#!/bin/bash
# Shared contract and execution helpers for maint scenario transports.

# Extract one declared variable from a scenario file in a clean subshell.
_scenario_var() {  # <file> <varname>
    bash -c 'set -eu; source "$1" || exit 9; eval "printf %s \"\${$2-}\""' \
        _probe "$1" "$2" 2>/dev/null
}

_validate_scenario() {  # <file> -> fatal on contract violation
    local f="$1" base probe_err
    base=$(basename "$f")
    probe_err=$(bash -c 'set -eu; source "$1"
        : "${SCENARIO_DESC:?missing SCENARIO_DESC}"
        : "${SCENARIO_GROUP:?missing SCENARIO_GROUP}"
        : "${SCENARIO_PROFILES:?missing SCENARIO_PROFILES}"
        for p in $SCENARIO_PROFILES; do
            case "$p" in btrfs|zfs|any) ;; *)
                echo "bad profile token: $p" >&2; exit 1 ;;
            esac
        done
        declare -f scenario_break scenario_fix scenario_assert >/dev/null \
            || { echo "missing scenario_break/fix/assert" >&2; exit 1; }' \
        _probe "$f" 2>&1 >/dev/null) \
        || fatal "scenario contract violation in $base: $probe_err"
}

run_scenario() {  # <index>
    local i="$1" name="${S_NAMES[$1]}" f="${S_FILES[$1]}"
    section "Scenario: $name — ${S_DESCS[$1]}"
    # shellcheck disable=SC1090
    source "$f"
    local ok=true
    step "break"
    if ! scenario_break; then
        error "$name: break step failed"
        ok=false
    fi
    if [ "$ok" = "true" ]; then
        step "fix"
        if ! scenario_fix; then
            error "$name: fix step failed"
            ok=false
        fi
    fi
    if [ "$ok" = "true" ]; then
        step "assert"
        if ! scenario_assert; then
            error "$name: post-state assertion failed"
            ok=false
        fi
    fi
    unset -f scenario_break scenario_fix scenario_assert
    unset SCENARIO_DESC SCENARIO_GROUP SCENARIO_PROFILES
    if [ "$ok" = "true" ]; then
        success "PASS: $name"
        PASS+=("$name")
    else
        error "FAIL: $name"
        FAIL+=("$name")
    fi
}