com/pkg/errors"
@@ -23,7 +25,8 @@ import (
 )
 
 var (
-	coreActorRegistations = []plugins.RegisterFunc{
+	corePluginRegistrations = []plugins.RegisterFunc{
+		// Actors
 		ban.Register,
 		delay.Register,
 		deleteactor.Register,
@@ -35,13 +38,17 @@ var (
 		respond.Register,
 		timeout.Register,
 		whisper.Register,
+
+		// Template functions
+		numeric.Register,
+		random.Register,
 	}
 	knownModules []string
 )
 
 func initCorePlugins() error {
 	args := getRegistrationArguments()
-	for _, rf := range coreActorRegistations {
+	for _, rf := range corePluginRegistrations {
 		if err := rf(args); err != nil {
 			return errors.Wrap(err, "registering core plugin")
 		}

wiki/Home.md

@@ -140,35 +140,6 @@ rules: # See below for examples
 ...
 ```
 
-## Templating
-
-There are certain variables available in the strings with templating enabled:
-
-- `channel` - Channel the message was sent to, only available for regular messages not events
-- `msg` - The message object, used in functions, should not be sent to chat
-- `permitTimeout` - Value of `permit_timeout` in seconds
-- `username` - The username of the message author
-
-Additionally there are some functions available in the templates:
-
-- `arg <idx>` - Takes the message sent to the channel, splits by space and returns the Nth element
-- `botHasBadge <badge>` - Checks whether bot has the given badge in the current channel
-- `channelCounter <counter name>` - Wraps the counter name into a channel specific counter name including the channel name
-- `concat <delimiter> <...parts>` - Join the given string parts with delimiter
-- `counterValue <counter name>` - Returns the current value of the counter which identifier was supplied
-- `displayName <username> [fallback]` - Returns the display name the specified user set for themselves
-- `fixUsername <username>` - Ensures the username no longer contains the `@` or `#` prefix
-- `formatDuration <duration> <hours> <minutes> <seconds>` - Returns a formated duration. Pass empty strings to leave out the part: `{{ formatDuration .dur "hours" "minutes" "" }}` yields `N hours, M minutes`
-- `followDate <from> <to>` - Looks up when `from` followed `to`
-- `group <idx> [fallback]` - Gets matching group specified by index from `match_message` regular expression, when `fallback` is defined, it is used when group has an empty match
-- `lastQuoteIndex` - Gets the last quote index in the quote database for the current channel
-- `recentGame <username> [fallback]` - Returns the last played game name of the specified user (see shoutout example) or the `fallback` if the game could not be fetched. If no fallback was supplied the message will fail and not be sent.
-- `streamUptime <username>` - Returns the duration the stream is online (causes an error if no current stream is found)
-- `tag <tagname>` - Takes the message sent to the channel, returns the value of the tag specified
-- `toLower <string>` - Converts the given string to lower-case
-- `toUpper <string>` - Converts the given string to upper-case
-- `variable <name> [default]` - Returns the variable value or default in case it is empty
-
 ## Command executions
 
 Your command will get a JSON object passed through `stdin` you can parse to gain details about the message. It is expected to yield an array of actions on `stdout` and exit with status `0`. If it does not the action will be marked failed. In case you need to output debug output you can use `stderr` which is directly piped to the bots `stderr`.

wiki/Templating.md

@@ -0,0 +1,264 @@
+## Templating
+
+Generally speaking the templating uses [Golang `text/template`](https://pkg.go.dev/text/template) template syntax. All fields with templating enabled do support the full synax from the `text/template` package.
+
+### Variables
+
+There are certain variables available in the strings with templating enabled:
+
+- `channel` - Channel the message was sent to, only available for regular messages not events
+- `msg` - The message object, used in functions, should not be sent to chat
+- `permitTimeout` - Value of `permit_timeout` in seconds
+- `username` - The username of the message author
+
+
+### Functions
+
+Additionally to the built-in functions there are extra functions available in the templates:
+
+Examples below are using this syntax in the code block:
+
+```
+! Message matcher used for the input message
+> Input message if used in the example
+# Template used in the fields
+< Output from the template
+```
+
+#### `arg`
+
+Takes the message sent to the channel, splits by space and returns the Nth element
+
+Syntax: `arg <index>`
+
+Example:
+
+```
+> !bsg @tester
+# {{ arg 1 }} please refrain from BSG
+< @tester please refrain from BSG
+```
+
+#### `botHasBadge`
+
+Checks whether bot has the given badge in the current channel
+
+Syntax: `botHasBadge <badge>`
+
+Example:
+
+```
+# {{ botHasBadge "moderator" }}
+< true
+```
+
+#### `channelCounter`
+
+Wraps the counter name into a channel specific counter name including the channel name
+
+Syntax: `channelCounter <counter name>`
+
+Example:
+
+```
+# {{ channelCounter "test" }}
+< 5
+```
+
+#### `concat`
+
+Join the given string parts with delimiter
+
+Syntax: `concat <delimiter> <...parts>`
+
+Example:
+
+```
+# {{ concat ":" "test" .username }}
+< test:luziferus
+```
+
+#### `counterValue`
+
+Returns the current value of the counter which identifier was supplied
+
+Syntax: `counterValue <counter name>`
+
+Example:
+
+```
+# {{ counterValue (concat ":" .channel "test") }}
+< 5
+```
+
+#### `displayName`
+
+Returns the display name the specified user set for themselves
+
+Syntax: `displayName <username> [fallback]`
+
+Example:
+
+```
+# {{ displayName "luziferus" }} - {{ displayName "notexistinguser" "foobar" }}
+< Luziferus - foobar
+```
+
+#### `fixUsername`
+
+Ensures the username no longer contains the `@` or `#` prefix
+
+Syntax: `fixUsername <username>`
+
+Example:
+
+```
+# {{ fixUsername .channel }} - {{ fixUsername "@luziferus" }}
+< luziferus - luziferus
+```
+
+#### `formatDuration`
+
+Returns a formated duration. Pass empty strings to leave out the specific duration part.
+
+Syntax: `formatDuration <duration> <hours> <minutes> <seconds>`
+
+Example:
+
+```
+# {{ formatDuration (streamUptime .channel) "hours" "minutes" "seconds" }} - {{ formatDuration (streamUptime .channel) "hours" "minutes" "" }}
+< 5 hours, 33 minutes, 12 seconds - 5 hours, 33 minutes
+```
+
+#### `followDate`
+
+Looks up when `from` followed `to`
+
+Syntax: `followDate <from> <to>`
+
+Example:
+
+```
+# {{ followDate "tezrian" "luziferus" }}
+< 2021-04-10 16:07:07 +0000 UTC
+```
+
+#### `group`
+
+Gets matching group specified by index from `match_message` regular expression, when `fallback` is defined, it is used when group has an empty match
+
+Syntax: `group <idx> [fallback]`
+
+Example:
+
+```
+! !command ([0-9]+) ([a-z]+) ([a-z]*)
+> !command 12 test
+# {{ group 2 "oops" }} - {{ group 3 "oops" }}
+< test - oops
+```
+
+#### `lastQuoteIndex`
+
+Gets the last quote index in the quote database for the current channel
+
+Syntax: `lastQuoteIndex`
+
+Example:
+
+```
+# Last Quote: #{{ lastQuoteIndex }}
+< Last Quote: #32
+```
+
+#### `multiply`
+
+Returns float from calculation: `float1 * float2`
+
+Syntax: `multiply <float1> <float2>`
+
+Example:
+
+```
+# {{ printf "%.0f" (multiply 100 (seededRandom "test")) }}%
+< 35%
+```
+
+#### `recentGame`
+
+Returns the last played game name of the specified user (see shoutout example) or the `fallback` if the game could not be fetched. If no fallback was supplied the message will fail and not be sent.
+
+Syntax: `recentGame <username> [fallback]`
+
+Example:
+
+```
+# {{ recentGame "luziferus" "none" }} - {{ recentGame "thisuserdoesnotexist123" "none" }}
+< Metro Exodus - none
+```
+
+#### `streamUptime`
+
+Returns the duration the stream is online (causes an error if no current stream is found)
+
+Syntax: `streamUptime <username>`
+
+Example:
+
+```
+# {{ formatDuration (streamUptime "luziferus") "hours" "minutes" "" }}
+< 3 hours, 56 minutes
+```
+
+#### `seededRandom`
+
+Returns a float value stable for the given seed
+
+Syntax: `seededRandom <string-seed>`
+
+Example:
+
+```
+# Your int this hour: {{ printf "%.0f" (multiply (seededRandom (concat ":" "int" .username (now "2006-01-02 15"))) 100) }}%
+< Your int this hour: 17%
+```
+
+#### `tag`
+
+Takes the message sent to the channel, returns the value of the tag specified
+
+Syntax: `tag <tagname>`
+
+Example:
+
+```
+# {{ tag "login" }}
+< luziferus
+```
+
+#### `toLower` / `toUpper`
+
+Converts the given string to lower-case / upper-case
+
+Syntax: `toLower <string>` / `toUpper <string>`
+
+Example:
+
+```
+# {{ toLower "Test" }} - {{ toUpper "Test" }}
+< test - TEST
+```
+
+#### `variable`
+
+Returns the variable value or default in case it is empty
+
+Syntax: `variable <name> [default]`
+
+Example:
+
+```
+# {{ variable "foo" "fallback" }} - {{ variable "unsetvar" "fallback" }}
+< test - fallback
+```
+