# This file is a part of JuliaFEM.
# License is MIT: see https://github.com/JuliaFEM/JuliaFEM.jl/blob/master/LICENSE.md

global handlers = Dict()

"""
Register new handler for parser
"""
function add_handler(section, function_name)
  handlers[section] = function_name
end

function create_or_get(model, key)
    if !(key in keys(model))
        model[key] = Dict()
    end
    return model[key]
end

function parse_header(header_line)
    args = map(s -> strip(s), split(header_line, ","))
    args[1] = strip(args[1], '*')
    d = Dict("section" => args[1], "options" => Dict())
    options = d["options"]
    for k in args[2:end]
        args2 = split(k, "=")
        options[args2[1]] = args2[2]
    end
    return d
end

function parse_node_section(model, header, data)
    nodes = create_or_get(model, "nodes")
    for line in split(data, "\n")
        m = matchall(r"[-0-9.]+", line)
        id = parse(Int, m[1])
        coords = float(m[2:end])
        nodes[id] = coords
    end
end

function parse_element_section(model, header, data)
    info("Parsing elements")
    eldims = Dict(
        "C3D10" => 10,
        "C3D4" => 4,
        "S3" => 3,
        "STRI65" => 6)
    eltype = header["options"]["TYPE"]
    if !(eltype in keys(eldims))
        throw("Element $eltype dimension information missing")
    end
    eldim = eldims[eltype]
    test_match = matchall(r"[0-9]+", "234, 242")
    m = matchall(r"[0-9]+", data)   
    m = map((s) -> parse(Int, s), m)
    elements = create_or_get(model, "elements")
    m = reshape(m, eldim+1, round(Int, length(m)/(eldim+1)))
    nel = size(m)[2]
    info("$nel elements found")
    for i=1:nel
        elements[m[1,i]] = m[2:end,i]
    end
    if "ELSET" in keys(header["options"])
        elsets = create_or_get(model, "elsets")
        elset_name = header["options"]["ELSET"]
        info("Creating ELSET $elset_name")
        elsets[elset_name] = Int64[]
        for i=1:nel
            push!(elsets[elset_name], m[1,i])
        end
    end
end

function parse_elset_section(model, header, data)
    elset_name = header["options"]["ELSET"]
    info("Creating element set $elset_name")
    m = matchall(r"[0-9]+", data)
    element_ids = map((s) -> parse(Int, s), m)
    elsets = create_or_get(model, "elsets")
    elsets[elset_name] = Int64[]
    for j in element_ids
        push!(elsets[elset_name], j)
    end
end

function parse_nodeset_section(model, header, data)
    nset_name = header["options"]["NSET"]
    info("Creating node set $nset_name")
    m = matchall(r"[0-9]+", data)
    node_ids = map((s) -> parse(Int, s), m)
    nsets = create_or_get(model, "nsets")
    nsets[nset_name] = Int64[]
    for j in node_ids
        push!(nsets[nset_name], j)
    end
end

function parse_abaqus(fid::IOStream)
    model = Dict()
    section = nothing
    header = nothing
    data = ASCIIString[]
    info("Registered handlers: $(keys(handlers))")

    function process_section(section)
        if section == nothing
            return
        end
        if !(section in keys(handlers))
            info("Don't know what to do with data in section $section")
            info("Skipping $(length(data)) bytes of unknown data")
            return
        end
        joined = join(data, "")
        handlers[section](model, header, strip(joined))
        empty!(data)
    end

    line_idx = 0
    for line in eachline(fid)
        if startswith(line, "**")
            continue
        end
        if startswith(line, "*")
            process_section(section)
            header = parse_header(line)
            section = header["section"]
            continue
        end
        push!(data, line)
    end 
    process_section(section)
    return model
end

# add handlers
add_handler("NODE", parse_node_section)
add_handler("ELEMENT", parse_element_section)
add_handler("NSET", parse_nodeset_section)
add_handler("ELSET", parse_elset_section)