package main

/*
   This file is part of taler-dashboard
   Copyright (C) 2023 Özgür Kesim

   taler-dashboard is free software; you can redistribute it and/or modify it
   under the terms of the GNU Affero General Public License as published by the
   Free Software Foundation; either version 3, or (at your option) any later
   version.

   taler-dashboard is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public
   License for more details.

   You can receive a copy of the GNU Affero General Public License from
   <http://www.gnu.org/licenses/>

   @author Özgür Kesim <oec-taler@kesim.org>
*/

import (
	"context"
	"encoding/json"
	"fmt"
	"html/template"
	"io"
	"log"
	"net/http"
	"runtime/debug"
	"sort"
	"strings"
	"sync"
	"time"
)

type Data struct {
	mux            sync.RWMutex
	url            string
	token          string
	num            int
	projectId      int
	minimumVersion string
	tmpl           *template.Template
	ctx            context.Context

	Issues    Issues
	Features  Issues
	Project   Project
	Timestamp time.Time
	Freq      time.Duration
	Lasterror error
}

func NewData(ctx context.Context, url, token string, num int) *Data {
	data := &Data{
		url:   url,
		token: token,
		ctx:   ctx,
		num:   num,
	}
	fm := map[string]any{
		"shorten": func(max int, s string) string {
			if len(s) <= max {
				return s
			}
			return s[:max] + "⋯"
		},
	}
	data.tmpl = template.Must(template.New("index").Funcs(fm).ParseFS(content, "*.tmpl"))

	return data
}

func (d *Data) getProject() {
	url := fmt.Sprintf("%s/projects/%d", d.url, d.projectId)
	req, e := http.NewRequestWithContext(d.ctx, "GET", url, nil)
	if nil != e {
		d.mux.Lock()
		defer d.mux.Unlock()
		d.Lasterror = e
		return
	}
	req.Header.Add("Authorization", d.token)

	r, e := http.DefaultClient.Do(req)
	if nil != e {
		d.mux.Lock()
		defer d.mux.Unlock()
		d.Lasterror = e
		return
	} else if 200 != r.StatusCode {
		d.mux.Lock()
		defer d.mux.Unlock()
		d.Lasterror = fmt.Errorf("Got unexpected status %s\n", r.Status)
		return
	}

	var project Project
	p := struct{ Projects []Project }{}
	e = json.NewDecoder(r.Body).Decode(&p)

	if len(p.Projects) < 1 {
		e = fmt.Errorf("no project found with id", d.projectId)
	} else {
		// filter out obsolete versions
		project = p.Projects[0]
		var versions Versions
		for _, v := range project.Versions {
			v := v
			if !v.Obsolete && !v.Released {
				versions = append(versions, v)
			}
		}
		project.Versions = versions
	}

	d.mux.Lock()
	defer d.mux.Unlock()
	d.Lasterror = e
	if nil != e {
		return
	}

	d.Timestamp = time.Now()
	d.Project = project

	log.Println("Got project details for id", d.projectId, "with", len(d.Project.Versions), "version entries")
}

const statusFilter = `status%5B%5D=10&status%5B%5D=20&status%5B%5D=30&status%5B%5D=40&status%5B%5D=50&severity%5B%5D=20`

var fields = []string{"id",
	"description",
	"summary",
	"category",
	"target_version",
	"status",
	"reporter",
	"handler",
	"resolution",
	"priority",
	"severity",
	"created_at",
	"updated_at",
	"relationships",
	"tags",
}

func (d *Data) getIssues() {
	url := fmt.Sprintf("%s/issues?project_id=%d&page_size=%d&%s&select=%s",
		d.url, d.projectId, d.num, statusFilter,
		strings.Join(fields, ","))
	req, e := http.NewRequestWithContext(d.ctx, "GET", url, nil)
	if nil != e {
		d.mux.Lock()
		defer d.mux.Unlock()
		d.Lasterror = e
		return
	}
	req.Header.Add("Authorization", d.token)

	r, e := http.DefaultClient.Do(req)
	if nil != e {
		d.mux.Lock()
		defer d.mux.Unlock()
		d.Lasterror = e
		return
	} else if 200 != r.StatusCode {
		d.mux.Lock()
		defer d.mux.Unlock()
		d.Lasterror = fmt.Errorf("Got unexpected status %s\n", r.Status)
		return
	}

	iss := struct{ Issues Issues }{}
	e = json.NewDecoder(r.Body).Decode(&iss)

	d.mux.Lock()
	defer d.mux.Unlock()
	d.Lasterror = e
	if nil != e {
		return
	}
	d.Timestamp = time.Now()

	// Filter issues with old target versions out
	var issues = Issues{}
	var features = Issues{}
	var open = 0
	for _, issue := range iss.Issues {
		if issue.Resolution.Name == "open" &&
			strings.Compare(d.minimumVersion, issue.TargetVersion.Name) < 0 {
			open++
			if issue.Severity.Name == "feature" {
				features = append(features, issue)
			} else {
				issues = append(issues, issue)
			}
		}
	}
	d.Issues = issues
	d.Features = features
	log.Println("Got", len(iss.Issues), "entries, of which", open, "are open and relevant:", len(features), "features and", len(issues), "issues")
}

func (d *Data) Loop() {
	d.getProject()
	d.getIssues()
	go func() {
		var ticker = time.NewTicker(d.Freq)
		for range ticker.C {
			select {
			case <-d.ctx.Done():
				return
			default:
				log.Println("Updating data")
				d.getProject()
				d.getIssues()
			}
		}
	}()
}

func (d *Data) printJSON(w io.Writer) {
	d.mux.RLock()
	defer d.mux.RUnlock()

	if nil == d.Issues {
		fmt.Fprintln(w, "{}")
		return
	}
	enc := json.NewEncoder(w)
	enc.SetIndent("", " ")
	enc.Encode(d.Issues)
}

func (d *Data) printTemplate(w io.Writer, name string) {
	d.mux.RLock()
	defer d.mux.RUnlock()
	e := d.tmpl.ExecuteTemplate(w, name, d)
	if nil != e {
		log.Println(e)
	}
}

func (d *Data) TargetVersions() (tv []string) {
	d.mux.RLock()
	defer d.mux.RUnlock()

	var m = map[string]bool{}
	for _, s := range d.Issues.TargetVersions() {
		m[s] = true
	}
	for _, s := range d.Features.TargetVersions() {
		m[s] = true
	}
	for s := range m {
		tv = append(tv, s)
	}
	sort.Strings(tv)
	return
}

func (d *Data) VersionsByDate() VersionsByDate {
	return VersionsByDate(d.Project.Versions)
}

func (d *Data) Categories() (cs []string) {
	d.mux.RLock()
	defer d.mux.RUnlock()

	var m = map[string]bool{}
	for _, s := range d.Issues.Categories() {
		m[s] = true
	}
	for _, s := range d.Features.Categories() {
		m[s] = true
	}
	for s := range m {
		cs = append(cs, s)
	}
	sort.Strings(cs)
	return
}

func (d *Data) Tags() (ts []string) {
	d.mux.RLock()
	defer d.mux.RUnlock()

	var m = map[string]bool{}
	for _, s := range d.Issues.Tags() {
		m[s] = true
	}
	for _, s := range d.Features.Tags() {
		m[s] = true
	}
	for s := range m {
		ts = append(ts, s)
	}
	sort.Strings(ts)
	return
}

func (d *Data) Commit() string {
	var version, timestamp = "<unknown>", "<unknown>"
	if info, ok := debug.ReadBuildInfo(); ok {
		for _, setting := range info.Settings {
			switch setting.Key {
			case "vcs.revision":
				n := len(setting.Value)
				if n > 8 {
					n = 8
				}
				version = setting.Value[:n]
			case "vcs.time":
				timestamp = setting.Value
			}
		}
	}

	return version + " from " + timestamp
}