;;; Commentary:
;;; TODO

;;; Code:

(require 'emacsql)
(require 'emacsql-psql)
(require 'dash)
(require 's)
(require 'cl-lib)

;;; Config

(defvar-local company-sql-db-host "localhost"
  "Host of the postgresql database to query for autocomplete information")

(defvar-local company-sql-db-port 5432
  "Port of the postgresql database to query for autocomplete information")

(defvar-local company-sql-db-user "postgres"
  "Username of the postgresql database to query for autocomplete information")

(defvar-local company-sql-db-name nil
  "PostgreSQL database name to query for autocomplete information")

;;; DB Connection

(defvar-local company-sql/connection nil)

(defun company-sql/connect ()
  (unless company-sql/connection
    (setq-local company-sql/connection
                (emacsql-psql company-sql-db-name
                              :hostname company-sql-db-host
                              :username company-sql-db-user
                              :port (number-to-string company-sql-db-port))))
  company-sql/connection)

;;; Utils

(defmacro comment (&rest _))

(defun ->string (x)
  (cond
   ((stringp x) x)
   ((symbolp x) (symbol-name x))))

(defun alist-get-equal (key alist)
  "Like `alist-get', but uses `equal' instead of `eq' for comparing keys"
  (->> alist
       (-find (lambda (pair) (equal key (car pair))))
       (cdr)))

;;; Listing relations

(cl-defun company-sql/list-tables (conn)
  (with-timeout (3)
    (-map (-compose 'symbol-name 'car)
          (emacsql conn
                   [:select [tablename]
                            :from pg_catalog:pg_tables
                            :where (and (!= schemaname '"information_schema")
                                        (!= schemaname '"pg_catalog"))]))))

(cl-defun company-sql/list-columns (conn)
  (with-timeout (3)
    (-map
     (lambda (row)
       (propertize (symbol-name (nth 0 row))
                   'table-name (nth 1 row)
                   'data-type  (nth 2 row)))
     (emacsql conn
              [:select [column_name
                        table_name
                        data_type]
                       :from information_schema:columns]))))

;;; Keywords

(defvar company-postgresql/keywords
  (list
"a" "abort" "abs" "absent" "absolute" "access" "according" "action" "ada" "add"
"admin" "after" "aggregate" "all" "allocate" "also" "alter" "always" "analyse"
"analyze" "and" "any" "are" "array" "array_agg" "array_max_cardinality" "as"
"asc" "asensitive" "assertion" "assignment" "asymmetric" "at" "atomic" "attach"
"attribute" "attributes" "authorization" "avg" "backward" "base64" "before"
"begin" "begin_frame" "begin_partition" "bernoulli" "between" "bigint" "binary"
"bit" "bit_length" "blob" "blocked" "bom" "boolean" "both" "breadth" "by" "c"
"cache" "call" "called" "cardinality" "cascade" "cascaded" "case" "cast"
"catalog" "catalog_name" "ceil" "ceiling" "chain" "char" "character"
"characteristics" "characters" "character_length" "character_set_catalog"
"character_set_name" "character_set_schema" "char_length" "check" "checkpoint"
"class" "class_origin" "clob" "close" "cluster" "coalesce" "cobol" "collate"
"collation" "collation_catalog" "collation_name" "collation_schema" "collect"
"column" "columns" "column_name" "command_function" "command_function_code"
"comment" "comments" "commit" "committed" "concurrently" "condition"
"condition_number" "configuration" "conflict" "connect" "connection"
"connection_name" "constraint" "constraints" "constraint_catalog"
"constraint_name" "constraint_schema" "constructor" "contains" "content"
"continue" "control" "conversion" "convert" "copy" "corr" "corresponding" "cost"
"count" "covar_pop" "covar_samp" "create" "cross" "csv" "cube" "cume_dist"
"current" "current_catalog" "current_date" "current_default_transform_group"
"current_path" "current_role" "current_row" "current_schema" "current_time"
"current_timestamp" "current_transform_group_for_type" "current_user" "cursor"
"cursor_name" "cycle" "data" "database" "datalink" "date"
"datetime_interval_code" "datetime_interval_precision" "day" "db" "deallocate"
"dec" "decimal" "declare" "default" "defaults" "deferrable" "deferred" "defined"
"definer" "degree" "delete" "delimiter" "delimiters" "dense_rank" "depends"
"depth" "deref" "derived" "desc" "describe" "descriptor" "detach"
"deterministic" "diagnostics" "dictionary" "disable" "discard" "disconnect"
"dispatch" "distinct" "dlnewcopy" "dlpreviouscopy" "dlurlcomplete"
"dlurlcompleteonly" "dlurlcompletewrite" "dlurlpath" "dlurlpathonly"
"dlurlpathwrite" "dlurlscheme" "dlurlserver" "dlvalue" "do" "document" "domain"
"double" "drop" "dynamic" "dynamic_function" "dynamic_function_code" "each"
"element" "else" "empty" "enable" "encoding" "encrypted" "end" "end-exec"
"end_frame" "end_partition" "enforced" "enum" "equals" "escape" "event" "every"
"except" "exception" "exclude" "excluding" "exclusive" "exec" "execute" "exists"
"exp" "explain" "expression" "extension" "external" "extract" "false" "family"
"fetch" "file" "filter" "final" "first" "first_value" "flag" "float" "floor"
"following" "for" "force" "foreign" "fortran" "forward" "found" "frame_row"
"free" "freeze" "from" "fs" "full" "function" "functions" "fusion" "g" "general"
"generated" "get" "global" "go" "goto" "grant" "granted" "greatest" "group"
"grouping" "groups" "handler" "having" "header" "hex" "hierarchy" "hold" "hour"
"id" "identity" "if" "ignore" "ilike" "immediate" "immediately" "immutable"
"implementation" "implicit" "import" "in" "include" "including" "increment"
"indent" "index" "indexes" "indicator" "inherit" "inherits" "initially" "inline"
"inner" "inout" "input" "insensitive" "insert" "instance" "instantiable"
"instead" "int" "integer" "integrity" "intersect" "intersection" "interval"
"into" "invoker" "is" "isnull" "isolation" "join" "k" "key" "key_member"
"key_type" "label" "lag" "language" "large" "last" "last_value" "lateral" "lead"
"leading" "leakproof" "least" "left" "length" "level" "library" "like"
"like_regex" "limit" "link" "listen" "ln" "load" "local" "localtime"
"localtimestamp" "location" "locator" "lock" "locked" "logged" "lower" "m" "map"
"mapping" "match" "matched" "materialized" "max" "maxvalue" "max_cardinality"
"member" "merge" "message_length" "message_octet_length" "message_text" "method"
"min" "minute" "minvalue" "mod" "mode" "modifies" "module" "month" "more" "move"
"multiset" "mumps" "name" "names" "namespace" "national" "natural" "nchar"
"nclob" "nesting" "new" "next" "nfc" "nfd" "nfkc" "nfkd" "nil" "no" "none"
"normalize" "normalized" "not" "nothing" "notify" "notnull" "nowait" "nth_value"
"ntile" "null" "nullable" "nullif" "nulls" "number" "numeric" "object"
"occurrences_regex" "octets" "octet_length" "of" "off" "offset" "oids" "old"
"on" "only" "open" "operator" "option" "options" "or" "order" "ordering"
"ordinality" "others" "out" "outer" "output" "over" "overlaps" "overlay"
"overriding" "owned" "owner" "p" "pad" "parallel" "parameter" "parameter_mode"
"parameter_name" "parameter_ordinal_position" "parameter_specific_catalog"
"parameter_specific_name" "parameter_specific_schema" "parser" "partial"
"partition" "pascal" "passing" "passthrough" "password" "path" "percent"
"percentile_cont" "percentile_disc" "percent_rank" "period" "permission"
"placing" "plans" "pli" "policy" "portion" "position" "position_regex" "power"
"precedes" "preceding" "precision" "prepare" "prepared" "preserve" "primary"
"prior" "privileges" "procedural" "procedure" "procedures" "program" "public"
"publication" "quote" "range" "rank" "read" "reads" "real" "reassign" "recheck"
"recovery" "recursive" "ref" "references" "referencing" "refresh" "regr_avgx"
"regr_avgy" "regr_count" "regr_intercept" "regr_r2" "regr_slope" "regr_sxx"
"regr_sxy" "regr_syy" "reindex" "relative" "release" "rename" "repeatable"
"replace" "replica" "requiring" "reset" "respect" "restart" "restore" "restrict"
"result" "return" "returned_cardinality" "returned_length"
"returned_octet_length" "returned_sqlstate" "returning" "returns" "revoke"
"right" "role" "rollback" "rollup" "routine" "routines" "routine_catalog"
"routine_name" "routine_schema" "row" "rows" "row_count" "row_number" "rule"
"savepoint" "scale" "schema" "schemas" "schema_name" "scope" "scope_catalog"
"scope_name" "scope_schema" "scroll" "search" "second" "section" "security"
"select" "selective" "self" "sensitive" "sequence" "sequences" "serializable"
"server" "server_name" "session" "session_user" "set" "setof" "sets" "share"
"show" "similar" "simple" "size" "skip" "smallint" "snapshot" "some" "source"
"space" "specific" "specifictype" "specific_name" "sql" "sqlcode" "sqlerror"
"sqlexception" "sqlstate" "sqlwarning" "sqrt" "stable" "standalone" "start"
"state" "statement" "static" "statistics" "stddev_pop" "stddev_samp" "stdin"
"stdout" "storage" "strict" "strip" "structure" "style" "subclass_origin"
"submultiset" "subscription" "substring" "substring_regex" "succeeds" "sum"
"symmetric" "sysid" "system" "system_time" "system_user" "t" "table" "tables"
"tablesample" "tablespace" "table_name" "temp" "template" "temporary" "text"
"then" "ties" "time" "timestamp" "timezone_hour" "timezone_minute" "to" "token"
"top_level_count" "trailing" "transaction" "transactions_committed"
"transactions_rolled_back" "transaction_active" "transform" "transforms"
"translate" "translate_regex" "translation" "treat" "trigger" "trigger_catalog"
"trigger_name" "trigger_schema" "trim" "trim_array" "true" "truncate" "trusted"
"type" "types" "uescape" "unbounded" "uncommitted" "under" "unencrypted" "union"
"unique" "unknown" "unlink" "unlisten" "unlogged" "unnamed" "unnest" "until"
"untyped" "update" "upper" "uri" "usage" "user" "user_defined_type_catalog"
"user_defined_type_code" "user_defined_type_name" "user_defined_type_schema"
"using" "vacuum" "valid" "validate" "validator" "value" "values" "value_of"
"varbinary" "varchar" "variadic" "varying" "var_pop" "var_samp" "verbose"
"version" "versioning" "view" "views" "volatile" "when" "whenever" "where"
"whitespace" "width_bucket" "window" "with" "within" "without" "work" "wrapper"
"write" "xml" "xmlagg" "xmlattributes" "xmlbinary" "xmlcast" "xmlcomment"
"xmlconcat" "xmldeclaration" "xmldocument" "xmlelement" "xmlexists" "xmlforest"
"xmliterate" "xmlnamespaces" "xmlparse" "xmlpi" "xmlquery" "xmlroot" "xmlschema"
"xmlserialize" "xmltable" "xmltext" "xmlvalidate" "year" "yes" "zone"))

;;; Company backend

(cl-defun company-postgresql/candidates (prefix conn)
  (-filter
   (apply-partially #'s-starts-with? prefix)
   (append (-map (lambda (s)
                   (propertize s 'company-postgresql-annotation "table"))

           (-map (lambda (s)
                   (propertize s 'company-postgresql-annotation
                               (format "%s.%s %s"
                                       (get-text-property 0 'table-name s)
                                       s
                                       (->
                                        (get-text-property 0 'data-type s)
                                        (->string)
                                        (upcase)))))
                 (company-sql/list-columns conn))
           (-map (lambda (s)
                   (propertize s 'company-postgresql-annotation "keyword"))
                 company-postgresql/keywords)))))

(defun company-postgresql (command &optional arg &rest _)
  (interactive (list 'interactive))
  (cl-case command
    (interactive (company-begin-backend 'company-postgresql))
    (init (company-sql/connect))
    (prefix (company-grab-symbol))
    (annotation
     (get-text-property 0 'company-postgresql-annotation arg))
    (candidates (company-postgresql/candidates
                 arg
                 (company-sql/connect)))
    (duplicates t)
    (ignore-case t)))

;;; org-babel company sql

(defvar-local org-company-sql/connections
  ())

(defun org-company-sql/connect (conn-params)
  (or (alist-get-equal conn-params org-company-sql/connections)
      (let ((conn (apply 'emacsql-psql conn-params)))
        (add-to-list 'org-company-sql/connections (cons conn-params conn))
        conn)))

(defun org-company-sql/in-sql-source-block-p ()
  (let ((org-elt (org-element-at-point)))
    (and (eq 'src-block (car org-elt))
         (equal "sql" (plist-get (cadr org-elt)
                                 :language)))))

(defun org-company-sql/parse-cmdline (cmdline)
  (let* ((lexed (s-split (rx (one-or-more blank)) cmdline))
         (go (lambda (state tokens)
               (if (null tokens) ()
                 (let ((token (car tokens))
                       (tokens (cdr tokens)))
                   (if (null state)
                       (if (s-starts-with? "-" token)
                           (funcall go token tokens)
                         (cons token (funcall go state tokens)))
                     (cons (cons state token)  ; ("-h" . "localhost")
                           (funcall go nil tokens)))))))
         (opts (funcall go nil lexed)))
    opts))

(defun org-company-sql/source-block-conn-params ()
  (let* ((block-info (org-babel-get-src-block-info))
         (params (caddr block-info))
         (cmdline (alist-get :cmdline params))
         (parsed (org-company-sql/parse-cmdline cmdline))
         (opts (-filter #'listp parsed))
         (positional (-filter #'stringp parsed))
         (host (alist-get-equal "-h" opts))
         (port (or (alist-get-equal "-p" opts)
                   "5432"))
         (dbname (or (alist-get-equal "-d" opts)
                     (car positional)))
         (username (or (alist-get-equal "-U" opts)
                       (cadr positional))))
    (list dbname
          :hostname host
          :username username
          :port port)))

(defun org-company-sql/connection-for-source-block ()
  (org-company-sql/connect
   (org-company-sql/source-block-conn-params)))


(defun company-ob-postgresql (command &optional arg &rest _)
  (interactive (list 'interactive))
  (cl-case command
    (interactive (company-begin-backend 'company-ob-postgresql))
    (prefix (and (org-company-sql/in-sql-source-block-p)
                 (company-grab-symbol)))
    (annotation (get-text-property 0 'company-postgresql-annotation arg))
    (candidates
     (company-postgresql/candidates
      arg
      (org-company-sql/connection-for-source-block)))
    (duplicates t)
    (ignore-case t)))

;;;

(provide 'company-sql)