module Hccb
    exposing
        ( barcode
        , standardSpec
        )

{-| A High Capacity Color Barcode (HCCB) generator

# Usage
@docs barcode

# Specification
@docs standardSpec
-}

import Html exposing (Html)
import Svg exposing (Svg)


-- Project Imports

import Hccb.Graphic exposing (graphicResize)
import Hccb.Barcode exposing (..)
import Hccb.Specification exposing (Specification)
import Hccb.SpecDim exposing (barcodeDim)
import Hccb.ColorData exposing (ColorData, dataToColors, colorsPrefix)
import Hccb.Bits exposing (Bits(..))
import Hccb.Pad exposing (Pad, zeroPad, equalPad)
import Hccb.Dim exposing (Dim(..))
import Hccb.Rect exposing (Rect(..), pointOf)
import Hccb.Point exposing (Point(..))


type alias Data =
    List Int


{-| The "standard" specification for an HCCB barcode. Note that you can quite
    easily change the size--it should be readable. If you change the padding,
    strip height, insets, or dimensions, however, it may not be readable.
-}
standardSpec : Specification
standardSpec =
    { bits = ThreeBits
    , size =
        { rows = 12
        , cols = 24
        }
    , whiteFramePad = equalPad 20.87
    , blackBackgroundPad = equalPad 8.94
    , whiteStripHeight = 5.96
    , rowInset = 5.96
    , triangleDim = Dim 25.48 20.87
    }


{-| Generate an HCCB (High Capacity Color Barcode) SVG in HTML

# Example use
`barcode standardSpec 100 100 [1, 2, 3, 4]`
-}
barcode : Specification -> Float -> Float -> Data -> Html msg
barcode spec w_ h_ data =
    let
        dim =
            barcodeDim spec

        {- Subtract padding from a rectangle -}
        minusPad : Pad -> Rect -> Rect
        minusPad pad (Rect (Point x y) (Dim w h)) =
            Rect (Point (x + pad.left) (y + pad.top))
                (Dim (w - pad.left - pad.right) (h - pad.top - pad.bottom))

        generate : Rect -> List (Svg msg)
        generate outerRect =
            let
                innerRect =
                    outerRect |> minusPad spec.whiteFramePad

                innerPaddedRect =
                    innerRect |> minusPad spec.blackBackgroundPad

                rowSpec =
                    getRowSpec spec

                coloredData =
                    (colorsPrefix spec.bits) ++ (dataToColors ThreeBits data)
            in
                []
                    ++ (drawFrame outerRect innerRect)
                    ++ (drawTriangles spec (pointOf innerPaddedRect) coloredData)
                    ++ (drawStrips rowSpec (pointOf innerPaddedRect) spec.size)
    in
        graphicResize dim (Dim w_ h_) zeroPad generate