add initial migration support (busted atm)

1 files changed, 199 insertions, 0 deletions

diff --git a/src/guff/database.cr b/src/guff/database.cr
index de11eb2..b21a26a 100644
--- a/src/guff/database.cr
+++ b/src/guff/database.cr
@@ -2,6 +2,205 @@ require "sqlite3"
 
 module Guff
   class Database < ::SQLite3::Database
+    SQL = {
+      table_exists: "
+        SELECT tbl_name
+
+          FROM sqlite_master
+
+         WHERE type = 'table'
+           AND tbl_name = ?
+      ",
+    }
+
     # TODO (add table_exists?)
+    def table_exists?(table_name : String)
+      one(SQL[:table_exists], [table_name]) == table_name
+    end
+
+    def one(
+      sql     : String
+    )
+      r = nil
+
+      bind(sql).execute do |rs|
+        if rs.next
+          # FIXME
+          r = rs[0]
+        end
+      end
+
+      # return result
+      r
+    end
+
+    def one(
+      sql     : String,
+      args    : Array(String)
+    )
+      r = nil
+
+      bind(sql, args).execute do |rs|
+        if rs.next
+          # FIXME
+          r = rs[0]
+        end
+      end
+
+      # return result
+      r
+    end
+
+    def one(
+      sql     : String,
+      args    : Hash(String, String),
+    )
+      r = nil
+
+      bind(sql, args).execute do |rs|
+        if rs.next
+          # FIXME
+          r = rs[0]
+        end
+      end
+
+      # return result
+      r
+    end
+
+    def row(sql : String)
+      r = nil
+
+      # exec query
+      bind(sql).execute do |rs|
+        if rs.next
+          r = to_row(rs)
+        end
+      end
+
+      # return result
+      r
+    end
+
+    def row(
+      sql   : String, 
+      args  : Array(String)
+    )
+      r = nil
+
+      # exec query
+      bind(sql, args).execute do |rs|
+        if rs.next
+          r = to_row(rs)
+        end
+      end
+
+      # return result
+      r
+    end
+
+    def row(
+      sql   : String, 
+      args  : Hash(String, String)
+    )
+      r = nil
+
+      # exec query
+      bind(sql, args).execute do |rs|
+        if rs.next
+          r = to_row(rs)
+        end
+      end
+
+      # return result
+      r
+    end
+
+    def all(
+      sql     : String,
+      args    : Array(String),
+      &block  : Proc(Hash(String, ::SQLite3::Value), Nil) \
+    )
+      # build statement
+      bind(sql, args).execute do |rs|
+        # walk results
+        while rs.next
+          # build row and pass it to callback
+          block.call(to_row(rs))
+        end
+      end
+
+      nil
+    end
+
+    def all(
+      sql     : String,
+      args    : Hash(String, String),
+      &block  : Proc(Hash(String, ::SQLite3::Value), Nil) \
+    )
+      bind(sql, args).execute do |rs|
+        # walk results
+        while rs.next
+          # build row and pass it to callback
+          block.call(to_row(rs))
+        end
+      end
+
+      # close statement, return nil
+      nil
+    end
+
+    def transaction(&block)
+      query("BEGIN")
+      block.call(self)
+      query("COMMIT")
+    end
+
+    private def bind(sql : String)
+      prepare(sql)
+    end
+
+    private def bind(
+      sql     : String,
+      args    : Array(String)?
+    )
+      # build statement
+      st = prepare(sql)
+
+      # build args
+      if args.size > 0
+        args.each_with_index do |val, i|
+          st[i + 1] = val
+        end
+      end
+
+      # return result
+      st
+    end
+
+    private def bind(
+      sql     : String,
+      args    : Hash(String, String)?
+    )
+      # build statement
+      if args.size > 0
+        st = prepare(sql)
+      end
+
+      # bind args
+      st[0] = args
+
+      # return result
+      st
+    end
+
+    private def to_row(rs : SQLite3::ResultSet) : Hash(String, ::SQLite3::Value)
+      0.upto(rs.column_count).inject(
+        {} of String => ::SQLite3::Value
+      ) do |r, i|
+        r[rs.columns[i]] = r[i]
+        r
+      end
+    end
   end
 end