(ns wanderung.cli

(:require [wanderung.core :as wc]

[clojure.set :refer [rename-keys]]

[environ.core :refer [env]])

(:import [clojure.lang IExceptionInfo]))

(defn- run-it! [f]

(try

f

(catch Throwable t

(println (.getMessage t))

(when-not (instance? IExceptionInfo t)

(.printStackTrace t))

(System/exit 1))

(finally

(shutdown-agents))))

(defn migrate [opts]

(let [merged-opts (-> (select-keys env [:wanderung-source :wanderung-target])

(rename-keys {:wanderung-source :source

:wanderung-target :target})

(merge opts))]

(println "Running with opts: " merged-opts)

(run-it! (wc/migration merged-opts))))

(def migration migrate)

(def m migrate)

(defn help

([]

(help {}))

([_]

(try

(println "WANDERUNG")

(println "---------")

(println "Run migrations with Datahike to and from various sources")

(println "USAGE:")

(println "clj -Twanderung [function] [function args]")

(println "FUNCTIONS:")

(println "---------")

(println "migrate/migration/m :source SOURCE :target TARGET")

(println "Description: Migrates from given source file to a target file. Source and target must be either file path or environment variable. Use WANDERUNG_SOURCE and WANDERUNG_TARGET environment variables if you don't want to use any input.")

(println "Example: clj -Twanderung migrate :source '\"./source-cfg.edn\"' :target '\"target-cfg.edn\"'")

(println "Example: clj -Twanderung m :source 'SOURCE_CFG' :target 'TARGET_CFG'")

(println "Example: WANDERUNG_SOURCE=./source-cfg.edn WANDERUNG_TARGET=./target-cfg.edn clj -Twanderung migrate'")

(println "---------")

(println "help/h")

(println "Description: Prints this lovely help.")

(println "Example: clj -Twanderung help")

(catch Throwable t

(println (.getMessage t))

(when-not (instance? IExceptionInfo t)

(.printStackTrace t))

(System/exit 1))

(finally

(shutdown-agents)))))

(def h help)

(defn migration [{:keys [source target check]}]

(let [read-cfg (fn [cfg] (when (some? cfg)

(if-let [path-from-env (some? (System/getenv cfg))]

path-from-env

(when (.exists (io/file cfg))

cfg))))]

(if-let [source (read-cfg source)]

(if-let [target (read-cfg target)]

(let [src-cfg (load-config source)

tgt-cfg (load-config target)

src-type (:wanderung/type src-cfg)

tgt-type (:wanderung/type tgt-cfg)]

(cond

(not (multimethod-for-dispatch-value? datoms-from-storage src-type))

(println "Cannot use" src-type "as source database.")

(not (multimethod-for-dispatch-value? datoms-to-storage tgt-type))

(println "Cannot use" tgt-type "as target database.")

(:wanderung/read-only? tgt-cfg)

(println "Cannot migrate to read-only database.")

:else (do

(println "➜ Start migrating from" src-type "to" tgt-type "...")

(migrate src-cfg tgt-cfg)

(println " ✓ Done")

(when check

(if (multimethod-for-dispatch-value? datoms-from-storage tgt-type)

(do

(println "➜ Comparing datoms between source and target...")

(if (datom/similar-datoms? (datoms-from-storage src-cfg)

(datoms-from-storage tgt-cfg))

(println " ✓ Success: Datoms look the same.")

(println "ERROR: The datoms differ between source and target.")))

(println "ERROR: The target does not support reading datoms"))))))

(println "ERORR: Invalid target configuration. Must be either file path or environment variable."))

(println "ERORR: Invalid source configuration. Must be either file path or environment variable."))))