#!/bin/bash
# Fake tmux for testing tmux-util.
#
# State file: $FAKE_TMUX_DIR/sessions.txt
#   One line per session, space-separated:
#     <name> <attached> <pids_csv> [<activity_epoch> [<windows> [<cwd>]]]
#   pids_csv is a comma-separated list of pane PIDs (or '-' for none)
#   cwd cannot contain spaces in test data.
#
# Log file: $FAKE_TMUX_DIR/calls.log
#   Each invocation appended as a single line: tmux <args>

: "${FAKE_TMUX_DIR:?FAKE_TMUX_DIR must be set}"

STATE="$FAKE_TMUX_DIR/sessions.txt"
LOG="$FAKE_TMUX_DIR/calls.log"

# Log every invocation
printf 'tmux %s\n' "$*" >> "$LOG"

cmd="$1"
shift

read_state() {
    [ -f "$STATE" ] || return 0
    grep -v '^[[:space:]]*$' "$STATE" || true
}

# Render a tmux format string against one session's fields.
# Args: format, name, attached, activity, windows, cwd
render_format() {
    local out="$1" name="$2" attached="$3" activity="$4" windows="$5" cwd="$6"
    out="${out//\#\{session_name\}/$name}"
    out="${out//\#\{session_attached\}/$attached}"
    out="${out//\#\{session_activity\}/$activity}"
    out="${out//\#\{session_windows\}/$windows}"
    out="${out//\#\{pane_current_path\}/$cwd}"
    echo "$out"
}

# Render a tmux format string against one pane's fields.
# Args: format, name, pid, cmd, idx, cwd
render_pane_format() {
    local out="$1" name="$2" pid="$3" cmd="$4" idx="$5" cwd="$6"
    out="${out//\#\{pane_pid\}/$pid}"
    out="${out//\#\{pane_current_command\}/$cmd}"
    out="${out//\#\{pane_current_path\}/$cwd}"
    out="${out//\#\{session_name\}/$name}"
    out="${out//\#\{window_index\}/0}"
    out="${out//\#\{pane_index\}/$idx}"
    echo "$out"
}

case "$cmd" in
    list-sessions)
        fmt=""
        while [ "$#" -gt 0 ]; do
            case "$1" in
                -F) shift; fmt="${1:-}"; shift ;;
                *)  shift ;;
            esac
        done
        [ -n "$fmt" ] || fmt='#{session_name} #{session_attached}'
        read_state | while IFS=' ' read -r name attached pids activity windows cwd; do
            [ -n "$name" ] || continue
            render_format "$fmt" "$name" "$attached" "${activity:-0}" "${windows:-1}" "${cwd:-/tmp}"
        done
        ;;
    list-panes)
        all=0
        fmt=""
        session=""
        while [ "$#" -gt 0 ]; do
            case "$1" in
                -t) shift; session="$1"; shift ;;
                -F) shift; fmt="${1:-}"; shift ;;
                -s) shift ;;
                -a) all=1; shift ;;
                *)  shift ;;
            esac
        done
        [ -n "$fmt" ] || fmt='#{pane_pid}'
        read_state | while IFS=' ' read -r name attached pids activity windows cwd; do
            [ -n "$name" ] || continue
            if [ "$all" -eq 0 ] && [ "$name" != "$session" ]; then
                continue
            fi
            [ "$pids" = "-" ] && continue
            idx=0
            for entry in $(echo "$pids" | tr ',' ' '); do
                pid="${entry%%:*}"
                cmd="${entry##*:}"
                [ "$cmd" = "$entry" ] && cmd="shell"
                render_pane_format "$fmt" "$name" "$pid" "$cmd" "$idx" "${cwd:-/tmp}"
                idx=$((idx + 1))
            done
        done
        ;;
    display)
        fmt=""
        target=""
        while [ "$#" -gt 0 ]; do
            case "$1" in
                -p) shift ;;
                -t) shift; target="$1"; shift ;;
                *) fmt="$1"; shift ;;
            esac
        done
        while IFS=' ' read -r name attached pids activity windows cwd; do
            [ -n "$name" ] || continue
            if [ "$name" = "$target" ]; then
                render_format "$fmt" "$name" "$attached" "${activity:-0}" "${windows:-1}" "${cwd:-/tmp}"
                exit 0
            fi
        done < "$STATE"
        exit 1
        ;;
    has-session)
        session=""
        while [ "$#" -gt 0 ]; do
            case "$1" in
                -t) shift; session="$1"; shift ;;
                *)  shift ;;
            esac
        done
        # tmux accepts a `=name` form to force exact match; strip the prefix.
        session="${session#=}"
        while IFS=' ' read -r name attached pids _rest; do
            if [ "$name" = "$session" ]; then
                exit 0
            fi
        done < "$STATE"
        exit 1
        ;;
    new-session)
        detached=0
        name=""
        cwd=""
        while [ "$#" -gt 0 ]; do
            case "$1" in
                -s) shift; name="$1"; shift ;;
                -c) shift; cwd="$1"; shift ;;
                -d) detached=1; shift ;;
                *)  shift ;;
            esac
        done
        attached=1
        [ "$detached" -eq 1 ] && attached=0
        printf '%s %s - 0 1 %s\n' "$name" "$attached" "${cwd:-/tmp}" >> "$STATE"
        ;;
    attach-session|switch-client)
        # No state mutation needed — the call log already records intent.
        ;;
    rename-session)
        # Forms: rename-session -t <old> <new>   OR   rename-session <new>
        old=""
        new=""
        while [ "$#" -gt 0 ]; do
            case "$1" in
                -t) shift; old="$1"; shift ;;
                *)  new="$1"; shift ;;
            esac
        done
        if [ -z "$old" ] || [ -z "$new" ]; then
            echo "fake-tmux rename-session: need both -t <old> and <new>" >&2
            exit 1
        fi
        tmp="$STATE.tmp"
        : > "$tmp"
        while IFS= read -r line; do
            [ -n "$line" ] || continue
            first="${line%% *}"
            rest="${line#* }"
            if [ "$first" = "$old" ]; then
                printf '%s %s\n' "$new" "$rest" >> "$tmp"
            else
                printf '%s\n' "$line" >> "$tmp"
            fi
        done < "$STATE"
        mv "$tmp" "$STATE"
        ;;
    kill-session)
        session=""
        while [ "$#" -gt 0 ]; do
            case "$1" in
                -t) shift; session="$1"; shift ;;
                *)  shift ;;
            esac
        done
        tmp="$STATE.tmp"
        : > "$tmp"
        while IFS= read -r line; do
            [ -n "$line" ] || continue
            first="${line%% *}"
            if [ "$first" != "$session" ]; then
                printf '%s\n' "$line" >> "$tmp"
            fi
        done < "$STATE"
        mv "$tmp" "$STATE"
        ;;
    *)
        echo "fake-tmux: unknown command '$cmd'" >&2
        exit 1
        ;;
esac