"""
地图生成主流程控制器。
协调模板加载、图层过滤、缩放、文本更新、导出。
"""
import os
import time

from qgis.core import QgsProject, QgsDataSourceUri

from app.config.paths import get_logger
from app.config.qgis_mappings import TABLE_RENAMES, SCHEMA_REPLACEMENTS
from .template_cache import TemplateCache
from .template_modifier import TemplateModifier
from .layer_filter import LayerFilter
from .map_exporter import MapExporter
from app.utils.map_zoom import MapZoom

logger = get_logger("qgis.service")

# 全局模板缓存（跨请求复用）
template_cache = TemplateCache()


class MapService:
    def __init__(self, config: dict):
        self.config = config

    def generate(self, model: dict) -> str:
        """
        执行完整的地图生成流程。
        """
        _timing = {}  # {step: seconds}
        t_total = time.time()

        template_path = model["path"]
        template_name = os.path.basename(template_path)
        project = QgsProject.instance()
        is_cache_hit = template_cache.is_loaded(template_path)

        # ── 步骤 1：加载/恢复模板 ──
        t0 = time.time()
        if is_cache_hit:
            logger.info(f"[缓存命中] {template_name}")
            project, texts, extent = template_cache.restore_template(template_path)
            template_cache.reset_project_state(project, texts, extent)
            # FlagDontResolveLayers 跳过了数据库连接，手动触发 PostgreSQL 图层解析
            self._resolve_postgres_layers(project)
        else:
            logger.info(f"[首次加载] {template_name}")
            modifier = TemplateModifier(self.config)
            actual_path = modifier.modify(template_path)
            project.read(actual_path)
            if actual_path != template_path:
                try:
                    os.remove(actual_path)
                except OSError:
                    pass
        _timing["1.load"] = time.time() - t0

        # ── 步骤 2：图层连接修正 ──
        t0 = time.time()
        if not is_cache_hit:
            self._fix_invalid_layers(project)
        _timing["2.connections"] = time.time() - t0

        # ★ 首次加载完成后再保存缓存（确保图层已修正）
        if not is_cache_hit:
            template_cache.save_current(template_path, model.get("mapLayout", "A3"))

        # ── 步骤 3：图层过滤 ──
        t0 = time.time()
        LayerFilter().apply(project, model)
        _timing["3.filter"] = time.time() - t0

        # ── 步骤 4：地图缩放 ──
        t0 = time.time()
        layout = project.layoutManager().layoutByName(model["mapLayout"])
        if layout is None:
            available = [l.name() for l in project.layoutManager().layouts()]
            raise RuntimeError(
                f"模板中未找到布局 '{model['mapLayout']}'，可用布局：{available}"
            )
        map_item = layout.itemById("Map")
        zoom = MapZoom(project, layout, map_item)
        zoom.execute(model["zoomRule"], {
            "X": model["centerX"],
            "Y": model["centerY"],
            "value": model["zoomValue"],
        })
        _timing["4.zoom"] = time.time() - t0

        # ── 步骤 5：文本 + 比例尺 + 导出 ──
        t0 = time.time()
        exporter = MapExporter(self.config, layout)
        exporter.update_texts(model)
        exporter.update_scale_bar()
        exporter.export(model["outFile"])
        _timing["5.export"] = time.time() - t0

        total = time.time() - t_total
        steps = ", ".join(f"{k}={v:.1f}s" for k, v in _timing.items())
        logger.info(
            f"{'[缓存命中]' if is_cache_hit else '[首次加载]'} "
            f"{template_name} → {total:.1f}s ({steps})"
        )
        return model["name"]

    def _fix_invalid_layers(self, project: QgsProject) -> None:
        """只修复 TemplateModifier 处理后仍无效的图层（TemplateModifier 已修正大部分连接）"""
        t0 = time.time()
        db_config = self.config["db"]
        override = self.config.get("template_override", {})
        actual_schema = override.get("actual", {}).get("schema", "qgis")

        fixed = 0
        failed = 0
        total = 0
        for layer in project.mapLayers().values():
            if layer.providerType() != "postgres":
                continue
            total += 1
            if layer.isValid():
                continue  # TemplateModifier 已修正，跳过
            try:
                self._fix_postgres_layer(layer, db_config, actual_schema)
                if layer.isValid():
                    fixed += 1
                else:
                    failed += 1
            except Exception as e:
                logger.error(f"  修复图层 {layer.name()} 失败: {e}")
                failed += 1

        elapsed = time.time() - t0
        if total:
            logger.info(
                f"  图层修正: 总计{total}个PG层, 跳过{total - fixed - failed}(已有效), "
                f"修复{fixed}, 仍失败{failed}, 耗时{elapsed:.1f}s"
            )

    @staticmethod
    def _resolve_postgres_layers(project: QgsProject) -> None:
        """FlagDontResolveLayers 跳过了数据库连接，重新 setDataSource 触发"""
        for layer in project.mapLayers().values():
            if layer.providerType() != "postgres":
                continue
            try:
                source = layer.source()
                if source:
                    layer.setDataSource(source, layer.name(), "postgres")
            except Exception:
                pass

    @staticmethod
    def _fix_postgres_layer(layer, db_config, actual_schema):
        """修正单个 PostgreSQL 图层的连接参数"""
        try:
            uri = layer.dataProvider().uri()
            uri.setConnection(
                db_config["host"],
                str(db_config["port"]),
                db_config["database"],
                db_config["username"],
                db_config["password"],
            )
            # Schema 替换
            uri_str = uri.uri()
            for old_schema in SCHEMA_REPLACEMENTS:
                if f'table="{old_schema}".' in uri_str:
                    uri_str = uri_str.replace(
                        f'table="{old_schema}".',
                        f'table="{actual_schema}".',
                    )
                    uri = QgsDataSourceUri(uri_str)
                    break
            # 表名映射
            uri_str = uri.uri()
            for old_name, new_name in TABLE_RENAMES.items():
                full_old = f'table="{actual_schema}"."{old_name}"'
                full_new = f'table="{actual_schema}"."{new_name}"'
                if full_old in uri_str:
                    uri_str = uri_str.replace(full_old, full_new)
                    uri = QgsDataSourceUri(uri_str)
            # SRID 修正
            uri_str = uri.uri()
            if " srid=0 " in uri_str:
                uri_str = uri_str.replace(" srid=0 ", " srid=4326 ")
                uri = QgsDataSourceUri(uri_str)

            layer.setDataSource(uri.uri(), layer.name(), "postgres")

            if layer.isValid():
                logger.debug(f"  图层 {layer.name()} 连接更新成功")
            else:
                logger.error(f"  图层 {layer.name()} 更新后仍无效")
        except Exception as e:
            logger.error(f"  更新图层 {layer.name()} 连接失败: {e}")