-- =====================================================================
-- lib-core.input — Action-Mapping + Direction-Vector (v0.2.0)
-- See: meta/docs/superpowers/specs/2026-05-11-engine-input-symbolic-keys-design.md
--
-- v0.2.0 (P.2.6 2026-05-11): bind() accepts string-key-names only.
-- Integer engine.input.KEY_* args are rejected (modules go through
-- string-API; KEY_* stays as low-level engine-primitive).
--
-- Scope: action-mapping (string-key-name-arrays per action) +
-- direction-vector helper. DEPRECATED-MVP for: mouse-button actions,
-- gamepad bindings, action-context-stack, key-rebinding config,
-- modifier-combos, analog-axis, was_action_released edge.
-- =====================================================================

-- string → engine.input.KEY_* mapping. Lowercase-only convention.
-- Right-modifier-Aliases (rshift/rctrl/ralt) + function-keys + special-keys
-- (delete/insert/home/end/pageup/pagedown) sind forthcoming, additiv wenn
-- engine.input rechte-Modifier + F-keys + Special-Keys exposed.
local KEY_MAP = {
    -- Letters (26)
    a = engine.input.KEY_A,  b = engine.input.KEY_B,  c = engine.input.KEY_C,
    d = engine.input.KEY_D,  e = engine.input.KEY_E,  f = engine.input.KEY_F,
    g = engine.input.KEY_G,  h = engine.input.KEY_H,  i = engine.input.KEY_I,
    j = engine.input.KEY_J,  k = engine.input.KEY_K,  l = engine.input.KEY_L,
    m = engine.input.KEY_M,  n = engine.input.KEY_N,  o = engine.input.KEY_O,
    p = engine.input.KEY_P,  q = engine.input.KEY_Q,  r = engine.input.KEY_R,
    s = engine.input.KEY_S,  t = engine.input.KEY_T,  u = engine.input.KEY_U,
    v = engine.input.KEY_V,  w = engine.input.KEY_W,  x = engine.input.KEY_X,
    y = engine.input.KEY_Y,  z = engine.input.KEY_Z,
    -- Numbers (10)
    ["0"] = engine.input.KEY_ZERO,  ["1"] = engine.input.KEY_ONE,
    ["2"] = engine.input.KEY_TWO,   ["3"] = engine.input.KEY_THREE,
    ["4"] = engine.input.KEY_FOUR,  ["5"] = engine.input.KEY_FIVE,
    ["6"] = engine.input.KEY_SIX,   ["7"] = engine.input.KEY_SEVEN,
    ["8"] = engine.input.KEY_EIGHT, ["9"] = engine.input.KEY_NINE,
    -- Arrows (4)
    left  = engine.input.KEY_LEFT,  right = engine.input.KEY_RIGHT,
    up    = engine.input.KEY_UP,    down  = engine.input.KEY_DOWN,
    -- Whitespace + control (5)
    space     = engine.input.KEY_SPACE,
    tab       = engine.input.KEY_TAB,
    enter     = engine.input.KEY_ENTER,
    backspace = engine.input.KEY_BACKSPACE,
    escape    = engine.input.KEY_ESCAPE,
    -- Modifiers (left-side; aliases for ergonomics)
    shift  = engine.input.KEY_LEFT_SHIFT,    lshift = engine.input.KEY_LEFT_SHIFT,
    ctrl   = engine.input.KEY_LEFT_CONTROL,  lctrl  = engine.input.KEY_LEFT_CONTROL,
    alt    = engine.input.KEY_LEFT_ALT,      lalt   = engine.input.KEY_LEFT_ALT,
    -- Console-toggle (DE: ^, US: `)
    ["^"]  = engine.input.KEY_GRAVE,
}

local bindings = {}  -- action_name -> array of key-codes (post-resolution)

local M = {}

function M.bind(action_name, keys)
    if type(action_name) ~= "string" then
        error("input.bind: action_name must be a string")
    end
    if type(keys) ~= "table" or #keys == 0 then
        error(string.format("input.bind: keys must be a non-empty array of key-name strings (action '%s')",
            action_name))
    end
    -- Resolve each string-key to engine keycode via KEY_MAP. Atomic: if any
    -- key invalid, the entire bind fails without partial-state mutation.
    local resolved = {}
    for i, k in ipairs(keys) do
        if type(k) ~= "string" then
            error(string.format("input.bind: key #%d for action '%s' must be a lowercase string (got %s); use 'a'..'z', '0'..'9', 'left', 'space', 'ctrl', 'escape', etc. — see lib-core.input README for full table",
                i, action_name, type(k)))
        end
        local code = KEY_MAP[k]
        if code == nil then
            error(string.format("input.bind: unknown key-name '%s' for action '%s' — must be lowercase, see KEY_MAP in lib-core.input/init.lua for valid keys",
                k, action_name))
        end
        resolved[i] = code
    end
    bindings[action_name] = resolved
end

function M.unbind(action_name)
    bindings[action_name] = nil
end

function M.is_action_down(action_name)
    local keys = bindings[action_name]
    if not keys then return false end
    for _, k in ipairs(keys) do
        if engine.input.is_key_down(k) then return true end
    end
    return false
end

function M.was_action_pressed(action_name)
    local keys = bindings[action_name]
    if not keys then return false end
    for _, k in ipairs(keys) do
        if engine.input.was_pressed(k) then return true end
    end
    return false
end

-- Direction-vector helper: returns {x, y} in {-1, 0, +1} each axis.
-- Y-down-positive per Sporel pixel-convention (ADR-0031).
function M.direction(left_action, right_action, up_action, down_action)
    local x = (M.is_action_down(right_action) and 1 or 0)
            - (M.is_action_down(left_action)  and 1 or 0)
    local y = (M.is_action_down(down_action)  and 1 or 0)
            - (M.is_action_down(up_action)    and 1 or 0)
    return { x = x, y = y }
end

function M.action_count()
    local n = 0
    for _ in pairs(bindings) do n = n + 1 end
    return n
end

-- DEPRECATED-MVP: bind_mouse(action, button)         -- mouse-button slice
-- DEPRECATED-MVP: bind_gamepad(action, ...)           -- gamepad slice
-- DEPRECATED-MVP: push_context(name) / pop_context()  -- action-context-stack
-- DEPRECATED-MVP: load_bindings_from_config(path)     -- key-rebinding slice
-- DEPRECATED-MVP: was_action_released(action)         -- lift-detection slice
-- DEPRECATED-MVP: right-modifier-keys (rshift/rctrl/ralt)  -- engine.input.KEY_RIGHT_* erforderlich
-- DEPRECATED-MVP: function-keys (f1..f12) + special-keys (delete/insert/home/end/pageup/pagedown) -- engine.input-Erweiterung erforderlich

return M