package api

import (
	_ "embed"
	"encoding/json"
	"fmt"
	"net/http"
	"strings"

	"github.com/restxlsx/restxlsx/internal/excel"
)

//go:embed swagger-ui.html
var swaggerHTML string

type OpenAPI struct {
	engine *excel.Engine
	debug  bool
}

func NewOpenAPI(engine *excel.Engine, debug bool) *OpenAPI {
	return &OpenAPI{engine: engine, debug: debug}
}

func (o *OpenAPI) Spec() map[string]any {
	spec := map[string]any{
		"openapi": "3.0.3",
		"info": map[string]any{
			"title":       "restxlsx",
			"description": "RESTful API over Excel tables. Supports REST CRUD, GraphQL, SQL, and DDL.",
			"version":     "0.2.0",
		},
		"paths": o.buildPaths(),
	}

	if o.debug {
		spec["servers"] = []map[string]any{
			{"url": "http://localhost:3000", "description": "Local dev"},
		}
	}

	return spec
}

func (o *OpenAPI) buildPaths() map[string]any {
	paths := make(map[string]any)

	paths["/api/tables"] = map[string]any{
		"get": map[string]any{
			"summary":     "List all tables",
			"operationId": "listTables",
			"responses": map[string]any{
				"200": map[string]any{
					"description": "List of table names",
					"content": map[string]any{
						"application/json": map[string]any{
							"schema": map[string]any{
								"type": "object",
								"properties": map[string]any{
									"tables": map[string]any{
										"type": "array",
										"items": map[string]any{
											"type": "string",
										},
									},
								},
							},
						},
					},
				},
			},
		},
	}

	for _, name := range o.engine.ListTables() {
		t := o.engine.GetTable(name)
		tablePath := fmt.Sprintf("/api/%s", name)
		itemPath := fmt.Sprintf("/api/%s/{id}", name)

		schema := tableSchema(t)

		paths[tablePath] = map[string]any{
			"get": map[string]any{
				"summary":     fmt.Sprintf("List all %s", name),
				"operationId": fmt.Sprintf("list%s", name),
				"responses": map[string]any{
					"200": map[string]any{
						"description": fmt.Sprintf("Array of %s", name),
						"content": map[string]any{
							"application/json": map[string]any{
								"schema": map[string]any{
									"type":  "array",
									"items": schema,
								},
							},
						},
					},
				},
			},
			"post": map[string]any{
				"summary":     fmt.Sprintf("Create a new %s", name),
				"operationId": fmt.Sprintf("create%s", name),
				"requestBody": map[string]any{
					"required": true,
					"content": map[string]any{
						"application/json": map[string]any{
							"schema": schema,
						},
					},
				},
				"responses": map[string]any{
					"201": map[string]any{
						"description": "Created",
						"content": map[string]any{
							"application/json": map[string]any{
								"schema": schema,
							},
						},
					},
				},
			},
		}

		paths[itemPath] = map[string]any{
			"get": map[string]any{
				"summary":     fmt.Sprintf("Get %s by ID", name),
				"operationId": fmt.Sprintf("get%s", name),
				"parameters": []map[string]any{
					{"name": "id", "in": "path", "required": true, "schema": map[string]any{"type": "string"}},
				},
				"responses": map[string]any{
					"200": map[string]any{
						"description": fmt.Sprintf("A single %s", name),
						"content": map[string]any{
							"application/json": map[string]any{
								"schema": schema,
							},
						},
					},
					"404": map[string]any{"description": "Not found"},
				},
			},
			"put": map[string]any{
				"summary":     fmt.Sprintf("Update %s by ID", name),
				"operationId": fmt.Sprintf("update%s", name),
				"parameters": []map[string]any{
					{"name": "id", "in": "path", "required": true, "schema": map[string]any{"type": "string"}},
				},
				"requestBody": map[string]any{
					"required": true,
					"content": map[string]any{
						"application/json": map[string]any{
							"schema": schema,
						},
					},
				},
				"responses": map[string]any{
					"200": map[string]any{"description": "Updated"},
					"404": map[string]any{"description": "Not found"},
				},
			},
			"delete": map[string]any{
				"summary":     fmt.Sprintf("Delete %s by ID", name),
				"operationId": fmt.Sprintf("delete%s", name),
				"parameters": []map[string]any{
					{"name": "id", "in": "path", "required": true, "schema": map[string]any{"type": "string"}},
				},
				"responses": map[string]any{
					"204": map[string]any{"description": "Deleted"},
					"404": map[string]any{"description": "Not found"},
				},
			},
		}
	}

	paths["/api/sql"] = map[string]any{
		"post": map[string]any{
			"summary":     "Execute a SQL query",
			"operationId": "execSQL",
			"requestBody": map[string]any{
				"required": true,
				"content": map[string]any{
					"application/json": map[string]any{
						"schema": map[string]any{
							"type": "object",
							"properties": map[string]any{
								"query": map[string]any{"type": "string"},
							},
						},
					},
				},
			},
			"responses": map[string]any{
				"200": map[string]any{"description": "Query result"},
				"400": map[string]any{"description": "Bad request"},
				"403": map[string]any{"description": "Forbidden"},
			},
		},
	}

	paths["/api/ddl/sheets"] = map[string]any{
		"post": map[string]any{
			"summary":     "Create a new sheet",
			"operationId": "createSheet",
			"requestBody": map[string]any{
				"required": true,
				"content": map[string]any{
					"application/json": map[string]any{
						"schema": map[string]any{
							"type": "object",
							"properties": map[string]any{
								"name": map[string]any{"type": "string"},
							},
						},
					},
				},
			},
			"responses": map[string]any{
				"201": map[string]any{"description": "Created"},
				"403": map[string]any{"description": "Forbidden"},
			},
		},
	}
	paths["/api/ddl/sheets/{sheet}"] = map[string]any{
		"delete": map[string]any{
			"summary":     "Delete a sheet",
			"operationId": "deleteSheet",
			"parameters": []map[string]any{
				{"name": "sheet", "in": "path", "required": true, "schema": map[string]any{"type": "string"}},
			},
			"responses": map[string]any{
				"200": map[string]any{"description": "Deleted"},
				"403": map[string]any{"description": "Forbidden"},
				"404": map[string]any{"description": "Not found"},
			},
		},
	}
	paths["/api/ddl/tables"] = map[string]any{
		"post": map[string]any{
			"summary":     "Create a table on a sheet",
			"operationId": "createTable",
			"requestBody": map[string]any{
				"required": true,
				"content": map[string]any{
					"application/json": map[string]any{
						"schema": map[string]any{
							"type": "object",
							"properties": map[string]any{
								"sheet":   map[string]any{"type": "string"},
								"name":    map[string]any{"type": "string"},
								"columns": map[string]any{"type": "array", "items": map[string]any{"type": "string"}},
							},
						},
					},
				},
			},
			"responses": map[string]any{
				"201": map[string]any{"description": "Created"},
				"403": map[string]any{"description": "Forbidden"},
			},
		},
	}
	paths["/api/ddl/tables/{table}"] = map[string]any{
		"delete": map[string]any{
			"summary":     "Drop a table",
			"operationId": "deleteTable",
			"parameters": []map[string]any{
				{"name": "table", "in": "path", "required": true, "schema": map[string]any{"type": "string"}},
			},
			"responses": map[string]any{
				"200": map[string]any{"description": "Deleted"},
				"403": map[string]any{"description": "Forbidden"},
				"404": map[string]any{"description": "Not found"},
			},
		},
	}

	return paths
}

func tableSchema(t *excel.Table) map[string]any {
	props := make(map[string]any)
	required := make([]string, 0)

	for _, col := range t.Columns {
		props[col] = map[string]any{"type": "string"}
		required = append(required, col)
	}

	return map[string]any{
		"type":       "object",
		"properties": props,
		"required":   required,
	}
}

func (o *OpenAPI) Handler(w http.ResponseWriter, r *http.Request) {
	spec := o.Spec()
	w.Header().Set("Content-Type", "application/json")
	enc := json.NewEncoder(w)
	enc.SetIndent("", "  ")
	enc.Encode(spec)
}

func (o *OpenAPI) SwaggerHandler(w http.ResponseWriter, r *http.Request) {
	specBytes, _ := json.Marshal(o.Spec())
	specStr := strings.ReplaceAll(string(specBytes), `"`, `\"`)
	html := strings.Replace(swaggerHTML, "{{SPEC}}", specStr, 1)
	w.Header().Set("Content-Type", "text/html; charset=utf-8")
	w.Write([]byte(html))
}