#!/usr/bin/env bash

if [ -n "${_LIB_ROLLBACK_SOURCED:-}" ]; then
    return 0
fi
_LIB_ROLLBACK_SOURCED=1

BOOTSTRAP_STATE_DIR="$HOME/.local/state/bootstrap"
BOOTSTRAP_HISTORY_LOG="$BOOTSTRAP_STATE_DIR/history.log"
BOOTSTRAP_UNINSTALLERS_DIR="$BOOTSTRAP_STATE_DIR/uninstallers"
BOOTSTRAP_PACKAGES_DIR="$BOOTSTRAP_STATE_DIR/packages"

init_rollback_system() {
    mkdir -p "$BOOTSTRAP_UNINSTALLERS_DIR"
    mkdir -p "$BOOTSTRAP_PACKAGES_DIR"
    touch "$BOOTSTRAP_HISTORY_LOG"
}

setup_uninstaller_context() {
    local tool="$1"
    export BOOTSTRAP_CURRENT_TOOL="$tool"
    export BOOTSTRAP_UNINSTALLER_CMDS="$BOOTSTRAP_UNINSTALLERS_DIR/${tool}.cmds"
    # Ensure fresh manifest for this run
    rm -f "$BOOTSTRAP_UNINSTALLER_CMDS"
    touch "$BOOTSTRAP_UNINSTALLER_CMDS"
}

add_rollback_cmd() {
    local cmd="$1"
    if [ -n "${BOOTSTRAP_UNINSTALLER_CMDS:-}" ] && [ -f "$BOOTSTRAP_UNINSTALLER_CMDS" ]; then
        # Prepend to the top of the file
        sed -i "1i $cmd" "$BOOTSTRAP_UNINSTALLER_CMDS"
    fi
}

track_file() {
    add_rollback_cmd "sudo rm -f '$1'"
}

track_dir() {
    add_rollback_cmd "sudo rm -rf '$1'"
}

create_savepoint() {
    local name="$1"
    echo "SAVEPOINT: $name" >> "$BOOTSTRAP_HISTORY_LOG"
    log_success "Savepoint '$name' created."
}

mark_install_success() {
    local tool="$1"
    # Only record if we actually have an uninstaller
    if [ -f "$BOOTSTRAP_UNINSTALLERS_DIR/${tool}.cmds" ]; then
        echo "INSTALL: $tool" >> "$BOOTSTRAP_HISTORY_LOG"
    fi
}

execute_rollback() {
    local tool="$1"
    local manifest="$BOOTSTRAP_UNINSTALLERS_DIR/${tool}.cmds"
    
    if [ ! -f "$manifest" ]; then
        log_warn "No rollback manifest found for '$tool'."
        return 0
    fi
    
    export BOOTSTRAP_CURRENT_TOOL="$tool"
    log_info "Rolling back '$tool'..."
    while IFS= read -r cmd; do
        [ -z "$cmd" ] && continue
        log_info "Executing: $cmd"
        eval "$cmd" || log_warn "Failed to execute: $cmd"
    done < "$manifest"
    
    rm -f "$manifest"
    log_success "Rollback of '$tool' complete."
}

rollback_bare() {
    if [ ! -s "$BOOTSTRAP_HISTORY_LOG" ]; then
        log_info "No history available to rollback."
        return 0
    fi
    
    local last_line
    last_line=$(tail -n 1 "$BOOTSTRAP_HISTORY_LOG")
    
    if [[ "$last_line" == INSTALL:* ]]; then
        local tool="${last_line#INSTALL: }"
        execute_rollback "$tool"
        # Remove the last line efficiently
        sed -i '$ d' "$BOOTSTRAP_HISTORY_LOG"
    elif [[ "$last_line" == SAVEPOINT:* ]]; then
        local sp="${last_line#SAVEPOINT: }"
        log_warn "Last action was savepoint '$sp'. Cannot bare-rollback a savepoint."
    fi
}

rollback_to_savepoint() {
    local target_sp="$1"
    
    if ! grep -q "SAVEPOINT: $target_sp" "$BOOTSTRAP_HISTORY_LOG"; then
        log_error "Savepoint '$target_sp' not found in history."
        return 1
    fi
    
    while [ -s "$BOOTSTRAP_HISTORY_LOG" ]; do
        local last_line
        last_line=$(tail -n 1 "$BOOTSTRAP_HISTORY_LOG")
        
        if [[ "$last_line" == SAVEPOINT:\ $target_sp ]]; then
            log_success "Reached savepoint '$target_sp'."
            # Optionally remove the savepoint itself or keep it? Let's keep it.
            break
        elif [[ "$last_line" == INSTALL:* ]]; then
            local tool="${last_line#INSTALL: }"
            execute_rollback "$tool"
            sed -i '$ d' "$BOOTSTRAP_HISTORY_LOG"
        elif [[ "$last_line" == SAVEPOINT:* ]]; then
            local sp="${last_line#SAVEPOINT: }"
            log_info "Removing intermediate savepoint '$sp'..."
            sed -i '$ d' "$BOOTSTRAP_HISTORY_LOG"
        else
            # Unknown line format, just remove it
            sed -i '$ d' "$BOOTSTRAP_HISTORY_LOG"
        fi
    done
}

export -f init_rollback_system setup_uninstaller_context add_rollback_cmd track_file track_dir create_savepoint mark_install_success execute_rollback rollback_bare rollback_to_savepoint