package realtime

import (
	"encoding/json"
	"net/http"
	"strings"
)

func NewOpenAPIHandler() http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodGet {
			writeError(w, http.StatusMethodNotAllowed, "method not allowed")
			return
		}
		if strings.Trim(r.URL.Path, "/") != "openapi.json" {
			writeError(w, http.StatusNotFound, "route not found")
			return
		}
		w.Header().Set("Content-Type", "application/json")
		_ = json.NewEncoder(w).Encode(realtimeOpenAPISpec())
	})
}

func NewSwaggerUIHandler() http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		if r.Method != http.MethodGet {
			writeError(w, http.StatusMethodNotAllowed, "method not allowed")
			return
		}
		w.Header().Set("Content-Type", "text/html; charset=utf-8")
		_, _ = w.Write([]byte(swaggerHTML))
	})
}

func realtimeOpenAPISpec() map[string]any {
	return map[string]any{
		"openapi": "3.0.3",
		"info": map[string]any{
			"title":       "Lingniu Vehicle Realtime API",
			"version":     "1.0.0",
			"description": "MySQL realtime query APIs for vehicle_realtime_snapshot and vehicle_realtime_location.",
		},
		"paths": map[string]any{
			"/api/realtime/snapshots": map[string]any{
				"get": map[string]any{
					"summary":     "查询车辆实时快照",
					"description": "从 vehicle_realtime_snapshot 查询各协议最新在线快照，支持协议、VIN、车牌过滤和分页。",
					"tags":        []string{"Realtime Snapshot API"},
					"x-table":     "vehicle_realtime_snapshot",
					"parameters":  commonRealtimeParameters(),
					"responses": map[string]any{
						"200": map[string]any{
							"description": "Snapshot page",
							"content": map[string]any{
								"application/json": map[string]any{
									"schema": map[string]any{"$ref": "#/components/schemas/SnapshotPage"},
								},
							},
						},
					},
				},
			},
			"/api/realtime/locations": map[string]any{
				"get": map[string]any{
					"summary":     "查询车辆实时位置",
					"description": "从 vehicle_realtime_location 查询各协议最新位置，支持协议、VIN、车牌过滤和分页。",
					"tags":        []string{"Realtime Location API"},
					"x-table":     "vehicle_realtime_location",
					"parameters":  commonRealtimeParameters(),
					"responses": map[string]any{
						"200": map[string]any{
							"description": "Location page",
							"content": map[string]any{
								"application/json": map[string]any{
									"schema": map[string]any{"$ref": "#/components/schemas/LocationPage"},
								},
							},
						},
					},
				},
			},
		},
		"components": map[string]any{
			"schemas": map[string]any{
				"SnapshotPage": pageSchema("#/components/schemas/SnapshotRow"),
				"LocationPage": pageSchema("#/components/schemas/LocationRow"),
				"SnapshotRow": map[string]any{
					"type": "object",
					"properties": map[string]any{
						"protocol":    stringSchema("GB32960"),
						"vin":         stringSchema("LB9A32A21R0LS1707"),
						"plate":       stringSchema("浙A12345"),
						"event_time":  stringSchema("2026-07-02 16:01:02.123"),
						"received_at": stringSchema("2026-07-02 16:01:03.456"),
						"event_id":    stringSchema("event id"),
						"created_at":  stringSchema("2026-07-02 16:01:03"),
						"updated_at":  stringSchema("2026-07-02 16:01:04"),
					},
				},
				"LocationRow": map[string]any{
					"type": "object",
					"properties": map[string]any{
						"protocol":         stringSchema("JT808"),
						"vin":              stringSchema("LKLG7C4E3NA774736"),
						"plate":            stringSchema("粤B98765"),
						"event_time":       stringSchema("2026-07-02 16:11:02.000"),
						"latitude":         numberSchema(30.123456),
						"longitude":        numberSchema(120.654321),
						"speed_kmh":        numberSchema(54.3),
						"total_mileage_km": numberSchema(48798.9),
						"soc_percent":      numberSchema(81.5),
						"altitude_m":       numberSchema(19.0),
						"direction_deg":    numberSchema(88.0),
						"alarm_flag":       integerSchema(0),
						"status_flag":      integerSchema(3),
						"received_at":      stringSchema("2026-07-02 16:11:03.000"),
						"event_id":         stringSchema("event id"),
						"created_at":       stringSchema("2026-07-02 16:11:03"),
						"updated_at":       stringSchema("2026-07-02 16:11:04"),
					},
				},
			},
		},
	}
}

func commonRealtimeParameters() []map[string]any {
	return []map[string]any{
		{"name": "protocol", "in": "query", "schema": map[string]any{"type": "string", "enum": []string{"GB32960", "JT808", "YUTONG_MQTT"}}, "required": false},
		{"name": "vin", "in": "query", "schema": map[string]any{"type": "string"}, "required": false},
		{"name": "plate", "in": "query", "schema": map[string]any{"type": "string"}, "required": false},
		{"name": "limit", "in": "query", "schema": map[string]any{"type": "integer", "minimum": 1, "maximum": 1000, "default": 50}, "required": false},
		{"name": "offset", "in": "query", "schema": map[string]any{"type": "integer", "minimum": 0, "maximum": 1000000, "default": 0}, "required": false},
	}
}

func pageSchema(itemRef string) map[string]any {
	return map[string]any{
		"type": "object",
		"properties": map[string]any{
			"items":  map[string]any{"type": "array", "items": map[string]any{"$ref": itemRef}},
			"total":  integerSchema(1),
			"limit":  integerSchema(50),
			"offset": integerSchema(0),
		},
	}
}

func stringSchema(example string) map[string]any {
	return map[string]any{"type": "string", "example": example}
}

func numberSchema(example float64) map[string]any {
	return map[string]any{"type": "number", "example": example}
}

func integerSchema(example int64) map[string]any {
	return map[string]any{"type": "integer", "example": example}
}

const swaggerHTML = `<!doctype html>
<html lang="zh-CN">
<head>
  <meta charset="utf-8">
  <title>Lingniu Vehicle Realtime API</title>
  <link rel="stylesheet" href="https://unpkg.com/swagger-ui-dist@5/swagger-ui.css">
</head>
<body>
  <div id="swagger-ui"></div>
  <script src="https://unpkg.com/swagger-ui-dist@5/swagger-ui-bundle.js"></script>
  <script>
    window.ui = SwaggerUIBundle({ url: "/openapi.json", dom_id: "#swagger-ui" });
  </script>
</body>
</html>`