-- =====================================================================
-- lib-core.input — Action-Mapping + Direction-Vector (v0.4.0)
-- See: meta/docs/superpowers/specs/2026-05-12-p3-3-mouse-input-design.md
--
-- v0.4.0 (P.3.10 2026-05-15): was_action_released added — release-edge
-- detection parallel to was_action_pressed. Engine-Surface:
-- engine.input.was_released + was_mouse_released. Selection-Lib's
-- prev_click_down workaround promoted.
--
-- v0.3.0 (P.3.3 2026-05-12): bind() now accepts unified key+mouse
-- strings via BIND_MAP with kind-tagged entries ({kind="key"|"mouse",
-- code=<engine-int>}). Mixed bindings supported: e.g.
--   input.bind("interact", {"e", "mouse_left"})
-- Backward-compatible with v0.2.0 callsites — existing key-only binds
-- work unchanged.
--
-- v0.2.0 (P.2.6 2026-05-11): bind() accepts string-key-names only.
-- Integer engine.input.KEY_* args are rejected.
--
-- Scope v0.4.0: action-mapping (string-key+mouse-arrays per action) +
-- press-edge + release-edge detection + direction-vector helper.
-- DEPRECATED-MVP: mouse-wheel, mouse-delta helper, side-buttons,
-- gamepad bindings, action-context-stack, key-rebinding config.
-- =====================================================================

-- Unified string → {kind, code} mapping. Lowercase convention.
-- "mouse_*" namespaces avoid collision with arrow-key "left"/"right".
local BIND_MAP = {
    -- Letters (26) — kind="key"
    a = {kind="key", code=engine.input.KEY_A}, b = {kind="key", code=engine.input.KEY_B},
    c = {kind="key", code=engine.input.KEY_C}, d = {kind="key", code=engine.input.KEY_D},
    e = {kind="key", code=engine.input.KEY_E}, f = {kind="key", code=engine.input.KEY_F},
    g = {kind="key", code=engine.input.KEY_G}, h = {kind="key", code=engine.input.KEY_H},
    i = {kind="key", code=engine.input.KEY_I}, j = {kind="key", code=engine.input.KEY_J},
    k = {kind="key", code=engine.input.KEY_K}, l = {kind="key", code=engine.input.KEY_L},
    m = {kind="key", code=engine.input.KEY_M}, n = {kind="key", code=engine.input.KEY_N},
    o = {kind="key", code=engine.input.KEY_O}, p = {kind="key", code=engine.input.KEY_P},
    q = {kind="key", code=engine.input.KEY_Q}, r = {kind="key", code=engine.input.KEY_R},
    s = {kind="key", code=engine.input.KEY_S}, t = {kind="key", code=engine.input.KEY_T},
    u = {kind="key", code=engine.input.KEY_U}, v = {kind="key", code=engine.input.KEY_V},
    w = {kind="key", code=engine.input.KEY_W}, x = {kind="key", code=engine.input.KEY_X},
    y = {kind="key", code=engine.input.KEY_Y}, z = {kind="key", code=engine.input.KEY_Z},
    -- Numbers (10) — kind="key"
    ["0"] = {kind="key", code=engine.input.KEY_ZERO},
    ["1"] = {kind="key", code=engine.input.KEY_ONE},
    ["2"] = {kind="key", code=engine.input.KEY_TWO},
    ["3"] = {kind="key", code=engine.input.KEY_THREE},
    ["4"] = {kind="key", code=engine.input.KEY_FOUR},
    ["5"] = {kind="key", code=engine.input.KEY_FIVE},
    ["6"] = {kind="key", code=engine.input.KEY_SIX},
    ["7"] = {kind="key", code=engine.input.KEY_SEVEN},
    ["8"] = {kind="key", code=engine.input.KEY_EIGHT},
    ["9"] = {kind="key", code=engine.input.KEY_NINE},
    -- Arrows (4) — kind="key"
    left  = {kind="key", code=engine.input.KEY_LEFT},
    right = {kind="key", code=engine.input.KEY_RIGHT},
    up    = {kind="key", code=engine.input.KEY_UP},
    down  = {kind="key", code=engine.input.KEY_DOWN},
    -- Whitespace + control (5) — kind="key"
    space     = {kind="key", code=engine.input.KEY_SPACE},
    tab       = {kind="key", code=engine.input.KEY_TAB},
    enter     = {kind="key", code=engine.input.KEY_ENTER},
    backspace = {kind="key", code=engine.input.KEY_BACKSPACE},
    escape    = {kind="key", code=engine.input.KEY_ESCAPE},
    -- Modifiers (left-side; aliases for ergonomics) — kind="key"
    shift  = {kind="key", code=engine.input.KEY_LEFT_SHIFT},
    lshift = {kind="key", code=engine.input.KEY_LEFT_SHIFT},
    ctrl   = {kind="key", code=engine.input.KEY_LEFT_CONTROL},
    lctrl  = {kind="key", code=engine.input.KEY_LEFT_CONTROL},
    alt    = {kind="key", code=engine.input.KEY_LEFT_ALT},
    lalt   = {kind="key", code=engine.input.KEY_LEFT_ALT},
    -- Console-toggle (DE: ^, US: `) — kind="key"
    ["^"]  = {kind="key", code=engine.input.KEY_GRAVE},
    -- Mouse buttons (3) — kind="mouse" (P.3.3)
    mouse_left   = {kind="mouse", code=engine.input.MOUSE_LEFT},
    mouse_right  = {kind="mouse", code=engine.input.MOUSE_RIGHT},
    mouse_middle = {kind="mouse", code=engine.input.MOUSE_MIDDLE},
}

local bindings = {}  -- action_name -> array of {kind, code} entries

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 {kind, code} entry via BIND_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', 'left', 'space', 'mouse_left', etc. — see BIND_MAP in lib-core.input/init.lua",
                i, action_name, type(k)))
        end
        local entry = BIND_MAP[k]
        if entry == nil then
            error(string.format("input.bind: unknown key-name '%s' for action '%s' — must be lowercase key ('a'..'z', 'left', 'space', ...) or mouse ('mouse_left', 'mouse_right', 'mouse_middle')",
                k, action_name))
        end
        resolved[i] = entry
    end
    bindings[action_name] = resolved
end

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

function M.is_action_down(action_name)
    local entries = bindings[action_name]
    if not entries then return false end
    for _, e in ipairs(entries) do
        if e.kind == "key" and engine.input.is_key_down(e.code) then return true end
        if e.kind == "mouse" and engine.input.is_mouse_down(e.code) then return true end
    end
    return false
end

function M.was_action_pressed(action_name)
    local entries = bindings[action_name]
    if not entries then return false end
    for _, e in ipairs(entries) do
        if e.kind == "key" and engine.input.was_pressed(e.code) then return true end
        if e.kind == "mouse" and engine.input.was_mouse_pressed(e.code) then return true end
    end
    return false
end

function M.was_action_released(action_name)
    local entries = bindings[action_name]
    if not entries then return false end
    for _, e in ipairs(entries) do
        if e.kind == "key"   and engine.input.was_released(e.code)       then return true end
        if e.kind == "mouse" and engine.input.was_mouse_released(e.code) 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 (P.3.3-introduced):
-- mouse-wheel binding (wheel_up/wheel_down) — P.3-future-slice (post-P.3.4); continuous-vs-edge brainstorming needed
-- mouse-delta helper (engine.input.get_mouse_delta) — P.3.5/6 drag-pan / drag-box
-- mouse-button side-buttons (mouse_4 / mouse_5) — additive extension
-- mouse-position lib-wrapper (input.mouse_pos() → {x,y}) — convenience layer
--
-- DEPRECATED-MVP (existing from v0.2.0):
-- bind_gamepad(action, ...)           — gamepad slice
-- push_context(name) / pop_context()  — action-context-stack
-- load_bindings_from_config(path)     — key-rebinding slice
-- right-modifier-keys (rshift/rctrl/ralt)  — engine.input.KEY_RIGHT_* required
-- function-keys (f1..f12) + special-keys (delete/insert/home/end/pageup/pagedown) — engine.input extension required

return M