/*
Copyright 2012 Google Inc.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

     http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/

package serverconfig

import (
	"errors"
	"fmt"
	"net/url"
	"os"
	"path/filepath"
	"strings"

	"camlistore.org/pkg/blob"
	"camlistore.org/pkg/jsonconfig"
	"camlistore.org/pkg/jsonsign"
)

const (
	DefaultTLSCert = "config/selfgen_pem.crt"
	DefaultTLSKey  = "config/selfgen_pem.key"
)

// various parameters derived from the high-level user config
// and needed to set up the low-level config.
type configPrefixesParams struct {
	secretRing       string
	keyId            string
	indexerPath      string
	blobPath         string
	searchOwner      blob.Ref
	shareHandlerPath string
}

var tempDir = os.TempDir

func addPublishedConfig(prefixes jsonconfig.Obj,
	published jsonconfig.Obj,
	sourceRoot string) ([]interface{}, error) {
	pubPrefixes := []interface{}{}
	for k, v := range published {
		p, ok := v.(map[string]interface{})
		if !ok {
			return nil, fmt.Errorf("Wrong type for %s; was expecting map[string]interface{}, got %T", k, v)
		}
		rootName := strings.Replace(k, "/", "", -1) + "Root"
		rootPermanode, template, style := "", "", ""
		for pk, pv := range p {
			val, ok := pv.(string)
			if !ok {
				return nil, fmt.Errorf("Was expecting type string for %s, got %T", pk, pv)
			}
			switch pk {
			case "rootPermanode":
				rootPermanode = val
			case "template":
				template = val
			case "style":
				style = val
			default:
				return nil, fmt.Errorf("Unexpected key %q in config for %s", pk, k)
			}
		}
		if rootPermanode == "" || template == "" {
			return nil, fmt.Errorf("Missing key in configuration for %s, need \"rootPermanode\" and \"template\"", k)
		}
		ob := map[string]interface{}{}
		ob["handler"] = "publish"
		handlerArgs := map[string]interface{}{
			"rootName":      rootName,
			"blobRoot":      "/bs-and-maybe-also-index/",
			"searchRoot":    "/my-search/",
			"cache":         "/cache/",
			"rootPermanode": []interface{}{"/sighelper/", rootPermanode},
		}
		if sourceRoot != "" {
			handlerArgs["sourceRoot"] = sourceRoot
		}
		switch template {
		case "gallery":
			if style == "" {
				style = "pics.css"
			}
			handlerArgs["css"] = []interface{}{style}
			handlerArgs["js"] = []interface{}{"pics.js"}
			handlerArgs["scaledImage"] = "lrucache"
		case "blog":
			if style != "" {
				handlerArgs["css"] = []interface{}{style}
			}
		}
		ob["handlerArgs"] = handlerArgs
		prefixes[k] = ob
		pubPrefixes = append(pubPrefixes, k)
	}
	return pubPrefixes, nil
}

func addUIConfig(prefixes jsonconfig.Obj,
	uiPrefix string,
	published []interface{},
	sourceRoot string) {
	ob := map[string]interface{}{}
	ob["handler"] = "ui"
	handlerArgs := map[string]interface{}{
		"jsonSignRoot": "/sighelper/",
		"cache":        "/cache/",
		"scaledImage":  "lrucache",
	}
	if len(published) > 0 {
		handlerArgs["publishRoots"] = published
	}
	if sourceRoot != "" {
		handlerArgs["sourceRoot"] = sourceRoot
	}
	ob["handlerArgs"] = handlerArgs
	prefixes[uiPrefix] = ob
}

func addMongoConfig(prefixes jsonconfig.Obj, dbname string, dbinfo string) {
	fields := strings.Split(dbinfo, "@")
	if len(fields) != 2 {
		exitFailure("Malformed mongo config string. Got \"%v\", want: \"user:password@host\"", dbinfo)
	}
	host := fields[1]
	fields = strings.Split(fields[0], ":")
	if len(fields) != 2 {
		exitFailure("Malformed mongo config string. Got \"%v\", want: \"user:password\"", fields[0])
	}
	ob := map[string]interface{}{}
	ob["enabled"] = true
	ob["handler"] = "storage-mongodbindexer"
	ob["handlerArgs"] = map[string]interface{}{
		"host":       host,
		"user":       fields[0],
		"password":   fields[1],
		"database":   dbname,
		"blobSource": "/bs/",
	}
	prefixes["/index-mongo/"] = ob
}

func addSQLConfig(rdbms string, prefixes jsonconfig.Obj, dbname string, dbinfo string) {
	fields := strings.Split(dbinfo, "@")
	if len(fields) != 2 {
		exitFailure("Malformed " + rdbms + " config string. Want: \"user@host:password\"")
	}
	user := fields[0]
	fields = strings.Split(fields[1], ":")
	if len(fields) != 2 {
		exitFailure("Malformed " + rdbms + " config string. Want: \"user@host:password\"")
	}
	ob := map[string]interface{}{}
	ob["enabled"] = true
	ob["handler"] = "storage-" + rdbms + "indexer"
	ob["handlerArgs"] = map[string]interface{}{
		"host":       fields[0],
		"user":       user,
		"password":   fields[1],
		"database":   dbname,
		"blobSource": "/bs/",
	}
	prefixes["/index-"+rdbms+"/"] = ob
}

func addPostgresConfig(prefixes jsonconfig.Obj, dbname string, dbinfo string) {
	addSQLConfig("postgres", prefixes, dbname, dbinfo)
}

func addMySQLConfig(prefixes jsonconfig.Obj, dbname string, dbinfo string) {
	addSQLConfig("mysql", prefixes, dbname, dbinfo)
}

func addMemindexConfig(prefixes jsonconfig.Obj) {
	ob := map[string]interface{}{}
	ob["handler"] = "storage-memory-only-dev-indexer"
	ob["handlerArgs"] = map[string]interface{}{
		"blobSource": "/bs/",
	}
	prefixes["/index-mem/"] = ob
}

func addSQLiteConfig(prefixes jsonconfig.Obj, file string) {
	ob := map[string]interface{}{}
	ob["handler"] = "storage-sqliteindexer"
	ob["handlerArgs"] = map[string]interface{}{
		"blobSource": "/bs/",
		"file":       file,
	}
	prefixes["/index-sqlite/"] = ob
}

func addS3Config(prefixes jsonconfig.Obj, s3 string) error {
	f := strings.SplitN(s3, ":", 3)
	if len(f) != 3 {
		return errors.New(`genconfig: expected "s3" field to be of form "access_key_id:secret_access_key:bucket"`)
	}
	accessKey, secret, bucket := f[0], f[1], f[2]

	isPrimary := false
	if _, ok := prefixes["/bs/"]; !ok {
		isPrimary = true
	}
	s3Prefix := ""
	if isPrimary {
		s3Prefix = "/bs/"
	} else {
		s3Prefix = "/sto-s3/"
	}
	prefixes[s3Prefix] = map[string]interface{}{
		"handler": "storage-s3",
		"handlerArgs": map[string]interface{}{
			"aws_access_key":        accessKey,
			"aws_secret_access_key": secret,
			"bucket":                bucket,
		},
	}
	if isPrimary {
		// TODO(mpl): s3CacheBucket
		// See http://code.google.com/p/camlistore/issues/detail?id=85
		prefixes["/cache/"] = map[string]interface{}{
			"handler": "storage-filesystem",
			"handlerArgs": map[string]interface{}{
				"path": filepath.Join(tempDir(), "camli-cache"),
			},
		}
	} else {
		prefixes["/sync-to-s3/"] = map[string]interface{}{
			"handler": "sync",
			"handlerArgs": map[string]interface{}{
				"from": "/bs/",
				"to":   s3Prefix,
			},
		}
	}
	return nil
}

func addGoogleDriveConfig(prefixes jsonconfig.Obj, highCfg string) error {
	f := strings.SplitN(highCfg, ":", 4)
	if len(f) != 4 {
		return errors.New(`genconfig: expected "googledrive" field to be of form "client_id:client_secret:refresh_token:parent_id"`)
	}
	clientId, secret, refreshToken, parentId := f[0], f[1], f[2], f[3]

	isPrimary := false
	if _, ok := prefixes["/bs/"]; !ok {
		isPrimary = true
	}

	prefix := ""
	if isPrimary {
		prefix = "/bs/"
	} else {
		prefix = "/sto-googledrive/"
	}
	prefixes[prefix] = map[string]interface{}{
		"handler": "storage-googledrive",
		"handlerArgs": map[string]interface{}{
			"parent_id": parentId,
			"auth": map[string]interface{}{
				"client_id":     clientId,
				"client_secret": secret,
				"refresh_token": refreshToken,
			},
		},
	}

	if isPrimary {
		prefixes["/cache/"] = map[string]interface{}{
			"handler": "storage-filesystem",
			"handlerArgs": map[string]interface{}{
				"path": filepath.Join(tempDir(), "camli-cache"),
			},
		}
	} else {
		prefixes["/sync-to-googledrive/"] = map[string]interface{}{
			"handler": "sync",
			"handlerArgs": map[string]interface{}{
				"from": "/bs/",
				"to":   prefix,
			},
		}
	}

	return nil
}

func addGoogleCloudStorageConfig(prefixes jsonconfig.Obj, highCfg string) error {
	f := strings.SplitN(highCfg, ":", 4)
	if len(f) != 4 {
		return errors.New(`genconfig: expected "googlecloudstorage" field to be of form "client_id:client_secret:refresh_token:bucket"`)
	}
	clientId, secret, refreshToken, bucket := f[0], f[1], f[2], f[3]

	isPrimary := false
	if _, ok := prefixes["/bs/"]; !ok {
		isPrimary = true
	}

	gsPrefix := ""
	if isPrimary {
		gsPrefix = "/bs/"
	} else {
		gsPrefix = "/sto-googlecloudstorage/"
	}

	prefixes[gsPrefix] = map[string]interface{}{
		"handler": "storage-googlecloudstorage",
		"handlerArgs": map[string]interface{}{
			"bucket": bucket,
			"auth": map[string]interface{}{
				"client_id":     clientId,
				"client_secret": secret,
				"refresh_token": refreshToken,
				// If high-level config is for the common user then fullSyncOnStart = true
				// Then the default just works.
				//"fullSyncOnStart": true,
				//"blockingFullSyncOnStart": false
			},
		},
	}

	if isPrimary {
		// TODO: cacheBucket like s3CacheBucket?
		prefixes["/cache/"] = map[string]interface{}{
			"handler": "storage-filesystem",
			"handlerArgs": map[string]interface{}{
				"path": filepath.Join(tempDir(), "camli-cache"),
			},
		}
	} else {
		prefixes["/sync-to-googlecloudstorage/"] = map[string]interface{}{
			"handler": "sync",
			"handlerArgs": map[string]interface{}{
				"from": "/bs/",
				"to":   gsPrefix,
			},
		}
	}
	return nil
}

func genLowLevelPrefixes(params *configPrefixesParams, ownerName string) (m jsonconfig.Obj) {
	m = make(jsonconfig.Obj)

	haveIndex := params.indexerPath != ""
	root := "/bs/"
	pubKeyDest := root
	if haveIndex {
		root = "/bs-and-maybe-also-index/"
		pubKeyDest = "/bs-and-index/"
	}

	rootArgs := map[string]interface{}{
		"stealth":    false,
		"blobRoot":   root,
		"statusRoot": "/status/",
	}
	if ownerName != "" {
		rootArgs["ownerName"] = ownerName
	}
	m["/"] = map[string]interface{}{
		"handler":     "root",
		"handlerArgs": rootArgs,
	}
	if haveIndex {
		setMap(m, "/", "handlerArgs", "searchRoot", "/my-search/")
	}

	m["/setup/"] = map[string]interface{}{
		"handler": "setup",
	}

	m["/status/"] = map[string]interface{}{
		"handler": "status",
	}

	if params.shareHandlerPath != "" {
		m[params.shareHandlerPath] = map[string]interface{}{
			"handler": "share",
			"handlerArgs": map[string]interface{}{
				"blobRoot": "/bs/",
			},
		}
	}

	m["/sighelper/"] = map[string]interface{}{
		"handler": "jsonsign",
		"handlerArgs": map[string]interface{}{
			"secretRing":    params.secretRing,
			"keyId":         params.keyId,
			"publicKeyDest": pubKeyDest,
		},
	}

	if params.blobPath != "" {
		m["/bs/"] = map[string]interface{}{
			"handler": "storage-filesystem",
			"handlerArgs": map[string]interface{}{
				"path": params.blobPath,
			},
		}

		m["/cache/"] = map[string]interface{}{
			"handler": "storage-filesystem",
			"handlerArgs": map[string]interface{}{
				"path": filepath.Join(params.blobPath, "/cache"),
			},
		}
	}

	if haveIndex {
		m["/sync/"] = map[string]interface{}{
			"handler": "sync",
			"handlerArgs": map[string]interface{}{
				"from": "/bs/",
				"to":   params.indexerPath,
			},
		}

		m["/bs-and-index/"] = map[string]interface{}{
			"handler": "storage-replica",
			"handlerArgs": map[string]interface{}{
				"backends": []interface{}{"/bs/", params.indexerPath},
			},
		}

		m["/bs-and-maybe-also-index/"] = map[string]interface{}{
			"handler": "storage-cond",
			"handlerArgs": map[string]interface{}{
				"write": map[string]interface{}{
					"if":   "isSchema",
					"then": "/bs-and-index/",
					"else": "/bs/",
				},
				"read": "/bs/",
			},
		}

		m["/my-search/"] = map[string]interface{}{
			"handler": "search",
			"handlerArgs": map[string]interface{}{
				"index": params.indexerPath,
				"owner": params.searchOwner.String(),
			},
		}
	}

	return
}

// genLowLevelConfig returns a low-level config from a high-level config.
func genLowLevelConfig(conf *Config) (lowLevelConf *Config, err error) {
	var (
		baseURL    = conf.OptionalString("baseURL", "")
		listen     = conf.OptionalString("listen", "")
		auth       = conf.RequiredString("auth")
		keyId      = conf.RequiredString("identity")
		secretRing = conf.RequiredString("identitySecretRing")
		tlsOn      = conf.OptionalBool("https", false)
		tlsCert    = conf.OptionalString("HTTPSCertFile", "")
		tlsKey     = conf.OptionalString("HTTPSKeyFile", "")

		// Blob storage options
		blobPath           = conf.OptionalString("blobPath", "")
		s3                 = conf.OptionalString("s3", "")                 // "access_key_id:secret_access_key:bucket"
		googlecloudstorage = conf.OptionalString("googlecloudstorage", "") // "clientId:clientSecret:refreshToken:bucket"
		googledrive        = conf.OptionalString("googledrive", "")        // "clientId:clientSecret:refreshToken:parentId"
		// Enable the share handler. If true, and shareHandlerPath is empty,
		// then shareHandlerPath defaults to "/share/".
		shareHandler = conf.OptionalBool("shareHandler", false)
		// URL prefix for the share handler. If set, overrides shareHandler.
		shareHandlerPath = conf.OptionalString("shareHandlerPath", "")

		// Index options
		runIndex   = conf.OptionalBool("runIndex", true) // if false: no search, no UI, etc.
		dbname     = conf.OptionalString("dbname", "")   // for mysql, postgres, mongo
		mysql      = conf.OptionalString("mysql", "")
		postgres   = conf.OptionalString("postgres", "")
		memIndex   = conf.OptionalBool("memIndex", false)
		mongo      = conf.OptionalString("mongo", "")
		sqliteFile = conf.OptionalString("sqlite", "")

		_       = conf.OptionalList("replicateTo")
		publish = conf.OptionalObject("publish")
		// alternative source tree, to override the embedded ui and/or closure resources.
		// If non empty, the ui files will be expected at
		// sourceRoot + "/server/camlistored/ui" and the closure library at
		// sourceRoot + "/third_party/closure/lib"
		// Also used by the publish handler.
		sourceRoot = conf.OptionalString("sourceRoot", "")

		ownerName = conf.OptionalString("ownerName", "")
	)
	if err := conf.Validate(); err != nil {
		return nil, err
	}

	obj := jsonconfig.Obj{}
	if tlsOn {
		if (tlsCert != "") != (tlsKey != "") {
			return nil, errors.New("Must set both TLSCertFile and TLSKeyFile (or neither to generate a self-signed cert)")
		}
		if tlsCert != "" {
			obj["TLSCertFile"] = tlsCert
			obj["TLSKeyFile"] = tlsKey
		} else {
			obj["TLSCertFile"] = DefaultTLSCert
			obj["TLSKeyFile"] = DefaultTLSKey
		}
	}

	if baseURL != "" {
		obj["baseURL"] = strings.TrimSuffix(baseURL, "/")
		u, err := url.Parse(baseURL)
		if err != nil {
			return nil, fmt.Errorf("Error parsing baseURL %q as a URL: %v", baseURL, err)
		}
		if u.Path != "/" {
			return nil, errors.New("baseURL can't have a path, only a scheme, host, and optional port.")
		}
	}
	if listen != "" {
		obj["listen"] = listen
	}
	obj["https"] = tlsOn
	obj["auth"] = auth

	if dbname == "" {
		username := os.Getenv("USER")
		if username == "" {
			return nil, fmt.Errorf("USER env var not set; needed to define dbname")
		}
		dbname = "camli" + username
	}

	var indexerPath string
	numIndexers := numSet(mongo, mysql, postgres, sqliteFile, memIndex)
	switch {
	case runIndex && numIndexers == 0:
		return nil, fmt.Errorf("Unless wantIndex is set to false, you must specify an index option (mongo, mysql, postgres, sqlite, memIndex).")
	case runIndex && numIndexers != 1:
		return nil, fmt.Errorf("With wantIndex set true, you can only pick exactly one indexer (mongo, mysql, postgres, sqlite, memIndex).")
	case !runIndex && numIndexers != 0:
		return nil, fmt.Errorf("With wantIndex disabled, you can't specify any of mongo, mysql, postgres, sqlite, memIndex.")
	case mysql != "":
		indexerPath = "/index-mysql/"
	case postgres != "":
		indexerPath = "/index-postgres/"
	case mongo != "":
		indexerPath = "/index-mongo/"
	case sqliteFile != "":
		indexerPath = "/index-sqlite/"
	case memIndex:
		indexerPath = "/index-mem/"
	}

	entity, err := jsonsign.EntityFromSecring(keyId, secretRing)
	if err != nil {
		return nil, err
	}
	armoredPublicKey, err := jsonsign.ArmoredPublicKey(entity)
	if err != nil {
		return nil, err
	}

	nolocaldisk := blobPath == ""
	if nolocaldisk && s3 == "" && googlecloudstorage == "" {
		return nil, errors.New("You need at least one of blobPath (for localdisk) or s3 or googlecloudstorage configured for a blobserver.")
	}

	if shareHandler && shareHandlerPath == "" {
		shareHandlerPath = "/share/"
	}

	prefixesParams := &configPrefixesParams{
		secretRing:       secretRing,
		keyId:            keyId,
		indexerPath:      indexerPath,
		blobPath:         blobPath,
		searchOwner:      blob.SHA1FromString(armoredPublicKey),
		shareHandlerPath: shareHandlerPath,
	}

	prefixes := genLowLevelPrefixes(prefixesParams, ownerName)
	var cacheDir string
	if nolocaldisk {
		// Whether camlistored is run from EC2 or not, we use
		// a temp dir as the cache when primary storage is S3.
		// TODO(mpl): s3CacheBucket
		// See http://code.google.com/p/camlistore/issues/detail?id=85
		cacheDir = filepath.Join(tempDir(), "camli-cache")
	} else {
		cacheDir = filepath.Join(blobPath, "/cache")
	}
	if err := os.MkdirAll(cacheDir, 0700); err != nil {
		return nil, fmt.Errorf("Could not create blobs cache dir %s: %v", cacheDir, err)
	}

	published := []interface{}{}
	if len(publish) > 0 {
		if !runIndex {
			return nil, fmt.Errorf("publishing requires an index")
		}
		published, err = addPublishedConfig(prefixes, publish, sourceRoot)
		if err != nil {
			return nil, fmt.Errorf("Could not generate config for published: %v", err)
		}
	}

	if runIndex {
		addUIConfig(prefixes, "/ui/", published, sourceRoot)
	}

	if mysql != "" {
		addMySQLConfig(prefixes, dbname, mysql)
	}
	if postgres != "" {
		addPostgresConfig(prefixes, dbname, postgres)
	}
	if mongo != "" {
		addMongoConfig(prefixes, dbname, mongo)
	}
	if sqliteFile != "" {
		addSQLiteConfig(prefixes, sqliteFile)
	}
	if s3 != "" {
		if err := addS3Config(prefixes, s3); err != nil {
			return nil, err
		}
	}
	if googledrive != "" {
		if err := addGoogleDriveConfig(prefixes, googledrive); err != nil {
			return nil, err
		}
	}
	if googlecloudstorage != "" {
		if err := addGoogleCloudStorageConfig(prefixes, googlecloudstorage); err != nil {
			return nil, err
		}
	}
	if indexerPath == "/index-mem/" {
		addMemindexConfig(prefixes)
	}

	obj["prefixes"] = (map[string]interface{})(prefixes)

	lowLevelConf = &Config{
		Obj:        obj,
		configPath: conf.configPath,
	}
	return lowLevelConf, nil
}

func numSet(vv ...interface{}) (num int) {
	for _, vi := range vv {
		switch v := vi.(type) {
		case string:
			if v != "" {
				num++
			}
		case bool:
			if v {
				num++
			}
		default:
			panic("unknown type")
		}
	}
	return
}

func setMap(m map[string]interface{}, v ...interface{}) {
	if len(v) < 2 {
		panic("too few args")
	}
	if len(v) == 2 {
		m[v[0].(string)] = v[1]
		return
	}
	setMap(m[v[0].(string)].(map[string]interface{}), v[1:]...)
}