#!/bin/bash

set -euo pipefail

ENV_FILE="${1:-.env}"
PROJECT_ROOT="${2:-$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)}"
MIGRATIONS_DIR="${UPDATE_ENV_MIGRATIONS_DIR:-$PROJECT_ROOT/scripts/update-env.d}"

if [ ! -f "$ENV_FILE" ]; then
    echo "❌ 环境配置文件不存在: $ENV_FILE" >&2
    exit 1
fi

if [ ! -d "$MIGRATIONS_DIR" ]; then
    echo "ℹ️ 未发现环境配置迁移目录，跳过"
    exit 0
fi

read_env_value() {
    local file="$1"
    local key="$2"
    local value
    value="$(awk -v key="$key" 'index($0, key "=") == 1 { print substr($0, length(key) + 2); exit }' "$file")"
    value="$(printf '%s' "$value" | sed 's/^[[:space:]]*//;s/[[:space:]]*$//')"
    case "$value" in
        \"*\") value="${value#\"}"; value="${value%\"}" ;;
        \'*\') value="${value#\'}"; value="${value%\'}" ;;
    esac
    printf '%s' "$value"
}

write_env_value() {
    local file="$1"
    local key="$2"
    local value="$3"
    local temporary
    temporary="$(mktemp "${file}.tmp.XXXXXX")"
    awk -v key="$key" -v value="$value" '
        BEGIN { replaced = 0 }
        index($0, key "=") == 1 {
            if (!replaced) {
                print key "=" value
                replaced = 1
            }
            next
        }
        { print }
        END { if (!replaced) print key "=" value }
    ' "$file" > "$temporary"
    chmod 600 "$temporary"
    mv "$temporary" "$file"
}

apply_default() {
    local key="$1"
    local value="$2"
    if [ -n "$(read_env_value "$ENV_FILE" "$key")" ]; then
        return 0
    fi
    write_env_value "$ENV_FILE" "$key" "$value"
    echo "   ✓ 已补充环境配置: $key"
}

ensure_list_item() {
    local key="$1"
    local item="$2"
    local current normalized
    current="$(read_env_value "$ENV_FILE" "$key")"
    normalized="$(printf '%s' "$current" | tr -d '[:space:]')"
    case ",${normalized}," in
        *",${item},"*) return 0 ;;
    esac
    if [ -n "$current" ]; then
        current="${current},${item}"
    else
        current="$item"
    fi
    write_env_value "$ENV_FILE" "$key" "$current"
    echo "   ✓ 已补充环境配置项: $key"
}

validate_manifest() {
    local manifest="$1"
    local line line_number=0
    while IFS= read -r line || [ -n "$line" ]; do
        line_number=$((line_number + 1))
        line="${line%$'\r'}"
        case "$line" in
            ""|'#'*) continue ;;
        esac
        if [[ "$line" =~ ^@skip-if[[:space:]]+[A-Z][A-Z0-9_]*=.+$ ]]; then
            continue
        fi
        if ! [[ "$line" =~ ^[A-Z][A-Z0-9_]*(\+)?=.+$ ]]; then
            echo "❌ 无效的环境配置迁移: ${manifest}:${line_number}" >&2
            return 1
        fi
    done < "$manifest"
}

apply_manifest() {
    local manifest="$1"
    local line key value current
    while IFS= read -r line || [ -n "$line" ]; do
        line="${line%$'\r'}"
        if [[ "$line" =~ ^@skip-if[[:space:]]+([A-Z][A-Z0-9_]*)=(.+)$ ]]; then
            key="${BASH_REMATCH[1]}"
            value="${BASH_REMATCH[2]}"
            current="$(read_env_value "$ENV_FILE" "$key")"
            if [ "$current" = "$value" ]; then
                echo "ℹ️ 保留现有更新模式，跳过环境配置迁移: $(basename "$manifest")"
                return 0
            fi
        fi
    done < "$manifest"
    echo "📝 应用环境配置迁移: $(basename "$manifest")"
    while IFS= read -r line || [ -n "$line" ]; do
        line="${line%$'\r'}"
        case "$line" in
            ""|'#'*) continue ;;
        esac
        if [[ "$line" == @skip-if* ]]; then
            continue
        fi
        if [[ "$line" == *'+='* ]]; then
            key="${line%%+=*}"
            value="${line#*+=}"
            ensure_list_item "$key" "$value"
        else
            key="${line%%=*}"
            value="${line#*=}"
            apply_default "$key" "$value"
        fi
    done < "$manifest"
}

shopt -s nullglob
manifests=("$MIGRATIONS_DIR"/*.env)
if [ "${#manifests[@]}" -eq 0 ]; then
    echo "ℹ️ 未发现环境配置迁移文件，跳过"
    exit 0
fi

for manifest in "${manifests[@]}"; do
    validate_manifest "$manifest"
done
for manifest in "${manifests[@]}"; do
    apply_manifest "$manifest"
done

chmod 600 "$ENV_FILE"