# Copyright (C) 2026 Rootiest
# SPDX-License-Identifier: AGPL-3.0-or-later

# SYNOPSIS
#   config-settings [-h | --help]
#
# DESCRIPTION
#   Opens an interactive full-screen TUI for managing fish config settings,
#   including the six opinionated component categories (C1–C6) and the master
#   disable variable, without having to remember variable names. Two scope
#   tabs allow independent per-scope configuration:
#
#     Universal — persists across all sessions (set -U / set -Ue)
#     Session   — active for the current shell only (set -g / set -eg)
#
#   Values are changed directionally with the arrow keys (or vim-style h/l)
#   along an OFF ← DEFAULT → ON scale, and apply immediately — no confirm
#   step. Always available regardless of __fish_config_opinionated state.
#
# ARGUMENTS
#   -h, --help  Print usage and exit
#
# RETURNS
#   0  Exited normally (q or Escape pressed)
#   1  Unknown flag passed
#
# EXAMPLE
#   config-settings
function config-settings --description 'Interactive TUI for managing fish config settings'
    set -l c_head  (set_color --bold cyan)
    set -l c_cmd   (set_color --bold white)
    set -l c_flag  (set_color yellow)
    set -l c_dim   (set_color brblack)
    set -l c_err   (set_color red)
    set -l c_reset (set_color normal)

    # ── Argument parsing ──────────────────────────────────
    for arg in $argv
        switch $arg
            case -h --help
                echo "$c_head""Usage:$c_reset $c_cmd""config-settings$c_reset $c_flag""[-h]$c_reset"
                echo
                echo "  Interactive TUI for managing fish config settings."
                echo "  Changes apply immediately — no confirm step required."
                echo
                echo "$c_head""Navigation:$c_reset"
                echo "  $c_flag↑ ↓$c_reset or $c_flag""k j$c_reset    Move cursor up / down"
                echo "  $c_flag← →$c_reset or $c_flag""h l$c_reset    Set value: OFF ← DEFAULT → ON"
                echo "  $c_flag""Tab$c_reset           Switch scope (Universal ↔ Session)"
                echo "  $c_flag""Enter$c_reset         Edit path (on Dots Path row)"
                echo "  $c_flag""q$c_reset / $c_flag""Esc$c_reset       Exit"
                echo
                echo "$c_head""Scopes:$c_reset"
                echo "  $c_flag""Universal$c_reset   Persistent across all sessions ($c_dim""set -U$c_reset)"
                echo "  $c_flag""Session$c_reset     Current session only ($c_dim""set -g$c_reset)"
                return 0
            case '*'
                echo "$c_err""Unknown option: $arg$c_reset" >&2
                echo "Run $c_cmd""config-settings --help$c_reset for usage." >&2
                return 1
        end
    end

    # ── Variable list (matches Panel Layout Reference) ────
    set -l vars \
        __fish_config_op_aliases \
        __fish_config_op_autoexec \
        __fish_config_op_overrides \
        __fish_config_op_integrations \
        __fish_config_op_logging \
        __fish_config_op_greeting \
        __fish_config_opinionated \
        __fish_user_dots_path

    set -l cur_row   0           # 0–7
    set -l cur_scope universal   # or "session"
    set -l panel_h   16          # total panel lines (all width tiers are 16 lines)
    set -l last_cols $COLUMNS    # COLUMNS at the time of the last draw

    # ── Terminal setup ────────────────────────────────────
    printf '\e[?25l'             # hide cursor
    trap 'printf "\e[?25h"; set -g __config_settings_exit 1' INT

    # ── Initial draw ──────────────────────────────────────
    __config_settings_draw $cur_row $cur_scope $vars

    # ── Event loop ────────────────────────────────────────
    # __config_settings_read_key reads a single keypress from /dev/tty in raw
    # mode and returns a normalized token (up/down/tab/space/escape/quit or a
    # literal char). It bypasses fish's `read`, whose line editor swallows Tab
    # and arrow keys and prints a `read> ` prompt — unusable for a TUI.
    while true
        # Check for Ctrl-C signal (trap sets this flag during redraw, when the
        # terminal is briefly back in cooked mode and SIGINT can fire).
        if set -q __config_settings_exit
            set -eg __config_settings_exit
            break
        end

        set -l key (__config_settings_read_key)
        or break   # not a TTY — exit instead of spinning

        set -l did_redraw 0

        switch $key
            case up k
                set cur_row (math "max(0, $cur_row - 1)")
            case down j
                set cur_row (math "min(7, $cur_row + 1)")
            case tab      # Tab — switch scope
                if test $cur_scope = universal
                    set cur_scope session
                else
                    set cur_scope universal
                end
            case enter
                if test $cur_row -eq 7
                    # Erase panel (wrap-aware, same formula as cleanup)
                    set -l prev_max_lw (math --scale=0 "($last_cols + 78) / 2")
                    set -l erase_h (math --scale=0 "$panel_h * max(1, ceil($prev_max_lw / $COLUMNS))")
                    printf '\e[%dA\e[J' $erase_h
                    printf '\e[?25h'     # restore cursor

                    printf 'User Dots Path (leave blank to reset to default): '
                    read -l new_path

                    if test -n "$new_path"
                        set -U __fish_user_dots_path $new_path
                    else
                        set -Ue __fish_user_dots_path
                    end

                    printf '\e[?25l'    # hide cursor
                    set last_cols $COLUMNS
                    __config_settings_draw $cur_row $cur_scope $vars
                    set did_redraw 1
                end
            case right l   # → / l — step toward ON (clamped, no wrap)
                if test $cur_row -eq 7
                    # no-op for path var; use Enter to set
                else
                    set -l varname $vars[(math $cur_row + 1)]
                    set -l cur_val (__config_settings_get_val $varname $cur_scope)

                    set -l next_val on
                    switch $cur_val
                        case off
                            set next_val DEFAULT
                        case on
                            set next_val on
                        case '*'
                            set next_val on
                    end
                    __config_settings_apply $varname $cur_scope $next_val
                end
            case left h   # ← / h — step toward OFF (clamped, no wrap)
                if test $cur_row -eq 7
                    # Clear the universal path var (restore default)
                    __config_settings_apply __fish_user_dots_path universal DEFAULT
                else
                    set -l varname $vars[(math $cur_row + 1)]
                    set -l cur_val (__config_settings_get_val $varname $cur_scope)

                    set -l next_val off
                    switch $cur_val
                        case on
                            set next_val DEFAULT
                        case off
                            set next_val off
                        case '*'
                            set next_val off
                    end
                    __config_settings_apply $varname $cur_scope $next_val
                end
            case q Q quit escape
                break
        end

        # Skip redraw entirely when the key reader timed out with no resize
        if test -z "$key" -a "$COLUMNS" = "$last_cols"
            continue
        end

        # Skip redraw if the Enter handler already redrew (e.g. after path edit)
        if test $did_redraw -eq 1
            continue
        end

        # Wrap-aware erase: a panel drawn on a wider terminal has longer lines
        # (due to center-padding) that wrap into extra physical rows when the
        # terminal narrows. 78 = widest box (IW=76+2); the formula gives the
        # worst-case old line width for any tier drawn at last_cols.
        set -l prev_max_lw (math --scale=0 "($last_cols + 78) / 2")
        set -l erase_h (math --scale=0 "$panel_h * max(1, ceil($prev_max_lw / $COLUMNS))")
        printf '\e[%dA\e[J' $erase_h
        set last_cols $COLUMNS
        __config_settings_draw $cur_row $cur_scope $vars
    end

    # ── Cleanup ───────────────────────────────────────────
    trap - INT              # remove the signal handler
    set -l prev_max_lw (math --scale=0 "($last_cols + 78) / 2")
    set -l erase_h (math --scale=0 "$panel_h * max(1, ceil($prev_max_lw / $COLUMNS))")
    printf '\e[%dA\e[J' $erase_h   # erase the panel (wrap-aware)
    printf '\e[?25h'        # restore cursor
end