package jira

import (
	"bytes"
	"fmt"
	"io"
	"mime/multipart"
	"net/url"
	"strings"
	"time"
)

const (
	// AssigneeAutomatic represents the value of the "Assignee: Automatic" of JIRA
	AssigneeAutomatic = "-1"
)

// IssueService handles Issues for the JIRA instance / API.
//
// JIRA API docs: https://docs.atlassian.com/jira/REST/latest/#api/2/issue
type IssueService struct {
	client *Client
}

// Issue represents a JIRA issue.
type Issue struct {
	Expand string       `json:"expand,omitempty"`
	ID     string       `json:"id,omitempty"`
	Self   string       `json:"self,omitempty"`
	Key    string       `json:"key,omitempty"`
	Fields *IssueFields `json:"fields,omitempty"`
}

// Attachment represents a JIRA attachment
type Attachment struct {
	Self      string `json:"self,omitempty"`
	ID        string `json:"id,omitempty"`
	Filename  string `json:"filename,omitempty"`
	Author    *User  `json:"author,omitempty"`
	Created   string `json:"created,omitempty"`
	Size      int    `json:"size,omitempty"`
	MimeType  string `json:"mimeType,omitempty"`
	Content   string `json:"content,omitempty"`
	Thumbnail string `json:"thumbnail,omitempty"`
}

// Epic represents the epic to which an issue is associated
// Not that this struct does not process the returned "color" value
type Epic struct {
	ID      int    `json:"id"`
	Key     string `json:"key"`
	Self    string `json:"self"`
	Name    string `json:"name"`
	Summary string `json:"summary"`
	Done    bool   `json:"done"`
}

// IssueFields represents single fields of a JIRA issue.
// Every JIRA issue has several fields attached.
type IssueFields struct {
	// TODO Missing fields
	//	* "timespent": null,
	//	* "aggregatetimespent": null,
	//	* "workratio": -1,
	//	* "lastViewed": null,
	//	* "timeestimate": null,
	//	* "aggregatetimeoriginalestimate": null,
	//	* "timeoriginalestimate": null,
	//	* "timetracking": {},
	//	* "aggregatetimeestimate": null,
	//	* "environment": null,
	//	* "duedate": null,
	Type              IssueType     `json:"issuetype"`
	Project           Project       `json:"project,omitempty"`
	Resolution        *Resolution   `json:"resolution,omitempty"`
	Priority          *Priority     `json:"priority,omitempty"`
	Resolutiondate    string        `json:"resolutiondate,omitempty"`
	Created           string        `json:"created,omitempty"`
	Watches           *Watches      `json:"watches,omitempty"`
	Assignee          *User         `json:"assignee,omitempty"`
	Updated           string        `json:"updated,omitempty"`
	Description       string        `json:"description,omitempty"`
	Summary           string        `json:"summary"`
	Creator           *User         `json:"Creator,omitempty"`
	Reporter          *User         `json:"reporter,omitempty"`
	Components        []*Component  `json:"components,omitempty"`
	Status            *Status       `json:"status,omitempty"`
	Progress          *Progress     `json:"progress,omitempty"`
	AggregateProgress *Progress     `json:"aggregateprogress,omitempty"`
	Worklog           *Worklog      `json:"worklog,omitempty"`
	IssueLinks        []*IssueLink  `json:"issuelinks,omitempty"`
	Comments          *Comments     `json:"comment,omitempty"`
	FixVersions       []*FixVersion `json:"fixVersions,omitempty"`
	Labels            []string      `json:"labels,omitempty"`
	Subtasks          []*Subtasks   `json:"subtasks,omitempty"`
	Attachments       []*Attachment `json:"attachment,omitempty"`
	Epic              *Epic         `json:"epic,omitempty"`
}

// IssueType represents a type of a JIRA issue.
// Typical types are "Request", "Bug", "Story", ...
type IssueType struct {
	Self        string `json:"self,omitempty"`
	ID          string `json:"id,omitempty"`
	Description string `json:"description,omitempty"`
	IconURL     string `json:"iconUrl,omitempty"`
	Name        string `json:"name,omitempty"`
	Subtask     bool   `json:"subtask,omitempty"`
	AvatarID    int    `json:"avatarId,omitempty"`
}

// Resolution represents a resolution of a JIRA issue.
// Typical types are "Fixed", "Suspended", "Won't Fix", ...
type Resolution struct {
	Self        string `json:"self"`
	ID          string `json:"id"`
	Description string `json:"description"`
	Name        string `json:"name"`
}

// Priority represents a priority of a JIRA issue.
// Typical types are "Normal", "Moderate", "Urgent", ...
type Priority struct {
	Self    string `json:"self,omitempty"`
	IconURL string `json:"iconUrl,omitempty"`
	Name    string `json:"name,omitempty"`
	ID      string `json:"id,omitempty"`
}

// Watches represents a type of how many user are "observing" a JIRA issue to track the status / updates.
type Watches struct {
	Self       string `json:"self,omitempty"`
	WatchCount int    `json:"watchCount,omitempty"`
	IsWatching bool   `json:"isWatching,omitempty"`
}

// User represents a user who is this JIRA issue assigned to.
type User struct {
	Self         string     `json:"self,omitempty"`
	Name         string     `json:"name,omitempty"`
	Key          string     `json:"key,omitempty"`
	EmailAddress string     `json:"emailAddress,omitempty"`
	AvatarUrls   AvatarUrls `json:"avatarUrls,omitempty"`
	DisplayName  string     `json:"displayName,omitempty"`
	Active       bool       `json:"active,omitempty"`
	TimeZone     string     `json:"timeZone,omitempty"`
}

// AvatarUrls represents different dimensions of avatars / images
type AvatarUrls struct {
	Four8X48  string `json:"48x48,omitempty"`
	Two4X24   string `json:"24x24,omitempty"`
	One6X16   string `json:"16x16,omitempty"`
	Three2X32 string `json:"32x32,omitempty"`
}

// Component represents a "component" of a JIRA issue.
// Components can be user defined in every JIRA instance.
type Component struct {
	Self string `json:"self,omitempty"`
	ID   string `json:"id,omitempty"`
	Name string `json:"name,omitempty"`
}

// Status represents the current status of a JIRA issue.
// Typical status are "Open", "In Progress", "Closed", ...
// Status can be user defined in every JIRA instance.
type Status struct {
	Self           string         `json:"self"`
	Description    string         `json:"description"`
	IconURL        string         `json:"iconUrl"`
	Name           string         `json:"name"`
	ID             string         `json:"id"`
	StatusCategory StatusCategory `json:"statusCategory"`
}

// StatusCategory represents the category a status belongs to.
// Those categories can be user defined in every JIRA instance.
type StatusCategory struct {
	Self      string `json:"self"`
	ID        int    `json:"id"`
	Name      string `json:"name"`
	Key       string `json:"key"`
	ColorName string `json:"colorName"`
}

// Progress represents the progress of a JIRA issue.
type Progress struct {
	Progress int `json:"progress"`
	Total    int `json:"total"`
}

// Time represents the Time definition of JIRA as a time.Time of go
type Time time.Time

// Wrapper struct for search result
type transitionResult struct {
	Transitions []Transition `json:"transitions"`
}

// Transition represents an issue transition in JIRA
type Transition struct {
	ID     string                     `json:"id"`
	Name   string                     `json:"name"`
	Fields map[string]TransitionField `json:"fields"`
}

// TransitionField represents the value of one Transistion
type TransitionField struct {
	Required bool `json:"required"`
}

// CreateTransitionPayload is used for creating new issue transitions
type CreateTransitionPayload struct {
	Transition TransitionPayload `json:"transition"`
}

// TransitionPayload represents the request payload of Transistion calls like DoTransition
type TransitionPayload struct {
	ID string `json:"id"`
}

// UnmarshalJSON will transform the JIRA time into a time.Time
// during the transformation of the JIRA JSON response
func (t *Time) UnmarshalJSON(b []byte) error {
	ti, err := time.Parse("\"2006-01-02T15:04:05.999-0700\"", string(b))
	if err != nil {
		return err
	}
	*t = Time(ti)
	return nil
}

// Worklog represents the work log of a JIRA issue.
// One Worklog contains zero or n WorklogRecords
// JIRA Wiki: https://confluence.atlassian.com/jira/logging-work-on-an-issue-185729605.html
type Worklog struct {
	StartAt    int             `json:"startAt"`
	MaxResults int             `json:"maxResults"`
	Total      int             `json:"total"`
	Worklogs   []WorklogRecord `json:"worklogs"`
}

// WorklogRecord represents one entry of a Worklog
type WorklogRecord struct {
	Self             string `json:"self"`
	Author           User   `json:"author"`
	UpdateAuthor     User   `json:"updateAuthor"`
	Comment          string `json:"comment"`
	Created          Time   `json:"created"`
	Updated          Time   `json:"updated"`
	Started          Time   `json:"started"`
	TimeSpent        string `json:"timeSpent"`
	TimeSpentSeconds int    `json:"timeSpentSeconds"`
	ID               string `json:"id"`
	IssueID          string `json:"issueId"`
}

// Subtasks represents all issues of a parent issue.
type Subtasks struct {
	ID     string      `json:"id"`
	Key    string      `json:"key"`
	Self   string      `json:"self"`
	Fields IssueFields `json:"fields"`
}

// IssueLink represents a link between two issues in JIRA.
type IssueLink struct {
	ID           string        `json:"id,omitempty"`
	Self         string        `json:"self,omitempty"`
	Type         IssueLinkType `json:"type"`
	OutwardIssue *Issue        `json:"outwardIssue"`
	InwardIssue  *Issue        `json:"inwardIssue"`
	Comment      *Comment      `json:"comment,omitempty"`
}

// IssueLinkType represents a type of a link between to issues in JIRA.
// Typical issue link types are "Related to", "Duplicate", "Is blocked by", etc.
type IssueLinkType struct {
	ID      string `json:"id,omitempty"`
	Self    string `json:"self,omitempty"`
	Name    string `json:"name"`
	Inward  string `json:"inward"`
	Outward string `json:"outward"`
}

// Comments represents a list of Comment.
type Comments struct {
	Comments []*Comment `json:"comments,omitempty"`
}

// Comment represents a comment by a person to an issue in JIRA.
type Comment struct {
	ID           string            `json:"id,omitempty"`
	Self         string            `json:"self,omitempty"`
	Name         string            `json:"name,omitempty"`
	Author       User              `json:"author,omitempty"`
	Body         string            `json:"body,omitempty"`
	UpdateAuthor User              `json:"updateAuthor,omitempty"`
	Updated      string            `json:"updated,omitempty"`
	Created      string            `json:"created,omitempty"`
	Visibility   CommentVisibility `json:"visibility,omitempty"`
}

// FixVersion represents a software release in which an issue is fixed.
type FixVersion struct {
	Archived        *bool  `json:"archived,omitempty"`
	ID              string `json:"id,omitempty"`
	Name            string `json:"name,omitempty"`
	ProjectID       int    `json:"projectId,omitempty"`
	ReleaseDate     string `json:"releaseDate,omitempty"`
	Released        *bool  `json:"released,omitempty"`
	Self            string `json:"self,omitempty"`
	UserReleaseDate string `json:"userReleaseDate,omitempty"`
}

// CommentVisibility represents he visibility of a comment.
// E.g. Type could be "role" and Value "Administrators"
type CommentVisibility struct {
	Type  string `json:"type,omitempty"`
	Value string `json:"value,omitempty"`
}

// SearchOptions specifies the optional parameters to various List methods that
// support pagination.
// Pagination is used for the JIRA REST APIs to conserve server resources and limit
// response size for resources that return potentially large collection of items.
// A request to a pages API will result in a values array wrapped in a JSON object with some paging metadata
// Default Pagination options
type SearchOptions struct {
	// StartAt: The starting index of the returned projects. Base index: 0.
	StartAt int `url:"startAt,omitempty"`
	// MaxResults: The maximum number of projects to return per page. Default: 50.
	MaxResults int `url:"maxResults,omitempty"`
}

// searchResult is only a small wrapper arround the Search (with JQL) method
// to be able to parse the results
type searchResult struct {
	Issues     []Issue `json:"issues"`
	StartAt    int     `json:"startAt"`
	MaxResults int     `json:"maxResults"`
	Total      int     `json:"total"`
}

// CustomFields represents custom fields of JIRA
// This can heavily differ between JIRA instances
type CustomFields map[string]string

// Get returns a full representation of the issue for the given issue key.
// JIRA will attempt to identify the issue by the issueIdOrKey path parameter.
// This can be an issue id, or an issue key.
// If the issue cannot be found via an exact match, JIRA will also look for the issue in a case-insensitive way, or by looking to see if the issue was moved.
//
// JIRA API docs: https://docs.atlassian.com/jira/REST/latest/#api/2/issue-getIssue
func (s *IssueService) Get(issueID string) (*Issue, *Response, error) {
	apiEndpoint := fmt.Sprintf("rest/api/2/issue/%s", issueID)
	req, err := s.client.NewRequest("GET", apiEndpoint, nil)
	if err != nil {
		return nil, nil, err
	}

	issue := new(Issue)
	resp, err := s.client.Do(req, issue)
	if err != nil {
		return nil, resp, err
	}

	return issue, resp, nil
}

// DownloadAttachment returns a Response of an attachment for a given attachmentID.
// The attachment is in the Response.Body of the response.
// This is an io.ReadCloser.
// The caller should close the resp.Body.
func (s *IssueService) DownloadAttachment(attachmentID string) (*Response, error) {
	apiEndpoint := fmt.Sprintf("secure/attachment/%s/", attachmentID)
	req, err := s.client.NewRequest("GET", apiEndpoint, nil)
	if err != nil {
		return nil, err
	}

	resp, err := s.client.Do(req, nil)
	if err != nil {
		return resp, err
	}

	return resp, nil
}

// PostAttachment uploads r (io.Reader) as an attachment to a given attachmentID
func (s *IssueService) PostAttachment(attachmentID string, r io.Reader, attachmentName string) (*[]Attachment, *Response, error) {
	apiEndpoint := fmt.Sprintf("rest/api/2/issue/%s/attachments", attachmentID)

	b := new(bytes.Buffer)
	writer := multipart.NewWriter(b)

	fw, err := writer.CreateFormFile("file", attachmentName)
	if err != nil {
		return nil, nil, err
	}

	if r != nil {
		// Copy the file
		if _, err = io.Copy(fw, r); err != nil {
			return nil, nil, err
		}
	}
	writer.Close()

	req, err := s.client.NewMultiPartRequest("POST", apiEndpoint, b)
	if err != nil {
		return nil, nil, err
	}

	req.Header.Set("Content-Type", writer.FormDataContentType())

	// PostAttachment response returns a JSON array (as multiple attachments can be posted)
	attachment := new([]Attachment)
	resp, err := s.client.Do(req, attachment)
	if err != nil {
		return nil, resp, err
	}

	return attachment, resp, nil
}

// Create creates an issue or a sub-task from a JSON representation.
// Creating a sub-task is similar to creating a regular issue, with two important differences:
// The issueType field must correspond to a sub-task issue type and you must provide a parent field in the issue create request containing the id or key of the parent issue.
//
// JIRA API docs: https://docs.atlassian.com/jira/REST/latest/#api/2/issue-createIssues
func (s *IssueService) Create(issue *Issue) (*Issue, *Response, error) {
	apiEndpoint := "rest/api/2/issue/"
	req, err := s.client.NewRequest("POST", apiEndpoint, issue)
	if err != nil {
		return nil, nil, err
	}

	responseIssue := new(Issue)
	resp, err := s.client.Do(req, responseIssue)
	if err != nil {
		return nil, resp, err
	}

	return responseIssue, resp, nil
}

// AddComment adds a new comment to issueID.
//
// JIRA API docs: https://docs.atlassian.com/jira/REST/latest/#api/2/issue-addComment
func (s *IssueService) AddComment(issueID string, comment *Comment) (*Comment, *Response, error) {
	apiEndpoint := fmt.Sprintf("rest/api/2/issue/%s/comment", issueID)
	req, err := s.client.NewRequest("POST", apiEndpoint, comment)
	if err != nil {
		return nil, nil, err
	}

	responseComment := new(Comment)
	resp, err := s.client.Do(req, responseComment)
	if err != nil {
		return nil, resp, err
	}

	return responseComment, resp, nil
}

// AddLink adds a link between two issues.
//
// JIRA API docs: https://docs.atlassian.com/jira/REST/latest/#api/2/issueLink
func (s *IssueService) AddLink(issueLink *IssueLink) (*Response, error) {
	apiEndpoint := fmt.Sprintf("rest/api/2/issueLink")
	req, err := s.client.NewRequest("POST", apiEndpoint, issueLink)
	if err != nil {
		return nil, err
	}

	resp, err := s.client.Do(req, nil)
	return resp, err
}

// Search will search for tickets according to the jql
//
// JIRA API docs: https://developer.atlassian.com/jiradev/jira-apis/jira-rest-apis/jira-rest-api-tutorials/jira-rest-api-example-query-issues
func (s *IssueService) Search(jql string, options *SearchOptions) ([]Issue, *Response, error) {
	var u string
	if options == nil {
		u = fmt.Sprintf("rest/api/2/search?jql=%s", url.QueryEscape(jql))
	} else {
		u = fmt.Sprintf("rest/api/2/search?jql=%s&startAt=%d&maxResults=%d", url.QueryEscape(jql),
			options.StartAt, options.MaxResults)
	}

	req, err := s.client.NewRequest("GET", u, nil)
	if err != nil {
		return []Issue{}, nil, err
	}

	v := new(searchResult)
	resp, err := s.client.Do(req, v)
	return v.Issues, resp, err
}

// GetCustomFields returns a map of customfield_* keys with string values
func (s *IssueService) GetCustomFields(issueID string) (CustomFields, *Response, error) {
	apiEndpoint := fmt.Sprintf("rest/api/2/issue/%s", issueID)
	req, err := s.client.NewRequest("GET", apiEndpoint, nil)
	if err != nil {
		return nil, nil, err
	}

	issue := new(map[string]interface{})
	resp, err := s.client.Do(req, issue)
	if err != nil {
		return nil, resp, err
	}

	m := *issue
	f := m["fields"]
	cf := make(CustomFields)
	if f == nil {
		return cf, resp, nil
	}

	if rec, ok := f.(map[string]interface{}); ok {
		for key, val := range rec {
			if strings.Contains(key, "customfield") {
				cf[key] = fmt.Sprint(val)
			}
		}
	}
	return cf, resp, nil
}

// GetTransitions gets a list of the transitions possible for this issue by the current user,
// along with fields that are required and their types.
//
// JIRA API docs: https://docs.atlassian.com/jira/REST/latest/#api/2/issue-getTransitions
func (s *IssueService) GetTransitions(id string) ([]Transition, *Response, error) {
	apiEndpoint := fmt.Sprintf("rest/api/2/issue/%s/transitions?expand=transitions.fields", id)
	req, err := s.client.NewRequest("GET", apiEndpoint, nil)
	if err != nil {
		return nil, nil, err
	}

	result := new(transitionResult)
	resp, err := s.client.Do(req, result)
	return result.Transitions, resp, err
}

// DoTransition performs a transition on an issue.
// When performing the transition you can update or set other issue fields.
//
// JIRA API docs: https://docs.atlassian.com/jira/REST/latest/#api/2/issue-doTransition
func (s *IssueService) DoTransition(ticketID, transitionID string) (*Response, error) {
	apiEndpoint := fmt.Sprintf("rest/api/2/issue/%s/transitions", ticketID)

	payload := CreateTransitionPayload{
		Transition: TransitionPayload{
			ID: transitionID,
		},
	}
	req, err := s.client.NewRequest("POST", apiEndpoint, payload)
	if err != nil {
		return nil, err
	}

	resp, err := s.client.Do(req, nil)
	if err != nil {
		return nil, err
	}

	return resp, nil
}