package coderd

import (
	"context"
	"fmt"
	"net/http"
	"strconv"
	"time"

	"github.com/go-chi/chi/v5"
	"github.com/google/uuid"
	"golang.org/x/xerrors"

	"cdr.dev/slog/v3"
	"github.com/coder/coder/v2/coderd/apikey"
	"github.com/coder/coder/v2/coderd/audit"
	"github.com/coder/coder/v2/coderd/database"
	"github.com/coder/coder/v2/coderd/database/dbtime"
	"github.com/coder/coder/v2/coderd/httpapi"
	"github.com/coder/coder/v2/coderd/httpmw"
	"github.com/coder/coder/v2/coderd/rbac"
	"github.com/coder/coder/v2/coderd/rbac/policy"
	"github.com/coder/coder/v2/coderd/telemetry"
	"github.com/coder/coder/v2/coderd/util/namesgenerator"
	"github.com/coder/coder/v2/codersdk"
)

// Creates a new token API key with the given scope and lifetime.
//
// @Summary Create token API key
// @ID create-token-api-key
// @Security CoderSessionToken
// @Accept json
// @Produce json
// @Tags Users
// @Param user path string true "User ID, name, or me"
// @Param request body codersdk.CreateTokenRequest true "Create token request"
// @Success 201 {object} codersdk.GenerateAPIKeyResponse
// @Router /api/v2/users/{user}/keys/tokens [post]
func (api *API) postToken(rw http.ResponseWriter, r *http.Request) {
	var (
		ctx               = r.Context()
		user              = httpmw.UserParam(r)
		auditor           = api.Auditor.Load()
		aReq, commitAudit = audit.InitRequest[database.APIKey](rw, &audit.RequestParams{
			Audit:   *auditor,
			Log:     api.Logger,
			Request: r,
			Action:  database.AuditActionCreate,
		})
	)
	aReq.Old = database.APIKey{}
	defer commitAudit()

	var createToken codersdk.CreateTokenRequest
	if !httpapi.Read(ctx, rw, r, &createToken) {
		return
	}

	// TODO(Cian): System users technically just have the 'member' role
	// and we don't want to disallow all members from creating API keys.
	if user.IsSystem {
		api.Logger.Warn(ctx, "disallowed creating api key for system user", slog.F("user_id", user.ID))
		httpapi.Forbidden(rw)
		return
	}

	// Map and validate requested scope.
	// Accept legacy special scopes (all, application_connect) and external scopes.
	// Default to coder:all scopes for backward compatibility.
	scopes := database.APIKeyScopes{database.ApiKeyScopeCoderAll}
	if len(createToken.Scopes) > 0 {
		scopes = make(database.APIKeyScopes, 0, len(createToken.Scopes))
		for _, s := range createToken.Scopes {
			name := string(s)
			if !rbac.IsExternalScope(rbac.ScopeName(name)) {
				httpapi.Write(ctx, rw, http.StatusBadRequest, codersdk.Response{
					Message: "Failed to create API key.",
					Detail:  fmt.Sprintf("invalid or unsupported API key scope: %q", name),
				})
				return
			}
			scopes = append(scopes, database.APIKeyScope(name))
		}
	} else if string(createToken.Scope) != "" {
		name := string(createToken.Scope)
		if !rbac.IsExternalScope(rbac.ScopeName(name)) {
			httpapi.Write(ctx, rw, http.StatusBadRequest, codersdk.Response{
				Message: "Failed to create API key.",
				Detail:  fmt.Sprintf("invalid or unsupported API key scope: %q", name),
			})
			return
		}
		switch name {
		case "all":
			scopes = database.APIKeyScopes{database.ApiKeyScopeCoderAll}
		case "application_connect":
			scopes = database.APIKeyScopes{database.ApiKeyScopeCoderApplicationConnect}
		default:
			scopes = database.APIKeyScopes{database.APIKeyScope(name)}
		}
	}

	tokenName := namesgenerator.NameDigitWith("_")

	if len(createToken.TokenName) != 0 {
		tokenName = createToken.TokenName
	}

	params := apikey.CreateParams{
		UserID:          user.ID,
		LoginType:       database.LoginTypeToken,
		DefaultLifetime: api.DeploymentValues.Sessions.DefaultTokenDuration.Value(),
		Scopes:          scopes,
		TokenName:       tokenName,
	}

	if len(createToken.AllowList) > 0 {
		rbacAllowListElements := make([]rbac.AllowListElement, 0, len(createToken.AllowList))
		for _, t := range createToken.AllowList {
			entry, err := rbac.NewAllowListElement(string(t.Type), t.ID)
			if err != nil {
				httpapi.Write(ctx, rw, http.StatusBadRequest, codersdk.Response{
					Message: "Failed to create API key.",
					Detail:  err.Error(),
				})
				return
			}
			rbacAllowListElements = append(rbacAllowListElements, entry)
		}

		rbacAllowList, err := rbac.NormalizeAllowList(rbacAllowListElements)
		if err != nil {
			httpapi.Write(ctx, rw, http.StatusBadRequest, codersdk.Response{
				Message: "Failed to create API key.",
				Detail:  err.Error(),
			})
			return
		}

		dbAllowList := make(database.AllowList, 0, len(rbacAllowList))
		for _, e := range rbacAllowList {
			dbAllowList = append(dbAllowList, rbac.AllowListElement{Type: e.Type, ID: e.ID})
		}

		params.AllowList = dbAllowList
	}

	if createToken.Lifetime != 0 {
		err := api.validateAPIKeyLifetime(ctx, user.ID, createToken.Lifetime)
		if err != nil {
			httpapi.Write(ctx, rw, http.StatusBadRequest, codersdk.Response{
				Message: "Failed to validate create API key request.",
				Detail:  err.Error(),
			})
			return
		}
		params.ExpiresAt = dbtime.Now().Add(createToken.Lifetime)
		params.LifetimeSeconds = int64(createToken.Lifetime.Seconds())
	}

	cookie, key, err := api.createAPIKey(ctx, params)
	if err != nil {
		if database.IsUniqueViolation(err, database.UniqueIndexAPIKeyName) {
			httpapi.Write(ctx, rw, http.StatusConflict, codersdk.Response{
				Message: fmt.Sprintf("A token with name %q already exists.", tokenName),
				Validations: []codersdk.ValidationError{{
					Field:  "name",
					Detail: "This value is already in use and should be unique.",
				}},
			})
			return
		}
		httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
			Message: "Failed to create API key.",
			Detail:  err.Error(),
		})
		return
	}
	aReq.New = *key
	httpapi.Write(ctx, rw, http.StatusCreated, codersdk.GenerateAPIKeyResponse{Key: cookie.Value})
}

// Creates a new session key, used for logging in via the CLI.
//
// @Summary Create new session key
// @ID create-new-session-key
// @Security CoderSessionToken
// @Produce json
// @Tags Users
// @Param user path string true "User ID, name, or me"
// @Success 201 {object} codersdk.GenerateAPIKeyResponse
// @Router /api/v2/users/{user}/keys [post]
func (api *API) postAPIKey(rw http.ResponseWriter, r *http.Request) {
	var (
		ctx               = r.Context()
		user              = httpmw.UserParam(r)
		auditor           = api.Auditor.Load()
		aReq, commitAudit = audit.InitRequest[database.APIKey](rw, &audit.RequestParams{
			Audit:   *auditor,
			Log:     api.Logger,
			Request: r,
			Action:  database.AuditActionCreate,
		})
	)
	aReq.Old = database.APIKey{}
	defer commitAudit()

	// TODO(Cian): System users technically just have the 'member' role
	// and we don't want to disallow all members from creating API keys.
	if user.IsSystem {
		api.Logger.Warn(ctx, "disallowed creating api key for system user", slog.F("user_id", user.ID))
		httpapi.Forbidden(rw)
		return
	}

	cookie, key, err := api.createAPIKey(ctx, apikey.CreateParams{
		UserID:          user.ID,
		DefaultLifetime: api.DeploymentValues.Sessions.DefaultTokenDuration.Value(),
		LoginType:       database.LoginTypePassword,
		RemoteAddr:      r.RemoteAddr,
	})
	if err != nil {
		httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
			Message: "Failed to create API key.",
			Detail:  err.Error(),
		})
		return
	}

	aReq.New = *key
	// We intentionally do not set the cookie on the response here.
	// Setting the cookie will couple the browser session to the API
	// key we return here, meaning logging out of the website would
	// invalid your CLI key.
	httpapi.Write(ctx, rw, http.StatusCreated, codersdk.GenerateAPIKeyResponse{Key: cookie.Value})
}

// @Summary Get API key by ID
// @ID get-api-key-by-id
// @Security CoderSessionToken
// @Produce json
// @Tags Users
// @Param user path string true "User ID, name, or me"
// @Param keyid path string true "Key ID" format(string)
// @Success 200 {object} codersdk.APIKey
// @Router /api/v2/users/{user}/keys/{keyid} [get]
func (api *API) apiKeyByID(rw http.ResponseWriter, r *http.Request) {
	ctx := r.Context()

	keyID := chi.URLParam(r, "keyid")
	key, err := api.Database.GetAPIKeyByID(ctx, keyID)
	if httpapi.Is404Error(err) {
		httpapi.ResourceNotFound(rw)
		return
	}
	if err != nil {
		httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
			Message: "Internal error fetching API key.",
			Detail:  err.Error(),
		})
		return
	}

	httpapi.Write(ctx, rw, http.StatusOK, convertAPIKey(key))
}

// @Summary Get API key by token name
// @ID get-api-key-by-token-name
// @Security CoderSessionToken
// @Produce json
// @Tags Users
// @Param user path string true "User ID, name, or me"
// @Param keyname path string true "Key Name" format(string)
// @Success 200 {object} codersdk.APIKey
// @Router /api/v2/users/{user}/keys/tokens/{keyname} [get]
func (api *API) apiKeyByName(rw http.ResponseWriter, r *http.Request) {
	var (
		ctx       = r.Context()
		user      = httpmw.UserParam(r)
		tokenName = chi.URLParam(r, "keyname")
	)

	token, err := api.Database.GetAPIKeyByName(ctx, database.GetAPIKeyByNameParams{
		TokenName: tokenName,
		UserID:    user.ID,
	})
	if httpapi.Is404Error(err) {
		httpapi.ResourceNotFound(rw)
		return
	}
	if err != nil {
		httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
			Message: "Internal error fetching API key.",
			Detail:  err.Error(),
		})
		return
	}

	httpapi.Write(ctx, rw, http.StatusOK, convertAPIKey(token))
}

// @Summary Get user tokens
// @ID get-user-tokens
// @Security CoderSessionToken
// @Produce json
// @Tags Users
// @Param user path string true "User ID, name, or me"
// @Success 200 {array} codersdk.APIKey
// @Param include_expired query bool false "Include expired tokens in the list"
// @Router /api/v2/users/{user}/keys/tokens [get]
func (api *API) tokens(rw http.ResponseWriter, r *http.Request) {
	var (
		ctx               = r.Context()
		user              = httpmw.UserParam(r)
		keys              []database.APIKey
		err               error
		queryStr          = r.URL.Query().Get("include_all")
		includeAll, _     = strconv.ParseBool(queryStr)
		expiredStr        = r.URL.Query().Get("include_expired")
		includeExpired, _ = strconv.ParseBool(expiredStr)
	)

	if includeAll {
		// get tokens for all users
		keys, err = api.Database.GetAPIKeysByLoginType(ctx, database.GetAPIKeysByLoginTypeParams{
			LoginType:      database.LoginTypeToken,
			IncludeExpired: includeExpired,
		})
		if err != nil {
			httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
				Message: "Internal error fetching API keys.",
				Detail:  err.Error(),
			})
			return
		}
	} else {
		// get user's tokens only
		keys, err = api.Database.GetAPIKeysByUserID(ctx, database.GetAPIKeysByUserIDParams{LoginType: database.LoginTypeToken, UserID: user.ID, IncludeExpired: includeExpired})
		if err != nil {
			httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
				Message: "Internal error fetching API keys.",
				Detail:  err.Error(),
			})
			return
		}
	}

	keys, err = AuthorizeFilter(api.HTTPAuth, r, policy.ActionRead, keys)
	if err != nil {
		httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
			Message: "Internal error fetching keys.",
			Detail:  err.Error(),
		})
		return
	}

	var userIDs []uuid.UUID
	for _, key := range keys {
		userIDs = append(userIDs, key.UserID)
	}

	users, _ := api.Database.GetUsersByIDs(ctx, userIDs)
	usersByID := map[uuid.UUID]database.User{}
	for _, user := range users {
		usersByID[user.ID] = user
	}

	var apiKeys []codersdk.APIKeyWithOwner
	for _, key := range keys {
		if user, exists := usersByID[key.UserID]; exists {
			apiKeys = append(apiKeys, codersdk.APIKeyWithOwner{
				APIKey:   convertAPIKey(key),
				Username: user.Username,
			})
		} else {
			apiKeys = append(apiKeys, codersdk.APIKeyWithOwner{
				APIKey:   convertAPIKey(key),
				Username: "",
			})
		}
	}

	httpapi.Write(ctx, rw, http.StatusOK, apiKeys)
}

// @Summary Delete API key
// @ID delete-api-key
// @Security CoderSessionToken
// @Tags Users
// @Param user path string true "User ID, name, or me"
// @Param keyid path string true "Key ID" format(string)
// @Success 204
// @Router /api/v2/users/{user}/keys/{keyid} [delete]
func (api *API) deleteAPIKey(rw http.ResponseWriter, r *http.Request) {
	var (
		ctx               = r.Context()
		keyID             = chi.URLParam(r, "keyid")
		auditor           = api.Auditor.Load()
		aReq, commitAudit = audit.InitRequest[database.APIKey](rw, &audit.RequestParams{
			Audit:   *auditor,
			Log:     api.Logger,
			Request: r,
			Action:  database.AuditActionDelete,
		})
		key, err = api.Database.GetAPIKeyByID(ctx, keyID)
	)
	if err != nil {
		api.Logger.Warn(ctx, "get API Key for audit log")
	}
	aReq.Old = key
	defer commitAudit()

	err = api.Database.DeleteAPIKeyByID(ctx, keyID)
	if httpapi.Is404Error(err) {
		httpapi.ResourceNotFound(rw)
		return
	}
	if err != nil {
		httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
			Message: "Internal error deleting API key.",
			Detail:  err.Error(),
		})
		return
	}

	rw.WriteHeader(http.StatusNoContent)
}

// @Summary Expire API key
// @ID expire-api-key
// @Security CoderSessionToken
// @Tags Users
// @Param user path string true "User ID, name, or me"
// @Param keyid path string true "Key ID" format(string)
// @Success 204
// @Failure 404 {object} codersdk.Response
// @Failure 500 {object} codersdk.Response
// @Router /api/v2/users/{user}/keys/{keyid}/expire [put]
func (api *API) expireAPIKey(rw http.ResponseWriter, r *http.Request) {
	var (
		ctx               = r.Context()
		keyID             = chi.URLParam(r, "keyid")
		auditor           = api.Auditor.Load()
		aReq, commitAudit = audit.InitRequest[database.APIKey](rw, &audit.RequestParams{
			Audit:   *auditor,
			Log:     api.Logger,
			Request: r,
			Action:  database.AuditActionWrite,
		})
	)
	defer commitAudit()

	if err := api.Database.InTx(func(db database.Store) error {
		key, err := db.GetAPIKeyByID(ctx, keyID)
		if err != nil {
			return xerrors.Errorf("fetch API key: %w", err)
		}
		if !key.ExpiresAt.After(api.Clock.Now()) {
			return nil // Already expired
		}
		aReq.Old = key
		if err := db.UpdateAPIKeyByID(ctx, database.UpdateAPIKeyByIDParams{
			ID:        key.ID,
			LastUsed:  key.LastUsed,
			ExpiresAt: dbtime.Now(),
			IPAddress: key.IPAddress,
		}); err != nil {
			return xerrors.Errorf("expire API key: %w", err)
		}
		// Fetch the updated key for audit log.
		newKey, err := db.GetAPIKeyByID(ctx, keyID)
		if err != nil {
			api.Logger.Warn(ctx, "failed to fetch updated API key for audit log", slog.Error(err))
		} else {
			aReq.New = newKey
		}
		return nil
	}, nil); httpapi.Is404Error(err) {
		httpapi.ResourceNotFound(rw)
		return
	} else if err != nil {
		httpapi.Write(ctx, rw, http.StatusInternalServerError, codersdk.Response{
			Message: "Internal error expiring API key.",
			Detail:  err.Error(),
		})
		return
	}

	rw.WriteHeader(http.StatusNoContent)
}

// @Summary Get token config
// @ID get-token-config
// @Security CoderSessionToken
// @Produce json
// @Tags General
// @Param user path string true "User ID, name, or me"
// @Success 200 {object} codersdk.TokenConfig
// @Router /api/v2/users/{user}/keys/tokens/tokenconfig [get]
func (api *API) tokenConfig(rw http.ResponseWriter, r *http.Request) {
	user := httpmw.UserParam(r)
	maxLifetime, err := api.getMaxTokenLifetime(r.Context(), user.ID)
	if err != nil {
		httpapi.Write(r.Context(), rw, http.StatusInternalServerError, codersdk.Response{
			Message: "Failed to get token configuration.",
			Detail:  err.Error(),
		})
		return
	}

	httpapi.Write(
		r.Context(), rw, http.StatusOK,
		codersdk.TokenConfig{
			MaxTokenLifetime: maxLifetime,
		},
	)
}

func (api *API) validateAPIKeyLifetime(ctx context.Context, userID uuid.UUID, lifetime time.Duration) error {
	if lifetime <= 0 {
		return xerrors.New("lifetime must be positive number greater than 0")
	}

	maxLifetime, err := api.getMaxTokenLifetime(ctx, userID)
	if err != nil {
		return xerrors.Errorf("failed to get max token lifetime: %w", err)
	}

	if lifetime > maxLifetime {
		return xerrors.Errorf(
			"lifetime must be less than %v",
			maxLifetime,
		)
	}

	return nil
}

// getMaxTokenLifetime returns the maximum allowed token lifetime for a user.
// It distinguishes between regular users and owners.
func (api *API) getMaxTokenLifetime(ctx context.Context, userID uuid.UUID) (time.Duration, error) {
	subject, _, err := httpmw.UserRBACSubject(ctx, api.Database, userID, rbac.ScopeAll)
	if err != nil {
		return 0, xerrors.Errorf("failed to get user rbac subject: %w", err)
	}

	roles, err := subject.Roles.Expand()
	if err != nil {
		return 0, xerrors.Errorf("failed to expand user roles: %w", err)
	}

	maxLifetime := api.DeploymentValues.Sessions.MaximumTokenDuration.Value()
	for _, role := range roles {
		if role.Identifier.Name == codersdk.RoleOwner {
			// Owners have a different max lifetime.
			maxLifetime = api.DeploymentValues.Sessions.MaximumAdminTokenDuration.Value()
			break
		}
	}

	return maxLifetime, nil
}

func (api *API) createAPIKey(ctx context.Context, params apikey.CreateParams) (*http.Cookie, *database.APIKey, error) {
	key, sessionToken, err := apikey.Generate(params)
	if err != nil {
		return nil, nil, xerrors.Errorf("generate API key: %w", err)
	}

	newkey, err := api.Database.InsertAPIKey(ctx, key)
	if err != nil {
		return nil, nil, xerrors.Errorf("insert API key: %w", err)
	}

	api.Telemetry.Report(&telemetry.Snapshot{
		APIKeys: []telemetry.APIKey{telemetry.ConvertAPIKey(newkey)},
	})

	return api.DeploymentValues.HTTPCookies.Apply(&http.Cookie{
		Name:     codersdk.SessionTokenCookie,
		Value:    sessionToken,
		Path:     "/",
		HttpOnly: true,
		// MaxAge is set so the browser persists the cookie to disk rather
		// than keeping it in memory as a session cookie. Standalone PWAs
		// (display: standalone) run in their own browser process, and
		// mobile OSes kill that process when the app is swiped away —
		// deleting in-memory cookies and forcing an unexpected login.
		//
		// We use a long static value (1 year) instead of the key's
		// LifetimeSeconds because the server refreshes the key's
		// ExpiresAt on activity but does not re-set the cookie. Tying
		// MaxAge to the key lifetime would cause the cookie to expire
		// client-side even when the server-side key is still valid.
		//
		// Security is not affected: the server validates ExpiresAt on
		// every request regardless of the cookie's MaxAge.
		MaxAge: int((365 * 24 * time.Hour).Seconds()),
	}), &newkey, nil
}