local _ENV = mkmodule('plugins.blueprint')

local argparse = require('argparse')
local utils = require('utils')

local valid_phase_list = {
    'dig',
    'carve',
    'construct',
    'build',
    'place',
    'zone',
    'query',
    'rooms',
}
valid_phases = utils.invert(valid_phase_list)

local meta_phase_list = {
    'build',
    'place',
    'zone',
    'query',
}
meta_phases = utils.invert(meta_phase_list)

local valid_formats_list = {
    'minimal',
    'pretty',
}
valid_formats = utils.invert(valid_formats_list)

local valid_split_strategies_list = {
    'none',
    'phase',
}
valid_split_strategies = utils.invert(valid_split_strategies_list)

local function parse_cursor(opts, arg)
    local cursor = argparse.coords(arg)
    -- be careful not to replace struct members when called from C++, but also
    -- create the table as needed when called from lua
    if not opts.start then opts.start = {} end
    utils.assign(opts.start, cursor)
end

local function parse_enum(opts, valid, name, val)
    if not valid[val] then
        qerror(('unknown %s: "%s"; expected one of: %s')
               :format(name, val, table.concat(valid, ', ')))
    end
    opts[name] = val
end

local function parse_format(opts, file_format)
    parse_enum(opts, valid_formats, 'format', file_format)
end

local function is_int(val)
    return val and val == math.floor(val)
end

local function is_positive_int(val)
    return is_int(val) and val > 0
end

local function parse_start(opts, args)
    local arg_list = argparse.stringList(args)
    local x_str, y_str = table.remove(arg_list, 1), table.remove(arg_list, 1)
    local x, y = tonumber(x_str), tonumber(y_str)
    if not is_positive_int(x) or not is_positive_int(y) then
        qerror(('playback start offsets must be positive integers: "%s", "%s"')
               :format(x_str or '', y_str or ''))
    end

    if not opts.playback_start then opts.playback_start = {} end
    opts.playback_start.x, opts.playback_start.y = x, y
    if #arg_list > 0 then
        opts.playback_start_comment = table.concat(arg_list, ', ')
    end
end

local function parse_split_strategy(opts, strategy)
    parse_enum(opts, valid_split_strategies, 'split_strategy', strategy)
end

local function parse_positionals(opts, args, start_argidx)
    local argidx = start_argidx or 1

    -- set defaults
    opts.name, opts.auto_phase = 'blueprint', true

    local name = args[argidx]
    if not name then return end
    if name == '' then
        qerror(('invalid basename: "%s"; must be a valid, non-empty pathname')
               :format(args[argidx]))
    end
    argidx = argidx + 1
    -- normalize paths and remove leading slashes
    opts.name = utils.normalizePath(name):gsub('^/', '')

    local auto_phase = true
    local phase = args[argidx]
    while phase do
        if not valid_phases[phase] then
            qerror(('unknown phase: "%s"; expected one of: %s')
                   :format(phase, table.concat(valid_phase_list, ', ')))
        end
        auto_phase = false
        opts[phase] = true
        argidx = argidx + 1
        phase = args[argidx]
    end
    opts.auto_phase = auto_phase
end

local function process_args(opts, args)
    if args[1] == 'help' then
        opts.help = true
        return
    end

    -- set defaults
    opts.format = valid_formats_list[1]
    opts.split_strategy = valid_split_strategies_list[1]

    local positionals = argparse.processArgsGetopt(args, {
            {'c', 'cursor', hasArg=true,
             handler=function(optarg) parse_cursor(opts, optarg) end},
            {'e', 'engrave', handler=function() opts.engrave = true end},
            {'f', 'format', hasArg=true,
             handler=function(optarg) parse_format(opts, optarg) end},
            {'h', 'help', handler=function() opts.help = true end},
            {nil, 'nometa', handler=function() opts.nometa = true end},
            {'s', 'playback-start', hasArg=true,
             handler=function(optarg) parse_start(opts, optarg) end},
            {nil, 'smooth', handler=function() opts.smooth = true end},
            {'t', 'splitby', hasArg=true,
             handler=function(optarg) parse_split_strategy(opts, optarg) end},
        })

    if opts.help then
        return
    end

    return positionals
end

-- used by the gui/blueprint script
function parse_gui_commandline(opts, args)
    local positionals = process_args(opts, args)
    if opts.help then return end
    parse_positionals(opts, positionals)
end

-- dimension must be a non-nil integer that is >= 1 (or at least non-zero if
-- negative_ok is true)
local function is_bad_dim(dim, negative_ok)
    return not is_int(dim) or
            (not negative_ok and dim < 1 or dim == 0)
end

function parse_commandline(opts, ...)
    local positionals = process_args(opts, {...})
    if opts.help then return end

    local width, height = tonumber(positionals[1]), tonumber(positionals[2])
    if is_bad_dim(width) or is_bad_dim(height) then
        qerror(('invalid width or height: "%s" "%s"; width and height must' ..
                ' be positive integers'):format(positionals[1], positionals[2]))
    end
    opts.width, opts.height, opts.depth = width, height, 1

    local depth = tonumber(positionals[3])
    if depth then
        if is_bad_dim(depth, true) then
            qerror(('invalid depth: "%s"; must be a non-zero integer')
                   :format(positionals[3]))
        end
        opts.depth = depth
    end

    if opts.playback_start and opts.playback_start.x > 0 then
        if opts.playback_start.x > width then
            qerror(('playback start x offset outside width of blueprint: %d')
                   :format(opts.playback_start.x))
        end
        if opts.playback_start.y > height then
            qerror(('playback start y offset outside height of blueprint: %d')
                   :format(opts.playback_start.y))
        end
    end

    parse_positionals(opts, positionals, depth and 4 or 3)
end

function is_meta_phase(opts, phase)
    -- this is called directly by cpp so ensure we return a boolean, not nil
    return not opts.nometa and meta_phases[phase] or false
end

-- returns the name of the output file for the given context
function get_filename(opts, phase)
    local fullname = 'blueprints/' .. opts.name
    local _,_,basename = fullname:find('/([^/]+)/?$')
    if not basename then
        -- should not happen since opts.name should already be validated
        error(('could not parse basename out of "%s"'):format(fullname))
    end
    if fullname:endswith('/') then
        fullname = fullname .. basename
    end
    if opts.split_strategy == 'phase' then
        if is_meta_phase(opts, phase) then
            phase = 'meta'
        end
        return ('%s-%s.csv'):format(fullname, phase)
    end
    -- no splitting
    return ('%s.csv'):format(fullname)
end

-- compatibility with old exported API.
local function do_phase(start_pos, end_pos, name, phase)
    local width = math.abs(start_pos.x - end_pos.x) + 1
    local height = math.abs(start_pos.y - end_pos.y) + 1
    local depth = math.abs(start_pos.z - end_pos.z) + 1
    if start_pos.z > end_pos.z then depth = -depth end

    local x = math.min(start_pos.x, end_pos.x)
    local y = math.min(start_pos.y, end_pos.y)
    local z = start_pos.z

    local cursor = ('--cursor=%d,%d,%d'):format(x, y, z)

    run(tostring(width), tostring(height), tostring(depth), tostring(name),
        phase, cursor)
end
for phase in pairs(valid_phases) do
    _ENV[phase] = function(s, e, n) do_phase(s, e, n, phase) end
end

return _ENV