// The package provides a series of data structures for interaction with and
// interpolation of issues.
//
// At its most basic level, an issue is a simple collection of strings of text,
// with no specific implementation requirements, aside from their existance.
// As per spec, issues are simply folders with specific named plain text files.
// Two of those files require the files to have data, while the rest do not require
// associated data.
//
// The only two mandatory files to pass spec are the "description" file
// ($ISSUE_PATH/description) and the "status" file ($ISSUE_PATH/status):
//
//   - the description file:
//
//     An issue's description should have, at the least, a descriptive title.
//     The authors recommend following the Git Commit basic style guidelines.
//
//   - the status file:
//
//     An issue's status file should contain at minimum a human readable one
//     line description of the status' current state. For example, "open" or
//     "closed." The authors recommend using a semicolon to separate assignments
//     or related goals. For example, "assigned:arianagiroux" or "bug:critical".
//
// These couplings of files and subsequent file data are represented via the Field
// struct. Each Field struct has the following fields:
//
//   - The file's path (Field.Path), relative to the issue's root path, and
//
//   - The file's contents (Field.Data)
//
// Example:
//
//	 ...
//		// define a new Field
//		description := Field.New(data_from_file, path_relative_to_root)
//		// OR
//		description := Field.NewFromPath(path_to_file) // NOT IMPLEMENTED AS OF 0.0.3
//
// The spec additionally outlines optional implementations of "tags" and
// "blockers". What the developer uses these for is up to them. Both are treated
// similarly, where tags are located in a directory named "tags", and blockers
// are located in a directory named "blockedby". The spec does not outline any
// use for the content of these plain files, and (as of 0.0.3) issues does not
// load the data from these files.
//
// Note: the files within the "blockedby" folder are referred to as both "Blockers"
// and "Blockedby" interchangeably throughout the package, where applicable.
//
// The package defines the struct "VariadicField" to facilitate both "tags" and
// "blockers". Theoretically, it can facilitate any folder that matches the
// restraints as outlined by the spec. A VariadicField is, at its core, a slice
// of Field objects with an associated path. This is ensure that it's underlying
// []Field object is associated with a path on disk.
//
// Example:
//
//	...
//	// define some Fields
//	fields := []Field{{path:"tag1"}, {path:"tag2"}}
//	// define a new VariadicField
//	tags := VariadicField.New(fields, "/tags")
//	// OR
//	tags := VariadicField{Fields:fields, Path:"/tags"}
//	// OR
//	tags := VariadicField{path:"/tags"}.NewFromPath("an_issue/tags")
//
// The Issue struct utilizes both Field and VariadicField structs to represent
// a full spec compliant issue. While it is possible to instantiate the struct
// directly, it is not recommended. The struct provides two constructor functions,
// which handles parsing spec confoming issue "titles" (read: root issue path)
// as human readable strings.
//
// Example:
//
//	...
//	// data prep
//	description := Field{Path:"/description", Data:"a descriptive blurb"}
//	status := Field{Path:"/status", Data:"open"}
//	tags := VariadicField{Path:"/tags"}
//	blockers := VariadicField{Path:"/blockedby"}
//	path := "issues/an_issue"
//	...
//	// new Issue with custom title
//	customTitleIssue := Issue.New(Issue{}, "A Custom Title",
//			description, status, tags, blockers, path)
//	// new Issue, automatic title
//	autoTitleIssue := Issue.New(Issue{}, "",
//			description, status, tags, blockers, path)
//	// new Issue from path on disk
//	issueFromDisk := Issue.NewFroMPath(Issue{}, "issues/an_issue")
//
// Finally, the package defines a simple data structure for a collection of
// issues: the "IssueCollection". This is a simple slice of Issues ([]Issue).
package issues

import (
	"os"
	"path/filepath"
	"strings"
)

// Issue Definitions ------------------------------------------------------------
// ----------------------------------------------------------------------------

type Issue struct {
	Title       string        // The title of the bug in human readable format
	Description Field         // The description of the bug
	Status      Field         // The status of the bug
	Tags        VariadicField // A slice of VariadicFields
	Blockedby   VariadicField // A slice of VariadicFields
	Path        string        // The path to the bug

	// machineTitle string        // The machine parseable bug title
}

// Constrcutor for Issues
func (i Issue) New(title string, description Field, status Field, tags VariadicField, blockedby VariadicField, path string) (issue Issue, err error) {
	if len(title) == 0 {
		title = parsePathToHuman(path)
	}
	return Issue{
		Title:       title,
		Description: description,
		Status:      status,
		Tags:        tags,
		Blockedby:   blockedby,
		Path:        path,
	}, err
}

// Constrcutor for Issues that loads relevant data from disk
func (i Issue) NewFromPath(path string) (bug Issue, err error) {
	// Required Fields
	description := &Field{Path: "/description"}
	status := &Field{Path: "/status"}
	requiredFields := []*Field{description, status}

	for _, field := range requiredFields {
		data, err := readPath(path + field.Path)
		if err != nil {
			return Issue{}, err
		}

		field.Data = strings.TrimRight(data, "\n")
	}

	// Variadic Fields
	tags := VariadicField{Path: "/tags"}
	blockers := VariadicField{Path: "/blockedby"}

	tags, _ = VariadicField.NewFromPath(tags, path)
	blockers, _ = VariadicField.NewFromPath(blockers, path)
	// we can ignore the errors, as loadVariadicField already gracefully handles
	//them.

	// title from path
	title := parsePathToHuman(path)

	return Issue{
		Title:       title,
		Description: *description,
		Status:      *status,
		Tags:        tags,
		Blockedby:   blockers,
		Path:        path,
	}, err
}

// Field Definitions ----------------------------------------------------------
// ----------------------------------------------------------------------------

// A struct representing data that is tied to data on disk
type Field struct {
	Path string
	Data string
}

// Constructor for Fields
func (f Field) New(data string, path string) Field { return Field{Data: data, Path: path} }

// VariadicField Definitions --------------------------------------------------
// ----------------------------------------------------------------------------

// VariadicFields hold lists of Field objects.
type VariadicField struct {
	Path   string  // The associated path on disk of Fields represented by Variadic Field
	Fields []Field // The underlying slice of Field objects
}

// Constructor for VariadicFields
func (vf VariadicField) New(fields []Field, path string) VariadicField {
	return VariadicField{Fields: fields, Path: path}
}

// Constructor for VariadicFields that loads relevant data from disk
func (vf VariadicField) NewFromPath(pathOnDisk string) (v VariadicField, err error) {
	rootPath := pathOnDisk + "/" + vf.Path

	files, err := os.ReadDir(rootPath)
	if err != nil {
		return vf, err
	}

	for _, file := range files {
		data, err := readPath(rootPath + "/" + file.Name())
		if err != nil {
			return vf, err
		}
		if file.Name()[0:1] == "." {
			continue
		}

		vf.Fields = append(vf.Fields, Field{Data: strings.TrimRight(data, "\n"), Path: file.Name()})
	}

	return vf, err
}

func (vf VariadicField) AsString() string {
	var output string
	for _, field := range vf.Fields {
		output = output + strings.TrimRight(field.Path, " \t\n") + ", "
	}

	output = strings.TrimRight(output, ", ")

	return output
}

// IssueCollection Definitions ------------------------------------------------
// ----------------------------------------------------------------------------

type IssueCollection struct {
	Collection []Issue
	Path       string
	selection  int
}

func (ic IssueCollection) NewFromPath(path string) (collection IssueCollection, err error) {
	ic.Path = path
	files, err := os.ReadDir(path)
	if err != nil {
		return IssueCollection{}, err
	}

	for _, file := range files {
		issuePath := path + "/" + file.Name()
		if IsIssue(issuePath) {
			issue, err := Issue.NewFromPath(Issue{}, issuePath)
			if err != nil {
				continue
			}

			ic.Collection = append(ic.Collection, issue)
		}
	}

	return ic, nil
}

// Util Definitions -----------------------------------------------------------
// ----------------------------------------------------------------------------

// Parses human readable strings as path strings
func parseHumanToPath(humanReadable string) string {
	var out string
	out = strings.ReplaceAll(humanReadable, "-", "\\replace/")
	out = strings.ReplaceAll(out, " ", "-")
	out = strings.ReplaceAll(out, "\\replace/", "--")

	return out
}

// Parses machine parseable paths as human readable strings
func parsePathToHuman(path string) string {
	_, last := filepath.Split(filepath.Clean(path))
	last = strings.ReplaceAll(last, "--", "\\replace/")
	last = strings.ReplaceAll(last, "-", " ")
	last = strings.ReplaceAll(last, "\\replace/", "-")

	return last
}