package sync

import (
	"context"
	"fmt"
	"strings"

	"gitea.redpowerfuture.com/red-future/common/db/gfdb"
	"github.com/sirupsen/logrus"
)

// ColumnDef 列定义
type ColumnDef struct {
	Name    string `json:"name"`
	Type    string `json:"type"`
	Comment string `json:"comment,omitempty"`
}

// TableDefinition 表结构定义
type TableDefinition struct {
	TableName    string      `json:"table_name"`
	Columns      []ColumnDef `json:"columns"`
	ConflictKeys []string    `json:"conflict_keys,omitempty"`
}

// ParseTableDefinition 解析 table_definition JSON
func ParseTableDefinition(raw map[string]interface{}) (*TableDefinition, error) {
	td := &TableDefinition{}
	name, _ := raw["table_name"].(string)
	if name == "" {
		return nil, fmt.Errorf("table_definition 缺少 table_name")
	}
	td.TableName = name

	colsRaw, _ := raw["columns"].([]interface{})
	for _, c := range colsRaw {
		cm, _ := c.(map[string]interface{})
		if cm == nil {
			continue
		}
		n, _ := cm["name"].(string)
		t, _ := cm["type"].(string)
		comment, _ := cm["comment"].(string)
		if n == "" || t == "" {
			continue
		}
		td.Columns = append(td.Columns, ColumnDef{Name: n, Type: t, Comment: comment})
	}
	if keys, _ := raw["conflict_keys"].([]interface{}); keys != nil {
		for _, k := range keys {
			if s, ok := k.(string); ok {
				td.ConflictKeys = append(td.ConflictKeys, s)
			}
		}
	}
	if len(td.Columns) == 0 {
		return nil, fmt.Errorf("table_definition 列定义为空")
	}
	return td, nil
}

// EnsureTable 确保表存在
func EnsureTable(ctx context.Context, td *TableDefinition) error {
	sql := buildCreateSQL(td)
	logrus.Infof("建表: %s", td.TableName)
	_, err := gfdb.DB(ctx).Exec(ctx, sql)
	if err != nil {
		return fmt.Errorf("建表失败 [%s]: %w", td.TableName, err)
	}
	logrus.Infof("表 %s 已就绪", td.TableName)
	return nil
}

func buildCreateSQL(td *TableDefinition) string {
	cols := []string{
		"id BIGSERIAL PRIMARY KEY",
		"tenant_id BIGINT NOT NULL DEFAULT 0",
		"creator VARCHAR(64) DEFAULT ''",
		"created_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()",
		"updater VARCHAR(64) DEFAULT ''",
		"updated_at TIMESTAMP WITH TIME ZONE DEFAULT NOW()",
		"deleted_at TIMESTAMP WITH TIME ZONE",
	}
	for _, c := range td.Columns {
		cols = append(cols, fmt.Sprintf("%s %s", c.Name, c.Type))
	}
	cols = append(cols, "raw_data JSONB DEFAULT '{}'")

	// 添加复合唯一索引（用于 ON CONFLICT upsert）
	var constraints []string
	if len(td.ConflictKeys) > 0 {
		ck := strings.Join(td.ConflictKeys, ", ")
		indexName := fmt.Sprintf("uq_%s_conflict", td.TableName)
		constraints = append(constraints,
			fmt.Sprintf("CREATE UNIQUE INDEX IF NOT EXISTS %s ON %s (%s)", indexName, td.TableName, ck))
	}

	sql := fmt.Sprintf("CREATE TABLE IF NOT EXISTS %s (\n  %s\n);\n", td.TableName, strings.Join(cols, ",\n  "))

	// 添加唯一索引
	if len(constraints) > 0 {
		sql += strings.Join(constraints, ";\n") + ";\n"
	}

	// 添加字段注释（COMMENT ON COLUMN）
	for _, c := range td.Columns {
		if c.Comment != "" {
			escaped := strings.ReplaceAll(c.Comment, "'", "''")
			sql += fmt.Sprintf("COMMENT ON COLUMN %s.%s IS '%s';\n", td.TableName, c.Name, escaped)
		}
	}

	return sql
}