package main

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

const PARAM_IDS = "ids"
const MAX_TERMS = 10

// ============================================================================
func handler(w http.ResponseWriter, r *http.Request) {
  err := r.ParseForm()
  if nil != err {
    fmt.Fprintln(w, "ERROR!", err)
    return
  }

  action := r.URL.Path[1:]

  switch(action) {
  case "info":
    handleInfo(w, r)
  case "search":
    handleSearch(w, r)
  default:
    fmt.Fprintf(w, "Unrecognized request:  %s\n", r.URL.Path[1:])
    fmt.Fprintf(w, "id: %s\n", r.FormValue("id"))
  
    fmt.Fprintln(w, "URL: ", r.URL)
    fmt.Fprintln(w, "Query: ", r.URL.Query())
  }
}

func handleInfo(w http.ResponseWriter, r *http.Request) {
  idParams := r.Form[PARAM_IDS]
  if 1 != len(idParams) {
    fmt.Fprintln(w, "ERROR!  Detected either zero or multiple ids= parameters.  Exactly one expected.")
    return 
  } 

  idParam := idParams[0]
  idStrings := strings.Split(idParam, ",")
  ids := make([]int, len(idStrings))
  for i, v := range(idStrings) {
    var err error
    ids[i], err = strconv.Atoi(v)
    if nil != err {
      ids[i] = 0
    }
  }

  books := queryBooksByIds(ids)

  var jsonValue []byte
  var err error
  jsonValue, err = json.Marshal(books)
  if nil != err {
    fmt.Fprintln(w, "ERROR!", err)
  } else {
    w.Write(jsonValue)
  }
}

func handleSearch(w http.ResponseWriter, r *http.Request) {
  fields := []Field{Author, Title, Series}

  terms := make([]SearchTerm, len(fields))
  
  count := 0
  for _, fv := range(fields) {
    paramName := fv.String()
    paramValues := r.Form[paramName]
    for _, pv := range(paramValues) {
      if count >= len(terms) {
        fmt.Printf("WARNING:  limit of %v search terms exceeded.  One or more terms ignored.")
        break
      }
      terms[count] = SearchTerm{Attribute:fv, Text:pv}
      count++
    }
  }

  terms = terms[:count]

  ids := queryIds(terms)

  jsonValue, err := json.Marshal(ids)
  if nil != err {
    fmt.Fprintln(w, "ERROR!", err)
  } else {
    w.Write(jsonValue)
  }
}