package api

//go:generate go run github.com/99designs/gqlgen

import (
	"context"
	"errors"
	"fmt"
	"net/http"
	"regexp"
	"strings"

	"github.com/99designs/gqlgen/graphql"
	"github.com/oklog/ulid"
	"github.com/vektah/gqlparser/v2/gqlerror"

	"github.com/dstotijn/hetty/pkg/proj"
	"github.com/dstotijn/hetty/pkg/reqlog"
	"github.com/dstotijn/hetty/pkg/scope"
	"github.com/dstotijn/hetty/pkg/search"
	"github.com/dstotijn/hetty/pkg/sender"
)

var httpProtocolMap = map[string]HTTPProtocol{
	sender.HTTPProto1: HTTPProtocolHTTP1,
	sender.HTTPProto2: HTTPProtocolHTTP2,
}

var revHTTPProtocolMap = map[HTTPProtocol]string{
	HTTPProtocolHTTP1: sender.HTTPProto1,
	HTTPProtocolHTTP2: sender.HTTPProto2,
}

type Resolver struct {
	ProjectService    proj.Service
	RequestLogService reqlog.Service
	SenderService     sender.Service
}

type (
	queryResolver    struct{ *Resolver }
	mutationResolver struct{ *Resolver }
)

func (r *Resolver) Query() QueryResolver       { return &queryResolver{r} }
func (r *Resolver) Mutation() MutationResolver { return &mutationResolver{r} }

func (r *queryResolver) HTTPRequestLogs(ctx context.Context) ([]HTTPRequestLog, error) {
	reqs, err := r.RequestLogService.FindRequests(ctx)
	if errors.Is(err, proj.ErrNoProject) {
		return nil, noActiveProjectErr(ctx)
	} else if err != nil {
		return nil, fmt.Errorf("could not query repository for requests: %w", err)
	}

	logs := make([]HTTPRequestLog, len(reqs))

	for i, req := range reqs {
		req, err := parseRequestLog(req)
		if err != nil {
			return nil, err
		}

		logs[i] = req
	}

	return logs, nil
}

func (r *queryResolver) HTTPRequestLog(ctx context.Context, id ulid.ULID) (*HTTPRequestLog, error) {
	log, err := r.RequestLogService.FindRequestLogByID(ctx, id)
	if errors.Is(err, reqlog.ErrRequestNotFound) {
		return nil, nil
	} else if err != nil {
		return nil, fmt.Errorf("could not get request by ID: %w", err)
	}

	req, err := parseRequestLog(log)
	if err != nil {
		return nil, err
	}

	return &req, nil
}

func parseRequestLog(reqLog reqlog.RequestLog) (HTTPRequestLog, error) {
	method := HTTPMethod(reqLog.Method)
	if method != "" && !method.IsValid() {
		return HTTPRequestLog{}, fmt.Errorf("request has invalid method: %v", method)
	}

	log := HTTPRequestLog{
		ID:        reqLog.ID,
		Proto:     reqLog.Proto,
		Method:    method,
		Timestamp: ulid.Time(reqLog.ID.Time()),
	}

	if reqLog.URL != nil {
		log.URL = reqLog.URL.String()
	}

	if len(reqLog.Body) > 0 {
		bodyStr := string(reqLog.Body)
		log.Body = &bodyStr
	}

	if reqLog.Header != nil {
		log.Headers = make([]HTTPHeader, 0)

		for key, values := range reqLog.Header {
			for _, value := range values {
				log.Headers = append(log.Headers, HTTPHeader{
					Key:   key,
					Value: value,
				})
			}
		}
	}

	if reqLog.Response != nil {
		resLog, err := parseResponseLog(*reqLog.Response)
		if err != nil {
			return HTTPRequestLog{}, err
		}

		resLog.ID = reqLog.ID

		log.Response = &resLog
	}

	return log, nil
}

func parseResponseLog(resLog reqlog.ResponseLog) (HTTPResponseLog, error) {
	proto := httpProtocolMap[resLog.Proto]
	if !proto.IsValid() {
		return HTTPResponseLog{}, fmt.Errorf("sender response has invalid protocol: %v", resLog.Proto)
	}

	httpResLog := HTTPResponseLog{
		Proto:      proto,
		StatusCode: resLog.StatusCode,
	}
	statusReasonSubs := strings.SplitN(resLog.Status, " ", 2)

	if len(statusReasonSubs) == 2 {
		httpResLog.StatusReason = statusReasonSubs[1]
	}

	if len(resLog.Body) > 0 {
		bodyStr := string(resLog.Body)
		httpResLog.Body = &bodyStr
	}

	if resLog.Header != nil {
		httpResLog.Headers = make([]HTTPHeader, 0)

		for key, values := range resLog.Header {
			for _, value := range values {
				httpResLog.Headers = append(httpResLog.Headers, HTTPHeader{
					Key:   key,
					Value: value,
				})
			}
		}
	}

	return httpResLog, nil
}

func (r *mutationResolver) CreateProject(ctx context.Context, name string) (*Project, error) {
	p, err := r.ProjectService.CreateProject(ctx, name)
	if errors.Is(err, proj.ErrInvalidName) {
		return nil, gqlerror.Errorf("Project name must only contain alphanumeric or space chars.")
	} else if err != nil {
		return nil, fmt.Errorf("could not open project: %w", err)
	}

	return &Project{
		ID:       p.ID,
		Name:     p.Name,
		IsActive: r.ProjectService.IsProjectActive(p.ID),
	}, nil
}

func (r *mutationResolver) OpenProject(ctx context.Context, id ulid.ULID) (*Project, error) {
	p, err := r.ProjectService.OpenProject(ctx, id)
	if errors.Is(err, proj.ErrInvalidName) {
		return nil, gqlerror.Errorf("Project name must only contain alphanumeric or space chars.")
	} else if err != nil {
		return nil, fmt.Errorf("could not open project: %w", err)
	}

	return &Project{
		ID:       p.ID,
		Name:     p.Name,
		IsActive: r.ProjectService.IsProjectActive(p.ID),
	}, nil
}

func (r *queryResolver) ActiveProject(ctx context.Context) (*Project, error) {
	p, err := r.ProjectService.ActiveProject(ctx)
	if errors.Is(err, proj.ErrNoProject) {
		return nil, nil
	} else if err != nil {
		return nil, fmt.Errorf("could not open project: %w", err)
	}

	return &Project{
		ID:       p.ID,
		Name:     p.Name,
		IsActive: r.ProjectService.IsProjectActive(p.ID),
	}, nil
}

func (r *queryResolver) Projects(ctx context.Context) ([]Project, error) {
	p, err := r.ProjectService.Projects(ctx)
	if err != nil {
		return nil, fmt.Errorf("could not get projects: %w", err)
	}

	projects := make([]Project, len(p))
	for i, proj := range p {
		projects[i] = Project{
			ID:       proj.ID,
			Name:     proj.Name,
			IsActive: r.ProjectService.IsProjectActive(proj.ID),
		}
	}

	return projects, nil
}

func (r *queryResolver) Scope(ctx context.Context) ([]ScopeRule, error) {
	rules := r.ProjectService.Scope().Rules()
	return scopeToScopeRules(rules), nil
}

func regexpToStringPtr(r *regexp.Regexp) *string {
	if r == nil {
		return nil
	}

	s := r.String()

	return &s
}

func (r *mutationResolver) CloseProject(ctx context.Context) (*CloseProjectResult, error) {
	if err := r.ProjectService.CloseProject(); err != nil {
		return nil, fmt.Errorf("could not close project: %w", err)
	}

	return &CloseProjectResult{true}, nil
}

func (r *mutationResolver) DeleteProject(ctx context.Context, id ulid.ULID) (*DeleteProjectResult, error) {
	if err := r.ProjectService.DeleteProject(ctx, id); err != nil {
		return nil, fmt.Errorf("could not delete project: %w", err)
	}

	return &DeleteProjectResult{
		Success: true,
	}, nil
}

func (r *mutationResolver) ClearHTTPRequestLog(ctx context.Context) (*ClearHTTPRequestLogResult, error) {
	project, err := r.ProjectService.ActiveProject(ctx)
	if errors.Is(err, proj.ErrNoProject) {
		return nil, noActiveProjectErr(ctx)
	} else if err != nil {
		return nil, fmt.Errorf("could not get active project: %w", err)
	}

	if err := r.RequestLogService.ClearRequests(ctx, project.ID); err != nil {
		return nil, fmt.Errorf("could not clear request log: %w", err)
	}

	return &ClearHTTPRequestLogResult{true}, nil
}

func (r *mutationResolver) SetScope(ctx context.Context, input []ScopeRuleInput) ([]ScopeRule, error) {
	rules := make([]scope.Rule, len(input))

	for i, rule := range input {
		u, err := stringPtrToRegexp(rule.URL)
		if err != nil {
			return nil, fmt.Errorf("invalid URL in scope rule: %w", err)
		}

		var headerKey, headerValue *regexp.Regexp

		if rule.Header != nil {
			headerKey, err = stringPtrToRegexp(rule.Header.Key)
			if err != nil {
				return nil, fmt.Errorf("invalid header key in scope rule: %w", err)
			}

			headerValue, err = stringPtrToRegexp(rule.Header.Key)
			if err != nil {
				return nil, fmt.Errorf("invalid header value in scope rule: %w", err)
			}
		}

		body, err := stringPtrToRegexp(rule.Body)
		if err != nil {
			return nil, fmt.Errorf("invalid body in scope rule: %w", err)
		}

		rules[i] = scope.Rule{
			URL: u,
			Header: scope.Header{
				Key:   headerKey,
				Value: headerValue,
			},
			Body: body,
		}
	}

	err := r.ProjectService.SetScopeRules(ctx, rules)
	if err != nil {
		return nil, fmt.Errorf("could not set scope rules: %w", err)
	}

	return scopeToScopeRules(rules), nil
}

func (r *queryResolver) HTTPRequestLogFilter(ctx context.Context) (*HTTPRequestLogFilter, error) {
	return findReqFilterToHTTPReqLogFilter(r.RequestLogService.FindReqsFilter()), nil
}

func (r *mutationResolver) SetHTTPRequestLogFilter(
	ctx context.Context,
	input *HTTPRequestLogFilterInput,
) (*HTTPRequestLogFilter, error) {
	filter, err := findRequestsFilterFromInput(input)
	if err != nil {
		return nil, fmt.Errorf("could not parse request log filter: %w", err)
	}

	err = r.ProjectService.SetRequestLogFindFilter(ctx, filter)
	if errors.Is(err, proj.ErrNoProject) {
		return nil, noActiveProjectErr(ctx)
	} else if err != nil {
		return nil, fmt.Errorf("could not set request log filter: %w", err)
	}

	return findReqFilterToHTTPReqLogFilter(filter), nil
}

func (r *queryResolver) SenderRequest(ctx context.Context, id ulid.ULID) (*SenderRequest, error) {
	senderReq, err := r.SenderService.FindRequestByID(ctx, id)
	if errors.Is(err, sender.ErrRequestNotFound) {
		return nil, nil
	} else if err != nil {
		return nil, fmt.Errorf("could not get request by ID: %w", err)
	}

	req, err := parseSenderRequest(senderReq)
	if err != nil {
		return nil, err
	}

	return &req, nil
}

func (r *queryResolver) SenderRequests(ctx context.Context) ([]SenderRequest, error) {
	reqs, err := r.SenderService.FindRequests(ctx)
	if errors.Is(err, proj.ErrNoProject) {
		return nil, noActiveProjectErr(ctx)
	} else if err != nil {
		return nil, fmt.Errorf("failed to find sender requests: %w", err)
	}

	senderReqs := make([]SenderRequest, len(reqs))

	for i, req := range reqs {
		req, err := parseSenderRequest(req)
		if err != nil {
			return nil, err
		}

		senderReqs[i] = req
	}

	return senderReqs, nil
}

func (r *mutationResolver) SetSenderRequestFilter(
	ctx context.Context,
	input *SenderRequestFilterInput,
) (*SenderRequestFilter, error) {
	filter, err := findSenderRequestsFilterFromInput(input)
	if err != nil {
		return nil, fmt.Errorf("could not parse request log filter: %w", err)
	}

	err = r.ProjectService.SetSenderRequestFindFilter(ctx, filter)
	if errors.Is(err, proj.ErrNoProject) {
		return nil, noActiveProjectErr(ctx)
	} else if err != nil {
		return nil, fmt.Errorf("could not set request log filter: %w", err)
	}

	return findReqFilterToSenderReqFilter(filter), nil
}

func (r *mutationResolver) CreateOrUpdateSenderRequest(ctx context.Context, input SenderRequestInput) (*SenderRequest, error) {
	req := sender.Request{
		URL:    input.URL,
		Header: make(http.Header),
	}

	if input.ID != nil {
		req.ID = *input.ID
	}

	if input.Method != nil {
		req.Method = input.Method.String()
	}

	if input.Proto != nil {
		req.Proto = revHTTPProtocolMap[*input.Proto]
	}

	for _, header := range input.Headers {
		req.Header.Add(header.Key, header.Value)
	}

	if input.Body != nil {
		req.Body = []byte(*input.Body)
	}

	req, err := r.SenderService.CreateOrUpdateRequest(ctx, req)
	if errors.Is(err, proj.ErrNoProject) {
		return nil, noActiveProjectErr(ctx)
	} else if err != nil {
		return nil, fmt.Errorf("could not create sender request: %w", err)
	}

	senderReq, err := parseSenderRequest(req)
	if err != nil {
		return nil, err
	}

	return &senderReq, nil
}

func (r *mutationResolver) CreateSenderRequestFromHTTPRequestLog(ctx context.Context, id ulid.ULID) (*SenderRequest, error) {
	req, err := r.SenderService.CloneFromRequestLog(ctx, id)
	if errors.Is(err, proj.ErrNoProject) {
		return nil, noActiveProjectErr(ctx)
	} else if err != nil {
		return nil, fmt.Errorf("could not create sender request from http request log: %w", err)
	}

	senderReq, err := parseSenderRequest(req)
	if err != nil {
		return nil, err
	}

	return &senderReq, nil
}

func (r *mutationResolver) SendRequest(ctx context.Context, id ulid.ULID) (*SenderRequest, error) {
	// Use new context, because we don't want to risk interrupting sending the request
	// or the subsequent storing of the response, e.g. if ctx gets cancelled or
	// times out.
	ctx2 := context.Background()

	var sendErr *sender.SendError

	req, err := r.SenderService.SendRequest(ctx2, id)
	if errors.Is(err, proj.ErrNoProject) {
		return nil, noActiveProjectErr(ctx)
	} else if errors.As(err, &sendErr) {
		return nil, &gqlerror.Error{
			Path:    graphql.GetPath(ctx),
			Message: fmt.Sprintf("Sending request failed: %v", sendErr.Unwrap()),
			Extensions: map[string]interface{}{
				"code": "send_request_failed",
			},
		}
	} else if err != nil {
		return nil, fmt.Errorf("could not send request: %w", err)
	}

	senderReq, err := parseSenderRequest(req)
	if err != nil {
		return nil, err
	}

	return &senderReq, nil
}

func (r *mutationResolver) DeleteSenderRequests(ctx context.Context) (*DeleteSenderRequestsResult, error) {
	project, err := r.ProjectService.ActiveProject(ctx)
	if errors.Is(err, proj.ErrNoProject) {
		return nil, noActiveProjectErr(ctx)
	} else if err != nil {
		return nil, fmt.Errorf("could not get active project: %w", err)
	}

	if err := r.SenderService.DeleteRequests(ctx, project.ID); err != nil {
		return nil, fmt.Errorf("could not clear request log: %w", err)
	}

	return &DeleteSenderRequestsResult{true}, nil
}

func parseSenderRequest(req sender.Request) (SenderRequest, error) {
	method := HTTPMethod(req.Method)
	if method != "" && !method.IsValid() {
		return SenderRequest{}, fmt.Errorf("sender request has invalid method: %v", method)
	}

	reqProto := httpProtocolMap[req.Proto]
	if !reqProto.IsValid() {
		return SenderRequest{}, fmt.Errorf("sender request has invalid protocol: %v", req.Proto)
	}

	senderReq := SenderRequest{
		ID:        req.ID,
		URL:       req.URL,
		Method:    method,
		Proto:     HTTPProtocol(req.Proto),
		Timestamp: ulid.Time(req.ID.Time()),
	}

	if req.SourceRequestLogID.Compare(ulid.ULID{}) != 0 {
		senderReq.SourceRequestLogID = &req.SourceRequestLogID
	}

	if req.Header != nil {
		senderReq.Headers = make([]HTTPHeader, 0)

		for key, values := range req.Header {
			for _, value := range values {
				senderReq.Headers = append(senderReq.Headers, HTTPHeader{
					Key:   key,
					Value: value,
				})
			}
		}
	}

	if len(req.Body) > 0 {
		bodyStr := string(req.Body)
		senderReq.Body = &bodyStr
	}

	if req.Response != nil {
		resLog, err := parseResponseLog(*req.Response)
		if err != nil {
			return SenderRequest{}, err
		}

		resLog.ID = req.ID

		senderReq.Response = &resLog
	}

	return senderReq, nil
}

func stringPtrToRegexp(s *string) (*regexp.Regexp, error) {
	if s == nil {
		return nil, nil
	}

	return regexp.Compile(*s)
}

func scopeToScopeRules(rules []scope.Rule) []ScopeRule {
	scopeRules := make([]ScopeRule, len(rules))
	for i, rule := range rules {
		scopeRules[i].URL = regexpToStringPtr(rule.URL)
		if rule.Header.Key != nil || rule.Header.Value != nil {
			scopeRules[i].Header = &ScopeHeader{
				Key:   regexpToStringPtr(rule.Header.Key),
				Value: regexpToStringPtr(rule.Header.Value),
			}
		}

		scopeRules[i].Body = regexpToStringPtr(rule.Body)
	}

	return scopeRules
}

func findRequestsFilterFromInput(input *HTTPRequestLogFilterInput) (filter reqlog.FindRequestsFilter, err error) {
	if input == nil {
		return
	}

	if input.OnlyInScope != nil {
		filter.OnlyInScope = *input.OnlyInScope
	}

	if input.SearchExpression != nil && *input.SearchExpression != "" {
		expr, err := search.ParseQuery(*input.SearchExpression)
		if err != nil {
			return reqlog.FindRequestsFilter{}, fmt.Errorf("could not parse search query: %w", err)
		}

		filter.SearchExpr = expr
	}

	return
}

func findSenderRequestsFilterFromInput(input *SenderRequestFilterInput) (filter sender.FindRequestsFilter, err error) {
	if input == nil {
		return
	}

	if input.OnlyInScope != nil {
		filter.OnlyInScope = *input.OnlyInScope
	}

	if input.SearchExpression != nil && *input.SearchExpression != "" {
		expr, err := search.ParseQuery(*input.SearchExpression)
		if err != nil {
			return sender.FindRequestsFilter{}, fmt.Errorf("could not parse search query: %w", err)
		}

		filter.SearchExpr = expr
	}

	return
}

func findReqFilterToHTTPReqLogFilter(findReqFilter reqlog.FindRequestsFilter) *HTTPRequestLogFilter {
	empty := reqlog.FindRequestsFilter{}
	if findReqFilter == empty {
		return nil
	}

	httpReqLogFilter := &HTTPRequestLogFilter{
		OnlyInScope: findReqFilter.OnlyInScope,
	}

	if findReqFilter.SearchExpr != nil {
		searchExpr := findReqFilter.SearchExpr.String()
		httpReqLogFilter.SearchExpression = &searchExpr
	}

	return httpReqLogFilter
}

func findReqFilterToSenderReqFilter(findReqFilter sender.FindRequestsFilter) *SenderRequestFilter {
	empty := sender.FindRequestsFilter{}
	if findReqFilter == empty {
		return nil
	}

	senderReqFilter := &SenderRequestFilter{
		OnlyInScope: findReqFilter.OnlyInScope,
	}

	if findReqFilter.SearchExpr != nil {
		searchExpr := findReqFilter.SearchExpr.String()
		senderReqFilter.SearchExpression = &searchExpr
	}

	return senderReqFilter
}

func noActiveProjectErr(ctx context.Context) error {
	return &gqlerror.Error{
		Path:    graphql.GetPath(ctx),
		Message: "No active project.",
		Extensions: map[string]interface{}{
			"code": "no_active_project",
		},
	}
}